Tuesday, July 22, 2008
THE LANDING OF a spacecraft on Eros, an asteroid in deep space, is truly a magnificent achievement for more than one reason. Launched by the Applied Physics Laboratory of the Johns Hopkins University, the spacecraft Near Earth Asteroid Rendezvous (NEAR), is the first cosmic probe launched by a non-NASA (the U.S. National Aeronautic and Space Administration) outfit. It is the first time that a space vehicle has landed on an asteroid which should give it a grandstand view of the star- spangled universe. And it is not exactly a ``near Earth rendezvous'' as it has been called since Eros is quite far away at a distance of 165 million miles. The Earth-based manoeuvring which has gone into the steering of the spacecraft should have been highly intensive and brilliantly executed to enable it to catch up with the asteroid which should have been extremely difficult even if it had only been moving at high speeds. The movements of all asteroids and the directions they take unlike those of planets are highly irregular and the landing of NEAR virtually turns out to be a trapping of Eros into the service of space scientists.
Sir Arthur Clarke who is globally known for his studies of space exploration had actually regarded such a rendezvous which he called ``interplanetary hitch-hiking'' almost as an impossibility in his Greetings, Carbon-Based Bipeds. Such hitch-hiking has now turned out to be a reality and the space vehicle it has left on Eros could have a piggyback ride on the asteroid which would continue to meander in space as it has been doing for several million years. The landing of the space vehicle on Eros should immensely enrich the knowledge about what is going on with its beaming of data to Earth-based stations from the asteroid. The landing of NEAR on Eros also provides an occasion to recall the potential hazards which were foreseen by space scientists earlier. Asteroids of varying shapes and sizes - mostly of rocks - range from those which are quite a few hundred miles in width to those much smaller. The possibility of asteroids moving wildly in space and straying into Earth's orbit to hit the planet with a destructive ferocity is no longer deemed as unlikely. Such hits had taken place earlier and one of them is said to have snuffed out the hardy dinosaurs which roamed over the Earth for as long as 150 million years ago to black out the planet from the Sun under several million tonnes of dust. Such a catastrophe is now being foreseen for the Earth during the next century from a comet heading towards it. The defensive measures being considered for averting the catastrophe envisage the deflection of the comets or asteroids away from the Earth. The NASA had set up a committee in 1994 headed by Dr. Eugene Shoemaker to draw up a plan to identify and catalogue possible collisions of comets and asteroids with the Earth. Such a collision had already taken place within the solar system itself when the comet christened as Shoemaker-Levy had crashed on Jupiter and the cosmic disaster was captured in a remarkable live telecast. It is learnt that such near misses, known and unknown, are already said to be taking place. Direct hits by these asteroids would spell doom and could litter the Earth with craters like the one left in the Gulf of Mexico by an asteroid-hit a few million years ago
The landing of NEAR on Eros should throw more light on asteroids which are not just space jetsam and should initiate further studies on how they came into being. However, unlike in the case of the moon from where soil samples were brought to Earth by astronauts, access to the geology of asteroid rocks million of miles away can only be through hi-tech space probes. Space scientists have in fact already gained such access to just as far away Mars and discovered that it has water in its poles.