Spirit Mars Rover Mission Information

Fast Facts: Spirit traveled about 500 million kilometers (311 million miles) on its journey to Mars.

A day - or sol - on Mars is 24 hours, 39 min, 35 sec (1.027 Earth days). Spirit was expected to operate for at least 91 sols on Mars. It continues to operate.

Spirit carried a memorial to the crew of the Space Shuttle Columbia to the surface of Mars.

Spirit Mars Rover Mission Information: The "Spirit" rover (Mars Exploration Rover A) is one of the two rovers launched to Mars in mid-2003. The Mars Exploration Rover consists of a box-like chassis mounted on six wheels. The chassis contains the warm electronics box (WEB). On top of the WEB is the triangular rover equipment deck, on which is mounted the Pancam mast assembly, high gain, low gain, and UHF antennas, and a camera calibration target.

Attached to the two forward sides of the equipment deck are solar arrays which are level with the deck and extend outward with the appearance of a pair of swept-back wings. Attached to the lower front of the WEB is the instrument deployment device, a long hinged arm which protrudes in front of the rover.

The rover carries a suite of instruments for science and navigation. The panoramic camera (Pancam) and navigation cameras are mounted on top of the Pancam mast assembly, at a height of about 1.4 meters from the base of the wheels.

The mast, mounted at the front of the equipment deck, also acts as a periscope for the Miniature Thermal Emission Spectrometer (Mini-TES). Attached to the end of the instrument deployment device are the Alpha Particle X-Ray Spectrometer (APXS), Mossbauer Spectrometer (MB), Microscopic Imager (MI), and Rock Abrasion Tool (RAT). A magnet array is attached to the front of the equipment deck. Two hazard avoidance cameras are mounted on the front of the rover and two on the rear. The group of science instruments (Pancam, Mini-TES, APXS, MB, MI, and RAT) is known as the Athena science package.

Spirit was launched on a standard Delta II 7925 on 10 June 2003 at 17:58:46.773 UT. After insertion into a circular Earth parking orbit, the spacecraft was despun and the third stage was reignited to put the craft on a trajectory to Mars, after which the aeroshell, lander, and rover separated from the third stage. The cruise phase to Mars ended on 20 November 2003, 45 days before Mars entry. The approach phase lasted from this date until martian atmospheric entry on 4 January 2004. On entry the lander and components had a mass of 827 kg and were travelling at 19,300 km/hr. The aeroshell decelerated the lander in the upper martian atmosphere for about four minutes to a velocity of 1600 km/hr, followed by deployment of a parachute. The parachute slowed the spacecraft to about 300 km/hr. A series of tones was transmitted by the spacecraft during entry and after landing to indicate the successful completion of each phase. Just prior to impact, at an altitude of about 100 m, retrorockets slowed the descent and airbags were inflated to cushion the impact. The craft hit at roughly 50 km/hr and bounced and rolled along the surface. After it stopped the airbags deflated and retracted, the petals opened, and the rover deployed its solar arrays. The landing took place at 04:35 UT on 4 January 2004 (Earth received time), (11:35 p.m. Jan. 3 EST) approximately 2:00 p.m. local time, about one hour before Earth set, in Gusev Crater, roughly 15 degrees south of the equator. On Mars it is the latter half of southern summer. The landing ellipse is centered at 14.82 S, 184.85 W and is 96 km by 19 km oriented at 76 degrees. About three hours after landing the first images were returned to Earth, showing a flat plain littered with small rocks. Gusev Crater was chosen as a landing site because it has the appearance of a crater lakebed. If Gusev was at one time filled with water, the bottom of the crater may contain sedimentary deposits laid down in the submarine environment.

An egress phase took place over the first few days, involving deployment of the Pancam mast and high gain antenna, rover stand up, imaging and calibration, and selection of proper egress path. The rover drove off the platform onto the surface of Mars on 15 January at 8:41 UT (3:41 a.m. EST). Over a year of surface operations, involving driving the rover, imaging, and use of the science instruments has already been achieved, and the rovers have had their missions extended.