Late SOS limits Isro’s options

The Indian Space Research Organisation (Isro) was asked to help search for YSR, but the request, says a senior space scientist, came too late. Besides, Indian remote sensing (IRS) satellites have limitations — they cannot track at night, or take pictures through a cloud cover. Isro has three satellites that can do the job — Cartosat-1, Cartosat-2 and the Technology Experiment Satellite (TES).

But the limitations they have mean they satellites can be of use only after sunrise on Thursday. Still, Isro's Hyderabad-based National Remote Sensing Agency (NRSA) pressed a low-flying Beechcraft plane into service on Wednesday.

Indian Remote Sensing (IRS) satellite programme director, M Krishnaswamy, said, “Had the Andhra Pradesh government told us in the morning itself, we would have pressed all three satellites into service to spot the helicopter.”

Of the three satellites, Cartosat-2 is the most sophisticated as it carries a camera with a less than one metre resolution. This means that it is capable of taking pictures of anything larger than a metre. The satellite can also cover 9.6 km at one go.