Cartosat-1 (IRS-P5) was the first Indian remote-sensing satellite able to take stereo images from orbit. Launched in May 2005, its two 2.5 m cameras were used to make 3D maps of the ground.
Cartosat-1 carries two black-and-white cameras, one tilted forward by 26 degrees and one tilted back by 5 degrees. Each sees 2.5 m detail over a 30 km strip. Because both cameras photograph the same ground moments apart from two angles, the pairs can be turned into elevation models and accurate 3D maps.
It weighed 1,560 kg at launch. A 15 square-metre solar array gave 1,100 W. A 120 Gb solid-state recorder stored pictures until a ground station came into view. It was designed for five years.
PSLV-C6 launched Cartosat-1 with the small HAMSAT on 5 May 2005. It was the first launch from the Second Launch Pad at Sriharikota.
It flies in a sun-synchronous polar orbit about 618 km high, crossing the equator at about 10:30 am local time. It can revisit an area every five days, and its ground track repeats every 126 days.
The public satellite catalogue still carries Cartosat-1 with an operational flag. That flag is not confirmation from ISRO that a satellite designed for five years is still working two decades after launch, so treat its current status as unconfirmed.