Spirit (rover)

Spirit, also known as MER-A (Mars Exploration Rover – A) or MER-2, is a Mars robotic rover, active from 2004 to 2010. Spirit was operational on Mars for 2208 sols or 3.3 Martian years (2269 days; 6 years, 77 days). It was one of two rovers of NASA's Mars Exploration Rover Mission managed by the Jet Propulsion Laboratory (JPL). Spirit landed successfully within the impact crater Gusev on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, Opportunity (MER-B), which landed on the other side of the planet. Its name was chosen through a NASA-sponsored student essay competition. The rover got stuck in a "sand trap" in late 2009 at an angle that hampered recharging of its batteries; its last communication with Earth was on March 22, 2010.

The rover completed its planned 90-sol mission (slightly less than 92.5 Earth days). Aided by cleaning events that resulted in more energy from its solar panels, Spirit went on to function effectively over twenty times longer than NASA planners expected. Spirit also logged 7.73 km (4.8 mi) of driving instead of the planned 600 m (0.4 mi), allowing more extensive geological analysis of Martian rocks and planetary surface features. Initial scientific results from the first phase of the mission (the 90-sol prime mission) were published in a special issue of the journal Science.

On May 1, 2009 (5 years, 3 months, 27 Earth days after landing; 21 times the planned mission duration), Spirit became stuck in soft sand. This was not the first of the mission's "embedding events" and for the following eight months NASA carefully analyzed the situation, running Earth-based theoretical and practical simulations, and finally programming the rover to make extrication drives in an attempt to free itself. These efforts continued until January 26, 2010, when NASA officials announced that the rover was likely irrecoverably obstructed by its location in soft sand, though it continued to perform scientific research from its current location.

The rover continued in a stationary science platform role until communication with Spirit stopped on March 22, 2010 (sol 2208). JPL continued to attempt to regain contact until May 24, 2011, when NASA announced that efforts to communicate with the unresponsive rover had ended, calling the mission complete. A formal farewell took place at NASA headquarters shortly thereafter.

The scientific objectives of the Mars Exploration Rover mission were to:

Opportunity and Spirit rovers were part of the Mars Exploration Rover program in the long-term Mars Exploration Program. The Mars Exploration Program's four principal goals were to determine if the potential for life exists on Mars (in particular, whether recoverable water may be found on Mars), to characterize the Mars climate and its geology, and then to prepare for a potential human mission to Mars. The Mars Exploration Rovers were to travel across the Martian surface and perform periodic geologic analyses to determine if water ever existed on Mars as well as the types of minerals available, as well as to corroborate data taken by the Mars Reconnaissance Orbiter (MRO). Both rovers were designed with an expected 90 sols (92 Earth days) lifetime, but each lasted much longer than expected. Spirit's mission lasted 20 times longer than its expected lifetime, and its mission was declared ended on May 25, 2011, after it got stuck in soft sand and expended its power reserves trying to free itself. Opportunity lasted 55 times longer than its 90 sol planned lifetime, operating for 5498 days from landing to mission end. An archive of weekly updates on the rover's status can be found at the Opportunity Update Archive.

The MER-A (Spirit) and MER-B (Opportunity) were launched on June 10, 2003 and July 7, 2003, respectively. Though both probes launched on Boeing Delta II 7925-9.5 rockets from Cape Canaveral Space Launch Complex 17 (CCAFS SLC-17), MER-B was on the heavy version of that launch vehicle, needing the extra energy for Trans-Mars injection. The launch vehicles were integrated onto pads right next to each other, with MER-A on CCAFS SLC-17A and MER-B on CCAFS SLC-17B. The dual pads allowed for working the 15- and 21-day planetary launch periods close together; the last possible launch day for MER-A was June 19, 2003 and the first day for MER-B was June 25, 2003. NASA's Launch Services Program managed the launch of both spacecraft.

Spirit successfully landed on the surface of Mars on 04:35 Spacecraft Event Time (SCET) on January 4, 2004. This was the start of its 90-sol mission, but solar cell cleaning events would mean it was the start of a much longer mission, lasting until 2010. Spirit was targeted to a site that appears to have been affected by liquid water in the past, the crater Gusev, a possible former lake in a giant impact crater about 10 km (6.2 mi) from the center of the target ellipse at 14°34′18″S 175°28′43″E / 14.5718°S 175.4785°E / -14.5718; 175.4785. After the airbag-protected landing craft settled onto the surface, the rover rolled out to take panoramic images. These give scientists the information they need to select promising geological targets and drive to those locations to perform on-site scientific investigations. The MER team named the landing site "Columbia Memorial Station," in honor of the seven astronauts killed in the Space Shuttle Columbia disaster.