SPACE• Space is the boundless, three-dimensional extent in which objects and events occur and have relative position and direction.• Leibniz held that space is no more than the collection of spatial relations between objects in the world.
SPACE JUNK• A conceptual artwork representing defunct satellites, failed missions, and shrapnel orbiting a few hundred miles above Earth.• It is the term used to describe man-made rubbish floating in space – often litter from space exploration, including spanners, nuts, bolts, gloves and shards of space craft.
FACTS ABOUT SPACE JUNK• As many as ten million pieces of human-made debris are estimated to be circulating in space at any one time.• Experts believe that global positioning systems, international phone connections, television signals and weather forecasts could be affected by increasing levels of space junk.
FACTS ABOUT SPACE JUNK• The windows of space shuttles are often chipped by space junk when returning to earth.• The majority of the debris in space is believed to consist of small particles but some objects are larger, including spent rocket stages, defunct satellites and collision fragments.
FACTS ABOUT I.S.S.• The International Space Station is fitted with special impact shield known as the Whipple Bumper, which is designed to protect the structure from damage caused by collisions with minor debris.
SOME INCIDENTS• A crash between a defunct Russian Cosmos satellite and an Iridium Communications Inc. satellite in February 2009 left around 1,500 pieces of junk whizzing around the earth at 4.8 miles a second.• A Chinese missile test destroyed a satellite in January 2007, leaving 150,000 pieces of debris in the atmosphere, according to Dr. Gopalaswamy.
• In space, garbage doesn’t just sit there—it hurtles around the globe at extreme speeds.• The more human-made objects whizzing around in this belt, the more likely deadly collisions become.• Current as well as future missions to space will doubtlessly be affected by this lethal band of hyper-fast trash.
• The United Nations Office for Outer Space Affairs (UNOOSA) issued Space Debris Mitigation Guidelines in 2009, urging the removal of spacecraft and launch vehicles from the Earth’s orbit after the end of their missions.• NASA keeps close tabs on at least 16,000 of these objects that are larger than 10 cm in diameter.• The Swiss Space Center at EPFL is launching CleanSpace One, a project to build the first prototype in a family of “de-orbiting” satellites.
Lasers and telescopes now on thedrawing board can slow pieces of loosematerial encircling Earth so that they re- enter the atmosphere.
• Laser orbital debris removal (LODR) as best suited for clearing both large and small debris.• LODR uses the impulse generated by laser ablation of the debris surface by a focused, pulsed ground-based laser to change the debris orbit and cause it to re-enter the atmosphere.• We use a telescope to focus the laser down to a 30cm diameter circle on a target 1000km away.
• RESULTS target during a 2 Getting about 75kJ/m onto the 5ns pulse, which creates a plasma jet.• Slows down small debris items by 10cm/s for each pulse.• Few nanometers of surface are vaporized and the object is not melted or fragmented by the gentle ablation pulse.• At a pulse rate of 10Hz and average power 75kW, the laser can slow targets up to 10cm diameter sufficiently in a single overhead pass that they re- enter the earths atmosphere and burn up, because the amount of slowing required is only about 100m/s.
BENEFITS• An LODR system would provide the lowest cost per object removed.• Target access is at the speed of light, redundant, and agile.• Can handle tumbling objects, while mechanical grapplers cannot.• The system has serendipitous uses aside from general debris clearing, such as preventing collisions.