Chandrayaan I - Update - Technical Snags!!!
Chandrayaan-1, India’s first mission to Moon, launched on October 22, 2008 from Satish Dhawan Space Centre, Sriharikota, has completed eight months of successful operation and has made 3,000 revolutions around the Moon. Besides sending more than 70,000 images of the lunar surface which provide breathtaking views of lunar mountains and craters, especially craters in the permanently shadowed areas of the Moon’s polar region, Chandrayaan-1 spacecraft is also collecting valuable data pertaining to the chemical and mineral content of the Moon. Chandrayaan-1’s orbit was raised from 100 km to 200 km circular on May 19, 2009. The high orbital altitude of Chandrayaan-1 reduces the resolution of the imagery but provides a wider swath and the data is of good quality.
The Prime Objectives:
It may be recalled that the primary mission of Chandrayaan-1 were:
- To realise the complex spacecraft with 11 scientific instruments
- To launch the spacecraft in near earth orbit and to carry out orbit raising manoeuvres of the spacecraft from 22,000 km to 3,84,000 km and place the spacecraft in a circular orbit around the moon
- To place the Indian Tricolour on the moon
- To carry out the imaging operation of the lunar surface and collect data on the mineral content of the lunar surface
- To realise the deep space tracking network and implement the operational procedures for travel into deep space
Click here to View the images of moon sent to earth by Chandrayaan (On ISRO website).Isro chairman Nair said 90 per cent of the mission objectives had been completed and the rest of the work would be pursued over the next four to six months.
Star Sensor Failure !!!
The onboard star sensor used for determining the orientation of the spacecraft started malfunctioning on April 26, 2009. ISRO issued a press release on Friday, July 17 nearly three months after the failure was detected on April 26. It forced the scientists to activate the only back up available!! According to ISRO's official website "To overcome this anomaly, ISRO devised an innovative technique of using redundant sensors – gyroscopes – along with antenna pointing information and images of specific location on the surface of the moon, for determining the orientation of the spacecraft. This method has been validated and based on this information, mission operations are being carried out satisfactorily. Other than the failure of the star sensor and one of the Bus Management Units, health of the spacecraft is normal."
The reason for the sensor malfunction is still
unclear, but it is possible that excessive radiation or particles from the sun disrupted the device, Nair said.
Isro officials also said the shift from the star sensor to gyroscopes was unlikely to cut short the mission. The life of a spacecraft depends on fuel, electronic packages and onboard power systems — not the star sensor.“The information that comes out to us is the same quality as before — it’s just as good,” Barry Kellet, the science investigator for one of the instruments at the Rutherford Appleton Laboratory in the UK, said.
Life till Jan 2010?
Three international space agencies and scientific institutes that have their scientific payloads
on board the moon mission Chandrayaan-1 will be told “unambiguously” to complete their data analyses “at the earliest,” a
senior official at the Indian Space Research Organisation (ISRO) told The Hindu.
In the backdrop of the recent star-sensor failure, the agencies will be given a window till January 2010 to collect all data they need as “they cannot take for granted” that the space craft will complete its two-year tenure, the official said.