Yesterday, the European Space Agency disclosed a serious problem early in the Sentinel-1A mission, which lifted off April 3 on a mission to observe the Earth. The spacecraft — which reportedly cost 280 million Euros ($384 million) to launch — came close to a collision in orbit.
“At the end of the first day after the launch (4 April): all deployments have been executed during the night and completed early in the morning at the beginning of the first ‘day shift’,” read a blog post from the Sentinel-1A team on the European Space Agency’s website.
“As the first day shift nears its end, a serious alert is received: there is a danger of a collision with a NASA satellite called ACRIMSAT, which has run out of fuel and can no longer be maneuvered. Not much information at the beginning, we are waiting for more information, but a collision avoidance maneuver may be needed. ‘Are you kidding? A collision avoidance maneuver during LEOP [launch and early orbit phase]? This has never been done before, this has not been simulated!’ ”
Worse, as controllers looked at the data they realized there was not one, but two possible points of collision. Cue the inevitable Gravity reference, and then a solution: to essentially move the satellite out of the way. The maneuver took about 39 seconds, and safely skirted Sentinel-1A out of danger.
After three shuttle flights, however, NASA discontinued use of the backpack in space for several reasons — most famously, safety considerations following the shuttle Challenger explosion of 1986. But thirty years on, the problem of dead satellites is growing. There are now thousands of pieces whipping around our planet, occasionally causing collisions and generally causing headaches for people wanting to launch stuff into orbit safely.
Space agencies such as NASA and the European Space Agency have been working hard on reducing debris during launches, but there’s still stuff from decades before. And when a satellite goes dead, if it’s in the wrong orbit it could be circling up there for decades before burning up. How do you fix that?
Robotics has come a long way in 30 years, so space agencies are looking to use those instead to pick up derelict satellites since that would pose far less danger to astronauts. One example is the e.DeOrbit mission recently talked about by ESA, which would pick up debris in polar orbits of altitudes between 800 and 1,000 kilometers (about 500 to 620 miles).
The mission would use autonomous control and image sensors to get up close to the drifting satellite, and then capture it in some way. Several ideas are being considered, ESA added. A big enough net could easily nab the satellite, or perhaps one could clamp on using tentacles or grab it with a harpoon or robotic arm. Here’s a 2013 proposal with more information on e.DeOrbit. ESA noted there is a symposium coming up May 6 to discuss this in more detail.
e.DeOrbit is one of just several proposals to pick satellites up. A Swiss idea called CleanSpace One appears to use a sort of pincer claw to grab satellites for retrieval. The Phoenix program (proposed by Defense Advanced Research Projects Agency) would take useable parts off of broken satellites for use in new satellites, and in past years DARPA had some ideas to remove satellites from orbit as well. Another option is satellite refueling to make these machines useable again, a possibility that NASA, Canada and many others are taking seriously.
What do you think is the best solution? Leave your thoughts in the comments.
Times are getting tougher in the battle to track space debris. A key asset in the fight to follow and monitor space junk is getting the axe on October 1st of this year. United States Air Force General and commander of Air Force Space Command William Shelton has ordered that the Air Force Space Surveillance System, informally known as Space Fence will be deactivated. The General also directed all related sites across the southern United States to prepare for closure.
This shutdown will be automatically triggered due to the U.S. Air Force electing not to renew its fifth year contract with Five Rivers Services, the Colorado Springs-based LLC that was awarded the contract for the day-to-day management of the Space Fence surveillance system in 2009.
To be sure, the Space Fence system was an aging one and is overdue for an upgrade and replacement.
The Space Fence system was first brought on line in the early days of the Space Age in the 1961. Space Fence was originally known as the Naval Space Surveillance (NAVSPASUR) system until passing into the custody of the U.S. Air Force’s 20th Space Control Squadron in late 2004. Space Fence is a series of multi-static VHF receiving and transmitting sites strung out across the continental United States at latitude 33° north ranging from California to Georgia.
Space Fence is part of the greater Space Surveillance Network, and comprises about 40% of the overall observations of space debris and hardware in orbit carried out by the U.S. Air Force. Space Fence is also a unique asset in the battle to track space junk and dangerous debris, as it gives users an “uncued” tracking ability. This means that it’s constantly “on” and tracking objects that pass overhead without being specifically assigned to do so.
Space Fence also has the unique capability to track objects down to 10 centimeters in size out to a distance of 30,000 kilometres. For contrast, the average CubeSat is 10 centimetres on a side, and the tracking capability is out to about 67% of the distance to geosynchronous orbit.
Exact capabilities of the Space Fence have always been classified, but the master transmitter based at Lake Kickapoo, Texas is believed to be the most powerful continuous wave facility in the world, projecting at 768 kilowatts on a frequency of 216.97927 MHz. The original design plans may have called for a setup twice as powerful.
A replacement for Space Fence that will utilize a new and upgraded S-Band radar system is in the works, but ironically, that too is being held up pending review due to the sequestration. Right now, the Department of Defense is preparing for various scenarios that may see its budget slashed by 150 to 500 billion dollars over the next 10 years.
The U.S. Air Force has already spent $500 million to design the next generation Space Fence, and awarded contracts to Raytheon, Northrop Grumman and Lockheed Martin in 2009 for its eventual construction.
The eventual $3 billion dollar construction contract is on hold, like so many DoD programs, pending assessment by the Strategic Choices and Management Review, ordered by Secretary of Defense Chuck Hagel earlier this year.
“The AFSSS is much less capable than the space fence radar planned for Kwajalein Island in the Republic of the Marshall Islands,” stated General Shelton in a recent U.S. Air Force press release. “In fact, it’s apples and oranges in trying to compare the two systems.”
One thing’s for certain. There will be a definite capability gap when it comes to tracking space debris starting on October 1st until the next generation Space Fence comes online, which may be years in the future.
In the near term, Air Force Space Command officials have stated that a “solid space situational awareness” will be maintained by utilizing the space surveillance radar at Eglin Air Force Base in the Florida panhandle and the Perimeter Acquisition Radar Characterization System at Cavalier Air Force Station in North Dakota.
We’ve written about the mounting hazards posed by space debris before. Just earlier this year, two satellites were partially damaged due to space debris. Space junk poses a grave risk to the residents of the International Space Station, which must perform periodic Debris Avoidance Maneuvers (DAMs) to avoid collisions. Astronauts have spotted damage on solar arrays and handrails on the ISS due to micro-meteoroids and space junk. And on more than one occasion, the ISS crew has sat out a debris conjunction that was too close to call in their Soyuz spacecraft, ready to evacuate if necessary.
In 2009, a collision between Iridium 33 and the defunct Cosmos 2251 satellite spread debris across low Earth orbit. In 2007, a Chinese anti-satellite missile test also showered low Earth orbit with more of the same. Ironically, Space Fence was crucial in characterizing both events.
Satellites, such as NanoSail-D2, have demonstrated the capability to use solar sails to hasten reentry at the end of a satellites’ useful life, but we’re a long ways from seeing this capability standard on every satellite.
Amateurs will be affected by the closure of Space Fence as well. Space Weather Radio relies on ham radio operators, who listen for the “pings” generated by the Space Fence radar off of meteors, satellites and spacecraft.
“When combined with the new Joint Space Operations Center’s high-performance computing environment, the new fence will truly represent a quantum leap forward in space situational awareness for the nation,” General Shelton said.
But for now, it’s a brave and uncertain world, as Congress searches for the funds to bring this new resource online. Perhaps the old system will be rescued at the 11th hour, or perhaps the hazards of space junk will expedite the implementation of the new system. Should we pass the hat around to “Save Space Fence?”
It’s sometimes tough being a satellite in Earth orbit these days.
An interesting commentary came our way recently via NASA’s Orbital Debris Program Office’s Orbital Debris Quarterly News. The article, entitled High-Speed Particle Impacts Suspected in Two Spacecraft Anomalies, highlights a growing trend in the local space environment.
The tale begins with GOES 13 located in geostationary orbit over longitude 75° West. Launched on May 24th, 2006 atop a Delta IV rocket, GOES 13 is an integral part of the U.S. National Oceanic and Atmospheric Administration (NOAA’s) Geostationary Operational Environmental Satellite network.
The problems began when GOES-13 began to suffer an “attitude disturbance of unknown origin” on May 22nd of this year, causing it to drift about two degrees per hour off of its required nadir (the opposite of zenith) pointing.
The anomaly was similar to a problem encountered by the NOAA 17 spacecraft on November 20th, 2005. At the time, the anomaly was suspected to be due to a micrometeoroid impact. The Leonid meteors, which peak right around the middle of November, were a chief suspect. However, NOAA 17 suffered a second failure 18 days later, which was later traced down to a hydrazine leak from its errant thrusters.
GOES-13 has weathered hard times before. Back in December of 2006, GOES-13’s Solar X-Ray Imager suffered damage after being struck by a solar flare shortly after initial deployment. GOES-13 also began returning degraded imagery in September 2012, forcing it into backup status for Hurricane Sandy.
GOES-13 was restored to functionality last month. Current thinking is that the satellite was struck by a micrometeorite. No major meteor showers were active at the time.
Loss of a GOES satellite would place a definite strain on our weather monitoring and Earth observing capability. Begun with the launch of GOES-1 in 1975, currently six GOES satellites are in operation, including one used to relay data for PeaceSat (GOES-7) and one used as a communications relay for the South Pole research station (GOES-3).
The GOES program cost NOAA billions in cost overruns to execute. The next GOES launch is GOES-R scheduled in 2015.
But the universe seems to love coincidences.
Less than 26 hours after the GOES 13 anomaly, Ecuador’s first satellite, NEE-01 Pegaso began to have difficulties keeping a stable attitude. The event happened shortly after passage near an old Soviet rocket booster (NORAD designation 1986-058B) which launched Kosmos 1768 on August 2nd, 1986. The U.S. Joint Space Operations Center had warned the fledgling Ecuadorian Space Agency that conjunction was imminent, but of course, there’s not much that could’ve been done to save the tiny CubeSat.
Although the main mass passed Pegaso at a safe distance, current thinking is that the discarded booster may have left a cloud of debris in its wake. Researchers have tracked small “debris clouds” around objects it orbit before- the collision of Iridium 33 and the defunct Kosmos 2251 on February 10th, 2009 left a ring of debris in its wake, and the Chinese anti-satellite test carried out on January 11th, 2007 showered low-Earth orbit with debris for years to come.
The loss represents a blow to Ecuador and their first bid to become a space-faring nation. Launched less than a month prior atop a Long March 2D rocket, Pegaso was a small 10 centimetre nanosatellite equipped with solar panels and dual infrared and visible Earth imaging systems.
A translation from the Ecuadorian Space Agencies site states that;
“The NEE-01 survived the crash and remains in orbit; however it has entered uncontrolled rotation due to the event.
Due to this rotation, (the satellite) cannot point its antenna correctly and stably to the Earth station and although still transmitting and running, the signal cannot be decoded. The Ecuadorian Civilian Space Agency is working tirelessly to stabilize the NEE-01 and recover the use of their signal.
The PEGASUS aired for 7 days your signal to the world via EarthCam, millions could see the Earth seen from space in real time, many for the first time, the files in those 7 days have been published after transmission.”
Ecuador plans to launch another CubeSat, NEE 02 Krysaor later in 2013. A carrier has not yet been named.
While both events suffered by the GOES-13 and NEE-01 Pegaso satellites were unrelated, they underscore problems with space junk and space environmental hazards that are occurring with a higher frequency.
Such is the modern hazardous environment of low Earth orbit that new satellites must face. With a growing amount of debris, impact threats are becoming more common. The International Space Station must perform frequent debris avoidance maneuvers to avoid hazards, and more than once, the crew has waited out a pass in their Soyuz escape modules should immediate evacuation become necessary. Punctures from micro-meteoroids or space junk have even been seen recently on the ISS solar panel arrays.
Plans are on the drawing board to deal with space junk, involving everything from “space nets” to lasers and even more exotic ideas. Probably the most immediate solution that can be implemented is to assure new payloads have a way to “self-terminate” via de-orbit at the end of their life span. Solar sail technologies, such as NanoSailD2 launched in 2010 have already demonstrated this capability.
Expect reentries also pick up as we approach the peak of solar cycle #24 at the end of 2013 and the beginning of 2014. Increased solar activity energizes the upper atmosphere and creates increased drag on low Earth satellites.
It’s a brave new world “up there,” and hazards, both natural and man-made, are something that space faring nations will have to come to terms with.
-Read and subscribe to the latest edition of NASA’s Orbital Debris Quarterly News for free here.
Action is needed soon to remove the largest pieces of space debris from orbit before the amount of junk destroys massive amounts of critical space infrastructure, according to a panel at the Sixth European Conference on Space Debris.
“Whatever we are going to do, whatever we have to do, is an expensive solution,” said Heiner Klinkrad, head of the European Space Agency space debris office, in a panel this week that was broadcast on ESA’s website.
“We have to compare the costs to solving the problem in an early stage as opposed to losing the infrastructure in orbit in the not-too-distant future.”
The panel estimated that there is $1.3 billion (1 billion Euros) worth of space satellite infrastructure that must be protected. The 200 most crucial satellites identified by the space community have an insured value of $169.5 million (130 million Euros), Klinkrad added.
Critical infrastructure, though not specified exactly by the panel, can include communication satellites and military eyes in the sky. Also at risk is that largest of human outposts in space — the International Space Station.
The conference concluded that without further action — even without launching any new rockets — it’s quite possible there could be a runaway effect of collisions producing debris within a few decades. Even a tiny object could act like a hand grenade in orbit if it smashes into a satellite, Klinkrad said.
To mitigate the situation, representatives suggested removing 5 to 10 large pieces of debris every year. They added they are uncertain about how soon a large problem would occur, but noted that the number of small objects is definitively increasing annually according to measurements done by the Walter Baade 6.5-meter Magellan Telescope.
“[It’s] something we haven’t know until now. We have been suspecting it is the case … this is a new result which is very important.”
While highlighting the risk, the European representatives of the panel added they are not standing idly by. Already, there are regulatory changes that could slow the problem for future launches — although there still will be cleanup to do from five past decades of space exploration.
A few of the points brought up:
– German officials are working on an in-orbit satellite servicing solution called DEOS. “The DEOS project will for the first time demonstrate technologies for the controlled in-orbit disposal of a defective satellite,” Astrium, the prime contractor for the definition phase, wrote in a press release in 2012. “In addition, DEOS will practice how to complete maintenance tasks – refuelling in particular – that extend the service life of satellites.”
– France’s Parliament passed the Space Operations Act in December 2010. “Its chief objective is to ensure that the technical risks associated with space activities are properly mitigated, without compromising private contractors’ competitiveness,” French space agency CNES wrote on its website. “The government provides a financial guarantee to compensate damages to people, property or the environment.”
– A United Nations subcommittee of the Committee on the Peaceful Uses of Outer Space is working on space sustainability guidelines that will include space debris and space operations practices. More details should be released in June, although Claudio Portelli (a representative from Italy’s space agency) warned he did not expect any debris removal proposals to emerge from this work.
Our very own International Space Station is in the cosmic crosshairs.
As cosmonauts are to begin Extra Vehicular Activity (EVA) this morning to perform routine maintenance, an article reminding us of the hazards of such activity came to us via NASA’s Orbital Debris Quarterly Newsletter.
The problem is Micrometeoroid and Orbital Debris (MMOD) impacts. These are nothing new. Pits and tiny cratering has been observed during post-flight inspections of space shuttle orbiters. But this is the first time we’d seen talk of damage caused by tiny impacts on the exterior of the International Space Station.
The handrails are a particularly sensitive area of concern.
The study examined damage incurred on handrails exposed to the environment of space for years on end. These present a hazard to spacewalking astronauts who rely on the handles to move about. These craters often become spalled, presenting a sharp metal rim raised from the surface of the handle.
Of course, these razor sharp rims present a problem, especially to space suit gloves. One 34.8 centimeter long handrail returned on the final Space Shuttle mission STS-135 had six impact craters along its length. The handrail had been in service and exposed to the vacuum of space for 8.7 years.
Craters as large as 1.85 millimetres (mm) in diameter with raised lips of 0.33mm have been observed on post-inspection. In studies conducted by NASA engineers, craters with lip heights as little as 0.25mm have been sufficient to snag and tear spacesuit gloves.
There have also been reported incidents of glove tears during EVAs conducted from the ISS over the years. For example, the report cites a tear noticed by astronaut Rick Mastracchio during STS-118 that cut the EVA short.
To protect astronauts and cosmonauts during EVAs, the following measures have been instituted:
– Toughening space suit gloves by adding reinforcement to areas exposed to potential MMOD damage.
– Monitoring and analyzing MMOD impacts along handrails and maintaining a database of problem areas.
– Equipping spacewalkers with the ability to cover and/or repair hazardous MMOD areas during spacewalks.
The studies were carried out by the Johnson Space Center Hypervelocity Impact Technology Group in conjunction with a test facility at White Sands, New Mexico. Astronaut Rick Mastracchio can also be seen talking about the hazards of spacewalking on this video.
Today’s 6 hour EVA by cosmonauts Vinogradov & Romanenko begins at 14:06 UT 10:06AM EDT.
This will be the 32nd Russian EVA from the International Space Station and will use the Pirs hatch on Zvezda.
Tasks include retrieving and installing experiment packages and replacing a defective retro-reflector device on the station’s exterior. The device is a navigational aid necessary for the Albert Einstein ATV-4 mission headed to the ISS on June 5th.
Progress 51P is also scheduled to launch towards the ISS next week on April 24 for docking on April 26th.
Debris in Low Earth Orbit is becoming an increasing concern. The Chinese anti-satellite test in 2007 and the collision of Kosmos 2251 and Iridium 33 in 2009 have increased hazards to the ISS. Many fear that a tipping point, known as an ablation cascade, could eventually occur with one collision showering LEO with debris that in turn trigger many more. The ISS was only finished in 2011, and it would be a tragic loss to see it abandoned due to a catastrophic collision only years after completion.
More than once, ISS crew members have sat out a debris conjunction that was too close to call in their Soyuz life boats, ready to evacuate the station if necessary. DAMs (Debris Avoidance Maneuvers) are now common for the ISS throughout the year.
Several ideas have been proposed to deal with space debris. In the past year, NanoSail-2D demonstrated the ability to deploy a solar sail from a satellite for reentry at the end of a spacecraft’s life span. Such technology may be standard equipment on future satellites.
Expect reentries to increase as we near the solar maximum for cycle #24 in late 2013 & early 2014. This occurs because the exosphere of Earth “puffs out” due to increased solar activity and increases drag on satellites in low Earth orbit.
All food for thought as we watch today’s EVA… space travel is never routine!
The April 2013 edition of the Orbital Debris Quarterly News is available for free online.
UPDATE (9/27/2012, 13:00 UTC) NASA now says that with additional tracking, they have determined the two pieces of space debris do not pose a threat to the ISS, and a debris avoidance maneuver scheduled for Thursday morning was cancelled by the flight control team at Mission Control. The ATV undocking time on Friday is still being decided at the time of this posting. See additional info at NASA’s website.(End of update)
International Space Station officials are keeping a watchful eye on two different pieces of space junk that may require the ISS to steer away from potential impact threats. Debris from the Russian COSMOS satellite and a fragment of a rocket from India may come close enough to the space station to require a debris avoidance maneuver. If needed, the maneuver would be done using the ESA’s Automated Transfer Vehicle (ATV) “Edoardo Amadi.” The ATV was supposed to undock last night, but a communications glitch forced engineers to call off the departure.
Both pieces of debris are edging just inside the so-called “red zone” of miss distance to the station with a time of closest approach calculated to occur Thursday at 14:42 UTC (10:42 a.m. Eastern time.) It is not known how large the object is.
An approach of debris is considered close only when it enters an imaginary “pizza box” shaped region around the station, measuring 1.5 x 50 x 50 kilometers (about a mile deep by 30 miles across by 30 miles long) with the vehicle in the center.
NASA says the three-person Expedition 33 crew is in no danger and continues its work on scientific research and routine maintenance. The current crew includes NASA astronaut Sunita Williams, Japanese astronaut Akihiko Hoshide and Russian cosmonaut Yuri Malenchenko.
If the maneuver is required – and NASA said it could be called off any time — it would occur at 12:12 UTC (8:12 a.m. EDT) Thursday, using the engines on the ATV, which remains docked to the aft port of the Zvezda Service Module. It usually takes about 30 hours to plan for and verify the need for an avoidance maneuver.
Debris avoidance maneuvers are conducted when the probability of collision is greater than 1 in 100,000, if it will not result in significant impact to mission objectives. If it is greater than 1 in 10,000, a maneuver will be conducted unless it will result in additional risk to the crew.
Only three times during the nearly 12 years of continual human presence on the ISS has a collision threat been so great that the crew has taken shelter in the Soyuz vehicles. (Those events occured on March 12, 2009, June 28, 2011 and March 24, 2012.) During those events, the station was not impacted. While the ISS likely receives small micrometeoroid hits frequently (based on experiments left outside the ISS and visual inspections of the station’s hull) no large debris impacts have occurred that have caused depressurization or other problems on the ISS.
Tuesday’s initial attempt to undock the ATV was called off due to a communications error between the Zvezda module’s proximity communications equipment and computers on the ATV. Russian engineers told mission managers that they fully understand the nature of the error and are prepared to proceed to a second undocking attempt, which has been postponed to Friday at the earliest, due to the potential space debris threat.
Once it is undocked, the ATV will move to a safe distance away from the station for a pair of engine firings that will send the cargo ship back into the Earth’s atmosphere to burn up over the Pacific Ocean.
The ATV still has extra fuel on board, and so the decision was made that if need, that available resource would be used.
Officials from Namibia have been examining a hollow ball that fell from the sky back in November 2011. So far, they haven’t had much luck identifying it, so have called in NASA and ESA, hoping the space agencies can provide some answers. The spherical object has a circumference of 1.1 meters (43 inches) and was found in a remote area in the northern part of the country, about 750 kilometers (480 miles) from the capital Windhoek, according to police forensics director Paul Ludik, quoted in an article by AFP.
Ludik described it as made of a “metal alloy known to man” (so cross alien spacecraft part off the list), weighing six kilograms (13 pounds).
This isn’t the first time balls from space have dropped in on unsuspecting countries.
Back in 2008 spherical objects fell to Brazil and Australia, and there have been previous reports of similar objects, as well.
After some post-crash forensics, the two objects in 2008 were identified the as a Composite Overwrapped Pressure Vessel (or COPV), which were carried on the space shuttles, and are a high pressure container for inert gases. COPVs have been used for a variety of space missions.
They are built with a carbon fiber or Kevlar overcoat to provide reinforcement against the vast pressure gradient between the inside and outside of the container, and so can survive re-entry through Earth’s atmosphere.
The one in Namibia was found 18 meters from its landing spot – it created a mini-crater 33 centimeters deep and 3.8 meters wide.
Other suggestions of what the object could be is a piece from a space gyroscope, a satellite part, a tank from one of the Apollo missions, or a part of a Russian spacecraft, (which have been known to crash to the ground, as well)
There’s a defunct 6.5-ton satellite heading our way. Trouble is, NASA’s not sure exactly where and when it might come down. And they’re not sure how much of it might survive its fiery fall through Earth’s atmosphere, either.
“Numerically, it comes out to a chance of 1-in-3,200 that one person anywhere in the world might be struck by a piece of debris,” said Nick Johnson, chief scientist with NASA’s Orbital Debris Program, during a media teleconference on Friday. “Those are obviously very, very low odds that anybody’s going to be impacted by this debris.”
Johnson reminded everyone that “throughout the entire 54 years of the space age, there have been no reports of anybody in the world being injured or severely impacted by any re-entering debris.”
How do you like your odds?
The huge 10-meter (35-ft) -long Upper Atmosphere Research Satellite (UARS) is in an orbit that crosses over six continents and three oceans. Johnson said it is expected to re-enter Earth’s atmosphere in an uncontrolled fall in late September or early October. While much of the spacecraft is expected to burn up during re-entry, it’s likely some pieces will make it to the ground. Current projections on where debris field might be is a 800-km- (500-mile) wide swath from Northern Canada to Southern South America.
Or it might fall in the ocean.
“We do know with 99.9 percent accuracy that it will re-enter the atmosphere somewhere between 57 degrees north and 57 degrees south, which means it will be anywhere from northern Canada to southern South America,” said Major Michael Duncan, deputy chief of space situational awareness with the Air Force’s U.S. Strategic Command. “That is truly the best estimation we can give you at this point in time.”
There are about 26 components that are big enough to survive and make it down to Earth, the largest weighing more than 150 kg (330 pounds.)
But hey, this happens all the time.
“Satellites re-entering is actually very commonplace,” Johnson said. “Last year, for example, we averaged over one object per day falling back uncontrolled into the atmosphere,” and for those coming back in an uncontrolled fashion – meaning it is a crapshoot when and where they fall — there were 75 metric tons of spacecraft and rocket bodies falling back to Earth.
“In perspective, UARS is less than six metric tons,” Johnson added. “So it’s a very small percentage of the annual re-entry of satellites.”
The majority of these satellites, though, were a lot smaller than UARS and they burn up completely in the atmosphere.
The UARS satellite launched from Space Shuttle Discovery in 1991. To give you an idea of how big the satellite is, it filled the shuttle’s payload bay completely. It had ten science instruments to examine the chemistry of the upper atmosphere and measure water vapor and other elements. It monitored the health of the ozone hole, looking at the amounts of aerosols in the atmosphere. In 2005 NASA determined that UARS was to be decommissioned.
It was never designed to be returned on the Space Shuttle, said Paul Hertz, chief scientist, NASA’s Science Mission Directorate.
Hertz said NASA is trying to keep the public informed about the the possibilities of debris failing and want to be up front about it. They will post all current information on www.nasa.gov/uars.
And Space Command will be tracking the satellite and providing updates as to where and when UARS will come down, and provide impact predictions if it looks like it will be coming down over land.
Although there are no hazardous materials on board – unlike the hydrazine on a National Reconnaissance Office spy satellite that was shot down in 2008 to avoid contaminating Earth – it was stressed that if anyone finds a piece of the satellite, they should not pick it up, but notify the local authorities.
But anyone along the final trajectory should get “a nice show,” Johnson said.
“It is a relatively large vehicle,” he said. “It would be visible in daylight. Odds are, though, it’s going to happen over an ocean, unlikely to be seen unless it’s by an airliner. We’ve had reports like that before. Since we don’t know where it’s going to come in, we can’t raise people’s expectations and tell them to go out and look in their backyard. So it’ll be a serendipitous kind of event.”
In the movie WALL-E, the Earth is surrounded by a dense field of orbiting junk. The problem of space debris is not that bad yet, but is potentially heading in that direction. A new report released today by the National Research Council says the problem of space debris is getting worse and has passed a “tipping point.” The report says that while NASA has done a good job using their available resources to research the issue, decreased funding and increased responsibilities for the space agency is not a good combination for the future, and NASA has not been able to keep pace with increasing hazards posed by abandoned equipment, spent rocket bodies, and other debris orbiting the Earth.
“The current space environment is growing increasingly hazardous to spacecraft and astronauts,” said Donald Kessler, chair of the committee that wrote the report and retired head of NASA’s Orbital Debris Program Office. “NASA needs to determine the best path forward for tackling the multifaceted problems caused by meteoroids and orbital debris that put human and robotic space operations at risk.”
There’s enough debris currently in orbit to continually collide and create even more debris, raising the risk of spacecraft failures, the report notes. In addition, collisions with debris have disabled and even destroyed satellites in the past, as in the collision in 2009 between an Iridium satellite and a inoperative Russian satellite. Several recent near-misses of the International Space Station requiring evasive maneuvers and sending astronauts to the Soyuz vehicles as a precaution underscores the value in monitoring and tracking orbital debris as precisely as possible.
It is fitting that Kessler lead this committee: he laid out a scenario back in 1978 called the Kessler Syndrome where the amount and size of objects in Earth’s orbit could eventually become so large that they would continually collide with one another and create even more debris, eventually causing a “cascade” of collisions which could make low Earth orbit unusable for decades.
From the new report, it appears the Kessler Syndrome is not just an abstract event that might occur in the future. It’s happening now. The amount of debris is now growing exponentially, as just two collisions since January 2007 has doubled the total number of debris fragments in Earth’s orbit, according to the NRC report.
NASA had asked for the report; specifically, NASA’s chief of safety and mission assurance, Bryan O’Connor, asked the NRC in 2010 to independently examine the agency’s work on debris.
“We thank the National Research Council for their thorough review in this report,” said NASA spokeswoman Beth Dickey. “We will study their findings and recommendations carefully and use them to advise our future actions in this important area of work.”
The report, however, does not provide NASA with many specific ideas but says NASA should develop a formal strategic plan to better allocate its limited resources devoted to the management of orbital debris. In addition, removal of debris from the space environment or other actions to mitigate risks may be necessary.
For example, NASA should initiate a new effort to record, analyze, report, and share data on spacecraft anomalies. This will provide additional knowledge about the risk from debris particulates too small to be cataloged under the current system yet large enough to potentially cause damage.
The report also suggests more work internationally on this problem, since it is a global problem caused by other nations besides the US. Over the past decade and a half, the world’s major space agencies have been developing a set of orbital debris mitigation guidelines aimed at stemming the creation of new space debris and lessening the impact of existing debris on satellites and human spaceflight. Most agencies are in the process of implementing or have already implemented these voluntary measures which include on-board passive measures to eliminate latent sources of energy related to batteries, fuel tanks, propulsion systems and pyrotechnics.
But the growing number of developing countries that are launching using satellites, and they need to be encouraged to use these measures as well.
In addition, NASA should lead public discussion of orbital debris and emphasize that it is a long-term concern for society that must continue to be addressed.
Congress also needs to be aware of the problem and provide adequate funding for the issue.