Space Shuttle vs foam?

Question

With a craft designed to with stand heat of re-entry why is foam being such a problem? Any "rocket scientists" out there?

Answer 1

Ceramics are brittle

Ceramic tile is glued to the aluminum frame of the space shuttle to let it re-enter the atmosphere of the earth and survive the huge heat. The space shuttle Columbia was destroyed because there was a hole on the wing’s leading edge and that part goes directly into the air stream so the temperatures are the hottest at that point. Once the tile failed the heat entered the wing, melted the aluminum frame in seconds and ripped the wing off. The shuttle started to tumble and the force of re-entry smashed into pieces that rained down over Texas.

The shuttle is a great compromise between weight, cargo, and lift. Rockets are not very efficient and lifting with them is expensive. The quartz windows on the original shuttle design were too thick. My father worked as a contractor for NASA and he said they had to shave some of the quartz off the windows to save weight. When weight is this much of a problem it will make the shuttle too heavy to reinforce the ceramic tile, say with titanium fibers, so give it structural strength.

Face it ceramics are just baked clay with certain additives and methods different things can be made, but the basic material binding it together is still clay. Clay can be strong and Egyptian clay pots have survived to this day, but not if you put a lot of force on them; especially if it is the force of a sudden shock. When the shuttle takes off it is moving at least 3G, so that tiny shred of foam had to be moving at over 65 ft/sec. That is a lot of force; if it had been a chunk of denser ice then the damage would have been worse. The purpose of the foam is insulation, to keep the cold liquid fuel in the main tank cold and ready for use and to prevent ice from forming. If the tank did ice up then the danger would be greater.

Again thanks to weight considerations the foam isn’t that strong or reinforced. A hail storm was enough to pock market the tank like the craters on the moon. These holes would cause turbulence increasing heat and tearing off more foam so the foam had to be repaired. In the latest case a piece of foam hit the shuttle near a landing gear door. The 3” gouge goes all the way through the tile. Spare tiles aren’t carried on board because each piece is custom made and shaped for that part of the shuttle; no two tiles are the same. So the astronauts carry a goo that can be squeezed into the hole or they can stuff it with foam and hope it works. The space walk is dangerous because any space walk is dangerous and if the astronaut or the space station’s arm hits the shuttle more damage could be done. In the cold of space the ceramic tiles are even more brittle; so this is a real problem and dangerous to boot.

The damage may not be enough to cause a Columbia disaster; shuttles have landed safely with damaged tiles before. In fact the tiles form a great problem. Early in the program the glue failed and whenever the shuttle files a few tiles are damaged. A spacecraft is a precision instrument, finely crafted to exacting standards there is little room for failure.

NASA has extended the space mission by 14 days, which thanks to the new construction on the space station is possible. The new solar panels allow more power to be used to keep the space shuttle operating longer. Cooling and other systems are constant drains on the batteries and the fuel cells have a limited life. Chances are very good that the astronauts will make a space walk to repair the shuttle. The repair will be hard, because the space suits are so clumsy, but the astronauts have trained for that. The damage is minor enough and in a less critical area so that the shuttle is expected to have no problems landing. But, this shows a problem that exists with the aging space shuttle fleet. NASA plans on taking them out of service soon, 10-20 years before they have a replacement. So we will have to rely on the Russians to restock and change the crews.

The Apollo like replacement program is called Orion. It will be a capsule and will be unable to carry any large segments or big supplies. After Apollo 17 the US lost its drive to go to the moon and Mars. We also lost the scientific technology and skills to build the spacecraft. That’s why Orion, isn’t a copy of Apollo, but is being redesigned from the ground up. We also have to redo a lot of the previous work because in almost 30 years all the records are lost or too hard to find. If we had kept the space program in operation then we wouldn’t have that problem.

The space station has a finite lifespan. It is under constant bombardment by debris from space and from old satellites. Also its technology is dated. Currently we can replace the shuttle, although the current shuttle fleet wouldn’t survive the number of flights required. When the shuttle is retired then we will stop working on that design, to improve it and we will fall behind in the technology. We won’t have the capability to build a replacement therefore we won’t be able to make major updates or repairs to the space station. The only hope NASA has is that private business will create a space program that can handle the job. But currently they are far behind NASA, like we were when Alan Sheppard made his first flight. No private manned spacecraft fielded by the private sector is capable of orbiting the earth. Most will just reach the edge of space, hang around for a few minutes and then return.

Private industry has the advantages of NASA’s knowledge and experience, but they will still have to repeat a lot of the work just to reach the point where NASA is today. That is going to take a lot of time and money.

Answer 2

At high velocities, even a straw from a broom could be lodged into a tree or telephone pole!
So it stands to reason that this would hold true in "foam VS shuttle" as well.
I think the bigger question is, why is this happening so frequently all of a sudden? The last few launches all seem to be cursed by this!

Answer 3

The tiles are light as a feather. I've been told that if you hold one in your hand you'd be amazed at how lite it is compared to it's size. They say it's like holding nothing and they are essentially glued to the aluminum skin of the orbiter. The tiles are great for insulating the aluminum frame from reentry heat but they are fragile and as the other answer said brittle and easily prone to damage.

Answer 4

It's only a problem now because NASA never decided to redisign the shuttles to insure these things could not happen.

Answer 5

It's because of the high speeds and acceleration involved. Even something lightweight can pack a wallop if it hits you at tremendous speed. Force equals mass times acceleration.

Answer 6

it damanged the tiles so it makes a possible reentry problem the shuttle that broke had the leading edge of the wing damanged by the fom