Laser payload aboard Chandrayaan turned onNovember 16th, 2008 - 8:59 pm ICT by IANS
Bangalore, Nov 16 (IANS) The lunar laser ranging instrument (LLRI) on board India’s first unmanned spacecraft Chandrayaan-1 was switched on Sunday, two days after the moon impact probe (MIP) landed on the lunar surface.”The instrument was turned on when the spacecraft was orbiting over the western part of the moon’s visible atmosphere. Initial data indicated the instrument’s performance is normal,” the Indian Space Research Organsiation (ISRO) said here in a statement.
The laser payload sends pulses of infrared laser light towards a strip of lunar surface and detects the reflected portion of that light. The wavelength of the light emitted is 1,064 nm (nanometre, which is one billionth of a metre).
The instrument also accurately measures the altitude of the spacecraft from the lunar surface and the moon’s surface features.
The instrument will be kept on to take 10 measurements per second on both day and night sides of the moon. It also provides topographical details of both polar and equatorial regions of the moon.
“Analysis of the LLRI data helps in understanding the internal structure of the moon, the way the celestial body evolved over millions of years and the way its large surface features changed over time,” the space agency said.
The pictures and the data transmitted by the spacecraft from the lunar orbit are received by the antennas of the deep space network (DSN) at Byalalu, about 40 km from this tech hub.
The spacecraft operations are carried out from the satellite control centre of the space agency’s telemetry, tracking and command network (Istrac) on the outskirts of Bangalore.
Built by ISRO’s laboratory for electro-optic systems in Bangalore, LLRI is the fourth of the 11 scientific payloads onboard Chandrayaan, orbiting 100 km above the moon’s surface.
Earlier, the terrain mapping camera (TMC), built by ISRO’s Space Applications Centre in Ahmedabad, and radiation dose monitor (RADOM) of the Bulgarian Academy of Sciences were switched on while Chandrayaan was on its way to the moon, about 384,000 km from the earth.
The TMC has been taking breathtaking pictures of the lunar panorama.
The 11 payloads onboard Chandrayaan include five designed and developed in India, three instruments from the European Space Agency, two from the US and one from Bulgaria.
“Chandrayaan will use high resolution remote sensing in the visible, near infrared, microwave and X-ray regions of the electromagnetic spectrum to map the moon over the next two years. It will enable preparation of a 3-D atlas of the lunar surface and help map it chemically,” the statement noted.
The high resolution imaging will help in understanding the process of lunar evolution. The data from LLRI will help in understanding of the moon’s gravitational field as well.