Fire off: ISRO’s GSLV-F08 carrying GSAT-6A communication satellite blasts off from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh | PTI

It was a textbook launch. As the GSLV rocket took off from the second launch pad at Sriharikota at 4.56pm on March 29, watchers on the rooftop gallery clapped. The International Space Research Organisation immediately began releasing updates, even a video from the on-board camera, showing details of the flight that was carrying a communication satellite—GSAT-6A. The updates continued till April 1, when ISRO announced the successful second orbit raising operation, carried out on March 31. The next orbit raising was to happen shortly afterwards, which would insert the satellite into the orbit it was destined for. But, after the flurry of updates, an ominous silence followed. ISRO finally confirmed it lost communication with the satellite on April 1. The satellite was on the last leg of its journey when the communication snapped.

The announcement created ripples in spacefaring circles across the globe. ISRO, with its series of successful and record-breaking launches and missions in recent times (low-cost moon and Mars missions, the latter being the first by any country in its maiden attempt, as well as the record-making 104 satellites in one launch) is a major player in spacefaring. Its launches are watched keenly. Coming months before Chandrayaan 2, an ambitious attempt at sending a rover to the south pole of the moon, this mission failure has raised a question—will the slated missions get postponed? There is also Aditya, a mission to study the sun, in the pipeline.

ISRO has not lost all hope yet. Its chairman K. Sivan said efforts are still on to reestablish contact with the satellite. Realists know that while finding GSAT-6A is not impossible, keeping the hope alive is a “consolation”. If it happens, it will be a wonder, said A. Sivathanu Pillai, honorary distinguished professor, ISRO. “What is more important is to understand that such things happen in every space programme,” said Pillai. “While it is not a happy event, it should not have any impact on the next planned missions. ISRO has a busy calendar this year. It is moving onto heavier launches, and we have got to move on.”

While it is still too early to say what went wrong, it is clear what did not go wrong. The GSLV Mk II rocket, the biggest and heaviest in ISRO’s present stable, which carried the payload, cruised just fine. This is crucial, because a GSLV Mk II rocket will be used to ferry the Chandrayaan 2 payload this year end. Also, this was the sixth flight with the indigenously developed cryogenic stage. So, there is no fault in that department, either. This flight was also testing the indigenously developed, liquid-fuelled, high thrust Vikas engines, to give additional boost at takeoff. These are an improvement on previous Vikas engines, and are expected to be incorporated on all future Mk II flights. Though everyone is tightlipped now, it does seem that the rocket, with all the added technological components, has passed the test. It is only the satellite that has gone rogue.

ISRO has had a good track record, though there are setbacks everywhere. The present one is disappointing, as it comes within weeks of the new chairman taking over. It also comes within six months of the disastrous PSLV launch last September, when the rocket’s heat shield failed to separate and the mission failed in inserting the navigation satellite into orbit. The PSLV failure was a setback, since its track record was near perfect with only one of its 40 missions since 1993 having failed previously.

Other space agencies, too, have had their share of misses, though many go underreported. The most recent one was the African nation Angola’s maiden space venture, Angosat-1, which was launched on December 26 last year from Baikonur in Kazakhstan, by Russia. Soon after launch, the satellite lost contact with its ground stations. The next day, however, scientists reestablished contact with it, and on December 29, Roscosmos even announced that Angosat-1 was in good health. But, a few days later, the North American Aerospace Defense Command (NORAD) detected that the satellite was “drifting”, and by mid January, it had gone beyond its “operational point” in space. On January 15, Moscow-based RSC Energia said that the telemetry showed that the satellite had problems with the power supply system. But, by then, it had drifted beyond the range of ground control stations, so there was no way to do any troubleshooting. Scientists have calculated that sometime in April, the drifter could come under the range of the ground controls again, and they could have another shot at bringing it under control. Till then, Angola’s space dream remains nebulous. The satellite was the culmination of years of effort, and had a life of 15 years. It was meant to improve communications in the country.

Even more curious is the case of another lost and found satellite, NASA’s IMAGE. It was launched in 2000 to map the sphere of gases around the earth. For five years, the satellite diligently did its work, sending a trove of images to its handlers on earth. In December 2005, it stopped sending images. NASA concluded that the power supply subsystems had failed, and nearly forgot about IMAGE.

But then came Scott Tilley in 2018. Tilley, whose hobby is radio astronomy, was trying to find NASA’s stealth satellite Zuma, which had failed, similar to the ISRO one, and was wandering somewhere in space. Tilley had no telescope, he just followed radio signals, like they do in the movies. And, on January 20, he heard a strange signal, which he initially did not bother about, till he heard it again. Some quick research, and he was stunned to realise he had found the lost IMAGE. NASA later confirmed the find and even announced that “it has been able to read some basic housekeeping data of the spacecraft, suggesting that at least the main control system is operational”.

So, what happened to IMAGE? One theory states that its systems hanged, like it happens with mobile phones. And, just as with mobiles, you first have to drain the battery to reset the system; IMAGE, too, went through a battery draining phase. Then, the solar batteries recharged again, and the satellite arose from slumber.

The game of peek-a-boo between satellite and ground centre can stretch on for years. So though GSAT-6A remains invisible for the present, who knows when the radars at Byalalu (Karnataka) might catch it! Que sera sera, they say.