Spirit (rover)

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Spirit
NASA Mars Rover.jpg
Artistic view of a Mars Exploration Rover on Mars
Mission type Rover
Operator NASA
COSPAR ID 2003-027A
Website JPL's Mars Exploration Rover
Mission duration Planned: 90 Martian solar days (~92 Earth days)
Operational: 2269 days from landing to last contact (2208 sols)
Mobile: 1944 Earth days landing to final embedding (1892 sols)
Total: 2695 days from landing to mission end (2623 sols)
Spacecraft properties
Spacecraft type Mars Exploration Rover
Dry mass 185 kilograms (408 lb) (Rover only)
Start of mission
Launch date June 10, 2003 (2003-06-10)[1][2]
Rocket Delta II 7925-9.5[2][3]
Launch site Cape Canaveral SLC-17A
End of mission
Last contact 22 March 2010; 25 May 2011 (2011-05-26)[1]
Orbital parameters
Reference system Heliocentric (transfer)
Mars rover
Spacecraft component Rover
Landing date January 4, 2004, 04:35 UTC SCET
MSD 46216 03:35 AMT
Landing site Lua error in Module:Coordinates at line 668: callParserFunction: function "#coordinates" was not found.[4]
Distance covered 7.73 km (4.8 mi)
File:Nasa mer marvin.png
The launch patch for Spirit, featuring Marvin the Martian
Mars rovers (NASA)
← Sojourner Curiosity

Spirit, also known as MER-A (Mars Exploration Rover – A) or MER-2, is a robotic rover on Mars, active from 2004 to 2010.[1] It was one of two rovers of NASA's ongoing Mars Exploration Rover Mission. It landed successfully on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, Opportunity (MER-B), landed on the other side of the planet. Its name was chosen through a NASA-sponsored student essay competition. The rover became stuck in late 2009, and its last communication with Earth was sent on March 22, 2010.

The rover completed its planned 90-sol mission. 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),[5] 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.[6]

On May 1, 2009 (5 years, 3 months, 27 Earth days after landing; 21.6 times the planned mission duration), Spirit became stuck in soft soil.[7] 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 soil,[8] though it continued to perform scientific research from its current location.[9]

The rover continued in a stationary science platform role until communication with Spirit stopped on sol 2210 (March 22, 2010).[10][11] 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.[12][13][14][15] A formal farewell took place at NASA headquarters after the 2011 Memorial Day holiday and was televised on NASA TV.

The Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Office of Space Science, Washington.

Objectives

Delta II Heavy lifting off with MER-A on June 10, 2003

The scientific objectives of the Mars Exploration Rover mission were to:[16]

  • Search for and characterize a variety of rocks and soils that hold clues to past water activity. In particular, samples sought will include those that have minerals deposited by water-related processes such as precipitation, evaporation, sedimentary cementation or hydrothermal activity.
  • Determine the distribution and composition of minerals, rocks, and soils surrounding the landing sites.
  • Determine what geologic processes have shaped the local terrain and influenced the chemistry. Such processes could include water or wind erosion, sedimentation, hydrothermal mechanisms, volcanism, and cratering.
  • Perform calibration and validation of surface observations made by Mars Reconnaissance Orbiter instruments. This will help determine the accuracy and effectiveness of various instruments that survey Martian geology from orbit.
  • Search for iron-containing minerals, identify and quantify relative amounts of specific mineral types that contain water or were formed in water, such as iron-bearing carbonates.
  • Characterize the mineralogy and textures of rocks and soils and determine the processes that created them.
  • Search for geological clues to the environmental conditions that existed when liquid water was present.
  • Assess whether those environments were conducive to life.

NASA sought evidence of life on Mars, beginning with the question of whether the Martian environment was ever suitable for life. Life forms known to science require water, so the history of water on Mars is a critical piece of knowledge. Although the Mars Exploration Rovers did not have the ability to detect life directly, they offered very important information on the habitability of the environment during the planet's history.

Design and construction

Annotated rover diagram
Spirit rover images its lander on the surface of Mars on January 18/19, 2004 (Spirit Sol 16)[17]

Spirit (and its twin, Opportunity) are six-wheeled, solar-powered robots standing 1.5 meters (4.9 ft) high, 2.3 meters (7.5 ft) wide and 1.6 meters (5.2 ft) long and weighing 180 kilograms (400 lb). Six wheels on a rocker-bogie system enable mobility over rough terrain. Each wheel has its own motor. The vehicle is steered at front and rear and is designed to operate safely at tilts of up to 30 degrees. Maximum speed is 5 centimetres per second (2.0 in/s);[18] 0.18 kilometers per hour (0.11 mph), although average speed is about 1 centimetre per second (0.39 in/s). Both Spirit and Opportunity have pieces of the fallen World Trade Center's metal on them that were "turned into shields to protect cables on the drilling mechanisms".[19][20]

Solar arrays generate about 140 watts for up to four hours per Martian day (sol) while rechargeable lithium ion batteries store energy for use at night. Spirit's onboard computer uses a 20 MHz RAD6000 CPU with 128 MB of DRAM, 3 MB of EEPROM, and 256 MB of flash memory. The rover's operating temperature ranges from −40 to +40 °C (−40 to 104 °F) and radioisotope heater units provide a base level of heating, assisted by electrical heaters when necessary. A gold film and a layer of silica aerogel provide insulation.

Communications depends on an omnidirectional low-gain antenna communicating at a low data rate and a steerable high-gain antenna, both in direct contact with Earth. A low gain antenna is also used to relay data to spacecraft orbiting Mars.

Fixed science instruments include

The rover arm holds the following instruments

  • Mössbauer spectrometer (MB) MIMOS II – used for close-up investigations of the mineralogy of iron-bearing rocks and soils.
  • Alpha particle X-ray spectrometer (APXS) – close-up analysis of the abundances of elements that make up rocks and soils.
  • Magnets – for collecting magnetic dust particles.
  • Microscopic Imager (MI) – obtains close-up, high-resolution images of rocks and soils.
  • Rock Abrasion Tool (RAT) – exposes fresh material for examination by instruments on board.

The cameras produce 1024-pixel by 1024-pixel images, the data is compressed, stored, and transmitted later.

Mission overview

Spirit landing site, as imaged by MRO (December 4, 2006); click image to enlarge
An overall view of MER-A Spirit landing site (denoted with a star)

The primary surface mission for Spirit was planned to last at least 90 sols. The mission received several extensions and lasted about 2,208 sols. On August 11, 2007, Spirit obtained the second longest operational duration on the surface of Mars for a lander or rover at 1282 Sols, one sol longer than the Viking 2 lander. Viking 2 was powered by a nuclear cell whereas Spirit is powered by solar arrays. Until Opportunity overtook it on May 19, 2010, the Mars probe with longest operational period was Viking 1 that lasted for 2245 Sols on the surface of Mars. On March 22, 2010, Spirit sent its last communication, thus falling just over a month short of surpassing Viking 1's operational record. An archive of weekly updates on the rover's status can be found at the Spirit Update Archive.[21]

Spirit's total odometry as of March 22, 2010 (sol 2210) is 7,730.50 meters (4.80 mi).[22]

Mission timeline

2004

The Spirit Mars rover and lander arrived successfully on the surface of Mars on 04:35 Ground UTC 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.

Landing site: Columbia Memorial Station

Annotated Columbia Hills panorama from the Spirit landing site

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[23] at Lua error in Module:Coordinates at line 668: callParserFunction: function "#coordinates" was not found..[24]

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 panoramic image below shows a slightly rolling surface, littered with small rocks, with hills on the horizon up to 3 kilometers (1.9 mi) away.[25] The MER team named the landing site "Columbia Memorial Station," in honor of the seven astronauts killed in the Space Shuttle Columbia disaster.

"Sleepy Hollow," a shallow depression in the Mars ground at the right side of the above picture, was targeted as an early destination when the rover drove off its lander platform. NASA scientists were very interested in this crater. It is 9 meters (30 ft) across and about 12 meters (39 ft) north of the lander.

First color image

First color image compiled from images by Spirit; it was the highest resolution color image taken on another planet.

To the right is the first color image derived from images taken by the panoramic camera on the Mars Exploration Rover Spirit. It was the highest resolution image taken on the surface of another planet. According to the camera designer Jim Bell of Cornell University, the panoramic mosaic consists of four pancam images high by three wide. The picture shown originally had a full size of 4,000 by 3,000 pixels. However, a complete pancam panorama is even 8 times larger than that, and could be taken in stereo (i.e., two complete pictures, making the resolution twice as large again.) The colors are fairly accurate. (For a technical explanation, see colors outside the range of the human eye.)

The MER pancams are black-and-white instruments. Thirteen rotating filter wheels produce multiple images of the same scene at different wavelengths. Once received on Earth, these images can be combined to produce color images.[26]

Sol 17 (January 21, 2004) flash memory management anomaly

On January 21, 2004 (sol 17), Spirit abruptly ceased communicating with mission control. The next day the rover radioed a 7.8 bit/s beep, confirming that it had received a transmission from Earth but indicating that the craft believed it was in a fault mode. Commands would only be responded to intermittently. This was described as a very serious anomaly, but potentially recoverable if it were a software or memory corruption issue rather than a serious hardware failure. Spirit was commanded to transmit engineering data, and on January 23 sent several short low-bitrate messages before finally transmitting 73 megabits via X band to Mars Odyssey. The readings from the engineering data suggested that the rover was not staying in sleep mode. As such, it was wasting its battery energy and overheating – risk factors that could potentially destroy the rover if not fixed soon. On sol 20, the command team sent it the command SHUTDWN_DMT_TIL ("Shutdown Dammit Until

Adirondack
Adirondacksquare.jpg
Rat post grind.jpg
Above: An approximate true-color view of Adirondack, taken by Spirit's pancam.
Right:Digital camera image (from Spirit's Pancam) of Adirondack after a RAT grind (Spirit's rock grinding tool)
Feature type Rock
Coordinates Lua error in Module:Coordinates at line 668: callParserFunction: function "#coordinates" was not found.

Looking back from Bonneville crater to the landing site 
False color image of "Mimi". 

Close-up of the rock Mazatzal, which was ground with the Rock Abrasion Tool on sol 82 

Rover tracks up to sol 85 from Mars Global Surveyor 
Spirit on Sept. 29, 2006 beside Home Plate [94] 

Map of the movement of the Spirit rover up to 2008. 

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External links

JPL, MSSS, and NASA links

Other links