Updated on Sunday, November 16, 2008, 00:00 IST

Bangalore, Nov 16: The Lunar Laser Ranging Instrument (LLRI), one of the 11 payloads carried by the Chandrayaan-1 spacecraft, was successfully turned on Sunday when it was passing over the western part of Moon's visible hemisphere.

Preliminary assessment of data from the LLRI by scientists indicates that the instrument's performance is normal, an ISRO statement said.

The LLRI sends pulses of infrared laser light towards a strip of lunar surface and detects the reflected portion of that light. With this, the instrument can very accurately measure the height of Moon's surface features.

The instrument will be continuously kept on and is taking 10 measurements per second on both day and night sides of the Moon. It is also providing topographical details of both polar and equatorial regions of the Earth's satellite.

Detailed analysis of the data sent by the LLRI helps in understanding the internal structure of the Moon as well as the way that celestial body evolved.

It may be recalled that earlier, three payloads of Chandrayaan-1 -- Terrain Mapping Camera (TMC), Radiation Dose Monitor (RADOM) and Moon Impact Probe (MIP) -- were successfully turned on.

The MIP, carrying the Indian tricolour, was released from the spacecraft on November 14 and 25 minutes later, successfully impacted the lunar surface as intended. TMC took pictures of the Earth and Moon when the spacecraft was on its way to Moon.

The statement said that TMC has been taking breathtaking pictures of the lunar panorama. The RADOM was also switched on in the earth orbit itself, it added.

The pictures and other scientific data sent by Chandrayaan-1 from the lunar orbit have been received by antennas of Indian Deep Space Network (IDSN) at Byalalu on the outskirts of the city.

The spacecraft operations are being carried out from the Satellite Control Centre (SCC) of ISRO Telemetry, Tracking and Command Network (ISTRAC) at Bangalore.

Bureau Report