It goes deeper than that - they have to individually inspect every tile after every mission, and due to the nature of ceramics that isn’t possible to do with total reliability. Basically you’re betting the lives of the crew on a rather fragile, easily damaged and almost impossible to inspect layer.
Incidentally, it doesn’t have to be foam - a micrometeorite, space junk or possibly even a birdstrike could do similar damage. The entire philosophy of using tiles is at the root of a large chunk of the problem, and that in turn is related to the blunt body design of the orbiter.
Would you get into a car if you knew that there was a 1 in 50 chance it would kill you on every journey? That is what the shuttle does.
Come to think of it, as far as I’m aware there have been three sets of fatalities related to the US space programme - the Apollo 1 launchpad fire and the two shuttle crashes. This despite the earlier Mercury and Gemini programmes being essentially ICBMs with a man stuck on the top - and not designed from the ground up as man-rated systems with all the safety implications.
The Shuttle can only make any sort of sense if it is possible to inspect it quickly and cheaply between missions. Since that is by design impossible, there is no economic or other rationale for the Shuttle at all. This should have been very obvious earlier in the design programme.
Edited repeatedly to deal with double post
Once again, it was meant to be cheap and re-usable. Each Shuttle was supposed to do 100 missions in ten years and then be replaced:
There is a good article with many additional references here:
http://www.nationmaster.com/encyclopedia/Space-Shuttle-program
How many people are killed in car accidents everyday or killed in aircraft crashes yearly?? A shit load…but people still get in the car and drive. The astronauts know the dangers and are lined up to go, so they think its worth it.
Were talking shuttle not Apollo or Gemini. :?
Per journey (the relevant statistic as both aircraft and spacecraft are very safe indeed in the cruise condition), modern aircraft are something like 10,000 times safer than the Shuttle. Even cars are something like 1,000 times safer, despite being operated by complete idiots most of the time.
The point I was making (which you missed) is that statistically Gemini and Mercury were SAFER than the shuttle, and depending on how you work the stats Apollo was either roughly as safe or much safer. Since Apollo was cheaper and had a higher payload capacity, exactly what is the point of the shuttle again?
Were talking who controls space will be the #1 power and now it has gone to the effectiveness of the space shuttle.
I think the dangers are acceptable being that There were 42,800 traffic fatalities in the USA last year alone not counting the rest of the world. When the foam problem is fixed the shuttle will be back on track, weather its over budget or not its still going to happen, that just means less to give to other nations. :?
IM not sure what 113 Apollo spacecraft would have cost and I don’t think it can hold more than 3 Astronauts, maybe it could be modified to hold more…I don’t know.
On a personal note…I love the Apollo ships, I would love to see more launched. 
Can’t see it being a problem - from memory the throw weight of Apollo to low earth orbit is substantially greater than the payload of the shuttle, so the excess could easily have been used to increase the crew size. However, throwing large crews into orbit is pretty inefficient and dangerous - it’s inherently safer and cheaper to keep them up their as long as possible, and you get better data too. Hence the ISS.
Cost is a major reason to go back to something like Apollo - while the shuttle is nominally reusable, the cost of inspecting it each time and the additional cost of all the weight of the orbiter you have to loft (best part of 100 tonnes from memory :shock: ) means it’s actually cheaper to go to disposable rockets. The only expensive bit that the shuttle saves is the main engines anyway - most of the rest is actually pretty cheap to manufacture.
Is there a better way than the shuttle?? IM sure there will be, if you dont try you wont fail.
If you want to do reuseable, you’ve got to do it properly. That means engines that can work in both rocket and air-breathing mode so you can come in under power and hence with much reduced air frictional loading (as I understand it anyway). This could be done today by brute force engineering (the technology has been around 20 years or so - since at least the HOTOL scheme) today, or if you wait 5-10 years we should have some form of scramjet working. That’s a lot lighter and more elegant, but there is no reason we couldn’t do without it.
If you don’t, disposable rockets are still a much better solution than the current shuttle. The US has IIRC a couple of designs, both of which are pretty good and substantially cheaper than the shuttle. One of them can IIRC also lift substantially more.
If you want to do reuseable, you’ve got to do it properly. That means engines that can work in both rocket and air-breathing mode so you can come in under power and hence with much reduced air frictional loading (as I understand it anyway).[/quote]
In the process of packing to move away at the weekend, so can’t get my hands on my notes, but AFAIK, the benefits of such a hybrid engine are actually on the way up - not the way down. Getting back down isn’t really the issue if you’re starting from a clean sheet of paper and give into the urge to design something which is either a better shape or re-enters less quickly - and thus hot than shuttle. I seem to remember the term “wave riders” from somewhere. :S Needing engines to get down again is actually not the first road you want to go down - it means you have to haul all that extra fuel up there!
The benefits from a hybrid engine are that for as much as the flight as possible, you are scavenging reaction mass from the atmosphere. A pure rocket is hauling ALL of it’s reaction mass around all the time (EDIT - and worse still, the structure to contain it in… which is why we end up with staging which is hardly good for reusables!). An air-breathing engine like a turbojet can just take the fuel. That means you can take more payload up instead, and/or carry more fuel and oxidiser for those parts of your ascent where there is insufficent air to breathe. Additionally, if you also use wings to a greater or lesser extent, for the air-breathing part of your ascent, you take the burden of lifting against gravity off your engines and hence your fuel supply, and put it onto aerodynamics lifting surfaces. It takes longer and incurs a drag penalty, but CD is less than CL so net gain.
This could be done today by brute force engineering (the technology has been around 20 years or so - since at least the HOTOL scheme) today,
Look up SKYLON. HOTOL may be dead and buried, but the idea sort of lives on in SKYLON. Combined air-breathing/rocket engines. Small wings. Fully reusable. Unfunded.
obviously china is the fastest growing country, and they have the largest population in the world. but, almost all of their population is smushed into the more inhabitable eastern part of china. the eastern part is smaller then the east coast of the united states. so china now has over a billion people smushed into a tiny space, this obviously causes crowding. china is also a semi communist country who violates alot of human writes. they have alot of people to feed, and in a time of war, when the world stops trading with them, how are they going to feed their people? also, the average income per family in china is less then half of that in the US, there are millions and millions of people livining in poverty, and there are alot of job oppurtunities, but not many high paying jobs.
now i am not saying that china is not going to be the next super power, but i just think that it is going to be a bumpier road for them then people realize.
Hi Fanatic, Ive been looking for a site that has the average income for a family in China… a project IM working on. Could you post your source please?? Thanks
Firefly wrote
Once again, it was meant to be cheap and re-usable. Each Shuttle was supposed to do 100 missions in ten years and then be replaced:
So in actuall fact, a shuttle fleet of just Atlantis and Discovery should have done 200 flights by now!!!
How big is the fleet, including the ones that have crashed?
Atlantis,
Challenger,
Columbia,
Discovery,
Endeavour ? Not sure about this one.
Enterprise ? This might have been made up for Star Trek, There is a picture of a shuttle in the background of one of the movies, along with various other Enterprises like the carrier and the Wooden ship.
Regards to China population, they sort of dealt with that themselves. But with results that had not been predicted!!!
One child only…In a nation where having a son is important to the continuance of the family.
Lots of infanticide towards female babies. So they can have a boy, to bring a girl to the family house and the parents can be looked after by the boys wife.
Whoooppppssss!!!
China now has a generation where boys heavily out number the girls!!!
Also Mike.m.
Dead sattelites are often put in to junkyard orbit, far from earth.
Certainly the Russians were fond of driving sattelites that may be sensitive in to the atmosphere - resulting in its destruction.
Your observation that the shuttle could get further out than it does, is valid. The shuttle is probably capable of going slightly further out BUT space is quite heavily monitored.
If any one puts up a spacecraft, then it is generally heavily observed by countries, that may not even be capable of sending a craft up. So they would know, what the shuttle was up to. Comms can be monitored also.
America might be the only country to play up there, but it is not a private playground by any means.
“Catching” a sattelite is a very dangerous and difficult evolution. This is why most sattelites up in space are not repaired. Many comms satelites that I know of, usually have one or more systems down.
There is one COM SAT that I can’t think of the name that is out of control power up there, and so it is used by anybody!!! It just moves around the sky, and if it is above you, you use it, when it moves out of range, then you stop.
Otherwise it is fully functional.
Why wouldn’t they repair this satelite? Or the number of others that have been degraded by time, radiation and debris strike?
Sorry mate, but your idea of grabbing satelites seems abit “Area 51” to me.
A single country invade the USA and succesfully dominate it would be quite hard at the moment… the USA havent really been a superpower for that long, they only have had so much power since the Second World War but when you say single country could you also mean perhaps continent ?
If the world helped eachother we could inevitably take the USA.
[quote="1000ydstare"Why wouldn’t they repair this satelite? Or the number of others that have been degraded by time, radiation and debris strike?
Sorry mate, but your idea of grabbing satelites seems abit “Area 51” to me.
[/quote]
Your obviously an EXPERT on space as well. :shock: As I said the 3rd shuttle was much more heavy than the previous two. WHY…who knows, I think they brought something down you dont…OKAY thats your opinion.
If the US would go after a Russian sub that sank WHY wouldnt they go after a satellite?
I have been giving this a bit of thought, and to be honest the old Glomar Explorer did feature in my thought process.
Obviously the Americans pulled up a sub, to the chagrin of the Russians, but that’s my point as well. Everyone knows about it.
If an object as small as an 8in spanner can be tracked in space (which is currently the smallest piece of debris to be tracked) then a shuttle couldn’t do a great deal with out being spotted.
I work with Satelites quite often in my work, specifically the comms birds, so yes I have had a brush with various aspects of sattelites including for some bizarre reason how to launch them and other things like their orbit paths. I also studied the GPS system.
I don’t doubt that the shuttle landed heavy but surely if it did on only the 3rd operational sortie, could it not be a test to see how heavy a shuttle could land?
Rather than the result of a potentially dangerous and extremly tricky manouvre that NO one has noticed or at least reported on?
The bringing back of ANY satelite, even an American one, would have caused some sort of comment.
By the way, how did you see the shuttle land? Not disbelieving or any malace intended, just wondered what you do.
We know about the Sub now…I dont think anyone did when it happened.
Very possible…maybe it went up heavy and came down heavy, maybe it was a test (they didnt say anything about that test) or maybe it wasnt 8)
I was a firefighter in the USAF for 8 years and for the last 6, I was stationed at Edwards, when the shuttle lands the AF Fire crews provide standby and get very close.
Not a bad job Mike.M!!!
Can understand why you and your crews would be extremely close when the shuttle comes back down.
Like I say, I use Sats all the time as a communications specialist in the British Army. So it is a an area that I have been trained in, although I have never been close to a space vehicle myself.
Another, slightly off the shelf, result in a sattelite disappearing would be “burgler alarms”. It would not take much in the way of explosives to damage the craft recovering a satelite.
I really believe the removal of a satelite, would not go unnoticed. You can actually log on to a Britsh site and view what is up there, there is a similar NASA site. Never seen the spanner on screen but I’ve been told it’s up there, moving at 10,000 miles an hour!!!
or similar.