Chandrayaan-1 Success Makes India Fifth to Reach Lunar Orbit

U.S., European Instruments Join India's Unmanned Moon Mission

Circling the moon in a polar orbit 100 kilometers (62 miles) above the battered surface, India’s first lunar spacecraft, Chandrayaan-1, ancient Sanskrit for “lunar craft,” is also an international venture that carries instruments from the United States and Europe.

The two-year unmanned mission launched October 22 from India’s spaceport at Satish Dhawan Space Centre in Sriharikota and entered lunar orbit November 8. India became the fifth nation to send a spacecraft to the moon, after the United States, the former Soviet Union, Japan, China and the European Space Agency’s 17-country consortium.

According to the Indian Space Research Organisation (ISRO), mission objectives are to use high-resolution remote sensing in a range of frequencies (visible light, near infrared and low- and high-energy X-rays) to create a three-dimensional moon atlas and map the lunar surface for distribution of minerals and chemical elements like magnesium, aluminum, silicon, calcium, iron, titanium, radon, uranium and thorium.

Moon Impact

On November 14, one of Chandrayaan-1’s 11 instruments, the 35-kilogram (77-pound) moon impact probe, ejected from the spacecraft and took a 25-minute trip to the lunar surface, hard-landing near the south polar region.

The probe carried images of India’s tri-colored flag, now resting in the moon’s dusty regolith (surface cover), and three instruments. On the probe’s way to the surface, a radar altimeter measured its altitude, a video imaging system took photographs of the moon and a mass spectrometer measured parts of the extremely thin lunar atmosphere.

The rest of the instruments – four developed by India, two through NASA and four through the European Space Agency (ESA) – are being used sequentially, ISRO says, and lunar exploration has begun.

“The instruments here have managed to send back 35,000 images so far,” the unofficial Chandrayaan-1 Twitter feed announced December 30 at Twitter.com, a Web site that lets users send short text messages from their cell phones. “The data has been labeled as ‘good’ by ground,” Chandrayaan-1 added.

International Payload

India’s contributions to the spacecraft instruments include a terrain-mapping stereo camera to map the moon’s topography, a hyper-spectral imaging camera to help map the moon’s mineral distribution, a lunar laser-ranging instrument to determine the difference in height between the spacecraft and the lunar surface, and a high-energy X-ray spectrometer to detect radioactive emissions from the surface.

Collaboration between ISRO and ESA members produced two instruments – the Chandrayaan-1 X-ray spectrometer (with the United Kingdom) to study the moon’s origin and evolution, and an atom-reflecting analyzer (with Sweden) to image the moon’s surface composition and surface interactions with the solar wind.

ESA and Germany’s Max Planck Institutes provided a near-infrared spectrometer to survey mineral resources for future landing sites and exploration, and the Bulgarian Academy of Sciences provided a radiation dose monitor experiment to measure the radiation environment in near-lunar space.

NASA’s contribution includes a mini-synthetic-aperture radar (mini-SAR) developed by the Johns Hopkins University Applied Physics Laboratory in Maryland and funded by NASA, and the Moon Mineralogy Mapper (M3) built by Brown University in Rhode Island and NASA’s Jet Propulsion Laboratory in California.

First Moon Map

The M3 is a state-of-the-art imaging spectrometer that will help produce the first map of the entire lunar surface at high spatial and spectral resolution, showing the minerals that make up the moon’s surface.

“M3 is going to look for minerals on the moon’s surface to try to figure out the geologic history of the moon,” M3 Program Executive Anthony Carro told America.gov, “and understand the evolution of the moon and the terrestrial planets” – the rocky planets Mercury, Venus, Earth and Mars – in the early solar system.

A detailed map of lunar resources, possibly including water, will be useful to astronauts who may live and work on the moon and for those who may use the moon as a way station for longer journeys into space.

Finding water ice will be an objective of NASA’s other Chandrayaan-1 instrument, the mini-SAR, a small imaging radar that will map the moon’s permanently shadowed lunar polar regions, including large areas that are never visible from Earth.

The mini-SAR “is a precursor to an advanced technology system” built for NASA’s Lunar Reconnaissance Orbiter mission, scheduled for launch April 24, 2009, Michelle Gates of the Mini-SAR Management Team told America.gov.

“It was a pretty challenging opportunity in the sense that ISRO wanted a suite of instruments, including a radar instrument for mapping, but they had a pretty tight mass requirement to meet,” the team’s Jason Crusan told America.gov.

Scientists from the Applied Physics Lab submitted a proposal for the system and worked with ISRO scientists for about 26 months on technology development, he said.

Multiple Steps

Earlier moon missions – the Clementine lunar mapping mission in 1994 and the Lunar Prospector mission in 1998 – gave initial indications of lunar water ice, the team’s William Marinelli told America.gov, and the mini-SAR will offer “a more detailed mapping of those areas to ensure that we understand what’s there.”

Mini-SAR data will be used to determine the location and distribution of water ice deposits and help scientists learn about the history and nature of objects hitting the moon and the processes that throw material from the outer solar system into the inner planets.

NASA is also providing space communications support to Chandrayaan-1, mainly from the NASA ground tracking station at the Applied Physics Lab.

“This is the first time we’ve ever worked on a mission together” with India, Crusan said, “but hopefully it will be the first step in multiple steps to come.”

Story by Cheryl Pellerin.

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