[meteorite-list] Mars Reconnaissance Orbiter Nears End ofAerobraking

From: MexicoDoug <MexicoDoug_at_meteoritecentral.com>
Date: Mon Aug 28 20:36:51 2006
Message-ID: <01b501c6cb03$03a01100$d6cf5ec8_at_0019110394>

Excerpt from Ron's MRO newsrelease:

> http://mars.jpl.nasa.gov/mro/newsroom/pressreleases/20060825a.html
> On each of the aerobraking passes, the spacecraft records the density of
> the atmosphere on both the inbound and outbound legs as it flies through
> its closest approach to the planet. This information is used to
> characterize atmospheric variability, which helps guide the flight team
> to design the right maneuvers. The data will also be analyzed to
> understand the structure and circulation of the upper atmosphere.

Dear List:
What an understatement! Reading this, it hit me how far in the future we've
arrived. The instrument is a result of a fine pedigree of prior devices
empowering the Mars Reconnaissance Orbiter (MRO) to calculate the "density"
of the atmosphere while getting a hot-foot. It is called something like the
z-axis frictional drag accelerometer. I'm not sure if z is the axis of the
spacecraft velocity (direction of travel) or the height above the Martian
surface, but that is academic.

What seems true is that this absolutely awesome science and engineering
package doesn't just tell JPL navigators the atmosphere's local density as
it skids in - but also has a detector of sorts that collects data which will
teach us the density, composition and variations of the Martian atmosphere
in a column from 200 km down to the surface? The little meteorite man
inside of me can't help thinking how this sounds like may help out
understanding of meteorite survivability after atmospheric entry. While the
experiment toots a list of impressive studies in the above 100 km Martian
atmosphere, and how it is helpful in refining the precision aerobraking
maneuvers, including "Where did all the water from Mars' surface escape?" -
there is also mention that variation is of the atmospheric is of the order
"10's of percent" (which I would think means 50% is possible if not common).

http://www.cosis.net/abstracts/EPSC2006/00644/EPSC2006-A-00644.pdf
Wow. Smooth cruising,
Doug
Received on Mon 28 Aug 2006 08:35:17 PM PDT