New Delhi. Chandrayaan 2, India’s second mission to the Moon which was to land the Vikram rover on the Moon surface on 7th Sep 2019, faced a glitch at the proverbial last minute, just when it was 2.1km above the moon’s surface after successfully manoeuvring gravitational pulls and hazards for a little short of 400,000km.
Just before the planned automated touchdown, Vikram lost communication with the Chandrayaan orbiter, which of course continues to send pictures of the moon’s surface from its high resolution cameras, and was able to track down the lost rover through its thermal imagers.
Over three days of search, it has also located the lander, confirmed that it had a hard landing, was intact but not oriented to restore links with the orbiter, and accordingly the Mission Control.
Perhaps, that means ISRO will have to make another attempt.
ISRO is still analysing what went wrong. It has a 14-day window – that is 14 Earth Days equal to One Lunar Day – to understand what went wrong with Vikram’s automated soft landing programme, and what made it go wrong. Was there a natural surface upheaval, like a storm or a quake? Or whatever!
Communication with the Lander cannot be restored, assuming it has not suffered any damage, till it is oriented to receive signals from the orbiter above. ISRO has a lot of data to analyse, hoping the celestial order does not make its moonquest a farther dream.
Another landing project could take 3 or 4 years.
ISRO, which happens to mark 50 years of its inception, has done well nonetheless, and Prime Minister Narendra Modi, who was present at the Mission Control for the final moments of the Chandrayaan mission, expressed admiration for the ISRO scientists and promised government’s support to realise India’s dreams.
Said ISRO: “Chandrayaan 2 mission was a highly complex mission, which represented a significant technological leap compared to the previous missions of ISRO to explore the unexplored.”
ISRO drew applause from the US NASA and French CNES, which helped Indian space scientists in the early years. Notably, France trained about 20 engineers from IITs and Engineering Colleges in India in space research from the 1960s and they became the foundational pool of talent for ISRO.
France has not gone to the moon but is regarded as capable of doing so. CNES President Jean-Yves Le Gall observed: “In these difficult times, CNES and France stand with ISRO and India. Space is very difficult. India is a great space power. The journey continues.”
NASA, which is a champion for moon missions through its Apollo Shuttle missions and landed astronauts on the moon six times, said in a statement: “Space is hard. We commend ISRO’s attempt to land their Chandrayaan 2 mission on the Moon’s South Pole. You have inspired us with your journey and look forward to future opportunities to explore our solar system together.”
India’s Chandrayaan 1 mission, it may be recalled, had located water molecules on the moon, and that was thanks to Raytheon radar contributed by a US institution. ISRO missions do carry instruments from other countries as available through cooperative support.
India is making a great effort in scientific research, and notably, both the Space and Nuclear programmes are directed and monitored by the Prime Minister’s Office. Mr Modi has been extremely supportive.
Once ISRO lost the contact with the lander, nothing was known about the mission for the next couple of hours. ISRO Chairman K Sivan could be seen in tears but Mr Modi hugged him to express appreciation for the ISRO team and the many successes this great organisation has achieved.
After about 30 hours, Dr Sivan announced that they have received a thermal imagery from the orbiter which is giving indications about the presence of Lander on the surface of the Moon. Two days later, the lander’s status has been confirmed: Intact but disoriented and therefore no connectivity even if it has not suffered any damage.
If, if the lander is intact, there is a remote possibility that it might regain a proper position and reorientation through force of weather storms and then be able to contact the orbiter. That’s a possibility which cannot be ruled out. It would however be a bit premature to reach any definitive conclusion.
If the lander’s position is close to its planned landing site, then it would be a good piece of news, giving hope that at least till the end, the system was possibility working and there could still have been a soft-landing. There are storms and unpredictable natural conditions that could have affected the Vikram lander and set it off course. Even a soft landing though would not mean a safe landing.
The Thermal band is an outstanding tool for measuring the surface temperatures. A thermal imagery recognises the contrast in temperature and such contrast offers a hint about the nature of object.
However, such images are not the photographs offering direct evidence and only the techniques of imagery interpretation could allow to learning more of this image. Such interpretation begins with identification and analyses of few basic elements like location, size/shape, shadow, texture and pattern.
Normally, thermal images are black and white in nature, hence colour as an element for analyses is not available. There are methods (which use some instruments) to judge the height and depth aspects. At present some AI (Artificial intelligence) based techniques are also available. Also, an isolated imagery may not offer a full understanding and for the sake of comparison, multiple sets of imageries are required.
Since the loss of contact with the lander, ISRO is doing its best to know more and re-establish the contact. They are assessing telemetric data, information regarding emissions and signals, mainly during the final minutes.
The information about the descent of the lander craft towards the Moon is available in the form of a trajectory of the last 15 minutes of travel to the Moon. A very visible deviation could be seen around 12th minute when the contact was lost. Otherwise, there is also a slightly visible kink in that trajectory, possibly somewhere around 7th to 9th minute.
ISRO would have to go into every small detail and aspects associated with the last 15 minutes of the lander’s travel, including its attitude and speed.
ISRO has both the technological and scientific ability to do so. In addition, there are Space/Earth telescopes and even possibly few orbiters of other countries which may assist ISRO to know more about the Vikram lander.
India’s Moonquest will not be a lost dream.
