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Why ‘Naughty Boy’ satellite launch, ISRO's 1st success this year, is a giant leap for India
EOS-05 would enable continuous monitoring of India and nearby regions, ISRO chairman V Narayanan has said.
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The launch of ISRO’s GSLV-F17 carrying EOS-05 was an important milestone for India’s space programme. Friday’s launch of the ‘Naughty Boy’ satellite also saw a lot of firsts for the country.
EOS-05 is the heaviest ever launched by a GSLV and will become India’s first dedicated imaging satellite to operate from geosynchronous orbit once it reaches its operational orbit.
Prime Minister Narendra Modi called the launch “yet another outstanding achievement by ISRO and a proud moment for our nation”. The PM said it reflected the “excellence, innovation and growing capabilities” of India’s space sector.
Deep Dive
ISRO Chairman V Narayanan described it as a “historical achievement”.
ALSO READ | ISRO's GSLV-F17 carrying EOS-05 earth observation spacecraft takes off from Sriharikota
Here is why the mission is so significant.
1. India is putting an Earth-imaging satellite in a much higher orbit
Most Earth observation satellites operate from low Earth orbit (LEO), typically hundreds of kilometres above the planet. EOS-05 is different.
The satellite was injected into a sub-geosynchronous transfer orbit after Friday’s launch and will use its own propulsion system to reach its required operational orbit at roughly 36,000 km above the Earth.
At that altitude, a satellite’s orbital period matches the Earth’s rotation. This allows it to remain over the same broad region and repeatedly observe it.
That gives EOS-05 an important advantage: it can provide frequent observations of large areas rather than having to pass over a location only at intervals, as is the case with many lower-orbiting Earth observation satellites.
The mission is designed to provide real-time or near real-time imaging of large-area regions at frequent intervals, helping with applications such as agriculture, disaster management and the monitoring of cyclones, cloudbursts and thunderstorms.
2. It is the heaviest satellite ever launched by a GSLV
At 2,367 kg, EOS-05 is the heaviest satellite ever launched by a GSLV vehicle, according to Narayanan.
That makes Friday's mission an important demonstration of the launch vehicle’s growing capability.
The GSLV-F17 is a 51.7-metre-tall, three-stage rocket with a lift-off mass of about 420.5 tonnes. Its third stage uses a cryogenic engine, and the vehicle has a said payload capability of around 2,250 kg for the relevant orbit class.
Yet Narayanan said the vehicle exceeded its predicted performance during Friday’s mission.
The predicted injection altitude was around 29,934 km, while the mission achieved approximately 31,000 km.
The satellite will now use its own propulsion system to raise its orbit to the required operational altitude.
Narayanan said EOS-05 has an assured lifetime of seven years, while expressing confidence that it could function for more than nine years.
“We will take it to the required orbit using the propulsion system of the satellite, and the assured lifetime of the satellite is seven years. I am confident it will work for more than nine years,” he said.
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3. Its imaging capabilities could be crucial for agriculture and disasters
EOS-05 has been described as a state-of-the-art Earth observation satellite capable of imaging across visible, infrared, multispectral and hyperspectral bands.
That is significant because different wavelengths can reveal different characteristics of the Earth’s surface and atmosphere.
The satellite is expected to provide imagery that can be used for agriculture, forestry and monitoring water bodies, apart from disaster management.
Its ability to repeatedly observe large areas from geosynchronous orbit could be particularly useful during rapidly developing events.
ISRO has said the mission will support disaster warning, cyclone monitoring and the monitoring of cloudbursts and thunderstorms.
The satellite has been called the “eye in the sky” by a senior scientist involved in the mission. But Narayanan has made it clear that EOS-05 should not be viewed as a “spy satellite”.
He said the Earth observation satellite would be capable of continuously scanning India, underlining its role in providing high-frequency Earth observation data.
ALSO READ | GSLV-F17 rocket successfully places heaviest earth observation satellite into intended orbit: ISRO
4. It is a major recovery for GSLV after the 2021 failure
The mission's significance also lies in what came before it.
EOS-05 is a follow-up to the unsuccessful GSLV-F10/EOS-03 mission of August 12, 2021. That mission failed after the cryogenic upper stage did not ignite as planned after liftoff from Sriharikota.
An analysis of post-flight data indicated that an anomaly in the cryogenic upper stage led to the failure.
The successful GSLV-F17 mission therefore represents more than the deployment of another satellite. It demonstrates the progress made by ISRO in improving the performance and reliability of the GSLV and its cryogenic propulsion system.
Narayanan recalled that the first GSLV launch carried a payload of 1,536 kg. Since then, ISRO has gradually improved the vehicle’s performance by optimising its structural mass and improving its propulsion systems.
“Today, we have injected the heaviest satellite, a 2,367-kg satellite, using this launch vehicle,” he said.
The achievement is particularly important after another setback earlier this year. On January 12, the PSLV-C62 mission, carrying 16 satellites, failed to place them in their intended orbits after an anomaly in the vehicle’s third stage.
Friday’s success thus provides a morale boost for the space agency as it enters a busy period of launches.
5. It strengthens India’s ability to generate its own strategic Earth data
Perhaps the biggest significance of EOS-05 lies in its potential use as a source of high-frequency Earth observation data for national applications.
Once operationalised, Narayanan said, it will become India’s first dedicated imaging satellite from geosynchronous orbit, providing “strategic data” for the country.
That data can have applications ranging from agriculture and water-resource management to disaster response and weather-related monitoring.
The ability to observe India repeatedly from a fixed orbital position also gives the country a capability that complements its existing constellation of Earth observation satellites in lower orbits.
“This is a great achievement for our country’s space programme because this is the first Earth observation satellite that is going to be placed on the geo platform for national activities,” Narayanan said.
What comes next?
Friday's launch was only the beginning of the EOS-05 mission. The satellite was placed in a sub-geosynchronous transfer orbit and will undergo orbit-raising manoeuvres using its own propulsion system before being positioned in its required operational orbit.
The launch also comes as ISRO prepares for an ambitious year ahead. Narayanan said the agency is targeting six more launches during the current financial year.
Among the major programmes on the horizon is Gaganyaan, India’s human spaceflight programme.
Narayanan said around 8,000 tests had been completed for Gaganyaan, which he described as a technology-intensive mission in which human safety remains the top priority.
ISRO plans three uncrewed missions before crewed missions, with the first uncrewed Gaganyaan mission being prepared for launch this year.
Unlike conventional satellite missions, the human-rated launch vehicle and associated systems require extensive testing because the safety of astronauts is directly involved.
Against that backdrop, the successful GSLV-F17/EOS-05 launch is important not just for the satellite it carried, but also for the confidence it gives ISRO as it takes on increasingly complex missions.
