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Shuttles Grounded Once Again
PipianJ writes "After discovering that the piece of the shuttle that fell off mysteriously, not actually striking it, (as reported earlier) was a piece of foam insulation not unlike the piece that ended up in the destruction of Columbia, Yahoo News reports that NASA has once again grounded the shuttle fleet."
NASA needs to re-adopt the paint on the external tank. At least on the shuttle side of the tank, the foam insulation needs a coat of paint to eliminate the porosity of the foam. That will lock the ice out of the foam and prevent it from tearing it off the tank.
The paint probably ought to be non-stick coated to inhibit excess ice formation too. Then put heaters in critical locations to break up the ice while the shuttle stack is sitting on the ground, or still moving at slow speeds. That way, supersonic chunks of ice won't go zinging into the shuttle body and we don't have to wonder if we've launched another one way mission to space.
Behold, this dreamer cometh. Come now, and let us slay him... and we shall see what will become of his dreams.
Except Discovery is not "seriously damaged".
(And another shuttle would hardly be "scrambled".)
And the fact that the over 15,000 pieces of debris that hit the shuttle on the previous 113 flights didn't cause any problems 112 of those 113 times. You might say once is too many, but we're only finding issues here because we're looking so hard.
And, no, it's not "hard to do" with one shuttle on orbit. The fleet is grounded. Discovery is on orbit. Once it returns, no further shuttles will be launched until further notice. Quite simple.
In response to an edict from the EPA, NASA was required to change the design of the thermal insulating foam on the shuttle's external tank. They stopped using Freon, or CFC-11, in order to comply with the 1987 Montreal Protocol, an agreement designed to head off doubtful prognostications of an environmental disaster. This resulted in 10X the level of tile damage since 1997 (when the new foam was implemented) per flight.
I hope this isn't what caused the damage we've seen lately, but if it is, it begs the question, is it worth using CFC-11 for safer shuttle flights given the relatively small number of launches that occur?
Close, but not quite.
The shuttle-as-the-second-stage-of-a-Apollo V was an alternative to the SRBs later in the design.
I liked that idea signifigantly better, because the Saturn V stage would have been useful for other things...
The shuttle was initially supposed to be all-reusable. Two shuttle-vehicles would launch together and one would go all the way to orbit and the other would go back to the ground. They could do it, but not in the budget given with the performance required. They could have made it smaller but fully reusable and in budget, or use a drop tank and make it bigger and stay in budget.
Gentoo Sucks
Was there any/much foam shedding prior to the removal of paint from the external tank?
Just wondering what the adhesive effects of all that white paint were.
http://www.spaceflightnow.com/shuttle/sts114/05072 7palrampimages/
looks an awful lot like the unidentified chunk of debris that missed the starboard wing (scroll to bottom of link).
http://www.spaceflightnow.com/shuttle/sts114/05072 6images/
"the shuttles have been hit with debris over 15,000 times, mostly during launch."
You can rationalize it all you want but the fact is its a bad design. A couple basic reasons:
- The foam is applied by hand to the ET, it is a hack added after the design was done to deal with all the ice that they had to know would be there. but chose to TOTALLY ignore in the original design. Applying that foam by hand is an accident waiting to happen, because it ends up different on every tank. If there are air bubbles under it at the wrong place its going to blow off and hit the shuttle. Most of the time its non fatal but it can be fatal anytime. The foma that did fly off was heading in the general diretion of the leading edge though it didn't get close.....this time. Its always a gamble.
- Prior to the Shuttle U.S. spacecraft had all the most delicate and important manned part of the stack, that had to survive the whole mission, and keep the crew alive at the top of the stack. Debris and ice rained down all over Saturn V but there wasn't anything fragile to hit and the stuff on the bottom is ditched early and isn't around for reentry. The crucial heat shield was totally protected since is was between the capsule and the stage below so it couldn't get damaged by debris. All the new designs return to putting the vehicle at the top of the stack because that is a good design. Handing it on the side of a cryo tank was a now fatal mistake.
The shuttle by contrast has a massive, very fragile array of heat shields all of which are out in the open and most of which are right next to the ET which sheds debris and or ice every flight. Its an accident waiting to happen. Its a crap shoot if debris falls off in the right place to strike the wrong place on the shuttle. In Columbia it did. There are odds it will happen again, so now NASA knows it has to spend half of every mission just checking to make sure a debris strike or a faulty tile isn't in the wrong place, and it can't fly any place but the ISS in the event the roll snake eyes again and get damage to the heat shield in the wrong place.
@de_machina
Or why not reinforce the bottom and leading wings of the orbiter with some material strong enough to deflect any foam strikes, but can burn off harmlessly on re-entry, exposing the thermal tiles under?