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April
21, 2008: At this year's Great
Moonbuggy Race in Huntsville, Alabama, Prof. Paul Shiue
of Christian Brothers University was overheard joking that
duct tape was his team's "best engineering tool."
Others felt the same way. The sound of gray tape being torn
from rolls practically filled the race course as dozens of
college and high school student engineers busily assembled
and repaired their homemade moonbuggies.
Little
did they know, this was in the finest tradition of lunar exploration.
Turning back the clock 36 years reveals the key roll of duct
tape in NASA's Apollo program:
The
date was Dec. 11, 1972. Astronauts Gene Cernan and Jack Schmitt
had just landed their lunar module Challenger in
a beautiful mountain-ringed valley named Taurus-Littrow on
the edge of the Sea of Serenity. Mission planners chose the
site for its geological variety: the ground was covered by
a mix of giant boulders, hardened lava, orange glass beads
(a sign of ancient volcanic fire fountains) and, of course,
ubiquitous moondust. The valley itself was a fracture created
in the aftermath of an asteroid impact billions of years ago;
the history of the Moon, many suspected, might be written
along its walls. Jack Schmitt, the first geologist on the
Moon, could hardly wait to get started.
Above:
Apollo 17 astronauts and moonbuggy in the Taurus-Littrow valley.
[More]
About
60 seconds after touchdown, Schmitt radioed Houston, "Batteries
look good," followed by a brief pause, and "Oh,
man!! Look at that rock out there!"
Cernan
agreed, "Absolutely incredible."
Within
hours the two astronauts were down the ladder loading a raft
of geology tools and experiments onto their Lunar Roving Vehicle
or "moonbuggy." Everything was going smoothly until
Cernan brushed against the rover; a hammer in the shin pocket
of his spacesuit caught the buggy's right rear fender and
tore half of it off.
Cernan:
"Oh, you won't believe it. There goes a fender."
Schmitt:
"Oh, shoot!"
Now,
a moonbuggy in Alabama can go just fine without a fender,
but in Taurus-Littrow a missing fender was a potential disaster.
The reason is moondust. When a rover rolls across the lunar
surface, it kicks up a plume of moondust in its wake. (Astronauts
called them "rooster tails.") Without a fender,
the rover would be showered by a spray of dark, abrasive grit.
White spacesuits blackened by dust could turn into dangerous
absorbers of the fierce lunar sun with astronauts overheating
inside. Sharp-edged dust wiped off visors would scratch the
glass, making helmets difficult to see out of. Moondust also
had an uncanny way of working itself into hinges, latches
and joints, rendering them useless.
Above: Apollo 17 moonbuggy fender repaired
with duct tape.
Cernan:
"And I hate to say it, but I'm going to have to take
some time to try … to get that fender back on. Jack, is the
tape under my seat, do you remember?" (He's referring
to a roll of ordinary, gray duct tape.)
Schmitt:
"Yes."
Cernan:
"Okay. I can't say I'm very adept at putting fenders
back on. But I sure don't want to start without it. I'm just
going to put a couple of pieces of good old-fashioned American
gray tape on it...(and) see whether we can't make sure it
stays."
In
spite of his thick gloves, Cernan managed to unroll and tear
off the needed pieces, but moondust foiled his first repair:
Cernan:
"…good old-fashioned gray tape doesn't want to stick
very well." (At a post flight briefing he explained:
"Because there was dust on everything, once you got a
piece of tape off the roll, the first thing the tape stuck
to was dust; and then it didn't stick to anything else.")
His
second attempt succeeded, however. "I am done!"
crowed Cernan. "If that fender stays on ... I'd like
some sort of mending award." And with that, they were
off.
For
the next four hours they drove the moonbuggy far and wide
around the landing site, stopping to drill holes and collect
core samples, deploy seismic charges and set up other experiments.
Even with all four fenders, Cernan had to dust off the rover
at each stop (mission planners provided a special moondust
brush for the purpose). This soaked up many minutes of
valuable time, but could've been worse as they were about
to discover.
Right:
Gene Cernan works with his roll of duct tape. Click
to view a longer movie with sound.
Driving
across a rough patch of lunar terrain, Cernan commented, "Man,
you could lose the rear end of this thing in a hurry."
And, indeed, the fender fell off again. Duct tape held it
for a while, but moondust had reduced the tape's stickiness
too much to hold on for a whole EVA (Extra-Vehicular Activity).
Schmitt:
"I think you have lost your fender. I keep getting rained
on here (with lunar dust)."
Cernan:
"Oh, no!"
Schmitt:
"Look at our rooster tail."
Subsequent
stops required considerable housekeeping. "Let me run
around and dust!" radioed Cernan while Schmitt deployed
the Surface Electrical Properties (SEP) experiment. In a post-flight
briefing he noted, "The dust on the battery covers and
everything else was thick enough to write in. With a working
fender you'd always got a light film of dust; but this was
'dirt' dust."
Back
at the Challenger, Cernan gave the parked rover a
rueful inspection. "Oh, man, I tell you, it's going to
take us half a dozen Sundays to dust. Look at that fender;
that's terrible. Boy, that one fender just [creates] an order
of magnitude more of a dust problem."
Back
in Houston, NASA engineers understood the seriousness of the
situation. If they couldn't come up with a solution while
Cernan and Schmitt slept, the next day's exploration could
be severely curtailed. The astronauts might even be limited
to walking distance.
Right:
Gene Cernan, back in the lunar lander after a long EVA. The
smudges on his forehead and longjohns are moondust. Photo
credit: Jack Schmitt. [More]
But
they did come up with a fix and it called on, you guessed
it, duct tape.
When
Cernan and Schmitt woke up the next morning, mission control
explained how they should tape four laminated maps together
in the shape of the missing fender. "Just call me the
little old fender maker," said Cernan as he tore off
pieces of gray tape. This time the taping was done inside
the relatively dust-free confines of the lunar lander, so
the duct tape retained its usual stickiness. Clamped to the
moonbuggy, the new fender held for the rest of the mission,
which included another 15 hours of EVAs.
One
dousing with dust was enough to make a deep impression on
Schmitt. Back on Earth he opined that "the dust issue
is one that just has to be addressed. It's going to be the
major environmental issue for future missions to the Moon."
Back
to the future: Right now, NASA is preparing a return to the
Moon and dust is very much on the agency's mind. NASA scientists
are doing laboratory experiments with samples of Apollo moondust
to discover techniques for "moondust mitigation."
And a new NASA spacecraft named LADEE is devoted entirely
to moondust. Short for Lunar Atmosphere and Dust Environment
Explorer, LADEE will orbit the moon in 2011 or 2012 watching
for "dust storms" thought to occur when electrostatically
charged moondust levitates off the lunar surface.
When
next-generation astronauts go to the Moon, they'll know a
lot more about moondust than their Apollo predecessors. But
you can bet there’s one thing they won’t leave home without—"good
old-fashioned American gray tape."
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Author: Dr.
Tony Phillips | Credit: Science@NASA
more
information |
Apollo
Chronicles: "Moondust and Duct Tape"
is the fifth episode of Science@NASA's Apollo Chronicles:
Thanks:
The author would like to thank Eric
Jones who penned the Apollo
Lunar Surface Journal, a must-read for historians
of the Apollo program. Many of the radio transmissions
and recollections reported in this story come straight
from the Journal.
Fender
Facts: The piece of fender accidentally broken
off by Gene Cernan was a "retractable fender extension."
Fenders had to retract so that the moonbuggy could be
folded up in a compact storage space during its trip
from Earth to Moon. The fender extension that Cernan
first taped back on to the moonbuggy and that later
fell off was never recovered; it is still on the Moon.
The other three fenders and the replacement "map
fender" were brought back to Earth. Two fenders
are on display at the Kansas Cosmosphere museum in Kansas;
one fender plus the map are on display at the Smithsonian
National Air and Space Museum in Washington, DC: more.
NASA's
Future: US
Space Exploration Policy |
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