Space science missions ISRO will launch in the near future

India's nascent space science program to get a much needed boost.

GSLV Mk II rocket transporter. Credit: ISRO

The Indian Space Research Organization (ISRO) is planning several space science missions by 2025, including its first Sun observer and Venus orbiter.

Chandrayaan 3, India’s Moon landing reattempt

An artist’s impression of Chandrayaan 2 Vikram lander deploying the Pragyan rover on the lunar surface. Credit: ISRO

ISRO launched the ambitious Chandrayaan 2 mission in July 2019 with the hope of becoming the world’s fourth country to land a spacecraft on the Moon. The lander unfortunately crashed on the lunar surface on September 7, 2019, taking the rover onboard along with it. However, the Chandrayaan 2 orbiter continues to go around the Moon, and is expected to provide the highest resolution Moon maps to date.

ISRO is now building Chandrayaan 3, which is essentially a repeat of the Chandrayaan 2’s surface mission. In a talk at UPES University, India on December 1, 2020, the agency’s Scientific Secretary R. Umamaheswaran said Chandrayaan 3 will launch in late 2021 or early 2022. The landing site and scientific objectives are expected to be the same as Chandrayaan 2’s lander and rover. The lander will carry, among other experiments, a thermal probe and a seismometer to study the Moon’s interior, and the rover will carry a pair of spectrometers to determine what the ancient lunar crust was made of.

India’s first solar observatory

Launching in late 2021 onboard a PSLV-XL rocket, per ISRO’s Scientific Secretary R. Umamaheswaran, Aditya-L1 will study the Sun’s surface and atmosphere with its seven instruments. It’ll be placed at the first Lagrangian point (L1) between the Sun and Earth, where the gravitational pull of these two bodies roughly cancel out.

The L1 point is not a point as much as a small region in space, host to multiple solar science missions in the past, such as SOHO, ACE, WIND and DSCOVR. Like those, Aditya-L1 will observe the Sun uninterrupted from this vantage point. The spacecraft will have a unique ability to observe the Sun in multiple wavelengths while also measuring the solar magnetic field and the solar wind radiation using its in-situ instruments.

In 2018, NASA launched the Parker Solar Probe on a mission to go right into the Sun’s atmosphere to unravel its mysteries. ESA launched the Solar Orbiter in 2019 on a similar mission. Aditya-L1 will study the Sun from much further away but its global views will allow for its observations to complement data from the NASA and ESA probes and place them in context.

The hope for scientists globally with these solar missions is to explain why the Sun’s corona is hotter than its surface by several million degrees, a major unsolved problem in solar physics.

Specialized X-ray telescope

India’s first space telescope, Astrosat, was designed to observe high energy cosmic objects in multiple wavelengths. The country’s second space telescope, X-ray Polarimetry Satellite (XPoSat), will be smaller and specialized. Launching on a PSLV rocket to Earth orbit in late 2021 or more likely in 2022, XPoSat will study the polarization of X-rays emitted by cosmic objects using a polarimeter built by the Raman Research Institute. How radiation is polarized gives away the nature of its source, including the strength and distribution of its magnetic field.

To this day, the Crab Nebula remains the only X-ray source for which scientists have measured the polarization. XPoSat is expected to provide the same information about the 50 brightest known sources in the universe, including pulsars, X-ray binary stars and gigantic-black-hole-hosting galactic cores.

Collaboration with NASA on a radar-imaging satellite

The NASA-ISRO Synthetic Aperture Radar (NISAR) satellite will be the first satellite with a dual-frequency radar imaging system. At $1.5 billion, it’s among the most expensive Earth-observation satellites ever built. Following its planned launch onboard a GSLV Mk II rocket in 2022, it will be placed in a Sun-synchronous orbit so that its solar panels can provide constant power.

An artist’s impression of the NASA-ISRO Synthetic Aperture Radar. Credit: NASA

NISAR’s dual-frequency radar imaging system will reveal ongoing changes in Earth’s crust, polar ice, climatic processes, biomass, etc., at a high resolution of 3 to 50 meters per pixel, at a rapid bi-weekly pace, globally. The satellite will also be used for disaster management, whereby its data will be available only a few hours after observations. ISRO and NASA have said that all science data from the mission will be in the public domain.

A Venus orbiter in the making

In 2018, ISRO called for instrument proposals for a Venus orbiter mission, Shukrayaan. Originally scheduled for a mid-2023 launch, ISRO is now targeting a December 2024 launch. The primary scientific objectives of Shukrayaan include studies of Venus’ surface and subsurface, its atmospheric chemistry and solar wind interactions with the planet. This is a refreshing mission because an initial interest in exploring the planet during the 1960s to 1980s quickly faded after Mars started getting all the attention.

Venus needs to be explored not just because it hosted water for at least 2 billion years, longer than Mars, but also to understand how Earth-like planets change over time, and what makes Earth a haven for life. Right now, there is only one spacecraft at Venus, the Japanese orbiter Akatsuki, compared to eight at Mars and three more on their way. So ISRO sending a mission to Venus should be refreshing for the global planetary science community.

Shukrayaan will study Venus for over four years from a polar orbit of 200 x 600 kilometers, allowing for global mapping. It will have a payload capacity of about 100 kilograms. In addition to several Indian instruments, ISRO will also be carrying a few international ones. One of them is the French Space Agency’s VIRAL instrument (Venus Infrared Atmospheric Gases Linker) co-developed with the Russian space agency. Foreign collaboration is great, as attested by Chandrayaan 1’s co-discovery of water on the Moon with NASA.


Other missions in ISRO’s pipeline could include a successor to the Mars Orbiter Mission with a previously stated 2024 launch but ISRO has been mum about the mission status since over a year. ISRO also has plans for launching an Astrosat successor but details are unclear at the moment about it too.

Given ISRO’s fairly nascent space science program, the boost to such missions is a welcome trajectory for India’s space exploration endeavors. Here’s hoping that India goes all in on this trend and makes deep space exploration a prioritized national goal just like it has done to launch astronauts.

This post was made possible thanks to Arun Raghavan supporting me on Patreon.

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