Spirit launched June 10, 2003, softlanded January 4, 2004 (UT) in
Gusev crater (14.82 S, 184.85 W).
Opportunity launched July 7, 2003, softlanded January 25, 2004 (UT) in Meridiani Terra (2.07 S, 6.08 W).
Originally, this mission was developed as Mars Surveyor 2003, when the Mars Surveyor Lander/Rover 2001 was cancelled in consequence of the loss of the 1998/99 Mars Polar Lander.
It consists of two Nasa sister spacecraft (Mars Exploration Rover A and B, or 2 and 1; note Spirit is MER-A or MER-2, Opportunity is MER-B or MER-1), which should fly to and explore Mars using the launch opportunity before the 2003 Mars Opposition - as does ESA's Mars Express. This mission was redefined in 1999, and now omits a stationary lander, which was to contain imaging system and various instruments to study radiation and soil. Instead, it consists of a large rover (Athena, ~130 kg) which is to land similar to Mars Pathfinder of 1996 in direct approach and airbag buffered. It is to photograph and investigate samples from a 10 km range around the landing site, with a sampling arm and store for investigation.
Our image above right shows an artist's conception of the Mars Exploration Rover as roving over the Martian surface.
Originally, Athena was to load the samples into a soccer ball-sized container, which would have been blasted into orbit around Mars and picked up and delivered back to Earth by a later mission. Landing scheduled for January 4, 2004 (MER-A) and January 25, 2004 (MER-B). The rovers should investigate their landing site regions for at least 90 days.
On November 7, 2002 the Mars Exploration Rover MER 2 (A) did its very first driving exercise at JPL, while MER 1 (B) was undergoing a Mars landing simulation - both tests were success (JPL News Release Nov 12, 2002). The rovers were transported to Kennedy Space Center, Cape Canaveral, Florida in February and March 2003; MER 2 arrived on February 24, MER 1 followed in early March.
On June 8, 2003, on the occasion of the first launch attempt of MER-A, the twin robots were named "Spirit" (MER-A, or 2) and "Opportunity" (MER-B or 1), see Nasa Press Release 2003-081.
Mars Exploration Rover A (Spirit) blasted off in a picturebook launch from Pad 17-A of Kennedy Space Center with a Delta II on June 10, 2003 (1:58:47 p.m. EDT), and went on its interplanetary cruise to Mars, which reached the Red Planet on January 4, 2004 (UT; January 3, PST).
Mars Exploration Rover B (Opportunity) is lifted off from Pad 17-B with a Delta II on July 7, 2003 (11:18:15 p.m. EDT), and 83 minutes later, was boosted out of Earth orbit onto its interplanetary cruise to Mars (See JPL press release, also Launch Event Details.) Opportunity is en route to reach Mars on January 25, 2004 (UT; January 24, PST).
Landing sites for the two rovers have been selected (April 11, 2003): For Spirit, the Gusev Crater was selected, while Opportunity was chosen to land in Meridiani Terra (see map). Previously (January 14, 2003), four landing site had been selected for consideration; besides the two "winners," the other sites have been the Hematite site and Isidis (close to the landing site of Mars Express' Beagle 2 lander).
On January 4, 2004, 4:35 UT (January 3, 8:35 p.m. PST), the Mars Exploration Rover Spirit, after an interplanetary cruise of almost half a year and 487 million km (303 million miles) touched down softly on red planet Mars, in the intended landing site region, Gusev Crater, 184.8d W, 14.8d S. It had entered the Martian atmosphere at multiple bullet speed, slowed down by atmospheric friction and paracute, and eventually, buffered by airbags, fell down, bounced and rolled to its final landing place. Immediately after touchdown, Spirit transmitted a first "Hello" message to indicate its safe state, followed shortly after by a first high-quality photograph of the landing site (see press release). It commenced intense photographic survy, delivering its first stereoscopic images on January 5 and its first color photographs on January 6, 2004 (also see the most detailed early color image from Spirit). This landing site, a vast flatland in crater Gusev, was named "Columbia Memorial Station" to honor the seven astronauts who died in the tragic accident of Space Shuttle Columbia in February 2003. Later, Martian landscape details near the Spirit landing site were dedicated to the Apollo 1 crew (Grissom, White and Chaffee), and to Columbia's seven astronauts. On January 9, Spirit turned itself into a real rover by lowering its front wheels, and one day later, sood up to its full height of 1.45 meters. A major scientific result was obtained on January 9 by presumably finding carbonates at the landing site with the MiniTES spectrometer. On January 12, a first full-color panorama was completed. January 13 and 14, rover Spirit turned around about 120 degrees on its lander to avoid an airbag blocking its way down to Mars' surface. On January 15, Spirit eventually rumbled down its lander platform, to the Martian surface, and became the second functional Mars roving vehicle, or mobile laboratory, after Mars Pathfinder's Sojourner of 1996. A first very sharp close-up image was taken on the day after rolldown. Spirit is now busily touring the red Martian desert on its exploration trip, taking photographs and studying the landing site region. A first target was a rock called 'Adirondack', where first investigations with Spirit's instruments, a microscope and two up-close spectrometers, yielded surprising soil analysis results. Communication problems occurred on January 21, Spirit's 18th day on Mars, or Sol 18,, when Spirit only shortly acknowledged receiving commands but didn't transmit any further data. Also on January 22, Spirit only acknowledged having received a transmission from Earth, but on January 23, the rover reestablished connection and, in a first session window, transmitted data for 20 minutes, and continued to recover the next day by reacting to commands. It resumed taking pictures on January 29 and got back to regular work the next day, and was declared "restored to health" on February 1. After getting its flash memory formatted, Spirit started normal research activity, continuing the investigation of rock Adirondack. After drilling a hole into this rock, Spirit started to drive beyond this rock, toward a crater nicknamed "Bonneville." On this way, Spirit passed a cluster of roccks dubbed "Stone Council," and flawlessly also communicated with European Mars Express, in addition to the US orbiters Mars Global Surveyor and 2001 Mars Odyssey.
Mars Exploration Rover Opportunity had a correction maneuver, the first after four months, on January 16, 2004, just little more than a week and 12.5 million km (7.8 million miles) before arriving at Mars. After an interplanetary cruise of more than 6 month, Mars Exploration Rover Opportunity successfully touched down on January 25, 2004, 5:05 UT (January 24, 2004, 9:05 p.m. PST) at its intended landing site Meridiani Terra (2.07 S, 6.08 W). Like its sister craft, it had entered the Martian atmosphere at multiple bullet speed, slowed down by atmospheric friction and paracute, and eventually, buffered by airbags, fell down, bounced and rolled to its final landing place; Opportunity happened to end up upside-down. Opportunity transmitted a first "Hello" message to indicate its safe state immediately after touchdown, followed shortly after by several high-quality photographs of the landing site, including a first color image showing this much smoother and darker terrain compared to the previously investigated sites. Opportunity passed general "health checks" on January 26. Layers of Mars rocks On January 28 and 29, Opportunity erected itself to full size and rolled off its lander on January 31. The Opportunity landing site was memorialized as the Challenger Memorial Station on January 28, 2004, the 18th anniversary of the tragic Space Shuttle Challenger accident. Opportunity extended its arm on February 2, and consequently used its microscope to investigate Martian soil beneath its wheels. It was set to investigate rocks in the exposed outcrop on February 5, and started to roll to the outcrop field, nicknamed "Opportunity Ledge." Opportunity is now known to sit in a small crater 22 meters (72 feet) in diameter. The rover continued to investigate the outcrop field near its landing site.
MER on Mars (640x480, 1024x768) - MER Flight Configuration
Spirit launch on June 10, 2003
Opportunity launch on July 7, 2003
Trajectory of Mars Exploration Rovers
Mars Exploration Rovers landing sites - newer map with MER sites only
Spirit landing site in Gusev Crater
Opportunity landing site in Meridiani Terra
Spirit's first look on Mars
Opportunity's first color panorama
Last Modification: January 25, 2004