Spirit takes root on Mars

Having spent 6 years on the red planet, NASA’s rover appears to be stuck for good, but is to continue its scientific work.

 

360° panoramic colour view of Spirit’s current place of residence. NASA’s rover has now to remain stationary and observe Mars from this area dubbed Troy by the mission team. Credit: NASA/JPL-Caltech/Cornell University

The Spirit rover successfully landed in the middle of the Gusev crater on Mars on 4 January 2004. Despite currently being bogged down in sand, the vehicle’s mission has long been a great success and it could continue but with different objectives.

The route to the Columbia hills
Spirit is part of a double motorised exploration of Mars. Just a few days later, an identical rover dubbed Opportunity landed in another region. But although this one very quickly discovered, actually on its landing site, signs that water was once present in the red planet’s distant past, Spirit did not find anything comparable and surveyed a desert landscape scattered with rocks of volcanic origin. The scientists admitted their disappointment as they thought that the Gusev crater (170 km wide and the result of a meteorite impact) could previously have been filled with water... It was then decided to direct the rover towards the Columbia hills, thus named to pay homage to the 7 astronauts that died in the accident of NASA’s space shuttle of the same name in 2003. The long journey proved worthwhile as Spirit, in turn, ended up discovering signs linked to water.

This map shows the route taken by Spirit since it arrived on Mars. The references are in “sol”. One “sol” is one Martian day which, lasting an average of 24 hours and 39 minutes, is a little longer than an Earth day. The Martian year lasts 686.98 days and the seasons there are therefore twice as long as those on our planet. In 6 years, and before becoming bogged down, Spirit travelled 7,730.24 m. Credit: NASA/JPL/Cornell/MRO-HiRISE/Museum of National History and Science

Stationary but useful
A scientific success, the saga of these two rovers has also exceeded the wildest hopes from a technical point of view. Designed and “guaranteed” to operate for 90 days, the twins are still operational today after having spent 6 years in the harsh Martian environment (extreme cold, sand storms, etc.). Unfortunately, ten months ago Spirit fell into a dreadful trap: its wheels ran over a crusty surface and became embedded in the soft sand underneath. NASA’s JPL (Jet Propulsion Laboratory) has reconstituted the terrain encountered on Earth, complete with a replica of the rover in order to test the most effective manoeuvres and to try and deduce an exit strategy; all in vain. The American Space Agency has therefore officially announced the end of the rescue operations. Spirit is now to become a stationary research platform.

Ground teams have scrupulously reconstituted the terrain encountered on Mars in order to get Spirit out of its trap. With a replica of the rover, engineers have tested numerous exit strategies, all to no avail. Crédit : NASA

It is to take numerous measurements linked to the Martian environment that will be linked not only to the effect of the winds on the ground but also the composition of the atmosphere. In the long-term, thanks to the radio signals that it sends out, the “rooted” rover could even make it possible to detect minute variations in the rotation of Mars and therefore to know whether this planet still has a liquid metal core or whether it has solidified, sign of geological death.

For just a few more Watts...
However, Spirit’s new mission is far from being a sure thing! In actual fact, its solar array are poorly angled and with winter approaching in this region, the production of electricity will quickly become insufficient in the face of the cold to ensure the survival of the onboard electronics.

Spirit’s two front wheels. Held prisoner in the sand, the one on the left-hand side is only partially visible. Credit: NASA/JPL-Caltech

Therefore, Spirit’s “drivers” are shortly going to attempt several small manoeuvres so as to create sufficient tilt. Just a few degrees could be enough to better angle the photovoltaic cells which would mean additional precious Watts. Take heart Spirit!

Enjoy Space portfolio on the Spirit and Opportunity rovers

Published on 27 January 2010