As InSight lander nears end, NASA details meteorite strike on Mars
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[October 28, 2022]
By Will Dunham
WASHINGTON (Reuters) -The InSight lander,
perched on the surface of Mars since 2018, will run out of power and
stop operations within four to eight weeks, NASA said on Thursday, even
as scientists detailed a big meteorite strike it detected that gouged
boulder-sized chunks of ice surprisingly close to the planet's equator.
Dust has been accumulating on solar panels that draw power for the U.S.
space agency's stationary lander, exacerbated by a dust storm, and has
been depleting its batteries, planetary geophysicist Bruce Banerdt of
NASA's Jet Propulsion Laboratory, InSight mission's principal
investigator, told a briefing.
InSight's mission, which has helped reveal the internal structure of
Mars and its seismic activity, originally was planned for two years but
was extended to four. When the power runs out, NASA will lose contact
with InSight, Banerdt said.
"InSight has been successful beyond my expectations," Banerdt told
Reuters. "We have determined the thickness of the crust, the size and
density of the core, and details of the structure of the mantle. For the
first time we have a detailed global map of the deep interior of another
planet - other than the Earth and moon."
InSight also established that Mars is seismically active, detecting
1,318 marsquakes.
Two research papers published in the journal Science detailed meteorite
strikes on the Martian surface detected by InSight in September and
December of last year. Seismic waves triggered by the impacts revealed
fresh details about the structure of the Martian crust, the planet's
outer layer.
"What an awesome capstone science result to end on - literally going out
with a bang," Lori Glaze, director of NASA's Planetary Science Division,
told reporters.
Of particular interest was a space rock with a diameter estimated at
16-39 feet (5-12 meters) that crashed last Dec. 24 in a region called
Amazonis Planitia, carving a crater about 490 feet (150 meters) wide and
70 feet (21 meters) deep.
It caused a magnitude 4 quake detected by InSight's seismometer
instrument, while cameras aboard the Mars Reconnaissance Orbiter
observed the crater from space. Boulder-sized blocks of ice were seen
strewn around the crater's rim.
Objects that large enter Earth's atmosphere about once a year but
generally burn up in our planet's thicker atmosphere.
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A life-size model of the spaceship
Insight, NASA's first robotic lander dedicated to studying the deep
interior of Mars, is shown at Jet Propulsion Laboratory (JPL) in
Pasadena, California, U.S. November 26, 2018. REUTERS/Mike Blake/
"A whole lot of water ice was exposed by this impact," Brown
University planetary scientist Ingrid Daubar, part of the InSight
science team, told the briefing. "This was surprising because this
is the warmest spot on Mars, the closest to the equator we've ever
seen water ice."
Glaze said that while ice is known to exist near the Martian poles
future human exploration missions would aim to put astronauts as
close to the equator as possible for warmer conditions. Ice near the
equator could provide resources such as drinking water and rocket
propellant.
"Having access to ice at these lower latitudes, that ice could be
converted into water, oxygen or hydrogen - that could be really
useful," Glaze said.
The September 2021 crater also was large, about 425 feet (130
meters) wide. The two were the largest impacts detected by InSight
since arriving on Mars.
InSight for the first time detected seismic waves traveling like
ripples on water along the Martian surface, as opposed to deeper in
the planet's body. The reverberation from the two impacts gave clues
about the crust over a wide geographical expanse in the northern
hemisphere.
The three-legged InSight sits in a vast and relatively flat plain
called Elysium Planitia, just north of the equator. Until now,
InSight had obtained data on the structure of the Martian crust,
consisting mostly of fine-grained volcanic basalt rock, only in the
area beneath its landing site.
The crust at the landing site was composed of relatively soft
material, less dense rock. This was not the case for the other
regions covered by the new data, where the crust appears denser.
"As a consequence of our analysis of surface waves, we now
understand that the crust of Mars north of the equatorial dichotomy
- a conspicuous feature seen from the topographic variation on Mars
that divides the southern highlands and northern lowlands - has a
relatively uniform structure," said seismologist Doyeon Kim of the
Institute of Geophysics at ETH Zurich, lead author of one of the
studies.
(Reporting by Will Dunham; Additional reporting by Steve Gorman;
Editing by Rosalba O'Brien)
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