The dense, brittle foam
will likely fall off the new rocket just like it has from the shuttle's
external fuel tank, they said. But NASA doesn't expect it to pose any safety
concerns.
Used as insulation for
tanks that hold super-cold rocket fuels, foam has been falling off the
shuttle's huge, orange tank since the earliest flights.
A piece of foam the size of
a briefcase hit one of Columbia's wings during liftoff in 2003, causing a hole
that resulted in the orbiter burning up on re-entry and killing seven astronauts. Foam also came off
during the subsequent flight of Discovery.
Part of the new manned
rocket, called Ares I, will include a section similar to
the shuttle external tank. So it, too, needs the foam, according to upper stage
project manager Danny Davis.
But unlike on the shuttle,
astronauts will ride in a six-person capsule that sits atop the rocket. That
means any falling foam won't hit the crew compartment, said Don Krupp, chief of
the vehicle analysis branch at Marshall Space Flight Center.
"This is a different
application,'' Krupp said. "If we have any foam debris it falls away from the
astronauts. They're ahead of it.''
Davis said engineers
working on Ares assume that the spacecraft will shed foam.
"But it just won't
matter,'' he said.
Davis and Krupp were among
NASA managers who met with reporters during an open house for the media at
Marshall, which manages the shuttle's rockets and is designing propulsion
systems for the new lunar spacecraft.
Engineers developed the
Apollo spacecraft in the 1960s using slide rules and handmade models, but Ares
is being designed on computers. Engineers can test their ideas on virtual
models, letting them know quickly which designs won't work.
Built in stages, Ares I
will be stacked atop a single solid-rocket booster larger than the ones that
lift the space shuttle into orbit.
Ares will fly higher and
faster than the shuttle during the moments right after launch, making it
subject to more stress. But with a cylindrical design, it won't have the shuttle's
wings, tail or delicate heat-shielding tiles.
That difference should make
the new rocket less susceptible to launch delays because of bad weather at Cape
Canaveral, Krupp said.
"We are trying to design
this vehicle to fly in any weather,'' he said. "Our goal is to not let weather
constrain our launch window.''
The Ares rocket will
include concepts used in both the Apollo and shuttle programs, but Krupp said
every piece that goes into the new spacecraft will be tested like it was brand
new.
"I do not want to have
another Challenger or Columbia on my watch. We do not want to lose another
astronaut,'' he said.
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