RIP Shuttle

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Dick Jacobson
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RIP Shuttle

Post by Dick Jacobson »

I was surprised to see the results of a recent SPACE.COM reader poll. 64 percent thought that we should continue operating the Space Shuttle beyond the currently planned last flight later this year.

Because of its design, the Shuttle cannot provide the capabilities that will be needed for further progress in human space exploration. Two of the most important capabilities are the ability to launch astronauts safely and economically, and the ability to launch heavy payloads (around 100 tons) for deep space vehicles and habitats.

Regarding safety, the risk of a fatal accident is now estimated at about 1/200 for a Shuttle flight. Although the astronauts are willing to accept that risk, the bigger problem is that the whole program is shut down for 2-3 years when an accident happens. With current technology, the only way to improve safety is with a launch escape rocket. Nobody has figured out a way to add a reliable launch escape system to the Shuttle Orbiter. The Ares I/Orion system expected to improve safety by a factor of 10. If it is replaced by a commercial rocket, this will also include a launch escape system. Since the Shuttle Orbiter is large and fragile, a collision with debris or meteoroids is almost as great a risk as mechanical failure. A small capsule is much safer both during launch and in orbit.

Economically, the Space Shuttle is a failure. Each launch costs about a billion dollars, most of which is from the enormous operating costs of the system. Under the new contract the Russians are charging $55 million per seat on Soyuz. SpaceX claims that they will be able to launch astronauts for $20 million a ticket (I hope they're right, I'll believe it when I see it.) At any rate, the best way we know of to lower costs is to get competitive private enterprise involved.

For large and heavy payloads, the Shuttle is limited to about 23 tons and a payload diameter of around 4 meters. Many modern rockets allow a 5-meter payload. The proposed Ares V would have a payload as large as 160 tons and 10 meters. For long space journeys and improved space stations we clearly cannot live within the limitations of the Shuttle.

A lot of people are concerned about the "gap" when we will be totally dependent on Soyuz. I'm not overly concerned about this. There is some technical and political risk but I think it is minimal. Soyuz is the most reliable rocket in the world; I think it has something like 100 consecutive successful launches. The Russians are our friends now (I think, I hope). They have a lot of money invested in the Space Station and we could make things very difficult for them if cooperation broke down.

Operating the Space Shuttle is soaking up $3 billion per year that could be better invested in new systems. With relatively small budgets, supersonic combustion ramjets (scramjets) are showing good progress and may eventually lead to a horizontal takeoff, horizontal landing system for launch to orbit. Most of the opposition to shutting down Shuttle is coming from congressmen from Florida and Alabama and Texas who want to ensure that the pork keeps flowing to their districts. The Shuttle was an amazing piece of engineering, but it doesn't meet today's needs and it's time to retire it.
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Chip
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Re: RIP Shuttle

Post by Chip »

You're persuasive here, Dick. Besides, a new century deserves a new technology and paradigm. In a way, it's a little like HST: sure hate to lose it but replacement(s) will make a quantum leap hopefully. "Hope and Change" values may be a little battered now for reasons largely unrelated, but we need to hold them nonetheless as general approach.

---Tom Lindquist
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"If I were wrong, then one would have been enough." Albert Einstein’s response to the 1931 pamphlet "100 authors against Einstein," by German Nazi Party as clumsy contradiction to Relativity Theory

"In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual". Galileo Galile

“Whoever undertakes to set himself up as a judge of Truth and Knowledge is shipwrecked by the laughter of the gods.” Albert Einstein
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Dick Jacobson
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Re: RIP Shuttle

Post by Dick Jacobson »

I think we are making a change away from the "Giant Leap" paradigm of human space travel (to use Neil Armstrong's words). The new paradigm is one of continual small improvements, the way most technology is developed. I think this change is long overdue.

First, we made a mad dash to the Moon. When that got boring, we decided to build a Space Shuttle that would reduce launch costs by 90% and make space travel almost as routine as airplane travel. That didn't work, so then we decided to build a giant Space Station where we would manufacture all kinds of wonderful products in microgravity. That's not working out, so then we decided to make a leap for Mars. The Augustine panel blew the whistle on that plan by pointing out that, giving funding trends, we'll never get there.

We don't need any Giant Leap government mega-programs right now. We need to figure out the best way to build space stations and the best way to get people into orbit. From there what's needed is gradual improvements in technology to increase our operating range in the Solar System.

The Soviet Union took the greatest leap of all when they proved that it's possible to put a man in orbit and bring him back alive. Now human space exploration can proceed without any more giant leaps until we decide to go to the stars.
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petemn2004
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Re: RIP Shuttle

Post by petemn2004 »

It is probably time to retire the shuttle as scheduled. It was truly unique vehicle the likes of which and capabilities that will not be duplicated for many years. It was over promised under performed yet has provided access to space for over 130 missions and has let us sharpen our skills and learn how to get along with other space fairing nations with the construction and operation of the ISS. The Hubble Space Telescope and the ISS are it's legacy.

The Constellation program was, and is, the correct architecture for the journey to beyond low earth orbit. $9 Billion has been spent on it already. It would cost $2.5 Billion just to shut it down with nothing to show for what we have already spent.


The new plan is a plan to no where. Over promises once again with vague goals. This plan was hatched by the Office of Management and Budget and did not involve the national space community (see Neil Armstrong's comments). The $6 Billion promised for the new plan will likely be siphoned off for other uses.

We should complete the Orion capsule and the Ares I rocket. At least it may live in time to reach the ISS and we should fund the Ares 5 as best we can.

The new plan now includes an Orion-lite capsule to be used as a life boat on the ISS but cannot be launched with humans on board. It is only used to get home in an emergency. There is no escape system. The astronauts are to be launched on a "commercial" capsule that cannot stay at the station for the required 6 months. A "commercial" capsule is not likely to be finished for over 10 years.


See the following:

Neil Armstrong testifying:
http://www.youtube.com/watch?v=0LYNaZc8XIQ


Gene Cernan testifying:
http://www.youtube.com/watch?v=RujHbPpnvj8&NR=1


If the Orion capsule and Ares I were to be continued we could hold our premier space fairing talent and organization together and maybe not see that it is only the Chinese who will be going back to the moon someday.


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Dick Jacobson
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Re: RIP Shuttle

Post by Dick Jacobson »

Mark, you raise some valid points about the cancellation of Constellation (along with Armstrong and Collins). I think their main points are that human spaceflight is dangerous and requires a great body of experience to reduce the risk, and that we need a specific destination to motivate us.

NASA is currently struggling to develop human-rating standards for rockets developed by other organizations. I think they should demand a certain minimum number of consecutive successful flights before a rocket qualifies for human launch. I see no reason why a private contractor should not be able to achieve an acceptable level of safety.

As for destinations, the Augustine report emphasized the need to concentrate on capabilities, not specific destinations. I think it is premature to decide right now on a specific destination for the first flight beyond Earth orbit. In the next few years we should gather a lot more information to inform this decision. The discovery of water on the Moon has made it much more interesting, but should we build a large and very expensive permanent base at the lunar south pole, or send a series of missions to various locations? In the near future we should be able to determine which specific asteroid poses the greatest threat to Earth (maybe it will be Apophis), and that may make it a high-value destination. I think Mars orbit is a great intermediate step before a Mars landing, since the astronauts could operate rovers all over the surface and explore Phobos and Deimos. Right now what we need to do is develop a heavy launcher, better in-space propulsion, and long-term life support systems.

I think what killed Constellation is the high costs and low return. It seems to me that they haven't accomplished that much for the $9 billion spent. They have done one launch of Ares I-X, a slightly modified Shuttle SRB with a dummy second stage. Meantime, while spending less than 1/20 as much ($400 million), SpaceX has put a payload into orbit on the first try with their Falcon 9. Granted, they have had some failures with the smaller Falcon 1, and the Falcon 9 has only about half the capacity of Ares I. Constellation has done one test of the launch escape system using a boilerplate Orion capsule. The estimated launch cost for Ares I is $900 million, about the same as Shuttle. It may be a reasonable system for deep-space missions, but would be terribly inefficient for supporting ISS.

By the way, the SpaceX web site says that the Dragon capsule will be able to stay in space for a year or more.

Personally, I would like to see us continue both programs, Constellation for deep space and a private contractor system to support the Space Station. But with the anti-tax sentiment prevalent today, we can't support both Constellation and ISS and I'm not sure we can continue to support human space exploration at all.

As I'm sure you're aware, many of the current and former astronauts including Buzz Aldrin strongly support the new plan. The experts disagree, I'm not an expert, and I don't know who is right. The Obama plan is based on the Augustine report, which was developed in consultation with many spaceflight experts. Naturally, many people were not consulted and there are a lot of sour grapes.
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Dick Jacobson
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Re: RIP Shuttle

Post by Dick Jacobson »

I just read where SpaceX is now estimating that it will cost $1 billion to develop a launch escape system for their Dragon crew module, up from a previous estimate of $350 million. This makes me doubt their low-ball estimates of the cost of crew transport. No simple answers...
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Brad E
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Re: RIP Shuttle

Post by Brad E »

at the end of the day, Launch esape systems (LES) are really just a PR move rather than a safety one. For example, a former colleague of mine (older gentleman) who had experience working on the UNIVAC / COLOSSUS computer mainframes that sent the Apollo capsules into orbit and beyond, told me that if you just did the math, by the time the computers are able to realize something ohrrible is about to happen, and then fire off all the sequences and activate all the proper things, and then finally fire the LES... in the event of a catastrophic failure a la "Challenger" or something similar involving an explosion of the propellant tanks the LES would NOT be able to get the capsule / crew out of harms way fast enough without risking serious damage to the capsule, and or loss of the crew..

that said, I'm all for the ability to abort the launch and float down on a parachute, but all that's needed IMHO is a system to break the Capsule free of the main body of the craft, and activate the chutes as needed. anything more.. like they are trying to do now by bolting a huge solid booster on the nose of the craft in the attempt to pull it out of the even horizon of an explosion.. is a waste. or at best a farce..and if it busts a billion to develop.. you know it's just a PR / black hole money pit at that point to satisfy the bureaucrats that want to effectively wash their hands in the event of another spacecraft disaster simply to cover their own butts politically.


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Dick Jacobson
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Re: RIP Shuttle

Post by Dick Jacobson »

I'm not a rocket expert, but all of the experts (except for the one you quote) seem to agree that a launch escape system is a vital safety feature and the only way to achieve "reasonable" safety levels (i.e. 99.9% or better) given today's unreliable rockets. I don't think any launch escape system has ever been used in a real-life abort and we won't really know if they work until that happens. The Orion LES has been tested once, and achieved 16 G's of acceleration which the designers feel will be enough to escape an exploding rocket. Some of the capsule designers are now talking about a "pusher" LES which could also be used to de-orbit the craft. One of the steps in "human-rating" a rocket is to install a system to monitor its performance and instantly trigger the escape system if something goes wrong. Whether that could have saved the Challenger astronauts is probably a question that can never be answered.

As for SpaceX's $1 billion estimate for a LES, this makes no sense to me if they could develop the Falcon 9 and launch it into orbit for $400 million. SpaceX CEO Elon Musk seems to be an expert at getting government subsidies for his projects (Tesla is another one) and maybe he sees an opportunity for a big fat taxpayer bailout.
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Re: RIP Shuttle

Post by Brad E »

Just to be clear.. I didn't mean that an LES isn't needed.. because it IS.. I'm just skeptical of a $1 billion price-tag for a solid rocket bolted to the top of a capsule, with 4-valves to direct the thrust.. it's not that hard to work the math in building a solid booster.. and to figure out it's thrust & take that and work out theoretical G-loads.. The inherent danger fiscally, is when we let NON-aerospace people into the mix to make decisions on whether or not to buy this stuff. a lawyer.. elected to an office, that uses technology only in a cell-phone/laptop capacity.. with no aerospace background should not be making $1 Billion dollar decisions on something that may or may not work as advertised.
An account from Leaving Earth by Robert Zimmerman:

It was not to be. Ninety seconds before blast-off, with Titov and Strekalov waiting at the top of their fully-fueled Soyuz rocket, a fuel valve at the base of the rocket malfunctioned, opening and spilling fuel uncontrollably onto the launchpad. A fire broke out and flames engulfed the rocket with its 180 tons of very flammable fuel. At that moment, the automatic launch-escape system should had kicked in, executing the following steps: First, explosive bolts fire, flinging the Soyuz T capsule free of the three-stage rocket. One second later, solid-fuel engines in a tower attached to the top of the capsule ignite, lifting the Soyuz T orbital module and descent module away and clear. Five seconds after that, more explosive bolts fire to separate the manned descent module from everything else. Its parachutes then release and its retro-rockets fire, slowing the capsule enough for a safe landing.

The automatic launch-escape system did not kick in, however. The fire had burned the system’s wiring, preventing it from being activated automatically. Feeling strange vibrations and seeing black smoke and yellow flames outside their window, Titov and Strekalov tried to fire the launch-escape system manually, only to get no response. To fire the escape system manually from mission control required each of two different operators, located in two separate rooms, to press separate buttons at the same time. With flames rising from the launchpad and the entire rocket already leaning 20 degrees to the side, controllers scrambled madly to get the system to free.

Just 10 seconds after the flames first appeared, controllers miraculously managed to somehow do this, activating the escape system and throwing Titov, Strekalov and the Soyuz T capsule more than 3000 feet into the air. For five seconds the emergency engines fired, subjecting the two men to forces exceeding 15 g’s. Then the engines cut off, the descent module separated, and its parachutes unfolded.

At that moment, the entire rocket and launchpad exploded. The blast was so intense that the capsule, three miles away, was thrown sideways, and launchpad workers in underground bunkers felt the pressure wave.
so.. by this account.. at a 3-mile distance the capsule was literally thrown to it's side by the shock wave.. so I guess I need to be convinced that a LES could get a crew & capsule out of the way of that kind of violent event fast enough to not: a) damage the capsule or b) kill the crew trying to do so.

if one watches the replay of the Challenger accident.. (Tragic.. but a fact of history..R.I.P astronauts) the failure of the O-ring on the booster can be seen gradually starting then getting worse over several seconds, but when the booster is compromised and the main tank goes.. it's over.. 16G's of acceleration or not.. NO LES would get them out of something THAT big.. that fast.. so my opinion.. is why bother with an expensive LES like Orion's / Apollo's. if it's possible why couldn't the capsule (if it's thrusters had the power) auto-orient itself and then fire the chutes as an abort procedure shortly after launch.. or in the case of the Dragon Capsule from Space-X have thrusters on board capable of de-orbiting the craft.
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FF2Rydia
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Re: RIP Shuttle

Post by FF2Rydia »

About the LES and Challenger: Remember that the crew compartment did survive intact until water impact, even climbing an extra 20,000 feet on the ballistic path it was on at the point thrust was lost. The key for crew survival (other than parachutes, that is) in Challenger was power, pressure, and oxygen, and it is believed that none of those were present. However, Challenger was a rather unique failure, given where everything was located, so I'm not sure anything can be inferred from it in terms of survivability in other launch systems.

Although, with regard to the computer speed question, in Challenger, the computers did detect the loss of fuel and shut down the SMEs.
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Dick Jacobson
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Re: RIP Shuttle

Post by Dick Jacobson »

The commander of Challenger said "Uh-oh" just before the thing blew up, so I would think that there would have been enough time for a LES to fire and blast them to safety. Undoubtedly any abort is a high-risk situation but if the system works 90% of the time it might increase the interval between fatalities from 10 years to 100 years, certainly an important factor and probably something the taxpayers or customers would demand.

I just read in Aviation Week that three companies that are developing manned capsules privately - Boeing, Dream Chaser, and Blue Origin - are all incorporating "pusher" type LES that would go into orbit and their propellant could be used for maneuvering.
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