Spirit,free no more

NASA headquarters in Washington,said during a telephone news conference.

In March,the Spirits six wheels broke through a hard crust into sandy material and became stuck.

Spirits right front wheel stopped turning in 2006,and since then,it has generally travelled backward,which makes it easier for it to drag the lame wheel. The rover was moving backward last March when the wheels on the right side broke through the crusty surface into a fluffy,sandlike material. During the next couple of weeks,the right wheels sank,almost buried.

Engineers then spent seven months with test rovers in a sandbox at the laboratory,exploring strategies for getting out of the sand.

In November,the managers decided to have the Spirit retrace its tracks by moving forward. The rover immediately ran into more trouble when the right rear wheel also failed,leaving just the middle wheel on the right side still turning. The progress was minuscule,leading to the decision last week to reverse course again.

The plight of the Spirit has motivated people to send e-mail messages suggesting how to get out. The most common advice is that the Spirit should use its instrument arm,located at the back,to lift and push itself out like a backhoe.

Its kind of a poignant moment for us, said Steven W. Squyres,the missions principal investigator.

Mission managers will focus in the coming weeks on trying to get the rovers solar panels pointed more toward the sun. As the Martian winter approaches,the shorter days will mean less energy,and the rover will most likely exhaust its batteries. The rover is programmed to put itself into a deep sleep,and it was designed to survive the frigid cold.

She was designed to go through this,but again Ill caution this was for a brand new rover, said John Callas,the project manager.

Even if its roving days are behind it,the Spirits work may not be over. Next month,NASA will review the Mars missions in preparing its budget and plans for the fiscal year that begins in October. The rover team has prepared a proposal for using the Spirit as a stationary science station

The Spirit could also continue to take weather measurements,and its accelerometers could act as seismometers,listening for Mars quakes.

The beginning of the Martian winter is in May,and the NASA officials are hoping that the Spirit can resume its science activities in August or September,conducting radio and atmospheric studies that were not possible when it was moving. Precise radio measurements could pin down wobbles in Mars axis of rotation,and that could tell whether the center of the planet is liquid or solid.