ISS Crew May Be Forced to Take Shelter from Space Debris

The International Space Station. Credit: NASA


Nov. 23 update: NASA reports that flight controllers have downgraded conjunction threat, and there is now no need for the crew to shelter in place on the space station.

What a fine welcome for the new crew on board the ISS: The three astronauts/cosmonauts on the space station may have to take shelter in their Soyuz spacecraft early Wednesday morning (Nov. 23), due to a close flyby or even a possible collision with a piece of space debris. Mission Control called up to the Expedition 30 at 2:06 pm EST today (Nov. 22), saying it was too late to do a debris avoidance maneuver with the entire station, and the crew should be ready to “shelter in place” in the Soyuz vehicle.

Reports are that the object is a piece of debris about 4 inches (10 centimeters) in diameter from the Chinese Fengyun 1C weather satellite that was destroyed in 2007. Current tracking indicates the object may come within 850 meters (2,800 feet) of the station.

An approach of debris is considered close only when it enters an imaginary “pizza box” shaped region around the station, measuring 0.75 kilometers above and below the station and 25 kilometers on each side (2,460 feet above and below and 15.6 by 15.6 miles). The undocking of the Expedition 29 crew yesterday altered the orbit of the ISS enough so that this object –which had previously not been a threat – is now on its way for a very close pass with the station.

Commander Dan Burbank and Flight Engineers Anton Shkaplerov and Anatoly Ivanishin will awake early and confer with Mission Control on the latest tracking data of the object, and decide by 4:30 a.m. EST (0930 UTC) on Nov. 23 if they should take shelter in the Soyuz.

NASA’s Chief Scientist for Orbital Debris Nicholas Johnson told Universe Today during a previous close conjunction of space debris and the ISS that on average, close approaches to ISS occur about three times a month.

Johnson said that small pieces of debris have already collided with ISS on many occasions, but these debris to date have not affected the safety of the crew or the operation of the mission. “The dedicated debris shields on ISS can withstand particles as large as 1 cm in diameter,” he said.

The crew has taken shelter in the Soyuz vehicles only twice during the 11 years of continual human presence on the ISS.

Space Junk Problem? Just Fire a Laser!

An computer generated image of objects in Low Earth Orbit that are currently being tracked. Approximately 95% of the objects in this illustration are orbital debris. Credit - NASA


Imagine yourself as an astronaut performing scientific experiments and crowd-stunning aerobatics. Suddenly, ear-stinging, blaring alarms go off. Mission Control radios that all space station personnel should evacuate to the rescue vehicles because a piece of deadly space debris is headed your way.

This scenario isn’t science fiction. In June of 2011, Universe Today reported that “six crew members on board the International Space Station were told to take shelter in…two Russian Soyuz spacecraft.” As more satellites reach the end of their operational lives, there will be more space junk emergencies in space and on the ground, undoubtedly with less pleasant results. Our young space faring society has been lucky so far: the ISS has been able to steer clear of space junk, and falling, uncontrolled satellites have thankfully fallen into the oceans. But one day our luck will run out.

There is hope, however. A new paper titled Removing Orbital Debris with Lasers published on arXiv proposes using a high-power pulsed laser system from Earth to create plasma jets on pieces of space debris, slowing them slightly, causing them to re-enter and burn up in the atmosphere or fall into the ocean.

Claude Phipps and his team from a high-tech company named Photonic Associates outlined their method, called Laser Orbital Debris Removal (LODR) which uses 15-year-old laser technology which is now readily available.

The team recognized that “thirty five years of poor housekeeping in space have created several hundred thousand pieces of space debris larger than one cm in the …low Earth orbit (LEO) band.” These may not seem like large objects, but with the energy density of dynamite, even a large paint chip can cause major damage.

The photo shows the "energy flash" when a projectile launched at speeds up to 17,000 miles an hour impacts a solid surface at the Hypervelocity Ballistic Range at NASA's Ames Research Center. This test is used to simulate what happens when a piece of orbital debris hits a spacecraft in orbit. Credit - NASA

Removing debris is an urgent task because the amount of debris currently in space poses “runaway collisional cascading,” with objects colliding with each other, creating even more pieces of debris.

There are other solutions besides creating a plasma jet, but they tend to be both less effective and more expensive.  A laser could be used to grind down an object into dust, but this would create an uncontrollable molten spray, making the problem worse.

Grappling the object or attaching a de-orbiting kit can both be effective. Unfortunately, they require a lot of fuel due to the need to accelerate to catch the object, which leads to more a more costly solution – about $27 million per object. Finally, there is the nuclear option of releasing a gas, mist, or aerogel to slow down objects, but this would affect both operational and non-operational spacecraft.

In their paper, Phipps and his team say that removing space junk by creating a jet of plasma of a few seconds in length with a laser is the best solution, costing only $1 million per big object removed and a few thousand for small objects. Furthermore, smaller objects can be de-orbited in merely one orbit, and a constellation of  “167 different objects can be addressed (hit with a laser) in one day, giving 4.9 years to re-enter” the atmosphere.

All 167 objects must carefully be tracked as to not change their paths of doom for the worse; however, it is possible to use the system to adjust orbits of space junk. That being said, current levels of space debris tracking are not adequate to implement LODR, but there is a dual benefit of easier removal and better avoidance with improve debris tracking. Better tracking will then allow for better control of the re-entry point and orbit modification with LODR, if necessary.

How can a light-push from a laser modify an orbit? While the laser doesn’t blast the debris out of the air, it is still effective because of the nature of orbital mechanics.

Imagine a cubesat that needs to be disposed of in a low altitude, perfectly circular orbit. The tap from a high powered laser and the plasma jet generated would push the cubesat out, farther away from Earth (higher in altitude) and into a more elliptical orbit.

This might seem like a horrible idea during the time the cubesat spends at a higher altitude, but as it comes half circle, it clips the atmosphere at a lower altitude since the ellipse is warped due adjustments by the laser. Since a low altitude corresponds to more drag, the cubesat slows down and locks into a lower orbit. This is why highly elliptical orbits are called transfer orbits, as they change lanes on the highway of space. Now, with the transfer orbit complete, the cubesat is slowed enough so that its orbit can no longer be achieved by the cubesat. The cubesat then falls out of the sky.

A picture showing the accelerations needed to transfer orbits, the laser provides acceleration and the atmosphere provides deceleration. Credit - Wikimedia Commons, AndrewBuck
The meat of the research for LODR deals with the atmosphere as the laser can become unfocused if the atmospheric turbulence is not addressed. LODR is complicated because the turbulence in the atmosphere causes distortions like those you see above a road on a hot summer’s day or like those you see when looking through a glass bottle. This complication is in addition to the aiming ahead needed to hit a target, just like the aiming ahead needed to hit a running player in dodgeball.

There are two ways to cancel turbulence.  First, one can shine a laser at a known spot in the atmosphere, exciting the sodium atoms at that location. Knowing the height of this dot in the sky, the system can then flex the reflecting mirror to bring the dot into focus moment-by-moment. It can then fire freely.

A second way involves the use of a Phase Conjugate (PC) mirror, otherwise known as a retroflector, which could automatically undo turbulence by sending light who’s phase variation has been reversed. That is to say it will send back an “oppositely distorted” laser beam whose distortion is un-done by the atmosphere creating a sharp laser beam.

An illustration of the distortion caused by both a phase conjugate mirror and a normal mirror. While both mirrors receive distorted images, the PC mirror results in a clear picture whereas a normal mirror is doubly distorted when passing through disrupting medium. Credit - Wikimedia Commons, Danh
LODR is not a silver bullet. Wired reports that “the main criticism of such a project would come from the international community, which might fear that a powerful enough laser could be used for military purposes such as hitting enemy satellites.” Wired then conducted an interview with Kessler; NASA’s former Senior Scientist for Orbital Debris Research who said, because of the politics involved, “any laser proposal is dead on arrival.” However, Phipps asserts to Wired that “If we get the right international cooperation, no one would believe the laser to be a weapon in sheep’s clothing.”

There are still unaddressed problems, as Kessler points out, hitting the wrong part of a space object would have disastrous results. “You might hit the wrong part of a satellite or could vaporize enough to cause it to explode.” In spite of that, careful study of the object could avoid any danger.

Space Junk Forces ISS Crew to Takes Shelter in Soyuz

A view of the ISS from a Soyuz spacecraft while space shuttle Endeavour was docked. Credit: NASA/ESA


The six crewmembers on board the International Space Station were told to take shelter in the two Russian Soyuz spacecraft early Tuesday because Space Command predicted a piece of space junk could make a close approach to the station. Radar tracking indicated the debris would make its close pass at 8:08 a.m. EDT (12:08 UTC), coming within about 243 meters (800 feet) of the station and well within the “pizza box” -shaped area around the ISS, but when no impact was detected the crew was told they could reenter the station and resume normal operations.

NASA’s Chief Scientist for Orbital Debris Nicholas L. Johnson told Universe Today during a previous “conjuction” of space debris and the ISS that on average, close approaches to ISS occur about three times a month. An approach of debris is considered “close” only when it enters an imaginary “pizza box” shaped region around the station, measuring 0.75 kilometers above and below the station and 25 kilometers on each side( 2,460 feet above and below and 15.6 by 15.6 miles).

Johnson said that small pieces of debris have already collided with ISS on many occasions, but these debris to date have not affected the safety of the crew or the operation of the mission. “The dedicated debris shields on ISS can withstand particles as large as 1 cm in diameter,” he said.

The piece of space junk was detected too late for the station to perform an evasive maneuver, so the crew was told to “shelter in place” on the two Soyuz spacecrafts. The crew on board is commander Andrey Borisenko, Alexander Samokutyaev and Ronald Garan, who took shelter aboard the Soyuz TMA-21 spacecraft docked to the Poisk module, and Sergei Volkov, Michael Fossum and Furukawa who went on to the Soyuz TMA-02M spacecraft docked to the Rassvet module.

Last & Best Chances to See NanoSail-D

Nanosail-D Pass Credit: Vesa Vauhkonen,


Over the next few weeks, skywatchers will have excellent viewing opportunities for the NanoSail-D solar sail.

The satellite is coming to the end of its 95-day mission to test the viability of de-orbiting decommissioned satellites or space debris. NanoSail-D is now de-orbiting and slowly losing altitude in the Earths thin upper atmosphere.

As the satellite descends, viewing opportunities will improve.

To see NanoSail-D pass over, you will need to know exactly when it will be visible from your location. To do this, go to or where star charts with times and pass details will be displayed after you enter your observing site.

Once you know the time and location in the sky of the pass of the satellite, make sure you are able to get a good view of the part of the sky where the satellite due to appear. Give yourself plenty of time, go outside and get ready. I always set a 30 second reminder on my watch or cell phone, so I don’t have to fumble around or guess the time.

To enjoy the NanoSail-D passes:

• Make sure you know the right place in the sky and the time of the pass, by checking on the web.
• Make sure you will be able to get a clear view of it from your viewing location.
• Set an alarm or get ready for the pass as it only lasts a few seconds.
• NASA expects NanoSail-D to stay in orbit through May 2011.
• If you are an astrophotographer, don’t forget, NASA and are having an imaging contest of NanoSail-D. Find out more here.
• Most of all, get your friends and family outside with you to watch NanoSail-D and enjoy!

Artist concept of Nanosail-D in Earth orbit. Credit: NASA

New Satellite for Monitoring Space Debris To Launch

The Air Force Space Based Space Surveillance (SBSS) system. Credit: Boeing


The U.S. Air Force will launch the first-ever satellite dedicated solely to tracking the positions of other satellites and the thousands of pieces of space debris in Earth orbit. The $500 million Space-Based Space Surveillance satellite, scheduled for a July 8 launch from Vandenberg Air Force Base, in California, will continuously monitor the “traffic” around the Earth, providing an unobstructed view day or night. Currently, the ground-based radar and optical telescopes used to track satellites and space junk can only be used on clear nights, and not all the observatories are powerful enough to detect objects in high or geosynchronous orbits.

This is the first satellite in the SBSS System that will eventually lead to a constellation of satellites to detect and track orbiting space objects, according to Boeing, the prime contractor for this first “Pathfinder” satellite. While the Air Force is the primary user of the SBSS satellites, the US Department of Defense will also use data from the eventual satellite system to support military operations, and NASA can use the information to calculate orbital debris collision-avoidance measures for the International Space Station and Space Shuttle missions.

The Air Force estimates there are about 1,000 functioning satellites and about 20,000 pieces of debris orbiting Earth.

The new satellite will be in orbit 627 kilometers (390 miles) above the Earth, and has an optical camera on a swivel mount, so the camera’s view can be changed without burning fuel to move the satellite, and will concentrate on satellites and debris in deep space. The information from the satellite will be sent to a command center at Schriever Air Force Base in Colorado.

The Air Force space surveillance network previously had partial use of a satellite called the Midcourse Space Experiment, which was designed to track missiles but could also monitor objects in orbit. It’s no longer functioning.

Right now, the Air Force can detect objects as small as 10 centimeters across, or about 4 inches, and they have not released information on the the capabilities of the new satellite.

The Secure World Foundation says there could be millions of pieces of debris in total around the Earth. Debris at altitudes above several hundred kilometers can stay in orbit for decades or even centuries, and those about 1,500 kilometers will remain in orbit for thousands of years. Even very small particles of space debris can have a devastating effect on anything they hit because of their high relative impact velocities.

Chart of orbital debris. Source: NASA Orbital Debris Quarterly News, April 2009,

This chart displays a summary of all objects in Earth orbit officially cataloged by the U.S. Space Surveillance Network. “Fragmentation Debris” includes satellite breakup debris and anomalous event debris, while “Mission?related Debris” includes all objects dispensed, separated, or released as part of the planned mission. Note the dramatic increase in fragmentation debris caused by the Chinese ASAT test conducted in January 2007. Another smaller increase is noted following the 2009 collision between an Iridum communications satellite and a non-functioning Russian satellite.

It is hoped the new SBSS satellite will increase the capabilities to help avoid future collisions.

Sources: Boeing, Secure World Foundation, AP

Climate Change Contributes to Space Junk Problem

An upper stage of a spacecraft exploding. Image Credit: ESA

The effects of climate change can be seen across the majority of the planet, but a new study reveals it is also affecting the space environment. New Scientist reports that increased carbon dioxide levels are cooling the upper atmosphere, which decreases the atmospheric density. This in turn affects how long defunct satellites, spent rocket boosters and other space debris stay in orbit, contributing to the space junk problem.

Atmospheric drag creates a braking effect on space debris, and eventually causes the various bits and pieces to drop out of orbit and burn up. Two researchers at the University of Southampton in the UK, Arrun Saunders and Hugh Lewis, studied the orbits of 30 satellites over the past 40 years, and recorded a gradual increase in the time they remain in orbit.

They calculated that at an altitude of 300 kilometers, the atmosphere is reducing in density by 5 per cent every decade. “The lower molecular braking means debris can remain in orbit up to 25 per cent longer,” said Lewis.

This raises the risk of collisions with satellites and makes it more hazardous to launch spacecraft. Space agencies and commercial launch companies may need to step up the current space debris mitigation procedures now in place, which include employing on-board passive measures to eliminate the potential for explosions from batteries, fuel tanks, propulsion systems and pyrotechnics, which helps reduce the number of objects in orbit. Or we may need to find a way to remove debris from orbit sooner rather than later.

Saunders and Lewis presented their work at a conference in Boulder, Colorado, last week.

Source: New Scientist

Asteroid or Space Junk? Object Makes Close Pass by Earth Wednesday

Asteroid or rocket booster? 2010 AL30 as imaged remotely from Australia on Jan. 11, 2010. Credit: Ernesto Guido & Giovanni Sostero

Caption: Asteroid or rocket booster? 2010 AL30 as imaged remotely from Australia on Jan. 11, 2010. Credit: Ernesto Guido & Giovanni Sostero, Remanzacco Observatory.

An unusual object will make a close flyby of Earth on Wednesday, coming within only 128,000 km (about 80,000 miles), or at a distance about three times less than the moon’s orbit. The object, named 2010 AL30, is about 10-15 meters long, and asteroid watchers say there is no chance it will hit the planet. But is it an asteroid or perhaps a piece of space junk, like a spent rocket booster?

UPDATE: The Solar System Dynamics website now says the object is an Apollo-type asteroid, which are Near-Earth asteroids that have orbits which cross the Earth’s orbit and pass approximately 1 AU or less from Earth.

According to Italian astronomers Ernesto Guido and Giovanni Sostero of the Remanzacco Observatory, who took this image (above) of 2010 AL30, it has an orbital period of almost exactly one year and might be a man-made object.

However, Alan Harris, senior researcher at the Space Science Institute said the object has a perfectly ordinary Earth-crossing orbit.

“Unlikely to be artificial, its orbit doesn’t resemble any useful spacecraft trajectory, and its encounter velocity with Earth is not unusually low,” he said.

The object make its closest approach at 12:48 GMT on Wednesday, and and amateur astronomers are encouraged to observe 2010 AL30 as a 14th magnitude star in the constellations of Orion, Taurus, and Pisces. Check here to get the ephemeris of the object from the Solar System Dynamics website.

Several observatories, including the Goldstone Radar will be observing NEO 2010 AL30 during its Earth flyby. After the January 13 close flyby, it will go too close to the Sun to be observed.

Sources: Remanzacco Observatory,

Space Junk Threatens Future Missions

Low Earth Orbit
Estimated number of objects in low Earth orbit. Credit: NASA

The U.S. Air Force began upgrading its ability to predict possible collisions in space after two satellites collided in February 2009, and has now done a collision analysis on over 800 maneuverable satellites. They hope to be able to track 500 more non-maneuvering satellites by year’s end. But maneuverable satellites aren’t the problem. The amount of space debris has risen by 40 per cent in the past four years alone. The Air Force Space Command now tracks 21,000 orbiting objects that are 10 centimeters or more across – including the 800 working satellites – and estimates that there are 500,000 smaller fragments in orbit.

“Our goal now is to do that conjunction assessment for all active satellites, roughly around 1,300 satellites, by the end of the year and provide that information to users as required,” said Lieutenant General Larry James, U.S. Strategic Command’s Joint Functional Component Command for Space, speaking at the Strategic Space Symposium this week in Omaha, Nebraska.

Some of the 500 satellites still to be assessed cannot be maneuvered in orbit because they are not functioning, or do not carry extra fuel that would be needed to move them once in orbit.

At another conference this week, the European Air and Space Conference in Manchester, UK, Hugh Lewis of the University of Southampton estimated the number of close encounters between objects in orbit will rise 50% in the next decade, and quadruple by 2059. The number of pieces of space debris has risen by 40% in the past four years alone.

Countermeasures by satellite builders and operators to avoid additional space debris are encouraged, but they add to the cost of missions.

Lewis has determined that compared with the 13,000 close approaches per week now, he projects there will be 20,000 a week in 2019 and upwards of 50,000 a week in 2059. From this he predicts that satellite operators will have to make five times as many collision avoidance maneuvers in 2059 as they will in 2019. “There’s going to be a big impact,” says Lewis. “You’re going to need more tracking to remove uncertainty about close approaches and undertake more maneuvers.”

Sources: Reuters, New Scientist