ISRO Navigation Satellite Stranded in Transfer Orbit Following Propulsion System Failure

The Indian Space Research Organisation (ISRO) has confirmed that its recently launched NVS-02 navigation satellite has encountered a major propulsion system failure, leaving it stranded in an elliptical transfer orbit and at risk of reentry into Earth’s atmosphere.

Launch and Initial Mission Plan

The NVS-02 satellite was launched on January 28 (Eastern time) aboard a Geostationary Satellite Launch Vehicle (GSLV) Mark 2 rocket from the Satish Dhawan Space Centre in Sriharikota, India.

The mission was designed to deploy the satellite into a geostationary transfer orbit (GTO) with a perigee of 170 kilometers and an apogee of 36,577 kilometers, with the satellite’s onboard propulsion system responsible for raising its orbit to a geostationary position at 111.75 degrees east.

The NVS-02 spacecraft, with a launch mass of 2,250 kilograms, is part of ISRO’s second-generation Navigation with Indian Constellation (NavIC) program, intended to enhance India’s regional navigation and timing capabilities. It was scheduled to replace the aging IRNSS-1E satellite, providing critical services to India and surrounding areas.

Propulsion System Failure

The mission encountered a significant obstacle when ISRO’s attempts to raise the satellite’s orbit failed due to a malfunction in its onboard propulsion system.

“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 Statement

Without the ability to ignite its thrusters, the satellite has been unable to achieve its target geostationary orbit, leaving it stuck in a transfer orbit that poses a risk of reentry.

Data from the U.S. Space Track catalog show that NVS-02 remains in a similar orbit, with a current perigee of 165 kilometers and an apogee of 37,582 kilometers.

Current Status of the Satellite

ISRO noted that other systems on the satellite, including its solar panels, have deployed successfully and are functioning as intended.

“The satellite systems are healthy, and the satellite is currently in elliptical orbit. Alternate mission strategies for utilizing the satellite for navigation in an elliptical orbit are being worked out,” - ISRO Statement

However, the satellite’s low perigee places it within the upper layers of Earth’s atmosphere, where drag could quickly degrade its orbit and result in reentry. If ISRO cannot find a viable solution, NVS-02 may reenter Earth’s atmosphere within weeks, depending on the severity of the drag at its current altitude.

ISRO has not yet confirmed whether any backup propulsion systems are onboard that could raise the satellite’s perigee to a safer altitude.

Mission Implications and NavIC Program

The failure of NVS-02 marks a significant setback for ISRO’s NavIC program, which aims to deploy five second-generation navigation satellites to bolster India’s independent positioning and timing capabilities.

The program’s first satellite, NVS-01, launched successfully in 2023 and is currently operating as planned in geostationary orbit.

The NVS-02 satellite was a key component of the program, intended to replace older satellites and enhance coverage for various applications, including public navigation, military operations, and disaster management.

Possible Recovery Options

While ISRO’s statement suggests that the agency has not completely abandoned efforts to utilize NVS-02, experts believe the chances of recovery are slim without a functioning primary propulsion system.

Some possibilities being explored include using alternative thrusters, if available, or attempting a modified mission profile that leverages the satellite’s current elliptical orbit.

However, even if these options prove feasible, they would likely only provide limited functionality compared to the satellite’s intended performance in geostationary orbit. The primary goal of providing reliable navigation and timing services from a fixed GEO location may no longer be achievable.

ISRO’s ongoing investigation into the failure will be critical not only for assessing the fate of NVS-02 but also for ensuring the success of future launches under the NavIC program.