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bloke wrote:p.c. program to discontinue the use of freon

You might be getting your politics and your science confused.

It was probably a Fortran program, they're engineers, after all.

bloke wrote:true or false?

The problems with cracking foam on the shuttle fuel tanks begin with a p.c. program to discontinue the use of freon (or a like substance) in the manufacturing process of this foam.

http://www.spaceflightnow.com/shuttle/s ... 0703crack/

bloke "D.P. might know the answer to this."

Do you have a source for this? The news story said nothing about how the foam is manufacturered.

But I rather doubt it. There are excellent refrigerants to replace freon (NOT R-134), including highly refined hydrocarbons such as propane. In fact, hydrocarbon refrigerants actually work better than freon. I would think any industrial refrigeration system would be able to work as well now as when freon was used. There's a whole other batch of conspiracy theories about why hydrocarbon refrigerants are not more widely used--something about DuPont's lobbying power, etc.

Rick "who uses HC-12a instead of R-12 in old-car AC systems" Denney

For what it's worth, the foam that did in Columbia was the CFC-based product (made with Freon), so the issues pre-date the switch in foam composition (chunks of Freon-based foam also fell off on previous launches without doing serious harm). Would that the problem were as easy to fix as going back to the old product.

bloke wrote:

WoodSheddin wrote:You might be getting your politics and your science confused.

Not as long as I admit to not knowing the answer, and am trying to get a truthful answer.

If that is the honest intention, then I stand corrected.

I see the shuttle situation and the NASA types as being extremely nervous that their programs are going to get axed so they have reverted back to the same cautiousness which was used when the shuttle program first started.

There will ALWAYS be risks involved with strapping 7 people to the top of thousands of pounds of supercooled explosives, attaching a couple of the worlds largest solid rockets to the side, lighting the whole thing on fire, and sending them into an environment without air. Have them continuesly fall around the earth at several thousand miles per hour then when they do finally start to fall back to the surface, surround them with temperatures so hot that PLASMA is created. Once they make it past those trivial obsticles, have them glide back without any engines and no chance of an aborted landing and have them touch down at one small runway somewhere on the planet Earth which was aimed at while traveling several thousand miles per hour just a couple of hours earlier while they were still falling around the planet.

Most of the men and women who undertake this mission are military and have dealt with risks their entire careers while flying combat missions in several hot zones around the world. They understand the risks involved and insist on agressively volunteering for them and even heavily competing for them not just for career advancement, but because they believe in the human need and desire for space exploration.

While I don't invite death on nearly anyone, I don't believe an entire program should have been grounded for 3+ years because of a mission failure. Space exploration is vital.

So what does the Shuttle really accomplish? It's far more expensive than other technologies for putting payloads up in the sky (last I heard, about $1.3B per launch), based on a 40-year old flawed design and subject to damage by woodpeckers (true!). And the shuttles themselves were designed with a 10-year operating life. We're keeping the program going with chewing gum and baling wire.

There have been other, better designs, such as SSTO, SDLV, etc. that have been cancelled when moods have shifted.

You can find my source in:

http://t2www.nasa.r3h.net/columbia/caib ... DF#page=64

Section 11.3 details the foam history if you want the gritty details.

Yes, it is absolutely a crying shame that we haven't built a better spaceship! (or gotten out of the way and encouraged private parties to do so.)

WoodSheddin wrote:There will ALWAYS be risks involved with strapping 7 people to the top of thousands of pounds of supercooled explosives, attaching a couple of the worlds largest solid rockets to the side, lighting the whole thing on fire, and sending them into an environment without air. Have them continuesly fall around the earth at several thousand miles per hour then when they do finally start to fall back to the surface, surround them with temperatures so hot that PLASMA is created. Once they make it past those trivial obsticles, have them glide back without any engines and no chance of an aborted landing and have them touch down at one small runway somewhere on the planet Earth which was aimed at while traveling several thousand miles per hour just a couple of hours earlier while they were still falling around the planet.

Most of the men and women who undertake this mission are military and have dealt with risks their entire careers while flying combat missions in several hot zones around the world. They understand the risks involved and insist on agressively volunteering for them and even heavily competing for them not just for career advancement, but because they believe in the human need and desire for space exploration.

I'm sorry, because I'm sure I have this story wrong, and don't remember where I read it, but I always loved it, so-

One of the early astronauts was asked if he felt nervous waiting to be shot into space. His reply- "I'm strapped to several million dollars worth of intricate and explosive material all provided to the government by the lowest bidder! HOW WOULD YOU FEEL?"

The latest from Cape Canaveral



Notice the missing chunk of foam. The danger will be the possibility of pre-launch ice build-up. A chunk of ice getting loose during launch can do a lot of damage.

bloke wrote: I wonder if disposable rockets (60's technology with Y2K computer technology) would be safer and more cost effective.

Probaly. Here are the numbers I found after a lot of digging (LEO=Low Earth Orbit, GEO=Geosynchronous Earth Orbit):

Space Shuttle:

$8,000/lb to LEO; $200,000/lb to GEO

Rockets:

Between $1,820/lb and $15,000/lb to LEO depending on launch vehicle. ~$60,000/lb to GEO for a medium sized rocket. Doubltess the Russians would want less that that--I couldn't find their rates.

Big rockets carrying heavy payloads tend to cost less per pound to lift a payload into orbit.

The cost-analysis study was conducted for an overly optimistic NASA by an outfit called Mathematica. Apparently, some unrealistic assumptions were made.

The business with the tiles is sort of an interesting case. From what I've found out, bits of the tiles have been flaking off since the first shuttle lanuch. Given the density of the material (I've held a tile in my hands--it's about as hefty as styrofoam), NASA concluded that it posed no problem and decided to live with it. From an engineering standpoint, that wasn't a particularly sound decision, apparently.

Chuck(G) wrote:

bloke wrote: I wonder if disposable rockets (60's technology with Y2K computer technology) would be safer and more cost effective.

Probaly. Here are the numbers I found after a lot of digging (LEO=Low Earth Orbit, GEO=Geosynchronous Earth Orbit):

Space Shuttle:

$8,000/lb to LEO; $200,000/lb to GEO

Rockets:

Between $1,820/lb and $15,000/lb to LEO depending on launch vehicle. ~$60,000/lb to GEO for a medium sized rocket. Doubltess the Russians would want less that that--I couldn't find their rates.

Big rockets carrying heavy payloads tend to cost less per pound to lift a payload into orbit.

The cost-analysis study was conducted for an overly optimistic NASA by an outfit called Mathematica. Apparently, some unrealistic assumptions were made.

The business with the tiles is sort of an interesting case. From what I've found out, bits of the tiles have been flaking off since the first shuttle lanuch. Given the density of the material (I've held a tile in my hands--it's about as hefty as styrofoam), NASA concluded that it posed no problem and decided to live with it. From an engineering standpoint, that wasn't a particularly sound decision, apparently.

I think it's obvious that the present shuttle has not even come close to the original goals. An economically viable reusable space craft is probably years away from becoming reality. Some of you may remember the X-30 National Aerospace Plane that was to lead to an aircraft that would take off from a runway like any other aircraft and then be able to accelerate to escape velocity and enter orbit. This program was cancelled with the realization that we were only in the beginning stages of developing a hypersonic engine. Only recently have we successfully tested such an engine (SCRAMjet) and NASA engineers predict that we are perhaps 20 years away from a two stage to orbit manned vehicle.

http://en.wikipedia.org/wiki/Hyper-X

I'm still waiting for them to launch Bruce Willis on a one way trip to outer space.

But why would private industry really want to do it??? For the X Prize, there was a goal...$10 million and bragging rights. But for a company to seriously pursue space flight, there would beed to me some profitable gain in it. Selling rides into space? Fun idea, but an insurance nightmare. Plus, the cost for such a ride would still be very high (yes, industry could do it cheaper than NASA, but space flight still wouldn't be cheap.) Only a few very rich people would be able to do it, which makes it not a very profitable venture. The only way for a private company to profit would be to carry equipment into space for other companies. (sattelites, etc). I can see the big yellow "DHL" space plane now....

Whatever...


...the Shuttle's fun to watch






I just took these from my driveway!