It was a moment reminiscent of September 2019.
Barely minutes after the Indian Space Research Organization (ISRO) fired up its latest innovation – a Small Satellite Launch Vehicle (SSLV) on its maiden flight — the excitement paved way for dismay.
The two experimental satellites – EOS-02 and AzaadiSAT — developed by hundreds of schoolgirls from across India hurtled towards the earth shortly after their launch from Sriharikota, and was rendered unusable.
The new-generation rocket that was expected to demonstrate India’s capacities in ready-to-launch missions could not achieve the target it aimed for.
ORBIT GONE WRONG
“Irrespective of the number of missions undertaken in the past, the last point at which the rocket leaves the satellite in space is crucial and challenging, every single time. The accuracy has to be on point, in terms of the location, velocity, as well as the direction. Even if it varies a little bit, the entire trajectory of the satellite can go haywire and disrupt the entire mission,” a senior astrophysicist told News18.
The point at which the glitch occurred is automated in the rockets, but the calculations inserted have to be precise and well-controlled. According to the scientist, one of the components may not behaved reliably, and such issues can be hard to predict, post successful ground tests. But with the ISRO gearing up for much more ambitious missions, including Gaganyaan — India’s first human spaceflight, in the near future, even the smallest of glitches could prove to be costly.
Most communication and remote sensing satellites are placed in low earth orbit at a height of 250-2,000 km, and can either have a circular or elliptical orbit depending on the mission requirements. For the latest mission, ISRO had aimed for a circular orbit of 356 km, but it ended up in an elliptical orbit of 356 km x 76 km, which essentially means that the point at which the satellite is closest to the earth is 76 km, which is believed to be the lowest, and unable to hold the satellite for long.
ISRO chief S Somanath put it down to an “anomaly in placement of satellites in the destined orbit”, which was perhaps caused by the rocket’s automated response after it detected a sensor failure in the system. “It identified a sensor failure, and went for the salvage option. This means, that the system had a deficiency, which we need to look at carefully,” he said, post the launch.
The senior aerospace engineer, who took over the top role at ISRO early this year, said, “The performance of the SSLV was good. It took off majestically, and all stages separated well on time.”
The performance of the third stage, which had to propel the rocket from 336 km to 356.5 km, was also stated to be ‘normal’. But in the terminal stage, soon after the liquid fuel-based velocity trimming module (VTM) atop the rocket cut off after placing the satellite in orbit, a data loss was detected and payloads did not respond.
According to the ISRO chief, except this anomaly, every other element in the rocket performed very well, be it the lift off, aerodynamics, control systems, and the entire architecture.
SETBACK FOR COMMERCIAL MISSIONS?
While ISRO has already begun the damage-control to analyse the anomaly, and look for ways to rectify it, it has definitely left the space agency short of a dream start to its SSLV project. The much-awaited launch was expected to put India’s space capabilities on the global stage as a preferred go-to destination for commercial launches of small satellites.
The low-cost rocket was designed for flexible launch on-demand capabilities that could be readied with minimal launch infrastructure requirements. “It should not be looked as a setback for the entire project,” says Chaitanya Giri, a Space Tech Consultant with Research and Information System for Developing Countries (RIS).
“The glitch was perhaps not with the rocket, but with the telemetry of necessary data in the terminal stage. The data was missing, and the satellites could not reach the target orbit. Although it also seemed as if it did not accelerate as much as it should have after the two stages separated. If it was due to some external factors, we do not know. But such glitches can be rectified,” he opined.
With the first demonstration of SSLV rendered unsuccessful, the agency will now get down to the task of identifying and correcting the anomaly, and then gear up to take another shot at it very soon.
While the glitch may appear minor, or even ‘hard to predict’, it still stands pertinent, especially at a time, when ISRO aspires to take the giant leap with Gaganyaan.
The premier space agency stands at a crucial juncture of expanding its operations on the global stage, through its commercial arm, IN-SPACe, and undertaking most ambitious missions till date.
After a long delay due to the pandemic, agencies across the world are racing to leverage their commercial space capabilities.
With the market for small satellites launches set to grow, any mission, big or small will remain crucial.