[meteorite-list] Mars Reconnaissance Orbiter Nears End ofAerobraking

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Tue Aug 29 10:24:20 2006
Message-ID: <20060829142416.34414.qmail_at_web36901.mail.mud.yahoo.com>

Hi Doug, Ron, list -

Sadly, one must also remember that this type of
technology is also useful for warhead re-entry.
If we instead use it for something constuctive and
beneficial, such as improving our understanding of the
Earth's weather, then that's to the good. I suppose
that what I'm trying to say is that technology always
has two faces, and we always have to look at the uses
to which it is going to be put.

As far as Mars' lack of atmosphere and water goes,
both escaped to space long ago. Mars' molten core
cooled a long time back, and without its molten core's
magnetic field's protection from the charged particles
from the Sun, those particles carried Mars' water and
atmosphere away -

By the way, the holes in our ozone seem to be letting
in increased levels of UV which are melting ice in
Antartica and the Artic, which cold water is flowing
onto the surface of the world's oceans -

- all the best,
Ef


--- MexicoDoug <MexicoDoug_at_aim.com> wrote:

> 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
>
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Received on Tue 29 Aug 2006 10:24:16 AM PDT