 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
OK, Our Next Caller Is ... From Mars!
Paris (ESA) Feb 26, 2003 It is midnight on 1 January 2004 and you want to send a greeting on your mobile phone to a friend. Sorry, the line is too busy, try again later. If you think you are alone with this problem, you are wrong. Space agencies have had to work out ingenious solutions to prevent similar 'engaged, call later' tones from happening on Mars. For the first time, there will be seven spacecraft on the Red Planet at the same time. Will they all be able to 'phone home'? Mars is a popular place to go nowadays. ESA's Mars Express mission will be entering orbit around Mars and releasing its lander Beagle 2 at the end of December 2003. The two NASA Mars Exploration Rovers will be landing about the same time. Japan's Nozomi, after five years in space, will be entering Mars's orbit not long after also. Finally, there are two other probes already orbiting the Red Planet: NASA's Mars Global Surveyor and Mars Odissey. What happens if they all try to communicate at the same time? Scientists need to transmit messages continuously to their interplanetary spacecraft. Receiving data concerning the status of the instruments and their results is essential. Since the late 1950s, they use antennas in three NASA stations, which form the Deep Space Network (DSN). The stations are located in Goldstone (California), Madrid (Spain), and Canberra (Australia).
|
