Earlier today the Indian Space Research Organization tersely announced that radio contact with its lunar orbiter, Chandrayaan 1, was "abruptly lost" at 1:30 a.m. local time. Reports from Indian news organizations suggest uncertainty among ISRO officials about the craft's fate, though recovery seems unlikely.

Chandrayaan 1 carries 11 instruments, three of which were supplied by the European Space Agency and two by the United States. Launched last October 22nd, the spacecraft had completed some 3,400 orbits since becoming a lunar satellite on November 8th. An assortment of results (mostly images) is posted here.

The craft also released a small instrumented probe that struck the Moon's south polar region on November 14th.

India's first lunar orbiter was designed to last two years. But those prospects dimmed in mid-July when the spacecraft lost its star sensor, critical for maintaining orientation. Yet ISRO officials remained upbeat, claiming that 90% to 95% of the mission's objectives had been met.

In fact, just a week ago Chandrayaan 1 participated in a special exercise that might prove to be its final scientific triumph. On August 21st Chandrayaan 1 directed its transmitter toward the lunar north pole, and NASA's Lunar Reconnaissance Orbiter recorded the reflected pulses of radio energy. Changes in the reflected signal's character could indicate the presence of water ice in permanently shadowed craters near the pole.

August has become particularly unlucky for lunar orbiters and their attitude-control systems. On August 22nd, NASA's Lunar Crater Observation and Sensing Satellite (LCROSS) experienced a sensor malfunction that triggered unchecked thruster firings.

By the time ground controllers declared a "spacecraft emergency" and restored control, LCROSS had lost half of its hydrazine fuel. Project engineers estimate that about 125 pounds (50 kg) of fuel remains — enough, they say, to carry out the craft's planned self-destruction when it strikes the Moon on October 9th.