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« They Still Don't Get It | Main | Attack Of The Reptiles »

Enabling Versus Enhancing Technologies

There's quite a bit of discussion in this post about NASA's role in general, and particularly in technology development.

Reader "Tristan" says that:

The two key problems of space travel have yet to be solved: inexpensive access to LEO, and a way to get around in deep space quickly. Both require high-risk, long term research to produce breakthroughs in propulsion.

While these are two key problems, the former doesn't "require high-risk, long term research to produce breakthroughs in propulsion." As Andrew Case points out, correctly, in a later comment:

I have to disagree with Tristan on the propulsion issue. No new breakthroughs are needed in the basic technology of propulsion. We just need to take technologies already known to work and figure out ways to make them cheaper, more efficient, and more robust. Up to a point NASA can do that, by research programs aimed at ferreting out the various ways in which rocket engines can degrade and fail. Even better is if the power of the market can be brought to bear. History shows that markets are very effective at reducing the costs associated with a given technology.

Technologists often refer to "enhancing technologies" and "enabling technologies."

The former improve systems, in terms of cost and performance. The latter allow them to be built at all. Of course, the definitions are dependent on the context of the mission being carried out, and no technology falls purely into one box or the other, but it's a useful distinction.

For going to Mars, enabling technologies are required to make it practical (some of which I mentioned in the linked post (e.g., nuclear propulsion, or capability to manufacture propellants from the Martian atmosphere). But for earth to orbit, it is possible to achieve dramatic cost reductions without new technology, unless you define vehicle design integration and development as a technology per se. That's because the cause of high launch costs isn't lack of technology, but lack of activity, and vehicles designed to be flown at a high flight rate (and such vehicles can indeed be designed with today's materials and propulsion, but no one has made the investment to do so).

I make the distinction because it helps us prioritize NASA's potential role. It is useful for the agency to be working on enhancing technologies, but it's essential for them to be working on the enabling ones. That's how the resources should be allocated, if they're limited (as they are, of course).

NASA has been spending (and sadly, squandering) entirely too much money on launch technologies, and altogether too little on deep-space and planet-settling technologies, though the former aren't needed as badly and can be funded by the private sector, whereas the latter are vital, with no apparent near-term payoff.

Posted by Rand Simberg at August 22, 2003 02:53 PM
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"But for earth to orbit, it is possible
to achieve dramatic cost reductions without
new technology"

I believe it; space right now is a boutique industry, with the exorbitant unit costs that go along with that. But let's take a look at just how far we have to go.

A state-of-the-art Airbus A3XX airliner carries 800 people, and weighs 1.2M lb. That's 1500 lb per person. Assume a one-way airline ticket costs $300. Do the math, it comes to 20 cents per pound, per trip. I don't know if an orbital vehicle will need more overhead per person or less, for structure, fuel and life support, but I figure a commercial aircraft gives a good starting point.

In the early days, a ticket to heaven can cost a lot more than one to Buffalo, say $30K. That equates to $20/lb. Do any of the commercial LEO ventures have a plan to get to $20/lb? Is that even above the fuel cost of achieving orbit, using a COTS rocket engine?

Never mind, assume someone does it. Now, what's the size of the market? How many people will pay $30K to go to LEO? Will there be casinos? How many people will go a second time? Remember, we need lots of trips to amortize the costs.

I hear politicians talk about the "wealthiest 1 percent". That's around 3 million Americans. If 10% of them buy a $30K ticket, that's 300,000 passengers. At 100 people per trip, with ten vehicles, that's 300 trips (you better build at least 10 vehicles, or you'll pay boutique costs for them - really, you'll need hundreds to get to aircraft-like costs). At one trip per day per vehicle, that's ten months, and $9B in revenue. Then you start taking Japanese and Germans.

I guess it could work, if a market emerges, or if costs go down more and demand goes up. But I wonder, with today's rockets, what's the fuel cost to put 1 lb into orbit, assuming the fuel all costs around as much as gasoline (say $1/gal)?

Also, when I said "two key problems", I forgot about a third: getting down. What good stuff can we build the vehicle out of so that it survives reentry consistantly? Shuttle tile is pretty good, but fragile and high-maintenance. Is there something else? Or is there a better way to use silica than how NASA is using it now? Does more scale help? Even for colonization (one way trips), getting down matters, so you can get the vehicle back and reuse it.

Posted by Tristan at August 23, 2003 12:15 AM

Do any of the commercial LEO ventures have a plan to get to $20/lb? Is that even above the fuel cost of achieving orbit, using a COTS rocket engine?
It's roughly double the cost of oxy-kerosene with present-day COTS tech, but the answer changes with time and markets (usually going lower); Henry Spencer discussed it at length here.

Posted by Troy at August 23, 2003 01:52 PM

Thanks for the link, Troy, that was interesting.
It says basically $10/lb, fuel cost to orbit.

Jet-A fuel costs around $0.80/gal (avg over 4 years).
A 747 weighs 0.87M lb, carries 524 passengers, and takes 57,285 gal of fuel. That's a fuel cost of $45,828 per flight. Assuming $300/passenger, the airline gets $157,200, or 3.43x the fuel cost. Assuming comparable weight per passenger (1,660 lb), my ticket to LEO will cost around $50K.

Now let's build me a casino/hotel for my 2 week vacation. Assume it weighs 1,000 lb per person, and holds 10,000 people (total 5000 tons).

An Airbus A380 freighter weights 1.3M lb, carries 0.335M lb, and holds 81,890 gal of fuel. Fuel cost to haul 167.5 tons is thus $65,512, or $390 per ton (19.5 cents / lb). The loaded, fueled plane weighs 3.88x the cargo weight. At $10/lb, the fuel cost to orbit is $20K per ton.

5000 tons * $20K * 3.88 = $388M to orbit the hotel. Assuming $1000/night/person, it rakes in $10M per day at full occupancy. The launch is paid for in 39 days - not bad.

My two week (14 day) vacation costs $64K, not counting gambling losses and food. Maybe this isn't so far fetched after all.

Now let's say we dispense with some amenities, and get the passenger launch weight ratio (craft to person) down to 3.88x, like cargo (it's 9.22x for a 747). That brings the fuel cost to launch a person to about $7000 (assuming 180 lb avg). The spaceline has to make around 3x that to stay in business, or $21K. So now my vacation costs $35K. But I don't know how you'd bring the weight ratio for passengers down to cargo costs - people need seats, and being oddly shaped, they don't pack well.

10,000 people cycling in every 2 weeks is 260,000 passengers per year. Given 100 hotels, that's 26M passenger trips per year. I don't know how you get scale economies with that low a number, and I don't know where you find 26M people per year who want to spend $35K to $64K on a 2 week vacation.

I still think some breakthrough technology is needed to make this work. I say breakthrough because the fuel cost to orbit with chemical fuel derives from physics and existing scale economies in the fuel industry, so it ain't likely to go much lower.

But it doesn't look as nuts as it did last night.

Note: this analysis is based on tourism, because that's the only viable near-term business I've seen proposed for space travel. If there are others, let me know!

Jet-A fuel cost:
747 Passenger Jet:
A380 Freighter:
Fuel cost to orbit (Troy's link):

[end rant]

Posted by Tristan at August 23, 2003 05:59 PM

Oops, I posted my comment to the wrong blog! I meant to post the followon from the next day, I'll re-post there.

Posted by Tristan at August 23, 2003 06:01 PM

Oh wait, I'm just confused. I posted to the right place after all, duh ;-)
Also, my Jet-A fuel cost link was wrong, it's:

Posted by Tristan at August 23, 2003 06:06 PM

As usual, Rand helps put things in focus with this post in regard to how we determine what role NASA should play. However, I do take slight exception that enabling tech is required for Mars. Yes, it would be nice to have better engines to make the trip shorter and safer. I think good research has been and continues to be done in this area. But, critics of putting people on Mars seem to say economics is the limiting factor - we'd have to build the thing to do it, but we already have some good ideas about how with known technologies.

While I would like to see hotels in orbit (or lagrange point) the exact same economic (and for space hotels even more valid) argument would seem to apply. If you're going to spend half a billion dollars with an eye only on ROI, then you're not going to spend a dime for anything off planet. It just doesn't make economic sense when better investment opportunities exist.

So space is still about vision folks... not economics! The economists will come later to explain why it all made sense to do the thing they will have certainly claimed made no sense to do before hand.

To make this economic vision come true means we need a reason to continually go into space. A colony that is mostly capable of self support would do that. The moon can't do that because it doesn't have the diverse chemical makeup that is required for living off the land. With the exception of aerobraking, any tech. designed for putting habitats on the surface of Mars should work for putting things on the Moon too, or anyplace else in this system for that matter. So let's get behind the idea of going to Mars because we can, it will be sustainable, and cheaper and better systems will follow. We just need to open contracts to any company that wants to provide products for the endeavor.

Posted by ken anthony at August 24, 2003 09:14 AM

The moon can't do that because it doesn't have the diverse chemical makeup that is required for living off the land.

The only thing that the Moon lacks in serious abundance is nitrogen, which is easily shipped as ammonia, and recyclable. All else can be brought in from earth or asteroids.

Mars has a tremendously long supply line and a deep gravity well.

But as I said, I don't want to get into the relative merits of one location over another, because that always ends up, like launch system design, being a theological discussion, and an unresolvable one. The goal of our space policy should be to make all of these options...well...actual options, for all who wish to pursue them.

Posted by Rand Simberg at August 24, 2003 06:55 PM

If you can achieve launch costs of $100/kg or $220/pound, shouldn't solar power sats be an easy way to have a non-boutique launch and lots of them. As well as making money too.

Posted by Chemist at August 25, 2003 07:15 AM

No, there are a lot of issues with powersats beside launch costs. It's not a market I would bet on.

Posted by Rand Simberg at August 25, 2003 08:28 AM

The liftport people certainly think so. One of the things that is absolutely critical to space business is the need to raise our sights economically. We can poke around for quite awhile with terrestrial resources if we're willing to consign the 3rd world to permanent energy starvation. If you bring them into the global system and create a situation where they're going to have practical 1st world style energy appetites, you get into engineering problems. There just isn't enough terrestrial energy available.

Solar power stations then become not only a competitor in the energy market but a vital necessity to meet demand. Fortunately for space commercialization, eliminating the 3rd world seems to be a WoT priority (see Barnett's new rulesets work).

Posted by TM Lutas at August 25, 2003 01:28 PM

"...a theological discussion, and an unresolvable one."

If it's not resolvable, where does that leave us? I think a significant part of the problem is one of focus. With everyone championing their own position you get no momentum leading to any results; instead, we get 3 shuttles (minus calamities) for the next 20 years and the ISS Albatross.

As much as we may hate the JFK model and its resulting aftermath the fact is it did achieve it's incredible goal (even if it was the wrong goal.)

"Mars has a tremendously long supply line..."

That's what makes it preferable to camping in our own back yard. Being three days away means never developing any type of self sufficiency. Frankly, I think not going to Mars immediately after Apollo is why we don't have a real space program today. Kennedy got one thing right, we do it because it's hard!

The goal is not to plant flags. The goal is to colonize... colonize!!!

"...and a deep gravity well."

Which is perhaps a good balance between being able to launch from it, and providing enough gravitational stress to maintain physical health.

It has an atmosphere, water and a reasonable temperature for cripes sake. Show me where else you will find that.

This isn't a religious argument... these are just facts.

The time to go back to the moon is when we are ready to build something there or perhaps to give the Mars astronauts there sea legs. But the goal should be Mars and I just can't see how anyone could be so blind to that fact.

Come to think of it... I guess people aren't blind to that fact... regardless of what you think of it, the Chinese have indicated that going to Mars is one of their goals.

Posted by ken anthony at August 25, 2003 05:26 PM

Kennedy got one thing right, we do it because it's hard!

No, sorry. That's an absolutely mind-bogglingly dumb reason to do something. There is no value to doing something just because it's hard.

It's hard to dig a hole ten miles deep and two miles wide. Let's do it!

If it's not resolvable, where does that leave us?

It leaves us looking for a policy that can satisfy the goals of all of us, rather than just the goals of those who have a lech for Mars.

Sorry, but I don't really care about Mars. I can build everything I need on the moon, or in free space, and am not enthused about leaving one deep gravity well just to have to fight my way in and out of another.

You are exhibiting what Gerry O'Neill called "planetary chauvinism." That's exactly why it's a religious argument. There's no right answer--only various individuals' preferences.

This is America. We have to have a space program for individuals, not collectivists who force everyone to go along with what they decide is best.

Posted by Rand Simberg at August 25, 2003 05:40 PM


When you respond that it's hard to dig a trench you miss the meaning. You do something that is hard because it expands your capabilities AND is worthwhile. To do something just because it's hard is just plain stupid, and JFK wasn't saying that.

"I don't want to get into the relative merits of one location over another..."

Fair enough, but what is this goal we all have in common? If we could put it into words it may be easier to determine the steps to get there.

One goal, which is certainly not THE goal in my mind, is cheap access to space. As Pournelle has said, Earth orbit is half way to everywhere. We can agree that cheap access is a common goal. As you've reported many times, private groups are working toward that goal with different business models and I support these efforts along with you.

However, you jump the gun when you accuse me of chauvinism. I think my past comments give at least some evidence that I've considered other destinations. It's not a gravity well that attracts my attention to Mars (although, given the state of our medical knowledge, Mars gravity seems like a bonus in terms of transitioning to a space ecology.)

We have plenty of experience with microgravity and what we've learned is that it's bad for us. So taking a step that leaves us with that huge unresolved problem is stupid, no matter how much we'd like to stake our claims in the asteroid belt.

Another thing Pournelle has written (you I sure have a copy of his book, 'A Step Farther Out') is that he doesn't just want to live... he wants to live in style, with abundant energy and resources. I think he was on to something.

So I see the goal as expanding our boundaries into this solar system. Orbiting the Earth was the first step. Landing on the Moon was the second. NASA has decided that the ISS Albatross is the third. So be it. I propose that Mars is the next logical step even if others don't see it.

After that the asteroids and other bodies in this system. A colony on Mars will encourage better engine designs faster than anything else I can think of.

Cheaper access to space for small payloads is already in the works. But without large payloads going somewhere (and where really besides colonies on Mars... I ask you, suggest any more reasonable place?) you will not see cheap large payloads. Why build heavy lift if you are never going to use it?

Hotel L5 is a fantasy until we have heavy lift capability. You can't get the volume of customers to justify the costs otherwise. Who's going to invest in heavy lift without first having a destination. It's the classic chicken and egg.

Please Rand, I say this all with respect... not caring about Mars is a huge strategic mistake.

As for your last point... I'm not a collectivist, a communist or perhaps any ist at all, except perhaps an enthusiast. I want to see people have to freedom to do what they want and go where they want and pursue their individual dreams.

I think we've stumbled and I'd like to see us pick ourselves up and move on. Actually, I think it's inevitable.

Did I mention, I don't get to go? But I think humanity needs to. The cradle is a rockin.

Posted by ken anthony at August 25, 2003 10:33 PM

One goal, which is certainly not THE goal in my mind, is cheap access to space.

It is THE goal. Once that goal is accomplished, all of our other goals become possible, and we don't have to talk the taxpayers into helping us achieve them.

You don't seem to get it. You like Mars.


I don't care about Mars (at least not as the Holy Grail)--I'm interested in other things. I'm not fighting to escape one gravity well just to stick myself in another.

I've thought about these issues for thirty years, and the probability is vanishingly small that you're going to come up with some new argument that's going to somehow suddenly magically make me see the light, and say, "Ken's right! How could I have been so blind? Mars, of course!" So please stop wasting your time and my bandwidth and disk space attempting to do so.

We need policy that allows us both to pursue our dreams, rather than having to make a one-size-fits-all choice.

Posted by Rand Simberg at August 26, 2003 08:40 AM

My point is that cheap access is a means to an end, not the end itself. Perhaps I'm just looking too far ahead.

We don't disagree about freedom of choice.

Time will tell how blind any of us are. If history is any guide the vast majority, of which you and I are likely a part, do not see the future very well.

As a boss likes to tell me, preaching cheap access is like being for Mom and apple pie. Who isn't for cheaper access?

I hope you realize that I respect you and support your goals, but that doesn't mean I have to be in lock-step agreement with you on every issue. I hope you are a big enough man to handle it. We shall see.

Posted by ken anthony at August 26, 2003 12:27 PM

Cheap access is not just a means to an end--it's a means to many ends, and it's an essential one. Until we've figure out how to skin that cat, it doesn't make much sense to fantasize about Mars, because the mission is going to depend very much on how big and how cheap the pieces are that will be going up.

Who isn't for cheaper access?

Many people, notably much of the existing aerospace industry, which is making a nice living off of expensive access.

I (don't) have to be in lock-step agreement with you on every issue. I hope you are a big enough man to handle it.


I'm not sure why you think that I would expect you to be in lockstep agreement with me on any issue, let along every one, nor do I know what would constitute evidence of my "not being man enough to handle it." What would my "not handling it" look like?

I actually find this amusing.

Posted by Rand Simberg at August 26, 2003 02:23 PM

Glad to amuse... I was worried I might offend you.

I'm a regular reader, enjoy your perspective and generally agree with your viewpoints. I think you have a great sense of humor and irony, plus the ability to teach a subject with clarity. I wish I had some of those same abilities. One skill I do have is the intuative ability to see things early. It's not that I have any love for Mars, but I found Zubrin's book entirely persuasive, if not in all the details.

As for the aerospace industry, actions speak louder than words. You know they'd lie through their teeth if you put the cheap access question to them. Which is why it's a Mom and apple pie issue.

We agree. Completely. That access should be cheaper, so that more can play. The question is how to achieve it? I believe there is more than one answer and that they are not mutually exclusive. X-prizes? Great. Less regulation. I'm all for it.

But lets give credit were credit is due. While we might not like it, the bureaucrats involved figured out that if you want to keep the shuttles flying they had to have a destination, e.g. the ISS Albatross.

I'm not and never have suggested a tax funded government program of any kind. That's a knee jerk assumption that some people have made. I don't support it and I've never said it.

Back to the question, what will achieve it? Hotels in orbit? I'm skeptical. Would I like to see it happen? Sure. Will it be the engine that drives down costs? I don't think so.

Suborbital joy rides? Actually, I think that has a lot going for it. However, again I don't see it as the driving force.

A research base on the Moon? If we actually had a need for such a thing this would put pressure to develop better launch capabilities.

A colony or permanent settlement anywhere (in a gravity well or microgravity environment does not really matter for the purpose of this point)that is not in our immediate back yard... This would require regular supply runs. A regular, decades long commitment will get people serious about finding cheaper solutions to the access issue.

If that last possibility proves to be the real driving force, it begs the question... where? Where, given our present understanding of human physiology. Where is a settlement most likely to establish itself.

The Moon is out, because it's too easy to abandon any commitment we make there. Where ever it is, it has to be the right distance away, not too far and not too close (in time rather than distance.) This is entirely determined by how independant the settlement is capable of being.

...I begin to realize, this discussion must bore you if you truly believe that the means is the end. You don't believe that focusing on a destination will give any impetus to the process. I apologize if this is a mis-characterization, but that's the impression you've given me.

I think humans need a focus to accomplish things, and I think saying we need cheaper access leaves people having consensus but no action. I think that's a real problem.

Posted by ken anthony at August 26, 2003 06:16 PM

...I begin to realize, this discussion must bore you if you truly believe that the means is the end. You don't believe that focusing on a destination will give any impetus to the process.

No, I don't believe the means is the end. We just disagree about what the end is. To me, the end is enabling everyone to get off the planet, to pursue their dreams. To you, apparently, the end is Mars. I would submit that your "end" is too narrow to be either useful, or politically practical.

If we focus on a single destination that not everyone agrees with, we won't get support for the resources that such a focus requires (not to mention the fact that it's immoral to force someone else to subsidize your personal fantasies).

Posted by Rand Simberg at August 26, 2003 07:32 PM

"To you, apparently, the end is Mars."

Then you've entirely missed my point.

Posted by ken anthony at August 26, 2003 07:42 PM

Perhaps, but it's understandable, since you've been arguing for Mars for the entire thread...

Posted by Rand Simberg at August 26, 2003 08:56 PM

Well, you are certainly right about that. While I think it's the next logical step, I believe ultimately our goals are probably the same...
freedom from being tied to one planet. Freedom in all its manifestations. Considering that man has dominated man to his injuring since the beginning of time... now there's a real fantasy. But sometimes I'm an optimist.

Posted by ken anthony at August 27, 2003 02:20 AM

Ken apparently believes that going to mars is one of the great way to achieve your stated goal, Rand, and doing so also enable all the other ends.
The logic, simply put, is: get a destination up there, millions of people will want to get there, so that someone somewhere will come up with a magical answer to get there cheap.
I think there are huge leaps of sheer wishful thinking in this logic, and it wont work. Our Albatross Space Station is a living proof of that.

A lot of subjective opinions thrown in for a good measure too. Moon is too close ? Lacks resources ? So why Mars, why not upper atmosphere of Venus ?

Ken, you are trying to construct a similar false premise like the one that exists. Current one is "science". "We are in the space for sake of science". You are proposing public should be told we do it for sake of going to Mars, so a lot of good support will gather beyond this effort, and we can sneak in push for CATS under the radar so in the end we will have solved all the problems and opened the path to future. It wont work this way. No CATS will come out of this, no solar power stations, no asteroid mining, no off-earth colonies ( a tiny short-lived Albatross base perhaps, until next accident )

Posted by at August 27, 2003 09:24 AM

Magic? Hmmm... what did Clark say about magic? No, I'm not at all suggesting a magical solution. To misrepresent my position as such in order to demolish it is called??? [hint: one of Dorothy and Toto's friends.]

If we are going to spend money (almost as much as the Apollo era today) shouldn't we have something to show for it? You know, beside a killer winnabago?

Goals promote achievements. Destinations clarify goals. Accomplishments can be build upon. Or you can do like the government and throw away billions after investing in the development of new enabling technologies.

I've been accused of being an immoral socialist because money that I have no say in, is being spent with no accountability and I have the nerve to suggest there might be a better way of spending it. I'd be happier if they simply stop spending it. That way it wouldn't draw the air out of private ventures that would pick up the slack (although to get things moving might require more than a few private companies alone could afford.)

I'd like to see some real accomplishments. Perhaps even in my life time. It doesn't have to be my vision. I'll settle for anyones vision that makes the least bit of sense.

Better people than I have made the case for...

Posted by ken anthony at August 29, 2003 06:24 PM

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