Indian Navigation Satellite Stuck in Transfer Orbit

Eight days ago as I write, Jan. 28, the Indian Space Research Organization (ISRO) launched their version of a navigational satellite called NVS-02.  Their Geosynchronous Satellite Launch Vehicle (GSLV) Mk II lifted off at 7:53 p.m. Eastern Standard Time (0053 UTC) from the Satish Dhawan Space Centre. 

As is common in satellites above the lowest, easiest to achieve orbits, once the launch vehicle delivered the NVS-02 payload to the desired deployment altitude, an engine onboard was then set to fire to transfer the satellite to the desired orbit.  On Sunday Feb. 2 the ISRO announced that due to a thruster failure on the satellite it was unable to reach its intended orbit. 

According to a statement posted on ISRO’s website but not otherwise publicized by the agency, “the orbit raising operations towards positioning the satellite to the designated orbital slot could not be carried out as the valves for admitting the oxidizer to fire the thrusters for orbit raising did not open.”

 ISRO goes on to say:

The satellite systems are healthy and the satellite is currently in elliptical orbit. Alternate mission strategies for utilising the satellite for navigation in an elliptical orbit is being worked out. 

The big problem facing the satellite is that it's in an orbit that's unstable.  The Space Track catalog maintained by the U.S. Space Force shows that the satellite remains in an orbit with a perigee of 165 kilometers and apogee of 37,582 kilometers.  That perigee is barely over 100 miles and that's a height where atmospheric drag is a concern, especially in periods near solar max as we are now in.  Solar storms can make the atmosphere expand which can increase drag a lot.  Remember back in 2022 when a solar storm cost SpaceX 40 out of 49 satellites it had just launched?  Those satellites had a perigee of approximately 210 kilometers, almost 50km higher than this one (or 130 miles) - and that wasn't even a strong solar storm. 

Later in the day Sunday ISRO posted to X:

The main Liquid Apogee Motor (LAM) engine on the satellite remains in an unusable state, which is why ISRO is now going to attempt to use its Attitude Control System thrusters to slightly raise its perigee.

Any satellite with a perigee below 200 km is in a highly unstable orbit. The current perigee of NVS-02 is at 170 km.

ISRO will probably attempt to raise the perigee only somewhat above 200 km to put NVS-02 in a more stable orbit. It is highly doubtful whether they will be able to raise it all the way into a circular GSO orbit (which was the original destination).

The NVS-02 navigation satellite with its payload fairing before being encapsulated ahead of its Jan. 28 launch. Image credit: ISRO