Spin off to space
IN JANUARY, after a break of 22 years, the US once again turned its attention to the moon. This time, however, it was not NASA that launched a spacecraft, but the Ballistic Missile Defence Organization (BMDO), the successor to the Strategic Defence Initiative Organization.
The spacecraft, christened Clementine, was originally meant to be a technology demonstrator craft to expose advanced sensors, components and computers to deep-space radiation. In its new role, Clementine will orbit the moon for 2 months, clicking pictures of its surface and then re-enter earth orbit for an encounter with an asteroid.
Astronomers say the $80 million mission will advance substantially their understanding of the two celestial objects. The lunar observations will provide a rock map of the moon. Likewise, Clementine will put in sharper focus the make-up of the 1620 Geographos asteroid. On August 31, Clementine will zoom in to within 100 km of the 2 km-by-4 km elongated, rocky asteroid for a 20-minute rendezvous. After the fly-by, Clementine will drift into cosmic oblivion as scientists at the Goddard Space Flight Centre and the Jet Propulsion Laboratory in California glean the data beamed to them.
Destroying asteroids
But the mission has a far more important purpose than just moon- and asteroid-gazing. It is the precursor to evolving a strategy of destroying asteroids that frequently pass perilously close to the earth. The 1908 Tunguska explosion that wiped out a vast Siberian forest is now thought to have been caused by an asteroid bombardment. In 1992, more than 30 small asteroids gate-crashed into the atmosphere, but burnt up before they reached the earth's surface.
BMDO already has Clementine 2 in the pipeline as part of a more ambitious mission that will place four small craft in lunar orbit to fire missiles at earth-bound asteroids. Clementine, armed with the lightest solar cells ever flown and advanced computers capable of handling 25 million instrument readings per second, will provide crucial data on the spaceworthiness of hi-tech sensors and other gadgets.