Clementine 1 - Mission to Near Earth Asteroid Geographos

The Clementine 1 probe is best known for being the probe which first discovered water at the Moon's poles.

Clementine 1 was a very low budget probe paid for by the U.S. Department of Defense's Ballistic Missile Defense Organization (BMDO) (previously known as the Strategic Defense Initiative (SDI), aka "Star Wars").

What is less known is that Clementine 1 headed off for a rendezvous with near-Earth asteroid 1620 Geographos, which makes a very close approach to Earth periodically.

Unfortunately, Clementine 1 failed en-route to Geographos. A software bug in its star tracking navigation system misled the probe to think it was improperly oriented. The software had insufficient fault tolerance in that the probe suddenly started spending a lot of fuel in endless reorientation attempts. The software should have put limits on how much fuel it could expend, at the very least. There are several mission critical "system fault tolerance" algorithms that should have been built in to prevent what happened. Instead, it just went on spending all its fuel, and by the time mission controllers on the ground were notified, it was out of fuel and could no longer rendezvous with Geographos.

A subsequent probe, Clementine 2, which would have visited multiple near Earth asteroids, was approved by Congress. Objectives included analyzing the dynamic strength of surface material, crater formation, dust cloud composition, stratification, thermal properties, and of course spectral data for composition and mechanical properties. Leading targets under consideration were asteroids 1987 OA, 1989 UR, and 1991 JX. Clementine 2 was a joint venture between the U.S. Air Force Space Warfare Center, Phillips Laboratory and NASA.

In 1997, when the controversial U.S. President's "line item veto" was first exercised, one of the first two things cut was the mere $20 million annual appropriation for Clementine 2, in a highly public political display of the line item veto being used to delete wasteful public spending for allegedly ridiculous projects. Of course, Clementine was at a cost equal to about one military aircraft, so we could continue to fight over Earth's limited resources. Tells you a lot about the selfish and nearsighted nature of human political mobs. Given the need for Near Earth Asteroids for space colonization in view of human extinction risks, this may eventually go down in history as a bigger event than the Lewinsky affair (another issue of human folly) as regards Clinton's image. For all his exceptional high intelligence, his basic stupidity will be the tall pole in the tent.

Since Clementine didn't do anything as regards asteroids, the main PERMANENT article on Clementine 1 is in the section on lunar probes. Clementine is famous for having been the first to discover water ice at the lunar poles, which has created strong interest in mining the lunar poles. There is also more interesting sociopolitical commentary on the Clementine mission in that section:

Clementine 1 and lunar water ice

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