When Isro launched 10 sats in one go

The Indian Space Research Organisation’s (Isro) success in putting into orbit five satellites on June 30, 2014 in a single launch has a precursor that is more complex and spectacular.

In April 2008, Isro created history launching 10 satellites in one go. While the latest Isro rocket carried satellites weighing 765 kg, the rocket in 2008 carried satellites weighing 860 kg.

The experience of successful launching of multiple satellites in one go was achieved in 1999, when for the first time, Isro launched three satellites — two foreign ones and an Indian satellite.

The Polar Satellite Launch Vehicle (PSLV) then undertook several multiple launches, but the 10-satellite launch happened for the first time in 2008. Post that launch, the most significant launch is the latest one that carried five satellites, all foreign.

Isro had earlier carried out exclusive launches of foreign satellites, but they were just two or three. The June 2014 launch is the first exclusive launch of five international satellites in one go.

In the April 2008 launch, the PSLV rocket launched India’s own 690 kg CARTOSAT-2A and an 83 kg Indian Mini Satellite (IMS-1) apart from eight nanosatellites, all from abroad together weighing about 50 kg. The rocket took in all 1,151 seconds to complete the launch. The nanosatellites were built by universities and research institutions in Canada and Germany. The critical aspect of the launches is the precision of ejection of the satellites. The timing for the ejection of satellites one after the other is programmed and pre-determined. In this latest launch, each satellite was ejected every 30 seconds. In all, the ejection time worked out to 150 seconds. Since Isro had undertaken the 1999 and 2008 launches, it was well placed to undertake the June 2014 launch.

For Isro, this feat could be historic, but then the space agency as its scientists themselves say will have to learn to launch over 30 satellites at one go to be a world-beater. That’s because the Russian space agency launched 37 satellites in one launch recently. It can be argued, however, that the launch was on a de-fused intercontinental ballistic missile, which has power that rivals a rocket. But the point of the launch was to show operational success.

Isro has caught up with at least some Russian technology, and its scientists say that the launch of over 35 satellites is well within Isro’s capacity. The history of learning from foreign missions and from its own mistakes has been a remarkable feature of Isro, and in almost all cases of failure, the space agency has come up with success in the following missions. The April 2008 launch was followed by India’s first moon mission, Chandrayaan-1, which, in October 2008, saw an India spacecraft crash-landing on the moon’s surface for the first time in the country’s space history. 

The challenge in launching multiple satellites is to ensure that the satellites are placed precisely in the intended orbit, not just in outer space, in which case, the satellite would fall towards earth or get lost in space. Isro’s development in the technique is one reason for other countries choosing India’s space agency for launches.