Isro postpones GSAT-11 launch, recalls satellite to re-check performance

GSAT-11 was planned to be launched mid-May, the satellite had reached Arianespace's rocket port in French Guiana in March

The Indian space agency has recalled its communication satellite GSAT-11 from Arianespace's rocket port in French Guiana for further tests, to be on the safe side, said Indian Space Research Organisation (Isro) chairman K Sivan on Wednesday.

"We are bringing back the GSAT-11 satellite to carry out some tests to be doubly sure of its performance orbiting in the space. There is nothing more to it," Sivan told IANS.

He said the satellite is expected to be back in India on April 5 or 6, and after the tests and checks, GSAT-11 can be back in Ariancespace's rocket port in Kourou.

"Due to additional technical checks with the Indian Space Research Organisation's GSAT-11 satellite, to be conducted from the Isro Satellite Centre (ISAC) located in Bengaluru, the Ariane 5 launch initially planned for May 25, VA243, has been postponed," Arianespace had said.

The GSAT-11 was planned to be launched mid-May. The satellite had reached Arianespace's rocket port in March.

GSAT-11 was designed, assembled and integrated by the Isro, and will have an estimated lift-off mass of 5,870 kg.

This advanced communications satellite is to provide multi-spot beam coverage over the Indian mainland and nearby islands, bringing significant advantages to the user community when compared with India's existing INSAT/GSAT satellite systems, Arianespace said earlier in a statement.

With its new system architecture and cutting-edge technology elements, GSAT-11 will generate a capacity of more than 12 Gbps for users from a single platform, the statement added.

The Isro's move to call back GSAT-11 for further tests and be doubly sure of its performance may be due to the loss of the recently launched GSAT-6A satellite, soon after it was put into orbit on March 29.

Isro suspects the failure of the power systems in the satellite for the loss of communication link.

"The satellites are powered by solar panels that charge the onboard batteries. The batteries are fully charged when the satellite is loaded on to the rocket.

"Even if there is a problem with the solar panel, then the battery power should have kicked in. Here the entire power system of the satellite seems to have failed," one space expert told IANS earlier.

According to experts, the power system could have failed due to some short-circuiting or arcing resulting in what is known in the space terminology 'loss of lock' or loss of contact with the ground station.

Satellites in space are locked to ground stations for tracking and other purposes.

On March 29, Indian rocket Geosynchronous Satellite Launch Vehicle (GSLV) slung GSAT-6A in its intended orbit. From there the satellite was to be taken up further to its orbital slot by firing its onboard motors.

The first orbit raising operation was successfully carried out by firing the onboard motors for around 36 minutes on March 30 morning.

The second orbit raising operation of GSAT-6A satellite was also successful as its motors was fired for about 53 minutes on March 31.

After that, the communication link got snapped.

Industry experts also said there has been instances where communication link with satellites got reestablished after a break of couple of days.