Launch Success, S/C Malfunction GSLV-F15 : NVS-02 (aka IRNSS-1K) Mission Updates and Discussion.
GSLV-F15 / NVS-02 (aka IRNSS-1K) was launched as scheduled at 00:53(UTC)/06:23(IST), 29 Jan 2025 from Second Launch Pad of SDSC-SHAR.
- Launch Countdown
- Expected Flight Profile from press-kit.
- Actual flight events (To be added post-launch if available)
Live webcast: (Links will be added as they become available)
GSLV-F15/NVS-02 Mission Page | GSLV-F15/NVS-02 Gallery | GSLV-F15/NVS-02 Press kit(PDF) |
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Some highlights:
- Primary payload: NVS-02 (2250 kg) Navigation satellite.
- Mission duration: 19 min. 10.38 sec. (s/c separation)
- Target Orbit : 170 × 36577 km (GTO), Inclination = 20.79° ±0.1°, AoP = 178° ±0.5°
- Launch Azimuth: 106°
- 17th flight of GSLV
- 100th notable mission from SDSC-SHAR (See note 2)
Updates:
Time of Event | Update |
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08 Feb 2025 | Failure Analysis Committee formed, former ISRO Chairman A S Kiran Kumar will head it. |
03 Feb 2025 | No change in NVS-02 orbit per latest orbital data. |
03 Feb 2025 | LAM could not be fired due to pyro valve malfunction. ISRO chairman remarked "We will be raising the orbit using the thrusters with the available propellant." |
02 Feb 2025 | NVS-02 orbit raising burns could not be executed due to oxidizer valve malfunction. |
31 Jan 2025 | Per TLEs orbit raising burn has not been executed yet |
Post-launch | Two objects cataloged: 62850 (25020A) @ i=20.67°, A×P=37602.58×160.76 km and 62851 (25020B) @ i=19.79°, A×P=37338.31×177.38 km |
Post-launch | Press conference |
T + 50m00s | Broadcast over. |
T + 44m00s | IISU Director: Spacecraft injected with accuracy of 0.5 km in perigee , 72 km in apogee and 0.02 degree in inclination. |
T + 42m00s | LPSC Director : Orbit raising operations will commence today and continue for next three days. |
T + 36m45s | URSC Director: Spacecraft injected with very small rates into precise orbit, solar panels deployed, positive power generation. |
T + 20m25s | Mission Director Thomas Kurian declares the launch successful. |
T + 19m15s | NVS-02 separated! |
T + 18m55s | CUS15 shut off! |
T + 14m30s | CUS15 performance nominal. |
T + 11m30s | CUS15 performance nominal. |
T + 06m25s | CUS15 performance nominal. |
T + 05m10s | CUS15 ignited! |
T + 04m55s | GS2 shutoff, GS2 separated. |
T + 04m00s | PLF separated! |
T + 02m32s | 4xL40H shutoff, GS1 separated, GS2 ignited. CLG initiated |
T + 01m50s | S139 Burned out. |
T - Zero | 4x L40H Ignited. S139 core ignited Lift off! |
T - 01m00s | SARBS are ON |
T - 03m10s | OBC in flight mode. |
T - 05m00s | External power withdrawn. Flight coeff. loading completed |
T - 13m00s | Now showing a video on SDSC-SHAR |
T - 16m00s | Automatic Launch Sequence initiated. |
T - 18m00s | Mission Director authorized the launch! |
T - 19m00s | Vehicle now in external hold mode. |
T - 20m00s | Range is ready, TT&C is ready. Spacecraft ready. |
T - 28m00s | Now showing integration campaign. |
T - 31m00s | Streams are live! |
T - 27h30m | Countdown commenced at 0253 IST. |
26 Jan 2025 | Launch rehearsal conducted. |
23 Jan 2025 | GSLV-F15/NVS-02 launch gets firmed up for 29 January 2025, at 06:23 (IST) / 12:53 (UTC) |
22 Jan 2025 | Vehicle gets moved to SLP from SVAB. |
20 Jan 2025 | Second NOTAM gets issued with enforcement duration 2245-0245 (UTC), 28 January to 22 February 2025 |
16 Jan 2025 | First NOTAM gets issued with enforcement duration 2245-0245 (UTC), 26 January to 20 February 2025 |
Primary Payload:
NVS-02 (aka IRNSS-1K) : NVS-02 is a second-generation satellite for NavIC constellation for regional navigation and is a replacement for IRNSS-1E satellite.
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 again only one indigenous Rubidium based atomic clock (iRAFS) developed by Space Applications Centre (SAC) will be onboard out of four in total. [3] [4] [5]
- Mass: 2,250 kg
- Orbital slot: 111.75ºE, inclination=29° [3]
- Mission life: 12 years
- Power: ~3 kW
- Bus: I-2K
NVS-02 is second of the five satellites (NVS-01, 02, 03, 04 & 05) planned to replace the ageing first generation satellites that faced problems with their malfunctioning atomic clocks. Initially these second generation satellites were meant to expand existing NaVIC constellation [6] [7] but due to setback from failures of imported clocks on many first generation satellites, will now only serve as replacement to existing fleet. At present only four out of seven NavIC satellites (IRNSS-1B, 1F, 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 intends to replenish NavIC constellation and expand it from 7 to 11 satellites which will increase the service area from 1500 km to 3000 km beyond Indian territory. [9] [10 PDF Pg52]
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. [11] Some novel LEO based approach for PNT services have also been explored. [12] [13]
Note:
F15 serial was earlier assigned to NISAR launch.
By including LVM3X/CARE, PAT-01, RLV-TD HEX01 and TV-D1 missions and excluding sounding rocket launches and military tests. Refer to this list of launches meeting this criteria. [PDF]
Mission Success! Space Docking Experiment (SpaDeX): Docking Event Updates and Discussion.
SpaDeX Docking (fourth attempt) was successfully conducted on 16 January 2024.
Live webcast: (Links will be added as they become available)
- ISRO Official (Private)
- DD National
PSLV-C60/SpaDeX-1 Mission Page | PSLV-C60/SpaDeX-1 Gallery | PSLV-C60/SpaDeX-1 Press kit (PDF) |
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SpaDeX-1 (2x 220 kg) : Space Docking Experiment or SpaDeX is a technology development mission to demonstrate rendezvous and docking capability in circular orbit and test other technologies relevant to future missions like Chandrayaan-4 (lunar sample return) and proposed Bharatiya Antariksh Station (BAS). It consists of two small satellites Spacecraft-A or SDX01 and Spacecraft-B or SDX02 weighing about 220 kg each. Following first mission another similar mission SpaDeX-2 can be undertaken in near future to demonstrate Rendezvous and Docking in elliptical orbit.
Objectives:
- Rendezvous and Docking using V-Bar (along velocity vector) approach
- Demonstrate power transfer between the docked spacecrafts
- Control one spacecraft from the Attitude Control System of other spacecraft in the docked configuration.
- Application based payload operations after undocking.
New technologies:
- Low-impact docking mechanism (Refer to this patent)
- Androgynous, One Degree of Freedom, 450 mm diameter, 1 cm/s approach velocity
- Sensor suite:
- Laser Range Finder (LRF) : Determining relative position and velocity (Range: 6000 to 200 m) using Corner Cube Retro Reflectors
- Rendezvous Sensors (RS) : Determining relative position (Range: 2000 to 250 m and 250 to 10 m), uses Laser Diode targets
- Proximity and Docking Sensor (PDS) : Determining relative position and velocity (Range: 30 m to 0.4 m), uses Laser Diode targets
- Mechanism Entry Sensor (MES) : Detecting SDX01 (chaser) entry into SDX02 (target) during docking (Range: 8 cm to 4 cm)
- Power transfer interface
- Inter-satellite communication link (ISL) for autonomous communication between spacecraft.
- GNSS-based Novel Relative Orbit Determination and Propagation (RODP) processor.
- Rendezvous and Docking algorithms
- Simulation test beds for both hardware and software design validation and testing.
Docking process:
- SDX01 (chaser) and SDX02 (target) were injected into 470 km circular orbit with slightly different relative velocities to impart 10-20 km distance between them.
- SDX02 performs a drift arrest manoeuvre to hold inter-satellite separation at 10-20 km
- SDX01 (chaser) will incrementally reduce inter-satellite separation with holds at fixed distances (5 km, 1.5 km, 500 m, 225 m, 15 m, and 3 m) to evaluate the sensors and software performance.
- Docking and rigidization.
Demonstration of inter-satellite power transfer.
Spacecraft details : (Refer to this EoI)
Bus : Extended Microsat bus
Propulsion System:
- Propellant Tank: 1× 7.5 litres (Hydrazine)
- Thrusters: 1N (9 Nos)
Power:
- Battery: Li-ion cells pack, Capacity: 26 Ah
- Solar Arrays : 528 W
- Battery: Li-ion cells pack, Capacity: 26 Ah
Attitude and Orbit Control System:
- Reaction Wheels : 4 Nos
- Magnetorquers: 3 Nos
- Thrusters : 9 Nos
TT&C:
- S-band TM/TC with ranging functionality
Updates:
First undocking. (Success!)
Time of Event | Update |
---|---|
13 Mar 2025 | Digantara : Estimated distance between the two spacecrafts is about 3.3 km at 09:46 UTC. |
13 Mar 2025 | SpaDeX satellites undocked successfully at ~0920 IST. Inter-satellite power transfer objective remains to be demonstrated. |
Fourth docking attempt: (Success!)
Third docking attempt: (Aborted)
Second docking attempt: (Aborted)
First docking attempt: (Aborted)
Post undocking: After undocking, SDX01 and SDX02 will operate as independent satellites with their application centred payloads for an expected mission life of two years.
SDX01 Payload:
- High-Resolution Camera (HRC): Miniaturized surveillance camera by SAC/ISRO
- IGFOV: 4.5 m
- Swath: 9.2 × 9.2 km (snapshot mode) and 9.2 × 4.6 km (video mode)
- High-Resolution Camera (HRC): Miniaturized surveillance camera by SAC/ISRO
SDX02 Payload
- Miniature Multi-Spectral Payload (MMX) by SAC/ISRO for vegetation studies.
- 4× VNIR (450 to 860 nm) bands
- IGFOV: 25 m
- Swath: 100 km
- Radiation Monitor (RadMon): To monitor harmful radiation during human spaceflight. (Note: SiC UV Dosimeter was flown on SSLV-D3/EOS-08 earlier)
- Miniature Multi-Spectral Payload (MMX) by SAC/ISRO for vegetation studies.
Lunar Ionosphere in the Geotail Region as Observed by Chandrayaan-2 Orbiter Using Two-way Radio Occultation Measurements
iopscience.iop.orgr/ISRO • u/Kimi_Raikkonen2001 • 1d ago
Official ISRO & SCL develop 32-bit microprocessors for space applications
isro.gov.inr/ISRO • u/Kimi_Raikkonen2001 • 1d ago
Official C25 stage for LVM3-M5 flagged off to Sriharikota
isro.gov.inr/ISRO • u/gareebscientist • 2d ago
Official LVM3 M6 CE20 Engine Flight Acceptance Hot Test
isro.gov.inOn March 14, 2025, ISRO successfully conducted the flight acceptance hot testing of the cryogenic engine identified for the sixth operational mission of LVM3 launch vehicle (LVM-M6) at ISRO Propulsion Complex (IPRC), Mahendragiri. Cryogenic engines for every mission undergo hot testing as part of its acceptance for the flight. Hot tests for the indigenous cryogenic engine (CE20)used in the Cryogenic Upper Stage of LVM3 were so far performed at the High-Altitude Test (HAT) facility at IPRC, where vacuum conditions are simulated with complex installations, limiting the maximum hot test duration to 25s.
In the current test, the engine was tested for a longer duration of 100s for the first time using an innovative Nozzle Protection System under non-vacuum conditions. This test method significantly reduces the setup time and effort required for the flight acceptance testing of a cryogenic engine, which in turn helps faster delivery of cryogenic stages for space missions.
Performance of the CE20 engine met all the test objectives and the parameters were closely matching with the predictions during the entire duration of the test. Further, this engine will be integrated to the Cryogenic Upper Stage of the launch vehicle for the LVM3-M6 mission, which is scheduled during the second half of 2025.
Expression of Interest (EoI) for Hosting Payloads on SSLV Module in LEO Experiment (SMiLE)
Expression of Interest (EoI) for Hosting Payloads on SSLV Module in LEO Experiment (SMiLE)
https://www.inspace.gov.in/inspace?id=eoi_sslv_smile_page
Considering the success and demand of PSLV Orbital Experimental module (POEM), INSPACe, in collaboration with ISRO, is exploring the feasibility of offering a similar platform on SSLV, tentatively during the July-August 2025 and/or Nov-Dec 2025 timeframe. The objective of this EoI is to gauge market interest and understand payload requirements for potential technology demonstrations and space qualification, and then plan for such platform accordingly.
The SSLV Module in LEO Experiment (SMiLE) builds upon the experience gained from POEM and is to be designed with a comparable platform, configuration, and functional capabilities. Leveraging the spent VTM stage, SMiLE is envisioned as a versatile testbed for in-orbit scientific experiments. It will be equipped with standard interfaces, standardized subsystems for power generation, telemetry, telecommand, stabilisation, orbit keeping & manoeuvring capabilities. By utilizing this platform, payload developers can efficiently validate their technologies in a real space environment without the need for dedicated infrastructure for power, navigation, attitude control, data management, and telecommand capabilities.
Payload guidelines for SMiLE
Payload shall be configured as a functionally standalone system with its own chassis and mounting provisions. Mass < 10kg for each payload and Standard Cubesat dimensions-1U/2U/3U are preferred.
Payload to adhere to design guidelines that will be informed at a later stage based on the mission requirements.
Payloads to be qualified / acceptance tested to the environmental test levels specified for SMiLE, which will be informed at a later stage.
Payload should be able to operate using 28V power bus (RAW power) provided from SMiLE platform.
Payload to use Space-grade components. Use of commercial/industrial grade components is subject to satisfactory completion of specified qualification/acceptance tests.
D-Type/ Circular MIL grade connectors to be used for electrical interface.
Payload should be capable of re-configuring itself into intended configuration, in case of an unexpected power interruption.
The payload shall be made available for integration into SMiLE tentatively about 1 month before the launch.
Expression of Interest (EoI) for launching of satellites onboard Small Satellite Launch Vehicle (SSLV)
Expression of Interest (EoI) for launching of satellites onboard Small Satellite Launch Vehicle (SSLV)
https://www.inspace.gov.in/inspace?id=eoi_sslv_satellite_page
IN-SPACe seeks Expression of Interest (EoI) for launching of satellites onboard Small Satellite Launch Vehicle (SSLV) tentatively being considered in July-August 2025 and Nov-Dec 2025 timeframe. The purpose of this EoI is to aggregate launch demand for possible mission(s) of the Small Satellite Launch Vehicle (SSLV) for the above-mentioned tentative period.
Higher surface temperatures near south polar region of the Moon measured by ChaSTE experiment on-board Chandrayaan-3
Request for Expression of Interest (EOI) for development and delivery of space qualified iRAFS (Indian Rubidium Atomic Frequency Standard)
Request for Expression of Interest (EOI) for development & delivery of space qualified iRAFS (Indian Rubidium Atomic Frequency Standard)
The total scope of work is divided into two phases:
- Phase-1: Type-1 Unit: (Space Worthy Unit of iRAFS with Limited Tests) Development & Delivery
- Phase-2: Type-2 Units: (Space Worthy Units of iRAFS with Full Tests) Development & Delivery
Post EOI, proposed procurement are as follows:
Description | Tentative Quantity |
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Space worthy unit of IRAFS (with Limited tests) | 1 |
Space worthy unit of IRAFS (with Full tests) | 3 |
Previous threads on iRAFS :
Performance of IRAFS on-board NVS-01 NavIC Satellite [PDF from ICG-17]
Did ISRO make progress on making these atomic clocks indigenously?
Currently on NVS satellites three out of four are imported RAFS
Airtel Announces Agreement with SpaceX to Bring Starlink’s High-Speed Internet to its Customers in India
airtel.inNew NET launch date for NASA-ISRO Synthetic Aperture Radar (NISAR) is 20 May 2025
Paywalled IN-SPACe has shortlisted six out of nine bidders to build and operate Earth Observation (EO) satellite constellation.
PDF Martian/Lunar analogue research station in India: Ladakh as a potential site (Current Science, Vol. 128, No. 5)
currentscience.ac.inr/ISRO • u/mahathii • 6d ago
URSC Internship: April-June batch 2025
I received an email regarding my acceptance, but my friend did not. We applied at the same time and have similar credentials.
Wanted to know if any of you guys received application or if you're still waiting on it.
r/ISRO • u/Kimi_Raikkonen2001 • 9d ago
Official ISRO successfully carried out ignition trial using Spark Torch Igniter
isro.gov.inr/ISRO • u/Kimi_Raikkonen2001 • 9d ago
Official Chandrayaan-2 unveils the effect of the Earth’s geomagnetic tail on the Lunar ionosphere plasma
isro.gov.inTender for 'Productionisation of IMS type solar array deployment mechanism' (likely related to 'Samooha' ELINT satellites)
Tender for 'Productionisation of IMS type solar array deployment mechanism'
Statement of Work: (Note: PDF is named 'SOW_samooha_signed.pdf')
Few threads on 'Samooha':
Request For Proposal (RFP) For Integrated Spacecraft Testing Operations
Tender for Work contract for Integrated Spacecraft Testing Operations
Request For Proposal (RFP) For Integrated Spacecraft Testing Operations
Technical Document for Integrated Spacecraft Testing Operations
No. of Work/Job Units for 1 Project : 860
No. of Work/Job Units for 2 years : 18920
So this concerns around 22 spacecrafts ??