NASA Power Washes Space Shuttle

[newlook 265]

A new neighbor just moved in next door who is active duty Air Force. His last duty was with NASA. After finding out that I owned a pressure wash business he went on to explain that NASA power washes the proctective tile on the Space Shuttle with water.

He stated that the shuttle is wheeled into a special hangar/bay which consist of 3 inch plexiglass all around the shuttle. This is for safety because of the amount of pressure coming from the ....I guess you could call it a rig. Anyway, he said that a computer operates the "rig" and hits each tile individually with one blast of water. He said that the pressure is so high that it actually makes a sonic boom in the hangar/bay each time it releases the blast. The water is traveling so fast that it measures between 2-3 g's when they do this.

Now that's a rig.....:)

Has anybody heard this before? I couldn't see why this guy would lie....he is a full bird colonel.

Oh.....we are power washing his house on Tues. :rolleyes:

[svp07 14]

Any chance of a pic? That would cool to see.

[One Tough Pressure 580]

Sounds more like water blasting rather than pressure cleaning.

[newlook 265]

I searched the internet for a pic....no luck on that.

Alan -- yea....I think it falls more into the blasting catergory. Interesting if it is true. Good to see ya!

[svp07 14]

Just a little point I'd like to make. I went to Clemson University for my undergrad and their Ceramics Lab worked on creating the tiles for the shuttle. I toured the lab and saw the tiles and also got to hold them. They are very strong but also very brittle. My question is why do they need so much pressure?

[Mike Williamson 198]

I imagine there's a reason for it...I can't see why they'd go to the expense of engineering such a rig if it wasn't needed. Imagine how much crap gets on those tiles by the time it gets back from a mission.

[One Tough Pressure 580]

Since they are on the Shuttle, we know they can handle some incredible pressure. I would also think that they would not want to put chemicals on the shuttle either, so if it is water blasting, I am sure that it serves a really good purpose.

[troyt 14]

My guess is that they are not so much as cleaning as they are testing for loose tiles. Like Alan said, one re-entry the shuttle goes from a lack of any pressure to high pressure, and if one falls off, not good. Blast them with high pressure water to see if they can handle the strain, then roll it onto the launch pad.

[One Tough Pressure 580]

I talked to a friend of mine who used to work for Lockheed. He said that the tiles are made of graphite, and when they need to clean them, they just replace the tile.

I like Troy's theory of testing for loose ones.

[Mike Williamson 198]

Your friend is crazy! They'd be replacing every single one of them after every flight...which they don't. They're re-useable. They're also damned expensive, and not made of graphite.

Here's something I pulled off the web, and a link to a CNN article that ran shortly after the Columbia was lost:

Here is a CNN article (Feb. 3, 2003) about the space shuttle tiles. It indicates that the tiles are made of a silica fiber compound, a material derived from common sand. The fibers are mixed with deionized water and other chemicals and poured into a plastic mold, where excess liquid is squeezed out. They are then baked in the nation's largest microwave, in Sunnyvale, California, and fused in a 2,350 degree oven.

This short NASA note written in 1997 indicates that their value is between $1000 and $4000, although they are not for sale.

A materials chemistry article states that "the tiles consist of fine glass fibers organized in an open cellular pattern, so that tiny spaces account for 95% of their volume".

Through his contacts with NASA, Harry Nelson, Director of the John Deere Planetarium from 1968 to 1988, acquired a couple of space shuttle tiles. The photo above shows one of them. It measures 15 x 15 x 6.5 cm. Its mass is 266 g so its density is 0.18 g/cm3.

The following paragraphs are from a book called "The Space Shuttle Operator's Manual" published in 1982 (ISBN 0-345-30321-0).

The black areas on the Orbiter are covered with blocks or tiles of varying size and thickness. These are called "high-temperature reusable surface insulation", or HRSI tiles. HRSI tiles protect areas where temperatures are between 650°C (1200°F) and 1275°C (2300°F). On Columbia, white tiles cover the forward fuselage, outer wing areas, pods, and the stabilizer. Called "low-temperature reusable surface insulation", or LRSI, these tiles are used where temperatures are between 370°C (700°F) and 650°C (1200°F).

Columbia's cargo-bay doors, fuselage sides, upper wing surfaces, and aft areas of the OMS pods are covered with a Nomex felt material. These areas remain below 370°C (700°F) during flight.

Altogether, nearly 32,000 HRSI and LRSI tiles cover Columbia. No two tiles are alike and each must be installed by hand. Both types of tiles are made from extremely pure (99.5%) sand. The sand is crushed into very small silica fibers and added to a ceramic binder. This mixture is fired to produce the blocks. They are machined to the proper size and shape, then the black or white coating is applied to their outer surfaces. The coating is made from a high-strength refractory glass.

An aluminum structure like that of the Orbiter flexes and bends slightly in flight. The TPS (thermal protection system) tiles covering the vehicle must be very close together. On the underside, the largest allowable gap between tiles is only 0.065" (1.6 mm). These glass-covered silica tiles are rather brittle and cannot flex or bend without breaking. To let the structure flex while keeping the TPS rigid, Nomex felt pads are sandwiched between the tiles and the structure. This way, the structure can move without moving the tiles. The pads and the tiles are attached with a thin layer of a room temperature vulcanizing silicon adhesive.

[One Tough Pressure 580]

Your friend is crazy! .

Quite possible!! I'll ask him again and see what his story is this time.