[meteorite-list] MAVEN Begins Science Mission at Mars

[Ron Baalke]

http://spaceflightnow.com/2014/11/18/maven-begins-science-mission-at-mars/

MAVEN begins science mission at Mars
by Stephen Clark
Spaceflight Now
November 18, 2014

NASA's newest Mars orbiter has formally started a one-year research campaign 
to study an ancient case of climate change that starved the red planet 
of water, breathable air and potential life, scientists said Monday.

The mission's milestone came after two months of instrument calibrations, 
test observations and trajectory adjustment maneuvers to lower the MAVEN 
spacecraft's altitude after it arrived in Mars orbit Sept. 21.

"With the formal start of our science mission, we're on track to be able 
to carry out our full mission as planned, and the science team is looking 
forward to an incredibly exciting year," wrote Bruce Jakosky, the mission's 
chief scientist from the University of Colorado at Boulder's Laboratory 
for Atmospheric and Space Physics.

The $671 million Mars Atmosphere and Volatile Evolution, or MAVEN, mission 
launched Nov. 18, 2013, to kick off a 10-month cruise to the red planet.

The robotic probe is fitted with nine scientific instruments to sniff 
the wispy air at the top of the Martian atmosphere, collecting data researchers 
will use to look back in time and figure out how Mars transformed from 
a habitable world to a barren planet void of any detectable life.

Since MAVEN arrived at Mars two months ago, ground controllers moved the 
orbiter closer to the red planet through a series of rocket firings. After 
initially entering an orbit arcing nearly 30,000 miles (44,500 kilometers) 
from Mars, MAVEN is now circling the red planet at altitudes between 93 
miles and about 3,700 miles (150 kilometers to 6,000 kilometers).

A chance encounter between Mars and a comet was also an early focus for 
MAVEN. The spacecraft monitored the Martian atmosphere's reaction as comet 
C/2013 A1 - also known as Siding Spring - passed within 87,000 miles of 
the red planet, a near-miss in cosmic terms.

A fleet of NASA, European and Indian orbiters and rovers joined MAVEN 
to gather "bonus science" during the cometary flyby.

MAVEN saw changes as the comet's dust cloud hit the upper atmosphere of 
Mars, with one of the craft's spectrometers seeing a rise in eight different 
types of metals, including magnesium and iron. The mission collected the 
first data on the composition of dust streaming away from a comet from 
the Oort Cloud, a distant ring of tiny icy worlds beyond the planets that 
are believed to be leftovers from the solar system's formation, according 
to NASA.

An imaging spectrograph on MAVEN measured a spike in ultraviolet emissions 
high in the Martian atmosphere during the comet flyby, then saw levels 
return to normal several days later.

MAVEN's observations "revealed a tremendous quantity of metal ions that 
came from cometary dust that entered the atmosphere," Jakosky wrote. "Their 
presence was unexpected, in that the nominal models of the paths taken 
by dust grains, calculated prior to the comet passage, indicated that 
no dust would make it all the way to Mars."

Like NASA's other Mars orbiters, MAVEN ducked behind the red planet during 
the comet's closest approach to shield the spacecraft from dust grains 
that could have damaged or destroyed the probes in high-velocity impacts.

"From the observations made both during the cruise to Mars and during 
the transition phase, we know that our instruments are working well," 
Jakosky wrote. "The spacecraft also is operating smoothly, with very few 
'hiccups' so far."

The mission mission now turns to its primary purpose of investigating 
an ancient shift in Martian climate that dried up riverbeds, thinned out 
the red planet's atmosphere, and may have doomed Martian life - if it 
existed.

"The evidence shows that the Mars atmosphere today is a cold, dry environment, 
one where liquid water really can't exist in a stable state," Jakosky 
said in a September press briefing. "But it also tells us when we look 
at older surfaces that the ancient surfaces had liquid water flowing over 
it, and we see evidence for lakes - for river channels - a lot of evidence 
of liquid water that required a very different climate than the one we 
have today."

Data from previous missions lack insight into how and when Mars changed, 
and MAVEN's job is to find out what triggered the dramatic climate shift.

Five times during its one-year prime mission, MAVEN will alter its orbit 
to dip deeper into the wispy layers of gas enshrouding Mars, plowing through 
the atmosphere just 77 miles above the red planet.

The spacecraft is outfitted with instrumentation to keep track of solar 
activity, measure the make-up of the Martian upper atmosphere, and observe 
how the atmosphere moves, grows and shrinks during the mission.

NASA has committed to paying for MAVEN to collect scientific data for 
at least one year - until late 2015 - but the platform has enough fuel 
to last up to a decade.

One of MAVEN's ancillary objectives is to serve as a communications relay 
platform for NASA's rovers on the surface of Mars. The space agency relies 
on orbiters above Mars to function as faster radio links with the rovers 
than if engineers were forced to communicate with them directly.

Engineers tested MAVEN's relay radio Nov. 6 in a linkup with the Curiosity 
rover. Research is the reason for MAVEN's existence, but NASA may use 
the orbiter as a communications conduit more often beginning in 2016.