ISRO EOS-05 Reaches Geosynchronous Orbit: What Happens Next?
Latest Update - September 9, 2026
ISRO has successfully accomplished yet another milestone with its EOS-05 Earth observation satellite. The satellite has completed its third and final orbit raising manoeuvre, placing it in its intended geosynchronous position.The satellite completed its third and final orbit raising manoeuvre to place it in its intended geosynchronous position.
The EOS-05 was carried by GSLV-F17 from Satish Dhawan Space Centre, Sriharikota on 4 September 2026. Upon launching, the spacecraft went through a series of orbit raising manoeuvres to bring it into its operational orbit.
EOS-05 Satellite has been successfully reaches its intended orbit.
The final manoeuvre to raise the orbit was successfully performed on September 7 at 8:57 PM IST.
Satellite's Liquid Apogee Motor (LAM) fired for 1247 seconds during the manoeuvre. ISRO said that the satellite's health was satisfactory after the manoeuvre and the spacecraft was in an estimated elliptical orbit of 34,903 km by 35,884 km.The satellite health is normal.
The orbital-raising portion of the mission just ended.
What is special about EOS-05?
EOS-05 is a geosynchronous Earth orbit Earth observation satellite.
A geosynchronous satellite may be maintained over about the same area of the earth as the earth rotates, unlike some Earth satellites which orbit the earth and pass over a given area on a periodic basis.
This is one important advantage to EOS-05 because it could enable frequent observation over large areas in the Indian sub-continent.
India's first earth observation satellite built for geosynchronous orbit.
How was EOS-05 put into its orbit?
Shortly after launch, the satellite did not go into its final orbit.
GSLV-F17 injected EOS-05 into its initial transfer orbit, before the satellite transferred itself to its operational orbit through a series of apogee engine burns.
The first big orbit boosting manoeuvre was on September 5th followed by another manoeuvre on September 6th.
The third and final manoeuvre was performed on 7 September to put Earth in the near circular orbit of 35884 km by 34903 km.
Why is EOS 05 important for India?
EOS-05 is likely to boost India's capacity for uninterrupted observation of the Earth.
The observations it makes can be useful in a number of applications such as:
- Disaster monitoring
- Monitoring cyclone and extreme weather events.
- Agriculture
- Forestry
- Water-resource monitoring
- Environmental monitoring
- Overview of fast changing events over large areas
As a geosynchronous satellite it can see wide areas of the Indian sub-continent more often that traditional earth observing satellites which only fly over a site at periodic intervals.
What Happens Next?
Putting an orbiter into its desired orbit is not the end of the mission.
ISRO will now conduct health checks and other checks of the spacecraft and payload, prior to the satellite's imaging systems now going into operational use.
Once the satellite is fully operational, the monitoring services offered by the satellite will be able to generate useful information for monitoring the Indian land, environment, weather-related events, etc.
Two-day launch window for GSLV-F17 and EOS-05 Mission.
ISRO has launched EOS-05 mission with its GSLV-F17 rocket.
The satellite was about 2,367 kg in weight, which was described as the heaviest satellite payload so far launched by the GSLV. This successful launch and orbital manoeuvring showcases the capabilities of India's launch system and satellite systems for the successful insertion of a large Earth observation satellite into the high orbit.
Final Takeaway
The successful arrival of EOS-05 in geosynchronous orbit is an important milestone for India's Earth-observation programme.
The satellite has now finished its main orbital adjustments and is undergoing tests before its images are turned on. EOS-05 will be able to provide frequent observations of Indian subcontinent once it is operational and will be useful for various application areas such as disaster monitoring, agriculture, environmental observation etc.
The mission is another move toward enhancing and expanding India's space-based Earth-observation capabilities.
Published on September 5, 2026
The GSLV-F17 EOS-05 mission has successfully added another important milestone to India's space programme. The Indian Space Research Organisation (ISRO) launched the GSLV-F17 rocket carrying the EOS-05 Earth observation satellite from the Satish Dhawan Space Centre in Sriharikota on September 4, 2026.
The rocket lifted off at 2:55 AM IST from the Second Launch Pad and successfully placed EOS-05 into a Sub-Geosynchronous Transfer Orbit (Sub-GTO). EOS-05 is India's first imaging satellite designed to operate from a geosynchronous orbit, enabling frequent observation of a large region of Earth.
GSLV-F17 EOS-05 Launch: Key Highlights
Mission Detail Information
- Mission GSLV-F17 / EOS-05
- Launch date September 4, 2026
- Launch time 2:55 AM IST
- Launch site Satish Dhawan Space Centre, Sriharikota
- Launch pad Second Launch Pad (SLP)
- Launch vehicle GSLV-F17 / GSLV Mk II
- GSLV flight number 19th
- Satellite EOS-05
- Satellite alternate name GISAT-1A
- Satellite type Earth observation
- Payload mass Approximately 2,367 kg
- Target orbit Sub-Geosynchronous Transfer Orbit (Sub-GTO)
- Nominal perigee 170 km
- Nominal apogee 28,934 km
- Inclination 19.28° ± 0.1°
- Launch azimuth 104°
- Rocket height 51.7 metres
- Liftoff mass 420.5 tonnes
- Number of stages 3
When Did GSLV-F17 Launch?
ISRO launched the GSLV-F17 carrying EOS-05 at 2:55 AM Indian Standard Time (IST) on Friday, September 4, 2026.
The launch took place from the Second Launch Pad at Satish Dhawan Space Centre (SDSC-SHAR), Sriharikota. ISRO's official launch information confirmed the 2:55 AM IST liftoff time.
Following liftoff, the mission successfully delivered EOS-05 into its planned Sub-GTO. Reports indicate that satellite injection occurred at approximately 3:14 AM IST.
What Is GSLV-F17?
GSLV-F17 is the 19th flight of India's Geosynchronous Satellite Launch Vehicle (GSLV).
The rocket used for this mission is part of the GSLV Mk II family. It uses a three-stage configuration consisting of a solid-fuel first stage with four liquid strap-on motors, a liquid-fuel second stage and a cryogenic upper stage.
According to ISRO, GSLV-F17 uses a 4-metre-diameter ogive composite payload fairing to protect the satellite during the early portion of the flight.
GSLV-F17 Rocket Specifications
- Rocket height: 51.7 metres
- Liftoff mass: 420.5 tonnes
- Stages: 3
- Payload fairing: 4-metre-diameter ogive composite configuration
- Configuration: S139 + 4 L40H + GL40HT + CUS15
ISRO lists the three major stages as:
- First Stage – GS1
- Second Stage – GS2
- Third Stage – GS3
GSLV-F17 Propulsion System
GSLV-F17 employs three different propulsion technologies in its three stages.
First Stage – GS1
The first stage is made of the S139 solid motor along with four liquid strap-on L40H motors.
The propellant used in the S139 is HTPB, in the L40H motors it's UH25 and N2O4.
ISRO's mission brochure indicates that the S139 carries some 138 tonnes of propellant, and the four L40H strap-ons have a total propellant mass of some 170 tonnes.
Second Stage – GS2
The second stage is called GL40HT.
It operates with propellants UH25 and N2O4 and has a propellant mass of some 42 tonnes.
Third Stage – GS3
The upper cryogenic stage used is a CUS15 (cryogenic upper stage).
It is fueled by liquid hydrogen (LH2) and liquid oxygen (LOX). The propellant mass on the stage is about 15 tonnes.
What Is EOS-05?
ISRO's EOS-05 is a sophisticated satellite designed for Earth observation.
The satellite also has the designation of GISAT-1A. It has the major feature of being the first imaging satellite of India to be placed in a geosynchronous orbit.
This is of importance since the majority of the traditional Earth observation satellites are in lower orbits and pass over a given area on the ground multiple times. A geosynchronous satellite is one that can be synchronized to the rotation of the Earth allowing it to repeatedly observe a wide area.
Hence, EOS-05 is conceived to be capable of making much more frequent observations over Indian region and its neighbourhood.
EOS-05 Satellite Specifications
The mass of the primary payload on GSLV-F17 was around 2,367 kg.
Important EOS-05 features
- Earth observation spacecraft
- Approximately 2,367 kg payload
- This spacecraft can be used for geosynchronous-orbit imaging.
- Designed to be used for repeated observation of large geographic regions
- Specially developed for Earth observation applications.
- Can monitor environmental and natural events.
- Provides an important capability for rapid regional observation
These reports have raised hopes for the mission's agricultural, disaster management, environmental monitoring and strategic observation applications.
Which orbit will EOS-05 be operating in?
GSLV-F17 did not directly inject EOS-05 into its end-of-mission position.
Instead, ISRO aimed for a Sub Geosynchronous Transfer Orbit (Sub-GTO).
The official mission brochure gives the following nominal orbital parameters:
- Perigee: 170 km
- Apogee: 28,934 km
- Argument of perigee: 178° ± 0.5°
- Inclination: 19.28° ± 0.1°
- Launch azimuth: 104°
The satellite can then raise and manoeuvre itself using its own thrusters and orbital techniques to reach its operational geosynchronous orbit.
A geosynchronous orbit is at an altitude of ~35,786 km over the equator of the Earth. Synchronising an orbit with the rotation of the Earth would allow a satellite to repeatedly observe the same wide region at this altitude.
Why Is EOS-05 Important for India?
The main importance of EOS-05 is that it is carrying an imaging satellite in a geosynchronous orbit.
A normal earth observation satellite revolves fast around the earth in an elliptic orbit with a mean altitude of about 680 km. It can be very detailed but doesn't stay over the same area all the time.
EOS-05 does not.
The satellite's orbit is, at a much higher geosynchronous orbit, allowing it to repeat its observations of a large area. This can be helpful when it's important to get updates quickly.
1. Disaster Management
EOS-05 can be used to support natural disaster monitoring and the monitoring of other fast-changing phenomena.
Applications may involve flooding, cyclonic disasters, fire disasters and other major disasters.
2. Agriculture
Regular observations of the Earth can be used to monitor agriculture and enable authorities to track changes over vast areas.
3. Weather and Environmental Monitoring
Periodic or regular monitoring can be helpful for environments and other Earth science uses.
4. Strategic Observation
The satellite's orbit around the Earth from geosynchronous orbit also means it has the potential to repeatedly observe large areas of the Earth, thereby adding strategic and national security-related value to the satellite's Earth observation capabilities.
But, primarily, EOS-05 is an Earth observation and imaging satellite as per the official mission description of ISRO.GSLV-F17 and EOS-05 Mission Sequence
The mission unfurled as a usual multi-stage flight of GSLV.
Step 1: Liftoff
GSLV-F17 started its journey from Second Launch Pad at 2.55 AM IST on September 4, 2026.
Step 2: First-Stage Flight
The major initial thrust required to lift the 420.5-tonne vehicle was supplied by the solid S139 core and four liquid L40H strap-ons.
Step 3: Second-Stage Operation
The split of the first stage elements allowed the liquid GL40HT second stage to continue to accelerate the vehicle.
Step 4: Upper Stage in cryogenic environment
The CUS15 upper stage with cryogenic propulsion was used to deliver the high-energy injection necessary to attain the mission's desired transfer orbit.
Step 5: EOS-05 Separation
The satellite was successfully injected into its planned Sub-GTO.
ISRO has said that the mission accomplished its primary goal.
GSLV-F17 is ISRO's 19th GSLV Flight.
ISRO says that the EOS-05 mission is the 19th flight of India's GSLV.
The last GSLV mission was GSLV-F16/NISAR in July 2025. The GSLV-F17 mission is, thus, another significant milestone on the path of India using the GSLV Mk II on its missions towards heavier spacecraft in geosynchronous-class orbits.
The data records from EOS-05 and from the Earlier GISAT-1 Mission.
EOS-05 is closely related to the previous India's GISAT-1/EOS-03 project.
In August 2021, the previous GSLV-F10 mission with EOS-03 failed. ISRO's "Failures" column in the launch record mentions the GSLV-F10/EOS-03 mission as a failure.
The GSLV-F17/EOS-05 mission is India's latest attempt after the previous one and it is an indication of its perseverance on the mission of creating geosynchronous Earth-imaging capabilities.
Why GSLV-F17 is special?
There are several reasons why this mission is important:
- First: This is the 19th flight with GSLV.
- Second: It has successfully launched a nearly 2367-kg Earth observation satellite.
- Third: EOS-05 is India's first imaging satellite which is designed for geosynchronous orbit.
- Fourth: It shows GSLV's capability to place a relatively heavy Earth observation satellite in a Sub-GTO.
- Fifth: The concept of operation for the satellite will be geosynchronous so that frequent observations of a large geographic region can be made.
The final status of GSLV-F17 EOS-05 Mission is announced.
The GSLV-F17/EOS-05 mission was successfully completed on 4th Sept 2026.
The rocket successfully launched EOS-05 into the planned Sub-Geosynchronous Transfer Orbit from the Second Launch Pad at Satish Dhawan Space Centre, Sriharikota at 2:55 AM IST.
ISRO says EOS-05 is the country's first-ever imaging satellite from geosynchronous orbit, which is a pivotal event in the country's earth observation programme.
The mission is also a big milestone for GSLV and will boost India's space-based Earth observation capacity, especially for frequent observation of vast areas.
Conclusion
This is a crucial event of India's space programme, that of the GSLV-F17 rocket, carrying the EOS-05. The mission was successfully launched at 2:55 AM IST on September 4, 2026, and placed the Earth observation satellite EOS-05 of about 2,367 kg in the desired Sub-GTO.
This mission is especially important as India's first imaging satellite to operate in geosynchronous orbit is EOS-05. It has the capability of repeated observation of a large area, which will enable a wide range of applications including disaster management, agriculture, environmental observation and strategic observation.
The 19th flight of the Indian Geophysical Launch Vehicle (GSLV) with its 51.7-metre GSLV-F17 and 420.5-tonne payload successfully completed the mission, which was another major stride in the country's developing capabilities for Earth observation and launch-vehicle operations.
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