Translunar Dragon Flights?

Some of the commenters in my Dragon post brought up the possibility of using a Dragon for lunar flyby tourism flights. I think this is an intriguing idea. The Dragon is about the same diameter as the old Apollo CM (about 30cm narrower), but much more roomy. They are meant for short jaunts to the station, but if you traded out say half the seating, and used some of that weight for extra food and sleeping equipment (and a thicker heat shield), it might just work.

Here, let’s play with some numbers:

The Falcon IX has a payload capacity to a LEO of about 9300kg. However, this is probably to a 200km circular orbit launched out of Canaveral (a usual way of rating launch vehicles). That means that to a 400km ISS orbit, it may be as little as 7000kg or so, so I’ll guess that the Dragon is about that size. If you assume that the upper stage of the Falcon V/IX vehicles is about a 94% drymass ratio (similar to that of their Falcon I first stage), with a 2700m/s delta-V for GTO, and then see how much payload the various systems could loft into a TLI trajectory, you get about 5600-5700kg for Falcon 9-S5, or somewhere around 8400kg for the Falcon 9-S9 variant. If you drop the number of crew/passengers from 7 to 3 (which would be a lot less cramped for that long of a trip), could you shave off enough to launch it on an S5 instead of an S9? Maybe. If you could squeeze it into an F9-S5, and assume 1 crew and two passengers, they could probably offer a ticket for only $50M each, and that’s for a much simpler system than the one Space Adventures or CSI were proposing. If you had to go with the S9 option, you might need more like $60-75M per ticket to make enough money off of the deal.

Since SpaceX has already said that it only intends to field the S5 and S9 variants once they have at least one prepaid customer, it might be possible to launch instead on a Falcon 9 with no payload and just a CBM connector on it, and then launch a second Falcon 9 with a Dragon, and with something like the Canadarm Mini idea I just posted about, and berth the two together. Doing it that way would likely still get you a ticket under $60-75M each, and more importantly would be using what would by then be an off-the-shelf booster.

Any way you look at it, this is an intriguing alternative to the other translunar options that have been previously discussed. The biggest win is the fact that it would be done out of a US launch site with a US company, with no need to go to Russia for 6 months of training. There are a lot of details I glossed over, but I don’t think there’d be any showstoppers for doing a Dragon flight around the moon.

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Jonathan Goff

Jonathan Goff

President/CEO at Altius Space Machines
Jonathan Goff is a space technologist, inventor, and serial space entrepreneur who created the Selenian Boondocks blog. Jon was a co-founder of Masten Space Systems, and is the founder and CEO of Altius Space Machines, a space robotics startup in Broomfield, CO. His family includes his wife, Tiffany, and five boys: Jarom (deceased), Jonathan, James, Peter, and Andrew. Jon has a BS in Manufacturing Engineering (1999) and an MS in Mechanical Engineering (2007) from Brigham Young University, and served an LDS proselytizing mission in Olongapo, Philippines from 2000-2002.
Jonathan Goff

About Jonathan Goff

Jonathan Goff is a space technologist, inventor, and serial space entrepreneur who created the Selenian Boondocks blog. Jon was a co-founder of Masten Space Systems, and is the founder and CEO of Altius Space Machines, a space robotics startup in Broomfield, CO. His family includes his wife, Tiffany, and five boys: Jarom (deceased), Jonathan, James, Peter, and Andrew. Jon has a BS in Manufacturing Engineering (1999) and an MS in Mechanical Engineering (2007) from Brigham Young University, and served an LDS proselytizing mission in Olongapo, Philippines from 2000-2002.
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17 Responses to Translunar Dragon Flights?

  1. Anonymous says:

    What I don’t see is why you’d try to hack something this cramped, and that is designed survive a launch, into a touring vehicle, when bigelow will be providing something far better suited to the task. The dragon is suited for getting to the habitat, the habitat is suited for an extended stay in space. If Bigelow was pretty far away from flying hardware and the dragon was operational, that might be different, but it seems as though they’ll both arrive in comparable timeframes.

  2. Juan Suros says:

    anonymous-

    You’d need the dragon’s heat shield to brake back into low earth orbit anyway, but I like the idea of taking a Bigelow habitat along for elbow room. This would also allow the full seven person crew to go.

    Would an expedition that bought a dragon capsule, a Bigelow habitat sized for 2 crew + 5 passengers, some sort of booster to put it all in TLI, and dumped the habitat on the return cost less per ticket than 3 separate dragon expeditions?

  3. jv says:

    Why dump the bigelow module? Couldn’t you just reuse it? How feasible is to detach from the Dragon and areobrake to orbit?

  4. Juan Suros says:

    Bigelow inflatable habitats are designed to hold atmosphere at a livable temperature, absorb micrometeor impacts without leaking, and I believe they have integral bags that when filled with water will give the interior spaces some radiation shielding. They are not, so far as I know, designed for the thermal and stress loads of aerobraking.

    Some time ago on this blog there was a long discussion of how to get hardware to and from the moon that mentioned aerobraking a bit.

    I was then and remain a fan of multipass, low-heat aerobraking on the return from the moon. The problem was that it takes a long time and exposes the hardware to lots of radiation. Maybe an unmanned Bigelow habitat could survive such a scheme and make it back to low orbit in usable shape. I guess the question would be how much extra would it cost to try to get it back?

  5. Juan Suros says:

    Here’s a crazy idea for a translunar expedition:

    1) Launch two Falcon 9-S9 boosters with no cargo, delivering just under 50 tons of fueled booster to low orbit. Bolt one of Jon’s manipulator arms to one of them to moor them togather and refuel one from the other, using up the one you empty’s helium thrusters to stabilize the platform during fuel transfer.

    2) If that works, lift a Bigelow habitat to join the fueled booster and deploy it by remote.

    3) If that works, lift four Falcon 9 boosters with Dragon capsules, each holding 1 crew and 4 passengers to join the expedition in orbit.

    4) toss the empty upper stage, bolt everything else togather and accelerate the lot to TLI.

    5) When you get back, let the habitat burn up and use the Dragons to return to Earth.

    You can even lose a Dragon, abandon it, and get everyone back by packing in seven people to a Dragon.

    Cost per passenger is 18 million for transportation costs, plus 25% the cost of a dragon capsule and 7% the cost of the Bigelow habitat.

    Just to make a WAG, say a dragon capsule and a habitat each cost as much as their lift to orbit. This gives a cost per passenger of USD$27 million. Double the hardware costs, and ticket cost is USD$35 million.

    That’s still a lot less than today’s USD$100 million going rate for three guys in a Soyuz with no redundancy.

    I’m not sure about the mass of fuel you’d need in orbit, especially given the unknown mass of a habitat, but each additional F9-S9 tanker adds USD$5 million to the ticket price.

    Or you could forget the habitat and bolt the Dragons to the booster directly for a USD$30 million ticket price, and still be able to abandon one of them in a pinch.

  6. Neil H. says:

    Are there any cycling orbits between the Earth and the Moon? One could imaging keeping a Bigelow habitat in such an orbit, and then have the Dragon dock with it as it passes by Earth to load/unload passengers.

  7. Jon Goff says:

    Anonymous,
    What I don’t see is why you’d try to hack something this cramped, and that is designed survive a launch, into a touring vehicle, when bigelow will be providing something far better suited to the task.
    Well, while Bigelow has expressed interest in eventually doing versions of his inflatable modules that could serve as translunar vehicles, those are a long way out development wise. I’ll be impressed if he can get his first Nautilus station up and running before 2010. It’ll probably 2015 or later before they’ll likely be in a position to do some of the further out ideas like his Nautilus Moon Cruiser. If both Dragon and Nautilus actually make it into operations, I would expect Dragon to be flying for several years before Bigelow has a lunar flyby capable setup of his own. So there’s still some window of opportunity.

    ~Jon

  8. Jon Goff says:

    Juan,
    While I agree that taking a Bigelow module along for extra space would be a good way to go in the longer term, I think that there is something to be said for a round-the-moon system that requires no additional hardware that isn’t already being developed to service ISS. Bare minimum, if you include a Bigelow Module and a full Dragon load of people, you’re talking something like 6-8 launches. While that isn’t crazy at all in the medium term, in the near term that puts a really high hurdle on getting things going.

    When dealing with speculative markets, you want your ice-breaker mission to have as low of a development cost as possible. Once you’ve proven out the demand, you can gradually upgrade the package and cut back on the price to open the market up even bigger. But until you have both demonstrated the capability, and more importantly proven the market, getting money to do stuff just for cislunar tourism is going to be tough. IMO that’s why CSI and Space Adventures haven’t gotten any takers. $100M for the trip is a lot of money to start with, and they also have to develop hardware that would be specific to that mission. If Dragon on the right sized Falcon variant could deliver 3 people on a decent lunar fly-by trajectory without any additional modifications, they have a much lower hurdle to jump.

    ~Jon

  9. Jon Goff says:

    Neil,
    I think you’ve hit the nail on the head. Nautilus modules are heavy. On the order of 50-60klb fully loaded according to the guy I spoke with there at Bigelow when I went on the tour. Putting that into a trans lunar trajectory is going to require a serious amount of propulsion capacity. Not having to do that every single flight would be a very good thing. Not having to replace the building every flight would also be a good thing. If you can have your capsule launch a few hours early, get itself checked out in a low parking orbit, then do the rendezvous burn fast enough, then a stock Dragon would be adequate for the job on the right sized booster, since you’re only talking about a few hours between launch and docking. Then the rest of the flight is in relative luxury.

    The only scary thing with cislunar cyclers is that if you miss your rendezvous, your capsule has to be able to survive for up to 14 days, which would really suck. I guess if you’re in close to the right orbit, a rescue mission might be mountable, or if you build in enough of a margin for the transport that could work too….but the devil’s in those details.

    Definitely may be a way to go in the future. I can see a fleet of cyclers (maybe 2-4 of them) eventually growing to several modules big with rendezvous opportunities once a week, and dozens of people flying each opportunity. But in the near term, I think we’ll have to start out smaller scale. But I could be wrong.

    ~Jon

  10. Jon Goff says:

    JV, Juan,
    Neil has it right. If you’re going to fork out $200M+ for a Bigelow Module, you may as well put it in a cycler orbit and reuse it over and over and over again. The aerobraking only needs to be done by the Dragon capsule, which is better designed for it anyway.

    ~Jon

  11. jv says:

    Neil, jon,
    thank you, I brought up areobraking only because I didn’t know of the cycler orbit.
    Jon,
    While I agree that “start small” is reasonable proposition I don’t believe going with something as “simple and small” as Juan’s 6+1heavy launch is a better way to go than using cycler orbit from start (isn’t it similar to the proposal which came out of the VSE implementation comission? – 8-9 EELVs?). In worst case you write off the Bigelow’s Module which you would do anyway in that scenario.

    Also, you put in place a nice viable system which can easily expand as market demands without any further developmental expenses.

  12. ShimaKatase says:

    Basic Bigelow lunar cycler habitat plus boost stage on a single Falcon-BFR launch? Subsequent F9/BFR launches can bolt on additional hardware as required, more habitat modules, bulk water + PV system to crack it for fuel on demand, reusable lunar orbit & descent vehicles…

  13. KaseiSol says:

    On a side tangent, We (MarsDrive Consortium) have concluded a study that calls for the use of MLLVs, possibly the SpaceX Falcon9-S9, to fill in for the mythical Heavy Lift Launch Vehicles that many in the Space and Mars advocacy circles deem necessary for manned Mars missions.

    Our mission profile, “Reach Mars for Less” can be viewed and downloaded at http://www.marsdrive.com/drm

  14. Jon Goff says:

    Regan,
    Commenting on the Mars for Less idea was actually one of the next things in my blog queue.
    ~Jon

  15. Mike Puckett says:

    An inflatible orbital module need not be a whole nautilus.

    Something to add 500 or 600 cubic feet would do the trick. Basically an inflatible Soyuz orbital module on steroids.

  16. Anonymous says:

    A Dragon on a Luna fly-by has no need to dock with anything, leave off the CBM and save alot of weight, perhaps enough for F9S5 launch?

    nacnud

  17. basementnerd says:

    In my opinion, I don’t think the Dragon is capable enough. I’d rather have them design a totally new lunar module in 5-10 years that could actually land on the surface.

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