Transcript MER

Mars Exploration Rovers and Two Year Highlights
Assembly, Test and Launch
Rover
Two Earth Year Highlights of the Rovers
Spirit
Opportunity
Reference Information
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MER and Mars Pathfinder Rovers at JPL
Spirit and Opportunity during assembly and
test at the Jet Propulsion Laboratory shown
with the Mars Pathfinder engineering model
rover (first to operate on Mars in July 1997).
Spirit
Mars Pathfinder
Sojourner Engineering
Rover Model
Opportunity
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MER-A Spacecraft/Spirit Rover Stack-up
MER-A spacecraft atop the
Delta II launch vehicle at Space
Launch Complex 17-A, Cape
Canaveral, FL.
MER-A Spacecraft
with Spirit Rover in
Aeroshell
Payload
Fairing
Half
Stage III
Stage II
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MER-A/Spirit Rover Launch
MER-A spacecraft launched by
the Delta II 7925 at Pad 17-A,
Cape Canaveral, FL on June 10,
2003.
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MER-B/Opportunity Rover Launch
MER-B spacecraft launched
by the Delta II 7925H at Pad
17-B, Cape Canaveral, FL
on July 7, 2003.
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Mars Exploration Rover
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First Look from Spirit on Mars
January 3, 2004 - Spirit lands on Mars
January 4, 2004 - This mosaic image taken by the navigation camera on Spirit shows a
panoramic view of the rover on the surface of Mars in Gusev Crater. The crater is about 93
miles in diameter. A surface depression nicknamed “Sleepy Hollow” can be seen to the left of
center. It is an impact crater 30 feet across and located about 40 feet north of Spirit.
The airbags, shown on the far right and left, failed to fully deflate postponing Spirit’s egress
off the landing craft. The rover turns on the lander and drives down one of the other lander
ramps onto the Martian surface on January 15.
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Spirit Observes Bonneville Crater and Columbia Hills
March 12 and 13, 2004 - This mosaic is an approximate true color image from Spirit’s panoramic
camera showing “Bonneville” Crater and the rover's next destination named the “Columbia Hills,”
seen in the upper right. The crater is about 650 feet in diameter and about 90 feet deep. After two
months of travel to Bonneville, the impact crater was a big disappointment. There are no layered
rocks, it is shallow, filled with sand and dust, the walls are lined with the same shattered basalt
seen previously in Gusev Crater and no evidence of sediment below the basalt.
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Spirit Observes Earth
NASA/JPL-Caltech/Cornell/TexasA&M
March 13, 2004 - This is the first image ever taken of Earth from the surface of a planet beyond
the Moon. Spirit took the image one hour before sunrise on the 63rd Martian day of its mission.
The image is a mosaic of images taken by the rover's navigation camera showing a broad view of
the sky, and an image taken by the rover's panoramic camera of Earth.
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Spirit Finds First Evidence of Water at Gusev
June 13, 2004 - This false-color image taken
by the Spirit panoramic camera shows the
rock dubbed “Pot of Gold” (upper center),
located near the base of the “Columbia
Hills” in Gusev Crater. The rock is about the
size of a softball.
The insides of the rocks appear to have
been eroded, while their outer rinds remain
in tact. These outer rinds are reminiscent of
those found on rocks at Meridiani Planum's
“Eagle Crater” by Opportunity.
June 25, 2004 - This 1.2 inches by 1.2 inches close-up image
taken by Spirit highlights the nodular nuggets that cover the
rock “Pot of Gold.” These features appear to stand on the end
of stalk-like projections. Data from the rover's scientific
instruments has shown the “Pot of Gold” contains the mineral
hematite. Hematite, found on Earth, can be formed in three
different ways: in standing water; in small amounts of hot
fluids (hydrothermal processes); and in volcanic rock.
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Spirit Perched Above Gusev Crater
Gusev Crater
Rim
August 5, 2004 - This approximate true-color image taken by Spirit shows a rock outcrop dubbed
“Longhorn,” and behind it, the sweeping plains of Gusev Crater. On the horizon, the rim of Gusev
Crater is clearly visible. The view is to the south of the rover. The Longhorn outcrop measures
about 18 feet wide and 5 feet high.
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Spirit Finds Evidence Water Flowed Through Rock
August 13, 2004 - This
approximate true-color image
taken by the Spirit panoramic
camera shows the rock outcrop
dubbed “Clovis” about 30 feet
above the plains of Gusev
Crater. The rock was softer than
other rocks studied so far at
Gusev. The rover easily ground
a hole into Clovis with its rock
abrasion tool.
Analysis of the interior of the
hole with the rover's scientific
instruments found higher
concentrations of sulfur, bromine
and chlorine compared to
basaltic (volcanic) rocks at
Gusev. This might indicate that
Clovis was chemically altered,
and that fluids once flowed
through the rock depositing
these elements. This suggests
that water may once have been
active at Gusev.
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Spirit Views Husband Hill Summit Destination
February 27 to March 2, 2005 – Spirit’s panoramic camera acquired this view from a position
known as “Larry's Lookout” along the drive up “Husband Hill.” The summit of Husband Hill is the
far peak near the center, and it is about 656 feet from the rover and about 148 feet higher in
elevation. The bright rocky outcrop near the center of the panorama is part of the “Cumberland
Ridge.” Beyond to the left is the “Tennessee Valley.”
Spirit's tracks leading back from the “West Spur” region can be seen on the right side of the
panorama. The region just beyond the area where the tracks made their “zig-zag” is the area
known as “Paso Robles,” where Spirit discovered rock and soil deposits with very high sulfur
abundances. After obtaining this mosaic, Spirit drove around the Cumberland Ridge rocks and
drove up the flank of Husband Hill heading toward its summit.
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Spirit Reaches the Summit of Husband Hill
August 23, 2005 - This image was taken by Spirit just as the rover completed its climb up
“Husband Hill” inside Gusev Crater. The summit is about the height of the Statue of Liberty (305
feet). It appears to be a windswept plateau of scattered rocks, little sand dunes and small
exposures of outcrop. The view is looking toward the north, down into the drifts and outcrops of
the “Tennessee Valley,” a region that Spirit was not able to reach during its climb to the top of the
hill. The approximate true-color view consists of images obtained by the rover's panoramic
camera.
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Spirit Investigates Husband Hill Summit
August 24 to 27, 2005 - The image is an approximate true-color rendering. The panoramic camera
on Spirit took the hundreds of images that combined into this view from the “Husband Hill Summit.”
The panorama provided the first view of the “Inner Basin” region (center of the image), including the
feature “Home Plate,” its next destination. After investigating the summit area, Spirit drove downhill
to get to the Inner Basin region. Spirit arrived at the summit from the west, along the direction of the
rover tracks seen in the middle right. The peaks of “McCool Hill” and “Ramon Hill” can be seen on
the horizon near the center of the panorama. Spirit spent more than a month exploring the summit
region, measuring the chemistry and mineralogy of soils and rocky outcrops at the peak of Husband
Hill for comparison with similar measurements obtained during the ascent.
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Spirit Views Rippled Sand Deposits
December 30, 2005 and January 1, 2006 - Spirit welcomed the beginning of 2006 by taking this
panorama of intricately rippled sand deposits in Gusev Crater. This is an approximate true-color
rendering of the “El Dorado” ripple field. The view consists of images acquired by the Spirit
panoramic camera. The seams between individual frames in the sky portion of the mosaic have
been eliminated to better simulate the vista a person standing on Mars would see. Spirit spent
several days acquiring images, spectral data, and compositional and mineralogical information
about these large sand deposits before continuing downhill toward “Home Plate.”
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Opportunity Captures Eagle Crater Panorama
January 24, 2004 - Opportunity lands halfway around Mars from Spirit
April 14, 2004 - Opportunity surveys the dusty plain of Meridiani. This image is an approximate truecolor panorama mosaic showing “Eagle Crater” and some of the surrounding plains of Meridiani
Planum. This panorama depicts a story of exploration including the rover's landing craft, a thorough
examination of the outcrop, a study of the soils at the near-side of the lander, and a successful exit
from Eagle Crater. The impact crater is about 72 feet in diameter and about 6 feet deep.
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Opportunity Finds Evidence of Martian Water
March 8, 2004 - The first outcrop rock Opportunity examined
with the microscopic imager was finely-layered, buff-colored and
in the process of being eroded by windblown sand. Embedded
and on top of the rock, like “blueberries” in a muffin, were small
spherical grains about 0.06 inches in size. The image shows the
gray spheres that have weathered out of the rock and are resting
in the darker soil. Through intense investigations with the
spectrometers, scientists determined the blueberries are rich in
the mineral hematite. On Earth, hematite often forms in the
presence of liquid water. These blueberries helped scientists
determine that the rocks at Eagle Crater had been soaked in
water.
March 26, 2004 - This image from
Opportunity's panoramic camera is an
approximate true-color rendering of the
rock called the “Berry Bowl” in the Eagle
Crater outcrop. The study of this
“blueberry-strewn” area and the
identification of hematite as the major ironbearing element within these sphere-like
grains helped scientists confirm their
hypothesis that the hematite in these
Martian spherules was deposited in water.
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Opportunity Finds More Evidence of Martian Water
March, 2004 - This image taken by the
Opportunity panoramic camera shows the
rock called “El Capitan,” just right of
center, in the upper portion of the outcrop
in “Eagle Crater.” El Capitan was a
significant find because it provided clues
to lead scientists to believe the entire
outcrop in Eagle Crater was once covered
in water.
This image shows fine, parallel lamination
in the upper area of the rock, that also
contains scattered sphere-shaped objects
ranging from 0.04 to 0.24 inches in size.
There are also more abundant, scattered
vugs, or small cavities, that are shaped
like discs. These are about 0.4 inches
long. The rover's Miniature Thermal
Emission Spectrometer uses infrared
detectors to determine the mineral
composition of rocks and soil. The
spectrometer showed that “El Capitan”
contains a considerable amount of sulfate.
The Mössbauer Spectrometer identified
the mineral jarosite, which contains water
in the form of hydroxyl.
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Opportunity Finds Evidence of a Martian Sea
March 23, 2004 - A magnified view of the rock “Upper Dells” provides evidence that
Opportunity sits on the shoreline of what was once a salty sea on Mars. Rippled patterns in
the rocks at Meridiani Planum suggest the land was once a salt flat, sometimes covered by
shallow water and sometimes dry. Telltale patterns called crossbedding and festooning, in
which some layers within a rock lie at angles to the main layers, led scientists to the
conclusion that the rippled shapes formed under a current of water and not wind.
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Opportunity’s First Look at Endurance Crater
May 6, 2004 - This approximate true-color mosaic taken by the Opportunity panoramic camera
shows the impact crater “Endurance.” The crater is about 430 feet in diameter and more than 66
feet deep. Scientists were eager to explore Endurance for clues to Mar's geological history. The
crater's exposed walls provided a window to what lies beneath the surface and what geologic
processes occurred in the past. The challenge was getting to the scientific targets; most of the
crater's rocks are embedded in vertical cliffs. The rover spent six months studying Endurance
including descending into the crater and successfully climbing out.
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Opportunity Views “RAT” Hole Trail
July 19, 2004 - This view from the rover’s
panoramic camera is a false-color
composite rendering of the first seven
holes that the Rock Abrasion Tool (RAT)
drilled on the inner slope of “Endurance
Crater.” The rover was about 39 feet down
into the crater when it acquired the images
combined into this mosaic. The view is
looking back toward the rim of the crater,
with the rover's tracks visible. The tailings
around the 1.8 inch diameter holes drilled
by the RAT show evidence of fine-grained
red hematite similar to what was observed
months earlier in “Eagle Crater” outcrop
holes.
Viewers find it far easier to see the seven
holes in this exaggerated color image than
in true color; the same is true for scientists
who are studying the holes on Earth.
Starting from the uppermost pictured
(closest to the crater rim) to the lowest, the
rock abrasion tool hole targets are called
“Tennessee,” “Cobblehill,” “Virginia,”
“London,” “Grindstone,” “Kettlestone,” and
“Drammensfjorden.”
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Opportunity Views Burns Cliff in Endurance Crater
November 13 to 20, 2004 - Opportunity views “Burns Cliff” after driving to the base of this
southeastern portion of the inner wall of “Endurance Crater.” The wide-angle view makes the cliff
walls appear to bulge out toward the camera. In reality the walls form a gently curving, continuous
surface.
Scientists analyzed data from stacked sedimentary rock layers 23 feet thick that were exposed
inside Endurance Crater, identifying three divisions within the stack. The lowest, oldest portion had
the signature of dry sand dunes. The middle portion had an environment of windblown sheets of
sand with all the particles produced in part by previous evaporation of liquid water. The upper
portion corresponded to layers Opportunity had found inside a smaller crater near its landing site.
Scientists found that the materials in all three divisions were wet both before and after the layers
were deposited by either wind or water.
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Opportunity Investigates its Heatshield Impact Site
December 28, 2004 - This mosaic was acquired shortly after Opportunity arrived at the site where
its heatshield hit the ground south of “Endurance Crater” on January 24, 2004. The heatshield
was part of the aeroshell supplied by Lockheed Martin in Denver, CO.
The mosaic of images taken by the panoramic camera are approximate true-color. On the left, the
main heatshield piece is inverted and reveals its metallic insulation layer, glinting in the sunlight.
The main piece stands about 3.3 feet high and lies about 43 feet from the rover. The other large,
flat piece of debris near the center of the image is about 46 feet away. The circular feature on the
right side of the image is the crater made by the heatshield's impact. It is about 9.2 feet in
diameter but only 2 to 4 inches deep. The crater is about 20 feet from Opportunity in this view.
Smaller fragments and debris can be seen all around the impact site.
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Opportunity Stuck at Meridiani in Sand Dune
May 6 to May 14, 2005 - This panoramic image was acquired by Opportunity on the plains of
Meridiani about 1.2 miles south of “Endurance Crater.” The rover was stuck in the dune's deep fine
sand for more than a month at a place known informally as “Purgatory Dune.”
Opportunity's tracks leading back to the north (center of the panorama) are a reminder of the
rover's long trek from Endurance Crater. The deep ruts dug by Opportunity’s wheels as it became
stuck in the sand appear in the foreground. The crest and trough of the last ripple the rover
crossed before getting stuck is visible in the center. These wind-formed sand features are about 4
to 6 inches tall. The crest of the actual ripple where the rover got stuck can be seen just to the right
of center. The tracks and a few other places on and near ripple crests are dustier than the
undisturbed or “normal” plains soils in Meridiani. Since the time these ruts were made, some of the
dust has been blown away by the wind, reaffirming the dynamic nature of the Martian environment,
even in this barren, ocean-like desert of sand.
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Opportunity on the Rim of Erebus
Nov. 23 to Dec. 5, 2005 - This is the “Erebus Rim” panorama, acquired by the Opportunity
panoramic camera while exploring sand dunes and outcrop rocks in Meridiani Planum. Since the
time this panorama was acquired, engineers diagnosed and tested Opportunity's robotic arm, and
the panorama has been expanded to include more images of this terrain. The panorama is an
approximate true-color rendering, and the largest acquired by either rover during the mission. This
image provides the highest resolution view yet of the finely-layered outcrop rocks, wind ripples,
and small cobbles and grains along the rim of the 984 feet wide but shallow “Erebus” crater. Once
the arm diagnostics and testing were completed, Opportunity started to explore other layered
outcrop rocks at Erebus and eventually continued southward toward the large crater known as
“Victoria.”
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Reference Information
End
Images:
Courtesy of NASA/JPL-Caltech, Cornell University and noted
Text:
Roving Mars, Steven W. Squyres, Hyperion, New York, NY, 2005
http://mars.jpl.nasa.gov/
http://marsrovers.jpl.nasa.gov/home/index.html
http://en.wikipedia.org/wiki/Mars_Exploration_Rover_Mission
http://www.space.com/bestimg/
http://www-b.jpl.nasa.gov/
http://nssdc.gsfc.nasa.gov/planetary/
http://www.nasa.gov/
http://photojournal.jpl.nasa.gov/
http://www.spaceflightnow.com/delta/d307/040728slc17.html
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MER-A Stack-up
 Boeing Delta II was selected for the MER missions because it had the right liftoff
capability for the weight requirements and it is extremely reliable.
 MER-A with the Spirit rover used a standard Delta II 7925.
 MER-B with the Opportunity rover used a Delta II 7925H (H for “Heavy”) because it needed
more energy since Earth was further from Mars when it was launched.
 Delta II family of launch vehicles had been in service for over 10 years and had
successfully launched 90 projects including the last five NASA missions to Mars:
 Mars
 Mars
 Mars
 Mars
 Mars
Global Surveyor in 1996
Pathfinder in 1996
Climate Orbiter in 1998
Polar Lander in 1999
Odyssey in 2001
 Launch Vehicle elements:
 Stage I - fuel and oxygen tanks that feed an engine for ascent.
 Solid Rocket Motors - six strap-on, solid-fuel boosters are ignited at liftoff to increase thrust
and three boosters are used after a minute into the flight. MER-B was launched using a Delta
II 7925H with larger solid rocket motors than the MER-A.
 Payload Fairing - thin metal shroud or nose cone to protect the spacecraft during the ascent
through Earth's atmosphere.
 Stage II - fuel and oxidizer and the vehicle's “brains” fire twice, once to insert the vehiclespacecraft stack into low Earth orbit and then again to orient the third stage prior to it firing.
 Stage III - solid rocket motor provides the majority of the velocity change needed to leave
Earth orbit and inject the spacecraft on a trajectory to Mars; connected to the spacecraft until
done firing, then separates.
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MER-A Stack-up (Continued)
 Launch Vehicle Complex 17 (SLC-17)
 MER spacecrafts launched from SLC-17 (pronounced “slick”) pads A and B at Cape
Canaveral Air Force Station, FL.
 Initial construction of SLC-17 began in April 1956 and supported its first launch in January
1957.
 SLC-17 was modified to support the first Delta II launch on February 14, 1989.
 MER spacecraft is separate from the launch vehicle. It is the protective
“spaceship” that enables the precise cargo (the rover) to travel between Earth and
Mars once the launch vehicle has projected it outside of Earth´s atmosphere and
gravity pull.
 Spacecraft includes the mechanical units that safely carry and maneuver the rover as it
enters the Martian atmosphere and lands on Mars.
 Once on the surface, it lowers a ramp to let the rover drive off.
 The MER spacecraft consists of:
 Cruise Stage - configuration for travel between Earth & Mars.
 Entry, Descent, & Landing System - configuration for entry into the Martian atmosphere.
Includes the aeroshell (the heatshield and backshell), the parachute, the airbags, and a lander
structure.
 Rover - six wheeled vehicle, the size of a golf cart, with science instruments for discoveries
on the Martian surface.
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MER Rover
 MER spacecraft surface operations:
 After the MER spacecraft entered and descended through the Martian atmosphere, the airbagprotected lander settled onto the surface and opened.
 The rover drove off the landing craft.
 Images were taken to give scientists information to select promising geological targets.
 Primary rover science instruments:
 Panoramic Camera (Pancam) - determines the mineralogy, texture, and structure of the local
terrain.
 Miniature Thermal Emission Spectrometer (Mini-TES) - identifies promising rocks and soils for
closer examination and for determining the processes that formed Martian rocks. The instrument
will also look skyward to provide temperature profiles of the Martian atmosphere.
 Alpha Particle X-Ray Spectrometer (APXS) - used for close-up analysis of the abundances of
elements that make up rocks and soils.
 Mössbauer Spectrometer (MB) - used for close-up investigations of the mineralogy of ironbearing rocks and soils.
Microscopic Imager (MI) - obtains close-up, high-resolution images of rocks and soils.
 Rock Abrasion Tool (RAT) - removes dusty and weathered rock surfaces and exposes fresh
material for examination by instruments onboard.
 Magnets - collects magnetic dust particles. The MB and the AXPS analyze the particles collected
and help determine the ratio of magnetic particles to non-magnetic particles. They also analyze the
composition of magnetic minerals in airborne dust and rocks that have been ground by the RAT.
 Instrument Deployment Device (IDD) - robotic arm with the APXS, MB, MI and RAT located on
the end.
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Spirit Two Earth Year Timeline
 June 10, 2003 - MER-A with Spirit launched from Cape Canaveral, FL.
 January 3, 2004 - Spirit lands in Gusev Crater.
 The landing site is located at a possible former lake in a giant impact crater.
 In the week following Spirit's landing, NASA's website recorded 1.7 billion hits and 34.6 terabytes
of data transferred eclipsing records set by previous NASA missions.
 January 21, 2004 - Deep Space Network loses contact with Spirit.
 Spirit was unable to perform science operations for 10 days while engineers updated its software
and ran tests. The problem was corrected by reformatting Spirit's flash memory and upgrading the
software to avoid memory overload. Spirit returned to full scientific operations by February 5.
 March 5, 2004 - NASA announced Spirit had found hints of water history on Mars in a
rock dubbed “Humphrey.”
 March 11, 2004 - Spirit reaches Bonneville crater after a 400 yard journey.
 September 22, 2004 - NASA announced Spirit would attempt to climb to the top of
the Columbia Hills.
 Columbia Hills are older than the plains and may provide better insight into the past environment
of Gustev Crater.
 December 13, 2004 - Scientists identified a water-signature mineral called goethite in
bedrock that Spirit examined in the Columbia Hills.
 One of the mission's surest indicators yet for a wet history on Spirit's side of Mars.
 December 20, 2004 – Spirit logs 2.5 miles on Mars.
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Spirit Two Earth Year Timeline (Continued)
 January 3, 2005 - Spirit celebrates 1 Earth year on Mars.
 March 15, 2005 - High winds remove dust from Spirit’s solar panels.
 Solar panels improved performance causes the rover’s power supply to double.
 April 6, 2005 - NASA announces Spirit will climb a rocky slope toward the top of
Husband Hill in the Columbia Hills.
 June 11, 2005 - Spirit arrives at the base of Columbia Hills after 2 month drive.
 August 21, 2005 - Spirit reaches the summit of Husband Hill after a drive of 3 miles
from landing site.
 October 16, 2005 - Spirit starts descent from Husband Hill Summit to “Home Plate.”
 November 20, 2005 - Spirit marks one Martian year (687 Earth days) on Mars.
 Spirit has returned over 70,000 images and traveled over three miles.
 Scientists have studied the composition and texture of six different rock types encountered by
Spirit. The rocks indicate Spirit is in an area that was once a hot, violent place with volcanic
explosions and impacts.
 January 3, 2006 - Spirit celebrates 2 Earth years on Mars.
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Opportunity Two Earth Year Timeline
 July 7, 2003 - MER-B with Opportunity launched from Cape Canaveral, FL.
 January 25, 2004 - Opportunity landed in Eagle Crater at Meridiani Planum.
 Meridiani Planum, located on the opposite side of Mars from Spirit, is where mineral deposits
(hematite) suggest Mars had a wet past.
 March 23, 2004 - NASA news conference announced “major discoveries” in the
search for hints of past liquid water on the Martian surface.
 A delegation of the MER science team showed pictures and data revealing a stratification pattern
and cross bedding within the rocks in the outcrop inside Eagle Crater suggesting a history of
flowing water in the region. The irregular distribution of chlorine and bromine also suggests the
rover sat in a place that once had been the shoreline of a salty sea, now evaporated.
 April 30, 2004 - Opportunity arrived at Endurance Crater.
 June 4, 2004 – NASA announced Opportunity will descend into Endurance Crater.
 Potential science value gained by sending the rover into the crater outweighed the risk of not
being able to get the rover back.
 June 8, 2004 - Opportunity drives into Endurance Crater.
 Opportunity moves forward enough to just get all six wheels into the crater.
 Rover enters crater in search of clues to an earlier history of water than those found at Eagle
Crater where rover landed.
 During the final rock investigation inside the crater, scientists conclude that Endurance was most
likely a salt flat, alternately wet and dry, rather than a deep-water environment.
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Opportunity Two Earth Year Timeline (Continued)
 September 22, 2004 - NASA announced Opportunity would leave Endurance Crater,
visit its discarded heat shield, and proceed to Victoria Crater.
 Opportunity examines bedrock along the route between Endurance and Victoria craters. The
texture of the bedrock on the way to Victoria is similar to the bottom layer of Endurance Crater
suggesting a cyclical change in the environment.
 November 11, 2004 - Opportunity starts to leave Endurance Crater by retracing its
entry path.
 January 19, 2005 - Opportunity finds meteorite near its heat shield.
 First meteorite identified on another solar system body - none were found on the Moon.
 Composed of iron and nickel, the pitted, basketball-sized rock landed on Mars.
 Meteorite that blasted Meteor Crater near Winslow, Arizona is similar in composition.
 January 25, 2005 - Opportunity celebrates 1 Earth year on Mars.
 April 6, 2005 - NASA announced Opportunity would visit the “Etched Terrain.”
 June 4, 2005 - Opportunity escapes from a sand dune where it had been stuck since
April 26.
 December 12, 2005 - Opportunity marks one Martian year (687 Earth days) on Mars.
 Opportunity has returned over 58,000 images and traveled over four miles.
 Both rovers have lasted over seven times their original life expectancy. Spirit and Opportunity
were not expected to survive much longer than ninety days.
 January 25, 2006 - Opportunity celebrates 2 Earth years on Mars.
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