Chandrayaan update: 8 instruments functioning, remaining 2 to be activated later this month

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. The two remaining scientific instruments onboard will be activated in mid-December for conducting experiments while the spacecraft orbits over the moon during next two years, a top space agency official said Saturday.

"The sub-kiloelectronvolt (keV) atom reflecting analyser (SARA) and the high-energy x-ray spectrometer (HEX) are scheduled to be activated in mid-December as they need favourable condition from the sun angle. The remaining eight payloads have been energised and are functioning well," Indian Space Research Organisation (ISRO) chairman G Madhavan Nair told reporters in Bangalore on the sidelines of a space conference.

Nair's comments echo those made by SK Shivakumar, director of ISRO's telemetry tracking and command network, who said on 20 November that the spacecraft and the eight instruments activated to date were functioning normally. Five instruments were indigenously built by ISRO, while the remaining six payloads are of foreign origin - three from the European Space Agency, two from the US space agency NASA and one from Bulgaria. (See: Chandrayaan - 1: To the moon, and beyond)

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. (See: Swedish, German and the UK's payloads aboard Chandrayaan-1)

Shivakumar said that both of the orbiter's US 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 US Naval Air Warfare Center in California. It will be used to detect water ice in the permanently shadowed regions at the lunar poles. Rhode Island's Brown University and the Jet Propulsion Laboratory in Pasadena, California jointly developed the mineralogy mapper NASA contributed to the mission. (See: NASA goes back to the Moon, aboard Chandrayaan-1)

An ISRO-built Lunar Laser Ranging Instrument tested for the first time 16 November, 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, said ISRO spokesman BR Guruprasad.

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.

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