Saturday, August 29, 2009

Mission Chandrayaan-1 ended today !

At 01:30 today, ISRO has lost contact with the Chandrayaan-1 spacecraft orbiting the moon. Chandrayaan-1 was launched on 22nd October 2008 and carried 11 instruments on board including 5 Indian and 6 foreign instruments. The total cost of the mission was 386 crore.
According to ISRO Chandrayaan-1 has done its job technically 100% and scientifically 90-95%. Chandrayaan-1 has completed 312 days in orbit, making over 3400 orbits around the moon.
But the mission was scheduled to be of 2 yr duration and it could last only 10 months.
Currently ISRO is conducting a detail review of the telemetry data of the spacecraft to find the cause of the problem. In April 2009, the star sensor of the Chandrayaan-1 spacecraft has developed a malfunction and failed. The star sensor was responsible for determining the altitude of the spacecraft and for orientation. ISRO has been able to overcome the malfunction using antenna-pointing mechanism and on board gyroscopes.

Friday, August 21, 2009

Isro-Nasa to look for water on Moon in tandem

Chandrayaan-1 launched by ISRO is currently orbiting the Moon in search of water and ice. It is going to be joined by LRO (Lunar Reconnaissance Orbiter) launched by NASA on 18th June,2009. Together the satellites will do some really interesting study. The spacecrafts will fly at a velocity of around 1.6 km per second and survey an area on the north pole of the Moon.
Generally a single satellite sends a signal to a spot of observation and picks the signal reflected back. But in this case, the radars of the spacecrafts will point to the same spot from different angles, such that the reflected signal sent by one can be picked up by the other.The radar instrument on board Chandrayaan-1 i.e. Mini-SAR will send signal pointed to the interior of the Erlanger Crater. The signal will get reflected from the crater and will be picked up by Mini-Rf radar on board LRO. Mini-SAR will also collect the signal reflected straight to it. Then scientists can compare the signal obtained from the oblique reflection to that obtained from the straight reflection for study. This type of experiment is called as Bi-Static radar experiment.
It is really challenging to put 2 space-crafts in orbit of the Moon and then coordinate them for such missions. The challenge increases when the spacecrafts are being designed, developed and deployed by 2 different organizations. But it is a good move by NASA and ISRO to combine their effort for such research activities.

NASA page on the experiment.