NASA finds India’s Vikram moon lander crash site, with amateur’s help

Since India lost contact with the spacecraft in September, the precise location of its crash has been a mystery.

NASA has found pieces of Vikram, a small spacecraft that India attempted to land on the moon in September. They did it with the help of an engineer from India who scoured the lunar surface in his spare time.

Vikram was part of India’s Chandrayaan-2 mission to the moon, which launched in July. If the spacecraft had reached the surface in one piece on Sept. 7, India would have been only the fourth country to successfully put a lander on the moon.

But less than two miles above the surface, Vikram veered from the planned descent trajectory and fell out of radio contact.

India’s space agency said the next day that it had located the lander. But it never published any images of the hard landing site taken by the mission’s accompanying orbiter, which remains in operation and is carrying out a scientific mission that will last for years.

A NASA spacecraft, the Lunar Reconnaissance Orbiter, has passed over the mission’s intended landing site, on a high plain near the south pole, several times since September. But initial analyses of the images did not reveal an obvious impact scar comparable to the Beresheet lander launched by Israel this year, which crashed in April. NASA scientists noted that the spacecraft might have been hidden in the shadows.

A lot of people were looking, including Shanmuga Subramanian, an Indian computer programmer and mechanical engineer.

“The crash landing of Vikram rekindled an interest in the moon not only for me and others also,” he wrote in an email. “I think even if Vikram had landed and sent some images, we would have never had such interest. For the first few days I was scanning the images randomly and there were lot of false positives.”

After reviewing the last known velocity and position of Vikram, Mr. Shanmuga shifted where he was looking. He noticed a white speck on the lunar surface that was about two-thirds of a mile from where Vikram was supposed to have set down.

That speck was not visible in an earlier image. He wondered if the crash might have buried the lander in the lunar soil.

@NASA @LRO_NASA @isro
This might be Vikram lander's crash site (Lat:-70.8552 Lon:21.71233 ) & the ejecta that was thrown out of it might have landed over here https://t.co/8uKZv7oXQa (The one on the left side was taken on July 16th & one on the right side was from Sept 17) pic.twitter.com/WNKOUy2mg1

— Shan (@Ramanean) 17 November 2019

Mr. Shanmuga reported what he had found to NASA and scientists working with the Lunar Reconnaissance Orbiter’s camera, who confirmed his finding and scoured the surrounding area. Comparing images taken before Vikram’s landing attempt and those taken on Nov. 11, they were able to identify the impact point about 2,500 feet to the southeast of the planned touchdown site, and a spray of debris emanating outward.

An image generated from the ratio of the brightness in the before and after images more clearly shows how the impact of Vikram disturbed the lunar soil.  Credit... NASA/Goddard/Arizona State University

The pieces of debris were not much bigger than the minimum of what the camera could make out. The resolution of the camera was about 1.3 meters per pixel; the three largest pieces of debris were about two pixels by two pixels in size and cast a one-pixel shadow, NASA said.

@NASA has credited me for finding Vikram Lander on Moon's surface#VikramLander #Chandrayaan2@timesofindia @TimesNow @NDTV pic.twitter.com/2LLWq5UFq9

— Shan (@Ramanean) 2 December 2019

(Source: NYT) 

Chennai engineer helps NASA locate Vikram lander

NASA's Lunar Reconnaissance Orbiter mission of Goddard Space Flight Centre has credited Shanmuga Subramanian, a mechanical engineer in India, for the discovery in an official email.

A Chennai engineer has helped American space agency NASA to find pieces of Vikram lander on moon's surface. 

NASA's Lunar Reconnaissance Orbiter (LROC) mission of Goddard Space Flight Centre has credited Shanmuga Subramanian, a mechanical engineer in India, for the discovery in an official email.

"Thank you for informing us of your discovery of debris from the Vikram lander. The LROC team confirmed that the location does exhibit changes in images taken before and after the date of the landing. Using this information the LROC team did additional searches in this area and located the site of the primary impact as well as other debris around the impact location and has announced the sighting on the NASA and ASU pages where you have been given credit for you observation," John Keller, Deputy Project Scientist, LROC, said. 

Vikram was part of India’s Chandrayaan-2 mission to the moon, which launched in July.

If the spacecraft had reached the surface in one piece on September 7, India would have been only the fourth country to successfully put a lander on the moon.  

Subramanian had contacted NASA in October, but it took time for the American space agency to be certain of its interpretation of the observation as well as making sure that all the stakeholders had an opportunity to comment before they would announce the results. 

Subramanian told Express that he was happy that his work got the due recognition. 

(Source: TNIE)

'15 minutes of terror': What ISRO learns from Chandrayaan-2 mission

Ever since the Indian Space Research Organization (ISRO) announced the launch of Chandrayaan-2, its most ambitious mission till date, it had put just one caveat -- the crucial powered descent on the moon, which it was attempting for the first time.

India had been to the moon before with the successful launch of Chandrayaan-1 in 2008, which gave the world evidence of water molecules on the lunar surface. So, it was evident that the team was confident of accomplishing the feat again.

A video played on a giant screen showing the Chandrayaan 2 tracking in a media enclosure at ISRO. Photo: PTI (PTI)

The crucial manoeuvres required to place a spacecraft into the desired moon orbit , the trans-lunar injection and lunar orbit insertion had gone precisely as planned for Chandrayaan-2. The inclination to the lunar surface was closer to precision. Lander Vikram had successfully separated from Orbiter and de-orbited to an elliptical orbit of 35 X 100 kms, from where it began the powered descent on Saturday.

But it was during the last phase of the mission which involved executing a soft landing on the moon - new to ISRO, that the results did not go as planned. In the days leading to the final event, ISRO chairman K Sivan had described the moments as "15 minutes of terror" when Lander Vikram would entirely be on its own, with no ground control to guide it.

On Saturday, during those 15 minutes the enthusiasm of the entire team turned into despair. Lander Vikram lost all communication with the ground station during the last two minutes when it was just 2.1 km above the lunar surface.

The power descent was indeed one of the most complex exercises that ISRO had ever undertaken, which involved reducing the velocity of the Lander from 1.6 km/second to zero in a controlled manner. The agency made use of a new technology-- the five thrusters which would be fired in stages to bring down its velocity.

All simulations, testing and verification were done several times on earth. But there were uncertainties involved in executing it on the moon. The moon has no atmosphere and the gravity is one-sixth of that of earth, and actions have to be performed accordingly. There was no muscle memory of landing on the moon.

A similar attempt by Israel in April could not achieve success. But, ISRO tried to learn from that and decided to strengthen the sensor characterisation of Lander so it does not get impacted due to any human error. It also accounted for any communication delay, because the Lander was designed to be autonomous and take decisions on its own.

But, it could not control the velocity during the last two minutes and could not achieve a soft landing on the moon. The orbiter, however, continues to revolve around the moon at an altitude of 100 km above the surface and would continue the Chandrayaan-2's exploration.

(Source: Live Mint)

ISRO's Vikram Lander drops short by 2.1 km, but Orbiter keeps Chandrayaan2 alive

The Vikram Lander from Chandrayaan 2’s orbiter was meant to land on the lunar surface on Sept 7 but telecommunication link was lost.

Like everything Indian, there was plenty of drama and high emotion at the scheduled touchdown of Chandrayaan2's Vikram Lander on the Moon's surface on Sept 7 at 1:52 am IST.

Just 2.1 km short of landing, all connections with the Vikram Lander was lost. The Lander, which had detached from Chandrayaan 2’s Orbiter on September 2, had been manoeuvring around the Moon for nearly five days.

As ISRO Chairman Dr K Sivan said, everything was according to plan and just short of 2.1 km, communication was lost. He added that ISRO is analysing the data sent by Vikram Lander.

In an official statement released at 3 am, ISRO said, "Vikram Lander descent was as planned and normal performance was observed up to an altitude of 2.1 km. Subsequently, communication from Lander to the ground stations was lost. Data is being analyzed."

This is Mission Control Centre. #VikramLander descent was as planned and normal performance was observed up to an altitude of 2.1 km. Subsequently, communication from Lander to the ground stations was lost. Data is being analyzed.#ISRO

— ISRO (@isro) 6 September 2019

The mission is being constantly monitored by the ISRO Telemetry Tracking and Command Center (ISTRAC) at Bengaluru.

Prime Minister Narendra Modi, who was at the ISTRAC, encouraged the scientists for the hard work and said he had full faith in them. He said, "Let's not lose hope. You (ISRO scientists) have done a lot for mankind and I am with you all the way."

PM Modi also met school children, who had come to witness the historic landing. To a question posed by a student on how can they keep themselves motivated in life, PM Modi said do not carry your failures on your shoulder. Keep moving ahead.

Which is what the ISRO scientists will be doing now. All is not lost. The Orbiter, which is equipped with instruments to carry out various tests, is still on course.

The sequence of soft landing of Vikram lander on the lunar surface (Image: ISRO)

What should have happened according to plan had Vikram landed?
With two engines on at an altitude of 400 metres, the Vikram Lander should have descended in a parabolic manner. During its final stage, Vikram Lander would have created an opposite force to make sure it lands softly on the lunar surface and is also equipped with touchdown sensors at its feet.

Later, it would have started its operation of the deployment of payloads, which is touted as a critical operation. As per ISRO, the Vikram Lander was carrying CHASTE (Chandra’s Surface Thermo-physical Experiment), RAMBHA (Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere) and ILSA (Instrument for Lunar Seismic Activity).

After the deployment of specific payloads, the six-wheeled Pragyan Rover would have started rolling out on the lunar surface at 5:30 am. Prior to which its solar panel would have powered its battery as it descended, and it would have used its NAV camera to scan its surrounding.

Once the scanning was completed, the data was planned to be sent to Earth via Vikram. This scan would have then processed at mission control for planning the path for Pragyan to move ahead.

In case of any obstacle, Pragyan would have used its Rocker Bogie mechanism to overcome it. It was equipped with a movement range of 50 mm upward and downward. Also, mission control would have instructed Pragyan to stop and determine elemental composition of lunar rocks soil using the APXS (Alpha Particle X-ray Spectrometer) payload.

For understanding the lunar surface, Pragyan was meant to engage its LIBS (Laser Induced Breakdown Spectrometer) payload to derive the elemental composition of the lunar surface.

However, all is not lost. Watch this space for updates on Vikram Lander's fate and the next steps by ISRO.

(Source: YS)