[meteorite-list] Ice Diary 9: Climbing the Mountains of Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:10:09 2004
Message-ID: <200304171615.JAA25112_at_zagami.jpl.nasa.gov>

http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=432&mode=thread&order=0&thold=0

Ice Diary 9: Climbing the Mountains of Mars
Astrobiology Magazine
April 17, 2003

Summary: The Ice Diary series explores the adventures of a dedicated group
of meteor hunters. The National Science Foundation, NASA and the Smithsonian
collect and curate extraterrestrial samples scoured from the South Pole. The
diary entries provide a personal tour of a recent expedition, with all the
immediacy of being there.

Ice Diary 9

Climbing the Mountains of Mars

1 January, 2003

Boy have we been working hard lately! We are nearing the 400-meteorite mark
and are hoping to break the 500-meteorite mark before we leave. The weather
hasn't been cooperating, though. Yesterday started out calm and relatively
warm. By the time we started our searching, the wind had picked up to at
least 15 knots and the temperature was right at 0F. We recovered 17
meteorites before we called it a day.

These were some of the most beautiful meteorites I've seen this whole trip.
Two of them appear to be achondrites. Meteorites basically fall into two
groups: chondrites and achondrites. Chondritic meteorites come from small
asteroids that never formed a core, mantle, and crust at the origin of the
solar system. They are composed of chondrules: small round, spherical
concretions that probably represent droplets of material from the
protoplanetary disk that existed 4.6 billion years ago. Achondrites don't
have chondrules and come from larger bodies that do have a core, mantle, and
crust. What's more exciting is that martian and lunar meteorites fall into
the classification of achondrites. Saying that we found a couple of
achondrites doesn't necessarily mean we found meteorites from Mars or the
Moon, but it is a possibility.

The ANSMET P.I., Dr. Ralph Harvey, pointed out to me that NASA is very
interested in finding more Martian meteorites because they provide the most
information on Mars without actually going there. Ralph also enjoys
involving NASA with ANSMET because, at heart, he is interested in the
exploration of space.

According to Ralph, "In some ways, it's very much like a science fiction
story, where astronauts come to Antarctica to train for a mission to Mars."
Dean is keeping a journal of the dynamics of a small field team working
under these conditions in order to help NASA prepare astronauts for a Mars
mission.

Dr. Cady Coleman is the second astronaut to join an ANSMET team, and will
probably not be the last. Ralph commented that astronauts are physically
fit, adventurous, and are able to complete a job under demanding conditions.
That makes them ideal ANSMET members.

2 January, 2003

There have been a few requests for the female perspective, so greetings from
the females of the Beardmore ANSMET team!

Living in the extreme environment of Antarctica is the same for us as with
the rest of the team. Everyone pulls some weight - literally - from lashing
sleds, lifting boxes, putting up our own tent, fixing snowmobiles, and much
more. Do we work hard? Yes! Are we tired at the end of the day? Absolutely.
But so are the guys. Being here is hard physical work, and even just dealing
with the cold will tire you out.

So with all the similarities between us and the guys, what are the
differences? Our tent, for one. The tent is more than just the place where
we keep warm; it is our home away from home. It is filled with reminders of
our family, friends and home. Linda brought a huge wad of photos that she
changes out every few days. We have holiday decorations -- Nancy's Mom sent
her some great Christmas socks and hair ornaments.

Daily chores keep us healthy and warm. As soon as we get out of the field,
we fill stoves and chip ice. Nancy and I take turns without ever really
keeping track. We don't spend a lot of time deciding what we want to eat
each night, nor do we follow any type of schedule. All of it gets done
sometime before bed, which happens to be the latest in our neighborhood,
generally close to midnight. It's hard to believe, but Nancy has a fair
number of scientific responsibilities that can take upwards of two hours --
downloading the GPS data for the day is the main one.

We usually end the evening by filling our stoves and water bottles for the
next day. A little reading until the tent gets too cold, and then we cocoon
under the sleeping bags. We also get up the latest, about 7:30. Neither of
us are big breakfast eaters. Speaking of food, we would like to point out
that we eat pretty differently out here than at home. Lots of meat and
butter and fat go into our meals, while those foods that can't be frozen
(soda, pizza, sour cream, lettuce, fruits) are not available. Amazingly, we
crave all that fat in order to keep up our energy (gotta lug almost 10 extra
pounds of bunny boots all day) and stay warm. Linda is not a big chocolate
eater, but she has found herself eating a bar a day -- and has still lost a
few pounds!

Other differences between life in a tent versus life back home are related
to indoor plumbing and access to large quantities of hot water. We get
pretty dirty out here after weeks of no showers, and we are willing to
accept that, especially since everyone else is in the same boat. We leave
all the usual toiletries behind. We care very little about how we look,
although we keep an eye out for frost nip and other cold weather conditions
that might appear on exposed skin. Keeping warm is more important, although
Linda hates how much like a blimp she looks in all that gear. Linda doesn't
even look in the mirror unless Nancy is laughing at her hat hair. Of course,
we are looking forward to tomorrow evening, which will be our second "bath"
night in the field. Linda has even gone so far as to run around outside
without a hat just so everyone will see her clean hair, if only for that
day. We also suspect that we use many, many more baby wipes than the men do.

So how do the guys treat us? Just like anyone else, which is great, ideal,
perfect. We're a good, hard-working team. It is worth noting that the other
ANSMET team in the field right now, the reconnaissance team, has equal
numbers of men and women (2 of each). Last year at one point in the ANSMET
season, there were 5 women and 3 men in camp. There have been a lot of women
involved with ANSMET teams over the years.

3 January, 2003

After a short weather delay, we headed back to That" Moraine this morning
for a systematic foot search. I don't think any rock was left unturned, nor
was any wind scoop unexplored. At the end of this methodical search, we
found 14 meteorites.

We decided to use the afternoon for a reconnaissance trip. We traveled 20
minutes north of camp to a blue ice field only visited once before by Jamie
and Danny. Fuel was stored there from the Beardmore Camp, so Jamie and Danny
brought some of it back to our MacAlpine Camp. Danny said the ice was "like
a frozen tsunami," and I think he was exactly right. A large wind scoop is
formed where the ice meets the mountain, causing the blue ice to plunge
toward the barren rock.

We hiked up a small peak to get an idea of the extent of the blue ice and
how we should go about searching it. Once again, it was strange to set foot
on dry, snow- and ice-free ground. This rock was formed from iron-rich
volcanic rocks and had a slightly rusty appearance. I felt as if I was
climbing a mountain on Mars, and one of the reasons I wanted to come to
Antarctica is that it is the closest terrestrial analog to Mars.

On the way back down, Jamie found a meteorite on dry soil, and another was
found on the blue ice. We spent a lot of time on that ice, but mostly saw
small windblown rocks until Dante found the largest meteorite of the day. It
makes me wonder when we find one lone meteorite in a field of blue ice - was
it brought there by the flow of the ice, or did it come from a recent fall?

I find it remarkable that these rocks from space even make it to Earth. It's
generally accepted that most meteorites come from asteroids. They are
produced when asteroids collide, and their debris falls into an orbit that
intersects the Earth's orbit. They enter our atmosphere travelling at speeds
anywhere from 17,000 to 40,000 miles per hour. As they pass through the
upper atmosphere, friction with air particles causes the outside of the
meteorite to attain temperatures and a luminosity comparable to the surface
of the sun!

However, rocks are poor conductors of heat, so the inside of the meteorite
stays very cold. The meteorites we find have a thin black crust that looks
completely different from the interior of the rock. (Meteorites don't
weather much in Antarctica, so they retain their black fusion crust long
after they fall.) Some meteorites melt partially and take on a shape not
unlike the bottom of the space capsules used early in the space program.
These meteorites are described as "oriented."

In addition to these high temperature contrasts, the meteorite is also
slowing down at an extreme rate. This causes it to experience G-forces that
are completely outside of the experience of most people. In my classroom, I
usually find a student who weighs about a 100 pounds. I explain that just
sitting in her desk, she's experiencing 1G of force. If she were in a car
going around a corner quickly or braking quickly, she could experience 2Gs,
and therefore, for a moment, weigh 200 pounds. On a roller coaster, she can
achieve 4Gs, so she weighs 400 pounds. But if she were a meteorite, she
could experience as many as 300Gs when entering the atmosphere. For the few
seconds she's plummeting to Earth, she weighs 30,000 pounds!

Meteorites are just rocks, and most of them (especially the stony ones)
cannot take this force and break up anywhere between 10 and 20 miles above
the surface. Fragments of the meteorite rain down over a large area called a
strewn field." In most cases, the meteorites soft" land without making a
crater. People who have recovered meteorites after witnessing them fall
often describe them as cold to the touch. Although legend and folklore say
they start fires and are radioactive, the only dangerous ones I know of come
from Krypton and are harmful only to Superman.

We often find several meteorites together that look like they could have
come from the same fall. The glaciers do a good job of mixing them up, so
it's hard to tell just by looking at them. They can be analyzed later by
extremely precise instruments that can identify trace elements and
compounds. This can tell us about the chemistry of the early solar system,
so we are careful when collecting the meteorite. We would hate to see a new
class of meteorite identified because my candy bar scraped across it. I can
see the headlines now, "New meteorite: part rock, part iron, part nougat."

----------------------------------------------------------------------------

Since 1976, the Antarctic Search for Meteorites program (ANSMET),
funded by the Office of Polar Programs of the National Science
Foundation, has recovered more than 10,000 specimens from meteorite
stranding surfaces along the Transantarctic Mountains. Dr. Ralph Harvey and
John Schutt are members of each field party, serving as ANSMET continues to
be one of the few Antarctic research projects that invites graduate students
and senior researchers from other institutions to participate in our field
work on a volunteer basis--including the Teacher Experiencing Antarctica
(TEA) program. As a multi-agency collaboration, the NSF supports field
operations, NASA supports storage curation, distribution and notification of
recovered samples, and the Smithsonian provides long term curation
facilities for the collection and assist in sample characterization.

In this multi-part Ice Diary series, all commentary is attributed to Andy
Caldwell unless otherwise noted, and reprinted by permission as part of his
participation in the TEA program.
Received on Thu 17 Apr 2003 12:15:46 PM PDT