The Space Station as an Interplanetary Transport Vehicle?
Written by Ian O'Neill
The ATV has carried out a series of boosts for the ISS (ESA)
The International Space Station (ISS) is the jewel in the crown of human ingenuity and a testament to the incredible engineering mankind is capable of. The modular human outpost began construction in 1998 and it is hoped the final configuration will be complete by 2010. Apart from orbiting the Earth and the occasional re-boost by the docked Automated Transport Vehicle (ATV) "Jules Verne," the ISS is going nowhere in a hurry. But wait a minute, isn't that what the ISS is all about? Isn't it simply an orbital science outpost? Well it is, but could it be something a bit more dynamic? Some critics cite the ISS as the most expensive waste of time the international collaboration of space agencies have ever been committed to; after all, who needs more zero-G experiments?
Solution: Attach a rocket and a steerage system and behold, we have a huge interplanetary transport vehicle, capable of travelling to the Moon and possibly to Mars. Who needs the Constellation Program anyway…
In an entertaining Washington Post article, Michael Benson discusses something I've never thought about. Rather than letting the ISS gradually fade away to a perpetually orbital retirement and eventual re-entry, why not do something a little more exciting with the football pitch-sized manned outpost? Forget more zero gravity experiments, stop throwing boomerangs around (yes, it came back), abandon the thousandth test on sprouting barley (although the beer might be good), install another toilet and let's get serious. Upgrade the ISS into a full-blown spaceship and let's begin exploring the Solar System in style!
So what's the logic behind this conclusion? The ISS has 15,000 cubic feet of habitable space in 10 modules. It has ample working and living areas with scope for more. It can repair itself (using the Canadian robotic arm, controlled from inside the craft). This creates a more than comfortable space habitat for five permanent crew members plus the occasional guest. The space station has been billed as a "stepping stone" for future missions to the Moon and beyond, but those plans will probably not see the light of day in the ISS' lifetime. Besides, as the Constellation Program shows, "stepping stones" are not needed; NASA is favouring the direct flight route to the Moon and Mars, stopping for lunch at the ISS isn't necessary (besides, it's a waste in fuel and resources).
Also, space stations are not new. The Russians have had a series of seven manned outposts (from the 1971-2001 Salyut and Mir programs) and the US had the 1973-79 Skylab station. There is a huge wealth of data available from the vast numbers of experiments that have been carried out, many present-day ISS "experiments" often appear to be slightly frivolous (i.e. the afore mentioned boomerang tests) when compared with the pioneering observations of the human body in space.
Artist impression of the final configuration of the ISS by 2010 (NASA)
All this said the ISS would be a great candidate for interplanetary travel. Although it might look a little ungainly, in the vacuum of space there's little concern for aerodynamics (besides, for a station orbiting at a speed of 17,000 miles/hr, its shape is hardly holding it back!). It's a tried and tested space-worthy candidate. Plus, the Constellation Program would fit right in. Perhaps the Orion module could be integrated into the station, and the engines from the powerful Ares rocket could be attached for propulsion. If something a little gentler is required, ion propulsion engines are becoming more and more sophisticated. If you're thinking all of this is fantasy, well it isn't. The station depends on "re-boosts" from docked resupply ships (such as Soyuz and the ATV) to occasionally increase its orbit. Back in April, Jules Verne pushed the 280 tonne station nearly three miles higher in only 12 minutes. This was achieved by using the small thrusters on the ATV; imagine if a larger thrust was achieved. Naturally, there may be structural questions hanging over the subject of thrust, but it seems only a small yet constant force is required for long-term interplanetary missions.
The International Space Station could be the ultimate "mother ship," where astronauts live, but small planetary missions can detach and land on the Moon or even Mars. Besides, the ISS is set for retirement in 2016, perhaps it could be reborn and refurbished (in time for the realisation of the Constellation Program) into a new class of space vehicle; not a space station, a space exploration vehicle. After all, it needn't only orbit the Earth…
Original Source: Washington Post
Filed under: Space Station
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July 17th, 2008 at 9:04 pm
Not a terrible idea but there's not not enough radiation shielding for habitation too far beyond Earth orbit. I'm aware of how much or what type of shielding would need to be sent up. Considering the size you'd need a lot.
July 17th, 2008 at 9:53 pm
I'm just assuming, but wouldn't it take an extreme amount of propellant to reach earth escape velocity and then a lot more fuel to slow down upon reaching the destination? Anyone able to figure this out for either/or ion or chemical propulsion methods?
July 17th, 2008 at 9:59 pm
Maybe not so much.
Only one compartment would need to be shielded heavily enough to protect the crew from the kind of heavy radiation that happens in the van allen belt and after solar flares and other high energy events. These events would give the crew plenty of time to retreat to the shielded compartment, and as for the rest of it, minimal shielding would be sufficient.
The payloads to bring the shielding materials to the station would still have to be pretty large, but it's not like you have to coat the entire thing in 15 cm of lead.
July 17th, 2008 at 10:00 pm
My above post was in response to the first one by Cynthia.
July 17th, 2008 at 11:28 pm
Do all these "writers" ever do their homework? How simple it all sounds – attach engine, turn it on and here goes the Moon…
Do you know how much engine and fuel, needed to achieve Earth orbit escape velocity, will weight? How about twice the weight of ISS itself? And there are no stable orbits around the Moon – you will need much more propellant to keep it orbiting the Moon than you need it in LEO…
July 18th, 2008 at 12:15 am
WELL LETS FACE WE NEED SOME NEW IDEAS AND SOLUTION. THIS WHITE ELEPHANT HAS BEEN SWALLOWING HUNDREDS OF MILLION OF DOLLARS WITH HARDLY ANY RETURNS APART FROM ASTROUNAST SWIMING IN ZERO GRAVITY MONEY MUCH BETTER SPENT HERE ON TERRAFERMA OF THE REAL WORLD.
July 18th, 2008 at 1:12 am
Ugh. Am I the only one who skips straight over anything in all caps? Painful to try to read…
Regarding the article, it brings up an idea I've thought about many times myself, but doesn't really add anything to my internal monologue. I would find it most interesting and informative if the author (or someone) could crunch some hard numbers and find out if it's really feasible (see: decent radiation shielding, propellant required, etc.) and what it would cost.
My impression, despite what others have said above, is that it wouldn't take nearly as much propellant to get it to the moon as they seem to indicate. Not least because you don't have to hit escape velocity to be captured by the moon, and you don't have to fly straight there – just alter your orbit by increments until you're captured by lunar gravity.
I can't speak as to the stability of lunar orbit though. Why are there no stable orbits? Is there some paper or article on this I can read?
July 18th, 2008 at 2:39 am
Brilliant. So simple I'm surprised no one has thought of it or mentioned it before. Sure it will need radiation shielding, loads of fuel and probably a whole host of other things that the detractors above have failed to list. But good grief people, humans raise themselves when there are difficulties to overcome. You Americans know this better than most of us. Look how you opened up the interior of your country. Rivers? Ford 'em! Mountains? Blast 'em! Don't be put off a fantastic idea by what appear to be big problems.
Paul.
July 18th, 2008 at 3:03 am
I doubt the ISS' structure could bear any major acceleration. Which means you were stuck with ion drives and it would take quite some time to get around.
If stuffed full, how long can ISS go without resupply? We'd have to be sending a steady stream of Progress & ATV to The Moon And Beyond.
July 18th, 2008 at 3:18 am
Well, the idea is a good start-up. But think so fragile is the ISS to have an accident in the middle of the course to Mars. What about if the two toilets fails!!!
But the good point is about making a difference between the concepts of "spaceship" and "station".
We have just started to learn how to make Big Stations, whith problems, lot of parts, etc…
When Bigelow "Transhab" project start to put more and more modules in orbit, we'll have "standarized" stations that could be sent to Low Orbit, to Lagrange Points, to the Moon, to Mars, and Beyond.
No more incompatible parts.
No more money wasted to develop 1 specific module.
Make 100 inflatable and shielded modules, 100 H2 and O2 depots, 100 thrusters and you'll have the power to explore and live in middle Solar System
Of course, the politicans will want to make an "specific spaceship to go to mars" and spent lot of our money, but that's another story…
July 18th, 2008 at 3:52 am
The Station could be put on a Luna cycling orbit to provide a transit habitat and then serviced by Zond-class Soyuz flights. It would then periodically approach the Moon and allow teleoperation of semi-autonomous vehicles on the surface, and eventually provide transfer for manned surface missions.
July 18th, 2008 at 4:08 am
The incremental orbit increase to the Moon (suggested by another poster) sounds doable with minimal fuel use. Shielding would still have to be thicker in at least one part of the station for the occasional solaf flare. The immediate problem with going further than that (IMHO) is debris and micrometeors. That stuff is easily tracked now with ground based radar. The ISS would be a big target out passed the moon. I would guess it would look like swiss cheese by the time it got to Mars. Bring a lot of solar panels and patch kits.
July 18th, 2008 at 4:13 am
I like the idea. It sounds simple and practical. Poisonous to politicians though.
July 18th, 2008 at 4:14 am
I was never a huge fan of the ISS to begin with. I guess it served some purpose in the study of human physiology in space but, beyond that, I haven't seen much good come from it. I suppose I was hoping that the station would be used to investigate areas of manufacturing or chemical engineering that would attract commercial interests. If we really want a thriving space program, we need to get more than just the general public and a few telecommunications companies involved. I know there have been a lot of spinoffs from the aerospace industry that have found their way into the private sector. What I'm talking about is getting companies interested in doing business in space.
July 18th, 2008 at 5:37 am
ISS isn't exactly designed to do much more than it already does. However, thinking about what can be done with it does spring up some interesting ideas, and brings in some good non-expert participation.
I never understand those people who believe space programs from around the world are nothing but a huge waste of money. It's obvious they aren't the most self-educated, or self-motivated. If you really believe space programs are a huge waste, spend at least 30 minutes researching products which have been developed or greatly improved because of space programs. After you find out about several you take advantage of every day, you will wish your name was never added to your post.
Necessity is the mother of invention.
July 18th, 2008 at 6:10 am
Why not to land it on the Moon
? We need there a lot of tools and a base . Landing on Moon would be very hard but at least we have so much stuff already out . Landing on Moon is not so hard as it seems . Could be we accept a high G on landing with a lot of broken parts but at least we have something helping us there.
July 18th, 2008 at 6:15 am
Reply to Maugrum: ref instability of orbit around the Moon, see 'The Fate of Satellites of the Moon', Journal of the British Interplanetary Society, 27, 5, 385 (May 1974). Satellites of satellites are inherently unstable and this may even be why Mercury and Venus have no moons, being too close to the Sun for orbits around them to be stable. (Isaac Asimov, 'Just Mooning Around', in "Asimov on Astronomy", Macdonald & Jane's, 1974.) The sub-satellites left in lunar orbit by the Apollo astronauts lasted only 2-3 years.
But the original Space Station in the shuttle/Saturn V programme was to have been moved to lunar orbit when superseded by Space Base, so maybe it's doable, with ongoing station-keeping. Mind you, NASA was going to use the Nuclear Shuttle for the transfer…
July 18th, 2008 at 6:16 am
Actually it has been mentioned before – there was a brief discussion on the unmmanned spaceflight board.
The lack of shielding would be a major issue; also the size of the 'rocket' needed to move the whole station out of lower earth orbit… about twelve Saturn IVs.
It is a fun concept though, and perhaps taking a chunk of the station, harden it against radiation, and use the rest for bulk storage. Maybe 12 years of travel on solar powered Ion drives? It could keep us busy for a while.
July 18th, 2008 at 6:42 am
I also would like to see the numbers worked out to see if this is possible. Speculating about the use of the Space Station as the interplanetary vehicle was the final chapter in our book "Imminent Discovery" (see UniverseToday.com.,May 13th)- it's great to see that the interest in this is out there. Of course, at the very least, the Space Station should be where we bring Mars sample returns, since Mars almost definitely has life (as described in the book) and we don't want to risk back-contamination to Earth.
July 18th, 2008 at 6:58 am
Aodhhan: I hope the last part of your message wasn't directed at my post. No one appreciates more than I just how much we all benefit from the space program. The point I was trying to make was that I would like to see more private companies given a reason to get involved in the space program. As long as exploration and exploitation depend on NASA's budget, we'll just have to continue to accept politics as an inseparable part of the process. Replace politics with profit and see what happens. I don't approve of all of free enterprise's practices but I can't argue with their results.
July 18th, 2008 at 7:37 am
This does sound like a great idea, but why only focus on low-thrust missions to lunar (or Martian) orbit. Why not a low energy course to Earth's Lagrangian Points (esp. L4 or L5). This would be a great place to make all sorts of astronomical observations & still be close enough to earth for resupply missions to the station or have the station itself return to LEO on a similar low-energy, low thrust trajectory. A thought provoking idea to be sure.
July 18th, 2008 at 8:28 am
No Andy, not towards you.
You actually explain yourself . Others tend to just blast out against the ISS or whatever without any thought or explaination.
I don't mind people disagreeing or having a debate, but mindless shouting out irritates me a bit.
Sorry for any misunderstanding.
July 18th, 2008 at 8:34 am
Andy,
I actually agree with you on some points. I would love space to become profitable enough for private enterprise to be the major player.
Satellites are a good beginning, and it looks like short jaunts into LEO with private vehicles will be feasible within 10 years. Although at first this seems like a dreary waste, but it is these small private spacecraft which need to be perfected before space commerce (be it mining, vacation/sight-seeing, sports, etc) can really get moving.
July 18th, 2008 at 8:54 am
You know, this did cross my mind. But I was like, bah, if I could think of this, someone else certainly has. There must be a reason Nasa isn't going for it.
July 18th, 2008 at 8:55 am
I like the idea of landing the station in lots of little sparkly pieces, on the moon. Not sure what the point was but it was fun to picture the retro rockets guiding the one piece to the surface with the solar panels scattered hundreds of miles in every direction.
Inevitably, commerce HAS to be the driving force in space production. Is there anyone interested? Can we forge a partnership so we each get what we want? Nasa needs to make space attractive to more than meandering minds!
Could the space station orbit Mars as a way station for orbital transfer to landers and Mars-Earth transit ships? It could be there in time for the first human to Mars effort.
July 18th, 2008 at 9:37 am
This is a swell idea, but it seems to me the real advantage of using the ISS would be for something more long-term than a moon trip. That's what — 4 days transit, max? I like the idea of equipping ISS with an engine (Ion drive?) energetic enough to provide a little bit of GRAVITY for the complex, and then send it to Mars. My understanding is you accelerate halfway and declerate halfway, providing gravity for the whole trip. Compared to everything else, orienting modules so that all or most of them would have a "floor" relative to direction of travel seems pretty manageable. Sorry if somebody else has already mentioned this, I mostly just sort of skimmed the many responses. Obviously this is a popular subject.
July 18th, 2008 at 10:07 am
I like the idea of sending it to Mars for use as an out post where humans could stop off before they go to the surface.
Send the ISS to Mars unmanned if it takes too long to fly it there manned. Send it unmanned, fully stocked, so when we send a fast ship there, we'd be able to regroup at the ISS before going to the surface.
It would beat the hell out of burning up in Earth's atmosphere in just eight short years.
July 18th, 2008 at 10:47 am
I wonder if the I.S.S. could be placed in an Orbit with sufficient eccentricity that it would intercept the moon while benefiting from a gravitational Slingshot effect from the Earth? Since the Idea of Space exploration MUST be a long term goal of human kind, we have a while to work with here.
Unfortunately I just doubt the shelf life of the I.S.S. justifies the investment costs involved. Perhaps instead of letting it simply burn up like the Mir Station, once we are done with it we can set it drifting toward the moon.
It's hard saying, without knowing.
July 18th, 2008 at 11:32 am
Time to think OUT OF LEO FOLKS. I'm sure there must be other orbits that could be arranged. Say one that has an orbit that circumnavigates the earth and the moon. Or how about one that orbits the earth but has a high enough apogee (perigee?) that orbits earth and reaches out to the moon. Or verse-vicea.. Fill an ATV with fuel only and go on a tour d'Solar-system. We are talking space here. No friction. We need water. How about shielding crew quaters avec agua???. We've got enough heavy lift boost capability that is currently being used by idiotic spy satellites, crappy TV rebroadcast cruddelites – who needs 6 gazzillion channels of crud beamed down. Not me! C'mpn, lets use our rockets to EXPLORE SPACE. Do something exciting for a change, knock off our anal need to spy on each other and bore ourselves to death watching big Corporations and Gov'ts hose us for MORE MONEY.
rant over.
July 18th, 2008 at 12:05 pm
One step at a time folks. If the incident with the toilet taught us anything (and the air scrubber before it), we need to spend a few more years getting our feet wet "living in space" before we decide to send this thing flying off to the nearest planet.
July 18th, 2008 at 1:04 pm
I like the concept. When the experiments are done here, send it to Mars orbit. Would need to add "artificial gravity" , and a lot of shielding, if humans are to travel in it to Mars, otherwise automate it and park it in a high Martian orbit.
July 18th, 2008 at 3:09 pm
Dammit I thought of that last year, along with leaving the liquid fuel tanks from the shuttle in space to be retrofitted for use as modules in a space station.
Then I thought of another; why don't weuse the ISS to stage sections of the exploratory vehicles and fit them together in space the same way the ISS was constructed? And then launch from space where we can use the fuel purely to gain speed reather than using so much fuel to escape Earths gravity. I am aware that it takes fuel to get to the ISS but if all of the mission-only components were staged then we could get alot more speed out of our hardware.
July 18th, 2008 at 3:12 pm
Oh, I almost forgot. Try spending one years American military budget in space and see how far we get. Better that killing each other.
July 18th, 2008 at 8:06 pm
Slashdot covered this story three days ago, and the commenters there made mincemeat of the idea. Among the problems are:
* How do you accelerate the station without tearing it apart?
* How do you resupply it? It's difficult now. It will be more difficutt if it's at the moon, and damned near impossible if it's a Mars. We don't have continuous launch windows to Mars. For part of our orbits Mars is on the other side of the sun from Earth.
* If you send it to Mars, how do you get sufficient sunlight? The solar arrays are all right for Earth, but the sun's only half as strong at Mars. Adding new panels really isn't an option, because there aren't that many places to attach them.
* You need to protect more than just the crew from space radiation; the computers are vulnerable, too
Think of a canoe that you can paddle across the bay. Would you try to paddle it across Lake Superior? Or the Atlantic Ocean?
I have no idea if this comment system will let me format HTML, and I don't know If I can edit a comment after submitting. So here's the link to the Slashdot story in case the comment system mangles my hyperlink that the start of my comment:
http://science.slashdot.org/article.pl?sid=08/07/15/1852231
July 18th, 2008 at 8:32 pm
Uprooting a house and putting it on wheels does not make for a very good mobile home. Theres just too different a specification between the two, despite some similar functions.
This idea reads alot like "lets proclaim the ISS useless and hurl it deep into space where no one will remember what we were building". Mainly because we don't have the engines to make such a large transport, much less make one that can do a round trip to anywhere.
As it is the ISS is our only port destination in space. What sense is there in throwing it away?
July 18th, 2008 at 10:11 pm
Well, isn't the Orion program about nuclear propulsion!? If you don't mean that one, then maybe you should. Anyhow, nukes away on the SS, that is if it could withstand the stresses!
July 19th, 2008 at 12:05 am
"As it is the ISS is our only port destination in space. What sense is there in throwing it away?"
It's going to be thrown away *anyway* in 2016.
It would be impractical to launch the whole ISS to Mars, but why not strip it for parts?
Using the components from the ISS you could construct a vastly superior spaceship than one that was launched directly from the steep Earth gravity well. There are some designs that simply can't be launched direct from Earth to the Moon or Mars.
I say build a giant spaceship that spins to generate artificial gravity and takes advantage of designs that will work only in zero gravity and will never enter a gravity well. For landing a shuttle or lunar module type vehicle will descend to surfaces such as Moon, Mars, Earth.
July 19th, 2008 at 12:42 am
This is yet another idea inspired by the late Arthur C Clarke, In 2010, he describes a Chinese space station, that is suddenly given TJI – trans jovian injection escape velocity, to try to reach Juipiter before the Russian crew.
It does give you a sense of the scale required to reach mars…thinking about it, there is no way that the ISS could reach Mars in its current configuration. Though as proposed, this would be an ideal platform to acheive this. It requires a module attached for providing sheilding from cosmic rays, probably a module or two (that would also need sheilding) for the growth of a garden for sustaining the astros with greens.
Current orbital speed is 17500 MPH. It would possibly require boost to about 25000 MPH to be able to carry on to mars.
To do this you would have to find the center of gravity for the station, and probably retract the solar panels somehow.
Conceivable there is no reason to not use this vehicle to reach mars, but I beleive leave the moon to the ares configuration.
July 19th, 2008 at 12:57 am
Sorry Tyler
Artificial gravity is a no go, apparently, the gravity differential between your feet and your head is such that there would be major problems with motion sickness. The size of the station would have to be immense to overcome this. I know you mentioned giant, but you only have to look at the current world economy to see that it would be beyond the means of a lot of economies. Even the USA.
Don't forget the ISS is an International effort.
Thats why they never built a space station like the one in 2001.
And forget the USS Discovery as well, an internal centrifuge would cause major problems for implementation.
Unfortunately it would be zero gravity all the way. As far as I know…
July 19th, 2008 at 8:16 am
Slashdot covered this story a few days ago, and the commenters there made mincemeat of the idea. Among the problems are:
* How do you accelerate the station without tearing it apart?
* How do you resupply it? It's difficult now. It will be more difficult if it's at the moon, and damned near impossible if it's a Mars. We don't have continuous launch windows to Mars. For part of our orbits Mars is on the other side of the sun from Earth.
* If you send it to Mars, how do you get sufficient sunlight? The solar arrays are all right for Earth, but the sun's only half as strong at Mars. Adding new panels really isn't an option, because there aren't that many places to attach them.
* You need to protect more than just the crew from space radiation; the computers are vulnerable, too.
Think of a canoe that you can paddle across the bay. Would you try to paddle it across Lake Superior? Or the Atlantic Ocean?
Here's the link to the Slashdot story: http://science.slashdot.org/article.pl?sid=08/07/15/1852231
July 19th, 2008 at 11:03 am
The human being is not suited to space travel. Period. Robots, robotics, however you want to couch it, that is the way to go. Especially whilst exploring our own solar system Terraforming is needed on Mars (lifetimes of guesswork efforts), and that is about it for colonization probabilites with a "normal" life involved for any folks daring enough to undertake it.
Robotics. Robots. We can view it all from here and maybe spend a few dollars on restabilizing our own ecosphere. But, that's just my thoughts on the topic. Never a fan of the ISS either…
July 19th, 2008 at 11:35 am
I thought that the readers of this blog (as well as the author) were more well-informed than to buy into this idea. Here is a post written to the washington post which basically debunks this entire idea. Please read the whole thing before making any more misinformed comments:
As a space physicist and engineer, I praise Mr. Benson's enthusiasm for space exploration. However, I feel compelled to explain to him and the millions of Post readers he was allowed to mislead why his idea to send the International Space Station (ISS) on interplanetary jaunts is wholly unrealistic, and frankly, impossible.
For one thing, the shielding, wall thicknesses, and many other design aspects of the ISS were chosen to protect crews from the worst-case radiation environment known to exist throughout its present orbital environment. The ISS spends its entire time wholly within the protective cocoon of the Earth's magnetosphere, a complex electromagnetic structure generated within the Earth which also happens to protect the Earth from most forms of high energy cosmic rays and other ionizing particles. The ISS design is wholly unsuitable for long-duration jaunts outside this region and could not easily or practically be changed at this point to accommodate a different environment.
Secondly, Mr. Benson's proposal to simply connect engines to the ISS and launch it away from Earth and onto interplanetary trajectories completely ignores the fact that every source of propulsion he cites would impart accelerations, even small ones for certain scenarios, that the ISS structure, joints, and arrays simply cannot accommodate — the structure would simply exceed design tolerances under any source of thrust sufficient to launch it out of Earth orbit and on a transfer trajectory around the Sun to another Solar System body. Moreover, even the low-thrust ion engines Mr. Benson cites (actually, low "specific impulse," but that's another lesson…) would be unable to launch the ISS onto a transfer orbit to another solar system body, and certainly not on any reasonable timescale. It would be, perhaps, years before Mr. Benson's hypothetically-suitable ion engines could impart enough added velocity ("delta-V" to engineers) to move the ISS into an appreciably higher orbit, much less on a suitable trajectory to another planet in our Solar System. The ISS would require thousands of miles per hour of additional velocity to be placed onto such an orbit, regardless of the engine type used.
Thirdly, Mr. Benson's essay completely ignores the fundamental fact that even the most efficient transfer orbit between Earth and, say, Mars, requires at least 8-9 months each way, not to mention the time spent actually DOING anything once there. The ISS is simply unable to hold enough food, water, air, and other "consumables" for any sized crew for the duration of any mission of the type Mr. Benson has in mind. And "direct" trajectory missions that ignore the more efficient transfer trajectories require so much acceleration that the ISS would simply flex and buckle were an attempt made.
Forth, the amount of power the ISS solar arrays can generate is fundamentally tied to the solar energy received on their surfaces. Some of the interplanetary bodies Mr. Benson proposes visiting are at locations too far from the Sun for the arrays to generate enough power to operate systems on board. For example, the ISS solar arrays at Mars would receive only about half as much solar energy per square meter as they do at Earth. The ISS simply cannot accommodate hanging enough "extra" solar panels on its structure to make up for the difference, and wiring in new, additional power sources would require wholesale redesign of the ISS.
There are about a dozen other significant reasons why sending the ISS on interplanetary missions is completely unfeasible from a technical perspective, and which time an space prohibit me from addressing here.
Mr. Benson's claim that "…there are good answers to all these objections…" and his attempt at preemptive criticism of "skeptics" — as well his claim that NASA is not "particularly welcoming to outside ideas" — does not obviate the laws of physics, engineering limitations, much less the laws of astrodynamics and the hostile environment of our solar system.
And contrary to Mr. Benson's assertions, the cost of implementing his "good answers" to the objections (extra capsules, beefing up the ISS structure, adding new arrays or power sources, etc., etc…really WOULD cost far more than simply designing a purpose-built interplanetary spacecraft.
Needless to say, the Post and its readers would be well-served by having essays that make serious engineering proposals first vetted by someone with even a modicum of engineering knowledge before foisting them on an unsuspecting public.
July 19th, 2008 at 12:37 pm
Duncan – thanks for the references – very helpful!
Jason, that's a pretty good summary of the difficulties involved in taking the ISS to Mars (something I never remotely assumed was practical), and it seems like most or all of them apply to a lesser extent to sending it to the Moon as well. But it still seems like a waste to just let the station burn up in the atmosphere after all the time and effort expended in its construction!
Maybe it could be sold to Bigelow for use as one of their space hotels…
July 19th, 2008 at 10:27 pm
Okay, I've said this here before but this is a good time to say it again. The ISS should stay where it is and be converted into an orbital ship yard. Any ship large enough to carry crew, supplies, and fuel enough for touring the solar system or beyond would have to be built in space. The ISS is ideal for that. Add some more robotic arms and some storage capsules for sensitive materials and there you go. There is enough space junk and dead satellites in orbit already to provide some raw materials to start with. I think that the space shuttles should go up to stay too. Why throw away and waste something so useful? Even if they are not actually used they could still be dismantled in orbit and be rebuilt into the ship we are looking for.
July 19th, 2008 at 11:17 pm
It is not a problem of fuel or radiation shields or instable orbits. The problem is money. With enough money we can send ships to where we want to.
July 20th, 2008 at 6:44 am
If the ISS can't be made suitable for a journey to Mars, then how much will a purpose-built spaceship cost? My sense is all the problems raised by Jason should be addressed. I'd like to see the acceleration design limits for the space station, so we can calculate how long it would take to reach a velocity to transfer it to a lunar or Mars trajectory. Whether it's do-able or not is calculation, not opinion. How much electrical power would be needed – if the solar panels aren't sufficient, can more be added, or can nuclear batteries be added? As far as shielding, can some Bigelow-style inflatibles be filled with water and surround the key areas? It's hard to imagine humanity building a larger space vehicle anytime in the next 50 years – the scarcity of oil will keep the pressure on all economies. This is it – although we are spoiled by money for space, the space station was the result of that generosity. Either help make it work, or get used to seeing Mars through telescopes or rovers.
July 21st, 2008 at 9:42 am
In response to Jason, the "space physicist and engineer", you need to go take another lesson yourself on specific impulse. Ion drives are extremely *high* specific impulse, low thrust engines. Specific impulse basically boils down to an engine's efficiency, regarding the amount of fuel it takes to get a given mass of spacecraft to a given destination. Ion engines are extremely efficient, but impart extremely low thrust, while constantly releasing very little propellent at very high speed. You don't need to carry as much fuel, as with chemical rockets (high thrust, low efficiency) but it takes a long time to build up some speed (accelerate). If you're going a long ways through, that's OK. You have plenty of time to accelerate to the same speed you could achieve with chemical rockets, which burn intensely but shortly. The main thing you need for powering ion engines is elecrical power, which the ISS gets plenty of from its large solar arrays.
To accelerate out of low earth orbit, chemical rockets could be used to temporarily impart higher thrust.The ISS is clearly able to handle the thrust from the Shuttle, ATV, and Soyuz for reboosts, and this same amount of thrust could be used (say with a specially designed ATV-like propulsion module), using fairly long burn times, to get it out of LEO. From there, ion engines are perfectly fine. Since we know it could handle the chemical thrust used for orbital reboosts, it could absolutey handle the much lower thrusts of any ion engine.
That said however, I agree with Jason that after doing all these modifications, the cost would likely go way beyond just designing a purpose-built spacecraft. The ISS partners lack the testicular fortitude to do any of these modifications to the ISS within any reasonable timescale or budget. Just look at NASAs inane Ares I / Ares V design, when they could have used the Direct launcher design and been years, and billions of dollars ahead of where they are now.
July 21st, 2008 at 3:37 pm
Conflicts, corporate monopolies and mis-education / senseless entertainment are all far more profitable to stockholders than space exploration or human unity.
As it's been said it all boils down to money and how you make more of it. We could pretty much go anywhere if we had even just a quarter of what we spend yearly to kill each other, reinforce corporation's various strangleholds, sell useless junk on tv and generally act like retarded monkeys…
Hell even the Tobin Tax (0.1 -0.25% tax on speculative trade) would bring in at least 150 USD billions a year…That could be used to actually help people and draw them together using, for example, a global space exploration program…
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* World military expenditure in 2006 is estimated to have reached $1204 billion in current dollars;
* This represents a 3.5 per cent increase in real terms since 2005 and a 37 per cent increase over the 10-year period since 1997;
* The USA, responsible for about 80 per cent of the increase in 2005, is the principal determinant of the current world trend, and its military expenditure now accounts for almost half of the world total.
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World Ad Spending Growing Faster Than U.S. in 2008
According to a new study from GroupM, Advertising spending in US measured media is expected to increase almost 4% in 2008 compared with 2007, when spending was up about 3%. Worldwide spending is expected to go up 7% in 2008, after an anticipated 6% increase in 2007.
US advertising spending is expected increase 3.7%, to $168.6 billion, in 2008. Spending in 2007 is expected to come in at 2.8% higher than in 2006. Worldwide spending is expected to go up 6.8%, to some $479 billion
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* Currency speculators trade over $1.8 trillion dollars each day across borders. The market is huge, and volatile.
* Each trade would be taxed at 0.1 to 0.25 percent of volume (about 10 to 25 cents per hundred dollars)
* This would discourage short-term currency trades,about 90 percent speculative, but leave long-term productive investments intact.
* The currency market would thus shrink in volume, helping to restore national economic autonomy. Nations again could intervene effectively to protect their own currency from devaluation and financial crisis.
* Billions in revenue, estimated at $100 – $300 billion per year, would be generated.
* Revenue could go into earmarked trust funds to fund urgent international priorities.
IT'S ALL JUST A MATTER OF PEOPLE'S POWER + PRIORITIES. Technology was never the blocking factor for us humans…
July 22nd, 2008 at 12:04 pm
This reminds me of Contact (the book, not the movie) when all the mega-rich people are able to have their own private space stations. In the end, Hadden attaches boosters to his and reaches escape velocity from the solar system.
July 24th, 2008 at 4:29 pm
Ion propulsion could send the ISS to Mars.
Even if it would take a decade, it would be worth it. Send the ISS to Mars with a module to withstand the Corornal Mass Ejections, (for both humans and computers), and send it fully stocked with food and water for the Mars exploration crews.
Technology will advance within the next decade to make the naysayers of this look silly.
July 25th, 2008 at 7:37 pm
If the ISS is of no more use for NASA, Roskosmos and ESA, then the U.N. should decide to conserve her as an OBJECT OF incredible CULTURAL VALUE. She should become part of the cultural HERITAGE of species, of whole mankind.
I ask what the MIR would have become today, if she had been born under the same lucky star under which Hubble was launched only four years later put being still on duty after twentyfive years. But didn't the same categorical short term thinking threat the existence of HUbble a several times? Hubble is, NO DOUBT, of similar use for the understanding of where we come from and where our place in the universe is like the works of Kopernikus and Galileo Galilei. Imagine, the Pharaoh would have demolished the Pyramids after twenty years!
Today Russia is rolling in money due to increasing incomes from the energy business. The country is able to invest gigantic amounts in new weapons and even in space exploration.
Remember a view years ago when the orbital comlex MIR was still an artificial star to be observed with the naked eye on a clear night sky? The low budget was one of the main reasons to doom the MIR and sink her into the atmosphere, instead of lifting her to a saver orbit.
The question was either to serve the MIR or the ISS under the condition of restricted means. Nowadays, buffered by a blooming oil business, the Russians could afford to do both things at the same time. Times are changing.
And if the ISS is no longer used by NASA scientists, maybe the much bigger group of second rate scientists could use it for REAL SCIENCE, carried to the complex by Richard Branson's commercial space clippers weekly or monthly.
August 12th, 2008 at 6:06 am
Hmm, ok, so it's a complex and thorny issue and we're not going to resolve it here, but it is still fun to speculate.
I think having spent the time, effort and money in putting the ISS in orbit it seems very strange to allow her to burn up. Even if she can't set sail amongst the stars she should be maintained at the very least in LEO for staging for other support missions.
Given the massive area that LEO covers and the fact that the Shuttle can't reach Hubble AND ISS in the same mission I think we are in need of Multiple ISSs.
Each of the new ISSs should be built with the future in mind. Make it modular so each section can be mass produced on production lines like a car. Make them shielded so they can be put anywhere outside Mercury orbit and still work. Make them easy to bolt together so we can throw them up into orbit quickly. Make them strong so they can be shunted around the heavens without falling apart. And make them cheap so we can afford the odd loss on take-off.
Then Make lots of them. One Module and one solar array capable of sustaining two people for 6 months without re-supply. Put 6 stations in orbit around the globe, then start putting them at the 5 Earth Moon Lagrange points. L1 and L2 providing the perfect points from which to ferry missions to the lunar surface.
Then develop each station, expand it with more modules so that each one becomes a stellar ship-yard, building the ships that will take robots and humans out into the cosmos. Robotic missions are limited by the payload size of the launch vehicle, but if it was assembled in space at a station then you don't have to worry about size. L3, L4 and L5 could be good places to assemble deep-space probes and manned vehicles for martian missions as they could be launched towards earth giving them a slingshot.
But what of the ISS? We could use it as a technology test-bed or fill it with emergency supplies that could quickly be transferred to another station when needed. Whatever we do we must not waste what we have. Find uses for it as a whole or in bits and keep it flying as long as physically possible.
We took a step backward we we allowed Concorde to be grounded, we must not do the same in space. If we crash the ISS before we have other permanantly manned stations in orbit then we are not making progress.
I believe we possess all the resources and talents necessary. But the facts of the matter are that we have never made the national decisions or marshaled the national resources required for such leadership. We have never specified long-range goals on an urgent time schedule, or managed our resources and our time so as to insure their fulfillment.
This gives promise of some day providing a means for even more exciting and ambitious exploration of space, perhaps beyond the moon, perhaps to the very end of the solar system itself.
If we are to go only half way, or reduce our sights in the face of difficulty, in my judgment it would be better not to go at all.
In case the last three paragraphs sounded familiar they were taken from President John F. Kennedy's Special Message to the Congress on Urgent National Needs, May 25, 1961.
47 years later and we still find ourselves squabbling about what can be achieved and how much it will cost. We can achieve anything we put our mind too. Physical restraints, even the laws of physics, are overcome by technology and discovery. We re-write the rules as we go along and we must push ourselves to do these things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win. Kennedy said that too. Bright bloke!!!