Satellites—Impact Turn—Debris

Satellites—Impact Turn—Debris

Then, just 30 years after his paper was published, the Kessler Syndrome came into fruition when a defunct Russian communication satellite, the Cosmos 2251, collided with another satellite, Iridium 22, smashing both crafts into an estimated 2,100 pieces that went zipping off into space, each one essentially a bullet waiting for something to come into its path. These kinds of space debris pose a particularly serious threat to active space projects, such as the International Space Station, which could be destroyed by a flying piece of metal as small as 10 centimeters across. Global communication systems are particularly vulnerable to this debris—humans depends quite a bit on satellite activity to make phone calls, use GPS systems, receive television and radio signals, track the weather, and conduct military surveillance. If a satellite carrying any one of these systems were to be hit and damaged or destroyed, it would have pretty serious implications for communications on Earth.

Space debris. Development and use of space for military and civilian purposes over four decades has resulted in a large amount of man-made space debris. Man-made space debris includes dead spacecraft, discarded rocket bodies, launch- and mission-related castoffs, remnants of satellite breakups, solid-rocket exhaust, and frayed surface materials. 65 These artificial objects, along with natural objects (i.e., meteoroids), contribute to the particulate environment of Earth. A collision with even a tiny piece of space debris can damage or destroy a spacecraft, because its approach velocity is very high. The increasing amount of space debris poses a considerable hazard to all kinds of spacecraft, which concerns many Chinese scientists.

Satellites—Impact Turn—Slotting

EOS crowds out sun-synchronous orbits
Williamson 9 (Ray, editor, Secure World Foundation, http://www.imagingnotes.com/go/article_free.php?mp_id=170, accessed 7-2-11, CH)

Collisions with debris are not the only concern, however. As more and more countries launch Earth imaging satellites into orbit, the sun-synchronous orbits that are valued for Earth observations will become ever more crowded, adding another concern to the safety question. As noted in an earlier column (Spring 2008), in July 2007, the orbit of NASA's Cloudsat satellite was shifted slightly to avoid the possibility of colliding with Iran's Singha remote sensing satellite.

Sun-synchronous orbits limited
ERSDAC 10 (Earth Remote Sensing Data Analysis Center, 5/18, http://www.gds.aster.ersdac.or.jp/gds_www2002/seminer_e/e.o.s_e/e.o.s_e.html, accessed 7-3-11, CH)

Satellites are delivered up to the space by a rocket or the space shuttle and placed in flight routes called "orbits". In general, a satellite orbit is an elliptical orbit, which has the earth as one of its focal points. A circular orbit, which is a special case of elliptical orbits, is usually used for earth observation satellites. In this case, the orbit is determined by six orbital parameters: altitude from the ground (altitude), angle of the plane of the orbit against the equator (inclination), time at which the orbit crosses the equator from south to north (ascending node) and so on. Although an infinite number of theoretical orbits exist, geostationary orbits, polar orbits, and sun-synchronous orbits are three major types of orbits most often used for earth observation missions. Selection of an orbit affects the observation area, the recurrence cycle, and the spatial resolution of the earth observation satellite. The maximum latitude of observation areas is determined by the orbit inclination. The recurrence cycle is determined by the orbit altitude. Spatial resolution decreases as the orbit altitude increases because the satellite is farther away from observation targets on the earth.
Sun-synchronous orbits key to spy satellite testing
Clark 11 (Stephen, writer, Spaceflight Now, 2/6, http://www.space.com/10773-secret-spy-satellite-rocket-launches.html, accessed 7-3-11, CH)

The U.S. spy satellite agency hasn't revealed what techniques or sensors the craft will test in space. Its cost, contractor and size are also secret. But the lightweight payload launched on a Minotaur 1 rocket, the smallest booster used by the NRO since the agency's existence was declassified in 1992. The Minotaur's nose cone can fit a spacecraft as large as a kitchen refrigerator, and the four-stage rocket can haul nearly 1,000 pounds into low-altitude polar orbits. "It is an NRO mission using a small rocket, which would denote a lighter payload," Oborn told Spaceflight Now. [Related: U.S. Worried About Outer Space Security] The Minotaur launcher blasted off at 4:26 a.m. local time (7:26 a.m. EST; 1226 GMT) from Vandenberg Air Force Base, Calif. The launch was delayed from Saturday by a transmitter glitch in the Air Force's network of tracking and communications equipment. The six-story rocket swiftly climbed into the predawn sky, breaking the sound barrier seconds later and shedding its powerful first stage a minute after liftoff. Its second stage burned for another minute to propel the rocket nearly 400,000 feet high. Two more Minotaur stages were supposed to accelerate the vehicle to more than 17,000 mph before deploying the satellite. An NRO press release Sunday said the launch was successful. Based on safety information released to mariners and pilots, analysts believe the Minotaur rocket flew south from Vandenberg, dropping its spent rocket motors in the Pacific Ocean and achieving an orbit circling the planet's poles. The Minotaur 1's first and second stages were pulled from stockpiles of decommissioned Minuteman 2 intercontinental ballistic missiles. The smaller Orion 50XL and Orion 38 third and fourth stage motors come from air-launched Pegasus rocket program. Cobbling together unused government-furnished missile stages and commercially-available upper stage motors make the Minotaur rocket family an inexpensive launch solution for defense satellites. The dimensions of the payload's orbit were unknown Sunday morning. The spacecraft could be circling in a polar orbit with a ground track nearly perpendicular to the equator, or the Minotaur could have been aiming for a sun-synchronous orbit commonly used by Earth observation satellites. Other types of north-south orbits were also feasible.

Directory: 2011
2011 -> Enterprise Network Management iPost: Implementing Continuous Risk Monitoring at the Department of State
2011 -> Voices of the Old Sea Norman Lewis
2011 -> Malevil Robert Merle
2011 -> The Elephant Keeper’s Children Peter Hoeg
2011 -> January 1: Ecstasy zZz January 2: King of Anything Sara Bareillis
2011 -> Tracks, Mixes, Masters, and More!: Analyzing Preservation Priorities for Multitrack Recordings
2011 -> Department of Electrical Engineering 2011 Annual Report
2011 -> Jv packet •Mars Colonization Affirmative •Mars Colonization Negative
2011 -> Asian Pacific Mathematical Olympiad(apmo)
2011 -> Registration Form (Rev. 8-86) omb no. 1024-0018

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