While the space elevator faces a number of significant engineering challenges that need to be overcome before it gets built, the Space Elevator Journal has focussed on challenges that will occur once it's up and running. The issue of space debris, natural and man-made, will be a constant of life in space. Unfortunately, most of the man-made junk is in Low-Earth Orbit (LEO).
Millions of people have lived on Earth for thousands of years but, considering the few humans that have been in space, there may be more garbage per person in space than on Earth.
The link in the title of this post points to a flash animation from the European Space Agency (ESA) that is as compelling as it is disturbing. It shows the accumulation of space debris from the Sputnik launch in 1957 until the year 2000. Earth disappears from view in the mid-1970's.
The ESA's European Space Operations Centre (ESOC) runs a space debris program that explains since October 4th, 1957, more than 4,200 launches have lifted some 5,500 satellites into orbit but only approximately 700 are still operational. This unconscionable waste may be the best single reason for getting a space elevator built and ending Earth-based rocket launches forever.
On 21 January 2001, this 70 kg titanium motor casing from a PAM-D (Payload Assist Module - Delta), reentered the atmosphere over the Middle East landing about 240 km from the Saudi Arabia capital of Riyadh.
Source: NASA Orbital Debris Photo GalleryAccording to SOCRATES, the free daily service that predicts the probability of orbital close encounters between satellites and the thousands pieces of debris orbiting Earth, today (/2007/01/02) at 15:32:01.539 UTC Cosmos 489, an old Russian satellite launched in 1972 and SL-8 R/B, a Tsyklon Stage 2 rocket body (launched in 1979) will pass within 0.054 kilometers (177.2 feet) of each other at a relative velocity of 14.225 km/sec (31,820 mph !!!). Allowing for reasonable margins of error means there's a distinct chance these two pieces of space junk will collide (and possibly explode if there's residual fuels, batteries or other volatile materials involved) scattering chunks all over LEO endangering operational satellites and the humans that depend on them.
Orbital debris in LEO*
- 95% junk -
Source: NASA Orbital Debris Program Office
Ironically, both objects are from the Tsiklon program, the first prototype Soviet navigation satellite system but that is only one potential collision among Several large pieces of space debris re-enter the atmosphere every month according to the Aerospace Corporation, a US space R&D centre.
Did it ever occur to you to wonder how many of the satellites have nuclear power sources on board and if any of them have ever decayed back into the atmosphere and/or crashed to Earth? Stay tuned to the Space Elevator Journal.
--PB--
* LEO - Low Earth Orbit: the region of space within 2,000 km of the Earth's surface. It is the most concentrated area for orbital debris.
On 21 January 2001, this 70 kg titanium motor casing from a PAM-D (Payload Assist Module - Delta), reentered the atmosphere over the Middle East landing about 240 km from the Saudi Arabia capital of Riyadh.
Source: NASA Orbital Debris Photo Gallery
Source: NASA Orbital Debris Photo Gallery
Orbital debris in LEO*
- 95% junk -
Labels: Space debris, Space elevator, space environment
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