‘India is on the moon!’ Successful landing for Chandrayaan-3

Update: Success! The world is celebrating with India, as India has achieved its first soft landing on the moon. Chandrayaan-3 landed on the moon near the south pole around 7:30 a.m. CDT on August 23, 2023. In addition, the team deployed the rover ramp. Watch the livestream replay in the player below and watch a video that shows the rover reaching the moon’s surface.

Chandrayaan-3 Mission:
?What's new here?

Pragyan rover roams around Shiv Shakti Point in pursuit of lunar secrets at the South Pole ?! pic.twitter.com/1g5gQsgrjM

— ISRO (@isro) August 26, 2023

Chandrayaan-3 Mission:
The image captured by the
Landing Imager Camera
after the landing.

It shows a portion of Chandrayaan-3's landing site. Seen also is a leg and its accompanying shadow.

Chandrayaan-3 chose a relatively flat region on the lunar surface ?… pic.twitter.com/xi7RVz5UvW

— ISRO (@isro) August 23, 2023

Chandrayaan-3’s Pragyan Rover includes an indent of the national emblem of India and the logo of ISRO on its two rear wheels.

As the Pragyan Rover is deployed on the Moon’s South Pole, the wheels will leave an impression of these symbols in the lunar soil for billions of years. pic.twitter.com/7IhqX149aQ

— Toby Li (@tobyliiiiiiiiii) August 23, 2023

Watch the livestream of ISRO’s landing near the south pole of the moon at the feed above.

Ian Whittaker, Nottingham Trent University

Moon landing for India includes a rover

On Wednesday, August 23, the Indian Space Research Organisation (ISRO) mission Chandrayaan-3 deployed its lander and rover to the surface of the moon. As the name suggests, this is the third mission in a program of Indian lunar exploration. Various problems affected the previous two Chandrayaan satellites, so officials at the Indian space agency hope for a fully successful mission this time.

So what will Chandrayaan-3 do? We have some nice images of the lunar surface from the lander module camera, which shows the successful separation from its propulsion module. That’s the part that stays in lunar orbit. But the main task for the lander and rover is to show that the ISRO can successfully perform a gentle landing on the moon.

What’s on the moon lander?

The lander unit contains four main scientific instruments, including thermal and atmospheric instruments and a laser retroreflector array. These reflectors are used to measure the distance to the moon from the Earth to a high degree of accuracy.

Essentially, a high-power laser is fired toward the moon. Then scientists measure the time taken for the light pulse to reach the moon and reflect back to Earth. Knowing the speed of light, the time it takes (roughly 2.5 seconds there and back) gives us a distance. The lander is also able to measure moonquakes, weak seismic activity that occurs on a monthly basis.

Scientists can use the speed that the waves travel across the moon to work out its density. Researchers hope to be able to calculate more accurate values for the depth of the lunar crust (its outermost layer).

The rover also contains scientific instrument packages. Its main focus is on identifying the composition of the lunar surface through X-ray spectrometry.

Chandrayaan-1

The first mission in the program, Chandrayaan-1, launched in 2008. Both subsequent missions share a technological heritage with this original spacecraft. It consisted of a satellite and a probe designed to hit the surface at high speed. For the first year of planned operation, the satellite provided some groundbreaking results, including mapping the moon in a range of wavelengths. It was looking to determine the composition of the lunar surface, focusing on elements such as calcium, magnesium and iron.

Arguably the most successful result, though, was in conjunction with the onboard moon impact probe. This was a planetary penetrator, which is a small number of instruments packed into aluminum for protection and then fired at the surface. The plan was to prepare for a later lunar rover. But the probe also allowed the orbiter to detect liquid water on the lunar surface. Scientists had long thought that water existed as ice, hidden away in shadowed craters at the moon’s poles.

The high speed impact of the penetrator threw large numbers of particles from the lunar surface into the atmosphere. By analyzing how sunlight is scattered from these particles, their chemical composition can be determined.

The Chandrayaan-1 mission was classed as a success, despite the fact that only half way through its planned mission timeline, engineers lost communication with it.

Chandrayaan-2

The intention with the second Chandrayaan mission was to take a lander and rover to the lunar surface. The orbiter reached the moon in 2019 and dropped the combined Vikram lander and Pragyan rover to the surface 2 1/2 weeks later.

Unfortunately, in a similar incident to that seen with Chandrayaan-1, engineers lost communication with it. The combined mass of almost 1.6 tons – roughly the weight of a small car – crashed into the surface.

Third time’s the charm?

It looks like it! This third mission escaped the apparent curse that has plagued the previous two. So far, things are looking very hopeful. The mission launched on July 14, 2023, and successfully landed on the moon on August 23, 2023.

The deployment of the lander and rover was the true test. It means that India has become the fourth country to have had a working rover on the lunar surface behind the Soviet Union, U.S., and China. This will massively improve its reputation for scientific space launches. Also, it potentially gives the agency more leverage for funding future mission planning as well.

An important part of this mission is also the cost of US$75 million (£59 million). That’s an exceptionally low budget for a research mission leaving the Earth. It is comparable to the cost of a SpaceX Falcon 9 launch. It is worth comparing this cost to the recent NASA Artemis mission, which has future planned costs per launch of US$800 million (£629 million). And that doesn’t include the $13.1 billion (£10.3 billion) development costs over the last 20 years.

The Chandrayaan-2 orbiter is still working, in orbit around the moon. This means there are options for Chandrayaan-3 in the event that anything should go wrong, as the other satellite can act as a back-up communications platform, reducing the chance of a mission failure.

The meaning of success

The results from both the lander and rover will help scientists scout future lunar landing sites and potential lunar base locations. A knowledge of the landing site is essential for any larger structures, as there is a lot less margin for error due to the higher costs. Being able to build structures out of local resources such as lunarcrete – using lunar soil as a cement-like building material – is a great way to reduce the mass that needs to be launched from Earth. But it also requires the right material located nearby.

Personally, I was hoping for Chandrayaan-3’s success, as it seems more and more that private companies are competing to carry out space missions and exploration. With the primary end goal being a commercial one – either tourism or resource collection – it is likely that that scientific discovery will be left out, reduced to an afterthought, or even hindered. So every success by a space agency means more free-to-use data for both the scientific community and the public.

Ian Whittaker, Senior Lecturer in Physics, Nottingham Trent University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: India’s Chandrayaan-3 moon mission successfully landed a rover and lander on the moon on August 23, 2023. You can watch the livestream of the landing here.

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