From The Space Review: National Space Strategy: proactive or reactive?
Where there is no vision, the people perish” – Proverbs 29:18
“…space preeminence is essential if the US is to be a great power and continue to be a great power.” – Major General James Armor, USAF (Retired)
Throughout its history, America has notoriously been reactive when it comes to its national strategy. The United States was the nation to invent the powered airplane, but was slow to realize its potential until European powers seized the opportunity. When it came to space, some historians argue that had the Soviet Union not orbited a satellite and later a cosmonaut, there would have been no Apollo program or human space program of the kind we think of when the phrase “spacepower” is bandied about. In those situations, America had the industrial might and political fortitude to see the threats at hand to their global influence as a superpower on the world stage. However, recently some events have been occurring in the space frontier that seems to indicate a lack of vision and highlights the need for a national space strategy: space based solar power (SBSP) in China.
Recently, the Chinese have committed to the development and deployment of SBSP architectures as a vital part of the nation’s “future direction”, according to a paper by three space scientists from the China Academy of Space Technology.
Many may read that last sentence and wonder, “What’s the big deal about the Chinese experimenting with SBSP?” As many in the United States government and elsewhere believe, SBSP is the stuff of science fiction; pipe dreams of space advocacy groups that aren’t found in the real world. However, since the publication of the National Security Space Office’s analysis of the security implications of SBSP, the Chinese have seen that SBSP is not necessarily a pipe dream, has economic and political merit, and is important to China in the future.
Recently, the Chinese have committed to the development and deployment of SBSP architectures in low earth orbit (LEO) and geostationary Earth orbit (GEO) as a vital part of the nation’s “future direction”, according to a paper by three space scientists from the China Academy of Space Technology (CAST). This new effort demonstrates Chinese resolve toward a sustainable and long-term strategy for their nation that sees space as the vital national interest and instrument of power that it is. It enables positive advantages in several areas of global power and influence, three of which are economic power, technological prowess, and innovation. All of these enable their planned achievement of global leadership and preeminence in space.
Why this push for SBSP in China? Their global interests are increasing due to their economic growth and reach on several continents. As a result, natural resources and energy will become increasingly critical to their goals. With their growing dominance of vital space- and weapons-related resources like rare earth metals, and other natural resources such as oil, the Chinese see themselves as a leading economic power in the world. This increased economic power has helped increase their role in international financial and diplomatic institutions. Because of this increasing need for energy resources to advance their economic growth and power, the Chinese government has been exploring new options for future resources “inside earth” but acknowledge their needs might surpass the natural resources they have access to. This has prompted the Chinese government to look to space.
According to the paper by CAST, “the state has decided that power from outside the earth, such as solar power and the development of other space energy resources is to be China’s future direction.” This is not a mere statement of desire as is the case in many circles of the United States space advocacy arena; rather it is a real program that is “currently under development in China”.
Having the necessary access to space-based energy resources will enable the Chinese to “sustainably develop” and meet the “thirst for energy to water its blooming industries” that have created it as “one of the principal economies in the world. “ To achieve this goal of power and influence economically, the Chinese have developed a national strategy that explores three advantages of SBSP: sustainable economic and social development, disaster prevention and mitigation, and cultivating innovative talents through an increased space effort the likes of which haven’t been seen since the Apollo program. This would require technological innovation on a grand strategic scale.
According to the CAST paper, “The acquisition of space solar power will require development of fundamental new aerospace technologies, such as revolutionary launch approaches, ultra-thin solar arrays, on-orbit manufacture/assembly/integration (MAI), precise attitude control, in-situ resource utilization for deep space exploration and space colonial expansion.” This demonstrates that SBSP is not just one project for economic leadership of China, but part of a grand strategy of space power expansion and a desire to be the leading space power on Earth. They acknowledge this through the comparison of the Apollo project and its benefits for the United States. “In the last century, America’s leading position in science and technology worldwide was inextricably linked with technological advances associated with implementation of the Apollo program. Likewise, China’s current achievements in aerospace technology are built upon with its successive generations of satellite projects in space, China will use its capabilities in space science to assure…” the Chinese development of space development and energy in space.
While this is a long-range plan, the fact that the Chinese are proceeding with its development in conjunction with their efforts in the economic and military/human spaceflight spheres shows a resolve and foresighted strategy.
As mentioned previously, China’s desire is to be recognized as the leader in space. To do this, and to support their future economic power and influence worldwide, energy development and the applications of space resources are the way forward. Their human spaceflight program, including the recent launch of Tiangong 1 and the autonomous rendezvous and docking technologies they are developing, will enable the new technologies needed for this SBSP architecture as well as Chinese long-range plans for deep space exploration and “colonial expansion”.
This plan for space includes the following five-step plan to achieve their SBSP plans (concurrently with their space station development and other programs):
2010: CAST finished their concept design
2020: Finish the industrial level testing of in-orbit construction and wireless transmissions
2025: Complete the first 100kW SBSP demonstration in LEO
2050: The first operational level SBSP system will be deployed in GEO.
While this is a long-range plan, the fact that the Chinese are proceeding with its development in conjunction with their efforts in the economic and military/human spaceflight spheres shows a resolve and foresighted strategy that understands the need and strategic impact that space power has on the balance of power and influence in the world. Even if many in America and elsewhere believe that the United States is the undisputed leader in space exploration and development, one need only look at the America’s current space strategy to find the difference in the visions for national space leadership in the two nations. Compared with the Chinese, the United States does not have a long-range national space strategy or direction, and desperately needs one.
Leadership in space should not be assumed: it requires hard, continued work to assure its existence into the future.
What is the United States doing about this challenge to its global leadership in space and economic matters? Not much. In March 2011, the Obama Administration released its “Blueprint for a Secure Energy Future”, but that document doesn’t mention SBSP at all, even as something worthy of consideration. In the National Space Policy of 2010, the Obama Administration mentions space nuclear power—as past policies have—but does not mention any effort to develop SBSP for the United States or its allies, much less the “colonial expansion” that the Chinese are advocating and planning for.
While many in the United States government see SBSP as a pipe dream, many other nations, friendly and otherwise, see our lack of initiative and vision as an opportunity to become the world leaders in space and seize its strategic effects for their countries’ economic, diplomatic, and military power worldwide. If the United States does not craft a similarly far-reaching national space strategy, it may be left in a situation where it cannot compete globally in the new markets of space resources and on-orbit energy applications. This could adversely affect US influence abroad and at home.
The National Space Society, in addition to the previously mentioned National Security Space Office report, has explored the security and economic benefits of SBSP in the last decade. Our friends in Japan and India are also exploring this potential opportunity. It’s time the US government examined the current strategic situation and proactively explored the development and deployment of SBSP as one step in our quest to push America out into the solar system for the development and “colonial expansion” of our society. Leadership in space should not be assumed: it requires hard, continued work to assure its existence into the future.
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Christopher Stone (B.A., M.A.) is a space policy analyst and strategist near Washington DC.
Wednesday, October 5, 2011
Monday, October 3, 2011
Creating near-term results in US human space exploration
From The Space Review: Creating near-term results in US human space exploration
Next January will see the eighth anniversary of President Bush’s announcement of the Vision for Space Exploration (VSE), which set the nation on a renewed course to send Americans to explore beyond Earth orbit.
Eight years: that’s about how long it took from John F. Kennedy’s lunar landing challenge in 1961 to the accomplishment of that goal in 1969. Yet, eight years after the 2004 VSE announcement—by a president, no less—we are hardly closer to venturing beyond low Earth orbit (LEO) with humans than we were when these goals were first announced.
The reasons for the lack of quicker progress are many, as are those who share the blame. But identifying either those reasons or their culprits isn’t what is most important. What is important, in our estimation, is to avoid the mistakes of the recent past and accelerating progress in order to capture public and political imaginations. More specifically, we believe it is necessary to find a way for human exploration beyond LEO to begin in this very decade.
Unfortunately, the just-announced Space Launch System (SLS)’s first crew flight date goal is 2021, ten years from now. And that’s the best case. We hope the noble goals and intended timetable set by lawmakers and NASA for SLS can be met, but we believe that 2021 for the first crewed flight is simply too distant to ensure exploration sustainability, and can therefore ultimately lead us away from the exploration actually intended.
Since accelerating SLS itself is not fiscally feasible, one is led to ask: What can be done? We believe the solution boils down to one word: Pragmatism. This means exchanging more perfect solutions for more practical ones by using existing systems, modified to the least extent practical, to accelerate the pace of exploration.
We therefore urge an approach that obtains near-term results—i.e., human exploration beyond LEO—as quickly and as pragmatically as possible. In an era when budgets are shrinking, as are both public and political attention spans, we believe this course is a must for human space exploration in the United States.
Specifically what does this course imply? It means two things:
1. Establishing a commercial crew capability to LEO and International Space Station as rapidly as possible, in order to expeditiously free up resources within the human spaceflight budget for exploration, rather than expensive Soyuz seats.
2. Using the savings accrued by adopting commercial crew to jump start human exploration beyond LEO before SLS is ready. This can be accomplished by developing orbital refueling for, and then human-rating, one or more existing rockets to carry out simple exploration missions—such as lunar/near Earth object flybys and orbiters—using the Multi-Purpose Crew Vehicle or other crewed spacecraft that can be ready by mid-decade.
Studies we—and others—have been involved in over the past 18 months have shown that this kind of pragmatic approach is feasible. We believe that as soon as actual human visits to nearby worlds begin, the public excitement, scientific results, and other benefits of this exploration strengthen the desire for more of it, sustaining both SLS itself and NASA’s exploration objectives set in the 2020s and beyond.
There is no need for us to begin political games. Nor is there a need for new mandates, visions, or elections. But we must find ways to provide nearer-term exploration.
So let’s accelerate and invigorate human space exploration with human missions launched before this decade is out. In doing so, the exploration community can achieve the sustainability that has eluded us so far, and show a nation and the world just how creative and productive Americans of this generation can be in human space exploration.
Alan Stern is a planetary scientist and aerospace consultant. He is NASA’s former Associate Administrator in charge of Science, and he serves as the chair of the Commercial Spaceflight Federation’s Suborbital Applications Researchers Group. Gerry Griffin is an aerospace engineer, an Apollo flight director, and the former Director of the Johnson Space Center. He also served as the Associate Administrator for External Relations and Assistant Administrator for Legislative Affairs at NASA Headquarters. A version of this essay appeared in the September 26 issue of Space News.
Next January will see the eighth anniversary of President Bush’s announcement of the Vision for Space Exploration (VSE), which set the nation on a renewed course to send Americans to explore beyond Earth orbit.
Eight years: that’s about how long it took from John F. Kennedy’s lunar landing challenge in 1961 to the accomplishment of that goal in 1969. Yet, eight years after the 2004 VSE announcement—by a president, no less—we are hardly closer to venturing beyond low Earth orbit (LEO) with humans than we were when these goals were first announced.
The reasons for the lack of quicker progress are many, as are those who share the blame. But identifying either those reasons or their culprits isn’t what is most important. What is important, in our estimation, is to avoid the mistakes of the recent past and accelerating progress in order to capture public and political imaginations. More specifically, we believe it is necessary to find a way for human exploration beyond LEO to begin in this very decade.
Unfortunately, the just-announced Space Launch System (SLS)’s first crew flight date goal is 2021, ten years from now. And that’s the best case. We hope the noble goals and intended timetable set by lawmakers and NASA for SLS can be met, but we believe that 2021 for the first crewed flight is simply too distant to ensure exploration sustainability, and can therefore ultimately lead us away from the exploration actually intended.
Since accelerating SLS itself is not fiscally feasible, one is led to ask: What can be done? We believe the solution boils down to one word: Pragmatism. This means exchanging more perfect solutions for more practical ones by using existing systems, modified to the least extent practical, to accelerate the pace of exploration.
We therefore urge an approach that obtains near-term results—i.e., human exploration beyond LEO—as quickly and as pragmatically as possible. In an era when budgets are shrinking, as are both public and political attention spans, we believe this course is a must for human space exploration in the United States.
Specifically what does this course imply? It means two things:
1. Establishing a commercial crew capability to LEO and International Space Station as rapidly as possible, in order to expeditiously free up resources within the human spaceflight budget for exploration, rather than expensive Soyuz seats.
2. Using the savings accrued by adopting commercial crew to jump start human exploration beyond LEO before SLS is ready. This can be accomplished by developing orbital refueling for, and then human-rating, one or more existing rockets to carry out simple exploration missions—such as lunar/near Earth object flybys and orbiters—using the Multi-Purpose Crew Vehicle or other crewed spacecraft that can be ready by mid-decade.
Studies we—and others—have been involved in over the past 18 months have shown that this kind of pragmatic approach is feasible. We believe that as soon as actual human visits to nearby worlds begin, the public excitement, scientific results, and other benefits of this exploration strengthen the desire for more of it, sustaining both SLS itself and NASA’s exploration objectives set in the 2020s and beyond.
There is no need for us to begin political games. Nor is there a need for new mandates, visions, or elections. But we must find ways to provide nearer-term exploration.
So let’s accelerate and invigorate human space exploration with human missions launched before this decade is out. In doing so, the exploration community can achieve the sustainability that has eluded us so far, and show a nation and the world just how creative and productive Americans of this generation can be in human space exploration.
Alan Stern is a planetary scientist and aerospace consultant. He is NASA’s former Associate Administrator in charge of Science, and he serves as the chair of the Commercial Spaceflight Federation’s Suborbital Applications Researchers Group. Gerry Griffin is an aerospace engineer, an Apollo flight director, and the former Director of the Johnson Space Center. He also served as the Associate Administrator for External Relations and Assistant Administrator for Legislative Affairs at NASA Headquarters. A version of this essay appeared in the September 26 issue of Space News.
International cooperation key to making space affordable - Nasa
From Engineering News.co.za: International cooperation key to making space affordable - Nasa
Keeping space projects affordable was currently the key challenge for the National Aeronautics and Space Administration (Nasa) and probably most other space agencies in the world, Nasa administrator Charles Bolden said at the International Astronautical Congress, in Cape Town, on Monday.
Addressing the gathering together with the heads of a number of international space agencies, Bolden said that while the US government remained supportive of the space programme, more value was being demanded for the money spent.
“The public sector is demanding that we produce affordable systems with very sound plans that are sustainable and that will last over multiple administrations in the United States,” said Bolden.
The only way to achieve this, in Bolden’s opinion, was through international cooperation. “It’s important for as many nations as possible to join in the exploration effort. No one nation is going to be able to do the things that we all want to do alone, so it’s very important for every nation to participate.”
He echoed these sentiments even when asked about whether China’s participation in the space sector is a threat to the US, though confirmed that Nasa was currently prohibited by law from being involved in bilateral relationships with China.
According to Bolden, cooperation would also be extended to commercial entities and he predicted that, within months, and not years, private companies would be carrying cargo to the International Space Station (ISS).
He said that already two companies, Orbital Sciences and SpaceX, were preparing to fly their final demonstration missions before they were cleared to deliver cargo to the ISS.
With Russia still being a dominant force in the space industry, having about 40% of all space launches, head of the Russian Federal Space Agency, Vladmir Popovkin, also confirmed that international cooperation was vital. “Current large space exploration programmes are unthinkable without broader international cooperation.”
Russia already had numerous cooperative programmes with many other countries for which it carried out space launches. But it has experienced some problems during the last year in meeting its obligations. “Some failures have shown us again that space activities are very technologically advanced and difficult activities, so we must be very accurate and work carefully during the preflight preparations phase and launch phase,” he said.
While Nasa, the Russian Federal Space Agency and the European Space Agency were still looking at programmes of space exploration, including manned missions to Mars, the focus of the Japan Aerospace Exploration Agency (Jaxa) had now turned to using its space programme for launching satellites for disaster management and environmental observation.
According to Jaxa President, Keiji Tachikawa, the importance of space exploration and international cooperation in this area became important in the aftermath of the March 11, 2011 earth quake and tsunami that rocked Japan. “Satellite images of the affected areas from many organisations through international cooperation frameworks . . . were critical for our countermeasures after the earthquake,” said Tachikawa.
Similarly, India was using its space programme for environmental efforts and as a developing country is especially looking at using its programme to promote societal benefits. One of India’s latest satellite projects, in which is involved in with Jaxa and Nasa, would be collecting data on cloud formation and precipitation in the tropics which should contribute to learning more about climate change.
The vice chairperson of the Indian Space Research Organisation, Ranganath Navalgund, said that it was intended that the data would become freely available to the international community after the initial phase of the project of approximately nine months.
“It will be very important to have this particular data set in terms of climate change as well as societal benefits of many of the countries along the tropics,” said Navalgund.
Keeping space projects affordable was currently the key challenge for the National Aeronautics and Space Administration (Nasa) and probably most other space agencies in the world, Nasa administrator Charles Bolden said at the International Astronautical Congress, in Cape Town, on Monday.
Addressing the gathering together with the heads of a number of international space agencies, Bolden said that while the US government remained supportive of the space programme, more value was being demanded for the money spent.
“The public sector is demanding that we produce affordable systems with very sound plans that are sustainable and that will last over multiple administrations in the United States,” said Bolden.
The only way to achieve this, in Bolden’s opinion, was through international cooperation. “It’s important for as many nations as possible to join in the exploration effort. No one nation is going to be able to do the things that we all want to do alone, so it’s very important for every nation to participate.”
He echoed these sentiments even when asked about whether China’s participation in the space sector is a threat to the US, though confirmed that Nasa was currently prohibited by law from being involved in bilateral relationships with China.
According to Bolden, cooperation would also be extended to commercial entities and he predicted that, within months, and not years, private companies would be carrying cargo to the International Space Station (ISS).
He said that already two companies, Orbital Sciences and SpaceX, were preparing to fly their final demonstration missions before they were cleared to deliver cargo to the ISS.
With Russia still being a dominant force in the space industry, having about 40% of all space launches, head of the Russian Federal Space Agency, Vladmir Popovkin, also confirmed that international cooperation was vital. “Current large space exploration programmes are unthinkable without broader international cooperation.”
Russia already had numerous cooperative programmes with many other countries for which it carried out space launches. But it has experienced some problems during the last year in meeting its obligations. “Some failures have shown us again that space activities are very technologically advanced and difficult activities, so we must be very accurate and work carefully during the preflight preparations phase and launch phase,” he said.
While Nasa, the Russian Federal Space Agency and the European Space Agency were still looking at programmes of space exploration, including manned missions to Mars, the focus of the Japan Aerospace Exploration Agency (Jaxa) had now turned to using its space programme for launching satellites for disaster management and environmental observation.
According to Jaxa President, Keiji Tachikawa, the importance of space exploration and international cooperation in this area became important in the aftermath of the March 11, 2011 earth quake and tsunami that rocked Japan. “Satellite images of the affected areas from many organisations through international cooperation frameworks . . . were critical for our countermeasures after the earthquake,” said Tachikawa.
Similarly, India was using its space programme for environmental efforts and as a developing country is especially looking at using its programme to promote societal benefits. One of India’s latest satellite projects, in which is involved in with Jaxa and Nasa, would be collecting data on cloud formation and precipitation in the tropics which should contribute to learning more about climate change.
The vice chairperson of the Indian Space Research Organisation, Ranganath Navalgund, said that it was intended that the data would become freely available to the international community after the initial phase of the project of approximately nine months.
“It will be very important to have this particular data set in terms of climate change as well as societal benefits of many of the countries along the tropics,” said Navalgund.
Saturday, October 1, 2011
The Planet Mars: An Overall History of Our Discoveries About that Planet
Dozens of spacecraft, including orbiters, landers, and rovers, have been sent to Mars by the Soviet Union, the United States, Europe, and Japan to study the planet's surface, climate, and geology. As of 2008, the price of transporting material from the surface of Earth to the surface of Mars is approximately US$309,000 per kilogram.
Active probes at the Martian system as of 2011 include the Mars Reconnaissance Orbiter (since 2006), Mars Express (since 2003), 2001 Mars Odyssey (since 2001), and on the surface, Opportunity Rover (since 2004). More recently concluded missions include Mars Global Surveyor (1997–2006) and Spirit Rover (2004–2010).
Roughly two-thirds of all spacecraft destined for Mars have failed in one manner or another before completing or even beginning their missions, including the difficult late 20th century period of early pioneers and first-timers.
In the 21st century failures are much less common. Mission failures are typically ascribed to technical problems, such as failed or lost communications or design errors, often due to inadequate funding or incompetence for a given mission.
Such failures have given rise to a satirical counter-culture blaming the failures on an Earth-Mars "Bermuda Triangle", a Mars "Curse", or the "Great Galactic Ghoul" that feeds on Martian spacecraft. Some of the latest failures include Beagle 2 (2003), Mars Climate Orbiter (1999), and Mars 96 (1996).
Past missions
The first successful fly-by of Mars was on July 14–15, 1965, by NASA's Mariner 4. On November 14, 1971 Mariner 9 became the first space probe to orbit another planet when it entered into orbit around Mars.
The first objects to successfully land on the surface were two Soviet probes: Mars 2 on November 27 and Mars 3 on December 2, 1971, but both ceased communicating within seconds of landing. The 1975 NASA launches of the Viking program consisted of two orbiters, each having a lander; both landers successfully touched down in 1976. Viking 1 remained operational for six years, Viking 2 for three. The Viking landers relayed color panoramas of Mars and the orbiters mapped the surface so well that the images remain in use.
The Soviet probes Phobos 1 and 2 were sent to Mars in 1988 to study Mars and its two moons. Phobos 1 lost contact on the way to Mars. Phobos 2, while successfully photographing Mars and Phobos, failed just before it was set to release two landers to the surface of Phobos.
Following the 1992 failure of the Mars Observer orbiter, the NASA Mars Global Surveyor achieved Mars orbit in 1997. This mission was a complete success, having finished its primary mapping mission in early 2001. Contact was lost with the probe in November 2006 during its third extended program, spending exactly 10 operational years in space. The NASA Mars Pathfinder, carrying a robotic exploration vehicle Sojourner, landed in the Ares Vallis on Mars in the summer of 1997, returning many images.
The NASA Phoenix Mars lander arrived on the north polar region of Mars on May 25, 2008. Its robotic arm was used to dig into the Martian soil and the presence of water ice was confirmed on June 20. The mission concluded on November 10, 2008 after contact was lost.
Current missions
The NASA Mars Odyssey orbiter entered Mars orbit in 2001. Odyssey's Gamma Ray Spectrometer detected significant amounts of hydrogen in the upper metre or so of regolith on Mars. This hydrogen is thought to be contained in large deposits of water ice.
The Mars Express mission of the European Space Agency (ESA) reached Mars in 2003. It carried the Beagle 2 lander, which failed during descent and was declared lost in February, 2004.
In early 2004 the Planetary Fourier Spectrometer team announced the orbiter had detected methane in the Martian atmosphere. ESA announced in June 2006 the discovery of aurorae on Mars.
In January 2004, the NASA twin Mars Exploration Rovers named Spirit (MER-A) and Opportunity (MER-B) landed on the surface of Mars. Both have met or exceeded all their targets. Among the most significant scientific returns has been conclusive evidence that liquid water existed at some time in the past at both landing sites. Martian dust devils and windstorms have occasionally cleaned both rovers' solar panels, and thus increased their lifespan.
On March 10, 2006, the NASA Mars Reconnaissance Orbiter (MRO) probe arrived in orbit to conduct a two-year science survey. The orbiter will map the Martian terrain and weather to find suitable landing sites for upcoming lander missions. The MRO snapped the first image of a series of active avalanches near the planet's north pole, scientists said March 3, 2008.
The Dawn spacecraft flew by Mars in February 2009 for a gravity assist on its way to investigate Vesta and then Ceres.
Future missions
The Mars Science Laboratory, named Curiosity, will be launched in 2011. It is a larger and more advanced version of the Mars Exploration Rovers, with a movement rate of 90 m/h. Experiments include a laser chemical sampler that can deduce the make-up of rocks at a distance of 13 m.
The joint Russian and Chinese Phobos-Grunt mission to return samples of the Martian moon, Phobos, is scheduled for launch in 2011. In 2008, NASA announced MAVEN, a robotic mission in 2013 to provide information about the atmosphere of Mars. In 2018 the ESA plans to launch its first Rover to Mars; the ExoMars rover will be capable of drilling 2 m into the soil in search of organic molecules.
The Finnish-Russian MetNet mission will land multiple small vehicles on Mars to establish a widespread observation network to investigate the planet's atmospheric structure, physics and meteorology. A precursor mission using one or a few landers is scheduled for launch in 2009 or 2011. One possibility is a piggyback launch on the Russian Phobos-Grunt mission.
Manned mission plans
The ESA hopes to land humans on Mars between 2030 and 2035. This will be preceded by successively larger probes, starting with the launch of the ExoMars probe and a joint NASA-ESA Mars sample return mission.
Manned exploration by the United States was identified as a long-term goal in the Vision for Space Exploration announced in 2004 by then US President George W. Bush. The planned Orion spacecraft would be used to send a human expedition to Earth's moon by 2020 as a stepping stone to a Mars expedition. On September 28, 2007, NASA administrator Michael D. Griffin stated that NASA aims to put a man on Mars by 2037.
Mars Direct, a low-cost human mission proposed by Robert Zubrin, founder of the Mars Society, would use heavy-lift Saturn V class rockets, such as the Space X Falcon X, or, the Ares V, to skip orbital construction, LEO rendezvous, and lunar fuel depots. A modified proposal, called "Mars to Stay", involves not returning the first immigrant explorers immediately, if ever (see Colonization of Mars).
Astronomy on Mars
With the existence of various orbiters, landers, and rovers, it is now possible to study astronomy from the Martian skies. While Mars’ moon Phobos appears about one third the angular diameter of the full Moon as it appears from Earth, Deimos appears more or less star-like, and appears only slightly brighter than Venus does from Earth.
There are also various phenomena well-known on Earth that have now been observed on Mars, such as meteors and auroras. A transit of the Earth as seen from Mars will occur on November 10, 2084.
There are also transits of Mercury and transits of Venus, and the moons Phobos and Deimos are of sufficiently small angular diameter that their partial "eclipses" of the Sun are best considered transits (see Transit of Deimos from Mars).
Viewing
Because the orbit of Mars is eccentric its apparent magnitude at opposition from the Sun can range from −3.0 to −1.4. The minimum brightness is magnitude +1.6 when the planet is in conjunction with the Sun.
Mars usually appears a distinct yellow, orange, or reddish color; the actual color of Mars is closer to butterscotch, and the redness seen is just dust in the planet's atmosphere; considering this NASA's Spirit rover has taken pictures of a greenish-brown, mud-colored landscape with blue-grey rocks and patches of light red colored sand.
When farthest away from the Earth, it is more than seven times as far from the latter as when it is closest. When least favorably positioned, it can be lost in the Sun's glare for months at a time. At its most favorable times—at 15- or 17-year intervals, and always between late July and late September—Mars shows a wealth of surface detail to a telescope. Especially noticeable, even at low magnification, are the polar ice caps.
As Mars approaches opposition it begins a period of retrograde motion, which means it will appear to move backwards in a looping motion with respect to the background stars. The duration of this retrograde motion lasts for about 72 days, and Mars reaches its peak luminosity in the middle of this motion.
Historical observations
The history of observations of Mars is marked by the oppositions of Mars, when the planet is closest to Earth and hence is most easily visible, which occur every couple of years. Even more notable are the perihelic oppositions of Mars which occur every 15 or 17 years, and are distinguished because Mars is close to perihelion, making it even closer to Earth.
The existence of Mars as a wandering object in the night sky was recorded by the ancient Egyptian astronomers and by 1534 BCE they were familiar with the retrograde motion of the planet. By the period of the Neo-Babylonian Empire, the Babylonian astronomers were making regular records of the positions of the planets and systematic observations of their behavior. For Mars, they knew that the planet made 37 synodic periods, or 42 circuits of the zodiac, every 79 years. They also invented arithmetic methods for making minor corrections to the predicted positions of the planets.
In the fourth century BCE, Aristotle noted that Mars disappeared behind the Moon during an occultation, indicating the planet was farther away. Ptolemy, a Greek living in Alexandria, attempted to address the problem of the orbital motion of Mars. Ptolemy's model and his collective work on astronomy was presented in the multi-volume collection Almagest, which became the authoritative treatise on Western astronomy for the next fourteen centuries.
Literature from ancient China confirms that Mars was known by Chinese astronomers by no later than the fourth century BCE. In the fifth century CE, the Indian astronomical text Surya Siddhanta estimated the diameter of Mars.
During the seventeenth century, Tycho Brahe measured the diurnal parallax of Mars that Johannes Kepler used to make a preliminary calculation of the relative distance to the planet. When the telescope became available, the diurnal parallax of Mars was again measured in an effort to determine the Sun-Earth distance. This was first performed by Giovanni Domenico Cassini in 1672. The early parallax measurements were hampered by the quality of the instruments.
The only occultation of Mars by Venus observed was that of October 13, 1590, seen by Michael Maestlin at Heidelberg. In 1610, Mars was viewed by Galileo Galilei, who was first to see it via telescope. The first person to draw a map of Mars that displayed any terrain features was the Dutch astronomer Christiaan Huygens.
Martian "canals"
By the 19th century, the resolution of telescopes reached a level sufficient for surface features to be identified. In September 1877, a perihelic opposition of Mars occurred on September 5. In that year, Italian astronomer Giovanni Schiaparelli used a 22 cm telescope in Milan to help produce the first detailed map of Mars. These maps notably contained features he called canali, which were later shown to be an optical illusion.
These canali were supposedly long straight lines on the surface of Mars to which he gave names of famous rivers on Earth. His term, which means "channels" or "grooves", was popularly mistranslated in English as "canals".
Influenced by the observations, the orientalist Percival Lowell founded an observatory which had a 300 and 450 mm telescope. The observatory was used for the exploration of Mars during the last good opportunity in 1894 and the following less favorable oppositions. He published several books on Mars and life on the planet, which had a great influence on the public. The canali were also found by other astronomers, like Henri Joseph Perrotin and Louis Thollon in Nice, using one of the largest telescopes of that time.
The seasonal changes (consisting of the diminishing of the polar caps and the dark areas formed during Martian summer) in combination with the canals lead to speculation about life on Mars, and it was a long held belief that Mars contained vast seas and vegetation. The telescope never reached the resolution required to give proof to any speculations. As bigger telescopes were used, fewer long, straight canali were observed. During an observation in 1909 by Flammarion with a 840 mm telescope, irregular patterns were observed, but no canali were seen.
Even in the 1960s articles were published on Martian biology, putting aside explanations other than life for the seasonal changes on Mars. Detailed scenarios for the metabolism and chemical cycles for a functional ecosystem have been published.
It was not until spacecraft visited the planet during NASA's Mariner missions in the 1960s that these myths were dispelled. The results of the Viking life-detection experiments started an intermission in which the hypothesis of a hostile, dead planet was generally accepted.
Some maps of Mars were made using the data from these missions, but it was not until the Mars Global Surveyor mission, launched in 1996 and operated until late 2006, that complete, extremely detailed maps of the martian topography, magnetic field and surface minerals were obtained. These maps are now available online, for example, at Google Mars.
Active probes at the Martian system as of 2011 include the Mars Reconnaissance Orbiter (since 2006), Mars Express (since 2003), 2001 Mars Odyssey (since 2001), and on the surface, Opportunity Rover (since 2004). More recently concluded missions include Mars Global Surveyor (1997–2006) and Spirit Rover (2004–2010).
Roughly two-thirds of all spacecraft destined for Mars have failed in one manner or another before completing or even beginning their missions, including the difficult late 20th century period of early pioneers and first-timers.
In the 21st century failures are much less common. Mission failures are typically ascribed to technical problems, such as failed or lost communications or design errors, often due to inadequate funding or incompetence for a given mission.
Such failures have given rise to a satirical counter-culture blaming the failures on an Earth-Mars "Bermuda Triangle", a Mars "Curse", or the "Great Galactic Ghoul" that feeds on Martian spacecraft. Some of the latest failures include Beagle 2 (2003), Mars Climate Orbiter (1999), and Mars 96 (1996).
Past missions
The first successful fly-by of Mars was on July 14–15, 1965, by NASA's Mariner 4. On November 14, 1971 Mariner 9 became the first space probe to orbit another planet when it entered into orbit around Mars.
The first objects to successfully land on the surface were two Soviet probes: Mars 2 on November 27 and Mars 3 on December 2, 1971, but both ceased communicating within seconds of landing. The 1975 NASA launches of the Viking program consisted of two orbiters, each having a lander; both landers successfully touched down in 1976. Viking 1 remained operational for six years, Viking 2 for three. The Viking landers relayed color panoramas of Mars and the orbiters mapped the surface so well that the images remain in use.
The Soviet probes Phobos 1 and 2 were sent to Mars in 1988 to study Mars and its two moons. Phobos 1 lost contact on the way to Mars. Phobos 2, while successfully photographing Mars and Phobos, failed just before it was set to release two landers to the surface of Phobos.
Following the 1992 failure of the Mars Observer orbiter, the NASA Mars Global Surveyor achieved Mars orbit in 1997. This mission was a complete success, having finished its primary mapping mission in early 2001. Contact was lost with the probe in November 2006 during its third extended program, spending exactly 10 operational years in space. The NASA Mars Pathfinder, carrying a robotic exploration vehicle Sojourner, landed in the Ares Vallis on Mars in the summer of 1997, returning many images.
The NASA Phoenix Mars lander arrived on the north polar region of Mars on May 25, 2008. Its robotic arm was used to dig into the Martian soil and the presence of water ice was confirmed on June 20. The mission concluded on November 10, 2008 after contact was lost.
Current missions
The NASA Mars Odyssey orbiter entered Mars orbit in 2001. Odyssey's Gamma Ray Spectrometer detected significant amounts of hydrogen in the upper metre or so of regolith on Mars. This hydrogen is thought to be contained in large deposits of water ice.
The Mars Express mission of the European Space Agency (ESA) reached Mars in 2003. It carried the Beagle 2 lander, which failed during descent and was declared lost in February, 2004.
In early 2004 the Planetary Fourier Spectrometer team announced the orbiter had detected methane in the Martian atmosphere. ESA announced in June 2006 the discovery of aurorae on Mars.
In January 2004, the NASA twin Mars Exploration Rovers named Spirit (MER-A) and Opportunity (MER-B) landed on the surface of Mars. Both have met or exceeded all their targets. Among the most significant scientific returns has been conclusive evidence that liquid water existed at some time in the past at both landing sites. Martian dust devils and windstorms have occasionally cleaned both rovers' solar panels, and thus increased their lifespan.
On March 10, 2006, the NASA Mars Reconnaissance Orbiter (MRO) probe arrived in orbit to conduct a two-year science survey. The orbiter will map the Martian terrain and weather to find suitable landing sites for upcoming lander missions. The MRO snapped the first image of a series of active avalanches near the planet's north pole, scientists said March 3, 2008.
The Dawn spacecraft flew by Mars in February 2009 for a gravity assist on its way to investigate Vesta and then Ceres.
Future missions
The Mars Science Laboratory, named Curiosity, will be launched in 2011. It is a larger and more advanced version of the Mars Exploration Rovers, with a movement rate of 90 m/h. Experiments include a laser chemical sampler that can deduce the make-up of rocks at a distance of 13 m.
The joint Russian and Chinese Phobos-Grunt mission to return samples of the Martian moon, Phobos, is scheduled for launch in 2011. In 2008, NASA announced MAVEN, a robotic mission in 2013 to provide information about the atmosphere of Mars. In 2018 the ESA plans to launch its first Rover to Mars; the ExoMars rover will be capable of drilling 2 m into the soil in search of organic molecules.
The Finnish-Russian MetNet mission will land multiple small vehicles on Mars to establish a widespread observation network to investigate the planet's atmospheric structure, physics and meteorology. A precursor mission using one or a few landers is scheduled for launch in 2009 or 2011. One possibility is a piggyback launch on the Russian Phobos-Grunt mission.
Manned mission plans
The ESA hopes to land humans on Mars between 2030 and 2035. This will be preceded by successively larger probes, starting with the launch of the ExoMars probe and a joint NASA-ESA Mars sample return mission.
Manned exploration by the United States was identified as a long-term goal in the Vision for Space Exploration announced in 2004 by then US President George W. Bush. The planned Orion spacecraft would be used to send a human expedition to Earth's moon by 2020 as a stepping stone to a Mars expedition. On September 28, 2007, NASA administrator Michael D. Griffin stated that NASA aims to put a man on Mars by 2037.
Mars Direct, a low-cost human mission proposed by Robert Zubrin, founder of the Mars Society, would use heavy-lift Saturn V class rockets, such as the Space X Falcon X, or, the Ares V, to skip orbital construction, LEO rendezvous, and lunar fuel depots. A modified proposal, called "Mars to Stay", involves not returning the first immigrant explorers immediately, if ever (see Colonization of Mars).
Astronomy on Mars
With the existence of various orbiters, landers, and rovers, it is now possible to study astronomy from the Martian skies. While Mars’ moon Phobos appears about one third the angular diameter of the full Moon as it appears from Earth, Deimos appears more or less star-like, and appears only slightly brighter than Venus does from Earth.
There are also various phenomena well-known on Earth that have now been observed on Mars, such as meteors and auroras. A transit of the Earth as seen from Mars will occur on November 10, 2084.
There are also transits of Mercury and transits of Venus, and the moons Phobos and Deimos are of sufficiently small angular diameter that their partial "eclipses" of the Sun are best considered transits (see Transit of Deimos from Mars).
Viewing
Because the orbit of Mars is eccentric its apparent magnitude at opposition from the Sun can range from −3.0 to −1.4. The minimum brightness is magnitude +1.6 when the planet is in conjunction with the Sun.
Mars usually appears a distinct yellow, orange, or reddish color; the actual color of Mars is closer to butterscotch, and the redness seen is just dust in the planet's atmosphere; considering this NASA's Spirit rover has taken pictures of a greenish-brown, mud-colored landscape with blue-grey rocks and patches of light red colored sand.
When farthest away from the Earth, it is more than seven times as far from the latter as when it is closest. When least favorably positioned, it can be lost in the Sun's glare for months at a time. At its most favorable times—at 15- or 17-year intervals, and always between late July and late September—Mars shows a wealth of surface detail to a telescope. Especially noticeable, even at low magnification, are the polar ice caps.
As Mars approaches opposition it begins a period of retrograde motion, which means it will appear to move backwards in a looping motion with respect to the background stars. The duration of this retrograde motion lasts for about 72 days, and Mars reaches its peak luminosity in the middle of this motion.
Historical observations
The history of observations of Mars is marked by the oppositions of Mars, when the planet is closest to Earth and hence is most easily visible, which occur every couple of years. Even more notable are the perihelic oppositions of Mars which occur every 15 or 17 years, and are distinguished because Mars is close to perihelion, making it even closer to Earth.
The existence of Mars as a wandering object in the night sky was recorded by the ancient Egyptian astronomers and by 1534 BCE they were familiar with the retrograde motion of the planet. By the period of the Neo-Babylonian Empire, the Babylonian astronomers were making regular records of the positions of the planets and systematic observations of their behavior. For Mars, they knew that the planet made 37 synodic periods, or 42 circuits of the zodiac, every 79 years. They also invented arithmetic methods for making minor corrections to the predicted positions of the planets.
In the fourth century BCE, Aristotle noted that Mars disappeared behind the Moon during an occultation, indicating the planet was farther away. Ptolemy, a Greek living in Alexandria, attempted to address the problem of the orbital motion of Mars. Ptolemy's model and his collective work on astronomy was presented in the multi-volume collection Almagest, which became the authoritative treatise on Western astronomy for the next fourteen centuries.
Literature from ancient China confirms that Mars was known by Chinese astronomers by no later than the fourth century BCE. In the fifth century CE, the Indian astronomical text Surya Siddhanta estimated the diameter of Mars.
During the seventeenth century, Tycho Brahe measured the diurnal parallax of Mars that Johannes Kepler used to make a preliminary calculation of the relative distance to the planet. When the telescope became available, the diurnal parallax of Mars was again measured in an effort to determine the Sun-Earth distance. This was first performed by Giovanni Domenico Cassini in 1672. The early parallax measurements were hampered by the quality of the instruments.
The only occultation of Mars by Venus observed was that of October 13, 1590, seen by Michael Maestlin at Heidelberg. In 1610, Mars was viewed by Galileo Galilei, who was first to see it via telescope. The first person to draw a map of Mars that displayed any terrain features was the Dutch astronomer Christiaan Huygens.
Martian "canals"
By the 19th century, the resolution of telescopes reached a level sufficient for surface features to be identified. In September 1877, a perihelic opposition of Mars occurred on September 5. In that year, Italian astronomer Giovanni Schiaparelli used a 22 cm telescope in Milan to help produce the first detailed map of Mars. These maps notably contained features he called canali, which were later shown to be an optical illusion.
These canali were supposedly long straight lines on the surface of Mars to which he gave names of famous rivers on Earth. His term, which means "channels" or "grooves", was popularly mistranslated in English as "canals".
Influenced by the observations, the orientalist Percival Lowell founded an observatory which had a 300 and 450 mm telescope. The observatory was used for the exploration of Mars during the last good opportunity in 1894 and the following less favorable oppositions. He published several books on Mars and life on the planet, which had a great influence on the public. The canali were also found by other astronomers, like Henri Joseph Perrotin and Louis Thollon in Nice, using one of the largest telescopes of that time.
The seasonal changes (consisting of the diminishing of the polar caps and the dark areas formed during Martian summer) in combination with the canals lead to speculation about life on Mars, and it was a long held belief that Mars contained vast seas and vegetation. The telescope never reached the resolution required to give proof to any speculations. As bigger telescopes were used, fewer long, straight canali were observed. During an observation in 1909 by Flammarion with a 840 mm telescope, irregular patterns were observed, but no canali were seen.
Even in the 1960s articles were published on Martian biology, putting aside explanations other than life for the seasonal changes on Mars. Detailed scenarios for the metabolism and chemical cycles for a functional ecosystem have been published.
It was not until spacecraft visited the planet during NASA's Mariner missions in the 1960s that these myths were dispelled. The results of the Viking life-detection experiments started an intermission in which the hypothesis of a hostile, dead planet was generally accepted.
Some maps of Mars were made using the data from these missions, but it was not until the Mars Global Surveyor mission, launched in 1996 and operated until late 2006, that complete, extremely detailed maps of the martian topography, magnetic field and surface minerals were obtained. These maps are now available online, for example, at Google Mars.
Friday, September 30, 2011
Reusable Spacecraft Key For Human Space Exploration
From Talk Radio News: Reusable Spacecraft Key For Human Space Exploration
SpaceX Founder and CEO Elon Musk addressed a small audience at the National Press Club Thursday to offer his expertise on the future of human space flight exploration.
In the attempt to make the human race a multi-planetary species, Musk said SpaceX has created some of the world’s most reliable and economical launch vehicles and spacecraft. Some, including the Falcon 9 rocket and the Dragon, have gained high global recognition for abilities such as carrying payloads to space at 30-50 percent of the cost of its competitors.
“The pivotal breakthrough that’s necessary, that some company has to come up with to make life multi-planetary, is a fully and rapidly reusable forward-class rocket,” Musk said. The Dragon, he said, fits this description.
The Dragon is SpaceX’s fully reusable spacecraft and is set to launch to the International Space Station on November 3. During that mission the company will be monitoring the reusability for future launches. However, Musk said the company is aware of the various engineering problems, such as spacecraft weight accuracy and engine efficiency.
“If your rocket ends up being just a little bit heavier, you get nothing to orbit,” he said. However, he said, this is a risk the company is willing to take to create for the future of human space flight.
“SpaceX is going to try to do it. We could fail; I’m not saying we have certain success here but we are gonna try to do it,” Musk said.
Musk said SpaceX has been working hard in creating a reusable spacecraft and said it is the key to dramatic cost savings enabling innovative U.S. space exploration programs.
Elon Musk is also the co-founder of Paypal, which he sold to Ebay in 2002 for $1.5 billion which allowed him to start SpaceX.
SpaceX Founder and CEO Elon Musk addressed a small audience at the National Press Club Thursday to offer his expertise on the future of human space flight exploration.
In the attempt to make the human race a multi-planetary species, Musk said SpaceX has created some of the world’s most reliable and economical launch vehicles and spacecraft. Some, including the Falcon 9 rocket and the Dragon, have gained high global recognition for abilities such as carrying payloads to space at 30-50 percent of the cost of its competitors.
“The pivotal breakthrough that’s necessary, that some company has to come up with to make life multi-planetary, is a fully and rapidly reusable forward-class rocket,” Musk said. The Dragon, he said, fits this description.
The Dragon is SpaceX’s fully reusable spacecraft and is set to launch to the International Space Station on November 3. During that mission the company will be monitoring the reusability for future launches. However, Musk said the company is aware of the various engineering problems, such as spacecraft weight accuracy and engine efficiency.
“If your rocket ends up being just a little bit heavier, you get nothing to orbit,” he said. However, he said, this is a risk the company is willing to take to create for the future of human space flight.
“SpaceX is going to try to do it. We could fail; I’m not saying we have certain success here but we are gonna try to do it,” Musk said.
Musk said SpaceX has been working hard in creating a reusable spacecraft and said it is the key to dramatic cost savings enabling innovative U.S. space exploration programs.
Elon Musk is also the co-founder of Paypal, which he sold to Ebay in 2002 for $1.5 billion which allowed him to start SpaceX.
China’s space station: A new era of space exploration
From SmartPlanet.com: China’s space station: A new era of space exploration?
With the retirement of NASA’s space shuttles and Russia announcing plans to eventually sink the International Space Station, 2011 hasn’t exactly shaped up to be a banner year for space exploration. But don’t tell that to China, where the feeling is far from mutual.
On Thursday evening, the unmanned Tiangong-1 space lab launched into orbit aboard a Chinese Long March 2F rocket, a monumental milestone for an ascending superpower embarking on it’s own golden age of space exploration. The move is part of the China National Space Administration’s bold vision to put into operation a 60-ton space station in orbit by 2020. In the next phase, officials will launch in 2013 the Tiangong-2, a module equipped to provide three astronauts with a livable environment for about 20 days. Tiangong-3, scheduled for 2015, will enable to the astronauts to stay on-board for about twice as long, during which time they’ll conduct experiments to test regenerative life-support technology and other space survival projects.
* Related: China to launch lunar rover, mine moon for nuclear fuel
While flipping the lights on aboard a fully-functional space station would be an impressive accomplishment for a nation that only eight years ago sent their first astronauts into space, officials would still consider it merely a stepping stone towards much more ambitious goals, such as colonizing the moon and, perhaps, even a manned mission to Mars. But before the fledgling space program can even begin dreaming about setting foot on other planets, scientists need to show that they’re up to task technologically. At this point, it means demonstrating that their Shenzhou space capsule is capable of successfully docking the space lab.
“It’s a big deal at several levels,” said Dean Cheng, a research fellow at the conservative Heritage Foundation told Space.com. “If all goes according to plan this will be China’s initial effort at docking, and of course docking is one of those sin qua nons for more prolonged exploration of space. They have to get this skill set down.”
China is gearing up the Shenzhou spacecraft for three upcoming flights in which it will connect with the Tiangong 1 module. First up is the Shenzhou 8 mission, scheduled to launch in November, followed by Shenzhou 9 the following year. Both trips will be unmanned missions and serve as docking trials in preparation for Shenzhou 10, a potentially manned journey that’s expected to be notable in more than one way since it may include the country’s first female astronaut.
Though the Chinese have completed three manned missions using the capsule, it has never met the type of stringent standards that would have enabled it to dock with the International Space Station. The Space Review’s Dwayne A. Day sheds some light on the often-complicated relations between the U.S. and china and why NASA considers the Shenzhou technology to be unproven:
For starters, the United States has limited knowledge of and therefore no confidence in the Chinese manned spacecraft. To date, Shenzhou has flown only twice with humans aboard. The second flight took place two years after the first, and the third, scheduled for this year, will be three years after the second. It is doubtful that the Chinese themselves can have much understanding and confidence in the vehicle considering how rarely they actually fly it. If they were moving any slower, they’d be going backward. Each new flight accomplishes more than the last, but they may be losing experience they have gained—you can climb stairs with less steps if take them three at a time, but you also run the risk of falling and breaking your neck.
Despite such doubts, China has shown it has no qualms about going its own way and the successful launch of Tiangong-1 should set the stage for what will be — at the very least — a defining year.
Tuesday, September 27, 2011
The planet Venus: A Brief Overvall View of our Accumulation of Knowledge
Studies
Early studies
The Venus tablet of Ammisaduqa, dated 1581 BC, records the observations of Babylonian astrologers. It refers to Venus as Nin-dar-an-na, or "bright queen of the sky".Venus was known to ancient civilizations both as the "morning star" and as the "evening star", names that reflect the early understanding that these were two separate objects. The Venus tablet of Ammisaduqa, dated 1581 BC, shows that the Babylonians understood that the two were a single object, referred to in the tablet as the "bright queen of the sky," and could support this view with detailed observations.
The Greeks thought of the two as separate stars, Phosphorus and Hesperus, until the time of Pythagoras in the sixth century BC. The Romans designated the morning aspect of Venus as Lucifer, literally "Light-Bringer", and the evening aspect as Vesper.
The transit of Venus was first observed in 1032 by the Persian astronomer Avicenna, who concluded that Venus is closer to the Earth than the Sun, and established that Venus was, at least sometimes, below the Sun. In the 12th century, the Andalusian astronomer Ibn Bajjah observed "two planets as black spots on the face of the Sun," which was later identified as the transit of Venus and Mercury by the Maragha astronomer Qotb al-Din Shirazi in the 13th century.
17th Century
When the Italian physicist Galileo Galilei first observed the planet in the early 17th century, he found that it showed phases like the Moon, varying from crescent to gibbous to full and vice versa. When Venus is furthest from the Sun in the sky it shows a half-lit phase and when it is closest to the Sun in the sky it shows as a crescent or full phase. This could be possible only if Venus orbited the Sun, and this was among the first observations to clearly contradict the Ptolemaic geocentric model that the Solar System was concentric and centered on the Earth.
The atmosphere of Venus was discovered in 1761 by Russian polymath Mikhail Lomonosov. Venus' atmosphere was observed in 1790 by German astronomer Johann Schröter. Schröter found that when the planet was a thin crescent, the cusps extended through more than 180°. He correctly surmised that this was due to scattering of sunlight in a dense atmosphere. Later, American astronomer Chester Smith Lyman observed a complete ring around the dark side of the planet when it was at inferior conjunction, providing further evidence for an atmosphere.
The atmosphere complicated efforts to determine a rotation period for the planet, and observers such as Italian-born astronomer Giovanni Cassini and Schröter incorrectly estimated periods of about 24 hours from the motions of markings on the planet's apparent surface.
Ground-based research
Little more was discovered about Venus until the 20th century. Its almost featureless disc gave no hint what its surface might be like, and it was only with the development of spectroscopic, radar and ultraviolet observations that more of its secrets were revealed. The first UV observations were carried out in the 1920s, when Frank E. Ross found that UV photographs revealed considerable detail that was absent in visible and infrared radiation. He suggested that this was due to a very dense yellow lower atmosphere with high cirrus clouds above it.
Spectroscopic observations in the 1900s gave the first clues about the Venusian rotation. Vesto Slipher tried to measure the Doppler shift of light from Venus, but found that he could not detect any rotation. He surmised that the planet must have a much longer rotation period than had previously been thought. Later work in the 1950s showed that the rotation was retrograde. Radar observations of Venus were first carried out in the 1960s, and provided the first measurements of the rotation period which were close to the modern value.
Radar observations in the 1970s revealed details of the Venusian surface for the first time. Pulses of radio waves were beamed at the planet using the 300 m radio telescope at Arecibo Observatory, and the echoes revealed two highly reflective regions, designated the Alpha and Beta regions. The observations also revealed a bright region attributed to mountains, which was called Maxwell Montes. These three features are now the only ones on Venus which do not have female names.
Exploration
Early efforts
Mariner 2, launched in 1962The first robotic space probe mission to Venus, and the first to any planet, began on February 12, 1961 with the launch of the Venera 1 probe. The first craft of the otherwise highly successful Soviet Venera program, Venera 1 was launched on a direct impact trajectory, but contact was lost seven days into the mission, when the probe was about 2 million km from Earth. It was estimated to have passed within 100,000 km from Venus in mid-May.
The United States exploration of Venus also started badly with the loss of the Mariner 1 probe on launch. The subsequent Mariner 2 mission enjoyed greater success, and after a 109-day transfer orbit on December 14, 1962 it became the world's first successful interplanetary mission, passing 34,833 km above the surface of Venus. Its microwave and infrared radiometers revealed that while the Venusian cloud tops were cool, the surface was extremely hot—at least 425 °C, finally ending any hopes that the planet might harbor ground-based life. Mariner 2 also obtained improved estimates of its mass and of the astronomical unit, but was unable to detect either a magnetic field or radiation belts.
Atmospheric entry
The Soviet Venera 3 probe crash-landed on Venus on March 1, 1966. It was the first man-made object to enter the atmosphere and strike the surface of another planet, though its communication system failed before it was able to return any planetary data.
Venus's next encounter with an unmanned probe came on October 18, 1967 when Venera 4 successfully entered the atmosphere and deployed a number of science experiments. Venera 4 showed that the surface temperature was even hotter than Mariner 2 had measured at almost 500 °C, and that the atmosphere was about 90 to 95% carbon dioxide. The Venusian atmosphere was considerably denser than Venera 4's designers had anticipated, and its slower than intended parachute descent meant that its batteries ran down before the probe reached the surface. After returning descent data for 93 minutes, Venera 4's last pressure reading was 18 bar at an altitude of 24.96 km.[90]
Another probe arrived at Venus one day later on October 19, 1967 when Mariner 5 conducted a flyby at a distance of less than 4000 km above the cloud tops. Mariner 5 was originally built as backup for the Mars-bound Mariner 4, but when that mission was successful, the probe was refitted for a Venus mission. A suite of instruments more sensitive than those on Mariner 2, in particular its radio occultation experiment, returned data on the composition, pressure and density of the Venusian atmosphere.
The joint Venera 4–Mariner 5 data were analyzed by a combined Soviet-American science team in a series of colloquia over the following year, in an early example of space cooperation.[93]
Armed with the lessons and data learned from Venera 4, the Soviet Union launched the twin probes Venera 5 and Venera 6 five days apart in January 1969; they encountered Venus a day apart on May 16 and May 17 that year. The probes were strengthened to improve their crush depth to 25 bar and were equipped with smaller parachutes to achieve a faster descent. Since then-current atmospheric models of Venus suggested a surface pressure of between 75 and 100 bar, neither was expected to survive to the surface. After returning atmospheric data for a little over fifty minutes, they both were crushed at altitudes of approximately 20 km before going on to strike the surface on the night side of Venus.
Surface and atmospheric science
Venera 7 represented an effort to return data from the planet's surface, and was constructed with a reinforced descent module capable of withstanding a pressure of 180 bar. The module was pre-cooled before entry and equipped with a specially reefed parachute for a rapid 35-minute descent.
Entering the atmosphere on December 15, 1970, the parachute is believed to have partially torn during the descent, and the probe struck the surface with a hard, yet not fatal, impact. Probably tilted onto its side, it returned a weak signal supplying temperature data for 23 minutes, the first telemetry received from the surface of another planet.
The Venera program continued with Venera 8 sending data from the surface for 50 minutes, after entering the atmosphere on July 22, 1972. Venera 9, which entered the atmosphere of Venus on October 22, 1975, and Venera 10, which entered the atmosphere three days later on October 25, sent the first images of the Venusian landscape.
The two landing sites presented very different terrain in the immediate vicinities of the landers: Venera 9 had landed on a 20 degree slope scattered with boulders around 30–40 cm across; Venera 10 showed basalt-like rock slabs interspersed with weathered material.
In the meantime, the United States had sent the Mariner 10 probe on a gravitational slingshot trajectory past Venus on its way to Mercury. On February 5, 1974, Mariner 10 passed within 5790 km of Venus, returning over 4000 photographs as it did so. The images, the best then achieved, showed the planet to be almost featureless in visible light, but ultraviolet light revealed details in the clouds that had never been seen in Earth-bound observations.
The American Pioneer Venus project consisted of two separate missions. The Pioneer Venus Orbiter was inserted into an elliptical orbit around Venus on December 4, 1978, and remained there for over thirteen years studying the atmosphere and mapping the surface with radar. The Pioneer Venus Multiprobe released a total of four probes which entered the atmosphere on December 9, 1978, returning data on its composition, winds and heat fluxes.
Four more Venera lander missions took place over the next four years, with Venera 11 and Venera 12 detecting Venusian electrical storms;[98] and Venera 13 and Venera 14, landing four days apart on March 1 and March 5, 1982, returning the first color photographs of the surface. All four missions deployed parachutes for braking in the upper atmosphere, but released them at altitudes of 50 km, the dense lower atmosphere providing enough friction to allow for an unaided soft landing.
Both Venera 13 and 14 analyzed soil samples with an on-board X-ray fluorescence spectrometer, and attempted to measure the compressibility of the soil with an impact probe.[98] Venera 14, though, had the misfortune to strike its own ejected camera lens cap and its probe failed to contact the soil.
The Venera program came to a close in October 1983 when Venera 15 and Venera 16 were placed in orbit to conduct mapping of the Venusian terrain with synthetic aperture radar.
In 1985 the Soviet Union took advantage of the opportunity to combine missions to Venus and Comet Halley, which passed through the inner Solar System that year. En route to Halley, on June 11 and June 15, 1985 the two spacecraft of the Vega program each dropped a Venera-style probe (of which Vega 1's partially failed) and released a balloon-supported aerobot into the upper atmosphere. The balloons achieved an equilibrium altitude of around 53 km, where pressure and temperature are comparable to those at Earth's surface. They remained operational for around 46 hours, and discovered that the Venusian atmosphere was more turbulent than previously believed, and subject to high winds and powerful convection cells.
Radar mapping
The United States' Magellan probe was launched on May 4, 1989 with a mission to map the surface of Venus with radar. The high-resolution images it obtained during its 4½ years of operation far surpassed all prior maps and were comparable to visible-light photographs of other planets. Magellan imaged over 98% of the Venusian surface by radar and mapped 95% of its gravity field. In 1994, at the end of its mission, Magellan was deliberately sent to its destruction into the atmosphere of Venus to quantify its density.[103] Venus was observed by the Galileo and Cassini spacecraft during flybys on their respective missions to the outer planets, but Magellan would otherwise be the last dedicated mission to Venus for over a decade.
Current and future missions
NASA's MESSENGER mission to Mercury performed two flybys of Venus in October 2006 and June 2007, to slow its trajectory for an eventual orbital insertion of Mercury in March 2011. MESSENGER collected scientific data on both those flybys.[106]
The Venus Express probe was designed and built by the European Space Agency. Launched on November 9, 2005 by a Russian Soyuz-Fregat rocket procured through Starsem, it successfully assumed a polar orbit around Venus on April 11, 2006.
The probe is undertaking a detailed study of the Venusian atmosphere and clouds, including mapping of the planet's plasma environment and surface characteristics, particularly temperatures. One of the first results emerging from Venus Express is the discovery that a huge double atmospheric vortex exists at the south pole of the planet.
The Japan Aerospace Exploration Agency (JAXA) devised a Venus orbiter, Akatsuki (formerly "Planet-C"), which was launched on May 20, 2010 but the craft failed to enter orbit in December 2010. Hopes remain that the probe can successfully hibernate and make another insertion attempt in six years. Planned investigations included surface imaging with an infrared camera and experiments designed to confirm the presence of lightning as well as the determination of the existence of current surface volcanism.
The European Space Agency (ESA) hopes to launch a mission to Mercury in 2014, called BepiColombo, which will perform two flybys of Venus before it reaches Mercury orbit in 2020.
Under its New Frontiers Program, NASA has proposed a lander mission called the Venus In-Situ Explorer to land on Venus to study surface conditions and investigate the elemental and mineralogical features of the regolith. The probe would be equipped with a core sampler to drill into the surface and study pristine rock samples not weathered by the very harsh surface conditions. The Venera-D probe is a proposed Russian space probe to Venus, to be launched around 2016 with its goal to make remote-sensing observations around the planet Venus and deploying a lander, based on the Venera design, capable of surviving for a long duration on the planet's surface. Other proposed Venus exploration concepts include rovers, balloons, and airplanes.
NASA has recommended the Surface and Atmosphere Geochemical Explorer (SAGE) candidate mission to land on Venus, with a possible launch in 2016.
Manned flyby
A manned Venus flyby mission, using Apollo program hardware, was proposed in the late 1960s. The mission was planned to launch in late October or early November 1973, and would have used a Saturn V to send three men to fly past Venus in a flight lasting approximately one year. The spacecraft would have passed approximately 5,000 kilometres from the surface of Venus about four months later.
Early studies
The Venus tablet of Ammisaduqa, dated 1581 BC, records the observations of Babylonian astrologers. It refers to Venus as Nin-dar-an-na, or "bright queen of the sky".Venus was known to ancient civilizations both as the "morning star" and as the "evening star", names that reflect the early understanding that these were two separate objects. The Venus tablet of Ammisaduqa, dated 1581 BC, shows that the Babylonians understood that the two were a single object, referred to in the tablet as the "bright queen of the sky," and could support this view with detailed observations.
The Greeks thought of the two as separate stars, Phosphorus and Hesperus, until the time of Pythagoras in the sixth century BC. The Romans designated the morning aspect of Venus as Lucifer, literally "Light-Bringer", and the evening aspect as Vesper.
The transit of Venus was first observed in 1032 by the Persian astronomer Avicenna, who concluded that Venus is closer to the Earth than the Sun, and established that Venus was, at least sometimes, below the Sun. In the 12th century, the Andalusian astronomer Ibn Bajjah observed "two planets as black spots on the face of the Sun," which was later identified as the transit of Venus and Mercury by the Maragha astronomer Qotb al-Din Shirazi in the 13th century.
17th Century
When the Italian physicist Galileo Galilei first observed the planet in the early 17th century, he found that it showed phases like the Moon, varying from crescent to gibbous to full and vice versa. When Venus is furthest from the Sun in the sky it shows a half-lit phase and when it is closest to the Sun in the sky it shows as a crescent or full phase. This could be possible only if Venus orbited the Sun, and this was among the first observations to clearly contradict the Ptolemaic geocentric model that the Solar System was concentric and centered on the Earth.
The atmosphere of Venus was discovered in 1761 by Russian polymath Mikhail Lomonosov. Venus' atmosphere was observed in 1790 by German astronomer Johann Schröter. Schröter found that when the planet was a thin crescent, the cusps extended through more than 180°. He correctly surmised that this was due to scattering of sunlight in a dense atmosphere. Later, American astronomer Chester Smith Lyman observed a complete ring around the dark side of the planet when it was at inferior conjunction, providing further evidence for an atmosphere.
The atmosphere complicated efforts to determine a rotation period for the planet, and observers such as Italian-born astronomer Giovanni Cassini and Schröter incorrectly estimated periods of about 24 hours from the motions of markings on the planet's apparent surface.
Ground-based research
Little more was discovered about Venus until the 20th century. Its almost featureless disc gave no hint what its surface might be like, and it was only with the development of spectroscopic, radar and ultraviolet observations that more of its secrets were revealed. The first UV observations were carried out in the 1920s, when Frank E. Ross found that UV photographs revealed considerable detail that was absent in visible and infrared radiation. He suggested that this was due to a very dense yellow lower atmosphere with high cirrus clouds above it.
Spectroscopic observations in the 1900s gave the first clues about the Venusian rotation. Vesto Slipher tried to measure the Doppler shift of light from Venus, but found that he could not detect any rotation. He surmised that the planet must have a much longer rotation period than had previously been thought. Later work in the 1950s showed that the rotation was retrograde. Radar observations of Venus were first carried out in the 1960s, and provided the first measurements of the rotation period which were close to the modern value.
Radar observations in the 1970s revealed details of the Venusian surface for the first time. Pulses of radio waves were beamed at the planet using the 300 m radio telescope at Arecibo Observatory, and the echoes revealed two highly reflective regions, designated the Alpha and Beta regions. The observations also revealed a bright region attributed to mountains, which was called Maxwell Montes. These three features are now the only ones on Venus which do not have female names.
Exploration
Early efforts
Mariner 2, launched in 1962The first robotic space probe mission to Venus, and the first to any planet, began on February 12, 1961 with the launch of the Venera 1 probe. The first craft of the otherwise highly successful Soviet Venera program, Venera 1 was launched on a direct impact trajectory, but contact was lost seven days into the mission, when the probe was about 2 million km from Earth. It was estimated to have passed within 100,000 km from Venus in mid-May.
The United States exploration of Venus also started badly with the loss of the Mariner 1 probe on launch. The subsequent Mariner 2 mission enjoyed greater success, and after a 109-day transfer orbit on December 14, 1962 it became the world's first successful interplanetary mission, passing 34,833 km above the surface of Venus. Its microwave and infrared radiometers revealed that while the Venusian cloud tops were cool, the surface was extremely hot—at least 425 °C, finally ending any hopes that the planet might harbor ground-based life. Mariner 2 also obtained improved estimates of its mass and of the astronomical unit, but was unable to detect either a magnetic field or radiation belts.
Atmospheric entry
The Soviet Venera 3 probe crash-landed on Venus on March 1, 1966. It was the first man-made object to enter the atmosphere and strike the surface of another planet, though its communication system failed before it was able to return any planetary data.
Venus's next encounter with an unmanned probe came on October 18, 1967 when Venera 4 successfully entered the atmosphere and deployed a number of science experiments. Venera 4 showed that the surface temperature was even hotter than Mariner 2 had measured at almost 500 °C, and that the atmosphere was about 90 to 95% carbon dioxide. The Venusian atmosphere was considerably denser than Venera 4's designers had anticipated, and its slower than intended parachute descent meant that its batteries ran down before the probe reached the surface. After returning descent data for 93 minutes, Venera 4's last pressure reading was 18 bar at an altitude of 24.96 km.[90]
Another probe arrived at Venus one day later on October 19, 1967 when Mariner 5 conducted a flyby at a distance of less than 4000 km above the cloud tops. Mariner 5 was originally built as backup for the Mars-bound Mariner 4, but when that mission was successful, the probe was refitted for a Venus mission. A suite of instruments more sensitive than those on Mariner 2, in particular its radio occultation experiment, returned data on the composition, pressure and density of the Venusian atmosphere.
The joint Venera 4–Mariner 5 data were analyzed by a combined Soviet-American science team in a series of colloquia over the following year, in an early example of space cooperation.[93]
Armed with the lessons and data learned from Venera 4, the Soviet Union launched the twin probes Venera 5 and Venera 6 five days apart in January 1969; they encountered Venus a day apart on May 16 and May 17 that year. The probes were strengthened to improve their crush depth to 25 bar and were equipped with smaller parachutes to achieve a faster descent. Since then-current atmospheric models of Venus suggested a surface pressure of between 75 and 100 bar, neither was expected to survive to the surface. After returning atmospheric data for a little over fifty minutes, they both were crushed at altitudes of approximately 20 km before going on to strike the surface on the night side of Venus.
Surface and atmospheric science
Venera 7 represented an effort to return data from the planet's surface, and was constructed with a reinforced descent module capable of withstanding a pressure of 180 bar. The module was pre-cooled before entry and equipped with a specially reefed parachute for a rapid 35-minute descent.
Entering the atmosphere on December 15, 1970, the parachute is believed to have partially torn during the descent, and the probe struck the surface with a hard, yet not fatal, impact. Probably tilted onto its side, it returned a weak signal supplying temperature data for 23 minutes, the first telemetry received from the surface of another planet.
The Venera program continued with Venera 8 sending data from the surface for 50 minutes, after entering the atmosphere on July 22, 1972. Venera 9, which entered the atmosphere of Venus on October 22, 1975, and Venera 10, which entered the atmosphere three days later on October 25, sent the first images of the Venusian landscape.
The two landing sites presented very different terrain in the immediate vicinities of the landers: Venera 9 had landed on a 20 degree slope scattered with boulders around 30–40 cm across; Venera 10 showed basalt-like rock slabs interspersed with weathered material.
In the meantime, the United States had sent the Mariner 10 probe on a gravitational slingshot trajectory past Venus on its way to Mercury. On February 5, 1974, Mariner 10 passed within 5790 km of Venus, returning over 4000 photographs as it did so. The images, the best then achieved, showed the planet to be almost featureless in visible light, but ultraviolet light revealed details in the clouds that had never been seen in Earth-bound observations.
The American Pioneer Venus project consisted of two separate missions. The Pioneer Venus Orbiter was inserted into an elliptical orbit around Venus on December 4, 1978, and remained there for over thirteen years studying the atmosphere and mapping the surface with radar. The Pioneer Venus Multiprobe released a total of four probes which entered the atmosphere on December 9, 1978, returning data on its composition, winds and heat fluxes.
Four more Venera lander missions took place over the next four years, with Venera 11 and Venera 12 detecting Venusian electrical storms;[98] and Venera 13 and Venera 14, landing four days apart on March 1 and March 5, 1982, returning the first color photographs of the surface. All four missions deployed parachutes for braking in the upper atmosphere, but released them at altitudes of 50 km, the dense lower atmosphere providing enough friction to allow for an unaided soft landing.
Both Venera 13 and 14 analyzed soil samples with an on-board X-ray fluorescence spectrometer, and attempted to measure the compressibility of the soil with an impact probe.[98] Venera 14, though, had the misfortune to strike its own ejected camera lens cap and its probe failed to contact the soil.
The Venera program came to a close in October 1983 when Venera 15 and Venera 16 were placed in orbit to conduct mapping of the Venusian terrain with synthetic aperture radar.
In 1985 the Soviet Union took advantage of the opportunity to combine missions to Venus and Comet Halley, which passed through the inner Solar System that year. En route to Halley, on June 11 and June 15, 1985 the two spacecraft of the Vega program each dropped a Venera-style probe (of which Vega 1's partially failed) and released a balloon-supported aerobot into the upper atmosphere. The balloons achieved an equilibrium altitude of around 53 km, where pressure and temperature are comparable to those at Earth's surface. They remained operational for around 46 hours, and discovered that the Venusian atmosphere was more turbulent than previously believed, and subject to high winds and powerful convection cells.
Radar mapping
The United States' Magellan probe was launched on May 4, 1989 with a mission to map the surface of Venus with radar. The high-resolution images it obtained during its 4½ years of operation far surpassed all prior maps and were comparable to visible-light photographs of other planets. Magellan imaged over 98% of the Venusian surface by radar and mapped 95% of its gravity field. In 1994, at the end of its mission, Magellan was deliberately sent to its destruction into the atmosphere of Venus to quantify its density.[103] Venus was observed by the Galileo and Cassini spacecraft during flybys on their respective missions to the outer planets, but Magellan would otherwise be the last dedicated mission to Venus for over a decade.
Current and future missions
NASA's MESSENGER mission to Mercury performed two flybys of Venus in October 2006 and June 2007, to slow its trajectory for an eventual orbital insertion of Mercury in March 2011. MESSENGER collected scientific data on both those flybys.[106]
The Venus Express probe was designed and built by the European Space Agency. Launched on November 9, 2005 by a Russian Soyuz-Fregat rocket procured through Starsem, it successfully assumed a polar orbit around Venus on April 11, 2006.
The probe is undertaking a detailed study of the Venusian atmosphere and clouds, including mapping of the planet's plasma environment and surface characteristics, particularly temperatures. One of the first results emerging from Venus Express is the discovery that a huge double atmospheric vortex exists at the south pole of the planet.
The Japan Aerospace Exploration Agency (JAXA) devised a Venus orbiter, Akatsuki (formerly "Planet-C"), which was launched on May 20, 2010 but the craft failed to enter orbit in December 2010. Hopes remain that the probe can successfully hibernate and make another insertion attempt in six years. Planned investigations included surface imaging with an infrared camera and experiments designed to confirm the presence of lightning as well as the determination of the existence of current surface volcanism.
The European Space Agency (ESA) hopes to launch a mission to Mercury in 2014, called BepiColombo, which will perform two flybys of Venus before it reaches Mercury orbit in 2020.
Under its New Frontiers Program, NASA has proposed a lander mission called the Venus In-Situ Explorer to land on Venus to study surface conditions and investigate the elemental and mineralogical features of the regolith. The probe would be equipped with a core sampler to drill into the surface and study pristine rock samples not weathered by the very harsh surface conditions. The Venera-D probe is a proposed Russian space probe to Venus, to be launched around 2016 with its goal to make remote-sensing observations around the planet Venus and deploying a lander, based on the Venera design, capable of surviving for a long duration on the planet's surface. Other proposed Venus exploration concepts include rovers, balloons, and airplanes.
NASA has recommended the Surface and Atmosphere Geochemical Explorer (SAGE) candidate mission to land on Venus, with a possible launch in 2016.
Manned flyby
A manned Venus flyby mission, using Apollo program hardware, was proposed in the late 1960s. The mission was planned to launch in late October or early November 1973, and would have used a Saturn V to send three men to fly past Venus in a flight lasting approximately one year. The spacecraft would have passed approximately 5,000 kilometres from the surface of Venus about four months later.
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