off to Mercury
Iron Meteorites Beware...
Mercury is a tough one to get to. Imagine rocketing towards a body one
million times larger than the earth. Then, at the last second, you
change course and attempt to go into orbit around a speck about the size
of our moon. That is the problem with going to Mercury.
Most planetary swing-bys use the gravity of a nearby body to accelerate
the spacecraft saving on fuel, and reducing the travel time. MESSENGER,
on the other hand, uses two Earth swing-bys, two Venus swing-bys, and
even two Mercury flybys to dump enough speed that a Mercury orbital
insertion is even a possibility.
Basically, MESSENGER is careening towards a cosmic cliff, clawing at the
gravity from other planets to slow its fall. And in the end, when
certain death is eminent a James Bond stunt pulls the tiny spacecraft
out of the path of the speeding sun and into a safe orbit around a
rather bizarre little world floating quietly at the very (inner) edge of
our solar system.
MESSENGER is a tough little robot. The hostile environment around the
sun makes powering the craft a piece of cake, but in this case, the cake
must be eaten in the oven. The business-end of the boxy craft sits in
self-made shade under a curved ceramic cloth umbrella. Tiny solar panels
poke out from the side, and even those are two-thirds mirrors.
Essentially, dumping heat as well as speed is the lifeblood of this
On August 2nd, MESSENGER lifted off the pad at Cape Canaveral in
Florida. Atop a Boeing Delta II Heavy-lift rocket, the spacecraft
punched through a lucky break in the weather and screamed into the night
sky beginning a mission that will last until 2013. Not that we have a
decade of data ahead of us. Instead all the speed dumping means
MESSENGER will not enter Mercurian orbit until 2011!
It was an exciting time surrounding the launch. I was at the Cape for
the meetings and other festivities, as well as the launch, but as luck
would have it, I could only stay for the first night's launch window.
The weather team scrubbed the mission at one minute before launch. Not
that we were all that hopeful, but the no-go came as the final 60
seconds were counted down.
The next night seemed to be a clone of the first, until 15 minutes
before the daily one second-long launch window opened (I'm told by a
friend who stayed on) when the sky cleared, the stars came out, the wind
died, and MESSENGER left home for a new life a measly 0.4AU from the
sun. But since I had to leave, the best I can do is point you to the
MESSENGER website to watch their launch video.
end, the oversized core of Mercury, its cratered past, and its magnetic
field will all shed new light on our knowledge of meteorites, with
particular attention to the irons. Lets talk again about this in 10
years. See you then!
MESSENGER's Principle Investigator Sean Solomon holding
his Mercury globe. Notice that half of it is blank. That
is because we have only seen about half of the planet
and that was 25 years ago with the Mariner 10
At the prelaunch science review meeting, Robert
Gold, an expert in space plasma, addreses some of
the major features of the MESSENGER spacecraft for
all those involved with the mission. While this
might look like a normal slide, read the text and
see just how much of this slide you really
For families, and non-scientists somehow involved with the
mission, a news briefing was held. This is where the
suit-and-ties from NASA showed up. Most of the science teams
prefered shorts and sandels as the proper attire for a hot
Clark Chapman, one of the instrument PIs from the Southwest
Research Institute (right) and myself pose on our way to the
hotel bar. I've never met anyone as passionate about Mercury
as Clark. And he has been working on NASA projects for years
and is one of the worlds leading experts on impact cratering!
Safety, among other concerns has forced most VIP
viewing of the launch is a pretty fair distance from
the rocket. TVs are set up in tents to show a
closeup of the rocket, which in this photo, is both
on TV and in the distance in the upper left.
spacecraft to Mercury is really the planting the seeds of knowledge.
Although we won't all be here in a decade, those who walk in our
footsteps will thank us for giving them these gifts, and for the
forthought to trust the future generations to appreciate the time and
resources we spent to keep the dreams alive.