GSAT-18, the country’s upcoming communication satellite, has to wait until October in Kourou in French Guiana for launch after its Japanese co-passenger was found damaged days ahead of the launch planned this month.

The 3.4-tonne satellite would have flown into its orbit on July 12 on a European Ariane 5 rocket along with the Japanese spacecraft.

The launch company, Arianespace, deferred the scheduled double-launch after Japan’s Superbird-8 spacecraft reportedly sustained damage.

Arianespace, which ISRO has contracted to put GSAT-18 into space, now has to find a suitable riding mate for the Indian spacecraft from among its other customers.

A.S. Kiran Kumar, Chairman of the ISRO and Secretary of the Department of Space, said: “Originally, the GSAT-18 was scheduled to be launched on July 12. The launch date is now changed because of the co-passenger developing an issue. We will now have the launch more or less in the first week of October.”

Next GSAT-17

The three-month gap would not affect the available national satellite capacity. The next one, GSAT-17, also by Arianespace, is getting ready for blast-off in the first quarter of 2017, Mr. Kumar told The Hindu .

ISRO is developing its own four-tonne launcher, GSLV-Mk3 or LVM-3, to launch communications satellites like GSAT-18.

Health monitoring

Meanwhile, GSAT-18 remains at the Guiana Space Centre while most of the satellite’s engineering support team that accompanied it from Bengaluru has returned. A small team has stayed back to monitor the health of the spacecraft.

Post-launch, GSAT-18 will be positioned at 74 degrees East longitude, where the older INSAT 4CR (launched in 2007) and INSAT-3C (of 2002) are functioning.

According to ISRO officials, it is not uncommon for launch agencies, including ISRO that launches smaller commercial satellites on its PSLV rocket, to reschedule flights when they are putting more than one spacecraft on a single rocket. All satellites flying together must be compatible in many ways beyond size and shape.

Arianespace now has to find a suitable riding mate for the Indian spacecraft from its customers