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NASA's MAVEN Shrinking Its Orbit for Mars 2020 Rover



NASA's 4-year-old atmosphere-sniffing Mars
Atmosphere and Volatile Evolution (MAVEN) mission is embarking on a new
campaign today to tighten its orbit around Mars. The operation will reduce the
highest point of the MAVEN spacecraft's elliptical orbit from 3,850 to 2,800
miles (6,200 to 4,500 kilometers) above the surface and prepare it to take on
additional responsibility as a data-relay satellite for NASA's Mars 2020 rover,
which launches next year.

"The MAVEN spacecraft has done a phenomenal
job teaching us how Mars lost its atmosphere and providing other important
scientific insights on the evolution of the Martian climate, "said Jim
Watzin, director of NASA's Mars Exploration Program. "Now we're recruiting
it to help NASA communicate with our forthcoming Mars rover and its successors. "

While MAVEN's new orbit will not be drastically
shorter than its present orbit, even this small change will significantly
improve its communications capabilities. "It's like using your cell phone,"
said Bruce Jakosky MAVEN principal investigator from the University of Colorado, Boulder. "The
closer you are to a cell tower, the stronger your signal. "

A strong telecommunications antenna signal is
not the only benefit of a tighter orbit. Coming in nearly 1

,000 miles (about
1,500 kilometers) closer also will allow the MAVEN orbiter to circle Mars more
frequently – 6.8 orbits per Earth day versus 5.3 previously – and thus
communicate with the Mars rovers more frequently. While not conducting relay
communications, MAVEN will continue to study the structure and composition of
the upper atmosphere of Mars. "We're planning a vigorous science mission
far into the future, "Jakosky said.

The MAVEN mission was designed to last two years
in space, but the spacecraft is still operating normally. With the mission
managing its fuel to last through 2030, NASA plans to use MAVEN's relay
capability as long as possible. The MAVEN carries an ultra-high-frequency carrier
radio transceiver – similar to transceivers carried on other Mars orbiters – that
allows it to relay data between Earth and rovers or landers on Mars. The MAVEN
Spacecraft has already served occasionally as NASA's communication liaison with
the Curiosity rover.

Over the next few months, MAVEN engineers will
use a navigation technique known as aerobraking – like applying the brakes on a
car – to take advantage of the drag of the Red Planet's upper atmosphere to
slow the spacecraft down gradually, orbit by orbit. This is the same drag you
would feel if you put your hand out of the window of a moving car.

Based on the tracking of the spacecraft by the navigation team at
NASA's Jet Propulsion Laboratory in Pasadena, California, and at Lockheed
Martin in Littleton, Colorado, engineers will begin carefully lowering the
lowest part of the spacecraft's orbit into the Martian upper atmosphere over
the next couple of days by firing its thrusters. The spacecraft will circle
Mars at this lower altitude about 360 times over the next 2.5 months, slowing
down slightly with each pass through the atmosphere. While it may seem like a
time-consuming process, aerobraking is the most efficient way to change the
spacecraft's trajectory, said Jakosky: "The effect is the same as if we
Fired our thrusters a little bit on every orbit, but this way, we use very
little fuel. "

Fortunately, the team has ample experience operating the
spacecraft at these lower altitudes. On nine previous occasions throughout the
mission, MAVEN engineers have dipped the orbiter into the same altitude targets
for aerobraking to take measurements of the Martian atmosphere. As a result of
these "deep dips" and other measurements, NASA has learned that solar
wind and radiation had stripped Mars of most of its atmosphere, changing the planet's
early climate from warm and wet to the dry environment we see today. MAVEN too
discovered two new types of auroras on Mars and the presence of charged metal atoms in its upper atmosphere that tell us that a lot of debris is hitting Mars that may affect
its climate.

MAVEN's principal investigator is based at the University of
Colorado's Laboratory for Atmospheric and Space Physics, Boulder. The
university provided two science instruments and leads science operations, as
well as education and public outreach, for the mission. NASA's Goddard Space
Flight Center in Greenbelt, Maryland, manages the MAVEN project and provided
two science instruments for the mission. Lockheed Martin built the spacecraft
and is responsible for mission operations. The University of California at
Berkeley's Space Sciences Laboratory also provided four science instruments for
the mission. NASA's Jet Propulsion Laboratory in Pasadena, California, provides
navigation and Deep Space Network support, as well as the Electra
telecommunications relay hardware and operations.

For more information on the
MAVEN mission, visit:

https://www.nasa.gov/maven or
http://lasp.colorado.edu/home/maven/

For more information on the
Mars 2020 mission, visit:

https://mars.nasa.gov/mars2020/

News Media Contact

Nancy Jones
NASA's Goddard Space Flight Center, Greenbelt, Md.
301-286-0039
nancy.n.jones@nasa.gov

DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle@jpl.nasa.gov

Story by:
Lonnie Shekhtman
NASA's Goddard Space Flight Center

2019-020


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