Sky and Telescope - July 2018 - 20
Red Planet Resolution
Region of interaction
with solar wind
on ballistic trajectories
and do not collide
with one another
Temperature controlled by
absorption of UV sunlight
Atmosphere not well mixed: diffusion
causes atoms to separate out by mass
Temperature controlled by
Atmosphere well mixed,
"most common" behavior of the modern atmosphere is. This
means that the extrapolation of present-day loss rates into
the past carries some uncertainty.
The spacecraft and all of its science instruments continue
to operate nominally (a wonderful word to hear for anybody involved in the spacecraft world!). We plan to continue
q GLOBAL STORM A dust storm enveloped the Red Planet with the
onset of southern hemisphere spring in 2001, shown here just before
(left) and two months after the storm began. Airborne dust absorbs sunlight and warms the atmosphere, enabling water vapor to rise to higher
altitudes and escape to space.
observations in coordination with the European Mars Express
mission, which has been in orbit for more than a decade.
And we'll coordinate with future observations from other
spacecraft: The European/Russian Trace Gas Orbiter has
ﬁnally settled into its circular, near-polar orbit at Mars and is
beginning science observations, and the United Arab Emirates
Hope orbiter will launch in 2020 to study how the lower and
upper atmosphere connect (S&T: Nov. 2017, p. 14).
MAVEN's current extended mission runs through September 2018, but it has enough fuel that we think it can
survive until 2030. We plan to continue our science observations as long as possible, along with serving as a communications relay between Earth and rovers and landers on the
Martian surface. It's our hope that, in addition to what we've
already learned from MAVEN, teaming it up with current
and future spacecraft will teach us even more about Mars's
atmosphere and the history of habitability on this small,
¢ Planetary scientist and MAVEN Principal Investigator
June 26, 2001
J U LY 2 0 1 8 * S K Y & T E L E S C O P E
September 4, 2001
BRUCE JAKOSKY is Associate Director of the Laboratory for
Atmospheric and Space Physics at the University of Colorado,
Boulder. He has been exploring Mars since the Viking missions
in the 1970s.
AT M OSPHERE ILLUSTR ATIONS: G REGG DINDER M A N / S&T, SOURCE: AU THOR; DUST STOR M: N ASA /
J. BELL (COR NELL UNIV.) / M. WOLFF (SSI) / HUBBLE HERITAG E TE A M (STSCI / AUR A)
p MARS'S ATMOSPHERE Temperatures in the Martian atmosphere decline steadily with height for the first 100 km or so - unlike on Earth, where
the temperature decreases, then increases, then decreases again (in part due to the ozone layer, which creates rising temperatures in the stratosphere). Above both worlds' lower atmospheres, temperatures rise steadily due to absorbed sunlight (thermosphere) and the solar wind (exosphere).