SETI bioastro: Biological Mars exploration on the cheap: some notes

From: Larry Klaes (lklaes@bbn.com)
Date: Tue Apr 25 2000 - 12:45:40 PDT


From: "Bruce Moomaw" <moomaw@jps.net>
To: "Europa Icepick Group" <europa@klx.com>
Subject: Biological Mars exploration on the cheap: some notes
Date: Mon, 24 Apr 2000 11:55:08 -0700
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 4.72.3155.0
X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3155.0
Sender: owner-europa@klx.com
Reply-To: europa@klx.com

        Jayme Blatschke wrote:

        "Personally, I'd like to see all talk of a sample return mission
banned at NASA. I'd like to see orders for a half-dozen Pathfinder-style
missions put in, maybe getting a volume discount, and launch one of these
every two years for the next decade or so. Maybe swap out an instrument or
two, but keep things basically the same, adding improvements as we go. After
all, there are many, many places on Mars where this would be a viable
exploration tool. Drop one in Valles Marineris fer crying out loud. Or
three. Plop one on an ice cap during the time of the midnight sun. And get
that Martian balloon explorer on the fast track. All of this stuff will give
you the maximum scientific return (and PR appeal) for the dollar. A sample
return would bring back *maybe* something the size of an Allan Hills
meteorite, when we can send someone to search Antarctica Mars rocks for a
billionth of the cost."

        Well, it's a extremely serious mistake to spit in the eye of Mars
sample return -- the sensitivity and variety of instruments and analytical
techniques that can be applied on Earth to a returned sample (many of them
not even invented yet) is stupendously greater than any paltry little
instruments we could send to Mars. The big argument for sending a set of
smaller probes to Mars first is simply that sample-return missions will
always be expensive as hell and few in number, and will only return a few kg
of samples each -- so we damn well better know the optimal places to land
them.

        I agree that Mars meteorites are a priceless asset, but igneous Mars
meteorites (which are all we've found so far) are a very poor place to look
for microfossils -- after all, they're chunks of hardened lava. We very
badly need to locate some Martian sedimentary-rock meteorites, which would
be infinitely more promising as a possible microfossil or chemical-fossil
source -- but at this point we don't know what they would look like, or even
whether sedimentary rocks are hard enough to survive being blasted to Earth.
(That very cheap experiment carried out by the Beagle 2 people -- in which
some pieces of sedimentary rock were fastened to the heat shield of a
Russian satellite to see if they could survive Earth re-entry and what they
would look like afterwards -- was an important first step, but we need more
follow-up. It suggested that some of them can survive, but also that Earth
entry may radically change them both in appearance and chemistry. Finding
and determining the nature of in-situ Martian sedimentary rocks -- so that
we can recognize any here -- would also be a very important and useful task
for lightweight Mars landers.)

        In this connection, there are two very relevant abstracts on Mars
exploration in that invaluable collection of IAA abstracts on low-cost Solar
System exploration that I mentioned last night:

http://sd-www.jhuapl.edu/IAA/IAAabs.pdf

        On page 27, there's a JPL piece on possible ways to miniaturize a
Mars sample return mission to accomplish it WITHOUT either an automatic
rendezvous in Mars orbit or processing of Mars' air to refuel the ascent
vehicle on Mars -- something I would have thought impossible:

        "Miniaturization of the Mars Ascent Vehicle (MAV) will make possible
a direct sample-return mission from Mars with a single Delta 2 launch. This
will dramatically decrease the costs and risks of Mars sample return, and
will enable sample acquisition from differnt locations... The Mini-MAV was
designed initially for rendezvous with the [sample retrieval] orbiter in a
circular orbit around Mars. Addition of one more solid stage may launch the
upper stage with the sample canister on a direct-to-Earth trajectory. This
paper presents the concept, and discusses the features and challenges of the
launch, navigation, communications and control." This confirms that Mars
sample return needs to wait until new technology developments have
significantly cut the weight and cost of the mission -- as they already have
to a huge degree since the Seventies. (And, as Freeman Dyson says, this
kind of miniaturization can be done on unmanned space missions, but not on
manned ones -- unless you're a DC Comics character.)

        Second, Jayme Blaschke and I have talked optimistically -- and Scot
Stride pessimistically -- about the potential of the "Mars Scout" concept.
On pg. 24-25 of the IAA abstract collection, there is a detailed description
of a sensational-sounding JPL/Goddard mission that might combine a
surface-landed Mars Scout, a Mars reconaissance balloon, and a detailed
subsurface search for organic compounds -- all in a single Mars
Micromission(!):

        "A surface package including a miniaturized Gas Chromatograph/Mass
Spectrometer and a 1.2 meter drill would be delivered to the surface by a
solar-heated hot air balloon (known as a solar Montgolfiere). The balloon
system would be deployed about 8 km above the surface of Mars, whre it would
rapidly fill with Martian atmosphere and be heated quickly by the sun. The
combined buoyancy and parachute effects of the solar balloon result in a
surface package/airbag impact of about 9 m/sec -- less than half
Pathfinder's impact speed, and without Pathfinder's heavy, expensive
retrorocket landing system.

        "After delivery of the GCMS package to the surface, one option is to
allow the balloon to ascend, using solar heating, to as high as about 7 km
altitude, with imaging, magnetic and atmospheric data being taken by a small
science gondola for the remainder of the daylight hours. This would allow
the balloon to perform science measurements over many hundreds of kilometers
as it travels downwind.

        "Total atmospheric entry mass of this mission (including 30% payload
margin) is estimated to be 40-45 kg (with or without the post-landing
balloon mission), and it can fit as an Ariane 5 piggyback payload for a 2005
or 2007 launch.

        "The GCMS would obtain samples directly from the atmosphere at the
surface, and also from gases evolved from solid material collected from as
deep as 1.2 meters with a [Honeybee Robotics] drill. [Honeybee has already
developed the lightweight drills planned for the Athena Mars rover and the
Champollion comet lander.] Compared to the Viking GCMS, the experiment
would obtain samples from a much greater depth, and would search for organic
molecules trapped in ancient stratified layers well below the oxidized
surface. The experiment would also measure trace atmospheric constituents,
and obtain precise isotope measurements of atmospheric noble gases and
elements.

        "The solar-powered Montgolfier balloon system has recently been
demonstrated in Earth's stratosphere at 33 km altitude (the 0.008 millibar
pressure level) as deployed from an entry-shaped vehicle while falling at 50
meters/sec on a parachute. The lightweight balloon requires about 2 minutes
to fill and an additional minute to attain fully heated buoyancy. The
landed GCMS/drill package would achieve all of its primary scientific
objectives in the first few hours. The maximum lifetime of the lander
experiments would not exceed several days, with the exception of an imaging
and weather station, which may be powered for about one month.

        "The GCMS would be a simplified version of the one on the Huygens
Titan probe, and would achieve substantial improvements in sensitivity and
precision in isotopic measurements compared to Viking's GCMS. The drill
would be similar to that developed for the Champollion comet lander, and it
has undergone testing on both loose and very hard materials."

        Sounds nice, no? I'll add only that JPL Technical Reports have
described detailed designs for a Mars solar hot-air balloon concept for 2 or
3 years now -- it can even be used for repeated landings and takeoffs, and
it seems to be somewhat lighter than a helium balloon.

                                                                Bruce Moomaw

Jayme Lynn Blaschke
_______________________
The Blaschke Home Realm
http://www.vvm.com/~caius

Blaschke Exotics
http://www.exoticdeer.org

==
You are subscribed to the Europa Icepick mailing list: europa@klx.com
Project information and list (un)subscribe info: http://klx.com/europa/



This archive was generated by hypermail 2b30 : Wed Mar 28 2001 - 16:07:53 PST