Knowledge Nugget | NISAR in focus: Why is this NASA-ISRO mission relevant for UPSC Exam

Why in the news?

The much-awaited launch of NISAR — an earth observation satellite jointly developed by NASA and ISRO — is set to take place on July 30 at 5:40 pm from the country’s only spaceport in Sriharikota, Andhra Pradesh. There have been several delays in the launch of the satellite, with the scheduled launch last year being pushed after technical issues. In this context, let’s know about NISAR and its mission.

Key Takeaways :

1. NISAR, which stands for NASA-ISRO Synthetic Aperture Radar, has been built by space agencies of the US and India under a partnership agreement signed in 2014.

2. It will be launched on the GSLV-F16 and be put in a 734 km sun synchronous orbit — an orbit in which the satellite reaches over a place at the same time each day.

3. It will scan the entire globe every 12 days, proving a series of very detailed images of the Earth’s surface. Weighing 2,392 kg it will be the first satellite ever to observe the Earth in two frequencies — NASA’s L-band and ISRO’s S-band. “Each system’s signal is sensitive to different sizes of features on Earth’s surface, and each specializes in measuring different attributes, such as moisture content, surface roughness, and motion,” according to NASA.

4. Putting two radar systems on a single satellite is a unique engineering feat because the two systems require different sets of hardware, and yet have to function in a complementary fashion without interfering with one another.

The NISAR mission will help researchers get a better understanding of how Earth’s surface changes over time, including in the lead-up to volcanic eruptions like the one pictured, at Mount Redoubt in southern Alaska in April 2009. (Image Credit: JPL NASA)

5. This would mean that the satellite would be able to provide very high-resolution data, in all types of weather conditions, and both during the day and the night. The satellite is powerful enough to capture changes as small as one centimetre in size during its repeated observations over the same terrain.

6. While NISAR won’t be able to predict earthquakes, it will be able to study the dynamic processes happening on Earth’s surface, like retreat of glaciers, movement of sea ice, the path of a storm, changes in vegetation and forest cover, and even the movements during earthquakes and volcanoes. Scientists expect this satellite to provide new insights into our understandings of processes like climate change or natural hazards and better prepare for them.

7. It can also help with practical applications such as tracking the changes in soil moisture or mapping surface water levels.

8. Costing around USD 1.5 billion, it is the most expensive earth observation satellite in the world, with ISRO contributing Rs 469.4 crores for the satellite. The Indian space agency will also incur costs in launching the satellite.

BEYOND THE NUGGET: LUPEX (Lunar Polar Exploration)

1. Chandrayaan-5, also known as LUPEX (Lunar Polar Exploration), is a joint project between ISRO and  Japan Aerospace Exploration Agency (JAXA) to study water and water-ice both on the lunar surface and the subsurface. Weighing 6.5 tonnes, it is proposed to lift off on a Japanese rocket, H3, sometime in 2027-28.

2. Using the rover, JAXA teams plan to trace areas on the Moon with presence of water, sample the nearby soil or regolith by drilling into the surface. The onboard instruments will measure the water content and its quality and perform other in-situ observations.

3. ISRO is developing Chandrayaan-5’s lander whereas JAXA is building the 350-kg rover. There will be seven scientific instruments onboard, some contributed by the European Space Agency (ESA) and NASA. ESA is developing the mass spectrometer and NASA the neutron spectrometers — both are currently in the design phase.

4. The Union Cabinet approved Chandrayaan-5 in March this year, more than a year after India became the first country to achieve a soft landing on the Moon’s south pole with Chandrayaan-3. The proposed Chandrayaan-4 mission will be a return sample mission: samples dug from the Moon will be brought to Earth for ISRO to study the mineral composition of the lunar surface.

5. Spectrometers are specialised scientific instruments that aid in performing in-situ (at the site) experiments requiring calculation of the energy and mass of samples. These experiments help understand the evolution of the composition of hydrogen and other elements.

6. The rover will be designed and programmed by JAXA to travel certain distances on the lunar surface and climb hills up to an inclination of 25 degrees. “The batteries’ charging (of the rover) have been planned in such a way that they will be charged once each before and after sample collection. This is very complex,” said Dai.

7. On the LUPEX mission life, he said: “If everything goes well as planned, then towards the end of the mission, we hope to go to the far side of the Moon. And if possible, extend the mission life by a year.”

Post Read Question

With reference to the NISAR satellite, consider the following statements:

(Sources: NASA-ISRO joint satellite NISAR set for July 30 launch, Chandrayaan-5 mission: India, Japan to enter design phase)

Subscribe to our UPSC newsletter. Stay updated with the latest UPSC articles by joining our Telegram channel – Indian Express UPSC Hub, and follow us on Instagram and X.

🚨 Click Here to read the UPSC Essentials magazine for July 2025. Share your views and suggestions in the comment box or at manas.srivastava@indianexpress.com🚨