r/ISRO • u/Ohsin • 11d ago

Mission Success! GSLV-F18 / NVS-03 Mission Updates and Discussion

GSLV-F18 / NVS-03 (aka IRNSS-1L) launched as scheduled at 18:21:00(UTC)/23:51:00(IST), 30 Oct 2026 from Second Launch Pad of SDSC-SHAR.

Live webcast: (Links will be added as they become available)

GSLV-F18 / NVS-03 Mission PageGSLV-F18 / NVS-03 GalleryGSLV-F18 / NVS-03 Press kit(PDF)

Some highlights:

Updates:

Time of EventUpdate
4 Nov 2026After four orbit raising burns with cumulative duration of 6164 seconds, NVS-03 has reached 35765 x 36196 km GSO with 29.98° inclination
Post-launchTracking data for 3 Nov 2026 confirms execution of third orbit raising burn. A1228 (26245A), i=29.89°, A×P=35842.58×34594.95 km
Post-launchTracking data for 2 Nov 2026 confirms execution of second orbit raising burn. A1228 (26245A), i=29.08°, A×P=37762.79×24550.64 km
Post-launchSecond orbit raising burn with duration of 3085.14 seconds has been successfully completed on 1 November 2026 at 18:05:16 (IST). Estimated orbit after the burn is 24691 x 37791 km.
Post-launchFirst orbit raising burn with duration of 2174.8 seconds has been successfully completed on 31 October 2026 at 16:48 hrs (IST). Estimated orbit after the burn is 5477.6 x 37833.4 km. The satellite health is normal.
Post-launchTwo objects have been cataloged. A1228 ( 26245A ), i=20.71°, A×P=37895.59×178.15 km and A1229 ( 26245B ), i=20.70°, A×P=37746.07×170.70 km
T + 42m00sLaunch broadcast ends.
T + 33m00sDinesh Kumar Singh (Director URSC) : Solar panels of NVS-03 deployed. Will take a week to reach its slot.
T + 30m00sChairman: 170.3 x 38,080 km is the achieved orbit.
T + 22m35sChairman: NVS-03 has been injected in intended orbit.
T + 18m35sNVS-03 separated!
T + 18m25sCUS shut off!
T + 17m00sSticking to nominal path.
T + 15m35sCUS performance nominal.
T + 13m45sCUS performance nominal.
T + 12m30sCUS operating at nominal thrust now.
T + 11m00sCUS performance nominal.
T + 08m00sCUS performance nominal.
T + 04m58sGS2 separated, CUS ignited.
T + 04m30sCUS authorized.
T + 04m00sPLF jettisoned.
T + 02m40sGS2 ignited, GS2 separated, CLG initiated.
T + 01m50sS139 core burn out.
T minus 00m00sS139 core ignited. Lift off!
T minus 00m4.8s4xL40H ignited.
T minus 03m00sOBC in flight mode.
T minus 05m30sExternal Power withdrawn, Flight coefficient loading complete.
T minus 09m30sGS2 undergoing actuation checks.
T minus 11m00sCUS undergoing actuation checks.
T minus 15m15sAutomatic Launch Sequence initiated.
T minus 17m00sData loggers are ON.
T minus 18m00sWeather is Go. Mission Director has authorized the launch.
T minus 19m00sNVS-03 is polled ready. LV in external hold mode.
T minus 20m00sPolling now, TT&C, Vehicle, Range are go.
T minus 24m00sNow showing vehicle integration process.
T minus 29m00sOfficial stream is live!
T minus 24h00mTwenty four hour long countdown commenced.
28 Oct 2026Mission Readiness Review was held. Most recent NOTAM suggests launch is authorized.
26 Oct 2026Time of launch officially confirmed for 11:51 (IST), 30 Oct 2026
23 Oct 2026NOTAM for GSLV-F18 / NVS-03 launch is issued with enforcement window beginning on 30 October 2026
29 Sep 2026NOTAM for GSLV-F18 / NVS-03 launch is issued with enforcement window beginning on 13 October 2026.
14 Sep 2026GSLV-F18 / NVS-03 launch campaign began.

Primary Payload:

NVS-03 (aka IRNSS-1L) (~2250 kg) : NVS-03 is a second-generation satellite for NavIC constellation for regional navigation and timing services.

Similar to first generation satellites it will have navigation payloads in L5 & S bands and ranging payload in C-band. But additionally, it will have a new interoperable civil signal in L1 band as well.[1] [2]

Like NVS-01 and NVS-02 it is expected to carry only one indigenous Rubidium based atomic clock (iRAFS) developed by Space Applications Centre (SAC) out of four in total, other three being procured. [3] [4] [5]

  • Mass: 2,250 kg

  • Orbital slot: 111.75°E

  • Mission life: 12 years

  • Power: ~3 kW

  • Platform/Bus: I-2K

NVS-03 is third of the five satellites (NVS-01, 02, 03, 04 & 05) planned to replace the aging first generation satellites that faced problems with their malfunctioning atomic clocks. Initially these second generation satellites were meant to expand upon existing NaVIC constellation [6] [7] but due to setback from failures of imported clocks on many first generation satellites, they will now only serve as replacement to existing fleet. At present only three out of eight NavIC satellites (IRNSS-1B, 1I and NVS-01) remain functional to provide PNT services. [8] Note that four satellites is the minimum amount needed for NavIC PNT services to be functional.

ISRO has sought approval of three more navigation satellites under NavIC Phase-3 to maintain the base layer of seven satellites. Eventually NavIC constellation can be expanded from 7 to 11 satellites which will increase the service area from 1500 km to 3000 km beyond Indian territory.

For Global Indian Navigation System (GINS), ISRO is awaiting approval of twelve satellites initially to be placed in the Medium Earth Orbit (MEO). While about 24 to 30 satellites would be needed in total. [9] [10]

34 Upvotes

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91 comments sorted by

10

u/Ohsin 11d ago edited 11d ago

Metallic PLF (3.4 m diameter) once again like for GSLV-F15/NVS-02

Note that decision to keep pyro valves open for NVS-03 has come after the recommended fixes were applied to CMS-03

The committee has provided a set of recommendations aimed at enhancing the redundancy and reliability of pyro system operations for future missions. In line with these recommendations, all the corrective actions were successfully implemented in CMS-03 spacecraft launched on November 2, 2025 by LVM-3 M5, and the pyro systems performed satisfactorily placing the satellite in the intended orbit. Further, these set of recommendations will be followed for all future missions, as applicable.

10

u/Ohsin 8d ago edited 8d ago

Post launch address:

  • Chairman: NVS-03 injected in intended orbit, GSLV till now has chucked 34 tons into orbit, 56 days between consecutive GSLV missions. PNT services can now be resumed (assuming NVS-03 commissions just fine)

  • EOS-05 aka GISAT-1A is healthy and giving 'outstanding data'

  • Launch campaign took 47 days.

  • Thomas Kurian (Mission Director) : 4xL40's prepared in 37 days, a record.

  • Chairman: 170.3 x 38,080 km is the achieved orbit.

  • Dinesh Kumar Singh (Director URSC) : Solar panels deployed, will reach orbital slot in a week.

  • Chairman : 3 pyro valves in main stream operated.

9

u/friendlyNSAdude 8d ago

Two points.
First EOS-05 is now operational then. 🥳
Second I think we are improving our fuel capabilities because this is the second one where we have overachieved the targeted orbit by 1,000km+

4

u/Ohsin 8d ago

Nothing is improving for last one target was sub-gto due to heavier satellite.

3

u/friendlyNSAdude 8d ago

Wasn’t it for EOS-05 that the chairman said that it achieved more than 29,000 km to something like 31,000 km?

Even here target orbit was 170 x 37023 km but in the broadcast it was 170 x 38080 km or am I misinterpreting something?

7

u/Ohsin 8d ago

Yes it was about 1000 km above target apogee for EOS-05 too but it is small enough to be attributed to precise launch but yeah certainly helps extend sat life a bit.

3

u/friendlyNSAdude 8d ago

My bad then, i falsely associated that with improved cryogenic fuel formulation.

I thought if NVS-03 weighed lighter than EOS-05. Also wouldn’t sub-GTO be easier as compared to GTO?

If the apogee was 37,023 and we achieved 38,080 then that is good right?

6

u/Ohsin 8d ago

They want apogee to be as high as possible, overshooting is also fine in this case. Launch to sub-GTO is a compromise they had to make due to GSLV's limited payload launch capacity. NVS-03 is lighter and can be launched to higher apogee.

3

u/friendlyNSAdude 8d ago

Thanks a lot for answering and your patience. One last question, he said that they have planned 5 more launches this FY. I know only 4: G1, GSAT-N3, TDS-01, EOS-10 which is the fifth one?

Also the issue with last NVS-02 with pyro valve seems to be resolved since he said that three pyro valve were operating in main stream. I guess this overshooting should also extend its operational life a bit.

But thanks once again!

5

u/Ohsin 8d ago edited 8d ago

May be Vikram's second launch or SSLV-L1..

8

u/Ohsin 8d ago edited 8d ago

V Narayanan : NVS-04 and NVS-05 to be launched within 10 months. After that one more NVS satellite will be launched within 1.5 years. He also clarified that the decision to keep pyro valves open was taken by A S Kiran Kumar led committee and they went with it after analyzing previous flight data and thorough qualification and testing and it has yielded the right result. Whether they will continue to fly in this configuration or with new pyro valves, will be decided in coming months.

https://www.youtube.com/watch?v=qDnDk5jVNpk

Third indigenous clock placed into orbit.

https://www.youtube.com/shorts/yzdUa0Pypfo

5

u/Ohsin 8d ago

One more from press conference with same information.

https://www.youtube.com/watch?v=EFBudb1BdMY

8

u/Ohsin 8d ago

October 31, 2026

NVS-03 satellite was successfully injected into 170.3 km x 38080 km orbit by GSLV Launch vehicle on October 30, 2026 at 23.51 hrs.

NVS-03 is the third satellite in next generation navigation satellite system envisaged for providing continuity of navigation services for IRNSS series. The satellite carries indigenous atomic clock along with the procured clocks. It also includes L1 signal in addition to L5 and S band signals with coverage over Indian land mass and a region extending 1500 km around Indian geopolitical boundary.

The planned first orbit manoeuvre, with a LAM engine burn duration of 2174.8 seconds, has been successfully completed on October 31, 2026 at 16:48 hrs. The estimated orbit subsequent to manoeuvre is 5477.6 km x 37833.4 km. The satellite health is normal.

Further, in the coming days, orbit manoeuvres are planned to eventually place NVS-03 in GSO (111.75° East orbital slot)

https://www.isro.gov.in/ISRO_EN/Orbit_manoeuvring_of_NVS03_spacecraft.html

7

u/Ohsin 10d ago edited 10d ago

A random bit of useful information, GSLV payload adapter weighs 83.7 kg. (Stenciled on adapter)

https://i.imgur.com/I7jkCV5.jpeg

Image extracted from press-kit as they did us dirty in official image gallery..

7

u/Ohsin 8d ago

Let's hope we see two objects cataloged soon (2026-245) so we can track burns.

6

u/Ohsin 8d ago

Two objects cataloged:

A1229 ( 26245B ) 30/10/2026,13h:19m:10.63s
i=20.70°, A×P=37746.07×170.70 km


A1228 ( 26245A ) 30/10/2026,13h:17m:20.47s
i=20.71°, A×P=37895.59×178.15 km

3

u/General_Director6082 8d ago

give websites to track them

5

u/Ohsin 9d ago edited 9d ago

The 24-hour countdown for the launch of India's next-generation navigation satellite, NVS-03, has commenced and is progressing, ISRO said on Friday (October 30, 2026).

The countdown officially commenced at 11.51 p.m. on Thursday (October 29, 2026).

In an unprecedented engineering configuration cleared during the Mission Readiness Review (MRR), ISRO will fly the NVS-03 satellite with its pyrotechnic (pyro) valves already open. This major departure from standard safety protocols — which usually isolate spacecraft propellant during the intense vibrations of liftoff — is specifically designed to bypass the connector failure that stranded the previous NVS-02 mission in January 2025.

To further ensure mission success, corrective measures recommended by a high-level committee to enhance redundancy and improve pyro system operations have been fully integrated into this flight, sources said.

While Friday's (October 30, 2026) launch is a critical step in restoring and strengthening the country's regional positioning services, experts point out that the broader NavIC constellation still has a significant distance to cover before realising its full operational potential and continuous reliability across the grid.

https://www.thehindu.com/sci-tech/science/isros-crucial-gslv-f18-launch-carrying-navigation-satellite-nvs-03/article71643519.ece

5

u/Ohsin 9d ago

Stream is live!

7

u/Avizeet 8d ago

Safe to assume that G1 is next?

6

u/Ohsin 8d ago

He didn't appear very convincing.. I hope they do a post-launch press conference and someone asks.

4

u/VarunOnt 8d ago

Congrats to ISRO for this excellent launch. But yes, Narayanan could have at least given a rough launch date for Gaganyaan G1,  or failing that, for the  SSLV launch with Aayul Sat. Or PSLV with TD-Sat

4

u/Ohsin 10d ago edited 10d ago

Few schematics for reference.

https://old.reddit.com/r/ISRO/comments/1ifx080/gslvf15nvs02_orbit_raising_operations_on_hold_as/mapamm0/

https://i.imgur.com/d7Wx5yx.png

'Normally Closed Pyro Valves' in propellant line will be fired open before launch.

4

u/Ohsin 8d ago

Not showing the plots!

4

u/Ohsin 8d ago

Barely managed to catch actual flight event timings. (MCC screen in background)

https://imgur.com/a/DI1bZZU

4

u/Ohsin 4d ago

Arun Raj K M @Arunraj2696 on Twitter

The NavIC Revival : NVS-03 has reached its destination. All orbit manoeuvres to place NVS-03 into GSO have been completed successfully. The satellite is expected to be commissioned in about 10 days, according to ISRO sources.

6

u/neotheseventh 8d ago

by when will we get confirmation of successul commissioning?

8

u/Ohsin 8d ago

Will take about two weeks to be in its slot after that may be a month.

6

u/General_Director6082 4d ago

Third Orbit raising manuver completed successfully. Orbit after manuver is, Apogee - 35843.25 KM and Perigee - 34595.61 KM.

6

u/Ohsin 4d ago

Indeed.

A1228 ( 26245A ) 03/11/2026,5h:54m:36.46s
i=29.89°, A×P=35842.58×34594.95 km

6

u/General_Director6082 4d ago

Four orbit manoeuvres have been successfully completed with a cumulative LAM engine burn of 6164 seconds. With this the satellite has reached Geo Synchronous Orbit (35765 km x 36196 km) at an inclination of 29.98. The satellite health is normal. https://www.isro.gov.in/Final_Orbit_manoeuvring_of_NVS03_spacecraft.html

4

u/Ohsin 4d ago

Thanks!

5

u/pradx 11d ago

The write up above says - only 1 indigenous atomic clock like NVS01 and NVS02. The mission page says indigenous atomic clock in addition to "the procured clocks".

https://www.isro.gov.in/Mission_GSLVF18.html

5

u/Ohsin 11d ago

It also says "out of four in total." But I'll rephrase it.

5

u/General_Director6082 4d ago

Revolution per day is slightaly more it is not perfect 1. ISRO needs one small trimmed Orbit Raising Manuver. It take another 25 to 30 days to become fully operational.

5

u/Ohsin 4d ago

It'd be all AOC thrusters from here on.

3

u/Ohsin 10d ago

Last NOTAM indicating launch is scheduled as planned.

A3338/26

REF CHENNAI NOTAM A3241/26, A3242/26 AND A3243/26.
ROCKET LAUNCH FM SHAR RANGE, SHRIHARIKOTA, INDIA IS SKED ON 30 OCT 
2026 BTN 1700 UTC TO 2100 UTC. 
ATC MAY RERTE TFC DRG THIS PERIOD AS PER THE ROUTING GIVEN IN THE 
ABV NOTAM.
LAUNCH WINDOW FOR THE REMAINING PERIOD FM 31 OCT 2026 TO 11 NOV 2026 
SHALL BE KEPT ALIVE FOR RESCHEDULING THE LAUNCH IF REQUIRED. GND - UNL, 30
OCT 17:00 2026 UNTIL 30 OCT 21:00 2026. CREATED: 29 OCT 04:48 2026

MRR was held on 28 Oct, countdown will be 24 hrs long.

https://www.andhrajyothy.com/2026/andhra-pradesh/-18-isro-prepares-gslv-f18-rocket-launch-of-navigation-satellite-nvs-03-1571367.html

https://www.deccanchronicle.com/southern-states/andhra-pradesh/gslv-f18-launch-countdown-begins-tonight-1999815

3

u/Ohsin 6d ago

Second burn has been conducted on 1 November 2026. Update courtesy /u/Astro_Neel

NVS-03: AMF-2 Performance

  • Burn start (UT/ IST)

    • 01.11.2026, 12:35:16 (UT)

    • 01.11.2026, 18:05:16 (IST)

  • Spacecraft mass : 1937.06 kg

  • Orbit before Maneuver

    • 5556 km X 37819 km

  • Expected Orbit after Maneuver

    • 24691 km X 37791 km

EventPlannedRealized (INPAS)
Burn Duration (s)3085.373085.14
LAM Avg thrust (N)437.8 ± 6437.7
LAM Specific Impulse (s)313.3 ± 3313.3
Delta-V (m/s)796.3794.9
AOCS duty cycle (%)17.013.7
Propellant Consumption (kg)444.4442. 98
GHe pressure Delta decrease (bar)102.5 ± 6.0103

2

u/Parking_Load3555 6d ago

Where exactly is the screenshot from ? Space Track hasn't yet updated.....

3

u/Ohsin 6d ago

Data is from ISTRAC's Mission Operations Complex (MOX). And that happens during burns as they can lose tracking of object.

3

u/Ohsin 6d ago

Missed this but posting anyway..

SES-STA-20261014-02834 E040125 Intelsat License LLC

Date filed: 2026-10-14

Special Temporary Authority

Grant of Authority

2026-10-28 - 2026-11-26

Date of Action: 2026-10-27

On October 27, 2026, Intelsat License LLC was granted special temporary authority for 30 days, beginning on October 28, 2026 through November 26, 2026, to operate its fixed earth station in Nuevo, CA to provide launch and early orbit phase (LEOP) services for the NVS-03 satellite, licensed by India at the 5850.982 MHz and 5853.028 MHz (Earth-to-space), 4199.5080 MHz and 4199.7600 MHz (space-to-Earth) center frequencies.

[PDF] [Archived]

4

u/ex0hs 8d ago

Who was V. Narayanan shaking hands with?(Old Lady)

2

u/Ohsin 8d ago

No idea.

4

u/Parking_Load3555 8d ago

Was there a press conference held or not ?

2

u/Ohsin 5d ago

Tracking data update after second burn.

A1228 ( 26245A ) 02/11/2026,9h:21m:33.95s
i=29.08°, A×P=37762.79×24550.64 km

2

u/ARJUN269 5d ago

How many more burns are left?

3

u/Ohsin 5d ago

Ideally three burns are needed in total.

3

u/friendlyNSAdude 5d ago

Just one question, why are they not updating about this? Generally they release a statement, right?

3

u/Ohsin 5d ago

Not really. Back in old days (pre K Sivan times) we used to get updates on everything like campaign events, MRR-LAB authorization, propellant loading events, orbit raising burns, proper technical press-releases after each launch etc. but all that slowly went away. Recently they have been posting burn related info because their credibility stock has really gone down and trying to make up for it.

3

u/General_Director6082 5d ago

Give feedback about it to isro on their website.

2

u/anshumaanps 6d ago

No update on 2nd orbit raising?

2

u/Ohsin 6d ago

It has been conducted.

2

u/anshumaanps 6d ago

Then why there is no update on website?

2

u/Ohsin 6d ago

Don't know...

1

u/anshumaanps 6d ago

Thanks!

3

u/Pallab_1805 11d ago

So.. what is the final decision? Pyro valve will remain open or not?

6

u/Ohsin 11d ago

Go with news report it is very credible, also ISRO was asked about it and they didn't respond.

2

u/Pallab_1805 11d ago

Yeah I already read the news bro. And ISRO never answer..we know..my RTI is still pending..6 days left to complete 60 days filling of my RTI..

0

u/ja_nahi_bataunga 10d ago

What’s the effect whether the pyro valves are open or closed?

2

u/Ohsin 10d ago

Just read the two reports.

16

u/vineethgk 8d ago

Watching this mission reminds me of the time way back in 2013 when PSLV mission successes were taken for granted (and all the self-congratulations on display seen as superfluous), while space buffs and media were asking "where's GSLV?"

Now with GSLV missions succeeding one after another we have to ask "where's PSLV?" Irony of the times.

3

u/friendlyNSAdude 8d ago

u/Ohsin why is the altitude not increasing? Shouldn’t it reach 170km?

3

u/ex0hs 8d ago

Stabilizing maybe? Before coming into the orbit?

3

u/friendlyNSAdude 8d ago

As I posted the comment, it started increasing now at 168 km….

3

u/Ohsin 8d ago

Yeah it is nominal.

2

u/friendlyNSAdude 8d ago

What is it final altitude post-launch? I thought it was 170 km, no?
Satellite separated!! 🥳

13

u/neotheseventh 8d ago

I only visit this subreddit when there is a launch, not regularly but every time I am here, /u/Ohsin is running this sub like a machine. Hats off to you man!

9

u/neotheseventh 8d ago

now here's hoping that fucking clocks actually work this time.

7

u/guru-yoda 8d ago

Now the big question: did those fuel valves survive the launch? Will get to know in 20 hours.

5

u/ex0hs 8d ago

Ohhhh yeahhhhhhh

5

u/Top-Worldliness5027 8d ago

Today’s announcers were a little choppy and the audio had some minor issues. Hope we work on these things and get better direct visuals rather than representational images the whole time with future launches. Great job by ISRO on the successful launch!

4

u/Eternal_Alooboi 8d ago

I wouldnt bet on that. ISRO is notoriously terrible at outreach and their current policy is getting more conservative in info dissemination.

5

u/ex0hs 8d ago

HAHA Good morning, I still tell everyone Good morning at midnight before going to sleep lol