14 DAY TRIAL // Three years ago, on the 3rd of January 2004, Spirit rover (photo) parachuted down to Mars's Gusev Crater.
Its twin, Opportunity, landed on the other side of the planet 21 days later.
Spirit is celebrating its anniversary on the Martian surface weathering a dust storm. Early last week, its instruments detected hazy conditions due to a large dust storm to the south. As the storms block a great part of the sunlight from reaching the planet's surface, they are harmful for the rovers, which rely on solar power to get electricity.
So on Thursday, NASA Earth controllers stopped Spirit taking scientific measurements of an volcanic rock named Esperanza and moved it to a slope tilted 7.4? to the north to increase the amount of sunlight caught by the rover. "We had to boogie on out of Esperanza," says Ray Arvidson, deputy principal investigator for the rovers' science instruments at Washington University in St Louis, US.
At one point, its solar arrays failed the energy production to only 267 watt-hours daily, very close to the alert value of 250. On the new slope, the energy catch increased by 30 watt-hours, an essential boost, since the Sun is still low on Mars's horizon, from Spirit's perspective.
Meanwhile, the rover Opportunity is currently producing about 600 watt-hours per Martian day on the other side of the planet, in an area named Meridiani Planum. When the weather gets calm, Spirit will likely check out another so-called vesicular basaltic volcanic rock, similar to Esperanza. These rocks have a sponge-like surface, with large holes created by cavities of gas in molten lava.
Esperanza was the first type of volcanic vesicular basalt investigated on Mars. During the last nine months, the Spirit rover has remained in the same location at Low Ridge Haven.
Three weeks ago, it started moving around before being placed to safety. The rover is also bogged down by a front wheel that will not turn.
These machines were projected to last 90 days, but now they have been upgraded with new software, which permits them to operate a little more independently from ground controllers.
The new software improves their ability to map the landscape, detect obstacles and recognize the same object even when watched from different angles.
The rovers could also identify dust events, without the contribution of human Earth controllers, sifting through all of the images to detect them. The power shortage impeded Spirit to test most of its new software, but till now it has autonomously detected water ice clouds at 10 and 15 km (0.6-0.9 miles) in the Mars's atmosphere.