After a busy 2023, things have been quiet at Sriharikota, India’s spaceport. But silence at the spaceport does not imply that India’s space programme itself has been dormant. A lot has been happening since the Indian Space Research Organisation (ISRO) successfully landed the lander of its Chandrayaan 3 mission, Vikram, on the surface of the moon.

Prime Minister Narendra Modi has declared this date, August 23, India’s National Space Day.

Highlights in the last year

Aditya L1: India followed its lunar success with the successful launch of its solar science mission Aditya-L1 on September 2, 2023. The launch was the easiest part of the mission, onboard ISRO’s workhorse Polar Satellite Launch Vehicle (PSLV). The spacecraft executed a series of manoeuvres to move into an orbit around the first earth-Sun Lagrange point, called L1, on January 6, 2024. It completed its first orbit around L1 on July 2, 2024. In this time, it studied a solar storm in May 2024 together with observatories on the ground and spacecraft in lunar orbit.

Gaganyaan TV-D1: ISRO used a modified L-40 Vikas engine to build its Test Vehicle (TV) that it used to perform the first abort mission (TV-D1) on October 21, 2023, as part of its ‘Gaganyaan’ human spaceflight mission. The mission demonstrated the ability of the Crew Escape System (CES) to separate from the TV, take the crew module to safety, and the crew module’s ability to decelerate before splashing down in the Bay of Bengal. The crew module at the test’s end was recovered by the Indian Navy vessel INS Shakthi.

XPoSat: ISRO celebrated the new year with the launch of its X-ray Polarimeter Satellite (XPoSat) on January 1, 2024. The satellite will study how radiation is polarised and thus learn more about various sources of radiation in space. It is the second such space-based observatory after NASA’s Imaging X-ray Polarimetry Explorer (IPEX), launched in 2021. The two instruments on board XPoSat, called XSPECT and POLIX, began operating after launch on January 5 and 10.

INSAT-3DS: ISRO launched the meteorological satellite INSAT-3DS on February 17 onboard a Geosynchronous Satellite Launch Vehicle (GSLV). This mission was important to prove the vehicle’s credibility before the critical NASA-ISRO Synthetic Aperture Radar (NISAR) mission, now expected to be launched in the first quarter of 2025. This version of the GSLV had previously successfully launched the NVS-01 satellite in 2023.

RLV-TD: ISRO used a downscale version of the Reusable Launch Vehicle, called Pushpak, to conduct two landing experiments (LEX-02 and LEX-03) on March 22 and June 7 at its Aeronautical Testing Range in Challakere, Karnataka. The tests simulated landing conditions from space by dropping the Pushpak vehicle from a Chinook helicopter. While LEX-02 dropped Pushpak along its landing path, LEX-03 dropped it 500 metres to one side. The success of these tests gave ISRO the confidence to move on to the Orbital Return Flight Experiment (OREX).

SSLV: On August 16, ISRO launched the third and final development flight of the Small Satellite Launch Vehicle (SSLV), placing the EOS-08 and the SR-0 Demosat satellites in orbit. With two consecutively successful test flights, ISRO declared the SSLV’s development complete and green-lit its transfer to industry. EOS-08 carried three payloads: one for earth observation in the infrared range, one to demonstrate the use of reflections from a global satellite navigation system for earth observation, and one ultraviolet dosimeter and alarm to be tested ahead of their use in the Gaganyaan crew module.

ISRO roadmaps

After handing over operational responsibilities to NewSpace India, Ltd. (NSIL), ISRO has been prioritising research. In December 2023, ISRO Chairman S. Somanath announced a 25-year roadmap, until 2047, for Gaganyaan. It intersects with the lunar exploration roadmap in the form of an Indian landing on the Moon by 2040.

Mr. Somanath also shared a lunar exploration roadmap that includes — apart from an Indian on the moon — a lunar sample-return mission, a long-duration mission on the lunar surface, docking with NASA’s Lunar Gateway (under the Artemis programme), building habitats on the lunar surface.

Gaganyaan

One of ISRO’s primary focus areas of late has been to train its astronaut-candidates, or Gaganyatris, for spaceflight.

Prime Minister Modi revealed the candidates names on February 27: Wing Commander Shubhanshu Shukla and Group Captains Prashanth Nair, Ajit Krishnan, and Angad Pratap.

Earlier this month, Mr. Shukla and Mr. Nair travelled to the U.S. for advanced training leading up to one of them flying to the International Space Station (ISS). This is likely to be Mr. Shukla, with Mr. Nair his designated back-up. The mission will be conducted by Axiom Space, a private company, with inputs from NASA and onboard SpaceX’s launch vehicle and crew capsule. The flight is scheduled for 2025.

ISRO has also planned at least four more abort tests using its test vehicle before the historic crewed flight. The first uncrewed Gaganyaan mission is expected to fly in late 2024.

Mr. Somanath’s roadmap also includes plans to build an Indian space station called the ‘Bharatiya Antariksh Station’ (BAS) by 2035.

Next-generation Launch Vehicle

Since India is aspiring to both the BAS and a full-fledged lunar programme, it requires a new launch vehicle that can deliver heavier payloads per launch than its PSLV or GSLV rockets. This is set to be ISRO’s Next Generation Launch Vehicle (NGLV).

The organisation has set up a team led by Project Director S. Sivakumar, which submitted a project report to the Union Cabinet in February with a specific request for funding and details of the NGLV, including manufacturing requirements.

ISRO has planned for NGLV to be a three-stage launch vehicle powered by a semi-cryogenic engine, a liquid engine, and a cryogenic engine. ISRO doesn’t plan to continue the use of the GSLV once the NGLV is ready. The PSLV on the other hand is already under production by a private consortium led by Larsen & Toubro and Hindustan Aeronautics, Ltd.

But until then, ISRO is working on developing the semi-cryogenic engine for the LVM-3 rocket — another name for the GSLV Mk III — to enhance its launch capability. On May 2 and 21, it successfully tested the engine’s pre-burner ignition test article in important milestones.

NSIL missions

ISRO is focusing on research because the NSIL has been tasked with conducting missions and chaperoning commercial activities. On May 1, ISRO transferred all commercial activities related to Indian Remote Sensing satellite data and products to the NSIL.

The NSIL signed an agreement with SpaceX to launch the GSAT-20/GSAT-N2 satellite, its second demand-driven satellite. LVM-3 is currently not capable of launching this 4,700-tonne machine. SpaceX is expected to launch it in August 2024 from Cape Canaveral, Florida.

On May 10, the NSIL also released a request for qualification for the production of LVM-3 through a public-private partnership and signed a dedicated launch service agreement with an Australian private space company to launch the SSLV.

Private space missions

Private company Agnikul Cosmos successfully launched its SoRTeD-01 vehicle from its launch pad at the Satish Dhawan Space Centre in Sriharikota on March 21. This was the first launch of a vehicle powered by a semi-cryogenic engine as its first stage from Indian soil.

Skyroot Aerospace is progressing towards the launch of its launch vehicle, Vikram 1. It had previously pressure-tested its solid-fuel engines between May and July 2024 and launched a test vehicle called Vikram S from Sriharikota on November 18, 2022.

Dhruva Space and Bellatrix Aerospace flew their experiments on the fourth and final stages of the PSLV-C58 mission on January 1. (In this mission, the fourth stage turned itself into a small satellite, giving the payloads onboard an orbiting platform to conduct their studies).

IN-SPACe

In the last year, there have been several notable policy updates and licences issued by India’s new space regulator, IN-SPACe. Most importantly, it released the ‘Norms, Guidelines, and Procedures for Authorisation of Space Activities’ on May 3.

It also granted the country’s first satellite broadband licence to Eutelsat OneWeb on November 21, 2023, and granted the first licence for a ground station as a service, to be provided by Dhruva Space on July 15.

Finally, on February 21, the Government of India amended its foreign direct investment (FDI) policy to allow 100% direct FDI in all space and spaceflight segments except for a 74% ceiling in satellite manufacturing and operations and 49% in launch infrastructure.

Pradeep Mohandas is a technical writer and space enthusiast in Pune.

An illustration of Chandrayaan-3’s Pragyan rover roaming on the lunar surface. Photo: X/@chandrayaan_3 via PTI

Chandrayaan-3’s Pragyan rover has confirmed the presence of sulphur on the moon’s surface, near its south pole, and is still searching for hydrogen, the Indian Space Research Organisation said on Tuesday.

The Laser-Induced Breakdown Spectroscopy (LIBS) instrument onboard the Chandrayaan-3’s rover has made the first-ever in-situ measurements on the elemental composition of the lunar surface near the south pole. “These in-situ measurements confirm the presence of Sulphur (S) in the region unambiguously, something that was not feasible by the instruments onboard the orbiters,” ISRO said. “Search for Hydrogen (H) is underway,” it posted on X (formerly Twitter).

Laser pulse technique

The LIBS is a scientific technique that analyses the composition of materials by exposing them to intense laser pulses. A high-energy laser pulse is focussed onto the surface of a material, such as a rock or soil, and generates an extremely hot and localised plasma. The collected plasma light is spectrally resolved and detected by charge coupled devices. Since each element emits a characteristic set of wavelengths of light when in a plasma state, the elemental composition of the material can be determined in this way.

“Preliminary analyses, graphically represented, have unveiled the presence of Aluminum (Al), Sulphur (S), Calcium (Ca), Iron (Fe), Chromium (Cr), and Titanium (Ti) on the lunar surface. Further measurements have revealed the presence of manganese (Mn), silicon (Si), and oxygen (O). Thorough investigation regarding the presence of Hydrogen is underway,” ISRO said.

The LIBS payload was developed at ISRO’s Laboratory for Electro-Optics Systems in Bengaluru.

The graph of temperature variation on lunar surface. Twitter/@isro

ISRO on August 27 released a graph of the temperature variation on lunar surface with increase in depth measured by the ChaSTE payload onboard Chandrayaan-3’s Vikram lander module.

According to the space agency, Chandra’s Surface Thermophysical Experiment (ChaSTE) measured the temperature profile of the lunar topsoil around the south pole, to understand the thermal behaviour of the Moon’s surface.

“Here are the first observations from the ChaSTE payload onboard Vikram Lander. ChaSTE measures the temperature profile of the lunar topsoil around the pole, to understand the thermal behaviour of the moon’s surface,” ISRO said in an update on ‘X’, formerly Twitter.

The payload has a temperature probe equipped with a controlled penetration mechanism capable of reaching a depth of 10 cm beneath the surface.

“The probe is fitted with 10 individual temperature sensors. The presented graph illustrates the temperature variations of the lunar surface/near-surface at various depths, as recorded during the probe’s penetration. This is the first such profile for the lunar south pole. Detailed observations are underway,” it said.

The payload was developed by a team led by the Space Physics Laboratory (SPL) of ISRO’s Vikram Sarabhai Space Centre (VSSC) in collaboration with Physical Research Laboratory (PRL), Ahmedabad.

India on Wednesday scripted history as ISRO’s ambitious third Moon mission Chandrayaan-3’s Lander Module (LM) touched down on the lunar surface, making it only the fourth country to accomplish the feat, and first to reach the uncharted south pole of Earth’s only natural satellite.

The indigenous rover’s exploration of the lunar surface began a day after India became the fourth country to successfully land on the moon, spurring euphoric celebrations at ISRO and around the country. Photo: ISRO

Hours after the Pragyan lunar rover rolled out from the Vikram lander and took its first “walk on the moon” in the early hours of Thursday, the Indian Space Research Organisation (ISRO) said that the historic Chandrayaan-3 Mission was running on schedule, with all systems working normally. Instruments aboard the lander and rover will now study the moon’s mineral composition and the seismic activities in its atmosphere, according to ISRO chairman S. Somanath.

The indigenous rover’s exploration of the lunar surface began a day after India became the fourth country to successfully land on the moon, spurring euphoric celebrations at ISRO and around the country.

‘Walk on the moon’

“Chandrayaan-3 ROVER: Made in India Made for the MOON! The Ch-3 Rover ramped down from the Lander and India took a walk on the moon!” ISRO posted on social media platform X, on Thursday morning.

President Draupadi Murmu had made the first announcement of the rover’s successful deployment at 7 a.m. “Its rolling out a few hours after the landing of Vikram marked the success of yet another stage of Chandrayan 3. I look forward with excitement, alongside my fellow citizens and scientists to the information and analyses that Pragyan will acquire and enrich our understanding of the moon,” she posted.

‘All systems are normal’

Later in the evening, ISRO added an update on mission operations and the payloads aboard the lander. “Chandrayaan-3 Mission: All activities are on schedule. All systems are normal. Lander Module payloads ILSA, RAMBHA and ChaSTE are turned ON today. Rover mobility operations have commenced. SHAPE payload on the Propulsion Module was turned ON on Sunday,” it posted.

Dr. Somanath confirmed that the rover movement is happening and working very well. He told the Press Trust of India that there are two instruments in the rover and three instruments on board the lander, and all of them have been switched on sequentially.

“They will study basically the mineral composition of the moon, as well as the atmosphere of the Moon and the seismic activities there,” he added.

‘Perfect landing’

Dr. Somanath also said that the Chandrayaan-3 spacecraft’s lander Vikram had touched down on the moon’s surface well within the area identified for the purpose.

“(The lander landed) perfectly in the intended site. The landing location was marked as 4.5 km x 2.5 km — I think on that space, and the exact centre of that was identified as the location of landing. It landed within 300 metres of that point. That means it is well within the area identified for landing,” he said.

(with PTI inputs)

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A dish antenna is seen inside the ISRO Telemetry Tracking and Command Network (ISTRAC) facility on August 23, 2023 in Bengaluru.
| Photo Credit: Getty Images

With Vikram, the lander module of Chandrayaan-3, successfully landing on the surface of moon on August 23, the focus has now moved to the rover in its belly, Pragyan.

The officials at the Mission Operations Complex (MOX) at ISRO Telemetry, Tracking, and Command Network (ISTRAC) are readying to roll out the rover, which will carry out in-situ chemical analysis of the lunar surface during the course of its mobility.

“The Pragyan rover may come out in the next few hours or it may take one day also to come out depending on the conditions,” ISRO Chairman S. Somanath said.

He said that once out, the rover would carry out two important experiments. It has two payloads — the LASER Induced Breakdown Spectroscope (LIBS) and the Alpha Particle X-ray Spectrometer (APXS). The objectives of the LIBS are to conduct qualitative and quantitative elemental analysis and to derive the chemical composition and infer mineralogical composition to further our understanding of the lunar surface.

The APXS will determine the elemental composition of lunar soil and rocks around the landing site.

The team behind Chandrayan-3’s success

Soon after the ISRO achieved the historic feat of landing on the lunar south pole, Mr. Somanth introduced the key members who enabled India to achieve the task flawlessly.

P. Veeramuthuvel, Project Director, Chandrayaan-3, said, “It is a great moment of happiness, it gives me immense satisfaction on achieving this goal as Project Director of this mission. The entire mission operations from launch till landing happened flawlessly as per the timeline and we have become the fourth country to demonstrate the soft landing on the moon and the first country to go to the south pole of the moon.”

Sreekanth, Mission Director, Chandrayaan-3, said, “It gives me immense pleasure to be part of Chandrayaan-3 and as Mission Director, I would like to thank each and every team member who has supported in carrying out all the mission operations flawlessly.”

Calling it a memorable moment, Kalpana K., Associate Project Director, Chandrayaan-3 said, “We have achieved our goal flawlessly after rebuilding our spacecraft. It has been breath in and out for our team.”

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M. Sankaran, Director of U.R. Rao Satellite Centre, said, “Today we have achieved what we set out to achieve in 2019. It was delayed by four years but we have done it.” He was referring to the failed landing of Chandrayaan-2 in 2019.