Monday, November 15, 2010

First Stage


We can already do, and have done, a great deal in space. We have scouted all the major planets, landed on the Moon, Venus, Mars, and Titan, and dropped among the clouds of Jupiter. We have passed through the heliopause into interstellar space.

The International Space Station has shown that crews can live and work aboard a spacecraft for years, with no emergency requiring evacuation to Earth or urgent support from Earth.

This is the primary requirement for human interplanetary travel. At a fundamental level, add a drive bus and you are good to go. Nor is any really major handwave needed for a solar or nuclear electric drive capable of reaching Mars in 2-4 months. (If Mars leaves you cold, adjust for the destination of your choice. It will probably be colder.)

All you need to wave is a check for $200 billion or so, to pay for developing your vehicle and mission from conceptual design to flight testing and human spaceflight certification.

Do not expect to get there for much less than that. The Airbus A-380 and Boeing 787 Dreamliner - commercial products of private industry, working in a mature kindred technology - each cost some $15 billion to develop. Such projects simply require an enormous amount of costly engineering work and one-off fabrication.

SpaceX and Scaled Composites do not prove otherwise. They prove only that the ecosystem has a place for small, agile skunkworks that can underpay top talent to work on exciting projects. Even technologies like 3-D printing won't really change the equation, because initial space costs are mainly engineering costs, and engineering at the cutting edge remains a craft trade.

But for a trillion US dollars or equivalent, give or take, you could probably build yourself a decent start on the classical rocketpunk midfuture: a second generation station with spin hab; outposts on Luna and Mars with ships to serve them; a human mission to Jupiter; altogether up to a few hundred people living in space. Call it the Clarke-Kubrick vision, though it could equally well be called the Ley-Bonestall vision.

The specifics are all freely subject to change. Commenters have challenged such rocketpunk-era verities as an orbital station as transfer point, and of course there are debates about where we should actually go and in what sequence. But this infrastructure, or something comparable, is the trillion dollar admission ticket to everything else.

A trillion dollars is a lot of money. More precisely it is a staggering, awesome, incomprehensible amount of money. It might end up being more than we are willing to spend on space travel in this or any century. But it is not impossible money. It is comparable to NASA's cumulative budget from its beginning to the present day, and about twice the cost of another public transportation system of similar age, the Interstate Highway System.

I am very doubtful that the private sector can or will take us into deep space on its own. But the largest corporations have revenue and market capitalizations of a few hundred billion dollars, so - given persuasive enough reason to believe that it would be profitable - it is not utterly out of bounds to imagine a global commercial consortium raising a trillion dollars.


The time scale of space is really, in large part, the money scale of space. If space spending in the later 20th century had remained at Apollo levels we might well have had the Clarke-Kubrick vision on schedule in 2001. At the levels of space spending and resulting space progress that we have seen over the last 35 years it is about in line with what we might expect for 2101.

It could as easily be 2071, or 2171. (Or never.) Given a sufficient (hand)wave of great power muscle flexing it might be 2031. But I will use 2101 as my conservatively optimistic benchmark. This presumes that we continue going into space in the same rather muddled, low-keyed, but persisting way we have since those heady early years.

So. At the start of the 22nd century, or broadly comparable date of your choice, we have regular interplanetary travel, but still very little of it, and what there is is very expensive.

Production jetliners, as I've often mentioned, cost about $1 million per ton at the factory ramp. But commercial jets can be sold for that price because Boeing and Airbus expect to build several hundred of them, spreading out the development cost and permitting semi-mass production efficiencies.

The first generation of interplanetary ships will be handbuilt prototypes. The second generation will still be largely handbuilt, though modular construction will begin to allow limited production runs of standard hab pods and the like. So a ship capable of carrying 10-20 people on an interplanetary mission, with departure mass of 1000 tons, dry mass 500 tons, gross payload 200 tons, might cost $5 billion assembled on orbit and ready for loading.

Adjust ticket prices accordingly. Suppose that your ship can make 10 round trips to Mars in a design service life of 25 years, so charge each round trip $500 million up front. Add another $500 million for 500 tons of propellant lifted from Earth - don't expect launch cost under $1 million/ton at the modest traffic volume of the early interplanetary era. And don't expect to get it from anywhere else, not at this stage.

So (simplistically!) $1 billion for our ship to make one round trip to Mars. It carries 20 people in transport configuration, so that will be $50 million, please. For a first class ticket $100 million - not for the caviar and steaks but the chef and stewards.

I confess a personal weakness for Pullman class interplanetary travel. The Realistic [TM] space travel alternative of doing basic preventive maintenance on microgravity toilets for 200 million miles would get old even faster.

But a note of practical caution to my libertarian minded readers. A world with so much loose money sloshing around the economic elite that it can send a Pullman car full of billionaires to Mars every two years is also a world with thousands of Paris Hiltons. Never mind poverty and social injustice. At some point sheer annoyance will bring out the guillotines.

Ahem, back to the point.

What happens after the early interplanetary era, in the second century or two of space travel, is much more conjectural, even by the necessarily naive standards of this essay.

Personally I think that by far the most likely human space future, through the 22nd century and well beyond - in short, through the midfuture - is far more like Antarctica than Heinlein: a chain of scientific and technological outposts, gradually extending outward.

Space is remote, costly to reach, difficult to live and work in, implacably indifferent to human life, and filled with things that fascinate us.

It is probably not filled with McGuffinite.

The human Solar System may well belong to artists, not writers. A deep space effort like this provides all of the lovely images - dawn on Mars, gliding through the rings of Saturn, everything Chesley Bonestall imagined and more - but not many plot lines, and certainly not the favorites among this bloodthirsty audience.

Which might be a feature, not a bug: a Solar System touched more by our aspirations than our failings.



That is probably not what you want, but I will save other possibilities for another post.


The image of an ESA concept for Mars exploration comes from a Romanian space website.

225 comments:

«Oldest   ‹Older   201 – 225 of 225
Thucydides said...

The Jules Vern "nuclear cannon" is not capable of firing a payload at the speed advertised, but is theoretically capable of launching huge payloads into orbit: http://nextbigfuture.com/2009/03/underground-nuclear-tests-salt.html

Milo said...

"500 grams per kilowatt"

Which is not nearly enough. As I pointed out, the performance you implied requires less than 10 grams per kilowatt... that's 10 grams of ship, the reactor is going to need to be even smaller.

We do not already have enough energy available to solve the space problem through brute force.

Tony said...

Re: Anon

As you apparently don't know, it helps if you actually live in reality.

If you have a space fountain, you don't need a nuclear cannon.

If you try to make a nuclear cannon, you're an irresponsible actor who will be suppressed. There's no way that a gun that can release a ULCC sized projectile would not be able to contain the inevitable radioactive fallout. (Before you go there, Next Big Future is the biggest pile of pseudoscientific bullcrap.)

Scott said...

"You left out the mess deck, the laundry space, the engine rooms (which are work spaces), offices (also workspaces), parts of the missile compartment not used for berthing (workspace plus enough space to actually jog), and other miscellaneous spaces not considered "habitable". Yeah, it's close aboard ship, and even closer aboard a submarine, but nothing like current spacecraft designs. It's okay, you don't have to fight it."
I'm making a point that spacecraft *as presently designed* are not suited for prolonged human habitation.

How big is the international space station? 837m^3, according to wiki. It normally has a crew of 6, for 139m^3 per person, counting all the working spaces and the space occupied by equipment.

If you include all the working spaces on an ohio-class, you're looking at a cylinder 42 ft in outside diameter not more than 350 feet long. Yes, overall length is 560ft. There are tanks at the ends, and tanks and a reactor compartment in the middle that take out a lot of volume. Structural frames are thick, so you're down to an interior diameter of 34 feet. Call it 10m diameter and 100m long, but I'm sure we're still over-estimating. I spent a long time living on those boats. That gives a volume of 7854m^3, divided by 120 people (60 or so on watch, and the other 60 coming off watch). Call it ~62m^3 per person, or about 222 sqft per person. That doesn't sound right at all, but it is what the math said.

I think you could get away with ~15m^3 per person living space in gravity. That pretty much defines the size of your centrifuge. Once you have a centrifuge defined, then a lot of the rest of the ship 'designs itself'.

Now, back to our buddy anonymous... That 10 megaton detonation is going to turn anything other than water into a thin smear on the back bulkhead. Too much acceleration.

Go look at the Atomic Rocket site: http://www.projectrho.com/rocket/enginelist.php#Orion . Orion is great for heavy lifting. Too bad that each launch is the equivalent of one Trident 2 missile's business end. Using numbers from 1959, we're talking about 200 individual detonations ranging from 150 tons to 5000 tons. And a total in-atmosphere release of 100kt. Try it, I'm curious to see how long before every nuclear-armed nation decides to 'come have a talk'.

I crunched the numbers for that '96 hours to Mars' they did in the pilot of Space: Above and Beyond, using the continuous-acceleration formula from Dreampod 9's Jovian Chronicles game. That's a continuous acceleration of very close to 1g, 6 days is about .5g due to the squaring. There's not a rocket in existence, even the Orion, that can do that mission. The delta-vee just isn't there.

Tony said...

Scott:

" Call it 10m diameter and 100m long, but I'm sure we're still over-estimating. I spent a long time living on those boats. That gives a volume of 7854m^3, divided by 120 people (60 or so on watch, and the other 60 coming off watch). Call it ~62m^3 per person, or about 222 sqft per person. That doesn't sound right at all, but it is what the math said."

Let's see...

The volume of a cylinder is:

v = height * pi * square(radius)

pluggin in tha numbaz:

v = 100 * 3.14159 * square(5)
v = 314.159 * 25
v ~= 7,854 m^3

Okay so far.

Wikipedia gives the complement of an Ohio class submarine as 155 (15 O, 140 EM). Who is this extra 35 non-watchstanders? Anywho:

7,854 / 155 ~= 50.7 m^3 per man.

"How big is the international space station? 837m^3, according to wiki. It normally has a crew of 6, for 139m^3 per person, counting all the working spaces and the space occupied by equipment."

Seems like they got more room in space, right? But we're not talking about the ISS, which masses 370 tons. We're talking about much smaller interplanetary spacecraft. NASA has figured that the optimum habitable volume per person, for missions 6 months or longer, is 20 m^3. That's what I was talking about. And your sub has a lot more than that.

Geoffrey S H said...

@ Tony:

I agree that NBF is somewhat... optimistic in its predictions (last week they said something about how fusion was only months away or something).
Nevertheless, its not completely useless, if only providing some useful concepts one could mine for ideas.

Remember that many proper scientific publications wouldn't even mention a space fountain or the like... simply because it is assumed that the reader already knows that they are pure handwavium (with current technology).

Marsprojekt, NBF, new scientist (another one), zubrin's ideas... they all have the sum total of zero usefulness (and pretty much the same amount of handwavium) for NASa currently.
IO can't dismiss them all, otherwise there would be nothing to provide aids on how a future with technological developement in space would look like (given how NASA and DARPA are currently obsessed with reusables, ironically their concepts are even LESS useful).

Tony said...

Geoffrey S H:

"Marsprojekt, NBF, new scientist (another one), zubrin's ideas... they all have the sum total of zero usefulness (and pretty much the same amount of handwavium) for NASa currently.
IO can't dismiss them all, otherwise there would be nothing to provide aids on how a future with technological developement in space would look like (given how NASA and DARPA are currently obsessed with reusables, ironically their concepts are even LESS useful)."


Actually, yesterday was a good example of where we are going with NASA. It's not in the direction of reusables. It's in the direction of buying capability from a commercial supplier and letting the supplier worry about the technical details. Turns out it works. Those commerical suppliers may eventually back into reusability of at least some components. SpaceX is trying to reuse their first stage and the Dragon capsule. But they're not putting that ahead of meeting their business commitments.

NASA could even one day, not too far down the road, put heavy lift out to bid. They'd probably only get one bid, from a consortium of Boeing and LockMart, but there's no fundamental reason it couldn't be done that way.

Rick said...

You can have your cake and eat it too in this case, hiring out orbit lift while NASA concentrates its own efforts on reusability, as the least worst alternative option.

Scott said...

Wikipedia gives the complement of an Ohio class submarine as 155 (15 O, 140 EM). Who is this extra 35 non-watchstanders?
My numbers are a little weird because I did not include the ~2m^3 per person for bunks (360m^3) in the living volume, nor did I count the rough third of the crew that was asleep in those bunks at any given time (so only 120ish crew active and competing with each other for space at one time).

The wikipedia numbers are the 'as-designed' specs. During the 6 years I was active duty, Ohio-class regularly deployed with 170, and that number was increasing as the number of Los Angeles-class boats decreased. It wasn't unusual for the Engineering department to be more than 33% overstaffed, allowing them to stand 4-section watch, plus the new guys under-instruction. Figure 2-3 extra officers onboard as reliefs-in-training, and 15+/-5 junior enlisted, all watchstanders or under-instruction.

And that's not counting the inspection teams (typically 10 people) and/or shipyard workers (0-5) as non-watchstanders. However, they *usually* were only onboard for a week or so.

I know, because I was a yeoman who had to prepare the sailing list message!

Thucydides said...

WRT putting heavy lift up for bid, SpaceX has a heavy lift version of the Falcon (Falcon 9 and Falcon 9 heavy), which should be able to compete against Atlas, Delta and Titan class launchers.

Since it is really several Falcon 9 rockets strapped together (and the Falcon 9 is a cluster of Falcon 1 rocket engines under a wider diameter stage), the successful launch of the Falcon 1 provides some assurance they know what they are doing and can actually pull this off.

http://www.spacex.com/falcon1.php
http://www.spacex.com/falcon9.php
http://www.spacex.com/falcon9_heavy.php

Anonymous said...

Hopefully the SpaceX approch will lead to a reduction in cost for space launches, even if only in administative costs. Maybe this will be the start of a new trend in commercial space launches.

Ferrell

Geoffrey S H said...

Not.Going.To.Happen

Space costs are at the level they are despite all attempts to bring them down over a period of 30 or so years.

Afew private companies won't help. I'm sorry, but it would need EVERY Western country plus significant Eastern and South American businesses each having their own astral-plans for privatised space travel.

Can we please stop looking for a miracle in every small private bid?

There simply are not enough.

Anonymous said...

Geoffrey S H;
Hey, if NASA launches a payload on one of their rockets for $30 million (for example) and SpaceX launches the same payload on one of their rockets for $20 million, then that's a reduction in cost...not that you or I could afford a trip on either one, but trends have got to start somewhere and if enough approches in cost reduction take hold, then the accumulated totals of all those different approches might add up to significant cost savings; however, you are right that any one approch, either procedural or technological, will not significantly reduce costs...it is the combined effect of all of these new approches to cost reduction that will bring launch costs down to a reasonable level. This might take years, decades, or even a century or two, but I'm confident that it will happen.

Ferrell

Tony said...

Commercial launch service providers, if allowed to proceed as they see fit, will bring down costs a bit, but not in any game changing way. The largest remaining inefficiency is unwillingness to push the risk envelope -- the actual hardware cost is marginal, even with single use rockets -- and that can only be taken so far. Elon Musk was right that NASA wouldn't have taken the approach his company did to rocket nozzle cracks (field modification by an expert shipped in from the factory). But the potential improvement in dispatch reliability and lowered admin costs has to be balanced against delivery reliability. If the field fix hadn't worked and COTS 1 had a mission failure attributable to the nozzle or the fix, it would have sunk SpaceX and maybe even COTS in general.

SpaceX is a small, agile operation willing to accept those kinds of risks. Other rocket makers and fliers aren't, and if SpaceX starts doing real business, they'll get more risk-averse over time. They'll have to.

Tony said...

Thucydides:

"WRT putting heavy lift up for bid, SpaceX has a heavy lift version of the Falcon..."

When I said "heavy lift", I meant in the Saturn V/Energia/Shuttle-derived HLV range -- 80 tons plus to LEO. Anythign we do along those lines is more likely to be Shuttle-derived than not. So if NASA put the capability out to bid, it would be answered by an industry consortium, not by any one company.

Geoffrey S H said...

80 tons sounds horribly like pure science fiction.
That's only 12.5 launches to get 1000 tons into orbit.

Thucydides said...

I will accept your definition of heavy lift, but that capability isn't in demand anymore. Even ISS modules can probably be lofted on a Falcon 9/Titan class launcher, and the general trend has been for smaller. lighter and more capable spacecraft rather than bigger and heavier ones.

This has been the death of Rocketpunk in general, the need for a person on the spot to run the spacecraft and fix things has generally evaporated. RoBo became the Minuteman III, and Das Marsprojekt became a fleet of tiny automated spacecraft.

Unless Mars Direct is accepted as the plan (which does need a heavy lift vehicle of Saturn V class to make a direct launch to Mars), I think the smaller launchers will do, any Mars spacecraft will be ISS type assemblies with a VASMIR and some sort of powerplant strapped on the back end, easy enough to do with modular construction.

Tony said...

Geoffrey S H:

"80 tons sounds horribly like pure science fiction.
That's only 12.5 launches to get 1000 tons into orbit."


The Saturn V was rated at 118 tons to LEO. Energia was rated at 88 tons. The Shuttle is right around 120 tons fully loaded, but we always bring 100 tons (the Orbiter) back down. 80 tons to LEO is demonstrably achievable.

Thucydides:

"Unless Mars Direct is accepted as the plan (which does need a heavy lift vehicle of Saturn V class to make a direct launch to Mars), I think the smaller launchers will do, any Mars spacecraft will be ISS type assemblies with a VASMIR and some sort of powerplant strapped on the back end, easy enough to do with modular construction."

Not quite. The heavier the lifter, the fewer modules per any given mass of modular spacecraft. Also, larger modules require a lower percentage of mass dedicated to structure and structural/electrical/plumbing/ data interfaces. Finally, fewer modules means fewer critical events -- launches, stage separations, dockings -- which lowers risk.

Thucydides said...

While I agree that engineering wise, a bigger HLV is better, there is also the political and financial risks.

Political in that a new congress or administration might change their priorities, leaving you stranded with a half developed new HLV (Constellation, anyone?).

Financial in that the aerospace companies might not be able or willing to invest in an expensive capability with a very limited market. Falcon 9 and the 9 heavy versions are looking for a "sweet spot" in the market, this size will allow them to compete for satellite launches and other commercial traffic, gaining some economic flexibility and hopefully economies of scale with longer production runs.

Given that environment, it may be less risky overall to accept a smaller module size for the Mars mission. Reusing experience and technologies already used by the ISS is also a big way to reduce risk; Rick has pointed out many times the ISS is a deep space mission lacking an engine...

Tony said...

Re: Thucydides

The large aerospace companies don't see any financial risk in developing HLVs, as long as it's done with the public dime. And it would be, because NASA's manned spaceflight program is the only customer. In that environment, a string of unrelated R&D contracts or bending actual metal that goes to Mars (or wherever) are both just business.

Now, the political risks you mentioned do indeed exist, but we have to remember that the ISS has been built and looks like it will stay in service for another ten years. So it can be done across multiple administrations. It just can't be done in a follhardy, all or nothing manner. That's why I think Flexible Path is a good idea -- one hard thing at a time, and the heavy lifter is the first hard thing, supporting everything that comes later.

Geoffrey S H said...

@ Tony:

I'll check those figures at some point *thinks about sources of astrophysic books*.
Given that I've had some years of being told "Nope, sorry, can't do that" as regards space and the space industry, and hard sci-fi... I will remain cynical on those figures.No offense or anything meant- I'm just being careful here.

Tony said...

Re: Geoffrey S H

Saturn V

Energia

Shuttle (One has to add the rated payload and Orbiter masses together to get the maximum mass that can actually be put on orbit.)

Also:

Skylab (76 tons put on-orbit by a single Saturn V launch)

I understand that a lot of people, most definitely including myself, are skeptical of a lot of things, and are always making a point of it. But we (as in humanity) have managed some pretty decent launch vehicle performances when we were willing to spend the money on it. And that's the real problem -- large launch vehicles and their launch campaigns are expensive enterprises that have to be justified by a mission that no other launch vehicles could handle even remotely as well.

Geoffrey S H said...

Thanks for that, the bibliography at the bottom could prove very useful...

Levitra Soft said...

I will be your frequent visitor, that's for sure.

Anonymous said...

Go read up on the mining of rare earth metals -- the political fighting over them, and the money being spent, and how necessary they now are for things as commonplace as your smart phone and your Ipad. Will a rare earth mining consortium raise a trillion dollars to go to the asteroids or to mine an impact crater on Venus to get the metals? It cannot cost much more than mining deep ocean volcanic vents (the other alternative) and given the environmental hazards in refining rare earths, I think most folks would rather we go to space to get them.

«Oldest ‹Older   201 – 225 of 225   Newer› Newest»