[meteorite-list] Prolific Mars Orbiter Completes 50, 000 Orbits (MRO)
From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 4 Apr 2017 16:55:23 -0700 (PDT)
Prolific Mars Orbiter Completes 50,000 Orbits
Jet Propulsion Laboratory
March 29, 2017
The most data-productive spacecraft yet at Mars swept past its 50,000th
orbit this week, continuing to compile the most sharp-eyed global coverage
ever accomplished by a camera at the Red Planet.
In addition, the spacecraft -- NASA's Mars Reconnaissance Orbiter (MRO)
-- recently aided preparations for NASA's next mission to Mars, the InSight
lander. Insight will launch next year on a mission to study the planet's
deep interior. Meanwhile, the orbiter continues diverse science observations
of Mars and communications-relay service for two active Mars rovers, Curiosity
MRO's Context Camera (CTX) exploits a sweet spot in the balance between
resolution and image file size. With a resolution of about 20 feet (6
meters) per pixel in images of the Martian surface, it has provided a
library of images now covering 99.1 percent of Mars. That is approximately
equivalent to the land area of Earth. No other camera ever sent to Mars
has photographed so much of the planet in such high resolution.
The Context Camera has taken about 90,000 images since the spacecraft
began examining Mars from orbit in late 2006. Each one reveals shapes
of features down to sizes smaller than a tennis court, in a swath of ground
about 18.6 miles (30 kilometers) wide.
"Reaching 99.1-percent coverage has been tricky because a number of factors,
including weather conditions, coordination with other instruments, downlink
limitations, and orbital constraints, tend to limit where we can image
and when," said Context Camera Team Leader Michael Malin of Malin Space
Science Systems, San Diego.
In addition to observing nearly the entire planet at least once, the Context
Camera has observed 60.4 percent of the planet more than once. These observations
aid science directly and also certify the safety of future landing sites.
Malin said, "Single coverage provides a baseline we can use for comparison
with future observations, as we look for changes. Re-imaging areas serves
two functions: looking for changes and acquiring stereoscopic views from
which we can make topographic maps."
A dramatic type of change the Context Camera has documented more than
200 times is a fresh impact crater appearing between the times of two
observations. These images enabled scientists to calculate the rate at
which small asteroids, or bits of comets, are colliding with Mars. Some
of the fresh impacts reveal white material interpreted as water ice. The
latitudes and estimated depths of the ice-exposing craters provide evidence
about the distribution of buried ice near the surface. MRO's Shallow Radar
has found ice farther underground, but this very shallow ice would go
undetected if not for its exposure by impacts.
One of MRO's other cameras, the High Resolution Imaging Science Experiment
(HiRISE), can zoom in on the new impact craters found by the Context Camera.
For some of these craters, HiRISE and MRO's Compact Reconnaissance Imaging
Spectrometer for Mars have confirmed the presence of water ice. However,
even though MRO has returned more than 300 terabits of science data, the
much higher spatial resolution of HiRISE has limited its coverage of Mars'
surface to about three percent. A third MRO camera, the Mars Color Imager,
observes almost the entire planet every day to track weather change. Another
instrument, the Mars Climate Sounder, records vertical profiles of the
atmosphere's temperatures and suspended particles.
The spacecraft was launched Aug. 12, 2005. It entered an elongated orbit
of Mars in March 2006, then spent several months using friction with Mars'
upper atmosphere to revise its orbit. Since beginning its science operations
in November 2006, MRO has been flying near-polar orbits lasting about
two hours, at altitudes from 155 to 196 miles (250 to 316 kilometers).
The mission completed its 50,000th orbit on Monday, March 27.
"After 11 and a half years in flight, the spacecraft is healthy and remains
fully functional," said MRO Project Manager Dan Johnston at NASA's Jet
Propulsion Laboratory, Pasadena, California. "It's a marvelous vehicle
that we expect will serve the Mars Exploration Program and Mars science
for many more years to come."
On March 22, the mission made the latest adjustment to the orbit, with
a 45.1-second burn of six intermediate-size rocket engines, each of which
provides 5 pounds (22 newtons) of thrust. This maneuver revised the orbit
orientation, so that the spacecraft can be at the right place at the right
time, on Nov. 26, 2018, to receive critical radio transmissions from NASA's
InSight Mars lander as it descends to the surface.
MRO has already provided more than 60 images from HiRISE for advance analysis
of the landing region for InSight. In a broad plain of the Elysium Planitia
region of equatorial Mars, InSight will use a seismometer and heat probe
to examine the interior of Mars to better understand the formation process
of rocky planets like Earth. The final MRO image for assessment of this
landing area will be taken Thursday, March 30.
For additional information about Mars Reconnaissance Orbiter, visit:
For additional information about InSight, visit:
News Media Contact
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster at jpl.nasa.gov
Laurie Cantillo / Dwayne Brown
NASA Headquarters, Washington
202-358-1077 / 202-358-1726
laura.l.cantillo at nasa.gov / dwayne.c.brown at nasa.gov
Received on Tue 04 Apr 2017 07:55:23 PM PDT