Water mission crash lands

RECENTLY we have had yet another reminder that space exploration is an activity that is close to the limit of our current technological abilities.

Certainly we are getting much better at it, but there is still the occasional failure. Last week, India lost contact with its Vikram lander as it was attempting to soft land on the Moon.

The mission had gone well up to that point, but sadly, contact was lost not long before the landing itself near the end of a four-day descent from the main orbiting craft called Chandrayaan-2. The orbiter is still doing well and will continue to orbit the Moon and return images and measurements, but it is likely that Vikram has crashlanded on the lunar surface.

If the soft landing had succeeded, Vikram would have set a record for the most distant landing from the lunar equator. It was aiming for a point at a lunar latitude of 71 degrees south, near the ‘top’ of the Moon as seen from our southern-hemisphere location.

The polar regions of the Moon are of special interest, as it has been found that water exists there. It is not liquid water, but water ice. Evidence for this has been gathered by several spacecraft, most notably by instruments aboard India’s predecessor to the current mission, called Chandrayaan-1, in 2009.

Chandrayaan-1 did not carry a craft to attempt a soft landing, but it did deliberately send an impactor to the polar region of the lunar surface, to disturb lunar material as part of the search for water. Effectively, especially as a result of the Chandrayaan-1 results, it can be stated that there is indeed water ice on the Moon.

Vikram, the lander sent to the surface from Chandrayaan-2, carried a rover called Pragyan. The intention of these craft was to carry out a direct search for water ice over a period of about two weeks until the Sun set over the landing site. The two-week nights on the Moon are very cold indeed, and mission controllers knew that the chances of the two craft surviving over that period were quite low. The date of the landing therefore coincided with “early morning”.

It is known that the lander moved off course not long before touchdown, and the crash site has been identified using thermal imaging. Attempts are being made to resume contact, but that is very unlikely.

There have, of course, been many successful landings on the Moon, the most famous being the crewed landings by the United States between 1969 and 1972. In general, we have done very well with lunar landings, but there have been other occasional failures, too. Earlier this year, an Israeli attempt failed when its little Beresheet lander crash-landed after an on-board gyroscope error.

There must surely be many disappointed scientists in India, and around the world, as there was much anticipation that Vikram would land amongst some detectable lunar ice.

Someday, humans may land in the Moon’s polar regions and make use of this water. It would have been great, however, to get images and data from this part of the Moon.

For now, though, hats off to India for a wonderful attempt.