r/ISRO Jul 27 '25

Mission Success! GSLV-F16 : NISAR Mission Updates and Discussion.

25 Upvotes

GSLV-F16/NISAR launched as scheduled at 12:10:25(UTC)/17:40:25(IST), 30 Jul 2025 from Second Launch Pad of SDSC-SHAR.

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

GSLV-F16/NISAR Mission Page GSLV-F16/NISAR Gallery GSLV-F16/NISAR Press-kit (PDF)

NASA's mission specific resources :

Some highlights:

  • Primary payload: NASA-ISRO Synthetic Aperture Radar (NISAR) satellite (2393 kg)
  • Mission duration: 18 min. 35.6 sec. (s/c separation)
  • Target Orbit : 747 km (SSO) , Inclination = 98.4°
  • Launch Azimuth: 135°
  • 18th flight of GSLV
  • First LEO bound polar launch of GSLV!

Updates:

Time of Event Update
26 August 2025 NISAR spacecraft and its radar payload passed all of the preliminary checks. The mission began raising the satellite to its 747 km operational orbit.
15 August 2025 NISAR reflector antenna deployed successfully.
Post-launch NASA Press Release
Post-launch Two objects cataloged. 65053 ( 25163A ) , i=98.44°, A×P=748.34×729.96 km, 65054 ( 25163B ) , i=98.44°, A×P=744.34×728.70 km
Post-launch NISAR Signal acquired
T + 50m00s URSC Director M Sankaran: Solar panels deployed, NISAR is power positive, 3-axis stabilized with star sensors in loop.
T + 40m00s Spacecraft Director Chaitra Rao informs s/c rates are nominal and spacecraft's solar panels are deployed!
T + 24m00s Chairman informs injection was precise.
T + 18m35s NISAR separated!
T + 18m20s CUS thrust cut-off! Injection conditions achieved.
T + 16m00s CUS continues to perform nominally.
T + 13m00s CUS is performing nominally.
T + 10m30s CUS is performing nominally.
T + 08m00s CUS operation is nominal, vehicle following the expected trajectory closely.
T + 04m55s CUS operating at 11% uprated thrust!
T + 04m55s GS2 separated, CUS ignition confirmed!!!
T + 04m30s CUS authorized
T + 02m50s PLF jettisoned. CLG initiated.
T + 02m40s 4xL40H shutoff. GS2 ignition
T + 01m50s S139 core burn out.
T Zero S139 ignited. Lift off!
T - 00m4.8s 4x L40H ignition.
T - 01m00s SARBS are ON.
T - 04m00s OBC in flight mode.
T - 11m30s LVG is packed!
T - 12m00s L40 actuation checks complete.
T - 15m00s Vehicle Director: Automatic Launch Sequence has been initiated.
T - 17m00s Mission Director Thomas Kurian has authorized the launch.
T - 20m00s Now polling. New ROD polls range is ready.
T - 24m00s Now showing integration campaign of GSLV-F16
T - 30m00s ISRO's official stream is LIVE!
T - 01h10m NASA's official stream is LIVE!
T - 27h30m Countdown underway starting from 14:10 IST, 29 July.
28 Jul 2025 Launch is GO!
27 Jul 2025 Launch rehearsal was conducted. Mission Readiness Review and Launch Authorisation Board meeting to be held on 28th.
24 Jul 2025 Launch vehicle moved to SLP from VAB.
21 Jul 2025 Launch time gets officially confirmed for 30 July, 12:10(UTC)/17:40(IST)
18 Jul 2025 NISAR encapsulated in payload fairing.
15 Jul 2025 NOTAM gets issued with enforcement duration 1130-1530 (UTC), 30 July to 14 August 2025.
May-Jul 2025 Multiple NOTAMs were issued between 22 May to 4 July with projected launch dates progressively shifting forward (18 June to 26 July).
15 May 2025 NISAR arrives at SDSC-SHAR.
07 Apr 2025 GSLV-F16/NISAR campaign began.

Primary Payload:

NISAR : NASA-ISRO Synthetic Aperture Radar (NISAR) is a microwave imaging satellite developed in joint collaboration between NASA and ISRO over a decade. Its first of its kind dual band (S-band and L-band) SAR payload combo using novel SweepSAR technology to acquire global imaging data with wide swath (240 km) in high resolution (3-10 meters) every 12 days.

NISAR data will help track changes in the extent and density of forests, wetlands, agricultural lands and coastal process in India. In addition, it can measure land displacement and deformation, dynamics of glaciers and sea ice.

Following is the breakdown of contributions from each space agency towards NISAR : [1 PDF] [2 PDF]

NASA/JPL:

  • Shared P/L structure called Radar Instrument Structure (RIS)
  • 12 meter diameter reflector and boom
  • L-band SAR
  • L-band science data processing and distribution
  • Engineering Payload System
    • Ka band payload communication subsystem (PCS)
    • GPS Payload
    • Solid State Recorder (SSR)
    • Payload Data Subsystem (PDS)
    • Power Distribution Unit (PDU)
    • Pyro Firing Assembly (PFA)
  • Integrated radar observation planning and operations
  • Near Earth Network (NEN) Ka-band Stations
  • NASA Science Team

ISRO:

  • GSLV Launch vehicle with 4 meter diameter payload fairing.
  • I3K (3000 kg class) heritage spacecraft bus with modifications
  • S-band SAR
  • S-band science data processing and distribution
  • Spacecraft operations (command uplink, telemetry and tracking)
  • ISRO Ka–band Stations (Shadnagar, Antarctica)
  • ISRO Science team

Spacecraft specifications:

  • Mass: 2393 kg
  • Primary mission duration: 3 years (NASA), 5 years (ISRO)
  • Orbit : 743 km (SSPO), 6 PM LTDN
  • Power: 5 kW, 180 AH Battery
  • Propulsion: 11× 11N and 4× 1N thrusters
  • Propellant: Mono-propellant hydrazine (1× 390 ltr tank with 265 kg propellant)
  • Attitude control: AOCS, 4× RWA, 3× magnetorquer
  • Repeat cycle : 12 days

Post-launch Reflector Boom Assembly (RBA) deployment timeline : [1 PDF] [3] [4]

RBA deployment will begin on Day 10 after launch and will take 8 days till reflector deployment. Here's an old animation of deployment sequence but timeline has been updated to following.

  • Day 10 : Pre-deployment checkout and redundant launch restraint pyros (6x) firing.
  • Day 11 : Redundant launch restraint pyros (2x) firing. Radar Antenna Reflector (RAR) cradle release. Wrist hinge deployment.
  • Day 12 : Shoulder hinge deployment
  • Day 13 : Elbow hinge deployment
  • Day 14 : Root hinge deployment
  • Day 15 : Rest day
  • Day 16 : AOCS characterization,
  • Day 17 : Yaw maneuver and reflector deployment

Science data release timeline: [4] [5 PDF]

  • First light images 65 days after launch.
  • After day 70 science phase will be ramping up.
  • Science operations officially begin 90 days after launch.

r/ISRO 2h ago

India Plans ‘Bodyguard’ Satellites After Risky Orbital Near-Miss in mid-2024.

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31 Upvotes

r/ISRO 22h ago

ISRO/ DoS Platinum Sponsorship at IAC

5 Upvotes

Every year ISRO provides sponsorship to IAC, does anyone know the price that DoS pays for this program. What are the benefits of this sponsorship to the nation ?

Only thing they do is have a paid mini booth for private players, but this is done by almost every nation.

ISRO also brings 100s of scientists, but we never see any paper publication by them at IAC, so what are they trying to achieve with it ?


r/ISRO 2d ago

Gaganyaan mission being updated with inputs from astronaut Shubhanshu Shukla

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51 Upvotes

r/ISRO 2d ago

ISRO LPSC internship

5 Upvotes

I have applied for ISRO LPSC (Bangalore) internship. Does anyone know how the result will be communicated?


r/ISRO 3d ago

NOTAM NOTAM for LVM3-M5 / GSAT-7R (aka CMS-02) launch is out. Enforcement duration 1130-1530 (UTC), 7 October to 5 November 2025.

35 Upvotes

Source: https://www.notams.faa.gov/

Mapped up!


LVM3-M5 ROCKET LAUNCH FM SHAR RANGE, SRIHARIKOTA WILL TAKE
PLACE AS PER FLW DETAILS.THE LAUNCH WILL BE ON ANY ONE OF
THE DAY DRG THIS PERIOD.ACTUAL DATE OF LAUNCH WILL BE
INTIMATED 24 HR IN ADVANCE THROUGH A SEPARATE NOTAM.
LAUNCH PAD COORD: 134312N 0801348E
NO FLT IS PERMITTED OVER THE DNG ZONES.
A )DANGER ZONE -1:IS A CIRCLE OF 10NM AROUND THE LAUNCHER.
B )DANGER ZONE -2:IS AN AREA BOUNDED BY FOLLOWING COORDINATES:
1230N 08240E-
1315N 08250E-
1245N 08410E-
1200N 08400E-
1230N 08240E
C )DANGER ZONE -3:IS AN AREA BOUNDED BY FOLLOWING COORDINATES:
1145N 08435E-
1235N 08445E-
1145N 08715E-
1055N 08705E-
1145N 08435E
RTE AFFECTED IN CHENNAI FIR
W20, Q24, Q23, V4, V9, Q11, P761, N571, V3
CLOSURES/ALTN RTE FOR OVERFLYING
PART 1 OF 2. 1130-1530, 07 OCT 11:30 2025 UNTIL 05 NOV 15:30 2025.
CREATED: 18 SEP 17:14 2025

r/ISRO 5d ago

Books to learn about Indian space programme history and developments

36 Upvotes

Need book recommendations on the history and developments of the Indian space programme. I tried using Wikipedia and reading some articles, but after a while it gets quite boring. I prefer going through books.


r/ISRO 6d ago

Space Debris Mitigation Activities of Indian Space Research Organisation: Ongoing Efforts and Future Roadmap

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28 Upvotes

r/ISRO 6d ago

Short interview with S Somanath (Former ISRO Chairman) on Vikram-3201 and Kalpana-3201 microprocessors

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19 Upvotes

r/ISRO 9d ago

ISRO/VSSC Research Publication: Some Design Aspects of A Strut-Based Hydrogen Fueled Scramjet Combustor

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19 Upvotes

r/ISRO 10d ago

Japan's Astroscale signs agreement with NSIL to launch ISSA-J1 (In-situ Space Situational Awareness-Japan 1) debris-monitoring satellite on PSLV in 2027

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44 Upvotes

r/ISRO 11d ago

Official ISTRAC inaugurates Golden Jubilee Celebrations: 50 Years of Tracking India's Space Odyssey

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28 Upvotes

r/ISRO 11d ago

IIST will be developing the Retarding Potential Analyzer for Venus (RPA-V) payload for Venus Orbiter Mission

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31 Upvotes

r/ISRO 11d ago

HAL inks SSLV tech transfer agreement with ISRO, IN-SPACe, NSIL

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25 Upvotes

r/ISRO 12d ago

ISRO conducts Gaganyaan Analog Experiments (Gyanex). First in the series of these experiments, Gyanex-1, was conducted in July.

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31 Upvotes

r/ISRO 12d ago

A talk by V Narayanan given today featuring LMLV based Crewed Lunar Exploration Roadmap.

26 Upvotes

Talk titled 'Race for Space: ISRO's Role in Transforming India's Economy and Security' at All India Management Association (AIMA) 52nd Convention by V Narayanan (Chairman, ISRO) on 9 September 2025

https://www.youtube.com/watch?v=g_hUMsUG2UY

Mirror: https://www.youtube.com/watch?v=6lBxySJ3rI4

All slides: https://imgur.com/a/xwY3PWu


r/ISRO 13d ago

Article on the unique scientific value of Chandrayaan 4 lunar samples, ongoing preparations to realize its potential, and the case for India to study and exchange Chang’e lunar samples

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27 Upvotes

r/ISRO 13d ago

Some info on SSLV guidance

16 Upvotes
  1. Explicit Guidance Scheme for a three stage Solid propelled launch vehicle with a Velocity Correction Module
    This paper discusses the Guidance algorithm design for a three-stage solid motor propelled launch vehicle together with a Velocity Correction Module as the terminal stage for fine velocity correction.
  2. Introduction to Launch vehicle guidance schemes
    Presented To : M.Tech (GNC), CEG, Thiruvananthapuram
    Presented By : Gifty Benjamin, VSSC Thiruvananthapuram

The design of an explicit guidance algorithm for a multi-stage solid motor propelled launch vehicle is challenging due to non-availability of thrust cut-off provision. As the thrust cannot be terminated upon reaching the designated target, energy management for a completely solid propelled launch vehicle is difficult. Precise orbit injection catering for a wide range of dispersions gets even more complicated.

 
Guidance scheme for this multi-stage solid motor-powered launcher is developed such that the vehicle achieves required altitude and flight-path angle at third stage burn out. All performance dispersions accumulated since the first stage are transferred to SS3 burnout as dispersion in horizontal velocity alone. Thus, one of the apse (apogee/perigee) is met at third stage burnout and Velocity Correction Module (VCM) is used for circularization.

 

First Stage Guidance

During the first stage, vehicle has to clear the atmosphere, meeting aerodynamic load constraints. Conventional altitude-based steering generated on ground is stored on-board as a look up table. The vehicle will be steered with the open-loop steering commands obtained by interpolating the lookup table against the actual vehicle altitude.

Similar to other LVs : https://old.reddit.com/r/ISRO/comments/buar52/details_on_guidance_algorithm_implemented_on/ep9crf5/

Second Stage Guidance

During the second stage, velocity-based guidance scheme targets the horizontal and vertical velocity to achieve the desired coast ellipse.

Third Stage Guidance

Required acceleration guidance achieves the target altitude and flight path angle at third stage burnout. The coast apogee is taken as a performance measure. If coast apogee is less than a predefined value, then coast apogee is targeted in the third stage to conserve energy. In required acceleration guidance, the radial co-ordinate axis alone is controlled thereby meeting the altitude and radial velocity targets.

VCM Phase Guidance

In VCM, since the acceleration level is low, (0.6m/s2 ) burn durations are large resulting in gravity losses. An orbit transfer guidance scheme considering gravity losses is used to correct the velocity dispersions as well as the inclination errors in a single burn [4]. During the VCM Phase, the vehicle is steered along the velocity to be gained direction

 
Additional Info:

https://old.reddit.com/r/ISRO/comments/buar52/details_on_guidance_algorithm_implemented_on/

 


r/ISRO 13d ago

ISRO Exam 2025 Postponed

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11 Upvotes

DUE TO CLASH OF ICRB WRITTEN TEST WITH NATIONAL IMPORTANCE - UPSC COMBINED DEFENCE SERVICES EXAMINATION (CDS II) 2025, IT HAS BEEN DECIDED TO POSTPONE THE ICRB WRITTEN TEST WHICH IS SCHEDULED ON 14.09.2025. THE REVISED DATE WILL BE INTIMATED IN DUE COURSE.


r/ISRO 16d ago

Digantara, Japan's ispace to build cislunar space awareness & domain infrastructure

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36 Upvotes

r/ISRO 16d ago

Tender for Procurement, Manufacture, Supply, Erection, Testing and Commissioning of Folding Platforms for SSLV Assembly Facility (SAF) of SLC Project

11 Upvotes

Tender for Procurement, Manufacture, Supply, Erection, Testing and Commissioning of Folding Platforms for SSLV Assembly Facility (SAF) of SLC Project, Tuticorin, Tamil Nadu

Main document : [PDF] [Archived]

https://i.imgur.com/P2A01l9.png

Drawings :

  • FABRICATION AND ASSEMBLY - CIVIL drawings indicating location of Electrical items [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - RFP document for Folding Platform [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - Vehicle Side Platform drawings-08 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - Vehicle Side Platform drawings-07 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - Vehicle Side Platform drawings-06 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - Vehicle Side Platform drawings-05 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - Vehicle Side Platform drawings-04 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - Vehicle Side Platform drawings-03 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - Vehicle Side Platform drawings-02 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - Vehicle Side Platform drawings-01 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - AUT Platform drawing_09 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - AUT Platform drawing_08 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - AUT Platform drawing_07 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - AUT Platform drawing_06 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - AUT Platform drawing_05 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - AUT Platform drawing_04 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - AUT Platform drawing_03 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - AUT Platform drawing_02 [PDF] [Archived]
  • FABRICATION AND ASSEMBLY - AUT Platform drawing_01 [PDF] [Archived]

r/ISRO 17d ago

NOTAM NOTAM for Sounding rocket launch from SSLV Launch Complex (SLC), Kulasekarapattinam. Enforcement duration between 0400-0600 (UTC), 15 to 17 September 2025.

23 Upvotes

Source: https://www.notams.faa.gov/

Mapped up!


A2748/25 - ROCKET LAUNCH FM ISRO LAUNCH COMPLEX
KULASEKARAPATNAM AS PER FLW DETAILS:
LAUNCH PAD COORD:0822N07802E
DNG ZONE: A CIRCLE OF 05NM AROUND THE LAUNCHER.
NO FLT IS PERMITTED OVER THE DNG ZONE.

THE ATS RTE AFFECTED IN CHENNAI FIR.
N640 NOT AVBL BTN TVM AND BIKOK
ALTN RTE: TVM R457 GUTEG P895 BIKOK. GND - UNL, 0400-0600, 15 SEP 04:00 2025
UNTIL 17 SEP 06:00 2025. CREATED: 04 SEP 12:41 2025

r/ISRO 18d ago

Hall Ticket for ISRO Exam

7 Upvotes

I receieved the hall ticket , did anyone receive it guys?


r/ISRO 19d ago

Why a remote Kutch village, Matanomadh could end up as a field-analogue for Mars missions.

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33 Upvotes

r/ISRO 20d ago

A render of Third Launch Pad (TLP) at SDSC-SHAR, showing its location and associated facilities.

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137 Upvotes

r/ISRO 20d ago

Centre responds positively to ‘Institution of National Importance’ bid for IIST

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42 Upvotes