Spirit rover
|
|
Spirit (official designation: MER-A) is the first of the two Mars Exploration Rover Missions. She successfully landed on Mars on January 3, 2004 at 20:35 PST (04:35 UTC on January 4). Her twin Opportunity landed successfully on Mars on January 24, 2004.
PIA05248_label.jpg
| Contents |
Naming of Spirit and Opportunity
The Spirit and Opportunity rovers were named via a student essay competition, from a winning entry by Sofi Collis, a 9 year old 3rd grade student from Arizona.
I used to live in an Orphanage.
It was dark and cold and lonely.
At night, I looked up at the sparkly sky and felt better.
I dreamed I could fly there.
In America, I can make all my dreams come true.....
Thank-you for the "Spirit" and the "Opportunity"
—Sofi Collis, age 9
See NASA Names Mars Exploration Rovers Spirit and Opportunity (http://www.planetary.org/html/news/articlearchive/headlines/2003/rovers_named.html)
Landing site: Columbia Memorial Station
Spirit landed in Gusev crater about 10 km from the center of the target ellipse (http://marsoweb.nas.nasa.gov/landingsites/mer2003/topsites/final/Gusev/) at latitude 14.5718° S ± 30 meters, longitude 175.4785° E ± 0.5 meters [1] (http://www.spaceflightnow.com/mars/mera/040113exploration.html). The rover, parachute, heatshield and several bounce marks are visible in a picture taken by Mars Global Surveyor (http://www.jpl.nasa.gov/mer2004/rover-images/jan-23-2004/captions/image-12.html).
A panorama [2] (http://antwrp.gsfc.nasa.gov/apod/ap040114.html) 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.
On January 27 NASA memorialized the crew of Apollo 1 by naming three hills to the north of "Columbia Memorial Station" as the Apollo 1 Hills. On February 2, the astronauts on Columbia's final mission were further memorialized when NASA named a set of hills to the east of the landing site the Columbia Hills Complex, denoting seven peaks in that area Anderson, Brown, Chawla, Clark, Husband, McCool and Ramon. (NASA has submitted these geographical feature names to the IAU for approval.)
Events and discoveries
Timeline
A detailed chronology of events and discoveries may be found in the Spirit rover timeline entry. The following paragraphs discuss the more notable findings.
Sleepy Hollow
"Sleepy Hollow," a shallow depression in the Mars ground near NASA's Spirit rover, 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 feet) across and about 12 meters (40 feet) north of the lander.
"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
To the right 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.
January 21 flash memory management anomaly
On January 21 (Sol 18), 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 spacecraft believed it was in a fault mode. This was described as a very serious anomaly, but potentially recoverable if it was 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. This suggested difficulties with the rover's high-gain antenna. The rover had also been in a processor reset loop of some type since Wednesday, in which the processor would repeatedly wake, load the flight software, and uncover a condition that would cause it to reset. The processor was not resetting immediately, however, with a delay of up to an hour. Indications were that the cause of the reset was not always perceived by the rover's diagnostics to be the same each time.
On January 24 the rover repair team announced that the problem was with Spirit's flash memory and the software that wrote to it. Spirit was placed in "crippled mode," operating using RAM instead of flash. In this mode, the rover obeyed commands about communicating and going into sleep mode. Spirit communicated successfully at 120 bits per second for nearly an hour. The flash hardware was in fact believed to be working correctly but the file management module in the software was "not robust enough" for the operations the Spirit was engaged in when the problem occurred, indicating that the problem was caused by a software bug as opposed to faulty hardware.
The engineers indicated that they had initially believed that this was a serious problem, and as a result, performed operations that only exacerbated the minor situation. NASA engineers finally came to the conclusion that there were too many files on the filesystem, which was a relatively minor problem. Most of these files contained unneeded in-flight data. After realizing what the problem was, the engineers deleted some files, and eventually reformatted the entire flash memory system. On February 6 (Sol 33), the rover was restored to its original working condition, and science activities resumed.
History's first grinding of a rock on Mars
The round, shallow depression in this image resulted from history's first grinding of a rock on Mars. The Rock Abrasion Tool on NASA's Spirit rover ground off the surface of a patch 45.5 millimeters (1.8 inches) in diameter on a rock called Adirondack during Spirit's 34th sol on Mars, Feb. 6, 2004. The hole is 2.65 millimeters (0.1 inch) deep, exposing fresh interior material of the rock for close inspection with the rover's microscopic imager and two spectrometers on the robotic arm. This image was taken by Spirit's panoramic camera, providing a quick visual check of the success of the grinding. The rock abrasion tools on both Mars Exploration Rovers were supplied by Honeybee Robotics, New York, N.Y.
"The RAT performed beyond our expectations," beamed Steve Gorevan, of Honeybee Robotics, New York, lead scientist for the rock abrasion tools on both rovers. "With the docile cutting parameters we set, I didn't think that it would cut this deep. In fact, when we saw virtually a complete circle, I was thrilled beyond anything I could have ever dreamed. Following up that glorious circular brushing - it's like back-to-back homers."
Mimi
This color image taken by the Mars Exploration Rover Spirit's panoramic camera on Sol 40 is centered on an unusually flaky rock called Mimi. Mimi is only one of many features in the area known as "Stone Council", but looks very different from any rock that scientists have seen at the Gusev crater site so far. Mimi's flaky appearance leads scientists to a number of hypotheses. Mimi could have been subjected to pressure either through burial or impact, or may have once been a dune that was cemented into flaky layers, a process that sometimes involves the action of water.
Humphrey and clues for water
On March 5, 2004, NASA announced that Spirit had found hints of water history on Mars in a rock dubbed "Humphrey". Dr. Ray Arvidson of Washington University, St. Louis, reported during a NASA press conference: "If we found this rock on Earth, we would say it is a volcanic rock that had a little fluid moving through it." In contrast to the rocks found by the twin rover Opportunity, this one was formed from magma and then acquired bright material in small crevices, which look like crystallized minerals. If this interpretation holds true, the minerals were most likely dissolved in water, which was either carried inside the rock or interacted with it at a later stages, after it formed. (Press release (http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20040305a.html))
Bonneville Crater
Bonneville_Crater_look_back.jpg
On March 11, 2004, the Spirit rover reached Bonneville crater after a 400 yard journey. This crater is 150 yards across and about 30 yards deep. JPL decided that it would be a bad idea to send the rover down into the crater, as they saw no targets of interest inside. Spirit drove along the southern rim, tore up some sand dunes, and continued to the southwest towards the Columbia Hills.
Spirit_tracks.gif
Missoula Crater
Missoula_spirit.jpg
Spirit reached Missoula crater on Sol 105. The crater is roughly 100 yards across and 20 yards deep. Missoula crater was not considered a high priority target due to the older rocks it contained. The rover skirted the northern rim, and continued to the southeast.
Lahonten Crater
Lahonten_crater.jpg
It then reached Lahonten crater on Sol 118, and drove along the rim until Sol 120. Lahonten is about 60 yards across and about 10 yards deep. A long, snaking sand dune stretches away from its southwestern side, and spirit went around it.
Columbia Hills
Pot_of_gold-Close-med.jpg
On Sol 159, Spirit reached the first of many targets at the base of the Columbia Hills called West Spur. Hank's Hollow was studied for 23 sols. Within Hank's Hollow was the strange looking rock dubbed "Pot of Gold".
From here, Spirit took a northernly path along the base of the hill towards the target Wooly Patch, which was studied from Sol 192 to Sol 199. By Sol 203, Spirit had driven southward up the hill and arrived at the rock dubbed "Clovis". Clovis was grinded and analyzed from Sol 210 to Sol 225. Following Clovis came the targets of Ebenezer (Sols 226-235), Tetl (Sol 270), Uchben and Palinque (Sols 281-295), and Lutefisk (Sols 296-303). From Sols 239 to 262, Spirit powered down for solar conjunction.
Sol326_from149-med.jpg
Slowly, Spirit has made its way around the summit of Husband Hill, and at Sol 344 is ready to climb over the newly designated "Cumberland Ridge" and into "Larry's Lookout" and "Tennessee Valley".
On Sol 371, Spirit arrived at a rock named "Peace" near the top of Cumberland Ridge. Spirit grinded it with the RAT tool on Sol 373.
By Sol 390 (Mid-February 2005), Spirit was advancing towards "Larry's Lookout", by driving up the hill backwards in reverse. The scientists at this time are trying to conserve as much energy as possible for the climb.
Spirit also investigated some targets along the way, including the soil target, "Paso Robles", which contained the highest amount of salt found on the red planet. The soil also contained a high amount of phosphorus in its composition, however not nearly as high as another rock sampled by Spirit, "Wishstone". Squyres said of the discovery, "We're still trying to work out what this means, but clearly, with this much salt around, water had a hand here".
On 9 March 2005 (probably during martian night), the rover's solar panel efficiency jumped from around 60% of what it had originally been to 93%, followed on 10 March by the sighting of dust devils. NASA scientists speculate a dust devil must have swept the solar panels clean, possibly significantly extending the duration of the mission. This also marks the first time dust devils had been spotted by either Spirit or Opportunity, easily one of the top highlights of the mission to date. Dust devils had previously been photographed by only the Pathfinder probe.
Astronomy
Spirit pointed its cameras towards the sky and observed a transit of the Sun by Mars' moon Deimos (see Transit of Deimos from Mars). It also took the only photo of Earth from another world on early March.
A transit of Mercury from Mars took place on January 12 2005 from about 14:45 UTC to 23:05 UTC. Theoretically, this could have been observed by both Spirit and Opportunity, however camera resolution did not permit seeing Mercury's 6.1" angular diameter. They were able to observe transits of Deimos across the Sun, but at 2' angular diameter, Deimos is about 20 times larger than Mercury's 6.1" angular diameter. Ephemeris data generated by JPL Horizons (http://ssd.jpl.nasa.gov/horizons.html) indicates that Opportunity would have been able to observe the transit from the start until local sunset at about 19:23 UTC Earth time, while Spirit would have been able to observe it from local sunrise at about 19:38 UTC Earth time until the end of the transit.
Honors
Honoring Spirit's great contribution to the exploration of Mars, the asteroid 37452 has been named Spirit. The name was proposed by Ingrid van Houten-Groeneveld who along with Cornelis Johannes van Houten and Tom Gehrels discovered the asteroid on September 24, 1960.
Related articles
External links
- SpaceFlightNow Status Page (http://spaceflightnow.com/mars/mera/status.html)
- Mission Status updates from NASA JPL (http://www.jpl.nasa.gov/mer2004/mission-status/index.html)
- Marsbase.net (http://www.marsbase.net/), a site that tracks time on Mars.
- Planetary Photojournal (Mars) (http://photojournal.jpl.nasa.gov/targetFamily/Mars), NASA JPL's Planetary Photojournal for Mars.
- JPL's Mars Exploration Rover home page (http://www.jpl.nasa.gov/mer2004/index.html)
- NASA TV Special Events Schedule (http://www.nasa.gov/multimedia/nasatv/MM_NTV_Breaking.html) for MER News Briefings at JPL
- MAESTRO - public version of rover simulation software (http://mars.telascience.org)
- FAQ for Maestro and links to other amateur sites (http://firasd.org/misc/mars/faq.html)
- Cornell's rover site: Athena (http://athena.cornell.edu/)
- Finding Spirit: high resolution images of landing site (Mars Global Surveyor - Mars Orbiter Camera) (http://www.msss.com/mars_images/moc/2004/01/23/)
- Finding Spirit: interactive Mars atlas based on Viking images: you can zoom in/out and pan images, to find your preferred site. "Spirit" approximate position is 14.82°S (= -14.82°N) , 184.85°W (= 5.15°E) (http://www.roving-mouse.com/planetary/Mars/Atlas/clickable-globe.html)
- (AXCH) 2004 Mars Exploration Rovers Highlights (http://axonchisel.net/etc/space/mars-exp-rover-highlights.html) - News, status, technical info, history, and more.
- Wikisource:NASA MER press briefings (http://sources.wikipedia.org/wiki/NASA_MER_press_briefings)
- New Scientist on Spirit Dust Devils (http://www.newscientist.com/article.ns?id=dn7140)de:Spirit