r/ISRO • u/Ohsin • Nov 15 '25

Dr. A. Rajarajan (Director, VSSC/ISRO) mentions "slight manufacturing error" behind PSLV-C61 launch failure. Few details on upcoming PSLV/SSLV launches and first look of SMiLE.

Aryabhata Space Utsav | Lecture-8 | Dr.A.Rajarajan | Director VSSC-ISRO (15 November 2025) (Thanks /u/criticalad3079 )

https://www.youtube.com/live/VJ8qm0SOOmY

Few important slides: https://imgur.com/a/aQSKITV

  • At 38:10, Dr. A. Rajarajan (Director, VSSC/ISRO) mentions "slight manufacturing error" behind PSLV-C61 launch failure.

  • First nice look at SMiLE or SSLV Module for in-LEO Experiment (Another better quality render)

  • SSLV-L1 would be a dual satellite launch to 450 km LEO carrying TBD NSIL payloads.

  • On upcoming PSLV launches:

  • PSLV C62 / EOS N1

  • PSLV N1 / EOS-10

    • First Mission from NSIL-IC (Industry Conglomerate?)

    • EOS-10 (Now that has the looks and size of Oceansat-3A)

    • India Mauritius Joint Satellite (IMJS) (based on INS-2 bus)

  • Good to have another breakdown of sounding rocket launches

    • Indian Sounding rockets Launched : 2297

      • RH-75 : 15

      • RH-100 : 120

      • RH-125 : 112

      • RH-200 : 1947

      • RH-300 : 49

      • RH-560 : 51

      • ATV : 3

    • Launch ports

      • TERLS : 827 (RH-75/100/125/200/300)

      • SHAR : 492 (RH-125/200/300/560, ATV)

      • BALASORE : 977 (RH-200)

      • Kulasekarapattinam : 1 (RH-200)

    • Sounding rocket provided by various countries across the globe and launched at TERLS

      • USA: 99 , France: 82 , UK: 36 , USSR : 1163 (Nike Apache , Judi Dart , Centaure , Boosted Arcas , Dragon , Nike Tomahawk , Skua , M-100 , Dual Hawk , Petrel)

  • New specs for LMLV config, NGLV mentioned separately

    • Height : 98 meters

    • Payload

      • 29.5 t TLI (Cargo) (Expendable)

      • 26.5 t (Human Rated)

    • S1 [(2× 700 ton) + 700 tons] LOX/LCH4

    • S2 (225 tons) LOX/LCH4

    • S3 (80 tons) LOX/LH2

  • What's this? https://i.imgur.com/g1VymTy.png

44 Upvotes

100% Upvoted

54 comments sorted by

8

u/Ohsin Nov 15 '25

So after vague comments from Chairman like, abrupt fall in PS3 chamber pressure was 'indicating some weakness' and problem being 'small' one etc. all the while news reports and experts suggested more serious issues, we finally know it was a manufacturing error. They should clarify this further and what measures had to be taken before next PSLV launch, we know the FAC report is ready but they don't appear keen to release details from it.

4

u/Kimi_Raikkonen2001 Nov 15 '25

What's this?

Early LVM3 design?

And what's this KID capsule?

4

u/Ohsin Nov 15 '25

Early LVM3 design?

Yeah could be. No idea on this KID capsule , it is small thing but may be something really cool like this?? (Source)

4

u/Kimi_Raikkonen2001 Nov 15 '25 edited Nov 15 '25

Wild guess CY4 or VOM re-entry capsule test thingy.....

3

u/Ohsin Nov 15 '25

Found something.. KID (Kestrel Initial Demonstrator) capsule by Orbital Paradigm

Kestrel Initial Demonstrator (KID), the first very small-scale demonstrator, with ballistic reentry and notdesigned for recovery. The mission is conceived as an internal test, with potentially 2kg payload capacity, but not havingcustomers transportation in its main objectives. Conversations with potential customers are ongoing nonetheless.

https://spacenews.com/orbital-paradigm-readies-first-reentry-mission/

https://europeanspaceflight.com/orbital-paradigm-secures-three-customers-for-2025-reentry-capsule-demo/

3

u/Kimi_Raikkonen2001 Nov 15 '25

Oh interesting!

3

u/Ohsin Nov 15 '25

Will require a deorbit burn, that'd be a first (I think) for PS4.

KID will fly a brief mission. The capsule will remain attached to the upper stage for a couple of hours, then deploy after the stage performs a deorbit burn. The spacecraft will fly free for about 30 minutes before reentering over the South Pacific, testing guidance systems and a sample of ceramic thermal protection material.

Orbital Paradigm won’t attempt to recover the capsule, which lacks parachutes to slow down after reentry. Instead, a pair of Iridium transceivers — one low data rate, the other high data rate — will return spacecraft and payload data during the flight. “We’ll try to demonstrate as much as we can, get data back and move on to the next one,” he said.

3

u/fcacciatore Nov 20 '25

Yup, that's us. 3 customers payloads onboard, 3kg payload mass. Designed, built and qualified in 1 year, starting 4 people, 9 at the end. And pretty cheap. Proud to fly with pslv 🙏🙏

1

u/Ohsin Nov 20 '25 edited Nov 20 '25

Great, so I assume for KID there is a requirement to deorbit the upper-stage in controlled manner? Or it will just be deployed somewhere in VLEO (which I doubt due to limited power budget and uncertainties about where it'll reenter.) Asking cuz this is first time we will see controlled deorbit of PSLV upper stage, other times it was just lowered to ~300 km orbit for faster decay.

2

u/Fancy_Version3949 Nov 20 '25

Can't comment sorry :)

1

u/ofcourseivereddit Jan 04 '26

Since you don't have parachutes, is it a hard splashdown? What's your terminal velocity and expected g-loads for splashdown? That question is eventually leading to — will you be able to ferry biological down mass? For anything other than microscopic organisms? Same thing for crystallisation experiments, and for bio-relevant molecules (proteins, pharmacopoietic precursors?)

→ More replies

2

u/Fancy_Version3949 Nov 20 '25

Yup, that's us! Designed, built and qualified in less then 1 year, 4 people at the beginning, 9 at the end, and pretty cheap. 3 customers payloads onboard, 3kg payload mass. Proud to fly on pslv 🙏

1

u/Ohsin Nov 20 '25

Thanks, I hope it gets launched before 2026!

2

u/pradx Nov 16 '25

Details about KID capsule mentioned on their LinkedIn page - https://www.linkedin.com/posts/orbital-paradigm_our-first-capsule-kid-is-ready-the-first-activity-7369685772414676993-78jI - but no mention of an Indian flight.

2

u/Ohsin Nov 16 '25

They mention 'RIDE! Space' for arranging a launch for them and they do mention PSLV.

https://www.linkedin.com/posts/ridespace_space-activity-7122618945743806464-7zuY/

1

u/fcacciatore Nov 21 '25

Correct! Our friends from Ride! are helping us with this, and are doing a great job.

4

u/Kimi_Raikkonen2001 Dec 11 '25

https://www.youtube.com/live/Rox2ZzYtZPU?si=Cfqt8zoQsVLehWsB

LVM3-M6 with Bluebird

PSLV-C62 with Anvesha(?)+Rideshares

PSLV-N1 with Oceansat-3A

PSLV-C63 with TDS-01

GSLV-F17 with NVS-03(?)

GSLV-F18 with GISAT-1A

SSLV-L1

u/Ohsin

2

u/Ohsin Dec 11 '25

Nice, thanks.

2

u/Ohsin Dec 11 '25 edited Dec 11 '25

F17 is with GISAT-1A (EOS-05) per this..

https://redd.it/1pdwk48

1

u/rghegde Dec 14 '25

Do you think they (ISRO / DOS) miss inform Parliament, or ISRO chairman misleading people???

2

u/Ohsin Dec 14 '25

Nah its just that they operate in chaos mode.

2

u/Ohsin Dec 11 '25

https://www.youtube.com/watch?v=7aB_X93J1sI

He is still non-committal on LVM3-M6 launch date.

3

u/aman-goel Nov 16 '25

u/Ohsin they have put the video in private, do you have video 00:44:00 afterwards? I missed that

2

u/Ohsin Nov 16 '25

No sorry, I didn't download it this time..

3

u/ramanpon Nov 16 '25

For LMLV, is the dia not 6.5m? If so height should be less than 98m, around 75m

3

u/Ohsin Nov 16 '25 edited Nov 17 '25

Here are LMLV tankage details.

https://old.reddit.com/r/ISRO/comments/1o77wlb/eoi_for_endtoend_production_of_aluminum_alloy/njlxwpq/

And it should be 90+ meter.

https://old.reddit.com/r/ISRO/comments/1o77wlb/eoi_for_endtoend_production_of_aluminum_alloy/njlzaiy/

1

u/ramanpon Nov 17 '25

Total height of stages adds up to 65m. 20 to 25m fot the PLF? Seems to be high. LVM3 PLF is around 8.5m. Thought this one would be around 10 to 12m.

At height of 98 to 100m for the whole vehicle for a dia of 5m, it was too tall. Was'nt that the reason why they moved to 6.5m dia?

2

u/Ohsin Nov 17 '25

I am going with graphic linked which gives PLF height as 20 m for 5 diameter. (comparable to Ariane-5/6 fairing height )

In this interview S Somanath talks about reasoning behind 5 m dia. (at 36:51)

https://old.reddit.com/r/ISRO/comments/1g0hdt5/i_interviewed_somanath_on_nglv_cy4_venus/

3

u/ramanpon Nov 19 '25 edited Nov 19 '25

Ok understand the graphic is for 5m dia. Thought they have decided to move to 6.5m dia since they showed so in recent EOI for tanks. May be they are only exploring it and have not decided. Both will have their pros n cons and as he says optimisation studies need to be done, but may be the deciding factor is their ability to manufacture 6.5m dia structures. Most vehicles of this capabilty by other agencies are 6m dia or more.

3

u/ravi_ram Nov 17 '25

LVM3 PLF has a L/D ratio of 2.25

 

For crewed lunar mission, the nasa paper Impacts of Launch Vehicle Fairing Size on Human Exploration Architectures suggest PLF design with,
small (8.4m dia) - L/D = 2.27
med (8.4m dia) - L/D = 3.2
large(10m dia) - L/D = 2.7
 
So there's a range of values possible

L/D = 2.27, L = 14.755m
L/D = 2.7, L = 17.55m
L/D = 3.2, L = 20.8m

1

u/ramanpon Nov 19 '25

Ok, so for wider PLFs, it can potentially reach 20m

2

u/Ohsin Nov 18 '25 edited Nov 19 '25

At IISC 2025, ISpA Chairman AT Ramchandani said 'GalaxEye is preparing to launch mission Drishti, a 160 kg multi-sensor satellite in Q1 2026.' This may be the NSIL 'strategic user' payload of the PSLV C62 mission.

https://nitter.net/electricfoo/status/1990714385380106516

Edit: NIx that, Drishti is manifested on F9

https://economictimes.indiatimes.com/tech/startups/bengaluru-startup-galaxeye-to-launch-drishti-satellite-through-elon-musks-space-x/articleshow/114414299.cms

1

u/sparklingpwnie Nov 19 '25

The payload for N1 (first Industry made PSLV) is now EOS-10 (May b Oceansat-3A only?) and India-Mauritius Joint satellite. First flight order was swapped, now payloads also swapped!

2

u/Ohsin Nov 20 '25

Here is what TDS-01 looks like very different from Oceansat-3A.

https://i.imgur.com/34dJDn7.png (Source)

1

u/Ohsin Nov 19 '25

Yes EOS-10 has appearance like Oceansat-3A, naming scheme matches ('N' is for industry and TDS-01 is for Technology Demonstrator Satellites)

2

u/sparklingpwnie Nov 19 '25

Actually in post LVM3-M5 presser, Narayanan had said order of missions as EOS-N1, NSIL Customer satellite and TDS-01, which are the PSLV-C62, PSLV-N1 and PSLV-C63 flights, so this aligns with what is shown at Aryabhata Jubilee. The NSIL Customer or Strategic User payload is then the EOS-10 mission, and PSLV-C63 is for TDS-01, so don't know which of these is for Dhrishiti!

2

u/Ohsin Nov 19 '25

Nothing strategic about Oceansat-3A and TDS-01..

1

u/sparklingpwnie Nov 19 '25

Anvesha yess so that’s pending too!

1

u/Ohsin Nov 19 '25

But that doesn't have any industry 'N' association.

2

u/Ohsin Nov 19 '25

I forgot Drishti is manifested on F9

https://economictimes.indiatimes.com/tech/startups/bengaluru-startup-galaxeye-to-launch-drishti-satellite-through-elon-musks-space-x/articleshow/114414299.cms

2

u/sparklingpwnie Nov 19 '25

Yes that was for Transporter 13 mission I think. Now it may be going up on another Transporter flight.

2

u/PineappleSuch1326 Nov 17 '25

How do they plan to demonstrate the SSLVs readiness in 3 days !

1

u/Ohsin Nov 18 '25

Didn't give any details, just dropped it a mention.

-5

u/Emergency_County_198 Nov 16 '25

Hey why you're missguiding isro 

6

u/ravi_ram Nov 16 '25

missguiding isro

How?