MER-A ("Spirit") is the first of the two Mars Exploration Rover Missions. It successfully landed on Mars on January 3, 2004. Its twin, Opportunity, is expected to land on Mars January 24, 2004.

Note: Days on Mars are called Sols, the landing date (January 3) of MER-A is considered Sol 1, Sol 2 is January 4 and notable as the rover first responded to NASA commands on Sol 2.

Table of contents
1 Landing Site: Columbia Memorial Station
2 Events and discoveries
3 Timeline
4 References

Landing Site: Columbia Memorial Station

MER-A landed in Gusev crater about 10 km from the center of the target ellipse at latitude 14.5718° S ± 30 meters, longitude 175.4785° E ± 0.5 meters [1]. A panorama [1] shows a slightly rolling surface, littered with small rocks, with hills on the horizon up to 27 km away. The MER team named the landing site "Columbia Memorial Station", in honor of the seven astronauts killed in the Space Shuttle Columbia disaster.

Events and discoveries

Sleepy Hollow

"Sleepy Hollow," a shallow depression in the Mars ground near NASA's Spirit rover, may become an early destination when the rover drives off its lander platform in a week or so. NASA scientists were very interested in this crater. It is 9 meters (30 feet) across and about 12 meters (40 feet) north of the lander.

First 3-D panorama of landing site: the crater under the sun is "Sleepy Hollow" received on January 5. ()

"Just as the ancient mariners used sextants for 'shooting the Sun,' as they called it, we were successfully able to shoot the Sun with our panorama camera, then use that information to point the antenna," said JPL's Matt Wallace, mission manger.

First color photograph

Below is the first color image of Mars taken by the panoramic camera on the Mars Exploration Rover Spirit. It is the highest resolution image ever taken on the surface of another planet. "We're seeing a panoramic mosaic of four pancam images high by three wide," said camera designer Jim Bell of Cornell. There are actually 12 million pixels in this image, it's 4,000 high by 3,000 wide. This, however, is only the tip of the iceberg, as this image, received on January 6, 2004, is about one eighth of a single pancam panorama and isn't stereo.

Part of the first color photograph sent from Spirit. The depression known as "Sleepy Hollow" is visible at the right of this photograph. (
Enlarge image)



  • June 6 - June 8 - Two launch attempts cancelled due to weather conditions at Kennedy Space Center.
  • June 10 - MER-A ("Spirit") was successfully launched aboard a Delta II rocket.


  • January 3 (Sol 1) JPL Images from 1/3/2004
    • 20:35 PST - MER-A landed in Gusev crater, however not exactly at its appointed landing spot within the crater (believed by scientists to once have been a crater lake). It later became apparent that the rover had landed six miles downrange from its planned landing site, but has landed in an area possibly even more favorable for the tests scientists want the rover to perform. Three decent images showed its progress as it came down. [1]
    • It returns black and white photographs via a relay through Mars-orbiting satellites.
  • January 4 (Sol 2) JPL Images from 1/4/2004
    • MER-A starts its first day of "work", receiving and responding to commands from NASA.
  • January 5 (Sol 3) JPL Images from 1/5/2004
    • The lander locks on its high-gain antenna and begins transmitting color photographs directly to Earth.
    • The first 3D Stereogram images are sent back from Spirit.
    • Four of five planned tests on scientific instruments on MER-A have been successful, the fifth instrument test is expected to occur later tonight. See Scientific instuments on the rovers.
  • January 6 (Sol 4) JPL Images from 1/6/2004
    • 08:00 PST - U.S. President George W. Bush calls JPL to congratulate the MER team for a successful landing.
    • The first high resolution, full color image is received from Spirit. [1]
    • Throughout the day, a series of high quality color images were sent from Spirit to NASA. During a news conference about the day's events Steve Squyres, science chief of the MER mission said "This is just a tiny taste of what's to come", refering to the first color images coming back.
    • 12:15 PST - The MER team decides to name the specific spot that Spirit landed on within the Gusev Crater "Columbia Memorial Station", in honor of the seven astronauts killed in the disaster. [1]
  • January 7 (Sol 5) JPL Images from 1/7/2004
    • 09:00 PST - Daily news briefing broadcast from JPL over NASA TV. A few new images are released, mainly polished versions of earlier images. Events from Sol 4 are reviewed, including a diagnostic test of a high gain antenna motor voltage spike(which occured on Sol 2), which did not show any problems and was attributed to debris in the antenna machine housing. Airbag retraction was continued on Sol 4. Sol 5 activities are discussed, scientists and engineers on the MER team are anxious to get Spirit separated from its lander and moving around the martian surface.
    • A plot is released by JPL showing the "Dust Optical Depth" of the Gusev Crater and Meridiani Planum areas of Mars. The plot shows a measure of the amount of dust in the martian atmosphere as taken by instruments on the orbiting Mars Global Surveyor satellite. Recent dust storms in December and January on Mars have greatly increased the amount of dust in the atmosphere around Meridiani Planum, the expected landing site of MER-A's sister rover Opportunity, landing 1/24/2004. It is unknown at this point if this increased dust activity will hinder Opportunity's mission. [1]
  • January 8 (Sol 6) JPL Images from 1/8/2004
    • 09:00 PST - Daily news briefing from JPL, apparently the activities to further retract the airbag under Spirit's lander were unsuccessful. On Sol 6 JPL engineers will try 6 rotations to try and force the partially deflated airbags fully under the lander. If this attempt fails, Spirit may have to turn itself around on the lander and attempt egress via another route.
    • Engineers will also begin Spirit's two step lifting process to "stand up" on the lander. Step 1 is to raise Spirit up on its back 4 wheels, and Step 2 is to deploy the currently retracted front wheels.
    • It is predicted that the airbag problem will delay Spirit's egress from the lander to January 14 or later. Currently the plan is to lift landing petal on the lander that Spirit is preparing travel down and attempt to tuck the excess airbag material under the petal. [1]
  • January 9 (Sol 7) JPL Images from 1/9/2004
    • During the night of Sol 6 Spirit successfully completed parts one and two of the "stand up" operation and now has its front wheels deployed and is almost ready to egress. Parts three and four of the stand up operation will be executed tonight. [1]
    • Images of data from Spirit's Mini-TES were released [1]
    • Another attempt to pack the inflated airbags under the ramp petals of the lander failed. Now JPL engineers will attempt to turn the rover around while still on the lander and egress down one of the other ramps on the lander. This activity has been practiced before MER mission launch and is expected to work.
  • January 10 (Sol 8) JPL Images from 1/10/2004
    • The Spirit Rover completed its stand up operation and is now standing with all six wheels deployed and locked, with one final connection between the lander and Spirit remaining.
  • January 11 (Sol 9) JPL Images from 1/11/2004
    • At the conclusion of Sol 8 the Spirit Rover's science arm, which features tools for digging into and taking close up images of rocks, was moved from its stowed launch position to its forward "drive" position.
  • January 12 (Sol 10) JPL Images from 1/12/2004
    • During Sol 9 the Spirit Rover performed science activities and returned data from the Pancam, completing the 360 panoramic image it took of its surroundings last week. Mini-TES data suggests more evidence that the Gusev site may have been a water filled lake.
    • Engineers plan the egress operation Spirit will begin on Sol 10 using a replica of the Spirit rover and lander. The tests go well, and no problems are expected.
  • January 13 (Sol 11) JPL Images from 1/13/2004
    • Sol 10 activities included successfully cutting the last link between the Spirit rover and lander. The first 45 degree turn was successful and the rover is preparing for egress. On Earth, mission details for the rover's exploration of the martian surface are being planned now that it is known exactly where Spirit is within Gusev.