Most of Chandrayaan-1’s Instruments Up and Running
Chandrayaan-1 is sending scientific data to Eart through India's Deep Space Network antenna (shown being installed) in Byalalu, about 30 kilometers from Bangalore.
Credit: ISRO photo

BANGALORE, India ? With India's Chandrayaan-1 lunar probe settled into a stable orbit 100 kilometers over the Moon?s poles, eight of the 10 scientific instruments on board the spacecraft have been powered on and tested at least once, a senior official of the Indian Space Research Organisation (ISRO) told Space News Nov. 20.

The $86 million Chandrayaan-1 mission was launched Oct. 22 by ISRO's Polar Satellite Launch Vehicle from Satish Dhawan Space Centre in Sriharikota on the southern coast of India. It entered lunar orbit Nov. 8 and is expected to study the Moon for two years.

S.K. Shivakumar, director of ISRO's telemetry tracking and command network, said Nov. 20 that the spacecraft and the eight instruments activated to date were functioning normally.

Of the two remaining instruments, a high-energy X-ray spectrometer built by India was slated for activation within a matter of days, Shivakumar said, while a Swedish-built imager would not be turned on until Dec. 5 per the request of the instrument's principal investigator.

Shivakumar said the latest instrument powered on as Chandrayaan-1's flight controllers were heading into the weekend was an X-ray spectrometer developed by Rutherford Appleton Laboratory in the United Kingdom. "We tested it for some time and it is functioning normally," Shivakumar said. The instrument will use an X-ray fluorescence spectrometry technique to measure the Moon's elemental composition.

The previous day, Chandrayaan-1's flight controllers switched on a near-infrared spectrometer developed by Germany?s Max-Planck Institute for Solar System Science. The instrument will help determine the chemical composition of the lunar crust.

Shivakumar said that both of the orbiter's U.S. payloads ? the Miniature Synthetic Aperture Radar and Moon Mineralogy Mapper ? also had been tested and that their "initial data looked good."

The synthetic aperture radar was developed jointly by the Johns Hopkins University Applied Physics Laboratory of Laurel, Md., and the U.S. Naval Air Warfare Center in California. It will be used to detect water ice in the permanently shadowed regions at the lunar poles.

The mineralogy mapper NASA contributed to the mission was jointly developed by Rhode Island's Brown University and the Jet Propulsion Laboratory in Pasadena, Calif.

An ISRO-built Lunar Laser Ranging Instrument tested for the first time Nov. 16, sends pulses of infrared laser light toward a strip of lunar surface and detects the reflected portion of that light. Data from this instrument will help prepare an elevation map of the Moon, ISRO spokesman B.R. Guruprasad told Space News Nov. 20.

The map will be used for studying the morphology of large basins and other lunar features of the Moon's polar and equatorial regions, he said. The information when coupled with gravity studies will help researchers determine the density distribution of the crust, he said. The instrument, which will be continuously operated, takes 10 measurements per second and provides range information to an accuracy of less than five meters.

Three other instruments that have been working continuously since being activated before Chandrayaan-1 reached lunar orbit are the Terrain Mapping Camera and the Hyper Spectral Imaging camera, both built by ISRO, and the Radiation Dose Monitor supplied by the Bulgarian Academy of Sciences. Data from the Bulgarian experiment will be used for the evaluation of the radiation environment and the radiation shielding requirements of future manned Moon missions, ISRO officials said. "After reaching lunar orbit, the Terrain Mapping Camera has been taking breathtaking pictures of the lunar panorama," Guruprasad said.

A 34-kilogram impactor probe emblazoned with the Indian national flag and ejected from Chandrayaan-1 Nov. 14 toward the lunar surface served dual purposes by symbolically marking India's arrival on the Moon and testing technologies for future lunar landings.

The pictures and other scientific data Chandrayaan-1 is sending back to Earth are being received by the Indian Deep Space Network at Byalalu about 30 kilometers from the Satellite Control Centre at Bangalore.

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