ISRO aims high

Dinesh C Sharma

THE Indian space programme reached a landmark in 2023 with the successful landing of an Indian spacecraft on the lunar surface. This placed the Indian Space Research Organisation (ISRO) among the handful of space agencies globally that have achieved this feat. The lunar landing was followed by another high-profile mission — Aditya L1 — to study the sun in September 2023. It was a busy year for Indian space scientists with several other missions, including the first demonstration flight of the Crew Escape System test vehicle for the human space mission. Another big-ticket announcement was the place to build an Indian space station by 2035.

Aditya L1 mission

The New Year is all set to begin with a bang on the space front. The Aditya L1 satellite, which was launched in September 2023, is scheduled to reach its destination point on January 6 after having traversed 15 lakh kilometres. Since its launch, the solar observatory has been subject to several complex manoeuvres in its journey towards the sun. The final manoeuvre will be to inject the satellite into the L1 or Lagrange point, from where it will keep observing the sun for the next five years.

Any space object placed in a Lagrange point remains in that position as the gravitational forces of the sun and the earth produce enhanced regions of attraction and repulsion. There are five such points and Aditya will be placed at the L1 point, which affords an uninterrupted view of the sun. In December, the scientific instruments onboard Aditya L1 had already started taking pictures of the sun. The full-disk images of the sun’s photosphere and chromospheres captured by the Solar Ultraviolet Imaging Telescope have been described as unprecedented.

The (NISAR) mission will be a powerful demonstration of the capability of the radar as a science tool and help us study earth’s dynamic land and ice surfaces in greater detail than ever before. S Somanath, Chairman, ISRO

NISAR will deliver unprecedented data on how climate change is impacting our planet. Bill Nelson, NASA Administrator

Polarimeter satellite

Another scientific mission slated for launch in January 2024 is the XPoSator X-ray Polarimeter Satellite — the first dedicated mission to study the dynamics of bright astronomical X-ray sources. It comes in the series of astronomical missions of ISRO like Astrosat and will carry two scientific payloads in a low earth orbit. These instruments are designed to study the degree and angle of polarisation in specific frequencies and provide spectroscopic information about celestial objects.

Astronomical bodies like black holes, neutron stars, active galactic nuclei and pulsar wind nebulae constantly undergo complex physical processes, and emissions from such sources are of great interest to astronomers. The X-rays emitted are polarised and a study of polarisation serves as a diagnostic tool for the radiation mechanism and geometry of celestial sources. For instance, it can give an idea about the mass and spin of accreting black holes.

NISAR satellite

Perhaps the most significant mission of ISRO during 2024 will be that of the NASA-ISRO Synthetic Aperture Radar or NISAR satellite. It is a joint venture between the UR Rao Space Centre of ISRO and Jet Propulsion Laboratory of NASA for which scientists have been developing instruments for several years.

The satellite will map the entire globe in 12 days, providing spatially and temporally consistent data for understanding changes in the ecosystems, ice mass, vegetation biomass, sea-level rise, groundwater as well as natural hazards like earthquakes, tsunamis, volcanoes and landslides. As the name suggests, the satellite is equipped with Synthetic Aperture Radar in two bands (L and S) to yield high-resolution data across large swathes. The data will be available for both the countries and for the scientific community as well.

Gaganyaan project

The space agency is planning several significant programmes over the next year for its most ambitious project — the Gaganyaan or the human space flight. The project envisages a demonstration of human spaceflight capability by launching a crew of three members to an orbit of 400 km for a three-day mission and bringing them back safely to earth by landing in Indian sea waters. For this, it would need a well-proven and reliable heavy lift launcher, an orbital module that will be orbiting the earth, comprising a crew module and a service module (SM), and astronaut training facilities for micro-gravity familiarisation, recovery and survival training, flight procedures, etc.

The elaborate project involves some 20 major tests, including the launch of three uncrewed missions of the Human Rated Launch Vehicle. The first demonstration flight of the Crew Escape System took place in 2023. The crew module tested in October was an unpressurised version but had the overall size and mass of the actual Gaganyaan module. The one in which astronauts will travel will be pressurised and have earth-like atmospheric conditions. One or two uncrewed missions are expected during 2024 along with other tests.

Indian astronaut for ISS

While the launch of an Indian human space mission will have to wait for all the necessary tests over the next two years, an Indian astronaut may travel to the International Space Station (ISS) in 2024, as announced during the last visit of Prime Minister Narendra Modi to the US.

As per this plan, NASA is identifying an opportunity to accommodate an Indian astronaut in the flights to ISS. When this happens, it will be the second time an Indian citizen will travel to space. The first was Rakesh Sharma, who did so as part of the India-USSR space mission four decades ago.

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