Concerns are growing over the status of GalaxEye Space's Mission Drishti, India's first indigenous OptoSAR satellite, amid reports of it tumbling in space and the company's silence on the matter.
Key Points
- GalaxEye Space's Mission Drishti, India's first Made in India OptoSAR satellite, is reportedly tumbling in space after its launch on May 3.
- Experts suggest potential issues with the satellite's solar panel deployment and 3-axis stabilisation as possible causes for the tumbling.
- GalaxEye Space has not commented on the status of Mission Drishti, leading to speculation and concern within the space industry.
- Stabilisation issues are common in earth observation missions and can be resolved with filtering and normalisation models.
Suspense continues as to the status of the world's first Made in India OptoSAR satellite Mission Drishti belonging to Indian space start up GalaxEye Space Solutions Private Ltd that was launched nearly 10 days ago.
Weighing 190 kg, the 2-in-1 satellite -- integrating Electro-Optical (EO) and Synthetic Aperture Radar (SAR) sensors into a single operational platform, enabling all-weather, day-and-night imaging capabilities was launched in space by the US based SpaceX's Falcon 9 rocket on May 3.
While there are reports about the satellite tumbling in space, GalaxEye Space and its Founder and CEO Suyash Singh maintain a studied silence.
On May 7 the company on X announced 'Mission Drishti Update : Contact with the satellite is firmly established.'
On the same day a person who goes under the handle Astro_Neel said: 'So are we all going to just casually ignore the fact that in the publicly available open-source data, anyone can see that Drishti is still tumbling in orbit at the rate of ~3°/sec (or one rotation every two minutes) ever since it was deployed?'
GalaxEye CEO Responds To Concerns
Replying to that on May 8 Singh on X said: 'Love the interest in Drishti. Never saw this level on interest or info floating around on previously launched sats. Also, The date is 3rd May. Can you please share the latest analysis. Also, since you raised this question, Have you ever done a LEOPs (Launch and Early Orbit Phase) of 190 of SAR based Satellite ? Oh oops, you must have worked on a cubesat less than 10 kgs because 190 Kgs in private ecosystem was never launched till date. Hold on buddy, Not everyday these kind of satellites get launched. If something is wrong, we will let the world know. Keep calm.'
Post the satellite launch there was no communication from the company regarding the deployment of solar panels, satellite status and others.
Possible Causes For Satellite Tumbling
"As per the industry grapevine, the satellite's solar panel did not deploy. If the solar panel does not open, it will get power from only one panel which is not enough to drive Reaction Wheels required for maintaining angular stability," says a retired senior Indian Space Research Organisation official, not wanting to be quoted by name for this report.
"If it is tumbling and if the satellite is in a power safe mode and batteries are not being drained, then the tumble can be halted. Preparedness to meet such a situation is the real key to get over the problem. Hope they are prepared," adds another retired senior ISRO official, also preferring not to be identified by name for this report.
Expert Views On Stabilisation Issues
Basing his views on recent media reports about the status of GalaxEye Space's satellite Mission Drishti, former ISRO Deputy Director (Technology & Systems) Dr Mukund Rao says: "Primary stabilisation issues are common in earth observation missions and they do get fixed -- attitude control (AOCS) sensors control is the key system here."
Based on past experience, Dr Rao says one possible issue could be the heating of the infrared horizon sensors or filters. This can happen when the satellite directly faces the Sun while passing over polar regions in orbit.
Such heating may disturb the radiation balance in the infrared sensors, leading to noise and errors in the satellite's pointing and control system.
At times, vibrations and drifting of the payload -- especially since the SAR payload is large -- can become difficult to control, causing blurred images due to unwanted movement or 'tumbling' of the satellite.
Another possible issue could be malfunctioning reaction wheels, though the number of wheels on board is not known. Problems with these wheels can also create drag and affect the satellite's stability.
"All of these and maybe some other issue here have been seen to cause issues in past many global and Indian Remote Sensing satellite missions," Dr Rao points out.
Addressing Stabilisation Challenges
Adding comforting views for GalaxEye Space officials Dr Rao says these issues can be and have been addressed and resolved with filtering and normalisation models for most problems.
"Like in IRS-1A, I think it took 2 or 3 months for perfecting the 3-axis stabilisation," Dr Rao adds
Confident that GalaxEye Space will be working intensely on the 3-axis stabilisation and the satellite 'tumbling' issue Dr Rao says if the 3-axis stabilisation is not achieved, it creates a cascade of failures that can start with power issues, battery depletion and putting the mission to jeopardy.
In case the solar panels were not deployed, it is doubtful if they can be deployed if the satellite is 'tumbling', Dr Rao says.
Dr Rao is of the view that Indian space satellite start ups need experienced people and there are many retired ISRO officials whose knowledge could be tapped.
The Indian National Space Promotion and Authorisation Centre (In-SPACe) should also assist GalaxEye Space, he says. IN-SPACe instead of restricting its role to granting permission/promotion/licensing should also take steps to enable, strengthen and build the Indian space sector.
Despite several attempts, GalaxEye Space's Founder and CEO Singh declined to comment on Mission Drishti's status.
Venkatachari Jagannathan can be reached at venkatacharijagannathan@gmail.com
Feature presentation: Mahipal Soni/Rediff
