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« Vision In The Balance | Main | Let My People Go »

Nonsense From Easterbrook

You know, correcting Gregg Easterbrook's malanalysis of space issues could be a full-time job in itself. It's dismaying that people who should be intelligent enough to otherwise know better glom onto them in order to validate their own unknowledgable preconceptions on the subject. And by the way, it's no insult to be called unknowledgable on these issues. Few people are, even many in the space industry. To become so requires a huge investment in time and study that few have the time for.

I find it particularly frustrating, because there is so much to legitimately criticize in the recent proposal, NASA, and space policy in general, but the opportunities to do so are drowned out by better known, but far less knowledgable people who rest on their laurels from a few lucky shots against the shuttle a quarter of a century ago.

I don't really have time, but since he gets entirely too much credibility in the blogosphere and elsewhere, I'll take apart his latest bit of misinformation.

Just the cost numbers for the Crew Exploration Vehicle alone--forget all the probes, colonies, and other stuff--make Bush's announcement yesterday an all-time monument to budgetary low-balling. He declared that for the next five years, $12 billion will be devoted to the Moon-Mars initiative. That, the president said, is enough to fund new the Moon probes and development of the ill-named Crew Exploration Vehicle. This figure is utterly ridiculous, a mere fraction of what will be entailed in anything beyond some "paper spacecraft"--engineers' lingo for studies and Power Point presentations of hardware that never gets built. Boeing expects to spend around $7.5 billion merely to develop the new 7E7 jetliner, which will stay within the atmosphere and use very well-understood engineering. The development cost of the Crew Exploration Vehicle will be several times greater

This paragraph is chock full of nonsense. He's doing something worse than comparing apples to oranges--he's comparing space capsules to commercial airliners. There is no way to infer the costs of one from the other--they are totally irrelevant to each other. One carries hundreds of people, has to fly thousands of times, provides its own propulsion, has to meet all requirements of FAA certification. The other is simply a can that carries four people or so, with basic subsystems like a reaction-control system, avionics, life support, with thermal protection and a recovery system if it's going to do an entry. And in fact, it's also "well-understood engineering," and has been since 1968 or so. It may be expensive, but there's no way to tell by looking at airliners.

The best way to tell is to do a parametric cost analysis on it. It's basically an upgraded Apollo capsule (and perhaps service module for modest propulsion and additional consumables). We know how much that cost the first time, and it should be easier now, particularly considering the technology advances over the past four decades (e.g., computer microization). If NASA can't develop that vehicle in a few years for a few billion, it should be disbanded.

The timetable is also a low-ball. Bush declared that the Crew Exploration Vehicle would be tested in 2008, just four years from now. There's no way on Earth, as it were, this could happen without a cost-no-object crash program to rival Apollo. The Air Force's new F22 fighter has been in development for 13 years; an entire new spaceship can be developed in four years?

I didn't hear Bush say that. 2008 was the first robotic probes of the moon in anticipation of a manned return seven years later.

If we could develop such a thing in four years the first time on an Apollo budget, why couldn't we affordably do it again in ten years (first flight is supposed to be 2014) on a less urgent basis?

[Update]

Commenter Duncan Young says that Gregg is right on this point, but that doesn't make him right that it can't be done. As I said, it's perfectly feasible to develop and test a capsule, and associated service module, in four years, particularly since we already know how to do it, and have done it before. Apollo was a crash program, but the capsule itself wasn't really a long pole. As an aside, this is probably the only major development that will have to occur during Bush's term of office.

[/Update]

It may be that we can't, but Gregg certainly offers no coherent reasons why we can't, except with another absurd comparison--to a multi-mission fighter that's gotten into a lot of political problems with interservice rivalries, and which again, fly hundreds of sorties and have to be maintainable by high-school grads.

And I don't know what Gregg means by "spaceship," unless it's a way of intimidating his readership into thinking that he's one of them there "rocket scientists," and knows what he's talking about. If he means a "ship" that flies in space, there's nothing inherently expensive or difficult about that.

It's just a capsule. It's not a launcher.

But if, as Bush declared, it will be capable both of flying back and forth to the space station and of flying to the Moon, we're talking quite a machine.

You mean, like the Apollo capsule, which was capable of both flying back and forth to the moon, and to Skylab (and to meet a Soyuz)?

Quite a machine. How ever will we do it?

Alternatively, a smarter approach might be to construct one spaceship that always stays in space, looping back and forth between Earth and Moon; people, supplies, and fuel would be launched to meet the ship in Earth-orbit, but the ship itself would never come down. (This was a Werner von Braun idea.) That would mean design, engineering, and construction of a type of flying machine that has never existed before. Development of the space shuttle cost between $50 billion and $100 billion in current dollars, depending on whose estimate you believe. The idea that something more challenging, the first-ever true spaceship, can be developed for $12 billion is bunkum.

I hesitate to call ideas loopy, but this one is literally. He says that it would be smarter, then he says it would "mean design, engineering, and construction of a type of flying machine that has never existed before." He's criticizing a plan that doesn't require that as being unaffordable and requiring decades, and then proposing one that's undefined and has never been done before as somehow "smarter." On what planet?

Again, this is not a Shuttle. This is not an airliner. It's not a fighter jet.

It's a supersized Apollo capsule. We have an existence proof that we know how to build them. It will be easier now than it was forty years ago, honest. If we need a separate lander to get down to the lunar surface, we know how to build those, too. It's even possible to develop things in parallel, though I suspect that only the capsule will be required for the 2008 date, so they have something to replace the Shuttle capability for crew transfer in 2010.

And what's going to put this Crew Exploration Vehicle into orbit? No rocket that exists in the world today is capable of lifting the Apollo capsule and Moon lander of the late 1960s. Unless the Moon-bound twenty-first-century Crew Exploration Vehicle is going to be significantly smaller than the Apollo of a generation ago--carrying just one person and no supplies--a new, very large rocket will be required.

No, Gregg, we have acquired no experience with docking vehicles, or orbital mating over the past four decades. It's inconceivable that we could launch a capsule on one flight of a Delta or Atlas, and a service module on another flight, and hook them up in LEO. We have to redevelop Saturn.

And of course, even if one is truly unknowledgable enough to believe that, we could develop a Shuttle-derived launch vehicle with Saturn-like capability in about four years for a billion or three (though that's a separate budget than the one for the Crew Exploration Vehicle). We've known how to do that since the eighties. We haven't done it because there's been no need, not because it can't be done, or because it's unaffordable.

We shouldn't expect George W. Bush himself to know that $12 billion is not enough to develop a spaceship. We should expect the people around Bush, and at the top of NASA, to know this. And apparently they are either astonishingly ill-informed and na´ve, or are handing out phony numbers for political purposes, to get the foot in the door for far larger sums later.

And we should expect a pontificating journalist, masquerading as a space expert, to know that a Crew Exploration Vehicle is not a "spaceship" in the sense that it will go from earth to moon unaided, and that he wouldn't throw out phony numbers and strawman arguments for...well, I can't figure out what his purposes are, other than to see himself write.

Posted by Rand Simberg at January 16, 2004 08:21 AM
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Easterbrook already on Mars, Sullivan likes the view
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Comments

I develop add-ons for the realistic space sim Orbiter http://www.orbitersim.com (working on Mercury at the moment). What I am wondering is that whether they are going to build this capsule totally brand new. Or are some existing projects they can use to develop from. For example I think in the early nineties the european were testing a re-entry vessel that was a scale copy of the apollo capsule. Of course there the soyuz and the TKS that the russian built for their lunar programs but adapted for making space station modules. (I believe Zarya is a TKS devired module).

I am curious mainly there is a bunch of us who want to make a model on what the CEV could be. Certainly all we have are capsule design that NASA shows as part of the OSP project, and the one Boeing graphics that has a orbital module like Soyuz/Shenzhou.

I also wonder they would use for the main propulsion engine?

I think the real killer for the CEV is decide how far to push the durability. All manned spacecraft to date rely on supplies from earth to remain operating. For a Mars mission we are going to need to built crafts that are capable of long-duration operation without re-supply.

They should go the incremental route in my opinion. But if they try to make too giant of a leap then we could wind up with another venture star.

Rob Conley


Rob Conley

Posted by Robert Conley at January 16, 2004 09:56 AM

The CEV almost certainly won't be used for Mars missions, or if it is, it will be a small component of the total injected system.

Posted by Rand Simberg at January 16, 2004 10:00 AM

Unfortunately, well-known bloggers like Andrew Sullivan have siezed upon Gregg's analysis and used it to justify their fervent opposition to the Bush space initiative. Rand, you and others need to give his column the thorough Fisking it deserves and let Andrew know directly. He snidely dismisses emails from unknown space buffs like myself, trumping our points with "Eastebrook says differently".

-p (already emailed the site)

Posted by philw at January 16, 2004 10:04 AM

The New Zealand Herald was also spewing nonsense about Bush's space plan today: Bush Space Plan a Setback for Peace
http://www.nzherald.co.nz/storydisplay.cfm?storyID=3544048

I give it my best frisk..
http://stellarlink.com/blog/archives/000035.html

Posted by John Kavanagh at January 16, 2004 10:12 AM

I think that requiring NASA to come up with an Apollo Mark 2 in less time and for less money (inflation adjusted, of course) than the original should be considered a reasonable goal. That some people that that's unreasonable says a lot about what has happened in the last three decades.

The problem with Easterbrook, typified by his assumption that return to the moon must be done by a single launch LER mission, seems to be that he can't conceive of any other way to do this other than to repeat Apollo exactly. Unfortunately, I suspect a lot of NASA has the same attitute.

(I've always thought we need the Clarke type space station, which functions as a transfer point between LEO mission and other destinations like geosynchronous, the moon and asteroids. Unfortunately, there's no way to convert the existing one to that "mission". )

Posted by Raoul Ortega at January 16, 2004 10:15 AM

Is there a specificif term for bloggers with no trackback ( and to a lesser extent, public comments ) system ? Its like speaking in an auditorium while wearing earplugs.

Posted by kert at January 16, 2004 10:30 AM

I question that a Apollo Mk II is the best way to go. We had proposals in the past for the Big Gemini. We should look at the service module-capsule-orbital module setup of the Soyuz.

It seems to me we should use whatever we have the most data for so we are not starting at ground zero.

Posted by Robert Conley at January 16, 2004 10:57 AM

Another Easterbrook brain f*rt:

"Gravity declines with distance, meaning the closer you get to something, the more intently it tugs on you. (This is one reason why astronauts in orbit aren't truly weightless, rather in "microgravity"--two hundred miles from the surface of the Earth, the tug on them has declined.) Dark energy appears the opposite of gravity, gaining strength with distance. That is to say, the farther away something gets, the more intently dark energy pushes."

Originally, it was:
"This is why astronauts in orbit aren't truly weightless, rather in "microgravity"--two hundred miles from the surface of the Earth, the tug on them has become slight."
:prior to email bombardment

This is basic stuff - he really should stick to writing about cheerleaders.

Posted by Duncan Young at January 16, 2004 11:10 AM

Rand writes:

>> And of course, even if one is truly unknowledgable enough to believe that, we could develop a Shuttle-derived launch vehicle with Saturn-like capability in about four years for a billion or three (though that's a separate budget than the one for the Crew Exploration Vehicle). We've known how to do that since the eighties. We haven't done it because there's been no need, not because it can't be done, or because it's unaffordable.

Yeah!

Won't a lunar base need supplies to be built? How many Atlas/Delta launches would be needed to move the needed mass? Isn't a shuttle derived booster the obvious complement to the CEV?

Posted by EldonSmith at January 16, 2004 11:18 AM

No, a Shuttle-derived booster implies keeping the Shuttle infrastructure around indefinitely, which would be very expensive. If we are serious about supplying a government lunar base, we'd simply put out a request for bids for delivery of supplies to orbit (or even to the moon), and let the private sector figure out the best way to do it.

They could probably just piggy back on the supply ships of filet mignon, caviar and foie gras to the lunar resorts. ;-)

Posted by Rand Simberg at January 16, 2004 11:32 AM

Rand,

"I didn't hear Bush say that. 2008 was the first robotic probes of the moon in anticipation of a manned return seven years later."

Easterbrook did get one thing right.

From the President's speech:

Our second goal is to develop and test a new spacecraft, the crew exploration vehicle, by 2008, and to conduct the first manned mission no later than 2014.

Posted by Duncan Young at January 16, 2004 11:46 AM

I'm not sure how much need we have for a Saturn V-type lifter. Sure, if you want to send up everything in a single shot, you'd need the massive lifting capability of the Saturn V. But launching two or even three Delta 4's or Atlas V's would be more cost-effective, and we have those in the inventory *now*. Man-rating the Delta 4 Heavy could probably be done in a couple of years.

Using an expendable rocket is cost effective, but it's also a crew-safety issue -- the capsule-style CEV is inherently safer than the Shuttle because it sits *on top* of the rocket rather than on the side, allowing the capsule to eject if things go badly. You put the crew as far as possible from the engines.

Posted by Monty at January 16, 2004 11:54 AM

Its talk like Easterbrook's that perpetuates that notion that space travel has to be expensive. Its like going into a Car dealership and declaring to the salesperson, "There's no way you are gonna be able to sell me this Dodge Neon for less than $140,000."

Plus I believe Von Braun advocated a earth orbiting station to sling shot landers to the Moon and beyond, not a transfer station concept.

He needs to read the latest space.com article about how excited the Russians are about the proposal. They sound as if they are willing to leave China in the lurch and jump onto the American bandwagon.

http://space.com/news/russia_bush_040115.html

He especially needs to read the part: "Another space designer, Leonid Gorshkov of the RKK Energiya company that builds Soyuz and Progress spacecraft, says it has designed a spacecraft which can carry a crew to Mars as early as 2014 for US$15 billion.

Gorshkov told ITAR-Tass that the 70-metric ton (77-ton) spacecraft modelled on the Russian Zvezda module for the ISS could be assembled in orbit from components delivered by Proton booster rockets."

We could test the concept by strapping some rockets onto the ISS and shooting it off into space unmanned to see how well it survives. j/k

Posted by Hefty at January 16, 2004 12:08 PM

My CEV speculation. Feel free to use it.

Posted by bchan at January 16, 2004 12:17 PM

A couple of comments on bchan's CEV (for lack of a better place) - there is no provision for non-terminal areobraking, and I dont think you want cryogenics for extended space operations. Interesting first try, though. I think there might be something to be said for a biconic re-entry module, instead of the Apollo gumdrop - but that is just me.

And on Rand's update - just to make clear, I think four years is possible for CEV first flight, but they need to start making hard choices *very* soon - which may be hard to do in an election year.

Posted by Duncan Young at January 16, 2004 12:36 PM

NASA should take bids for who can resupply the station (and possibly provide lift for the moon missions). If someone can do it cheaper with their own equipment (or by using the existing shuttle fleet) they should get the contract.

That way NASA gets out of the cargo hauling business. Its possible nobody could do it cheaper than NASA but I doubt it.

Posted by ruprecht at January 16, 2004 02:23 PM

They are thinking about exactly that.

QUESTION: With the crew exploration vehicle, what's the line of thinking on how to do cargo? Is Shuttle-C or concepts like it back on the table? Or is that still fluid as well?
O'KEEFE: Yes, that's a dimension of what we're going to have to lay out here, of how you provide cargo capabilities. And there are those kinds of options on the table: Do you use, you know, a range of different assets for those purposes, or do you look at developing very specifically through commercial, entrepreneurial means, whatever, a variety of different cargo lift capabilities that have been discussed, advertised and talked about there. I think this is going to put a premium on innovation, creativity, different ways of looking at challenges and different ways of accomplishing those objectives.

Posted by Duncan Young at January 16, 2004 02:34 PM

But on-board the ISS, commercial activities are meeting resistance:

John Marburger, the president's science adviser, both supported the idea of a revamped space policy. He told NASA's chief, Sean O'Keefe, and the president repeatedly the purpose of the International Space Station should be for human research only, not for commercial projects.

http://www.spaceref.com/news/viewnews.html?id=916

Posted by John Kavanagh at January 16, 2004 03:04 PM

That's all right--the ISS (or any NASA facility) isn't particularly useful for commercial projects.

As soon as we have affordable launch, we'll have affordable stations, designed to purpose.

Posted by Rand Simberg at January 16, 2004 03:12 PM

Easterbrook's piece is so obviously wrong that it is easy to dismiss it as either a complete fiction or a deliberate concoction of lies.

In either case, it illustrates the need for the pro-space community to put aside our differences about funding and method, and to focus some attention to the obvious need to convince the American electorate that human space travel is necessary. While we quibble about public or private sector funding, or play Monday morning quarterback re: spacecraft design, we forget that the value and need of human space travel is far from widely accepted.

We need to make sure the debate about human space travel is resolved correctly. Unless that happens, fables like Easterbrook's will continue to sway the opinions of folks who know no better.

Posted by billg at January 16, 2004 03:57 PM

Excuse me??

Wasn't Von Brauns origina Moon misssion proposal Earth orbit Rendevouz via Saturn IB's?

Remember too, we can use high ISP solar elecrtic propulsion to push non-time critical cargos/ landers / habs to lunar orbit.

Have we also not discovered some low energy orbit transfer techniques since the 70's?

I have also heard rumors of a 40 ton variant, a Delta 4 super heavy, from a friend who works at Boeing. Said something about 4 strap on core boosters and a stretched upper stage. Don't know if he was blowing smoke or serious.

Posted by Mike Puckett at January 16, 2004 04:11 PM

bchan's CEV modules are very interesting. What size booster would be needed to lift the largest of those modules?

Posted by EldonSmith at January 16, 2004 05:08 PM

To my mind the heaviest of the modules would be the Nuclear Module (NM). As I conceive it, this vehicle would be something along the lines of the Nerva 2/NTR upper stage proposed back in 1991: empty mass: 27 mT, vacuum thrust 4,000 kgf, Isp 925 sec, burn time 3,575 seconds. (The Nerva 2 design had a diameter of 10 meters and a length of 47.6m, but I fudged this in order to keep the NM's diameter equal to that of the rest of the CEV stack.) Full up this stage would mass 158.4 mT -- two launches of the Shuttle-C would do it, one carrying the dry vehicle, one carrying reaction mass (LH2). We'd only need two or three -- one for the Luna run, one for geosynch/lgrange duty,and one docked at the assembly base for rescues. We could launch another three later for the Mars Expedition to use.

The next heavest module, the Landing Module (LM) I figure to be about the size of a Russian 77KM module (i.e. Zarya ISS). Strip off the UISS equipment, add landing gear, engines, and so forth, and call its mass about 20,000 mT, putting it within the lift capability of the three-stage Proton 8K82M.

The Mission Module (MM) is supposed to be built more or less along the lines of the American ISS module Destiny -- that would make it 8.4 meters long and 4.2 meters in diameter with a mass of 5 tons metric. Add two tons for equipment and consumables just to be safe - call it 7 tons metric, roughly the mass of a Soyuz TM, and launchabe on any number of LVs.

As for the DM/CM/RM/SM core module stack, I'd guess it to come to more or less the same weight as the Apollo-Soyuz version of the Apollo CSM -- 15 mT or so -- and could be launched by the Proton or similar vehices.

I'm obviously no engineer, so all of this is probably completely wrong. (All figures are from Mark Wade's site.)

Posted by bchan at January 16, 2004 06:33 PM

What modules would you propose if limited to 30 or 40 tons (more or less) as with a steroid enhanced Delta IV heavy - or super heavy?

The question I have is whether we need to keep shuttle derived boosters (B/C or Ares) as an option or whether the Bush vision can be achieved after scrapping all shuttle infrastructure.

Posted by EldonSmith at January 16, 2004 07:35 PM

nuclear booster option

Imagine a nuclear upper stage for the Delta IV heavy booster. I'm no rocket scientist, but wouldn't that alone boost the payload to orbit from the original 20 tons, to more like 50 tons? Just two of those nuclear Delta IV's would equal the payload of a Saturn V.

Better yet, design that nuclear upper stage for reusibility and leave it parked in LEO, and that gives you near term an orbital transfer propulsion module for CEV missions to the moon and nearby asteroids.

Posted by Brad at January 17, 2004 10:19 AM

I'm surprised I haven't seen it said yet, considering whose blog this is - orbital assembly of CEV and its propulsion modules means higher launch rate. Higher launch rates will drive down costs. That alone is sufficient reason to support the CEV concept.

This plan is as good as we could possibly have hoped for. The idiots of the Apollo Cargo Cult will eventually calm down, and we'll see real progress.

Incidentally, Jeff Greason posted an excellent analysis of what CEV will probably look like on sci.space.policy

Posted by Andrew Case at January 17, 2004 10:28 AM

I would love to see a nuke upper but remember, cargo and non-time critical supplies (basically anything but astronauts) could be delivered ba a solar powered high isp transfer vehicle that could push much cargo for little propellant.

Also, I ask you guys. Hasnt there been some breakthru in the past decade or so regarding highly efficient low energy transfer orbits to the moon that could further enhance efficiency?

Posted by Mike Puckett at January 17, 2004 10:50 AM

No one is going to use a nuclear upper stage on a launcher. Nukes will be used in space, but they will be launched in an inert state, and only powered up after they're in a sufficiently high and stable orbit.

Posted by Rand Simberg at January 17, 2004 08:16 PM

Easterbrook's opposition is rooted in his identity as journalist and leftist. Actually knowing something about engineering would handicap his writing, as he could no long as easily adapt his logic to lead to his emotionally pre-determined conclusions.

There is no point to logical argument directed at Mr. Easterbrook. He does not arrive at his positions by logic.

Instead, I think the point to hammer home to the general community of listeners is: a journalist's opinion on engineering should be given as much weight as the opinion on medicine of an actor who plays a doctor on TV. It *is* rocket science, and the standard liberal-arts education a journalist gets in no way prepares him to even understand engineering issues.

Posted by Stephen Maturin at January 17, 2004 08:44 PM

Duncan Young at January 16, 2004 11:10 AM

>Another Easterbrook brain f*rt:

>"Gravity declines with distance, meaning the closer you get to something, the more intently it tugs on you. (This is one reason why astronauts in orbit aren't truly weightless, rather in "microgravity"--two hundred miles from the surface of the Earth, the tug on them has declined.)

He actually wrote something like that? I'm appalled, I truly am. Apparently the man knows little or nothing of physics. The force of earth's gravity 200 miles up is less than on the earth's surface, but not substantially so.

Of course the reason that astronauts experience weightlessness while in a 200 mile high orbit has nothing to do with the fact that they are 200 miles up. Apparently he is unfamiliar with the term "free fall."

Posted by raj at January 18, 2004 04:16 AM

Duncan Young at January 16, 2004 11:10 AM

>Another Easterbrook brain f*rt:

>"Gravity declines with distance, meaning the closer you get to something, the more intently it tugs on you. (This is one reason why astronauts in orbit aren't truly weightless, rather in "microgravity"--two hundred miles from the surface of the Earth, the tug on them has declined.)

He actually wrote something like that? I'm appalled, I truly am. Apparently the man knows little or nothing of physics. The force of earth's gravity 200 miles up is less than on the earth's surface, but not substantially so.

Of course the reason that astronauts experience weightlessness while in a 200 mile high orbit has nothing to do with the fact that they are 200 miles up. Apparently he is unfamiliar with the term "free fall."

Posted by raj at January 18, 2004 04:16 AM


Rand Simberg at January 17, 2004 08:16 PM

>No one is going to use a nuclear upper stage on a launcher

This is true.

My father was involved in a project at GE (Evendale, OH) in the 1950s to develop a nuclear-powered engine for aircraft. According to him, they developed a very good workable engine, but the problem was that they could never figure out how to protect against release of significant amounts of radiation in the event of a crash. The same problem would obviously adhere to a launch vehicle in the event of a crash. Hence, they will not be used.

Posted by raj at January 18, 2004 04:18 AM


Stephen Maturin at January 17, 2004 08:44 PM

>Easterbrook's opposition is rooted in his identity as journalist and leftist.

I hate to tell you, but the fact--that you may want to consider--is that "leftist" is a noise word. As well as a turn-off word: it is clear that, among some sub-set of people, "leftist" is used as a pejorative merely to refer to anyone they disagree with. I'm sure that more than a few people stop reading posts or comments when they encounter the word. (Unless one is reading on FreeRepublic.com, of course.)

If you have substantive arguments regarding Easterbrook's positions, please present them. (I have above.) But it strikes me as a bit silly to assume that someone cannot present informed positions merely because he is currently operating as a journalist.

My problem with Bush's proposal to go to Mars is not that it is unworkable. It is based on the fact that, as far as I'm concerned, it's just election-year pandering. As are more than a few of his recent proposals.

Posted by raj at January 18, 2004 04:20 AM

"No one is going to use a nuclear upper stage on a launcher"

Really? Why not?

What possible real world difference could there be between a booster nuclear rocket upper stage which ends up in orbit and a nuclear rocket which is "only powered up after they're in a sufficiently high and stable orbit"? There is no difference. No difference in crash risk, and no difference in world wide fallout pollution.

If the only difference is the hope of mollifying the anti-nuclear luddites, then that is also no real world difference. The luddites will still oppose with equal zealousness all nuclear technology for spaceflight. Nuclear reactors which are "only powered up after they're in a sufficiently high and stable orbit" won't make any difference to them. They even tried to kill the Cassini mission to Saturn which only used Radioisotope Thermoelectric Generators, let alone a nuclear rocket.

If we let the anti-nuclear zealots bully us from using nuclear power in space, we might as well give up manned deep space exploration. Without nuclear reactors for power generation and/or propulsion the costs involved will get as astronomically high as the shrillest critics claim.

I'm a political realist. I know the most potent political opposition to manned exploration of deep space will eventually coalesce around the fear of nuclear power. It's suprising to me that is hasn't already happened.

Instead the opposition is still spinning it's wheels with fantasies of trillion dollar costs and paranoid conspiracies of a secret plan to militarize space. It's just more evidence of how abominably ignorant the opposition is.

But if we give in to that fear and ignorance even before it truly ramps up, what hope do we have of final success? We must expect a political battle over nuclear power in space. And we must not appease the ignorance of the enemy by admitting danger where there isn't any real danger.

It could very well be that a nuclear rocket upper stage will not be usefull, and it will never even be proposed. All fine and good. But we should not just abandon it from the start for fear of politics.

Posted by Brad at January 18, 2004 06:26 AM

There is a tremendous difference in crash risk, and spread of nuclear fallout. I wouldn't do it. This has nothing to do with Luddism.

Posted by Rand Simberg at January 18, 2004 07:56 AM

Well, as I said before, I'm no rocket scientist. So explain to me, please, why there is a tremendous difference in the crash risk and the spread of nuclear fallout. And can you quantify tremendous?

The only difference I can see in total fallout is the difference in operating time between an orbital-transfer-only rocket and a combined-upper-stage/orbital-transfer rocket. Or is there something special about the LEO environment compared to the sub-orbital environment?

Unless you assume a nuclear upper stage is less reliable than a chemical upper stage I can't see how the crash risk is any different. The nuclear rocket has to get up from the surface into orbit, whether it is turned on during boost or not. And that's only the risk of the nuclear rocket itself crashing. What about the combined risk for all the boosters launched that are needed to accomplish the mission?

By using only chemical engine stages to lift all the tonnage to orbit, you would have to increase the total number of boosters used. And therefore it seems to me increase the risk of some booster crashing.

Why not take advantage of the nuclear rocket's payload superiority for only those flights the nuclear rocket is launched up to orbit?

But, hey, what do I know. I'm just a dilettante.

Posted by Brad at January 18, 2004 10:46 AM

While I cannot speak for Rand, I've read him enough to infer that he was speaking of the overall risk inherent in a crash of an active nuclear upper-stage, not that an upper-stage is more apt to crash than a chemical upper-stage. That is, to me, reading Rand, "crash risk" refers more to the risks involved "in the event of a crash", not the risk of "a crash being caused or involved".

I'm not a rocket scientist either, but I would assume (however rashly) that if an ACTIVE nuclear reactor (creating energy for thrust as an upper-stage) were to malfunction and crash into the earth, it would likely create a hazard much greater than if any of the individual pieces used to build the reactor in space were to crash to the ground.

Hopefully the difference in interpretation of Rand's use of the term "crash risk" is the only thing separating you from this viewpoint, but I cannot make anyone accept anything that I say, especially given my (lack of) credentials.

Posted by John at January 18, 2004 06:56 PM

Regarding nuclear upper stages:

A reactor that has never operated (or a bomb that hasn't gone off) is not very radioactive, much less so than the radioisotope thermal generators for deep-space probes. And the fuel assembly could be hermetically sealed to survive accidents intact.

But once the reactor has operated, the spent fuel becomes highly radioactive isotopes of other random elements, some of which are gaseous and relatively hard to contain. And the nuclear fuel assembly must be exposed with excellent thermal contact to the reaction mass flow while the engine is running, so the nuclear fuel can't be as well protected then.

So if you're gonna crash a nuclear reactor core, please do so before you turn it on.

Even the Russians used to boost their nuclear reactor powered spy satellites to high, long-lifetime orbits when they reached end of life (the one that crashed in northern Canada was accidental I think).

Posted by Tom Mattison at January 19, 2004 12:45 PM

Yes, what John and Tom said.

Posted by Rand Simberg at January 19, 2004 03:41 PM

regarding the risk of nuclear upper stages

I see the point, but I am still skeptical. A nuclear rocket is not the same as the Soviet nuclear reactor powered satellites.

A power reactor would operate for months, if not years building up radioactive decay elements from the fission process. A nuclear upper stage would only build up decay products for a period of minutes during the upper stage burn placing the rocket from sub-orbital flight into LEO. How much worse could that be than the commonly used RTG?

As for crashworthiness, how do you send up a nuclear thermal propulsion rocket with the engine in partial disassembly? NERVA didn't have any feature like that, SNTP doesn't seem to and niether does the MITEE.

But, live and learn I suppose, I defer to the experts.

Posted by Brad at January 20, 2004 03:57 AM

followup - interesting links and info

http://www.friends-partners.ru/partners/mwade/lvs/timtitan.htm

I found a link to a 1992 study for a nuclear upperstage Titan, called Titan Timberwind.
63 metric tons to orbit! At least the DOD boys didn't think a nuclear upperstage was too risky.

And here is another interesting link to various NERVA upperstage studies. The Hyperion study of 1960 is especially interesting. 145 metric tons to LEO while using less than one third of the liftoff mass of the Saturn V!

http://www.astronautix.com/lvfam/nerva.htm

Also, that Soviet radar ocean surveillance satellite that crashed into Canada, was Cosmos 954 which crashed in 1978.

http://www.hc-sc.gc.ca/hecs-sesc/neprd/nep-events/cosmos.htm

Posted by Brad at January 20, 2004 05:03 AM


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