Bengaluru: The satellite Isro launched in its much-celebrated 100th launch mission on Jan 29 has suffered a failure of a valve designed to supply oxidiser to the liquid apogee motor (LAM) onboard the spacecraft, multiple sources have confirmed to TOI.
Now, the space agency has been unable to operate LAM, which is critical for the spacecraft to change orbits and reach its intended orbit for operations. As of Sunday, the satellite continues to remain in a geosynchronous transfer orbit (GTO), which is an elliptical orbit used to insert satellites before they are moved to their intended final orbits.
Navigation satellites need a near-circular orbit to operate optimally, and without the firing of LAM, that will be difficult for Isro to achieve. “The issue with the valve was detected after the launch put the satellite in GTO. Orbit- correction manoeuvres have not been carried out since launch,” a source said.
Another source pointed out that the valve was “not opening” as it was intended to, “preventing LAM from getting the supply of the oxidiser, without which the motor cannot be fired”. The source added that multiple attempts to resolve the issue have not been able to get the “desired outcome”.
A third source said a committee looking into the issue has met multiple times in the past four days and that a final decision on how to operate the satellite may be taken soon. “All other systems on the spacecraft are fine. It is fully healthy, there’s full electrical generation and we are able to control the satellite,” the source said.
Other sources said the space agency may consider operating the satellite from an available orbit, but a final decision on the same was pending. “We are able to exploit the signal,” one of the sources said.
The NVS-02 satellite is part of Indian Regional Navigation Satellite System (IRNSS) with an operational name NavIC, or Navigation with Indian Constellation. It is part the second generation of NavIC satellites and carries an indigenous atomic clock.
Hours after TOI contacted Isro chairman V Narayanan for comment Sunday, Isro issued an official statement: “Subsequent to the launch, solar panels on board were successfully deployed and power generation is nominal. Communication with the ground station has been established. But the orbit raising operations towards positioning the satellite to the designated orbital slot could not be carried out as the valves for admitting the oxidiser to fire the thrusters for orbit raising did not open.”
The satellite systems are healthy and it is currently in elliptical orbit. “Alternate mission strategies for utilising the satellite for navigation in an elliptical orbit are being worked out,” the Isro statement added.
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GLITCH SURFACES IN HOURS
■ Isro’s GSLV-F15 lifts off with NVS-02 satellite at 6.23am on Jan 29
■ Around 19 mins later, satellite placed in a geosynchronous transfer orbit
■ Just a few hours later, glitch in valve detected
■ Valve to supply oxidiser to LAM engine doesn’t work as intended
■ Without oxidiser, Isro unable to fire LAM, perform orbit corrections
■ Isro forms committee to address the issue; multiple meetings held
■ Satellite still in GTO, Isro weighing options, final decision pending