BR715-A1-30
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What Is The Deal With The Space Shuttle?

Mon Jan 07, 2008 5:01 am

After reading so much on it, as well as reading about Challenger, and Columbia, I have determined that to be the biggest hunk of crap I've ever seen in my life.

But the real reason I am making this post is to find out why NASA managers ALWAYS seem to give GO FOR LAUNCH, even when they KNOW something is wrong. In watching the documentary on Challenger, An engineer by the name of Roger Bouijolais (sp?) had warned Morton-Thiokol AND NASA NOT TO LAUNCH due to other mishaps in the SRBs. But they launched anyway.

Does NASA have a BAD case of Go-Fever? Why is it that they don't ever seem to care about anything except launching. Because they were so anxious to launch Challenger, when they were told not to, we lost 7 great Americans.

And then comes the Foam. It had been falling off of several missions for several years, and when they noticed it might have caused damage, they said "to hell with it, we can't fix it, so lets let them come back in, and see what happens." BOOM, 6 more great Americans, and 1 american-israeli GONE.
Puhdiddle
 
pilotboi
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RE: What Is The Deal With The Space Shuttle?

Mon Jan 07, 2008 5:16 am

Lately, they've had a lot more Not-Go-Fever. They've been taking extra special care of every single detail, down to the most tiny thing. Currently, the shuttle is delayed because of some external fuel tank sensors. It was supposed to go up a month ago but at the last minute was cancelled because of these sensors. Then after looking more into it, they decided to bring it back to the building and look more into it.
 
mham001
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RE: What Is The Deal With The Space Shuttle?

Mon Jan 07, 2008 5:21 am

If you look at the incessant number of delays throughout its history, I'm not understanding how any reasonable person could come the conclusion of the original poster.

edit: unless you draw those conclusions from an hour of television.

[Edited 2008-01-06 21:22:18]
 
Mir
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RE: What Is The Deal With The Space Shuttle?

Mon Jan 07, 2008 5:46 am



Quoting BR715-A1-30 (Thread starter):
But the real reason I am making this post is to find out why NASA managers ALWAYS seem to give GO FOR LAUNCH

They certainly haven't done so of late. The failure of a backup system that probably wouldn't have been needed stopped the launch several times, and delayed it several weeks. I've seen three launches since moving down to Florida last August, and on two of them I had to come back a second day because the first attempt got scrubbed for various reasons. Your statement is not only untrue, but rather unfair to the team of people who are dedicated to keeping the shuttle flying safely. There have been mistakes made, certainly, but to say that NASA has a desire to maintain the schedule at the expense of safety is just wrong - if they did, Atlantis would have already launched, and likely would have been back on Earth already having completed its mission.

-Mir
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SpruceMoose
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RE: What Is The Deal With The Space Shuttle?

Mon Jan 07, 2008 6:44 am

Quoting BR715-A1-30 (Thread starter):
In watching the documentary on Challenger, An engineer by the name of Roger Bouijolais (sp?) had warned Morton-Thiokol AND NASA NOT TO LAUNCH due to other mishaps in the SRBs. But they launched anyway.

Part of the frustration with both the Challenger and Columbia mishaps is that there were clear indications in both cases that something was wrong, but that information was not part of the 'go' decision. The gravity of the threat clearly got lost somewhere in the process.

Edward Tufte has some examples of really poor communication in both cases. Below is a link to an excerpt of an essay he wrote pointing out how the PowerPoint 'pitch' by Boeing led an insufficiently critical management team to the wrong conclusion:

http://www.edwardtufte.com/bboard/q-...fetch-msg?msg_id=0001yB&topic_id=1

(if that doesn't work, go to http://www.edwardtufte.com/tufte/powerpoint and click on the link to the sample from the essay)

As for Challenger -- see Tufte's book "Visual Explanations" (2nd edition) pp 26 and 38-53. On page 26 is the fax from Thiokol recommending launch. On pages 46-48 are Thiokol's awful graphical representations of their blow-by data, and on page 45 is the same data shown in a way that, if available to NASA management at the time, would have made postponing launch a no-brainer. The difference is really stunning. I apologize for not having online links for this, but if you search around Tufte's web site you may find them, or visit your nearest engineering library.

In both of these cases you can go back and find someone somewhere who knew something was amiss. But you can also find lots of evidence to suggest that the people making the final decision thought they were operating within safe margins. The point is, it's a lot more complicated than 'go fever'. I've only scratched the surface in my readings on this and I'm no expert, but the fact that the shuttle flies as much and as safely as it does suggests that the people in the program are smarter and more careful than you're giving them credit for. That fourteen people have lost their lives suggests that even the smart and well intentioned make terrible mistakes, that complacency kills, and that we've always got to scrutinize the evidence to make sure we're not being fooled and that we're not fooling ourselves.

-SpruceMoose

[edited to clean up a little grammar]

[Edited 2008-01-06 22:53:15]
It flew at an altitude of six feet for a distance of four and a half feet. Then we discovered rain makes it catch fire.
 
Thorny
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 08, 2008 12:12 am



Quoting BR715-A1-30 (Thread starter):
But the real reason I am making this post is to find out why NASA managers ALWAYS seem to give GO FOR LAUNCH, even when they KNOW something is wrong.

Because nothing is 100% perfect. There is always something wrong... with everything. You have to decide what is an acceptable risk and what isn't, and unfortunately, that decision-making process broke down twice. It is marvelously easy to sit on the sidelines and say "they shouldn't have launched!". It is somewhat harder, of course, to make that decision beforehand.

A ship in port is safe, but that is not what a ship is for.

Quoting BR715-A1-30 (Thread starter):
In watching the documentary on Challenger, An engineer by the name of Roger Bouijolais (sp?) had warned Morton-Thiokol AND NASA NOT TO LAUNCH due to other mishaps in the SRBs. But they launched anyway.

Is there a point to bringing this up 22 years later? There's hardly anyone left in the Shuttle program or its contractors who was around when Challenger was lost. And that might partly be why we lost Columbia 17 years later.

Quoting BR715-A1-30 (Thread starter):
Does NASA have a BAD case of Go-Fever?

No. If they did, Atlantis would have flown last month, the Shuttle wouldn't have stood down after more foam problems on STS-114 in 2005, etc.

Quoting BR715-A1-30 (Thread starter):
And then comes the Foam. It had been falling off of several missions for several years, and when they noticed it might have caused damage, they said "to hell with it, we can't fix it, so lets let them come back in, and see what happens."

Reference? Who said this? It certainly doesn't appear in the Columbia Accident Investigation Board (independent of NASA) report.

The foam debris was a known problem, and had been occuring since STS-1. Fixes were in development after the STS-112 debris event was much worse than had been seen in many years (since STS-30) and had elevated the problem to a higher danger level, but it was still not believed to be a safety issue. The foam liberation and damage was widely believed (by both NASA and contractors) to be a maintenance issue, not a safety of flight issue. Even after Columbia was lost, it took a ground demonstration to show that fall foam really could punch a hole in the wing RCC panel. This was a gigantic shock to most NASA and contractor engineers.
 
zanl188
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 08, 2008 12:35 am



Quoting Thorny (Reply 5):
Even after Columbia was lost, it took a ground demonstration to show that fall foam really could punch a hole in the wing RCC panel. This was a gigantic shock to most NASA and contractor engineers.

The strange thing is that now everyone now accepts that foam fall is a bad thing, launching o-rings at a temperature outside of the experience base is a bad thing, and launching astronauts in capsule containing copious amounts of flammable materials and pressurized 100% O2 atmosphere is a bad thing. All 3 should have been obvious prior to the related accident and yet weren't...
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BR715-A1-30
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 08, 2008 12:40 am

Another question I have is the Challenger launched at 53 degrees (or less). Were the O-Rings not designed for FREEZING temperatures? I mean, 32 degrees Fahrenheit is freezing, so why couldn't they have designed the O-Rings to deal with even sub-zero temperatures?

Slightly off topic, but there have been times when my CO2 tank for my paintball gun cracked and fell off after removing it?

And haven't there been launches where the O-Rings survived even at below 50?
Puhdiddle
 
Thorny
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 08, 2008 2:27 am



Quoting BR715-A1-30 (Reply 7):
Another question I have is the Challenger launched at 53 degrees (or less). Were the O-Rings not designed for FREEZING temperatures? I mean, 32 degrees Fahrenheit is freezing, so why couldn't they have designed the O-Rings to deal with even sub-zero temperatures?

No, the o-rings were not designed to work at freezing or below. The ill-fated Challenger launch had to be delayed until air temperature rose above freezing on January 28, 1986. That's why launch was at 11:37am and not 9:30am. They could have been, but with most launches in Florida, low-temperature operation was not a priority for funding.

The problem is that the cold temperature contributed to the o-ring failure, but was not entirely responsible for it. The field joint design was just very deeply flawed and the joints were behaving in unexpected ways at ignition. The joints had been suffering o-ring damage and blow-by even in much warmer conditions. The lower limit of 53 degrees that the engineers were fighting for was based on the previous low temperature for launch... STS-51C a year before the accident. But NASA and Thiokol management saw the paperwork saying that the SRBs were safe down to 36 degrees and demanded the engineers provide data indicating otherwise, something impossible to do in only a few hours.

The design flaw was solved by adding a "capture feature" and a third o-ring to the field joint. O-ring temperature performance was solved by adding heaters to the joints to keep the rings at 80 degrees despite outside temperatures.

Quoting BR715-A1-30 (Reply 7):
And haven't there been launches where the O-Rings survived even at below 50?

No. But there have been test firings in Utah that cold. The joint heaters have solved the temperature problem for the o-rings.
 
redflyer
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 10, 2008 3:32 am

Quoting Thorny (Reply 5):
Even after Columbia was lost, it took a ground demonstration to show that fall foam really could punch a hole in the wing RCC panel. This was a gigantic shock to most NASA and contractor engineers.

I recall in one of the early press briefings after the loss of Columbia, one of the senior project engineers was asked if the ship may have been lost as a result of the foam shedding (this was after video was made public showing the piece that came off and struck the wing). The engineer (you probably recall who it was) stated pretty emphatically that he didn't think that was a cause of the accident. I remember vividly his comment that a piece of foam the size that was shown in the video had such low mass that it couldn't have done enough damage to doom the ship.

My point is that even the best engineers are sometimes surprised by results. I think it stems from the fact that engineers deal almost exclusively with "knowns" -- hard data. At the time, there just wasn't sufficient data for them to draw the proper conclusions.

[Edited 2008-01-09 19:33:45]
My other home is in the sky inside my Piper Cherokee 180.
 
Blackbird
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 10, 2008 3:53 am

To be honest, I think they should have replaced the space-shuttle with a space-plane back in the eighties.

It would be a hell of a lot easier to operate for one if you didn't have to point the whole thing straight up on that huge vehicle that takes it out to the launch pad (That thing for one is gigantic and probably guzzles fuel to produce the power it does -- oddly nobody ever factored the fuel burn that gigantic machine must burn into the equation.) and instead just start her up on the tarmac and taxi her to a runway and takeoff. It would also be a lot easier to make a powered landing than make a crazy gliding landing on the runway. Additionally, there would be no need for booster rockets, no need for a gigantic fuel-tank that's actually bigger than the spacecraft itself that ends up burnt to a crisp and is not re-used (That tank is the only thing that isn't re-used to my knowledge).


Andrea Kent
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rwessel
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 10, 2008 4:13 am



Quoting Blackbird (Reply 10):
It would be a hell of a lot easier to operate for one if you didn't have to point the whole thing straight up on that huge vehicle that takes it out to the launch pad (That thing for one is gigantic and probably guzzles fuel to produce the power it does -- oddly nobody ever factored the fuel burn that gigantic machine must burn into the equation.) and instead just start her up on the tarmac and taxi her to a runway and takeoff.

The crawler burns about 350 liters/km, and it's only six or seven km from the VAB to the pad (depending on which pad). IOW, the fuel burn for that part of the trip is utterly insignificant.
 
Thorny
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 10, 2008 5:02 am



Quoting Blackbird (Reply 10):
To be honest, I think they should have replaced the space-shuttle with a space-plane back in the eighties.

Space-planes seem to be the worst of both worlds. If you want to go into space, it is best to get out of the drag and heat-inducing atmosphere as quickly as possible (that is what the Shuttle's Solid Rocket Boosters are for... accelleration to orbital velocity is mostly the function of the Main Engines over the succeeding six-and-a-half minutes.)

In any case, a space-plane (X-30) was attempted beginning in 1986, it was cancelled in the early 1990s after billions of dollars spent and lots of "gotchas" and "uh-oh's" thwarted progress. The technology simply was not, and still is not, there. It was suggested then and is now crystal clear, that we should have undertaken a series of much smaller, much less ambitious test vehicles (smaller X-planes) to get the various technologies (and there are many needed) up to what we need for a full scale space-plane. Today, programs like Hyper-X (X-43) and HyShot are finally doing what we should have done 20 years ago.

Quoting Blackbird (Reply 10):
Additionally, there would be no need for booster rockets, no need for a gigantic fuel-tank

Instead of those, you need an engine that can work as both jet and rocket. (That's hard). And you need some way to convert gaseous oxygen from the atmosphere into liquid oxygen for your rocket. And it has to be small enough to fit on a plane. (That's even harder.) And you still need a big tank for the hydrogen, so the plane is still going to be huge.

Worse, since your space-plane has to rely on oxygen from the atmosphere, the plane has to fly in the atmosphere almost all the way to orbital velocity (Mach 25) where we have trouble keeping planes from burning up at Mach 3.

This is just a sample of the problems the space-plane program faced and ended up failing to solve.

Quoting Blackbird (Reply 10):
It would be a hell of a lot easier to operate for one if you didn't have to point the whole thing straight up on that huge vehicle that takes it out to the launch pad (

The Crawler looks like overkill with today's low flight rates (4-6 per year.) But the concept was designed for much higher flight rates (50 per year.) Under those plans, the mobile launcher concept makes much more sense.

Quoting Rwessel (Reply 11):
The crawler burns about 350 liters/km, and it's only six or seven km from the VAB to the pad (depending on which pad). IOW, the fuel burn for that part of the trip is utterly insignificant.

And the cost is indeed factored-in as part of the KSC infrastructure.
 
DfwRevolution
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 10, 2008 5:05 am

Quoting Blackbird (Reply 10):
To be honest, I think they should have replaced the space-shuttle with a space-plane back in the eighties.

Reagan instructed NASA to do precisely that. It resulted in an even more complex and more expensive vehicle that never flew: the NASP. What we should have done was realize that we bit-off more than we could chew with the STS program and take a few step backwards.

What we should have done before that was keep the U.S. manned space program flying on the Apollo CSM but with a more economical ELV than Saturn. And while doing that, we should have been testing more ambitions X-planes to test reusable space technologies one at a time, rather than loading them all onto a single project that never gets off the ground or never performs as promised (i.e. X-33 or STS).


Dang, beat to the punch by Thorny.  Wink

[Edited 2008-01-09 21:08:15]
 
TheSonntag
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 10, 2008 9:35 am

To me, it does not really matter to ask "what if the shuttle were replaced in the 80s", as the fact is that it wasn't. Instead, I think it is much better to look into the future.

Ares isn't flying yet, but maybe one should start with an outlook beyond the year 2025. What will we see beyond Ares I and V?
 
wvsuperhornet
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 10, 2008 10:19 am

When the first mission of an aircraft is to tae a full day to check to make sure your not going to blow up upon re-entry, then you need to retire it "Period"......
 
Thorny
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 10, 2008 2:28 pm



Quoting TheSonntag (Reply 14):
Ares isn't flying yet, but maybe one should start with an outlook beyond the year 2025. What will we see beyond Ares I and V?

Assuming the Ares project moves forward under the next U.S. President (Obama has already said it won't under him) then 2025 will be when Ares V is just getting into its stride. There will be incremental improvements... probably Ares V-B and Ares V-C eventually. Possibly niche vehicles like Ares III (Ares V with no upper stage, used as a tanker) and Ares IV (Ares V with Ares I Upper Stage).

Quoting Wvsuperhornet (Reply 15):
When the first mission of an aircraft is to tae a full day to check to make sure your not going to blow up upon re-entry, then you need to retire it "Period"......

That's just political CYA.
 
checksixx
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 10, 2008 2:38 pm

Bottom line is that anytime you strap people into/onto a rocket, there is risk. If anyone thinks there is some miracle system out there that is absolutely safe, they're living in a dream world. I don't mind when they no-go...it means people are doing what they're supposed to be doing. It means hopefully, we won't loose another vehicle or have any post launch aborts like with Challenger.

-Check
 
Pope
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RE: What Is The Deal With The Space Shuttle?

Fri Jan 11, 2008 3:24 pm

I think the condition of NASA is a national embarrassment.

It took man about 58 years between the first powered flight and the first space flight. It took 8 years between the first flight in space and landing a man on the moon. Now in the absolute best case scenario a manned space mission to Mars will launch in 2020 (don't hold your breath) meaning that at least 51 years will have passed between the time we first stepped foot on the moon and when we explored the next heavenly body.

The space shuttle is a perfect example of how unfocused NASA has become. The STS never achieved its goal of being a dependable reusable LEO launch vehicle. It costs orders of magnitude more in terms of $ and human lives than all the previous US space efforts and has achieved comparably little in return.
Hypocrisy. It's the new black for liberals.
 
Thorny
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RE: What Is The Deal With The Space Shuttle?

Fri Jan 11, 2008 9:16 pm



Quoting Pope (Reply 18):
I think the condition of NASA is a national embarrassment.

Yet NASA consistently is doing things that no other agency on Earth has ever done, such as successful Mars landers and probes to the outer planets.

Quoting Pope (Reply 18):
Now in the absolute best case scenario a manned space mission to Mars will launch in 2020 (don't hold your breath)

2030 at best. 2020 is return to the Moon.

Quoting Pope (Reply 18):
meaning that at least 51 years will have passed between the time we first stepped foot on the moon and when we explored the next heavenly body.

NASA can only do what it is funded to do. No U.S. administration or Congress has funded a human expedition to Mars. That includes the current one, which is funding only a return to the Moon (and barely funding even that.)

Quoting Pope (Reply 18):
It costs orders of magnitude more in terms of $ and human lives than all the previous US space efforts

No, it hasn't. Order of magnitude = multiply by 10. Apollo killed 3. Shuttle killed 14. Of course, Shuttle carries over twice as many astronauts per flight than did Apollo, and is closing in on an order of magnitude more flights to date. When compared to the number of flights and number of humans aboard those flights, Shuttle is only marginally more dangerous than Soyuz. Apollo's number of flights is so low that no statisically meaningful comparison can be made. (Although Apollo 13 came dangerously close to being fatal, and Apollo 6 would have aborted had a crew been onboard.)

Averaging over the length of the program, Space Shuttle costs about $500 million per launch. Titan IV was about $400 million each. Delta IV is around $250 million. But look at how much more versatile Shuttle is, with a crew of seven included in that cost. Saturn V was around $1 billion in 2004 dollars per launch. (Which is why LBJ and Nixon killed it in favor of something cheaper in the first place.) Shuttle didn't really increase costs over Apollo, but it failed to reduce them in any significant way.
 
TheSonntag
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RE: What Is The Deal With The Space Shuttle?

Fri Jan 11, 2008 9:27 pm

I would not call Shuttle an embarassment, more a symbol of different times.

Look how many test pilots died in the 1950s and 1960s. This would be completely unacceptable today, as the will to take risks has considerably decreased.

Apollo was extremely risky, nobody today would be willing to take this risk.

Shuttle is a symbol for this, it must be safe, everything must be checked, and thus, the smallest event makes launch impossible.

I think future missions must find a balance between shuttle and Apollo. Spaceflight IS risky. Nevertheless, the hardware must be more reliable than Shuttle. It is unacceptable that almost every Shuttle flight is delayed, while the (less capable, granted) Russians are able to fly on time.

So I think Ares is a good step forward. I hope the US doesn't cancel it. I am not an US taxpayer, but I would love to see the US back on moon with Ares V around 2020.

This is actually the biggest benefit for US foreign relations NASA can offer: Everybody wordwide is impressed and loves the US for their moon landing. NASA is popular. I hope future US governments keep this in mind when thinking about the budget.
 
Thorny
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RE: What Is The Deal With The Space Shuttle?

Sat Jan 12, 2008 2:16 am



Quoting TheSonntag (Reply 20):
Nevertheless, the hardware must be more reliable than Shuttle. It is unacceptable that almost every Shuttle flight is delayed,

Shuttle isn't quite that bad!

31.4% of Shuttle flights were launched on time. Another 24.7% launched late but still on the scheduled day. So about half of all Shuttle flights launched on the scheduled day.

Of the delays, 44.6% were due to weather.
 
cloudy
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RE: What Is The Deal With The Space Shuttle?

Mon Jan 14, 2008 7:55 pm

If NASA thinks Constellation, even with the whole shebang as originally envisioned, is going to excite people not otherwise excited by space they are under a serious delusion. Spend what we would have spent on constellation on unmanned projects and we could have a lot more exciting stuff. We could have sample returns from all over the inner solar system and perhaps the outer solar system as well. We could take a peak under Europa's ice. Eventually, we could have a telescope capable of not only discovering Earth sized worlds around other stars, but even imaging them. We could more easily try out new tech since in unmanned exploration you can afford a few losses. We wouldn't need the standing army the shuttle needs just to survive. Instead, We would need engineers to design the spacecraft, and more scientists to interpret the data we would be getting. These people would be doing exciting new stuff all the time.

Unmanned probes, rovers, etc. are what can excite people now and do serious science. They do real exploration, going places it takes years to get to and returning images + data about things no one has ever seen before. You can do so many more, different things then manned spacecraft can given equivalent levels of funding. This gap grows with every technological advance since manned space flight has to be conservative to be safe and cheap enough to do. If you want to excite people using something close to NASA's existing budget, unmanned space is the way to do it. Man on the moon 2.0 is not.

A lesson can be learned from the Mars rovers - NASA got more attention for that than they got for the space station - which costs literally a hundred times as much.

Bottom Line - Unless NASA can get a budget many times that necesary for Constellation, there is no use having a real manned space program at all. Better to have a placeholder program, or even nothing, and put the money into what people really want to see. When people unfamiliar with space look at rovers on mars, they think science and progress. When they look at the Space Shuttle and the Space Station, they think of their tax dollars going down the drain. Mostly , they are right.

Quoting Thorny (Reply 21):
Of the delays, 44.6% were due to weather.

I was under the impression, however, that the shuttle suffers more weather related delays then other launch vehicles because of the need to keep open abort options. The shuttle not only needs good launch weather, it needs good landing weather at the launch site and several other possible abort sites.
 
Thorny
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RE: What Is The Deal With The Space Shuttle?

Mon Jan 14, 2008 9:50 pm



Quoting Cloudy (Reply 22):
Unmanned probes, rovers, etc. are what can excite people now and do serious science.

Messenger is presently passing a few thousand miles over Mercury, only the second spacecraft (and the fourth flyby) to do so. 50% of Mercury is still unknown to humanity. Yet the popular media has barely even noticed. Compare with Scott "Too Tall" Paracynski's repair of the station's solar wing last year.

Humans in space are an order of magnitude more popular and interesting with the general public.

Robots are excellent precursors, but that is all they are: precursors. They tell us where to look deeper, but we need humans nearby or on the ground to actually do the looking. Exploration of the moon and Mars will both require a consolidated manned/unmanned effort to succeed, even the moon is too far away for telepresence to be realistic in difficult terrain or complex tasks. Robotic technology is always vastly oversold by anti-manned space critics. "Just send probes to do it, it is easier and safer!" That's true, but it is also vastly less productive. One of the Mars Exploration Rover mission scientists pointed out that what Spirit did in a month, a human could have done in a day.

Quoting Cloudy (Reply 22):
I was under the impression, however, that the shuttle suffers more weather related delays then other launch vehicles because of the need to keep open abort options. The shuttle not only needs good launch weather, it needs good landing weather at the launch site and several other possible abort sites.

Correct.
 
TheSonntag
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RE: What Is The Deal With The Space Shuttle?

Mon Jan 14, 2008 10:57 pm

Also, human spaceflight is more than just science, it is also a highly political issue. This isn't necessarily always a good thing, but certainly, the PR gained from being the first on the moon can hardly be topped again.

The Shuttle and ISS are not as spectacular, as they might seem to only do something Gargarin did in 1961, orbiting the earth. Yet they are a huge step forward for science, and international cooperation in space.

Being the biggest international civil project ever undertaken IS something spectacular. But I really think time has come for the next step. If we can live in orbit half a year, I would love to see a permanent moon station.

Whether we will live to see a manned Mars mission is still debatable. I hope so. And who knows, maybe we will see a manned mission to Jupiters moons in some centuries...
 
wvsuperhornet
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 15, 2008 10:27 am



Quoting Thorny (Reply 16):
That's just political CYA.

Yeah Ok!!!
 
nycbjr
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 15, 2008 9:30 pm



Quoting Thorny (Reply 16):
Assuming the Ares project moves forward under the next U.S. President (Obama has already said it won't under him)

and just what is he proposing to replace it with? alllow the shuttle to keep going? or stop man space flight in the US all together.. man is seriously delusional...
 
Thorny
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 15, 2008 10:15 pm



Quoting Nycbjr (Reply 26):
and just what is he proposing to replace it with? alllow the shuttle to keep going? or stop man space flight in the US all together.. man is seriously delusional...

He said he would delay Constellation five years to pay for beefing up Education. There were few other details. A five-year delay would effectively kill Constellation as the Shuttle-heritage workforce and manufacturing that (in the original plan, anyway) made Ares a cheap, straightforward replacement, would vanish and be impossible to reassemble five years later.

Sen. Obama took a little flak for that plan and has backed off on it somewhat, but it is clear where his sentiment lies: don't expect big things in space during his Administration.

I don't have a huge problem with killing Ares. It is a joke of a system (especially Ares I) that bears little resemblance to the "safe, simple, soon" promise on which it was selected. A "Direct" or EELV-based system now seems enormously more sensible. I'd like to see one of the candidates point that out and say "I'm in favor of Constellation, but let's do it the smart way, not this way." The "Direct" approach would cut development time and cost in half. The EELV approach would be a gigantic shot in the arm to the U.S. space launch industry, offering economies of scale that could well make them competitive against Ariane and SeaLaunch. Instead, NASA is building a one-use vehicle of its own that won't even be particularly good at that one use.
 
TheSonntag
Posts: 4303
Joined: Wed Jun 15, 2005 7:23 pm

RE: What Is The Deal With The Space Shuttle?

Tue Jan 15, 2008 10:30 pm

How much is Constellation actually under way? Is ist still possible to cancel it without losing too much money? I mean, sometimes projects have gone so far that it is cheaper to continue them than cancelling them.

And even if it could be cancelled now, this will not be on the agenda before the new president is elected. How far will Constellation be in 2009?
 
Curt22
Posts: 334
Joined: Sat Jul 14, 2007 11:43 am

RE: What Is The Deal With The Space Shuttle?

Wed Jan 16, 2008 12:07 am



Quoting Thorny (Reply 5):
A ship in port is safe, but that is not what a ship is for.

What a fantastic quote!

Much a more economical use of words compared to Teddy Roosevelt's "Man in the Arena" speech, but both the ship and this speech apply well to the subject of NASA critics.

"It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat."
Theodore Roosevelt, April 23, 1910
 
cloudy
Posts: 1613
Joined: Sat Apr 06, 2002 3:23 pm

RE: What Is The Deal With The Space Shuttle?

Wed Jan 16, 2008 3:14 am



Quoting Thorny (Reply 23):
That's true, but it is also vastly less productive. One of the Mars Exploration Rover mission scientists pointed out that what Spirit did in a month, a human could have done in a day.

I doubt he could do more than the hundreds or even thousands of rovers, etc. that could be sent for the price of getting him there, and all the scientists who would be kept working interpreting the data. There are MANY in the scientific community who think that way, my guess would be the majority. Many have to stay silent for political reasons, and to avoid controversy.

Another reason the manned space program gets less scrutiny than it deserves is that people realize this is not a perfect world. If the Democrats got rid of manned spaceflight, the money saved would go to social programs. If the Republicans got rid of it, they put the the money into the Pentagon. Both would throw bones to their constituents in the form of pork. Not much more would be spent on unmanned spacecraft. As bad as the ISS and Shuttle are, they are more useful then a bridge to nowhere. And any money taken from NASA could not significantly improve the defense department or the myriad of programs we have that claim to help the poor, or the deficit. It would be a drop in the bucket.

Quoting Thorny (Reply 23):
Compare with Scott "Too Tall" Paracynski's repair of the station's solar wing last year.

Humans in space are an order of magnitude more popular and interesting with the general public.

People are not excited by an airless rock such as Mercury, unless some significant discovery is made, and we don't have enough data for that yet. Mars missions get far more attention. So does the new Pluto mission. Messenger was much cheaper than the ISS program, even by some measures cheaper than a single shuttle flight even without payload. I doubt any informed observer would claim that if we spent all the money we spent on ISS and the shuttle on unmanned probes instead, we would have gotten a far greater return in both publicity and science. Apollo may be a different story, since we were doing more new things and a lot of technology we use in probes now was not available then. Even so, wait about 10-20 years and spend about a quarter as much money on sample returns, rovers, etc. and we probably could learn as much as we could have from Apollo. At least that is my Scientific Wild Ass Guess.

Again, no one disputes that manned missions are more effective than unmanned missions. But is it worth the hundred-fold increase in cost? Do you really get THAT much more science and attention out of it, considering just how many more things you can do with robots for far less money?

The march of technology works against manned spaceflight. Robotic spaceflight is getting cheaper and easier at a far faster rate than manned flight is. Every advance in CCD's, long distance transmission, etc. increases the amount of data you can get from unmanned craft. Better yet, unmanned space PROMOTES these advances at a faster rate. Anybody want to guess how much more mature nuclear/solar electric propulsion would be by now if the unmanned program had the same funds as Apollo? Or even the same as ISS?

If you want to see innovation, new technology, good science return for the money, real exploration, etc.
look at the unmanned space program. For pork, politics and political stunts look at manned space flight. If you could get a tenfold increase in NASA's budget, MAYBE it would be more efficient to send people. But it seems to me that for the money people are willing to spend probes are the best bet.
 
TheSonntag
Posts: 4303
Joined: Wed Jun 15, 2005 7:23 pm

RE: What Is The Deal With The Space Shuttle?

Wed Jan 16, 2008 12:23 pm



Quoting Cloudy (Reply 30):
But is it worth the hundred-fold increase in cost? Do you really get THAT much more science and attention out of it, considering just how many more things you can do with robots for far less money?

Maybe the question isn't "Is it really cost effective" at all. I think that the arguments pro human spaceflight are not really of economical nature, and shouldn't be. There is a lot of idealism in it, as well, travelling for the sake of exploration.

And as great a probe mission is (and I really thing it is extremely impressive that Voyager 1 is still able to communicate with earth, although it is so unbelievable far away, or that you can remote control mars rovers from earth, just to name a few achievements so far), this is not the same as having humans living there. "To boldly go where no man has gone before"  Wink
 
Thorny
Posts: 1508
Joined: Thu Jul 07, 2005 8:44 am

RE: What Is The Deal With The Space Shuttle?

Wed Jan 16, 2008 3:02 pm



Quoting Cloudy (Reply 30):
I doubt he could do more than the hundreds or even thousands of rovers, etc. that could be sent for the price of getting him there,

Your costs are a bit messed up here. Spirit and Opportunity, which spend most of their time charging their batteries, cost about $750 million, not including the mission extensions. The plutonium-powered Mars Science Laboratory, scheduled for launch in 2009, is budgeted at $1.7 billion.

Zubrin's Mars proposals in the '90s were in the $30-50 billion range. The quickly abandoned 1989 Space Exploration Initiative was projected at $500 billion, but that included a space depot (independent of Freedom/ISS), lunar exploration and bases, Shuttle II, a new Saturn V, nuclear reactors, a fleet of unmanned rovers, and just about everything else NASA could think of. There is no fundamental reason that human Mars exploration has to cost $500 billion. The spacecraft itself should not cost any more than the hardware that is the International Space Station (and it in fact may well look an awful lot like ISS) which cost around $25 billion. The new Saturn V-class launcher (already in development as Ares V) is budget at around $15-20 billion. The manned Mars Lander will cost perhaps as much as the Space Shuttle Orbiter to develop... around $8-10 billion in today's dollars. We're up to around $55 billion. We'll need things like nuclear reactors for the Mars Base, and improved life support systems. Neither of these will cost $50+ billion. NASA's basic plan is estimated at around $100 billion, and that already allows for a 25% overrrun due to unforeseen problems.

Where the idea of Manned Mars costing hundreds of billions of dollars comes from, I don't know. It is popular among critics, but doesn't seem based in any sort of experience or reality.

And yes, an astronaut (or four) almost certainly could have done more than hundreds of rovers. An astronaut wouldn't have spent a month stuck in a sand pit like Opportunity did. In that 30 days, an astronaut could have gone to 30 different places.

Quoting Cloudy (Reply 30):
Every advance in CCD's, long distance transmission, etc. increases the amount of data you can get from unmanned craft

As well as what you can get from a manned mission. That's the fact that manned space critics always ignore. While technology marches forward to make robots better, the technology for manned space is not standing still, either. The technology, in large part, is the same either way you go (manned or unmanned.)

But until we get "Data" in the 24th Century, a human brain on the scene is always going to be enormously more capable than a robot there. We need robots for places where humans can't go (like Venus or Europa), not for places where we can (the moon or Mars.)

Quoting Cloudy (Reply 30):
Do you really get THAT much more science and attention out of it, considering just how many more things you can do with robots for far less money?

It isn't at all clear you can do many more things with robots. In fact, the opposite is indicated. Opportunity travelled a few miles to Victoria Crater in a few years. That's how far Scott and Irwin travelled in three days on Apollo 15.

My position is not "cancel all the robots and send humans!". It is "send robots to scout the terrain first, then send humans to do the real work."
 
michlis
Posts: 696
Joined: Sat Jul 21, 2007 8:13 am

RE: What Is The Deal With The Space Shuttle?

Wed Jan 16, 2008 3:19 pm



Quoting Thorny (Reply 32):
There is no fundamental reason that human Mars exploration has to cost $500 billion.

Politics is always a fundamental in projects such as this, and my understanding is that the political atmosphere at NASA when the Space Exploration Initiative was drafted was such that everybody's pet idea was included as part of the Initiative and thus the balloned cost. I'm not NASA bashing, but it just seems that nobody took the affirmative step of just saying no to what wasn't needed to get the job done.

As for Zubrin, looks like our favorite Martian is stirring the pot again with a new book on how to get America off oil. You gotta love the guy.

http://www.amazon.com/Energy-Victory...UTF8&s=books&qid=1200496583&sr=8-1
If you know the enemy and know yourself, you need not fear the outcome of a hundred battles.
 
prebennorholm
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 17, 2008 12:39 am



Quoting Thorny (Reply 32):
Where the idea of Manned Mars costing hundreds of billions of dollars comes from, I don't know. It is popular among critics, but doesn't seem based in any sort of experience or reality.

 checkmark 

None of us living on planet Earth today will ever witness a manned Mars flight. It is too far away.

After almost 50 years of manned space flight we still get astronauts back in pretty bad shape from six months on the ISS. An multi-year manned mission is fantasy only.

Add to that the fact that landing and take-off from Mars demands a lot more energy than a similar Moon mission like Apollo. And that with life support for a year long journey back home. In the future we will see Mars sample return missions bringing ounces back. We will see live high quality pictures on TV and Internet. But not from a man held camera.

Should manned interplanetary flight one day become practical because of some presently unknown technology breakthrough, then it will most certainly become "prohibited" to land on Mars. The reason is that it would be unavoidable to "pollute" Mars with micro organisms from Earth which could for ever spoil the value of future scientific work on Mars. And Mars is for certain the most valuable planet (next to Earth) in our solar system for exploring planetary developments and especially their climatic, environmental, and biological properties.

For that reason a manned landing on an outer Jupiter moon will come before a manned Mars landing. Even if I cannot see why we should land a man a Jupiter Moon.

For all Mars landings since the very first 33 years ago we have been extremely cautious not to bring micro organisms to Mars in order to maintain Mars as the invaluable scientific treasure it is for investigating planet Earth. We cannot afford to spoil that. That's simply not compatible with a manned landing.

I am also very sceptical about future manned flights to our own Moon. There isn't much more we can learn about the Moon from the surface. That's also the reason why all Moon missions during the last few decades have been Moon orbiters, not landers.

Maybe some future Moon missions will not be for investigating the Moon, but rather to utilize it. One interesting thing could be an astronomical radio telescope on the back side of the Moon. It's the only place in the neighborhood of Earth where we can work on radio astronomy without "pollution" from Earth. It might require manpower to build such a radio telescope on the Moon, but when operational it would certainly be remotely operated via Moon orbiting data relays.
Always keep your number of landings equal to your number of take-offs
 
DfwRevolution
Posts: 8572
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RE: What Is The Deal With The Space Shuttle?

Thu Jan 17, 2008 10:12 pm



Quoting Prebennorholm (Reply 34):
None of us living on planet Earth today will ever witness a manned Mars flight. It is too far away.

I'd take that bet, although I am in my twenties. I'd even wager someone my age could be a member of the crew.

All the fundamental technology needed for a Mars mission exist today. Not all of them are in-service at the moment, but they have all been demonstrated repeatedly. All that holds us back is the cost of integrating and launching the spacecraft to do it. The only incentive for waiting is the hope of better technology that would reduce the total mass we would need to place in orbit. For example:

More reliable systems -> Less redundancy -> Less mass
More effective radiation shielding -> Less shielding -> Less mass
Nuclear upper stages -> Higher ISP -> Less mass

What comes next isn't that surprising. Anytime we need to place less mass in orbit, the program cost goes down. So for a manned Mars mission to take place, we need one of three things:

1. Politicians who just accepts the cost of the Mars Ship at mass X and the expense of launching it at cost Y.
2. Systems technology that lowers the Mars Ship mass to 3. Launch technology that lowers the cost Y to the point where the Mars Ship at mass X is acceptable.

While it won't happen in the next 2-18 years, a U.S. President in 2020-2030 could well have a space agency with the pieces necessary to prepare a Mars mission. We do have the money. In fact, both the Shuttle and ISS were funded by leaders who were not exactly pro-space. Can we discount #1? I don't think so.

At this very moment, there are a number of private space firms seeking to lower the cost of orbital access. If SpaceX is able to reuse their Falcon first stages, it would have a positive effect on launch costs. COTS could prove some important orbital technology, and the combination could (for example) allow NASA to refuel on orbit and reduce the number of heavy-lift Ares V they need for a Mars mission. Can we discount #3? Probably not, either.

The weakest point is #2, but it could certainly play a role in combination with the other two factors.

Ultimately, I understand some of the skepticism because some study always has put Mars "twenty years in the future," as far back as the 80s. But as Thorny points out, we have never said "go" to any of those ideas, so it doesn't follow to say that a Mars mission will always be twenty years out. This is different than say fusion, which always seems 50 years away despite billions specific research in that field.

We can really do it, and in respectable time, if we wanted to.
 
connies4ever
Posts: 3393
Joined: Sat Feb 25, 2006 10:54 pm

RE: What Is The Deal With The Space Shuttle?

Thu Jan 17, 2008 11:53 pm



Quoting Prebennorholm (Reply 34):
None of us living on planet Earth today will ever witness a manned Mars flight. It is too far away.

After almost 50 years of manned space flight we still get astronauts back in pretty bad shape from six months on the ISS. An multi-year manned mission is fantasy only.

1 - Don't be such a pessimist, and
2 - That's EXACTLY why we need nuclear propulsion for long-range missions.

Using NP for a non-Hohmann transfer could mean mission times are vastly reduced, consumable requirements are vastly reduced, and the stress on the human organism is vastly reduced.

Quoting DfwRevolution (Reply 35):
All the fundamental technology needed for a Mars mission exist today.

 checkmark 
Nostalgia isn't what it used to be.
 
highlander0
Posts: 163
Joined: Sat Sep 29, 2007 7:29 pm

RE: What Is The Deal With The Space Shuttle?

Fri Jan 18, 2008 12:11 am

If I recall, it is only 62 miles from the surface of the Earth to Space (accoding to the Fédération Aéronautique Internationale). So fuel consumption isn't a major 'biggie'.


I would love to see a shuttle launch, or hell, even a landing at Fairford.
Better get moving if I want to see one though!
 
Thorny
Posts: 1508
Joined: Thu Jul 07, 2005 8:44 am

RE: What Is The Deal With The Space Shuttle?

Fri Jan 18, 2008 12:23 am



Quoting Prebennorholm (Reply 34):

None of us living on planet Earth today will ever witness a manned Mars flight. It is too far away.

No it isn't. It is much farther away than the moon, but it is not a longer flight than cosmonauts already demonstrated on Mir.

Quoting Prebennorholm (Reply 34):
After almost 50 years of manned space flight we still get astronauts back in pretty bad shape from six months on the ISS.

No, we don't. Readaptation is always a little weird. Witness astronaut Stephanyshyn-Piper who fainted during the press conference last year shortly after landing. She'd only been in space 10 days. Other astronauts have pulled four and six month stints on ISS and walked around the Shuttle after landing. (NASA discourages but does not forbid this, they want to take blood and fluid samples and do other tests as soon after landing as possible before the body readapts to 1g.)

And the bulk of the zero-g issue can be eliminated with artifiical gravity, achieved by spinning the spacecraft on a long tether, probably with the spent booster rocket at the far end.

Quoting Prebennorholm (Reply 34):
Add to that the fact that landing and take-off from Mars demands a lot more energy than a similar Moon mission like Apollo.

That's just bigger fuel tanks. We'll almost certainly manufacture the propellant in-situ so that it doesn't have to be carried from Earth. The same engines used for landing can be used for liftoff. A derivative of the RL-10 burning methane instead of hydrogen seems most promising.

Quoting Prebennorholm (Reply 34):
And that with life support for a year long journey back home.

To be demonstrated on the International Space Station. The first parts of the U.S. closed-loop life support system are already in orbit (it will go fully-online with Node 3 in 2010.)

Quoting Prebennorholm (Reply 34):
Should manned interplanetary flight one day become practical because of some presently unknown technology breakthrough, then it will most certainly become "prohibited" to land on Mars.

No. Only nations which sign such a treaty would be "prohibited". Note that the United States never signed on to the Moon Treaty, either. I will guarantee you that the United States and China, at least, will never agree to that. Japan probably not, too.

Quoting Prebennorholm (Reply 34):
The reason is that it would be unavoidable to "pollute" Mars with micro organisms from Earth which could for ever spoil the value of future scientific work on Mars.

Then the damage is already done. Russia did not decontaminate Mars 2 lander before launch. It landed in 1971 and promptly died. But it did land. Also, there are meteorites from Mars on Earth and almost certainly some from Earth are on Mars. (It's harder to get from Earth to Mars because of Earth's higher gravity, but it is far from impossible.)

Quoting Prebennorholm (Reply 34):
And Mars is for certain the most valuable planet (next to Earth) in our solar system for exploring planetary developments and especially their climatic, environmental, and biological properties

And if the next generation of probes (Mars Science Laboratory, Exomars...) show unequivocably that there is no life today on Mars, as Viking has already strongly suggested...?

Quoting Prebennorholm (Reply 34):
For that reason a manned landing on an outer Jupiter moon will come before a manned Mars landing.

The radiation environment in the Jupiter system is far too dangerous for human exploration. Even the Galileo probe was badly fried by the time it finally ended its mission.

Quoting Prebennorholm (Reply 34):
I am also very sceptical about future manned flights to our own Moon. There isn't much more we can learn about the Moon from the surface. That's also the reason why all Moon missions during the last few decades have been Moon orbiters, not landers.

There is an enormous amount of surface exploration yet to be done. The Apollo flights only visited 16 sites in a narrow swath near the moon's equator and only on the near side. It is now widely regarded that the lunar poles are the most interesting places for research, and it is there that human exploration will re-commence at the end of the next decade.

Until the last few months, there had only been two missions to the moon since the 1970s. Both were orbiters (Clementine and Lunar Prospector) and one of them was a military mission using the moon as a convenient optical target. Japan and China recently launched lunar orbiters as their first lunar missions, so it is not unreasonable that neither mission was a lander. Lunar Prospector did a lunar impact at end of mission, as will LCROSS to be launched this year with NASA's Lunar Reconnaisance Orbiter. So there is in fact significant interest in the lunar surface.

Quoting Prebennorholm (Reply 34):
Maybe some future Moon missions will not be for investigating the Moon, but rather to utilize it. One interesting thing could be an astronomical radio telescope on the back side of the Moon. It's the only place in the neighborhood of Earth where we can work on radio astronomy without "pollution" from Earth. It might require manpower to build such a radio telescope on the Moon, but when operational it would certainly be remotely operated via Moon orbiting data relays.

Agreed, a far-side radio observatory is consistently one of the highest-interest projects for lunar utilization, and it will be man-tended, since people always nearby will contaminate the radio silence. The orbiting relays would contaminate the radio spectrum, so it is possible that a long cable would be strung around to a near-side transmitter, a'la transatlantic cables. The observatory will still have to contend with deep space missions transmitting signals back to Earth.
 
rwessel
Posts: 2448
Joined: Tue Jan 16, 2007 3:47 pm

RE: What Is The Deal With The Space Shuttle?

Fri Jan 18, 2008 2:43 am



Quoting Thorny (Reply 38):
The Apollo flights only visited 16 sites in a narrow swath near the moon's equator and only on the near side.

Obviously you meant 6, not 16.

Quoting Thorny (Reply 38):
Agreed, a far-side radio observatory is consistently one of the highest-interest projects for lunar utilization, and it will be man-tended, since people always nearby will contaminate the radio silence. The orbiting relays would contaminate the radio spectrum, so it is possible that a long cable would be strung around to a near-side transmitter, a'la transatlantic cables. The observatory will still have to contend with deep space missions transmitting signals back to Earth.

That's not really a big problem. Any relays just need to be designed to operate on astronomically uninteresting frequencies, and in very narrow bands (IOW, very little out-of-band noise). A narrow beam would help too.

Alternatively, you could go the optical route, and use a laser.

A bigger problem would be figuring out where to put the relay satellites, though. Perhaps at L4/5 and a really tall antenna tower.

OTOH, 5500km of optic fiber has a lot to recommend it. Its mass would probably be under 75kg/km, possibly under 50kg/km. And other than needing a (small) repeater station every 40-50km, would need little more than unrolling to put in place.

A series of towers is possible too. At 50m high, you'd need about 200 to go 5500km, but that doesn't look all that attractive compared to just unrolling 26km of cable (approximately the spacing between towers).

And you'd really only need about half that amount of fiber, since you'd put the dish pointing back to earth just far enough inside the near side to not have to worry about the libration. And you might not need to put the observatory in the exact center of the far side either.
 
Pope
Posts: 3995
Joined: Thu Mar 24, 2005 5:57 am

RE: What Is The Deal With The Space Shuttle?

Fri Jan 18, 2008 9:07 pm



Quoting Thorny (Reply 19):
No, it hasn't. Order of magnitude = multiply by 10. Apollo killed 3. Shuttle killed 14. Of course, Shuttle carries over twice as many astronauts per flight than did Apollo, and is closing in on an order of magnitude more flights to date. When compared to the number of flights and number of humans aboard those flights, Shuttle is only marginally more dangerous than Soyuz. Apollo's number of flights is so low that no statisically meaningful comparison can be made. (Although Apollo 13 came dangerously close to being fatal, and Apollo 6 would have aborted had a crew been onboard.)

Averaging over the length of the program, Space Shuttle costs about $500 million per launch. Titan IV was about $400 million each. Delta IV is around $250 million. But look at how much more versatile Shuttle is, with a crew of seven included in that cost. Saturn V was around $1 billion in 2004 dollars per launch. (Which is why LBJ and Nixon killed it in favor of something cheaper in the first place.) Shuttle didn't really increase costs over Apollo, but it failed to reduce them in any significant way.

You make several excellent points. I stand corrected.
Hypocrisy. It's the new black for liberals.
 
Thorny
Posts: 1508
Joined: Thu Jul 07, 2005 8:44 am

RE: What Is The Deal With The Space Shuttle?

Fri Jan 18, 2008 9:38 pm



Quoting Rwessel (Reply 39):
Obviously you meant 6, not 16.

D'oh! You're right.  embarrassed 
 
prebennorholm
Posts: 6418
Joined: Tue Mar 21, 2000 6:25 am

RE: What Is The Deal With The Space Shuttle?

Mon Jan 21, 2008 9:01 pm

I really enjoyed reading those long posts with optimism about manned Mars flights, especially by DfwRevolution and Thorny. I really do hope that you gentlemen one day will experience such a venture. I won't because I'm roughly at twice your average age.

But then I had the advantage to witness - as an (almost) adult man) the fantastic Apollo program from day one, the only extra terrestrial manned space to this very day. I remember hearing JFK on the radio same day as he announced the Apollo program.

I stumbled over a few things:

Quoting DfwRevolution (Reply 35):
I understand some of the skepticism because some study always has put Mars "twenty years in the future," as far back as the 80s.

You can call that "the 60s". If somebody in 1965 had insisted that in 1985 man had still not walked on Mars, then he would have been ignored as an idiot. The optimism and "can do" attitude was enormous in those days. And I believed in most of it.

When around 1970 the Shuttle began to take shape on the drawing board, then it was a 1977 EIS space tug to transport modules for among other things the Mars Ship into space. Six would be built (later reduced to five), and most of the time two shuttles would be working simultaneously in space. NASA talked "turn-around times" as if it was a DC-9 - two weeks, week-ends off duty, and it was ready to go again, year around. The buzzword was "five bucks per pound to space". 15 flights per shuttle per year for 15 years, they wouldn't need replacement until the larger, runway take off 1990 Shuttle successor.

By charging TV companies for launching geostationary satellites the Shuttle would balance at zero on the NASA financial sheet, or even make a profit! That was serious talk in those days.

One more thing: Nuclear power is mentioned as a new means of "really fast" space travel. I won't say it is impossible, but:

Nuclear power is good for producing heat. How do we convert heat into acceleration in space?

There is only one way to accelerate a mass in space. It is to "push" some other mass the other way. Today that other mass is burned rocket fuel, nothing else. The most efficient rocket engines (burning cryogenic, non-long time storable fuel) can reach an exhaust speed of roughly 10,000 feet/sec. That's an impressive number, but still it's only one third or half of low Earth orbit speed. So even if nuclear power could multiply the exhaust power by a factor ten, then still a very significant weight of "fuel" would be needed, well not real fuel, but some mass to push the other way.

If we imagine such an engine to perform a fast track to Mars, brake down to Mars orbit, land, take off, go fast back home, and brake again. We would probably still need 99% of the take-off mass to be exhaustible "fuel". It ain't easy. That's the reason why all long space flights in the solar system go in bent solar orbit and use gravitational pull from Jupiter, Venus and even Earth just to make it within years or sometimes decades.

Quoting Thorny (Reply 38):
Quoting Prebennorholm (Reply 34):
The reason is that it would be unavoidable to "pollute" Mars with micro organisms from Earth which could for ever spoil the value of future scientific work on Mars.

Then the damage is already done. Russia did not decontaminate Mars 2 lander before launch. It landed in 1971 and promptly died. But it did land. Also, there are meteorites from Mars on Earth and almost certainly some from Earth are on Mars. (It's harder to get from Earth to Mars because of Earth's higher gravity, but it is far from impossible.)

That 1971 "landing" was stupid. It was a result of a politically inspired "space race". It won't happen again. Hopefully it didn't do any damage.

The meteorite exchange between Earth and Mars is no problem. They got fried during entry into the atmosphere. We can hope that the Russian Mars 2 suffered the same faith.

But at the end of the day (or earlier) we should all study those fantastic space programs going on right now. It's not as spectacular on TV as Apollo, but going into the details I find it way more interesting than "a man walking on Mars".
Always keep your number of landings equal to your number of take-offs
 
Flighty
Posts: 7677
Joined: Thu Apr 05, 2007 3:07 am

RE: What Is The Deal With The Space Shuttle?

Mon Jan 21, 2008 10:10 pm

I think the triumph of NASA is really the Hubble Space Telescope. Nothing else really matches its contribution to science. What a great stroke of luck that was.
 
Thorny
Posts: 1508
Joined: Thu Jul 07, 2005 8:44 am

RE: What Is The Deal With The Space Shuttle?

Mon Jan 21, 2008 10:47 pm



Quoting Prebennorholm (Reply 42):
Nuclear power is good for producing heat. How do we convert heat into acceleration in space?

VASIMIR is one interesting concept...

http://spaceflight.nasa.gov/shuttle/...pport/researching/aspl/vasimr.html

Quoting Prebennorholm (Reply 42):
That 1971 "landing" was stupid. It was a result of a politically inspired "space race". It won't happen again. Hopefully it didn't do any damage.

We're not much better these days. Part of what makes the new generation of Mars missions so cheap (relative to Viking) is the shortcuts they've taken, and one of them is total decontamination of the spacecraft. On the budgets they have, it just isn't possible to totally eradicate any germs that might have gotten in. You need computer chips and systems that can survive much higher heat loads if you want to really bake out anything living, but chips that can handle that kind of enrivornment are a lot more expensive. And the higher quality clean rooms to build the spacecraft drive up costs a lot, too. They're taking more care with MSL, at a consequently higher cost.

Quoting Prebennorholm (Reply 42):
The meteorite exchange between Earth and Mars is no problem. They got fried during entry into the atmosphere.

That's far from a scientific concensus. Look up "transpermia".
 
TheSonntag
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RE: What Is The Deal With The Space Shuttle?

Mon Jan 21, 2008 11:20 pm



Quoting Flighty (Reply 43):
I think the triumph of NASA is really the Hubble Space Telescope. Nothing else really matches its contribution to science. What a great stroke of luck that was.

And it had to be repaired by humans in order to work properly...
 
prebennorholm
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 22, 2008 12:36 am



Quoting Thorny (Reply 44):
VASIMIR is one interesting concept...

Sure! Very interesting. But it does not offer a gigant leap in engine efficiency. Engine efficiency which could change a Mars return flight to a handful of months instead of years.

Also thanks a lot for your roundup about the Mars contamination risks. I read a lot about the Viking landers in the 70'es while they were going on. Somehow I assumed that the same precautions were taken today. We cannot fry modern computer chips, but anyway I would assume that they treat non-fryable modules with various "unhealthy" gasses and pack the landers in bioschields left to burn during entry into the Mars atmosphere.

There is always a risk involved. But that risk is really nothing compared to having sneezing men and women walking around.

Quoting TheSonntag (Reply 45):
And it had to be repaired by humans in order to work properly...

Not only to repair the Hubble, but also to modify and upgrade it with totally new sensors and instruments, and to re-fuel it to serve for decades. Those Hubble service visits are really some of the most spectacular achievements in space ever. That the spin-off from these visits is that we have widened our horizon in the universe in a breathtaking way, that's a fantastic bonus.
Always keep your number of landings equal to your number of take-offs
 
rwessel
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 22, 2008 5:29 am



Quoting Prebennorholm (Reply 46):
Quoting Thorny (Reply 44):
VASIMIR is one interesting concept...

Sure! Very interesting. But it does not offer a gigant leap in engine efficiency. Engine efficiency which could change a Mars return flight to a handful of months instead of years.

Two orders of magnitude increase in ISP isn't a giant leap?! What exactly are you hoping for?

Even using a nuke to run a large-ish collection of ion thrusters would increase ISP by an order of magnitude.

Of course in both cases you have to factor in the quite heavy nuke plant, but that just means you (ballpark) need at least as much reaction mass along as the mass of the reactor to break even. And sure, that implies a fairly large vehicle.

Just for grins, assume a couple of 100,000kg spacecraft. On one add 1,800,000kg of LOX and LH2 and 100,000kg of engines, and on the other add a 500,000kg reactor, 1,200,000kg of reaction mass and 200,000kg of ion engines. A total of 2000t in both cases. Let's ignore the issue of getting the silly things into orbit, and...

The conventional spacecraft will have a total delta-V of about 11.5km/s. The nuke/ion spacecraft will have a total delta-V of about 40km/s.

FWIW, the entire S6G reactor installation on a Los Angeles class attack boat is about 1,500,000kg, and puts out about 150MW. A significant part of that is shielding that you wouldn't need in space, nor would the reactor need to be anywhere near that big. So 500,000kg is very generous. If you halved the mass of the reactor, and added the equivalent amount of reaction mass, your delta-V goes to 64.5km/s.

Nor are the engine mass assumptions favorable to the nuke (they're excessively generous for the conventional vehicle as well, but it makes less difference there).

The reactor based design gives you a fair bit of growth room, whereas the low exhaust velocity of the LOX/LH2 engine will start to get really painful. Consider just adding 2,000,000kg of fuel or reaction mass to each of the proposed vehicles. The conventional spacecraft will have a total delta-V of 14.7km/s, while the nuke gets to 80.5km/s (heavy reactor version) or 99km/s (light reactor).
 
Flighty
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 22, 2008 5:26 pm

The final Hubble servicing mission (#4) is scheduled for August or September 2008.

6 new guidance gyroscopes, re-boost to higher orbit, new battery, and equipment upgrades. With luck, this will make Hubble last until 2013, at which time it will be retired. According to wikipedia.

Quoting Prebennorholm (Reply 46):
That the spin-off from these visits is that we have widened our horizon in the universe in a breathtaking way, that's a fantastic bonus.

I think in the future there won't be any doubt, the Hubble is probably the most important NASA activity since the moon landings. At least, the most successful. And the difficult repair missions are part of showing how it was truly a spaceflight challenge, not just astronomy alone.
 
Thorny
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RE: What Is The Deal With The Space Shuttle?

Tue Jan 22, 2008 6:56 pm



Quoting Flighty (Reply 48):
6 new guidance gyroscopes, re-boost to higher orbit, new battery, and equipment upgrades. With luck, this will make Hubble last until 2013, at which time it will be retired.

They will also attach a docking apparatus so that a future unmanned spacecraft can safely de-orbit Hubble. The apparatus could also be used by a visiting Orion spacecraft, so future repairs are not out of the question.

Quoting Flighty (Reply 48):
I think in the future there won't be any doubt, the Hubble is probably the most important NASA activity since the moon landings. At least, the most successful. And the difficult repair missions are part of showing how it was truly a spaceflight challenge, not just astronomy alone.

Voyager will be a close runner-up.

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