Since they’re so worried about bits falling off the external tank, why not simply put a net around it? Something like a fishing net, but extra-light - silk, maybe?
Would it burn up, perhaps?
I think everything would heat up too much, and would just melt the silk. So lets go with a steal net of some kind. Like a thin, strong meshed metal fence wrapped around the tank. This might lead to some drag problems though.
What’s the problem with it burning up? Surely all the net would need to do is protect the underside of the shuttle during lift-off?
Maybe a hard plastic covering that can be cast away in space would be a way forward?
Sounds like it would work, and would likely be cheaper then 1 billion dollars.
I should know how fast the Shuttle flies on liftoff, but I don’t. I do know that it’s very fast. Friction would be a problem, especially with a ‘rough’ surface like a net. The SR-71 actually expands about a foot in high-speed flight. I’m guessing a net would burn off on liftoff, creating more FOD.
My husband works at Goddard Space Flight Center for a NASA contractor. He’s not involved in the shuttle program, but by default, he hears lots of discussions that aren’t common knowledge. I asked him the same question, and he said weight is a major concern. Actually, I asked why they don’t imbed fibers in the foam to help hold it together, and said for the size of the area insulated, all additional weight adds cost to the launch.
I’m sure that’s not the only reason, but I expect it’s a still a significant factor.
I know someone who asked this exact question to someone on the Columbia accident investigation board. The answer is that yes, it would probably work. The problem is, it would be a major change and can have unintended consequences, some of which have been pointed out in this thread already. To certify the modified design for manned flight requires extensive testing. Designing the net and doing the necessary testing would take about 3 years and $1 billion.
Doesn’t this just exemplify all that is wrong with the shuttle program?
No need for a net.
How about they build a Shuttle that doesn’t have parts fall off?
Crazy, I know, but it’s possible.
We have the technology.
I think you are radically underestimating the difficulty of space flight.
A Net? You mean a net mounted on the external tank? One that stays on the tank all the way up? If so, I don’t think you are taking into account the immense drag something like that would have. The wires on biplanes, for example, were a significant source of drag. And the force on that net would be very large. It would have to be very strong. I’m not even sure we have the materials you would need that would stay on the vehicle until the foam problem was gone. That means a net that can sit out in the windstream at multiple mach speeds.
So giant panty hose is out too, I suppose.
How about a really really big condom?
I’m not so keen on having all that condom lube on our spacecraft. Since it’s all, like, pristine…
I don’t suppose painting it, like on the first couple of shuttle launches, would do a whole hell of a lot of anything?
Heeey, what’dya know. According to wikipedia:
:dubious:
Not to sound cold hearted…but if that’s the case, if it’d help the shuttle before it’s replacement comes around, I think maybe the atmosphere can take one more for the team.
No - only far enough to ensure the safety of the shuttle.
So NASA didn’t design a new tank in the 2-1/2 years that the shuttles were grounded because it would have cost too much but they changed one of the key materials and never looked back.
Pieces of foam have broken off at Mach 2. That’s why that light little foam can do so much damage. You’d probably have to keep the net at least until the point of max pressure, which means the most extreme loading possible. Then if you’re going to shed the net, you have to worry about THAT hitting the shuttle. It’s not feasible.
I wonder if they could use the freon just on the side of the tank that is next to the shuttle?
That way you don’t use as much freon and you still get the protection. After all the foam on the other side isn’t going to hit the shuttle.