[meteorite-list] The Grand SLAM: Rocketing Water to the Moon

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed May 24 17:04:51 2006
Message-ID: <200605242050.NAA27442_at_zagami.jpl.nasa.gov>

http://www.space.com/businesstechnology/060524_slam_moon.html

The Grand SLAM: Rocketing Water to the Moon
By Leonard David
space.com
24 May 2006

BOULDER, Colorado - A strikingly simple concept would provide efficient
water provisions for human outposts/bases on the Moon. The idea is to
repeatedly clobber our already crater-rich neighbor with tons of water
ice - to establish an "anywhere, anytime" delivery system.

Not only could chucking a payload of water ice to the Moon help sustain
an expeditionary crew there, the impact mimics - in experimental form - a
comet strike. Therefore, it's a double-whammy: A science mission wrapped
within an exploration capability test mission.

Spearheading the speculative ploy - called SLAM - is Alan Stern, executive
director of the Space Science and Engineering Division here at Southwest
Research Institute (SwRI). He's the lead scientist on another far out,
but on the way, endeavor - the New Horizons spacecraft that is outbound
for Pluto.

"I hope the SLAM idea stimulates thought and gets people thinking a
little bit more out of the box," Stern told SPACE.com. "When we have
people on the Moon, they are going to need water. This is an
exceptionally efficient, low-cost way to get it there."

Cold traps, lukewarm thoughts

One perplexing issue for scientists and lunar exploration planners is
just how much water ice is at the Moon's poles in the first place.

Spacecraft that orbited the Moon - the Pentagon's Clementine (1994) and
NASA's Lunar Prospector (1998-1999) - relayed data that hydrogen, arguably
in the form of water ice, might be stashed within permanently shadowed
craters - called "cold traps" - at the lunar poles.

And, if water ice is there, that resource could be used by visiting
astronauts to make rocket fuel and oxygen. But is it there or not? And
if so, how much water ice is available and in what condition for processing?

NASA's back to the Moon thinkers are anxious to sort out the truth about
this possible lunar water inventory.

For instance, joining in on the robotic assault on the Moon by several
nations over the coming years is NASA's Lunar Reconnaissance Orbiter (LRO).

Thermal jacket

On LRO's 2008 mission a newly announced "secondary payload" is the Lunar
CRater Observation and Sensing Satellite (LCROSS). The LCROSS will
monitor the impact of a spent upper stage from the same mission,
leftover hardware that would impact a crater in the Moon's south pole
area. A plume of material should be tossed high above the Moon's
desolate landscape - then sensor-scanned in a look for lunar water ice.

If found, getting at that water ice at the poles won't be easy. Working
people and machinery in those cold trap climes would be tough. Light and
power reserves aren't easy to come by. Communications in and out of
those locales is an issue too.

And that's where SLAM meets these difficulties - head on.

SLAM needs no mid-course correction en route to the Moon, nor a
spacecraft for that matter. All that's necessary is a thermal jacket for
the water ice payload that's flung by rocket booster toward any selected
spot on the Moon.

"It appears to be entirely feasible, simple, and really cheap," Stern
said. A proprietary technique would be utilized to keep the water ice
ball from being buried too deep on impact.

At lunar impact speeds, virtually all of the ice will come to rest less
than 5 feet (1.5 meters) below the surface if properly pre-fractured.
Also, work done on the concept indicates that a majority of the water
ice that is slammed into the Moon is retained, with only 15 percent
vaporized.

Clean water act

SLAM could even serve as an emergency, launch-on-demand service, Stern
continued, for lunar-situated crews in need of a rapid recharge of
oxygen, hydrogen, or liquid water to drink.

SLAM is also, in a way, a "clean water act" for the Moon. No telling
what the quality of water ice, bacteria-wise, might be available in
those darkened polar craters - if indeed it's there.

Another ballistic bonus of SLAM is creation of a calibrated comet impact
crater. The shot-to-the-Moon ball of ice is a little comet, Stern noted.

Moreover, scientists could study the transport efficiency of water on
the Moon. Molecules of water that are introduced into the lunar
environment from outside sources hop around like being on a griddle -
but a certain percentage make their way to the poles. The survival rate
of those water molecules is a great scientific question, Stern said.

"SLAM is a nexus of three or four things in exploration and science,"
Stern said. "I defy you to find a space mission that's cheaper or
simpler" than a mission that involves just two things: A rocket and a
garden hose left behind at the pad, he pointed out.

Breaking the Gordian Knot

Rockets lifting thousands of gallons of water skyward has been part of
U.S. space history.

In the early 1960's, test missions for the Saturn 1 booster included
hurling water-filled upper stages into space, even dumping loads of
water into Earth's upper atmosphere under Project Highwater.

"SLAM was designed to take advantage of the high performance and
precision injection capability of the existing Atlas 401," said Bernard
Kutter, Manager of Advanced Programs at Lockheed Martin Space Systems in
neighboring Denver.

Kutter explained to SPACE.com that, by utilizing existing Atlas
capabilities, SLAM can provide a low cost, low risk, novel lunar science
mission furthering our understanding of the Moon and water transport
around the Moon.

SwRI's Stern emphasized that SLAM is the output of roughly a dozen
people that tackled a set of issues - to break the Gordian Knot between
the value of polar volatiles and the difficulty of polar operations.

"To us it made a lot of sense. We couldn't find an obvious flaw in
it - not to say that it doesn't have pros and cons," Stern explained. One
constraint is that an Earth-to-Moon ice ball strike must take place
during lunar night, he said, with mining recovery necessary before
sunrise to prevent ice sublimation after impact.

That's a practical, real-world problem, Stern observed, just as deep
ocean drilling here on Earth has its problems too. In exchange for those
troubles there are great rewards, he said.

"We're proud of the SLAM idea," Stern concluded. "It'll be up to others
to see if this concept, I guess you could say, 'holds water'."
Received on Wed 24 May 2006 04:50:01 PM PDT