India's moon probe being fitted with instrument suite
Posted: May 28, 2008
Scientists from more than a half-dozen countries are nearly finished shipping parts for six international instruments destined to fly to the moon aboard India's Chandrayaan 1 lunar orbiter later this summer.
About the size of a typical office cubicle, Chandrayaan 1 will carry 11 payloads - five provided by Indian institutions and six supplied by international groups.
Some scientists say Indian officials have privately told them to expect a launch in the third week of August, but representatives of the Indian Space Research Organization could not be reached for comment.
Lunar missions have launch opportunities about every two weeks, each spanning several days around the time the moon's location in orbit crosses near Earth's equator.
Chandrayaan 1 will launch atop a Polar Satellite Launch Vehicle, India's workhorse rocket with a streak of nine consecutive flawless missions.
Most of the hardware for Chandrayaan 1's six international science payloads is already mounted on the craft, currently undergoing testing at the ISRO Satellite Center in Bangalore. Tests to gauge the probe's ability to handle the extreme thermal and vacuum environment of lunar orbit will begin soon, according to Detlef Koschny, project scientist for the European Space Agency's contribution to the mission.
"This is ISRO's first international mission and the first to go beyond the Earth, so they are very keen to get everything right," said Barry Kellett, scientific principal investigator for the C1XS instrument at the Rutherford Appleton Laboratory in the United Kingdom.
C1XS is an ESA-funded payload jointly developed by the U.K. lab, the University of Helsinki and ISRO. Most of the elements of C1XS were delivered to Bangalore earlier this month, but Indian officials are still awaiting the arrival of the instrument's X-ray Solar Monitor, which should begin the trip to India next week, Kellett said.
C1XS will survey the chemical compounds on the moon by detecting the X-ray signature of surface elements. The instrument is derived from a similar science package carried on ESA's SMART 1 demonstration mission that circled the moon for nearly two years until it was deliberately driven into the lunar surface in September 2006.
The deliveries of Chandrayaan 1's five other international instruments began last August, when NASA's Moon Mineralogy Mapper was flown to India from the Jet Propulsion Laboratory in Pasadena, Calif.
Nicknamed M3, the 15-pound imaging spectrometer will map the moon's natural resources through visible and near-infrared wavelengths at higher resolutions than any instrument before. NASA officials hope the device will help them create mineral maps to find science-rich landing sites for future missions, possibly even including human expeditions.
M3 will also look for direct evidence of pockets of water ice hidden inside craters near the lunar poles. Scientists believe there are frozen water deposits deep within the eternally dark craters due to high concentrations of hydrogen found there on previous missions.
A tiny Bulgarian radiation detector called RADOM was transported to India in September and later attached to the side of the spacecraft. The $15,000 instrument will gather data on the radiation environment around the moon, which will be incorporated in the design of future missions.
The German near-infrared spectrometer, or SIR 2, instrument arrived in India for integration and testing in October. The apparatus was bolted to Chandrayaan 1's payload panel in November, according to Koschny.
Built by the Max Planck Institute for Solar System Research and financed by ESA, SIR 2 will cover a narrower spectral band than the M3 instrument to search for search for minerals below the lunar surface. SIR 2 is based on a similar instrument operated in lunar orbit aboard the SMART 1 spacecraft.
Scientists from the Johns Hopkins University Applied Physics Laboratory near Baltimore shipped their radar mapping unit to India in mid-February. The instrument was put on the spacecraft this spring to begin combined testing, a lab spokesperson said.
The MiniSAR payload will bounce radar beams off the lunar surface to look for signs of water ice packed inside the walls of deep craters near the moon's poles. The combination of data from the M3 and MiniSAR instruments will allow researchers to determine how many craters could harbor the frozen water.
Another ESA instrument was delivered to India during the first week of April and connected to the Chandrayaan 1 probe. The 7.7-pound component, called SARA, is made of parts from Sweden, Switzerland, Japan and India, according to Stas Barabash, the payload's principal investigator at the Swedish Institute of Space Physics.
"In my opinion, the progress is very good and the delivery of scientific instruments is about to be completed," Barabash said.
SARA will observe solar wind particles impacting the lunar surface to study the effects of the miniscule particles on the moon's top layer of soil.
ESA provided nearly $8 million to the teams developing the C1XS, SIR 2 and SARA instruments, Koschny said.
India is also wrapping up final testing of five instruments indigenous scientists developed over the past few years.
The instruments provided by Indian scientists include a high-resolution stereo camera capable of imaging objects about 16 feet in diameter. Chandrayaan 1 will also carry near-infrared and X-ray spectrometers and a laser instrument built by Indian science teams. These payloads will help researchers determine the composition and topography of the lunar surface.
Indian engineers also constructed a 64-pound impactor that will be dropped from the orbiting Chandrayaan 1 spacecraft for a suicidal nosedive into the moon. The probe will relay video imagery, altitude information and spectral data back to Earth through the Chandrayaan mother ship.