According to this article, NASA may not launch another shuttle until they find a way to repair tiles in orbit. It seems to be a rather difficult task.
So here’s my question. Is there a lightweight material available that NASA could apply to the bottom of the shuttle to protect the tiles during launch? This material would burn up on re-entry, but protect the tiles during launch.
Thoughts?
That’s an interesting idea. The X-15 used an ablative coating for some of the flights that burned away with high temperatures. The only drawback was the color. No self respecting test pilot would ride a pink rocket plane so they painted it white after applying the coating.
Don’t know if a coating would have to be thick enought o adverse aerodynamic effects or too much of a weight penalty but it’s worth a look IMO.
I have heard that the Chineese use oak blocks on their re-entry vehicles. The oak carbonises and the carbon acts as an effective insulator. Sorry no cite.
Also as I mentioned in another thread, aperiodic Penrose tessaltion would reduce the zipper effect of tiles peeling off.
I’ve heard that too antiechinus but don’t know the veracity. Doesn’t seem obviously wrong. Unfortunately it wouldn’t work for the shuttle because of weight and aerodynamic concerns that a “blunt end first” reentry vehicle doesn’t have. I was thinking more along the lines of a protective coating that burned away completely during the early phase of reentry.
Instead of tiles, is there a substance that can be used to coat the shuttle in a single unbroken surface? In the 30 or so years since the shuttle was designed surely some material has been discovered or created? The tiles concept seems archaic.
Revtim, IANARS*, but I’m sure that the gaps between the tiles are there to act as expansion joints. Any unbroken surface that big would expand and crack when exposed to the heat of reentry, and the surface would still be susceptible to impact damage.
*(I am not a rocket scientist, and thank you for the chance to use the phrase!)
Because of the inherent fragility of the tiles, there is always some damage following each reentry. Individual tiles can be easily replaced, whereas a monolithic heatshield would be prohibitively expensive to replace just to repair localized damage.
This is true. The aluminum structure of the wing has much greater thermal expansion than the tiles. As the wing heats up, the tiles have to be able to move slightly further away from each other, so they use a flexible bonding material to fill between the tiles. Each tile also needs to be bonded to the wing witha flexible nomex layer to keep thermal expansion from cracking the wing-to-tile bond. A single solid layer of heat-protective material would crack apart when the wing heated up.