Fast forward to our current time and we've now got a different problem on our hands.Space is getting crowded with an increasing number of satellites in earth orbit, with more countries developing their own space programmes alongside billionaires who have their own privately- funded space travel plans.
Space junk now principally refers to the debris of numerous explosions and accidents which has gradually accumulated over the last 50+ years. The larger pieces are easier to track and avoid but the main bulk is made up of small if not tiny flecks of metal or paint and other debris which can inflict real damage on satellites, the International Space Station (ISS), the Hubble Telescope and spacecraft.
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MAJOR INCIDENTS
In April this year, India's recent missile test shot down a satellite and created 400 pieces of orbital debris. NASA have been tracking objects from the explosion that are big enough to track - about 10cms (6ins). Some 60 have so far been found. The Indian satellite was in a low altitude of 180mls, well below the ISS and most satellites. NASA are mort concerned about 40 objects above the ISS. They estimate that the risk of any of these colliding with the ISS had increased by 44%,
According to Michael Safi and Hannah Devlin's story on the incident in The Guardian the US military are currently tracking 23,000 objects larger than 10cm. This includes 10,000 pieces of space debris.
Nearly 3,000 of these were created in January 2007 when China tested an anti-satellite weapon on an old Fengyun weather satellite at an altitude of 530mls.
The other biggest space junk incident was in February 2009, when an Iridium telecoms satellite and Kosmos-2251, a Russian military satellite, accidentally collided.
In 2012, the crew of the International Space Station was forced to shelter in the Soyuz escape capsules when debris from this collision passed close by.
See also: 'Top 10 Space Age Radiation Incidents' by Patrick Weidinger [Jan 20th 2012] and 10 Eye-Opening Facts About Space Junk on the Listverse.com wensite.
The other biggest space junk incident was in February 2009, when an Iridium telecoms satellite and Kosmos-2251, a Russian military satellite, accidentally collided.
In 2012, the crew of the International Space Station was forced to shelter in the Soyuz escape capsules when debris from this collision passed close by.
See also: 'Top 10 Space Age Radiation Incidents' by Patrick Weidinger [Jan 20th 2012] and 10 Eye-Opening Facts About Space Junk on the Listverse.com wensite.
Experts are concerned that collisions will get more frequent, which could in turn trigger off a cascade effect with fragments creating further collisions as in the movie Gravity.
European Space Agency (ESA) statistical models calculate that the Earth is ringed by 900,000 pieces of debris larger than a marble. Some 34,000 of these measure more than 10cm.
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CROWDED SPACE/INTERNET SATELLITE CONSTELLATIONS
Satellites are getting smaller and cheaper to launch. Scientists, companies and even schools can build one to photograph Earth for as little as $10,000.
On a larger scale, a number of major companies are seeking to build and launch internet constellations in what is turning into a battle of the billionaires.
Source: Pocket-Lint
In 2018, Elon Musk's company SpaceX, based in Hawthorne, California, announced a project named Starlink which initially planned to launch a constellation of 4,425 satellites in low Earth orbit. After the Federal Communications Commission (FCC) approved an additional 7,518 satellites late last year, SpaceX expanded the quota to 11,943 satellites. Only two prototype Starlink satellites have so far been launched. The FCC claims the project won’t be operational until at least 800 satellites are deployed.
In April 2019, Amazon announced Project Kuiper, a plan to construct a broadband internet constellation of 3,236 satellites that will work in concert with Amazon's planned large network of 12 satellite ground station facilities announced in November 2018. A valuable detailed up-to-date story by Alan Boyle on GeekWire outlines Amazon's plans and those of the other runners and riders listed below
On the 8th April The Observer published a story by Sissi Cao entitled 'Jeff Bezos Poaches SpaceX’s Satellite Team to Build a Very Similar Project for Amazon. She reports that 'Bezos had hired SpaceX’s former vice president of satellites, Rajeev Badyal, and several members of his team, to lead Amazon’s Project Kuiper, Badyal was the head of SpaceX’s “Starlink” project, a very similar effort to Amazon’s Project Kuiper but at a larger scale. Badyal was fired by Elon Musk in June last year, one due to Musk’s dissatisfaction on the progress of Starlink.'
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| OneWeb satellite |
In 2015, OneWeb [Formerly WorldVU] announced plans for a 650-satellite constellation to provide global Internet broadband services starting in 2021. Their first six French-built satellites were launched on Feb 27th 2019. According to 'How OneWeb plans to make sure its first satellites aren’t its last' by Caleb Henry on the SpaceNews website [March 18, 2019]
'If all continues to go as planned, OneWeb’s first six spacecraft will finish on-orbit testing this spring, clearing the path for an initial system of 648 satellites — 600 operational and 48 spares — and setting the stage for a larger system that could eventually number 900 or more satellites.
'Orbiting the initial 648-satellite constellation will entail the largest launch campaign in history. In late summer of early fall, OneWeb expects to start launching 30 or so satellites at a time on Soyuz rockets lifting off every three to four weeks.'
'OneWeb and its satellite manufacturing partner Airbus Defence and Space have crammed 10 gigabits per second of capacity into spacecraft the size of dishwashers. OneWeb satellites cost $1 million each to produce, and the companies will be able to complete 350 to 400 satellites annually from their joint venture $85 million Florida factory which is oepening this month.'
Telesat put its first prototype broadband satellite in low Earth orbit last year, and is planning on an initial constellation of more than 100 satellites, growing ultimately to 292 spacecraft. to provide first-generation broadband services in the early 2020.
LeoSat Enterprises is planning to launch a constellation of 108 low-earth-orbit communications satellites which they claim will provide the fastest, most secure and widest coverage data network in the world. These satellites will be interconnected through laser links, effectively creating an optical backbone in space which is about 1.5 times faster than terrestrial fiber backbones.
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MANAGING SPACE TRAFFIC and SPACE JUNK
GREATER COOPERATION: The 1967 Outer Space Treaty states that no country may restrict another’s access to and peaceful use of space. According to Marin: 'To adapt to a crowded and democratized space future, we will need some form of space traffic management. The US government is seeking to lead global efforts while developing policies to manage its satellites more effectively. This would not involve ‘traffic police’ directing satellites left or right, but a system more like the weather service. Satellite operators would share information and receive status reports and collision alerts'.See go.nature.com/2dtjznn
In an April 2018 speech, US vice-president Michael Pence announced that the Department of Commerce will take a lead in establishing common global practices to manage space traffic.
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Space is getting crowded. Today, we can track more than 20,000 artificial objects that orbit Earth — including 1,500 working satellites and a plethora of expired craft, used boosters and other debris.'Later this year, ten times as many objects could be revealed when the US Air Force switches on its Space Fence This powerful radar, located on Kwajalein Atoll in the Pacific Ocean and costing US$1.6 billion, will make one million observations a day.' See:go.nature.com/2dxztu3)
IMPROVED TRACKING: 'Tracking space objects is technically difficult, especially if they are small and fast-moving. Objects can be as small as a fleck of paint or as big as a city bus. And most travel many kilometres each second, along orbits from 200 kilometres to 40,000 kilometres above Earth’s surface.
'Currently, the US military uses a website to publish extensive data for objects that are larger than about 10 centimetres (www.space-track.org). However, for every tracked object, there are 20–30 times as many pieces of debris. Most are too small to be followed, but many could end a mission if they were to hit satellite Ultimately, global sharing of tracking data is desirable, to make the best use of sensors around the globe.
The prospects for international cooperation on tracking and management are constrained by geopolitical risks, in that some countries might not want to rely on the United States and would seek their own, independent data.
'This is analogous to the current situation with global navigation and timing data, in which Russia, European nations, China and Japan have all developed some form of alternative to the US-operated Global Positioning System.'
'Under the UN Convention on Registration of Objects Launched into Outer Space, governments are obliged to record new space objects. But this takes weeks or months, and lists are incomplete.
'Governments and companies such as ExoAnalytic Solutions in Foothill Ranch, California, and LeoLabs in Menlo Park, California, are developing services for reporting potential collisions; currently, the US Air Force is the primary provider.'
SPACE DEBRIS SOLUTIONS
The Inter-Agency Space Debris Coordination Committee (IADC), is a group of 13 civil space agencies which has been discussing plans to solve the problem of space debris. They are calling for:
- All satellites in low Earth orbit to be removed within 25 years of the end of their mission
- the elimination of all on-board energy sources — from fuels to spinning momentum wheels — which will lower the risk of decommissioned satellites exploding.
- Some especially hazardous debris objects to be removed from orbit,
RemoveDEBRIS based at the Surrey Space Centre at the University of Surrey in the UK, is aimed at performing key Active Debris Removal (ADR) technology demonstrations to find the best way to capture the estimated 40,000 pieces of space debris that is orbiting Earth. Their website is fantastic, outlined in clear detail the elements of the project and showing video footage of their trials based from the International Space Station, testing capture techniques using a net and a harpoon. See also this BBC report on the project: 'Space harpoon skewers 'orbital debris' by Jonathan Amos [15 February 2019]
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According to 'European Space Junk Cleanup Concept Gets New Mission: Refuel and Repair' by Tereza Pultarova [January 29, 2019] on the Space.com website.
'Envisat, an 8-metric-ton (18,000 lbs.) Earth-observation spacecraft the size of a double-decker bus, failed in April 2012 after a 10-year mission. Due to its size and position in the highly populated low Earth orbit, it is now considered one of the most dangerous pieces of space debris in orbit.'
In December 2018, ESA officials announced their decision to refocus their plans as they were finding it difficult to raise the money for a single-case mission. The new concept of e.Deorbit is to build a multipurpose, in-orbit servicing vehicle that could be used to refuel, refurbish or re-boost satellites.
GENERALIST ARCHIVE: HISTORY OF SPACE JUNK
'Fidel Castro screamed that it was an act of outright agression when a launch from the Cape [Canaveral] misfired and landed on a Cuban farm. Africa received another accidental gift from the Cape; rocket casings strewn across miles of barren country. They raised hell,too.
"But people will just have to get used to the idea that they're going to get hit by falling stages," Schindler said (Schindler is a. rocket expert at Goddard), "just as they're getting hit by falling planes. Fortunately a good proportion of the stages burnt out in the air, but within the next few years spent rocket and satellites are going to start dropping back to earth. Space people are worried about this."
These fragments are already beginning to fall. They're called"decayed objects" because their orbits have decayed as a result of the earth's gravitational attraction which slowly pulls them down. When they reenter the atmosphere, the smaller objects burn up like meteorites. They don't come diving in; they skip in over the upper atmosphere, like a flat stone over water, which gives them time to burn, and gives rise to flying saucer reports featuring Little Green Men. All reports are processed by the Smithsonian Astrophysical Observatory.
It's the larger objects that are the headache; they come down without skipping. One of them smashed into the main street of a town in Manitoba. When experts were called in to find out if it was a meteor, they discovered that it was a chunk of Sputnik IV. The Canadians sent it back to Russia. without thanks.'
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1977
1982
Junk in Space
Man-made debris circling the earth in relatively low orbits
threatens the safety of future space missions
by Donald J. Kessler
[Natural History/March 1982]
'The space age is only twenty-five years old but Earth's orbital space has already been turned into something of a junkyard. About 5,000 man-made objects are currently being tracked in Earth orbit. Only a small fraction of these are functioning satellites that carry such instruments as radiation detectors, atmospheric monitors, commu-nication relays, cameras, and mass spectrometers. Most are either no longer functioning satellites, burned-out rocket stages, or fragments from the breakup of rockets and satellites. No one knows how many additional man-made objects, too small or too high up to be detected, may also be circling the earth. Public attention has largely been focused on the presumed risk that these objects may fall to Earth, causing deaths and physical damage.
For example, when the nuclear-powered Soviet surveillance satellite Cosmos 954 reentered the earth's atmosphere over Canada in 1978, following a sudden depressurization, many feared that it might have spread radiation over that country. None was found, however.
Similarly, there was much consternation in the summer of 1979 when, despite NASA's effort to cause the unmanned Skylab to fall into either the Indian or Atlantic ocean, the spacecraft reentered the earth's atmosphere over Australia. Even though it created a brilliant display in the Australian night sky, nothing on the earth was damaged as Skylab broke up in the atmosphere and pieces of it fell on the continent.
Were we lucky? Not exactly. For purposes of comparison, the risk to humans on the ground is far greater from automobiles, airplane crashes, lightning, and other occurrences.
Every year, between 500 and 1,000 man-made objects reenter the earth's atmosphere from greater altitudes, but most of them are so small that they burn up before hitting the ground.
In any given year, more than 10,000 meteoroids of comparable size, or larger, also enter the earth's atmosphere from outer space, but only about 500 of these become meteorites, surviving to hit the ground. Thus, the risk to people on the ground is greater from meteorites than sixty explosions - some accidental, some planned - that are known to have recurred in space
High-energy satellite explosions, such as that depicted in this painting, are one source of dangerous, small, man-made objects in Earth's orbital space.
[See Previous Post: Curious Facts: Meteorites]
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1977
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1978
A Russian nuclear powered radar spy satellite C954 crashed onto the Northern territories of Canada on January 24th 1978, scattering debris over a 800km area. Its small nuclear reactor disintegrated. Contaminated snow and soil had to be scraped up by bulldozers, put in containers and taken to the Canadian Atomic Energy Board's radioactive waste disposal site.
Soviet radiation across the Arctic' by Marc Montgomery [Radio Canada International]
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| Illustration by William K. Hartmann is a noted planetary scientist, artist, author, and writer. He was the first to convince the scientific mainstream that the Earth had once been hit by a planet sized body (Theia), creating both the moon and the Earth's 23.5° tilt. |
Junk in Space
Man-made debris circling the earth in relatively low orbits
threatens the safety of future space missions
by Donald J. Kessler
[Natural History/March 1982]
'The space age is only twenty-five years old but Earth's orbital space has already been turned into something of a junkyard. About 5,000 man-made objects are currently being tracked in Earth orbit. Only a small fraction of these are functioning satellites that carry such instruments as radiation detectors, atmospheric monitors, commu-nication relays, cameras, and mass spectrometers. Most are either no longer functioning satellites, burned-out rocket stages, or fragments from the breakup of rockets and satellites. No one knows how many additional man-made objects, too small or too high up to be detected, may also be circling the earth. Public attention has largely been focused on the presumed risk that these objects may fall to Earth, causing deaths and physical damage.
For example, when the nuclear-powered Soviet surveillance satellite Cosmos 954 reentered the earth's atmosphere over Canada in 1978, following a sudden depressurization, many feared that it might have spread radiation over that country. None was found, however.
Similarly, there was much consternation in the summer of 1979 when, despite NASA's effort to cause the unmanned Skylab to fall into either the Indian or Atlantic ocean, the spacecraft reentered the earth's atmosphere over Australia. Even though it created a brilliant display in the Australian night sky, nothing on the earth was damaged as Skylab broke up in the atmosphere and pieces of it fell on the continent.
Were we lucky? Not exactly. For purposes of comparison, the risk to humans on the ground is far greater from automobiles, airplane crashes, lightning, and other occurrences.
Every year, between 500 and 1,000 man-made objects reenter the earth's atmosphere from greater altitudes, but most of them are so small that they burn up before hitting the ground.
In any given year, more than 10,000 meteoroids of comparable size, or larger, also enter the earth's atmosphere from outer space, but only about 500 of these become meteorites, surviving to hit the ground. Thus, the risk to people on the ground is greater from meteorites than sixty explosions - some accidental, some planned - that are known to have recurred in space
High-energy satellite explosions, such as that depicted in this painting, are one source of dangerous, small, man-made objects in Earth's orbital space.
[See Previous Post: Curious Facts: Meteorites]
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1983
Screenshot of an Associated Press article that ran in the Ocala Star-Banner, a Florida newspaper, on Jan. 6, 1983.
Source: Business Outsider
1986
Source: New Scientist 13.10.90
Junk in orbit
Dr David Whitehouse
The Guardian 22 August 1986
In July 1982, Space Shuttle Columbia, on its fourth mission, came within 13km of the spent upper stage rocket used to launch the Soviet Intercosmos 4 satellite. Although both objects were being constantly monitored and any possible collision was avoidable, it caused concern to ground controllers.
After the seventh shuttle flight in 1983, one of Challenger's forward windows had to be replaced after it was struck by a tiny speck of paint that had peeled off ' from the satellite.
A few months later, on July 27, 1983, cosmonauts Lyakhov and Alexandrov were working in the Salyut 7 space station when they were startled by a loud crack. Investigation showed that a 0.2 inch diameter crater had been formed on one of the windows. It was too small to puncture the skin of Salyut though it amazingly coincided with preparations for a training exercise called "urgent escape from the station." It is not known if the object which struck Salyut was a natural or artificial piece of space debris.
Some disastrous impacts may already have taken place. The Soviet Cosmos 1275 satellite, launched in June 1981, ceased working after only seven weeks for no apparent reason. Several other satellites are also suspected impact victims.
All objects in space are tracked by the North American Defence Network,
NORAD,...At the latest count there were about 6,000 trackable objects in space of which only 5 per cent were active satellites. Twenty five per cent are dead vehicles such as spent upper stages and used satellites and the rest is debris of various sizes. Most space debris comes from either the accidental or deliberate explosion of satellites.
Between 1973 and 1981 seven Delta rocket upper stages exploded because of a design fault. They showered more than a thousand trackable objects into orbit of which 70 per cent remain.
The Soviet Union has exploded "killer" satellites in space as part of an anti-satellite system.
It is estimated that in total there are 10-15,000 objects of 4 cm or larger in orbit, plus countless smaller objects.
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1987
SATELLITES, BOOSTERS AND DEBRIS with a diameter of 10 centimeters or more swarm around the earth in this computerized printout by Lockheed engineers. Their printout is based on data from the U.S. North American Aerospace Defense Command.
Trashing Space
[Scientific American August 1987]
Early in 1986 a rocket belonging to the European consortium Arianespace roared skyward carrying a Spot 1 satellite. After it had injected the French remote-sensing satellite into orbit, the rocket's third-stage booster itself remained in orbit. Last November, inexplicably, the booster blew up, contributing more shrapnel to an already dense—and potentially dangerous—swarm of objects hurtling around the globe.
At a time when the U.S. is planning to extend its presence in space with a renewed shuttle program, the space station and possibly the Strategic Defense Initiative space technologists are becoming increasingly concerned by the growing cloud of debris that envelops the earth.
The U.S. North American Aerospace Defense Command currently tracks some 7,000 objects about the size of a baseball or larger, most of them working and obsolete satellites and spent rocket boosters.
Four years ago NORAD was tracking only 4,000 such objects, according to Donald J. Kessler of the National Aeronautics and Space Administra-tion. About 40,000 fragmentary ob-jects that are smaller than a baseball and larger than a pea are also in orbit, Kessler says.
A pea-size object colliding with a satellite, a spacecraft or an astronaut at 10 kilometers per second could have the destructive power of a hand grenade, according to Nicholas L. Johnson of Teledyne Brown Engineering.
Even much smaller objects can cause significant damage. In 1984 the space shuttle Challenger returned from a mission with a pit about a centimeter wide in a pane of its windshield. Investigators discovered that the pane, which had to be replaced, had been struck by a paint flake only .2 millimeter wide.
The U.S., says Robert C. Reynolds of Lockheed Engineering and Management Services Company, Inc., "probably has the dubious distinction of creating the most debris" with a series of Delta boosters that exploded during the 1970's.
The U.S.S.R. has contributed with tests of antisatellite weapons and with the de-liberate destruction of malfunctioning satellites.
Members of the International Astronomical Union (IAU), representing current and aspirant space nations, meeting in Washington DC, heard how tiny flecks of waste measuring no more than a postage stamp could cause serious problems for an orbiting satellite or vehicle. Current estimates reckon more than 70,000 pieces of junk are now careering around the earth and the levels, say the scientists, are fast increasing. It seems as old Delta rockets and defunct Intel communication satellites collide they often shatter into fragments which whizz off often reaching speeds of up to 20,000mph.
Dr John Mason, a British physicist, astronomer and consultant to the IAU's debris working party explained:"Just a pound of space junk travelling at say a modest 100mph hits a craft with the force of a 50-ton railway locomotive moving at the same speed."
One scientist who believes he has at least a partial solution to the problem is Professor Kumar Ramohalli, head of Aerospace and Mechanical Engineering at the University of Arizona, in Tucson, USA. He has designed a craft to fly in low Earth orbit, which, he claims, will pick up discarded but useful materials, which a shuttle can collect later, while retrieving true waste for incineration in the Earth's atmosphere.
The device is called an Autonomous Space Processor for Orbital Debris (ASPOD) and Professor Ramohalli, with more then $50,000 in NASA grants, expects the first prototype to be ready early in 1991.
At the heart of the craft are two computers — one controlling a pair of robotic handling arms and the other programmed to recognise structural patterns which look like junk. "You do not want ASPOD up there going around grabbing Russian satellites imagining they are debris. Pattern recognition is very important," explained Professor Ramohalli.
Spreading out from the main body are a series of arms which support reflectors made from gold acrylic. When ASPOD spots debris these reflectors unfurl and incline towards the sun complete with an array of Fresnel lenses which focus the light's infra-red heat onto the junk. "Effectively, they act like powerful solar heat cutters carving up the debris into manageable chunks".
The on-board computers then direct the robotic arms to funnel useless pieces back into a hopper, which, when full, is jettisoned into re-entry orbit for incineration. However, chunks or sheets of useful reflective debris are kept and welded onto the craft's reflector arms.
"ASPOD grows as it collects. The craft starts out at about 2m in width but ends up around 5m processing a piece of junk in about an hour," said the professor. "The arms are a bit like the framework of an umbrella. You have part of the cloth covering it but not the whole lot. The useful pieces are just welded onto the structure for shuttle retrieval."
The unique idea has already aroused the interest of several space nations. Professor Ramohalli admits his invention will not solve the increasing problems of space junk but believes it can play an important role in freeing the heavens from the worst excesses of debris. "It will not be able to handle the really tiny pieces. We expect it to be able to process junk about 10cms in size. However, with collisions occurring all the time adding to the general level of waste, ASPOD can at least help to keep down the rate at which fragments are proliferating", he said.
1990
Columbia will have a safer flight.
Nick Nutall The Times 4.1.1990
To date only one person on Earth is known to have been hit by falling junk. In 1997 Lottie Williams from Tulsa, Oklahoma was strolling in the park when she saw a big ball of fire in the sky. A little while later, something hit her on the shoulder. It turned out to be a small piece of burned mesh from a Delta II rocket. It was like "being hit by an empty drinks can", she said.' She told NPR: "I think I was blessed that it doesn't weigh that much," says Williams, noting that larger pieces of this rocket fell elsewhere. "I mean, that was one of the weirdest things that ever happened to me."
Source: National Public Radio
1987
Trashing Space
[Scientific American August 1987]
Early in 1986 a rocket belonging to the European consortium Arianespace roared skyward carrying a Spot 1 satellite. After it had injected the French remote-sensing satellite into orbit, the rocket's third-stage booster itself remained in orbit. Last November, inexplicably, the booster blew up, contributing more shrapnel to an already dense—and potentially dangerous—swarm of objects hurtling around the globe.
At a time when the U.S. is planning to extend its presence in space with a renewed shuttle program, the space station and possibly the Strategic Defense Initiative space technologists are becoming increasingly concerned by the growing cloud of debris that envelops the earth.
The U.S. North American Aerospace Defense Command currently tracks some 7,000 objects about the size of a baseball or larger, most of them working and obsolete satellites and spent rocket boosters.
Four years ago NORAD was tracking only 4,000 such objects, according to Donald J. Kessler of the National Aeronautics and Space Administra-tion. About 40,000 fragmentary ob-jects that are smaller than a baseball and larger than a pea are also in orbit, Kessler says.
A pea-size object colliding with a satellite, a spacecraft or an astronaut at 10 kilometers per second could have the destructive power of a hand grenade, according to Nicholas L. Johnson of Teledyne Brown Engineering.
Even much smaller objects can cause significant damage. In 1984 the space shuttle Challenger returned from a mission with a pit about a centimeter wide in a pane of its windshield. Investigators discovered that the pane, which had to be replaced, had been struck by a paint flake only .2 millimeter wide.
The U.S., says Robert C. Reynolds of Lockheed Engineering and Management Services Company, Inc., "probably has the dubious distinction of creating the most debris" with a series of Delta boosters that exploded during the 1970's.
The U.S.S.R. has contributed with tests of antisatellite weapons and with the de-liberate destruction of malfunctioning satellites.
1988
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| 'Tracking the scrap metal in the sky' - Paul Mardin. [The Independent 13.6.1988] Illustration by Heath |
Junk spotting in space
[The Times: 30.8.1988]
Nick Nuttall looks at a vacuum cleaner designed to clean up the clutter in space which could otherwise jeopardize launches
The space environment surrounding earth is becoming so cluttered up with junk that guaranteeing the security of vital weather, telecommunications, crop monitoring and navigation satellites may soon prove impossible. Manned space flights, trying to pass through this shroud of discarded and perished rockets, boosters, defunct satellites and other assorted scientific debris, will shortly also become jeopardized. These were just some of the gloomy predictions to emerge from a crisis conference of space scientists and astronomers earlier this month.Members of the International Astronomical Union (IAU), representing current and aspirant space nations, meeting in Washington DC, heard how tiny flecks of waste measuring no more than a postage stamp could cause serious problems for an orbiting satellite or vehicle. Current estimates reckon more than 70,000 pieces of junk are now careering around the earth and the levels, say the scientists, are fast increasing. It seems as old Delta rockets and defunct Intel communication satellites collide they often shatter into fragments which whizz off often reaching speeds of up to 20,000mph.
Dr John Mason, a British physicist, astronomer and consultant to the IAU's debris working party explained:"Just a pound of space junk travelling at say a modest 100mph hits a craft with the force of a 50-ton railway locomotive moving at the same speed."
One scientist who believes he has at least a partial solution to the problem is Professor Kumar Ramohalli, head of Aerospace and Mechanical Engineering at the University of Arizona, in Tucson, USA. He has designed a craft to fly in low Earth orbit, which, he claims, will pick up discarded but useful materials, which a shuttle can collect later, while retrieving true waste for incineration in the Earth's atmosphere.
The device is called an Autonomous Space Processor for Orbital Debris (ASPOD) and Professor Ramohalli, with more then $50,000 in NASA grants, expects the first prototype to be ready early in 1991.
At the heart of the craft are two computers — one controlling a pair of robotic handling arms and the other programmed to recognise structural patterns which look like junk. "You do not want ASPOD up there going around grabbing Russian satellites imagining they are debris. Pattern recognition is very important," explained Professor Ramohalli.
Spreading out from the main body are a series of arms which support reflectors made from gold acrylic. When ASPOD spots debris these reflectors unfurl and incline towards the sun complete with an array of Fresnel lenses which focus the light's infra-red heat onto the junk. "Effectively, they act like powerful solar heat cutters carving up the debris into manageable chunks".
The on-board computers then direct the robotic arms to funnel useless pieces back into a hopper, which, when full, is jettisoned into re-entry orbit for incineration. However, chunks or sheets of useful reflective debris are kept and welded onto the craft's reflector arms.
"ASPOD grows as it collects. The craft starts out at about 2m in width but ends up around 5m processing a piece of junk in about an hour," said the professor. "The arms are a bit like the framework of an umbrella. You have part of the cloth covering it but not the whole lot. The useful pieces are just welded onto the structure for shuttle retrieval."
The unique idea has already aroused the interest of several space nations. Professor Ramohalli admits his invention will not solve the increasing problems of space junk but believes it can play an important role in freeing the heavens from the worst excesses of debris. "It will not be able to handle the really tiny pieces. We expect it to be able to process junk about 10cms in size. However, with collisions occurring all the time adding to the general level of waste, ASPOD can at least help to keep down the rate at which fragments are proliferating", he said.
1990
Columbia will have a safer flight.
Nick Nutall The Times 4.1.1990
The shroud of space debris encirling Earth has fallen for the first time since records have been kept....Recent sun flare activity has played a key role in the purge.1991
Bil Djinis, NASA's project manager for orbital debris said sun flares in the past few months had been among the highest recorded, heating the upper reaches of the earth's atmosphere and causing it to distend and thicken. Consequently, some of the debris just beyond the upperreaches of the atmosphere, including flecks of painty, chips of metal and possibly even a pair of astronaut gloves, have been vapourised.
Figures show that, as of December 29, the number of traceable objects had fallen to 6,697. In 1988 Norad put the level at 7,110 objects.
1997
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Source: National Public Radio
