From Reusable Launch Vehicle To Gaganyaan, ISRO Launches To Look Forward To This Year After SSLV Success

India achieved success with the launch of its new, and the sixth-ever, rocket — the small satellite launch vehicle (SSLV).

It was the perfect start for India’s 2023 in space — a year that seems packed with important space developments for India.

Indian Space Research Organisation (ISRO) chairman S Somanath provided a glimpse of what’s to come this year in his concluding address at the Satish Dhawan Space Centre-Sriharikota Range (SDSC-SHAR) on 10 February.

Launch Of OneWeb Satellites

On ISRO’s next project, 36 OneWeb satellites will fly on India’s heaviest rocket until they are deposited into their intended orbits.

The rocket in question is the geosynchronous satellite launch vehicle-mark 3 (GSLV-Mk3), rechristened as launch vehicle-mark 3 (LVM3).

LVM3 delivered the first batch of 36 OneWeb satellites on its debut commercial flight, and only its second operational mission, on Diwali day last year. It thus became a proper option on the global commercial launch market.

OneWeb is a low-Earth orbit (LEO) satellite communications company from the United Kingdom (UK). India’s Bharti Enterprises is a major investor and shareholder in OneWeb and Sunil Bharti Mittal is the executive chairman of OneWeb.

The UK company has contracted NewSpace India Limited (NSIL), the commercial arm of ISRO, for the LVM3 satellite missions. The deal is for the launch of 72 satellites across two missions for a fee of over Rs 1,000 crore.

NSIL will execute the LVM3-M3/OneWeb India-2 mission, which is expected to lift off mid- March. The 36 satellites that are set to fly are in India awaiting integration (at the time of writing).

OneWeb is building a constellation of 648 satellites to provide high-speed, low-latency connectivity worldwide. It has 542 satellites in space already. A successful ISRO mission will take that tally to 578 satellites.

Next PSLV Launch In March-End

Hot on the heels of the successful SSLV-D2 mission, ISRO went to work right away to prepare the next polar satellite launch vehicle (PSLV) mission, PSLV-C55.

It will be a commercial launch mission, to be executed by NSIL, with liftoff most likely by the end of March.

“The launch campaign will commence today by the placing of the rocket at the launch pedestal in a new facility that is going to be used this time,” Dr Somanath said on 10 February.

PSLV-C55 will be the 57th mission on India’s workhorse launcher. In the previous PSLV mission, the Earth-observation satellite Oceansat-3 and eight co-passenger satellites were lifted off minutes before noon on 26 November last year and injected into their respective orbits.

That mission was especially notable because three satellites from Indian private players Pixxel (Anand) and Dhruva Space (Thybolt 1, Thybolt 2) flew on that mission.

Landing Demonstration Of The Reusable Launch Vehicle

“Currently, the teams are at the landing site at Chitradurga (Karnataka). We are hoping that in few days of time, everything will be alright, the initial preparations will be alright, and we’ll be able to do the landing demonstration,” Somanath said at SDSC-SHAR.

The ISRO chairman said last September at the Bengaluru Space Expo 2022 that the cost of placing a 1-kg payload into orbit had to be brought down from the current range of $10,000 to $15,000, to $5000 to $1,000. 

“Only way to do that is to make the rocket reusable,” he said.

“India’s launch costs are lower, largely due to cheap, skilled engineers. But India cannot bank on that factor alone for long. As the Indian economy grows, the wages will start to rise and the wage differential will begin to narrow down. Reusability is the only factor that will ensure competitiveness and environmental sustainability,” Srinivas Prasad Ganti writes in Swarajya, on why reusability matters.

India’s space agency has been working on the Reusable Launch Vehicle – Technology Demonstrator (RLV-TD) for years. It is the precursor to a fully reusable launch vehicle.

“The configuration of RLV-TD is similar to that of an aircraft and combines the complexity of both launch vehicles and aircraft,” says ISRO.

Hypersonic flight, autonomous landing, and powered cruise flight are the technologies that will be tested on the winged RLV-TD before it ultimately becomes the first stage of India’s reusable two-stage orbital launch vehicle.

India accomplished the RLV-TD HEX-01 (hypersonic flight experiment) mission in May 2016, testing various technologies for a suborbital flight and landing at sea.

The next step is RLV-LEX (landing experiment). It will demonstrate approach and autonomous landing on a runway.

“In LEX, the RLV will be carried using a helicopter to an altitude of 3-5 km and released at a distance of approximately 4-5 km ahead of the runway with a horizontal velocity,” the RLV mission page on the Vikram Sarabhai Space Centre says.

After the release, the RLV will glide and make its way towards the runway and then carry out conventional autonomous landing at a defence airfield near Chitradurga in Karnataka.

Gaganyaan Programme

“We are hoping to have the test flight, test vehicle missions of showing abort and recovery capability of the crew module to be demonstrated in one mission today (10 February) and also followed by one more launch this year itself, and also trying for the unmanned mission if these two missions go very well” — S Somanath.

ISRO and the Indian Navy on 7 February carried out initial recovery trials of the crew module at the Water Survival Test Facility (WSTF) in Kochi, Kerala, as part of Gaganyaan mission preparations.

Safe recovery of the crew will be the critical final step as part of India’s maiden human spaceflight mission. Trials will move from a closed pool (the WSTF trial) to a harbour and eventually to the open sea.

The Gaganyaan programme aims to demonstrate India’s human spaceflight capability. A three-member crew will be launched to an orbit of 400 km for a three-day mission before being brought back safely down to Earth. They will land at sea in India.

Prime Minister Narendra Modi announced the programme in his Independence Day address of 2018.

The crewed launch is set to happen in the fourth quarter of 2024.

 The “unmanned mission” Somanath referred to on 10 February, is scheduled for the last quarter of 2023. It is set to be followed by another uncrewed mission in the second quarter of 2024.

New NavIC satellites

The GSLV will be called on for its services on more than one occasion this year. In one mission, it will lift off with the new series of NavIC satellites.

NavIC is short for “Navigation with Indian Constellation.” Its earlier name, the Indian Regional Navigation Satellite System (IRNSS), describes what it is.

The system helps with the positioning, navigation, and timing requirements of the nation. It does so, thanks to a constellation of seven satellites and a round-the-clock network of ground stations.

NavIC has offerings for civilian and strategic users — Standard Position Service and Restricted Service respectively. Its coverage area includes India and an area stretching out 1,500 km beyond the country’s borders.

While its services are provided in the L5 (1176.45 MHz) and S (2498.028 MHz) bands, the new NavIC satellites to go up in orbit will broadcast SPS signals in the L1 (1575.42 MHz), L5, and S bands.

Indigenous digital codes, designed jointly by ISRO and the Indian Institute of Science, will be used in the new L1 signal. The introduction of the L1 signal will increase NavIC’s use in the civilian space, and also by ships and aircraft travelling far from the country’s borders.

On the sidelines of the India Space Congress, Somanath told PTI in late-October last year that ISRO was in talks with the government to launch an additional 12 satellites in the medium-Earth orbit (MEO).

This will expand the reach of NaVIC and “a regional to global changeover will be very fast” as a result of a GEO-MEO constellation (GEO stands for geostationary orbit).

In addition to the launch of NavIC satellites, the ISRO chief spoke of a “repeat launch of GSLV” this year “prior to the launch of NISAR, which is scheduled by the end of this year.”

NISAR, NASA-ISRO Low-Earth Observatory

The idea for the mission came from the National Academy of Science’s 2007 survey ("decadal survey") of Earth-observational priorities for the 2010-20 decade.

Making measurements and extracting insights about ecosystems, deformation of Earth's crust, and cryospheric sciences were identified as a top priority in the survey.

The joint satellite mission will use radar to take a good, close look at many Earth processes — earthquakes, volcanoes, landslides, sea ice and glacier movement, among many others — over all the land masses, including the polar cryosphere and the Indian Ocean region.

NISAR will carry two types of synthetic aperture radar (SAR) — the S-band SAR developed by ISRO and the L-band SAR developed by NASA. The letters "S" and "L" in this context represent the wavelengths of their signal, which is 9 cm and 24 cm respectively.

The satellite is expected to provide "an unprecedented ability to look at how Earth’s surface is changing,” in the words of NISAR project scientist Paul Rosen.

NISAR, set to be the world’s most expensive imaging satellite, will blast off on board the GSLV from Indian soil at the end of this year, according to the ISRO chairman, although January 2024 is likely.

Other Launches

“There are many more launches of PSLV scheduled,” Somanath said, without going into the details. One of those PSLV launches presumably involves the Aditya-L1 mission.

Aditya-L1 is India’s first space-based mission to study the Sun. It is expected to take off mid-year 2023, either in June or July, with an expected mission life of five years or more.

The multi-wavelength solar observatory in space — to be in a halo orbit around Lagrangian point 1 of the Sun-Earth system, 1.5 million kilometres away — aims to provide continuous coverage of the Sun’s atmosphere in various wavelengths of light. 

“This year, 2023, this is the inaugural launch. And I think that this will set the tune (tone) for the rest of those activities that are going to happen,” the ISRO chief said after the SSLV-D2 success.