I think that President Obama’s vision for NASA holds a great deal of promise. However, I seem to be in the minority – with people from Senators with NASA-associated districts to Stephen Colbert to Jesus Diaz on Gizmodo talking about the “end” of the human space program. I often wonder why they don’t see what I see. Obama has both increased the NASA budget and explicitly stated that he wants more astronauts flying in the coming decade than ever before, so he clearly is not trying to “cancel the human spaceflight program.” Given that, it seems straightforward to me that the NASA centers will still need to train astronauts, build vehicles, and conduct mission operations; NASA vehicles will still push the boundaries of capability, and NASA astronauts will explore the Solar System beyond Earth space. The only difference is just that astronauts won’t get to those new vehicles atop Ares launchers, but rather perched on something like the Falcon 9 – which is much, much closer to operation – and our targets are more ambitious. So why the enormous gap in opinion among space exploration proponents? And what might NASA administrator Charlie Bolden do to consolidate support?
I think the problem is that, without a NASA launch vehicle, critics have a hard time envisioning how the new generation of NASA astronauts will get around and what they will do. There won’t be any dramatic Space Shuttle or Saturn V launches – instead, the astronauts will be…”taxiing.” And they will taxi up to…what, exactly?
President Obama wants humans to leave the Earth-Moon system by 2025, get to Mars orbit by 2030, and develop the capability to live and work in space indefinitely. Here’s where Administrator Bolden could step in. NASA systems engineers and artists could crank away and produce concept studies to suggest a new fleet of NASA crewed vehicles. By starting right in on the design of new vehicle concepts, and setting explicit deadlines for their launch and operation, the new NASA vision could become more clear and exciting. The public will start to see what I see – a NASA program that develops dedicated space exploration vehicles, which carry astronauts for months at a time on journeys to deep space, asteroids, and other planets. Clearly, that is no end of the human spaceflight program. It’s the next step.
Below the break, I’ll outline such a possible concept vehicle fleet.
(DISCLAIMER: these vehicles are speculative concepts only. For now.)
With the freedom to just buy commercial crew taxi services, I imagine NASA developing a fleet of exploration vehicles designed to operate entirely in the space environment. And because space presents so many different challenges, these vehicles will be very application-specific. That is, there would be one vehicle for carrying astronauts around in the vacuum of space, one vehicle for landing on asteroids, one vehicle for landing on the Moon if we so choose, one vehicle for landing on Mars, et cetera. This would be a very new way for NASA to operate – take the examples of the Apollo Command Module, Space Shuttle, and Orion CEV, each of which must meet the challenges of launch, space operations, and re-entry. However, it’s not entirely unprecedented for NASA: the Apollo Lunar Module fits nicely into this paradigm.
Meet the first vehicle of my fleet, the mainstay workhorse for space operations, the Crew Operations Vehicle.
The COV would be about the size of the Hubble Telescope or an ISS module, it would be launched into space on something like an Atlas V HLV, Arianne 5, or Falcon 9 Heavy, and it would be built to stay in space and in operation for 5-10 years. It would support a crew of about 4 astronauts for several weeks to (perhaps) a few months of in-space operations. It would not be capable of reentering the Earth’s atmosphere, nor would astronauts be inside the vehicle during launch. They would come up to the COV, and down from the COV, in a Dragon taxi (or something similar).
Picture the COV as a Space Shuttle without the main engines, heat shield, cargo bay, or airplane shape. It would retain such features as maneuvering engines, robot arm, air lock with space suits, and ISS docking adapter, allowing it to become a sort of all-purpose assembly vehicle for larger spacecraft as well as astronauts’ main way of getting from place to place in space. On its own, a COV could conduct science missions, grapple with satellites, help modify or repair the International Space Station, and allow astronauts to practice the techniques they will need for exploration further afield than low Earth orbit. The compatibility with ISS is especially important because, with the station lifetime now extended to 2020 “and beyond,” it can potentially become the staging area for lunar, asteroid, and Mars missions.
The main engine on a COV would be at least the scale of the engine on an Apollo CSM, but ideally would be more powerful. If the VASIMR engine lives up to expectations in its upcoming shakedown on the International Space Station, then that might be a good candidate, as it would let the COV break Earth orbit. The COV engine would get its propellant from replenishable or replaceable containers, so that it can refuel in space. Like the Orion CEV, the COV would get its electrical power from solar cells; however, it would also have fittings for radioisotope thermoelectric generators (RTG’s), which are one of the few options for efficiently powering spacecraft beyond the orbit of Mars.
The COV, however, is not designed to support a crew on months-long missions. For that, we’ll add what I dub the Deep Space Habitation Module.
The new technologies developed under President Obama’s new NASA paradigm will really come into play here. Administrator Bolden, in his speech rolling out the new NASA budget, specifically asked for centrifuges to give crews artificial gravity and inflatable structures to give crews more living space, and that’s what I bank on here. After launch by a heavy-lift rocket, the DSHM would deploy and inflate to many times its size. A COV would then dock to the module, and the composite COV/DSHM vehicle would be able to support a crew of about 6 for many months – on a roundtrip journey to a distant asteroid, or to Mars orbit and back, for instance. For longer missions, NASA might even string together several DSHM’s, adding crew capacity and supplies to extend mission lifetime.
I suggest here an inflatable dual-layer construction, with an envelope of water between the inner and outer shells. This water layer would act as radiation shielding for the crew inside, and might even be integrated into the DSHM’s life-support and filtration systems. Obviously, extensive studies would need to be done to determine the best way to effectively shield astronauts on long missions from radiation. Water is a pretty good absorber, but perhaps this isn’t the best idea. Maybe it would have to be a solution of some kind, or be laced with polymers that have radiation-shielding properties, or maybe the intershell space could be filled with some kind of exotic foam. As I said before, this is where NASA could get new technologies going!
I have also placed a centrifuge chamber in the DSHM, so that astronauts can get in some time exercising in pseudogravity. (That’s supposed to be an astronaut doing crunches in the drawing!) That innovation would really allow for long-duration missions. Perhaps, if the DSHM is big enough and robust enough, the entire module could even be spun up to give the crew fractional g‘s in which to conduct their work.
With asteroids as an exploration target, we will need a way to “land” on small bodies and get astronauts outside their spacecraft. So, as the next vehicle in the fleet, I offer the Small Body Exploration Vehicle.
This vehicle is a direct descendant of the Apollo Lunar Module, but adapted to asteroid exploration. It would be capable of landing on, moving around on, and lifting off from asteroids. Since asteroid gravity fields are very small, the vehicle’s ascent engine (not shown) need not be very large, and it need not be subject to as stringent a mass restriction as the LM. So, the crew cabin might be only slightly smaller than the COV.
I have given the SBEV concept eight landing legs instead of the LM’s four. Each of these legs is a long truss, capped by a robotic, gimbal-mounted climbing piton. When the SBEV legs make contact with an asteroid, the robotic pitons would grapple onto the surface to anchor the legs. The gimbals then allow the SBEV to swing its body around those anchors, so that the next set of legs makes contact and can grapple. By repeating this process, the SBEV can “roll” itself along an asteroid surface. This process should be relatively straightforward, since asteroid gravity fields are small. The astronauts will remain largely in microgravity the entire time; they wouldn’t really feel like they’re rolling around as this happens.
I have also given the SBEV a suitport like those on the Chariot Lunar Electric Rover Concept. Rather than going out an airlock in suits, astronauts climb into the suit from the rear and then detach the suit from the outside of the spacecraft. This saves time, effort, and greatly reduces air loss. Once in a suit, astronauts can clamber over the SBEV surface, along handholds, to the landing legs and then down to the asteroid surface.
With those three vehicles, NASA could launch a weeks-long journey to one of the Earth-Moon Lagrange points, a months-long mission to an asteroid, even a many-months-long trip to fly by Mars and back or stage a landing on Phobos. The vehicles will all remain in space, ready for the astronaut crews who come up from Earth and return home aboard Dragon capsules. Here’s where the great paradigm shift of the “Flexible Path” could come in, too: If NASA decides to go back to the Moon, then all they have to do is build a Lunar Module mark II to couple with a COV. If NASA decides to put people down on Mars, then they build a Mars Descent Vehicle. If NASA decides to “land” a crewed, balloon-supported vehicle in Jupiter’s atmosphere, then they build a Jupiter Descent and Suspension Vehicle.
In this manner, NASA can start to build a deep-space exploration infrastructure, and that’s what I’m excited about!
Imagine ten or fifteen years from now, when NASA has a fleet of several COV’s in orbit, along with a few DSHM’s, a couple SBEV’s, and some fuel depots where the COV’s can replenish their propellant tanks. NASA could, at that point, actually have more than one active mission at a time. While the COV Columbia is on its shakedown cruise around the far side of the Moon, COV Challenger and a SBEV could be well on their way to an asteroid rendezvous. New space achievements would rack up rapidly, every couple months or faster. Astronauts from all over the inner Solar System – Earth orbit, Lunar orbit, Lagrange points, asteroids, Mars, going further than any human being has gone before, with more astronauts in space than ever before, could be sending back blogs and videos and tweets on an accelerating basis.
And, of course, these vehicles have to be designed somewhere. Perhaps Goddard Space Flight Center and the Jet Propulsion Laboratory. They have to be built somewhere. That would likely be Marshall Space Flight Center. They have to be launched – aboard a commercial vehicle, yes, but that is still going to happen on the Space Coast of Florida. And the missions will still be operated out of Johnson Space Center, where the astronauts trained in COV and SBEV mock-ups. The loss of jobs from Shuttle and Constellation ending plus the gain of jobs to support the new manned space programs ought to be a wash.
That’s the new NASA that I see. So far as I can tell, it’s perfectly consistent with the goals and strategies outlined by President Obama and Administrator Bolden. Now, if we could see some actual, concrete concepts for the new NASA fleet from inside the agency, I think the critics of the new NASA paradigm will have much less reason for anxiety.
Uhhh..mmm. I guess I read too much Robert Heinlein as a kid or something, but I’ve always wanted to see human beings living on other planets or moons or asteroids and maybe even flying between the stars, a la Star Trek. I don’t think I’m unique.
The Apollo program looked like a step in that direction, but Apollo got killed off. What we’ve had since, for pushing 40 years, is a space shuttle program and a space station. A small space station, all things considered, not doing much. We were learning to keep people alive in space, it could be said. With air brought from earth, with water brought from earth, with food brought from earth, with toilet paper brought from earth… Yeah, we were keeping people alive, but only in the sense that we keep convicts alive in jail cells — people on the ISS clearly aren’t living the sort of lives they might have in Kansas, or — one hopes! — someday in Luna City.
Well, okay. One waits, the shuttles were getting old, and change must come. And so it did in 2004 when President Bush announced a new space policy, with a return to the moon, with long duration stays and learning how to use the moon’s resources for eventual trips to Mars. All of which seemed to point to picking up the old spacefaring dream near where it had fallen in 1972.
Then, of course, the “new space policy” became ESAS which became Mike Griffin’s Constellation program which became “Apollo on steroids” and the necessary funding never came along and one could see the whole idea turn to shit.
Well, shucks. So the space shuttles are still on the way out, and Constellation looks headed for the chop. So what’s next? one wonders. Small “commercial” vehicles to send supplies and crew from earth to ISS? Yeah, that seems reasonable. Granted the happy predictions of profit ahead for new “New Space” entrepeneurs look a bit dubious, given Lockheed and Boeing’s experience with EELVs, but…
What else? We’re going to save NASA money by hiring out transportation to ISS. We’re going to kill the unaffordable Constellation program and replace it with ….
Blink! A flight around a near-earth passing asteroid in just another 15 years! A flight around Mars in just 25 years! with a landing — sometime — to give us a nice old fashioned Apollo-style Flag & Footsteps finish.
Obama’s new space pollicy does not give us People Living In Space, or even point in that direction. In other words, just like the shuttle and ISS, it really doesn’t lead to much. It’s actually possible to dislike that policy for just that reason.
I definitely don’t think you’re unique, Mike. I, too, would love to see humans flying to other moons, planets, and stars. It’s too bad that none of that can happen right away, and we’ve got to have all these intermediate steps in between. Getting to other stars, in particular, has got to require fundamentally new technologies.
In my mind, this new program is actually a step in that direction. It puts us near other planets and bodies, and it puts us in space away from the Earth for extended periods of time. It stresses developing all the technologies we’d need to realize a Heinlein-esque vision, instead of scrambling to an arbitrary goal with a repetition of proven technologies. I disagree that the new space policy doesn’t even point in the direction of living in space; after all, that is specifically the idea. Obama’s April space policy speech even finished up with the statement that “our goal is the capacity for people to work and learn and operate and live safely beyond the Earth for extended periods of time, ultimately in ways that are more sustainable and even indefinite.”
I’d like to ask you, Mike, what you would do differently from President Obama, given the (painful!) constraint that an unlimited NASA budget is politically unviable. You’ve seen my thoughts on the new policy, and you’ve seen my ideas on how a new program could take shape. What are yours?
Used to be a fellow named Harry Shipman — still is, he’s a physics prof at UDelaware — and he wrote a book called HUMANS IN SPACE: 21st CENTURY FRONTIERS. Shipman made the point that figuring our a role for humans in the solar system relies on the answers to two questions: (1) Can human live elsewhere than earth? I.e., can they produce food and water and air maintain themselves, can they reproduce and lead healthy lives in isolation from earth? (2) Is industrialization possible in space? Can we mine for minerals, etc? Can we refine ores and process material in factories to make products which might use in space or be exported to earth?
If both answers are Yes (he gave this about a 40% chance), he thought humans might colonize the solar system. If only the first question got a yes, we’d be limited to visiting moons and other planets for short periods (Shipman called this “tourism”). If the second, unmanned mines for gems or He-3 or platinum-group-metals might be profitable. If both answers were No, humans would probably be limited to short stays in space with lengthier scientific observations by unmanned spacecraft.
Shipman’s book came out in 1989. Thirty two years had passed since Sputnik by then, and no one could answer his two questions. No one, in fact, was trying to answer his questions.
Another twenty years has passed. The “Space Age” is now 53 years old and no one can answer Shipman’s questions, and no
one is actually trying to answer them (well, no one has funding and an approved research program which might lead to answers). With President Obama’s program, we willl still not be able to answer these questions twenty five years from now.
I’d concentrate on answering those questions.
Sounds reasonable. How do you think we should go about answering those questions, then?
It strikes me that sending people out beyond the Moon’s orbit, and taking a close look at scientifically interesting or potentially exploitable asteroids, are experimental ways of answering them. Given the difficulties and unknowns in finding those answers theoretically, that might make President Obama’s program the best shot we have at answering Shipman’s questions.
Since the cancellation of Constellation, I’ve been stumbling around the internet, trying to make heads or tails of the current controversy. Your blog has been an oasis for me — it’s really the only game in town when it comes to optimistic, creative, and informed thinking on manned space exploration (if there are other sites with a similar viewpoint, I’d love to hear about them).
My instinct is to feel excited about Obama’s new space initiative. So excited that I’ve come to its passionate defense several times, at a cost of many hours of fruitless argument. Having interacted quite a bit with the program’s opponents, it seems to me there are two major problems facing Obama and Bolden.
First, the plan is vague. This early in the game, it really has no choice but to be vague. I can empathize with the protestations of soon-to-be-unemployed NASA engineers who feel that the decision to cancel Constellation should not have been made until we had a more concrete sense of what would replace it. I can also see it from Obama’s perspective — that Constellation was a money-gusher that needed to be plugged, and that no matter what we ended up replacing it with, there was no doubt of Constellation’s non-sustainability. That vagueness, however, has turned the program into a giant Rorschach blot, in which no two people see exactly the same thing.
You and I see NASA’s first real steps into deep space — finally an inspiring, unexplored frontier after fifty years of screwing around in LEO (unmanned achievements notwithstanding). I love the schematics you provided in this post — I hadn’t let myself dream in detail about the possibilities, and I got a little giddy thinking about the nuts-and-bolts reality of such a mission.
But that leads to the second problem — many people, especially those who are opposed to Obama politically, see something completely different when they look at that inkblot. Some people are convinced that no matter what Obama or Bolden says, underneath it all there’s some nefarious scheme to weaken and eventually destroy the United States. For these people, there isn’t much that can be done. I recently listened to Zubrin and Bloom on Coast to Coast AM (it’s on Youtube), and they absolutely hate Obama’s new program because they’re convinced that John Holdren (director of Obama’s Office of Science and Technology Policy) is hellbent on neutering NASA because — and this is where is stops making sense to me — he’s an anti-population-growth eco-extremist of some kind.
But for the rest of the doubters, we need some specificity, and we need it quickly. NASA needs to be able to say “the COV and DSHM will look like this, and here’s where they’ll go.” Basically, what you just did, but backed up with money, commitment, and, most importantly, fancy animations. We all need something to hang our hat on here, and the debate will just keep heating up until that happens.
In his speech, Obama wasn’t very convincing in his remarks about that eventual Mars landing (“eventual” isn’t an encouraging word when it comes to NASA). Regardless of whether he’s certain it can be done, he needs to make much clearer, right at the beginning of the next speech, that this is a Mars program. He should frame all these as Mars-precursor missions. Mars, Mars, Mars. So the next time someone gripes to me about Chinese astronauts on the moon, I can say “Mars.”
You’re doing great, Joseph! Keep it up!
Thanks, Nate! I think you and I are of similar minds on this – where I heard the new plans and pictured deep-space vehicles with science-fiction technologies conducting Gemini-style missions to lay the foundations for our journey into the wider Solar System, others just saw the end of the current, hamstrung vehicle programs and confused that with the end of US goals and visions for space exploration.
Glad I have been providing you with a bit of optimism about this!
I think for some reason you are chosing to ignore the issues. If the idea is to see whether people can live for long times in space, we need to have people in space (and bugs and mice and spiders and fish and wheat and tomatoes and marijuana plants and elm trees and everything else people are familiar with). For years, in different environments — orbiting the earth, sitting on the moon, sitting on Mars, floating in the clouds of Venus, etc. We should be studying pregnancies in space, we should be studying death from old age in space.
With real people.
We ought to try devising equipment to let people on the moon perform mining surveys on their own hook; we ought be testing machinery and methods for mining the moon; we ought to be building factories or tools for extracting air and water and useful metals from moon rock. We should be trying to grow food in lunar soil or with hydroponics; we should be building recycling facilities to get maximum use of lunar water. We probably ought to be doing this on a a space station as well as on the Moon and eventually we should be doing this on Mars.
We should be studying near-earth passing asteroids to examine their composition; we should be testing technology to bust up smaller ones and capture pieces for raw material. We should be conducting mineral surveys of Mercury, and dispatching spacecraft to survey the “ordinary” asteroids in the Belt.
We should be building a “lunar shack” to house 2-6 astronauts on the Moon; we should be testing to see if solar flares and cosmic rays make surface dwelling impractical; we should be examining smaller craters to see if doming them with plastic sheeting could make them livable; we should be investigating the livability of natural and man-made lunar caverns. We should aim at creating a lunar settlement covering dozens of square miles, with fields and factories. We should be aiming at creating a colony which, in a pinch, could be self supporting. We should be creating a settlement which interacts economically with earth, for mutal benefit. All going well, we should be creating multiple settlements, growing steadily as immigrants from Earth arrive.
And so on.
So you don’t like these ideas. You think they look really expensive, when carefully considered. There’s too much talk of “testing” and “trying out” and not enough good academic computer modeling and sure-to-be-approved demos that will pass Congressional scrutiny. There’s an awful lot of risk and things that ought to be dragged out over decades, I seem to want done in years. (Yep!) I haven’t addressed international politics; I haven’t checked this for financial reality against the declining dollar and the expanding deficit; I haven’t probe the entrails of surveys to see if my fellow American voters could stomach such a use of their tax dollars; I haven’t hinted yet at the number of webbloggers and daily tweets and YouTube videos required to make this palatable to The Public.
Tough. I’ll leave that to The Next Generation.
Don’t get me wrong, Mike – I *LOVE* those ideas. I second every one of them!
The problem is how we get from here to there. We can’t just say, right now, “We’re going to start a mining base and monorail system on the Moon, an new nation in an O’Neill cylinder habitat in Earth orbit, a fully staffed research base on Mars complete with food court, asteroid mines throughout the main belt populated by scruffy, independent hardass miners, and an outpost below the ice crust of Europa. Poof!” and have it all happen immediately. (Boy, would I love that, though.) We have to start somewhere. We have to take the first steps.
The question, for me, becomes, “Taking the premises that human space exploration and colonization are desirable things, that space exploration and colonization must be very-long-term endeavors, and that the space program is subject to political, financial, and technological constraints, what is the fastest, most efficient way to push human lives and work sustainably out into the Solar System?”
President Obama’s plan looks, to me, to be the best policy I’ve seen to get us started along that path. In fact, everything I have read about it suggests that its objectives are to take a good stab at many of the items in your “we should…” list, above.
Your comments seem to oscillate between criticizing the post-Apollo space program for not having already given you all the space colonies you want, and criticizing Obama’s space program for not being a feasibility study. I don’t see how any space program could satisfy all your concerns, and I’m not quite sure exactly what your problem is with me. That, and your comments here seem to have little to do with the specific content of my original post….
I will try elaborate longer later, but now one idea so basic and so important struck my mind that I have to say it.
The prolonged time of unclear and non ambitious space program is because there is no competition. Since fallen Soviet union there is basically nobody to compete with, nobody with who you can race to accomplish impossible such as landing human on the moon. Soviets stopped racing shortly after Apollo landing, and that is the time when even NASA stopped to have big ambitions. It will sound bad but…
we need China or India to step up the space race and challenge NASA to accomplish impossible again.
That is for now, later I will try to write about how i see we can get people on moon (and beyond) in less than 10 years and what vehicles we can use… but I’m at work so later.
Lubos
I admire your ingenuity, but I’m inclined to quibble a tad with some of your spacecraft concepts. (I’m being disagreeable to show I’ve pondered your ideas BTW — please don’t view these remarks as pure negativism).
I don’t know that I’d hard-mount solar arrays to a spacecraft body, for example as you did on your first module. Keep them separate is my thought, so accidents (meteorites, Apollo XIII mishaps, etc.) don’t disable everything. Use flexible tubes between the arrays and spacecraft to carry fluids or electrical wiring; reel in the arrays or cut them free at the appropriate part of the mission.
For the Deep Space Hab Module, I’d go for something looking like a bicycle tire, say a 10 foot diameter tube forming a wheel maybe 100-150 feet in diameter. Psychology is the prime factor, I think — on a long voyage, people are going to want a little separation from each other now and then, so something that lets crew members zip up some interior walls and ignore other crew members seems worth doing.
Also, I’d spin that wheel so people sleeping against the back (“down”) wall would feel Martian or maybe earthly gravity.
And I probably wouldn’t use water as a radiation shield on the outside of the wheel. Remember, if you want to duplicate the shielding of earth’s atmosphere, you need a water column 34 feet high — that’s an insane amount of mass to carry, so I’d go for a layered shell, say three concentric plastic tubes with some gas and lots of loose aerojel as a spacing element (and hole-plugger). Maybe five concentric tubes, each barely thicker than cellophane. Things that shouldn’t rotate, like an observation deck and maybe a medical center and a solar storm refuge would go at the axis of the wheel.
Your Small Body Exploration Module definitely strikes me as overkill. Consider that an asteroid with a 40 mile radius is going to have a surface gravity of about 0.01 g — and that’s probably ten times the size of the first asteroids we get close to. You don’t need a whole separate seperate spacecraft to land and take off from something so small. I’d suggest something the size of a stock trash can would do the trick — just mount rockets on the outside and air bottles on the inside and let the astronaut stand inside wearing his spacesuit. Keep this unit very very simple, in other words; it doesn’t need smarts; it just needs a radio link to the astronauts’ main vehicle, which presumably has smarts to spare,
I’m guessing some constraints are going to apply, which I think you think won’t apply … I don’t think these or similar modules are going to be manufactured on earth, for example. I don’t think they’re going to be carefully designed with elaborate preliminary and critical and final reviews. I don’t think construction is going to depend on ultra precise tolerances and carefully machined structures made from specialty alloys. My money’s on sloppy but sturdy vehicles welded in vacuum, with software (and lots of little steam-puffing venier engines) making up for the lack of manufacturing elegance. They’ll be quickly built, cheaply run, and easily disassembled, and they’d have about as much charm as a 5 year old’s Erector kit.
Middling long run, like say 50 years, I wonder if anyone will be using spacecraft with a “fixed configuration”. My guess is spacecraft will morph from one shape to another. Launch a conical spacecraft from earth, have it turn cylindrical for the voyage to Mars, then extend long wings and land as an aircraft, switch back to a cone for launch, and finally land as a delta-winged aircraft on earth… Really, this might not even be particularly hard!
Thanks for the comments, Mike! I’d love to see the results if a couple engineers got together and workshopped something like these speculative concepts. Especially since I made my usual mistake of diving into the drawing and writing without crunching any numbers!
I’m all for modularity in spacecraft designs. I’d love to see our future spacecraft have not just modular solar arrays, but separate modules for hab compartments, laboratories, engines, life support systems, power systems, etc. I was thinking that there could be several versions of the DSHM, and the actual spacecraft that goes to Mars or Jupiter or whatever could be composed of four or five of them. If our centrifuge and deployable/inflatable technology gets up to it, then the bicycle-wheel configuration would certainly be a good idea.
I chose not to sketch a wheel-shaped spacecraft simply because I also wanted to draw the water-layer shielding idea, and a circumferential spacecraft would require much more water. I didn’t look up the 34 ft figure (thanks). But what if the water column was 15 feet, getting astronauts into airline pilot exposure range? What minimum thickness would be acceptable for, say, a 2-year mission? I also wonder if that water could be doped with something to enhance its shielding effectiveness, or if there might be some exotic composite (or other material) that the outer and inner shells could be made of to further reduce the water layer. (Of course, we’d have to compare that to a big, dumb layer of lead for completeness….) Maybe we could get the total mass into the range where launching an inflatable bicycle-wheel become feasible, even if the water has to come up on a separate launch.
I suppose my small body explorer would be best suited to the larger asteroids, the ones with surface gravity in the 0.01 – 0.1g order of magnitude range. For the really tiny bodies, what about a vehicle designed in analogy with one-man submersibles? These could sort of straddle the line between spacesuits and spacecraft. The astronaut, in shirtsleeves, would be inside a small cylindrical cabin with just enough room to scratch their nose. Life support would last on the order of a day. The spacecraft would have only small thrusters for mobility, and waldo arms for sample collection. It could even use virtual reality/augmented reality on the interior to make the astronaut feel “closer” to the body they are exploring, or perhaps give them the sense that they are floating free outside the confines of the craft.
Reconfigurable or morphing spacecraft would certainly help merge all these single-application vehicles into one. (This is actually related to my research!) The problem I have with combining everything into a single vehicle is that everything I know about reentry suggests that we’re never going to get away from needing a heat shield. Heat shields are, at least currently, generally heavy, which makes carrying them around during space operations more of a liability and limitation. That said, I imagine that the next generation of heat-shield composites could be much lighter than even the shuttle’s thermal protection system. Now if we can get some shape-memory heat-shield composites, you’re really on to something!