Nasa engineers will on Monday initiate a manoeuvre that is their least favourite activity in space: they will attempt to land a robot spaceship on Mars.
In this case they will attempt to set down their probe, InSight, gently on to an area known as Elysium Planitia where it is intended to analyse seismic activity on the red planet.
More probes have been sent to Mars than any other planet in the solar system but more than half of these missions have ended in failure, with the final stages, involving landing gently on the Martian surface, proving to be particularly dangerous and unsuccessful.
The thin atmosphere on Mars – just 1% of Earth’s – means there is little friction to slow down a spacecraft, and that has played a key role in past failures. Hence the nervousness of Nasa engineers who are directing their $800m InSight craft after a 300 million-mile journey at a tiny target zone in the planet’s atmosphere measuring a mere 15 miles by 6 miles.
If InSight passes through this keyhole precisely then it ought to land in the middle of the Elysium Planitia, though it will still need a heat-resistant capsule, a parachute and rockets to cut its velocity from 12,000mph to 5mph and ensure it arrives softly and safely after a seven-minute descent.
The most recent attempt to land on Mars was made two years ago by a European probe, which crashed on the planet’s surface. However, Nasa remains confident of success.
It is hoped InSight – which stands for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport – will help scientists understand the early evolution of Mars and other planets in the solar system, including the Earth, using instruments to probe deep beneath the planet’s surface to measure temperatures and seismic activity.
