Possibly more productive to talk about fixes:
Subject: NASA May Not Be Able to Prevent Shuttle Foam Loss
I think that my idea of a sacrificial leading
edge would fly.(an aerodynamic fairing that would quickly
burn away uniformly during the heat of re-entry, yet
protect the RCC tiles during the ride into orbit). Think
plain fibreglass - or a more reliably ablative and
heat-affected compound.
As it would be effectively a leading-edge
extension, it would increase wing chord slightly - and so
improve glide performance in the event of a sub-orbital
abort.
If NASA was concerned about it not burning away
uniformly during re-entry they could, whilst in orbit, utilize shielded
mild detonating cord (MDC - such as used to remove
fighter canopy plexiglass prior to ejection). The MDC (a directed
energy device) would blow it off along the length of each
leading edge - leaving the RCC intact.
NASA May Not Be Able to Prevent Shuttle Foam Loss, Board Says
July 11 (Bloomberg) -- NASA may
not be able to prevent some fuel-tank insulating foam
from falling off and striking the space shuttle during
its launch, the likely trigger for Columbia's
destruction, and is trying to find a way to get rid of it
in future missions, investigators said today.
The foam's construction and the
way it is manually sprayed onto the area known as the
bipod ramp, where the shuttle is connected by struts to
the fuel tank, could reduce the strength of the
insulation and lead it to break off, the Columbia
Accident Investigation Board said in a 189-page ``working
scenario'' posted to its Web site.
A chunk of foam suspected of
puncturing Columbia's left wing was shed from the bipod
area, according to investigators.
``It may not be possible to
control a manual process well enough to preclude defects
in the bipod ramp,'' the board wrote.
That finding is pushing the
National Aeronautics and Space Administration toward
eliminating the foam from the tank-shuttle connector, an
accident board member said today.
``A possibility is don't let
any bipod ramps come off and hit the wing leading edge,
which is where I think NASA is headed,'' Scott Hubbard,
who run's the agency's Ames Research Center in
California, told reporters today in Washington. ``One
answer is just don't ever let this happen again by
eliminating the source. I believe they are redesigning
the bipod ramp to completely take out the foam.''
NASA encases the tank in foam
to prevent ice formation and maintain the temperature of
the liquid oxygen and liquid hydrogen stored inside, the
propellants for the shuttle's main engines.
Destruction Demonstrated
The destructive power of foam
fragments was demonstrated this week at the independent
Southwest Research Institute in San Antonio, Texas, where
a 1.6-pound foam piece fired at a mockup of the shuttle's
wing edge tore a 16-inch hole in the heat shielding.
Hubbard said investigators had
found the ``smoking gun'' after the test Monday. The hole
would have let atmospheric gases as hot as 3,000 degrees
Fahrenheit stream into the interior of the wing during
reentry, melting its structure and eventually forcing the
shuttle to veer out of control and break apart, about 40
miles above Texas. All seven astronauts aboard were
killed.
The Southwest Research tests
``support the theory'' the left wing was damaged by the
foam impact, the board said. The board's ``scenario''
report estimates the size of the hole in Columbia was
smaller, about 6 to 10 inches in diameter.
Retired Admiral Harold Gehman,
the board's chairman, said during a press briefing in
Washington that the panel has completed its probe and is
writing its final report on the shuttle's destruction,
set for release in mid-August.
NASA might need to treat
shuttles as developmental vehicles in order to prevent
future problems that could lead to their destruction,
board members said today.
`R&D Vehicle'
``A lot of this boils down to
not treating the shuttle as operational, but as an R&D
vehicle,'' said Brigadier General Duane Deal, a commander
with the U.S. Air Force's 21st Space Wing. ``You need to
treat each launch as the first launch, each orbit as the
first orbit and each reentry as the first reentry.''
Gehman said that meant there
would have to be more scrutiny of the vehicles as they
are prepared for launch and during their missions. ``You
are always on the lookout for tiny little differences,
you're suspicious of tiny little differences,'' he said.
The main mission of the shuttle
is to deliver crews and building materials to the
International Space Station, the largest space project,
and to repair the orbiting Hubble Space Telescope. A
Houston-based joint venture of Boeing Co. and Lockheed
Martin Corp. prepares the shuttles for launch.
Last Updated: July 11, 2003