Mother Nature Network: Astronomers have no clue what's in 96 percent of the universe
NEW YORK — All the stars, planets and galaxies that can be seen today make up just 4 percent of the universe. The other 96 percent is made of stuff astronomers can't see, detect or even comprehend.
These mysterious substances are called dark energy and dark matter. Astronomers infer their existence based on their gravitational influence on what little bits of the universe can be seen, but dark matter and energy themselves continue to elude all detection.
"The overwhelming majority of the universe is: who knows?" explains science writer Richard Panek, who spoke about these oddities of our universe on Monday (May 9) at the Graduate Center of the City University of New York (CUNY) here in Manhattan. "It's unknown for now, and possibly forever."
In Panek's new book, The 4 Percent Universe (Houghton Mifflin Harcourt, 2011), Panek recounts the story of how dark matter and dark energy were discovered. It's a history filled with mind-boggling scientific surprises and fierce competition between the researchers racing to find answers.
Dark matter
Some of the first inklings astronomers had that there might be more mass in the universe than just the stuff we can see came in the 1960s and 1970s. Vera Rubin, a young astronomer at the Department of Terrestrial Magnetism at the Carnegie Institution of Washington, observed the speeds of stars at various locations in galaxies.
Simple Newtonian physics predicted that stars on the outskirts of a galaxy would orbit more slowly than stars at the center. Yet Rubin's observations found no drop-off at all in the stars' velocities further out in a galaxy. Instead, she found that all stars in a galaxy seem to circle the center at roughly the same speed.
"It means that galaxies should be flying apart, should be completely unstable," Panek said. "Something's missing here."
But research by other astronomers confirmed the odd finding. Ultimately, based on observations and computer models, scientists concluded that there must be much more matter in galaxies than what's obvious to us. If the stars and gas that we can see inside galaxies are only a small portion of their total mass, then the velocities make sense.
Astronomers nicknamed this unseen mass dark matter.
Where is it?
Yet, in the nearly 40 years that followed, researchers still haven't been able to figure out what dark matter is made of.
A popular hypothesis is that dark matter is formed by exotic particles that don't interact with regular matter, or even light, and so are invisible. Yet their mass exerts a gravitational pull, just like normal matter, which is why they affect the velocities of stars and other phenomena in the universe. [Video: Dark Matter in 3D]
However, try as hard as they might, scientists have yet to detect any of these particles, even with tests designed specifically to target their predicted properties.
"I think on the dark matter side there is some discouragement among the people who are kind of mid-career," Panek said. "They went into this field thinking, 'OK, we're going to solve this problem and then we'll build from there.' But 15, 20 years later, they're saying, 'I've invested my career in this and I don’t know if I'm going to find anything in my lifetime.'"
Still, many hold out hope that we're getting close and that experiments such as the newly built Large Hadron Collider particle accelerator in Geneva may finally solve the puzzle.
Dark energy
Dark energy is possibly even more baffling than dark matter. It's a relatively more recent discovery, and it's one that scientists have even less of a chance of understanding anytime soon.
It all started in the mid-1990s, when two teams of researchers were trying to figure out how fast the universe was expanding, in order to predict whether it would keep spreading out forever, or if it would eventually crumple back in on itself in a "Big Crunch."
To do this, scientists used special tricks to determine the distances of many exploded stars, called supernovas, throughout the universe. They then measured their velocities to determine how fast they were moving away from us.
When we view very distant stars, we are viewing an earlier time in the history of the universe, because those stars' light has taken millions and billions of light-years to travel to us. Thus, looking at the speeds of stars at various distances tells us how fast the universe was expanding at various points in its lifetime.
Astronomers predicted two possibilities: either the universe has been expanding at roughly the same rate throughout time, or that the universe has been slowing in its expansion as it gets older.
Shockingly, the researchers observed neither possibility. Instead, the universe appeared to be accelerating in its expansion.
That fact could not be explained based on what we knew of the universe at that time. All the gravity of all the mass in the cosmos should have been pulling the universe back inward, just as gravity pulls a ball back down to Earth after it's been thrown into the air.
"There's some other force out there or something on a cosmic scale that is counteracting the force of gravity," Panek explained. "People didn't believe this at first because it's such a weird result."
Fierce competition
Scientists named this mysterious force dark energy. Though no one has a good idea of what dark energy is, or why it exists, it is the force that appears to be counteracting gravity and causing the universe to accelerate in its expansion.
The lack of a good explanation for dark energy hasn't seemed to dampen scientists' enthusiasm for it.
"What I hear again and again is how excited people are to be working in this field right now, when this revolution is going on," Panek told SPACE.com. "The problems are so great and profound, they're actually rather thrilled with it."
Overall, dark energy is thought to contribute 73 percent of all the mass and energy in the universe. Another 23 percent is dark matter, which leaves only 4 percent of the universe composed of regular matter, such as stars, planets and people.
This bizarre, but apparently true, conclusion was reached at about the same time by the two groups working to measure the expansion of the universe. The competition between the groups became very contentious, Panek said, and they grew to dislike each other quite a lot.
Ultimately, though, members of both teams should reap the rewards of finding one of the biggest surprises in the history of science.
"I think that it's kind of assumed the dark energy will win the discoverers the Nobel," Panek said. "There certainly is that assumption that it's just a matter of years."
Friday, May 13, 2011
Giffords Coming To Husband's Endeavour Launch
International Business Times: Giffords Coming To Husband's Endeavour Launch
Arizona congresswoman Gabrielle Giffords, who was nearly slain down in an attempted homicide attempt earlier this year, will attend the space shuttle launch of her astronaut husband Mark Kelly.
Kelly is the commander of the SMS-134 mission on the Endeavour space shuttle, which will be making its final trip into space. The Endeavour is the second to last shuttle for the space shuttle program, which began over 30 years ago. After various delays nearly totaling a month, the Endeavour launch is finally set to take place on Monday May 16.
Giffords office said she'd be attending the launch, even while she recovers from a horrific attempt at her life back in January. NASA will provide Giffords' transportation to Florida, where she will not meet with the media and will watch the launch in private.
After the launch, members of Giffords' staff will meet with the media in the Kennedy Space Center News Center to discuss the event and her reaction to her husband's latest mission.
Meanwhile, NASA has said all systems are go for the launch and there should not be any further additional delays. The weather for Monday calls for 70 percent chance of acceptable conditions a launch time. There may be storm disturbance around the time the rotating service structure is to be rolled back, scheduled to begin at noon on Sunday, but other than that, NASA looks good to go.
SMS-134 will cap a nice career for Endeavour. Since its first mission, Endeavour has traveled 116,372,930 miles, spent 283 days in space and has had a total of 4,423 orbits. Over the years, it has housed many of space related milestones.
It was the first to include four spacewalks, and then the first to include five. One of its first missions, STS-67, set a length record almost two full days longer than any shuttle mission before it. Its airlock is the only one to have seen three spacewalkers exit through it for a single spacewalk. And in its cargo bay is where the International Space Station first started to be constructed.
During the 14-day mission, Endeavour and its crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. After it finishes up, NASA will conclude the space shuttle program with the Atlantis. Following that, the three remaining space shuttles and a fourth prototype will head to museums across the country.
Arizona congresswoman Gabrielle Giffords, who was nearly slain down in an attempted homicide attempt earlier this year, will attend the space shuttle launch of her astronaut husband Mark Kelly.
Kelly is the commander of the SMS-134 mission on the Endeavour space shuttle, which will be making its final trip into space. The Endeavour is the second to last shuttle for the space shuttle program, which began over 30 years ago. After various delays nearly totaling a month, the Endeavour launch is finally set to take place on Monday May 16.
Giffords office said she'd be attending the launch, even while she recovers from a horrific attempt at her life back in January. NASA will provide Giffords' transportation to Florida, where she will not meet with the media and will watch the launch in private.
After the launch, members of Giffords' staff will meet with the media in the Kennedy Space Center News Center to discuss the event and her reaction to her husband's latest mission.
Meanwhile, NASA has said all systems are go for the launch and there should not be any further additional delays. The weather for Monday calls for 70 percent chance of acceptable conditions a launch time. There may be storm disturbance around the time the rotating service structure is to be rolled back, scheduled to begin at noon on Sunday, but other than that, NASA looks good to go.
SMS-134 will cap a nice career for Endeavour. Since its first mission, Endeavour has traveled 116,372,930 miles, spent 283 days in space and has had a total of 4,423 orbits. Over the years, it has housed many of space related milestones.
It was the first to include four spacewalks, and then the first to include five. One of its first missions, STS-67, set a length record almost two full days longer than any shuttle mission before it. Its airlock is the only one to have seen three spacewalkers exit through it for a single spacewalk. And in its cargo bay is where the International Space Station first started to be constructed.
During the 14-day mission, Endeavour and its crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. After it finishes up, NASA will conclude the space shuttle program with the Atlantis. Following that, the three remaining space shuttles and a fourth prototype will head to museums across the country.
No, you are not losing your mind
If there were posts here yesterday that you read, which are not here today, it's because...they're not here.
Blogger.com, the platform that hosts this blog, was down for much of yesterday afternoon and all night...just coming up now (11 am mountain time.) And all posts made in the last couple of days have disappeared.
Supposedly, those posts will be restored. I'll give them a day to do so, and if not, will re-post them tomorrow.
Sorry for the inconvenience!
Blogger.com, the platform that hosts this blog, was down for much of yesterday afternoon and all night...just coming up now (11 am mountain time.) And all posts made in the last couple of days have disappeared.
Supposedly, those posts will be restored. I'll give them a day to do so, and if not, will re-post them tomorrow.
Sorry for the inconvenience!
Thursday, May 12, 2011
Washington Worries China Will Challenge U.S. Dominance in Space
Space.com: Washington Worries China Will Challenge U.S. Dominance in Space
U.S. power brokers aren't sure how to handle China's rapidly expanding space capabilities, according to testimony at a congressional hearing yesterday (May 11).
China recently demonstrated the ability to destroy satellites on orbit, and it's ramping up plans for a space station and a possible manned lunar landing in the next decade or so. At a hearing on "The Implications of China's Military and Civil Space Programs," a range of experts discussed what these developments might mean for the United States.
While opinions and viewpoints varied, a few key themes emerged, including the need to engage with China to better understand just what the nation hopes to achieve in space.
"There's still a lack of clear understanding of what Beijing's goals are, and how we interact with those," Ben Baseley-Walker of the Secure World Foundation, a non-profit organization committed to space sustainability, told SPACE.com. Baseley-Walker attended the hearing, which took place at the Capitol in Washington, D.C.
China's space capabilities ramping up
In 2007, China destroyed one of its own satellites on orbit during an anti-satellite test, showcasing an ability that makes the United States and other nations nervous. Since then, the country has conducted other tests advancing its military space capabilities, including a 2010 missile-interception demonstration.
Beijing is also ramping up its human spaceflight program. In 2003, China became the third nation to launch a person into space, and it has flown several manned missions since.
The country also hopes to build a large space station between 2015 and 2022, according to hearing panelist Alanna Krolikowski, a visiting scholar at George Washington University's Space Policy Institute.
And, beyond that, China appears to be gearing up for a manned lunar landing. The nation's human spaceflight program aims to complete an in-depth concept study on the subject by about 2020, Krolikowski said at the hearing.
These developments have some politicians and policy experts worried. They think China may be positioning itself to challenge outright the United States' dominance in space, which currently gives America a huge advantage on the battlefield.
“What concerns me most about the Chinese space program is that, unlike the U.S., it is being led by the People’s Liberation Army (PLA)," Congressman Frank Wolf (R-VA) testified at the hearing. "There is no reason to believe that the PLA’s space program will be any more benign than the PLA’s recent military posture."
Is Beijing a threat?
The White House has recently stated a willingness to work with China on expensive, difficult space projects, such as a manned mission to Mars. Wolf thinks this is a bad idea, citing the potential threat China poses as well as its abysmal human-rights record.
"The U.S. has no business cooperating with the PLA to help develop its space program," said Wolf, who chairs the commerce, justice and science subcommittee of the powerful House Appropriations Committee.
However, other panelists cited the possible benefits to the United States of such cooperation, which range from expanding opportunities for American businesses to increasing space security. If the United States thinks China can become a "normal" spacefaring country, keen to exploit space commercially, collaboration is probably a good idea, according to Krolikowski.
"As China invests in and derives greater benefit from space, it will acquire the same stake in creating a predictable, stable, safe and sustainable space environment that the U.S., Canada, Japan and European and other countries already share," Krolikowski said.
Cooperation and engagement could also help reveal China's goals for space. Does China, for example, hope to dominate military space aggressively in the near future, or is it concerned more about self-defense?
"While China’s capabilities in space are known to U.S. observers, its intentions are not," Krolikowski said.
According to Baseley-Walker, panelists stressed the importance of getting to the bottom of those intentions. It's difficult to draw up and implement effective policy, after all, without a basic understanding of where China is coming from, and where it's going.
U.S. power brokers aren't sure how to handle China's rapidly expanding space capabilities, according to testimony at a congressional hearing yesterday (May 11).
China recently demonstrated the ability to destroy satellites on orbit, and it's ramping up plans for a space station and a possible manned lunar landing in the next decade or so. At a hearing on "The Implications of China's Military and Civil Space Programs," a range of experts discussed what these developments might mean for the United States.
While opinions and viewpoints varied, a few key themes emerged, including the need to engage with China to better understand just what the nation hopes to achieve in space.
"There's still a lack of clear understanding of what Beijing's goals are, and how we interact with those," Ben Baseley-Walker of the Secure World Foundation, a non-profit organization committed to space sustainability, told SPACE.com. Baseley-Walker attended the hearing, which took place at the Capitol in Washington, D.C.
China's space capabilities ramping up
In 2007, China destroyed one of its own satellites on orbit during an anti-satellite test, showcasing an ability that makes the United States and other nations nervous. Since then, the country has conducted other tests advancing its military space capabilities, including a 2010 missile-interception demonstration.
Beijing is also ramping up its human spaceflight program. In 2003, China became the third nation to launch a person into space, and it has flown several manned missions since.
The country also hopes to build a large space station between 2015 and 2022, according to hearing panelist Alanna Krolikowski, a visiting scholar at George Washington University's Space Policy Institute.
And, beyond that, China appears to be gearing up for a manned lunar landing. The nation's human spaceflight program aims to complete an in-depth concept study on the subject by about 2020, Krolikowski said at the hearing.
These developments have some politicians and policy experts worried. They think China may be positioning itself to challenge outright the United States' dominance in space, which currently gives America a huge advantage on the battlefield.
“What concerns me most about the Chinese space program is that, unlike the U.S., it is being led by the People’s Liberation Army (PLA)," Congressman Frank Wolf (R-VA) testified at the hearing. "There is no reason to believe that the PLA’s space program will be any more benign than the PLA’s recent military posture."
Is Beijing a threat?
The White House has recently stated a willingness to work with China on expensive, difficult space projects, such as a manned mission to Mars. Wolf thinks this is a bad idea, citing the potential threat China poses as well as its abysmal human-rights record.
"The U.S. has no business cooperating with the PLA to help develop its space program," said Wolf, who chairs the commerce, justice and science subcommittee of the powerful House Appropriations Committee.
However, other panelists cited the possible benefits to the United States of such cooperation, which range from expanding opportunities for American businesses to increasing space security. If the United States thinks China can become a "normal" spacefaring country, keen to exploit space commercially, collaboration is probably a good idea, according to Krolikowski.
"As China invests in and derives greater benefit from space, it will acquire the same stake in creating a predictable, stable, safe and sustainable space environment that the U.S., Canada, Japan and European and other countries already share," Krolikowski said.
Cooperation and engagement could also help reveal China's goals for space. Does China, for example, hope to dominate military space aggressively in the near future, or is it concerned more about self-defense?
"While China’s capabilities in space are known to U.S. observers, its intentions are not," Krolikowski said.
According to Baseley-Walker, panelists stressed the importance of getting to the bottom of those intentions. It's difficult to draw up and implement effective policy, after all, without a basic understanding of where China is coming from, and where it's going.
NASA Plans Test of New Moon Lander Morpheus
FoxNews: NASA Plans Test of New Moon Lander Morpheus
squat, insectlike contraption is set to fly untethered for the first time soon in a NASA test of technologies designed to take humans to the moon, Mars or beyond.
The unmanned Morpheus lander, named after the Greek god of dreams, was built at NASA's Johnson Space Center in Houston using cutting-edge technologies that the agency hopes will one day enable manned missions to another planet or even an asteroid. The vehicle, about the size of an SUV, could carry about 1,100 pounds (500 kg) of cargo to the moon.
Not only are the technologies onboard innovative, but NASA's process of building the lander is, too.
"Part of what this project set out to do was to question the way we've done things," Project Morpheus manager Matt Ondler told SPACE.com. "We purposefully set out to see if we could do things faster and cheaper, leveraging off the work that was already done."
So far, the project has cost NASA about $4 million over the last 18 months, not counting the NASA work force, which is accounted for under NASA's general overhead.
Cutting-edge tech
One of the primary technologies being tested on the lander is a system intended to spot dangerous craters or boulders that could make a landing spot on another planet unsafe. The so-called Automated Landing and Hazard Avoidance Technology — or ALHAT — uses lasers to image the surface of a body and identify hazards as it flies over.
Previous missions, such as the Apollo 11 moon landing, have taught us that such a capability could be critical. When Neil Armstrong, Buzz Aldrin and Michael Collins were nearing the lunar surface on that first moon trip, they almost ran out of fuel while looking for a suitable spot to touch down.
Another innovation being tested on Morpheus is a lighter, safer mix of fuel.
The landing machine is powered by liquid oxygen and methane, which NASA says is a safer alternative to traditional spacecraft propellants. Not only that, but it's 10 to 20 times less expensive and weighs significantly less — an important distinction when every pound of weight carried into space requires an additional 15 pounds of fuel to get it there.
Such a fuel mix might also be renewable at the spacecraft's destination. Engineers are already working on methods to extract oxygen from the lunar surface, and methane is known to exist in the atmosphere on Mars.
Tethered tests
Morpheus has already undergone several tests while tethered to a crane so it doesn't get out of control. But these haven't always gone quite as planned.
One test on April 27, for example, had to be aborted after the lander started swinging wildly. In NASA parlance, "shortly after ignition the vehicle pitched over and control authority was lost," according to a NASA Morpheus blog.
But the Morpheus researchers aren't discouraged, and are gearing up for the machine's biggest test to date: an untethered, free flight up to an altitude of 100 feet (30 meters), then over 100 feet to the west, then a landing.
The exact date for this test isn't yet set, but mission managers expect it to occur sometime in June.
"There are still a few more issues that we're working through," Ondler said. "We want to have two complete tethered flights in a row with no anomalies before we go untethered."
The test will be a significant milestone for the Morpheus project.
"It's sort of like taking the training wheels off," Ondler said. "If we've done everything right, it should work just fine, but there's no safety net to catch it if things don't go right."
The project involves about 30 mostly full-time workers, plus another 30 part-time employees at Johnson Space Center, Ondler said.
"For a lot of the people here, this is why they came to NASA," Ondler said. "It was to build stuff, to light engines off and fly things, so I think it's been very exciting for people who've had a chance to work on it."
Ondler said the work on Morpheus is going so well, NASA hopes to expand the development model to more projects throughout the agency, both at Johnson Space Center and other NASA centers around the country.
"Projects like Morpheus are invigorating and infectious," said Steve Altemus, director of Johnson's Engineering Directorate, in a statement. "And they help us find better and cheaper ways to do things. To challenge our existing processes. To innovate."
Endeavour Crew Arrives at Space Center for Monday Launch
PC Magazine: Endeavour Crew Arrives at Space Center for Monday Launch
The space shuttle Endeavour crew has returned to Kennedy Space Center in preparation for Monday's re-scheduled launch.
The six astronauts for the mission known as STS-134 arrived in Florida via a shuttle training aircraft at 9am Eastern.
"It's great to be back," shuttle commander Mark Kelly said in a statement. "We really appreciate all the hard work by the team that's worked over the last couple of weeks to get shuttle Endeavour ready."
"I can't think of a more perfect way to spend my birthday then to come here with my crew a get ready to fly Endeavour next week," said Endeavour's pilot Greg H. Johnson.
Later today, Kelly and Johnson will practice landings in the Shuttle Training Aircraft, which are Gulfstream II jets modified to handle like a space shuttle, according to NASA.
Mission specialists Michael Fincke, Greg Chamitoff, Andrew Feustel and the European Space Agency's Roberto Vittori will also travel to the International Space Station via Endeavour for the 14-day mission. Endeavour is scheduled to depart at 8:56am Monday, May 16. Shuttle Weather Officer Kathy Winters has forecasted a 70 percent chance of having good weather.
Endeavour was initially scheduled to launch on Friday, April 29, but just prior to the scheduled 3:47pm launch, NASA discovered that Endeavour's auxiliary power unit had failed. It was so late in the game that the mission's astronauts were already en route to the shuttle. NASA quickly shut things down, and upon further inspection, discovered a problem with a box of switches that controls power feeds, known as a load control assembly-2 (LCA-2). NASA removed the malfunctioning box last week and replaced it with a new one.
Among the items Endeavour will carry to the ISS is the Alpha Magnetic Spectrometer-2 (AMS). It will be used to measure cosmic rays to gain a better understanding of cosmic radiation; a challenge for long-duration spaceflight. It might also help uncover the mysteries involved in dark matter or missing antimatter, NASA said. The 15,000-pound AMS is expected to be operational for the rest of the station's life; at least 10 years.
The space shuttle Endeavour crew has returned to Kennedy Space Center in preparation for Monday's re-scheduled launch.
The six astronauts for the mission known as STS-134 arrived in Florida via a shuttle training aircraft at 9am Eastern.
"It's great to be back," shuttle commander Mark Kelly said in a statement. "We really appreciate all the hard work by the team that's worked over the last couple of weeks to get shuttle Endeavour ready."
"I can't think of a more perfect way to spend my birthday then to come here with my crew a get ready to fly Endeavour next week," said Endeavour's pilot Greg H. Johnson.
Later today, Kelly and Johnson will practice landings in the Shuttle Training Aircraft, which are Gulfstream II jets modified to handle like a space shuttle, according to NASA.
Mission specialists Michael Fincke, Greg Chamitoff, Andrew Feustel and the European Space Agency's Roberto Vittori will also travel to the International Space Station via Endeavour for the 14-day mission. Endeavour is scheduled to depart at 8:56am Monday, May 16. Shuttle Weather Officer Kathy Winters has forecasted a 70 percent chance of having good weather.
Endeavour was initially scheduled to launch on Friday, April 29, but just prior to the scheduled 3:47pm launch, NASA discovered that Endeavour's auxiliary power unit had failed. It was so late in the game that the mission's astronauts were already en route to the shuttle. NASA quickly shut things down, and upon further inspection, discovered a problem with a box of switches that controls power feeds, known as a load control assembly-2 (LCA-2). NASA removed the malfunctioning box last week and replaced it with a new one.
Among the items Endeavour will carry to the ISS is the Alpha Magnetic Spectrometer-2 (AMS). It will be used to measure cosmic rays to gain a better understanding of cosmic radiation; a challenge for long-duration spaceflight. It might also help uncover the mysteries involved in dark matter or missing antimatter, NASA said. The 15,000-pound AMS is expected to be operational for the rest of the station's life; at least 10 years.
Monday, May 9, 2011
Ugly Truth of Space Junk: Orbital Debris Problem to Triple by 2030
Space.com: Ugly Truth of Space Junk: Orbital Debris Problem to Triple by 2030
COLORADO SPRINGS, Colo. -- Dealing with the decades of detritus from using outer space -- human-made orbital debris -- is a global concern, but some experts are now questioning the feasibility of the wide range of "solutions" sketched out to grapple with high-speed space litter.
What may be shaping up is an "abandon in place" posture for certain orbital altitudes -- an outlook that flags the messy message resulting from countless bits of orbital refuse.
In a recent conference here, Gen. William Shelton, commander of the U.S. Air Force Space Command, relayed his worries about rising amounts of human-made space junk.
"The traffic is increasing. We've now got over 50 nations that are participants in the space environment," Shelton said last month during the Space Foundation’s 27th National Space Symposium. Given existing space situational awareness capabilities, over 20,000 objects are now tracked. [Worst Space Debris Events of All Time]
"We catalog those routinely and keep track of them. That number is projected to triple by 2030, and much of that is improved sensors, but some of that is increased traffic," Shelton said. "Then if you think about it, there are probably 10 times more objects in space than we're able to track with our sensor capability today. Those objects are untrackable … yet they are lethal to our space systems -- to military space systems, civil space systems, commercial -- no one’s immune from the threats that are on orbit today, just due to the traffic in space."
Tough neighborhood
From a probability point of view, General Shelton added, smaller satellites, more debris, more debris is going to run into more debris, creating more debris. [Video: Fragmentation: Growing Threat of Space Junk]
"It may be a pretty tough neighborhood," Shelton continued, in low-Earth orbit and geosynchronous Earth orbit "in the not too distant future."
When asked if the U.S. Air Force plans on funding space debris mitigation capability, Shelton responded: "We haven’t found a way yet that is affordable and gives us any hope for mitigating space debris. The best we can do, we believe, is to minimize debris as we go forward with our operations. As we think about how we launch things, as we deploy satellites, minimizing debris is absolutely essential and we’re trying to convince other nations of that imperative as well."
Shelton said that, unfortunately, with the duration of most things on orbit, "you get to live with the debris problem for many, many years and in some cases decades. So minimizing debris is important to us and it should be to other nations as well."
Point of no return
The concern over orbital debris has been building for several reasons, said Marshall Kaplan, an orbital debris expert within the Space Department at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
In Kaplan's view, spacefaring nations have passed the point of "no return," with the accumulation of debris objects in low-Earth orbits steadily building over the past 50 years.
Add to the clutter, the leftovers of China’s anti-satellite (ASAT) test in 2007.
"The fact that this single event increased the number of debris objects by roughly 25 percent was not as important as the location of the intercept. The event took place at an altitude of 865 kilometers, right in the middle of the most congested region of low-orbiting satellites," Kaplan pointed out.
Toss into the brew the collision of an Iridium satellite with an expired Russian Cosmos spacecraft in February 2009 -- at an altitude similar to that of China’s ASAT test.
As a result of 50 years of launching satellites and these two events, the altitude band from about 435 miles (700 km) to a little over 800 miles (1,300 km) has accumulated possibly millions of debris objects ranging from a few millimeters to a few meters, Kaplan said.
Complex and very expensive
"The buildup of debris is not a naturally reversible process. If we are to clean up space, it will certainly be complex and very expensive. If we continue, as we have, to use these very popular orbits in near-Earth space, the density of debris and collision events will surely increase," Kaplan told SPACE.com.
The good news is that no immediate action is necessary in terms of removing debris objects, Kaplan advised, as experts estimate that the situation will not go unstable anytime soon.
"But, when it does, operational satellites will be destroyed at an alarming rate, and they cannot be replaced. We must prepare for this seemingly inevitable event," Kaplan said. While there are many options for debris removal that have been proposed, he feels that none are sensible.
"Barring the discovery of a disruptive technology within the next decade or so, there will be no practical removal solution," Kaplan added. "We simply lack the technology to economically clean up space." [Lasers Could Zap Space Junk Clear From Satellites]
For Kaplan, the issue of dealing with orbital debris will become dire.
"The proliferation is irreversible. Any cleanup would be too expensive. Given this insight, it is unlikely spacefaring nations are going to do anything significant about cleaning up space," Kaplan said. "The fact is that we really can't do anything. We can't afford it. We don't have the technology. We don't have the cooperation. Nobody wants to pay for it. Space debris cleanup is a 'growth industry,' but there are no customers. In addition, it is politically untenable."
All that being said, can anything be done? Kaplan says he can imagine the future … and things don't look pretty.
"There is a good chance that we may have to eventually abandon all active satellites in currently used orbits," Kaplan said. "One possible scenario for the future is that we may phase out this generation of spacecraft while replacing them with a brand-new infrastructure of low-orbiting constellations of small satellites, each of which partially contributes to collecting desired data or making communications links."
These constellations could be placed below 370 miles (600 km), thus avoiding the debris issue.
"Such a new infrastructure could be developed over the next 20, 30 or 40 years," Kaplan said. "We should have plenty of time to make the transition, so let's use it wisely. We all caused this problem … there is no doubt about that. And, nobody will claim somebody else did it."
Meanwhile, outer space is still "big" … but it’s getting smaller.
"The question is: when is it going to get too small? That’s the real question, and we don't know," Kaplan said. "Nobody is really going to yell uncle until we have some more serious collisions. That could happen anytime or it could happen in 20 years, we just don't know."
COLORADO SPRINGS, Colo. -- Dealing with the decades of detritus from using outer space -- human-made orbital debris -- is a global concern, but some experts are now questioning the feasibility of the wide range of "solutions" sketched out to grapple with high-speed space litter.
What may be shaping up is an "abandon in place" posture for certain orbital altitudes -- an outlook that flags the messy message resulting from countless bits of orbital refuse.
In a recent conference here, Gen. William Shelton, commander of the U.S. Air Force Space Command, relayed his worries about rising amounts of human-made space junk.
"The traffic is increasing. We've now got over 50 nations that are participants in the space environment," Shelton said last month during the Space Foundation’s 27th National Space Symposium. Given existing space situational awareness capabilities, over 20,000 objects are now tracked. [Worst Space Debris Events of All Time]
"We catalog those routinely and keep track of them. That number is projected to triple by 2030, and much of that is improved sensors, but some of that is increased traffic," Shelton said. "Then if you think about it, there are probably 10 times more objects in space than we're able to track with our sensor capability today. Those objects are untrackable … yet they are lethal to our space systems -- to military space systems, civil space systems, commercial -- no one’s immune from the threats that are on orbit today, just due to the traffic in space."
Tough neighborhood
From a probability point of view, General Shelton added, smaller satellites, more debris, more debris is going to run into more debris, creating more debris. [Video: Fragmentation: Growing Threat of Space Junk]
"It may be a pretty tough neighborhood," Shelton continued, in low-Earth orbit and geosynchronous Earth orbit "in the not too distant future."
When asked if the U.S. Air Force plans on funding space debris mitigation capability, Shelton responded: "We haven’t found a way yet that is affordable and gives us any hope for mitigating space debris. The best we can do, we believe, is to minimize debris as we go forward with our operations. As we think about how we launch things, as we deploy satellites, minimizing debris is absolutely essential and we’re trying to convince other nations of that imperative as well."
Shelton said that, unfortunately, with the duration of most things on orbit, "you get to live with the debris problem for many, many years and in some cases decades. So minimizing debris is important to us and it should be to other nations as well."
Point of no return
The concern over orbital debris has been building for several reasons, said Marshall Kaplan, an orbital debris expert within the Space Department at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
In Kaplan's view, spacefaring nations have passed the point of "no return," with the accumulation of debris objects in low-Earth orbits steadily building over the past 50 years.
Add to the clutter, the leftovers of China’s anti-satellite (ASAT) test in 2007.
"The fact that this single event increased the number of debris objects by roughly 25 percent was not as important as the location of the intercept. The event took place at an altitude of 865 kilometers, right in the middle of the most congested region of low-orbiting satellites," Kaplan pointed out.
Toss into the brew the collision of an Iridium satellite with an expired Russian Cosmos spacecraft in February 2009 -- at an altitude similar to that of China’s ASAT test.
As a result of 50 years of launching satellites and these two events, the altitude band from about 435 miles (700 km) to a little over 800 miles (1,300 km) has accumulated possibly millions of debris objects ranging from a few millimeters to a few meters, Kaplan said.
Complex and very expensive
"The buildup of debris is not a naturally reversible process. If we are to clean up space, it will certainly be complex and very expensive. If we continue, as we have, to use these very popular orbits in near-Earth space, the density of debris and collision events will surely increase," Kaplan told SPACE.com.
The good news is that no immediate action is necessary in terms of removing debris objects, Kaplan advised, as experts estimate that the situation will not go unstable anytime soon.
"But, when it does, operational satellites will be destroyed at an alarming rate, and they cannot be replaced. We must prepare for this seemingly inevitable event," Kaplan said. While there are many options for debris removal that have been proposed, he feels that none are sensible.
"Barring the discovery of a disruptive technology within the next decade or so, there will be no practical removal solution," Kaplan added. "We simply lack the technology to economically clean up space." [Lasers Could Zap Space Junk Clear From Satellites]
For Kaplan, the issue of dealing with orbital debris will become dire.
"The proliferation is irreversible. Any cleanup would be too expensive. Given this insight, it is unlikely spacefaring nations are going to do anything significant about cleaning up space," Kaplan said. "The fact is that we really can't do anything. We can't afford it. We don't have the technology. We don't have the cooperation. Nobody wants to pay for it. Space debris cleanup is a 'growth industry,' but there are no customers. In addition, it is politically untenable."
All that being said, can anything be done? Kaplan says he can imagine the future … and things don't look pretty.
"There is a good chance that we may have to eventually abandon all active satellites in currently used orbits," Kaplan said. "One possible scenario for the future is that we may phase out this generation of spacecraft while replacing them with a brand-new infrastructure of low-orbiting constellations of small satellites, each of which partially contributes to collecting desired data or making communications links."
These constellations could be placed below 370 miles (600 km), thus avoiding the debris issue.
"Such a new infrastructure could be developed over the next 20, 30 or 40 years," Kaplan said. "We should have plenty of time to make the transition, so let's use it wisely. We all caused this problem … there is no doubt about that. And, nobody will claim somebody else did it."
Meanwhile, outer space is still "big" … but it’s getting smaller.
"The question is: when is it going to get too small? That’s the real question, and we don't know," Kaplan said. "Nobody is really going to yell uncle until we have some more serious collisions. That could happen anytime or it could happen in 20 years, we just don't know."
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