27 January 2010
The US space agency (Nasa) has decided to stop trying to free one of its robots from soft sand on the planet Mars.
The Spirit Mars rover has been stuck since May 2009.
Click to hear the report:
Dug deep into the soil and with its wheels spinning, Spirit has had to accept the inevitable - it's never going to move again. In its six years on the planet, this robotic geologist has taken thousands of images and found evidence in the rocks of a wetter, warmer past in Mars' history. Its mission will now have to change. As a static station, it can still study the planet's atmosphere and deep interior. The priority currently is to position its solar panels to get as much energy from the Sun to keep it alive through the coming winter.
Even so, Nasa expects Spirit to get so low on power that it'll go into hibernation, cutting communications with Earth for perhaps six months.
Whatever the future holds for Spirit, its mission has been an outstanding success. When it landed on the Red Planet in January 2004, no-one was really sure how long it would continue working in what is a cold and dusty environment. Three months was one initial goal.
In the event, it just kept on rolling. And its twin robot, Opportunity, which landed a few weeks after Spirit in a different part of Mars, continues to rove freely to this day.
Nasa has spent more than $900 million on the project but shows no sign of giving up on these tenacious robots. The rovers are, though, experiencing gradual wear and tear. Even before Spirit got trapped, one of its wheels had failed. And Nasa says it's just a matter of time before both robots break down completely.
Jonathan Amos, BBC Science Correspondent
Click to hear the vocabulary:
turning around and around but not able to move forwards or backwards
- to accept the inevitable
to agree that there is nothing that can be done to change something
- robotic geologist
machine used to study the structure of a planet and its rocks
- go into hibernation
switch to a power-saving mode and use as little energy as possible until it is able to 'wake-up' again when there is more energy available
- initial goal
the first plan which would have been thought a success
- to rove freely
to travel easily
determined and hard-working
- wear and tear
the expected damage to something caused by using it repeatedly over a period of time