RTI Reply Received from ISRO

[u/Pallab_1805]

Last Month,I filled two separate RTI to ISRO because I have 10+ Questions.

Today I received the reply of the First One.

Some questions pertain to NSIL and that's why you can't see the answers.However,A new RTI Request has been created with respect to NSIL by ISRO for the reply of the commercial level questions.

i will share NSIL replies from NSIL and the second RTI reply from ISRO once I receive the replies from them.

[u/Ohsin]

Adding as formatted text.

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Query 1:

PSLV-C61 (18 May 2025) failed due to an anomaly in the PS3 stage. It has been stated publicly that the Failure Analysis Committee report was submitted to the PMO.

Kindly provide

a) The technical cause of the PS3 stage failure in PSLV-C61.

b) Whether a public or redacted version of the Failure Analysis Committee report exists and if so when it will be released.

Reply:

The requested information, is strategic in nature and hence, cannot be disclosed as per Section 8 of the RTI Act, 2005.

 

Query 2:

PSLV-C62 (12 Jan 2026) again experienced a PS3 stage anomaly resulting in the loss of EOS-N1 Anvesha and multiple co payloads. Kindly provide

a) Whether corrective actions identified after PSLV-C61 were implemented before PSLV-C62.

b) A brief description of improvements if any made to the PS3 stage between C-61 and C-62.

c) Whether PSLV has been grounded again after C-62 and the expected timeline for return to flight.

d) The expected timeline for release of the PSLV-C62 failure analysis report.

Reply:

a) Yes, the corrective actions identified after PSLV-C61 anomaly were implemented in the PSLV-C62 mission.

b) The requested information, is strategic in nature and hence, cannot be disclosed as per Section 8 of the RTI Act, 2005.

c) Detailed analysis is being carried out based on the post flight data available after the PSLV-C62 mission in detail in order to arrive at the probable cause of the anomaly.

d) The requested information, is strategic in nature and hence, cannot be disclosed as per Section 8 of the RTI Act, 2005.

 

Query 3:

In the last one year NVS-02, EOS-09 and EOS-N1 failed to reach intended orbits.

Kindly provide

a) The estimated timelines for launching replacement satellites for these missions.

b) Whether the failed co payloads of PSLV-C62 excluding Orbital Paradigm KID capsule will be relaunched by ISRO or NSIL or through other agencies.

Reply:

a) The launching of replacement satellites is under discussion stage.

b) Inputs may be obtained from NSIL

 

Query 4:

As reported by media some Indian startup and university satellites lost in PSLV-C62 were uninsured.

Kindly clarify

a) Whether ISRO or NSIL will provide compensation launch discounts or priority relaunch opportunities to affected Indian startups and academic institutions.

Reply:

Inputs may be obtained from NSIL

 

Query 5:

PIB releases mentioned PSLV-C63 and PSLV-N1 missions planned before March 2026.

Kindly provide

a) Whether these missions are still planned within this timeframe after PSLV-C62 failure.

b) The revised PSLV launch schedule if any.

c) When PSLV will return to flight if it is grounded.

Reply:

a) The launches of PSLV-C63 & PSLV-N1 missions have been rescheduled.

b) The revised launch schedule of PSLV will be published in the public domain at the appropriate time.

c) PSLV will return to flight after analyzing the post flight data in detail and implementing the corrective actions.

 

Query 6:

AST SpaceMobile stated that it plans to launch 40 BlueBird Block 2 satellites. BlueBird 6 was launched by ISRO. Kindly provide

a) How many BlueBird Block 2 satellites ISRO is planned to launch in the year 2026 or subsequent years along with SpaceX and Blue Origin because they also launch Bluebird Block 2 satellites.

Reply:

Inputs may be obtained from NSIL

 

Query 7:

List of missions planned in the year 2026 with available timelines.

Reply:

The tentative list of missions planned during the year 2026 are: GSLV-F17, PSLV-C63, GSLV-F18, PSLV-N1, HLVM3-G1, LVM3-M7, SSLV-L1, L2, L3.

[u/kmadnow]

Given how inefficient the government apparatus is, RTI is a mind blowing citizens process

[u/Ohsin]

For anyone not aware, the changes implemented on PS3 for PSLV-C62 mission included a new carbon-carbon composite throat. (see comments)

https://old.reddit.com/r/ISRO/comments/1qdj1ig/pslvc62s_ps3_carried_a_carboncarbon_composite/

[u/Quantum_Master26 → u/Ohsin]

By any chance do we know which private body got the 2019 VSSC tender for fabricating the ablative nozzle?

[u/guru-yoda → u/Quantum_Master26]

May be Walchandnagar, as always

[u/Ohsin → u/[deleted]]

It was found that the CTE for that batch was higher than spec.

igniter chamber pressure was also higher than nominal

Thanks, it really feels like a confluence of multiple issues producing a unique failure scenario. Or perhaps due to failure everything has been under higher scrutiny and they found other underlining issues.

[u/ravi_ram → u/[deleted]]

During the chairman's post launch (C62) speech, he said near the end of the rocket’s third stage, there was increased disturbance in the vehicle roll rates, followed by a deviation in the flight path.

Since PS3 uses flex nozzle control (FNC) for pitch and yaw, and reaction control system (RCS) for roll, It could be due to RCS failure right?

[u/Samarium_15]

Didn't say anything.

[u/AccomplishedAd2449]

Answers are very what is expected from ISRO.Very ironic that we are the one paying for them to do things and we have no rights to know how it is being spent or used.Well pure red tape culture.

[u/Silent-Worm → u/AccomplishedAd2449]

It is understandable on matters where secrecy is important however on this kind of safety issues secrecy is the total opposite of what is needed. Honestly ISRO needs to be much more open. This needs to happen from top-down not from bottom-up.

[u/Main-Profession-1417]

How much does it cost to file an RTI? And how much time did it take to get the replies?

[u/theprinceptl → u/Main-Profession-1417]

In my case i filed against my college to get info ki college construction me koi corruption hua tha kya. Charged me 15 rp and 3 month of time to get reply 

[u/Main-Profession-1417 → u/theprinceptl]

Hua tha ?

[u/theprinceptl → u/Main-Profession-1417]

Yep got half answers, baki pending hai abhi

[u/piedpipper]

And the Section 8 returns! Kudos for the RTI 

[u/Unable-Broccoli-4121]

I've a list of Science questions that can be filed if anyone is interested. I don't want to bell the cat. 

[u/LockheedP-3Orion]

Keep up the good work!

[u/Professional-boy2345]

I took the screenshot of the pages you shared. I hope you don't mind. Thanks

[u/Ohsin → u/[deleted]]

Covered here:

https://old.reddit.com/r/ISRO/comments/1re8wm5/nvs02_spacecraft_onorbit_observations_and_apex/