"The unique bi-static experiment was carried out jointly when Chandrayaan and Orbiter came closer while orbiting over the lunar North Pole where the permanently shadowed crater is located," the state-run Indian Space Research Organisation (ISRO) said in a statement here.
Indian space scientists will analyse the data received from NASA's miniature radio frequency instrument on board Chandrayaan and the Orbiter to ascertain the existence of water and ice in the permanently shadowed crater.
"Chandrayaan transmitted the signals and the Orbiter received the reflected signals through the instrument, which functions as a synthetic aperture radar (SAR). The four-minute experiment used both the radars to point at Erlanger Crater at the same time," the statement said.
Prior to the experiment, the Orbiter made a minor manoeuvre to adjust its orbit to that of Chandrayaan, located 200 km above from the lunar surface.
The experiment was conducted at 00:30 IST from the spacecraft control centre of ISRO telemetry, tracking and command network (Istrac) at Peenya, 20 km from this tech hub.
The data was soon downloaded from the Orbiter at Johns Hopkins University's Applied Physics Laboratory (APL) in the US, the ground station that had the visibility.
A few hours later, the Indian Deep Space Network (DSN) antennas at Byalalu, about 40 km from Bangalore, also received the same data along with Chandrayaan's orientation information while bi-static observations were made.
"ISRO and NASA scientists will analyse the observational data from the experiment to find out whether water is present in the form of ice on the dark lunar surface in the crater, which is away from sunlight," the space agency added.
Chandrayaan was launched amid fanfare October 22, 2008, from India's only spaceport Sriharikota, about 90 km north-east of Chennai, onboard the 316-tonne polar satellite launch vehicle (PSLV-C11) and inserted into the lunar orbit Nov 8. A week later, its moon impact probe (MIP) was crashed into the lunar surface Nov 16.
The 11 scientific payloads onboard the lunarcarft continue to send high quality data as per planned sequence to its ground station (DSN).
The mooncraft has orbited around the moon 3000 times over the last nine months and its high-resolution cameras relayed over 70,000 digital images of the lunar surface, providing breathtaking views of mountains and craters, including those in the permanently shadowed area of the moon's polar region.
Of the 11 scientific instruments (payloads), five are Indian. Of the other six, three are from the European Space Agency (ESA), two from the NASA of the US and one from Bulgaria.
