It appears Earth is down one spacecraft. According to numerous reports in Indian media, contact was lost with the lunar orbiter Chandrayaan-1 abruptly -- in the middle of a communications session with Earth -- at 1:30 Indian time on Friday (Thursday, August 27, at 20:00 UTC). India's communications antenna at Byalalu had received data from the spacecraft up to that taken at 00:25 IST (18:55 UTC), including the results of a recent bistatic radar experiment conducted jointly with Lunar Reconnaissance Orbiter.The Times of India quotes project director M. Annadurai as saying "The mission is definitely over. We have lost contact with the spacecraft. It (Chandrayaan-1) has done its job technically...100 per cent. Scientifically also, it has done almost 90-95 percent of its job."IBNLive reports that S Satish, director of ISRO's public relations, told them "scientists were unable to know what is happening to the spacecraft because of the snag. He said ISRO was not in communication with Chandrayaan 1 and was unable to determine what was happening to the spacecraft after the radio link was lost. 'We are not able to establish communication with the spacecraft--that is what we mean by loss of radio link. It is some sort of serious problem. We are not able to establish communication with the spacecraft, so we are not able to know what is happening to the spacecraft. This anomaly is being analysed from the data received last.'"
Chandrayaan-1 was launched on October 22, 2008 and had been intended to conduct a two-year primary mission. During 312 days at the Moon it orbited more than 3,400 times and returned more than 70,000 images, plus other data. More than half of its instruments were provided by (or in cooperation with) ESA and NASA; several were copies of those on ESA's SMART-1, and one was a duplicate of the Mini-SAR instrument now in orbit on NASA's Lunar Reconnaissance Orbiter. ISRO has posted some images and data from the mission here.
An obvious question seems to be: why did ISRO give up so quickly? It's been less than two days since the loss of contact. I don't have an answer for that.
Many thanks to Svetoslav Alexandrov for the tip and links to Indian news stories.
This is a still from an animation showing how the C1XS X-ray camera on India's Chandrayaan-1 spacecraft used solar X-rays to map the lunar surface. A high-definition version of the animation is available here (Quicktime format, 82.1 MB). Other formats are available here.