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#1300
by
nacnud
on 19 Nov, 2017 12:23
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Well the trunk is thrown away each trip, and BEAM only cost $18 million and is nothing more than empty space. Given this is a commercial trip and assuming that the mission is possible with the extra weight the trade is whether this vehicle could be more profitable than just the Dragon 2.
The only way to do that is to add people to the trip each paying less than the current price but cumulatively the profit is more. There is also a time limit on this as once BFS is available it would be significantly cheaper.
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#1301
by
gongora
on 19 Nov, 2017 14:31
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This really is digressing. This thread is for the lunar flyby mission that SpaceX announced. Possible alternate architectures using conglomerations of habitats to fly varying amounts of people around the Moon/Mars probably belong in other threads.
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#1302
by
meekGee
on 19 Nov, 2017 16:43
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Why go to the expense of two dragons, take a BEAM instead. Add an extended duration pallet to the trunk too, if needed... Could make for some interesting stories.
Because then they'll be dependent on Bigelow, and I don't think they want that. Plus, Dragons are reusable.
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#1303
by
guckyfan
on 19 Nov, 2017 17:31
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I don't think SpaceX would spend major engineering capacity to expand Dragon capabilities when Dragon as it is can secure a valuable revenue stream until BFS becomes operational.
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#1304
by
Space Ghost 1962
on 19 Nov, 2017 19:02
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The art of pulling off this mission is in narrow/no scope creep.
The same FH configuration flown. The same Dragon 2 + consumables + deep space comm.
Nothing else added. Because then it leverages (and it in turn is leveraging) the CC program, both in proven new capabilities as well as scope of operation/mission profiles.
Remember that they're not taking Dragon past this point. NASA has no belly for it. So forget ambitions for Dragon, as long as there are no other "NASA class customers" asking for them. All serviceable market for Dragon is spoken for. BFS is next end of story. Just accept that. It'll be an amazing accomplishment just one free return mission.
Now to address "+ consumables + deep space comm". Propellant+ congingency is likely covered by existing launch abort capacity, ECLSS capacity is likely an addition/prove/qualification. Additional crew needs as well.
Deep space comm likely an addition under the docking adapter cap. Using a derivative of the MER/MSL HGA integrated into the avionics and software systems is what I'd start with. This is likely the "long pole".
FWIW, here's work on the
Iris cubesat DSN transponder at JPL. This a a low gain, low bandwidth application, but it gives one an example of scope of this activity.
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#1305
by
TrevorMonty
on 19 Nov, 2017 21:48
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Dragon doesn't have DV to enter and return from any lunar orbit. Flyby is all it is capable of.
To add extra DV would require service module, which needs between trunk and US. Can't be in trunk as is that is mass limited by LAS requirements.
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#1306
by
MATTBLAK
on 19 Nov, 2017 22:11
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Any 'propulsion pallet' in the trunk could be made ejectable at moment of abort by explosive bolts if need be. But that's only an idea and would require an additional, costly re-design. Which would be worth it in the context of other missions and further uses...
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#1307
by
Space Ghost 1962
on 20 Nov, 2017 00:45
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Stay on thread topic. "Crewed Circumlunar Mission". Goes around and comes back - free return.
Props are solely required for midcourse/entry corrections. There's already excess. Likewise, FH has excess delta V for this mission.
So lets say the vehicles are fixed, all the equipment (per my post above) is set no changes. What else might you do?
(Also lets assume DSN/Stargate/commercial supplement comm/tracking operations).
You're going to fly from 39A - the only pad with crew access. 39A/40 have been used to prep Dragon. West coast recovery and Hawthorne refit. Dragon mission outfitting local to pad. Every 3-6 months a CRS/CC mission, 2-6 slots for free return missions, so 6-10 annual mission rate for Dragon. 8-16 F9 reuse boosters, 2-6 FH core boosters, 6-10 F9US in total per year. That's a very healthy amount of operations for a HSF side of the business (nor counting recovery/reprocessing costs).
This would exceed Soyuz/Progress and only be surpassed by Shuttle in the past. Past a singular mission, reaching this kind of activity level would be a remarkable follow-on achievement. Cost of operations would drop significantly.
If all of this were to happen, well before EM1, you'd have a cost per seat of a lunar capable mission architecture in common use by NASA. The excess delta V in the capsule, LV, excess payload capacity, and vehicle flight rates/history ... would leave a lot of room for NASA/others to address mission planning shortfalls/contingencies with.
Anything that might result as HSF "follow on" for Dragon would come from that capability, refreshed by successive Dragon flights.
Even after Apollo flew, Gemini was constantly "resurrected". The cost basis alone made it too easy to do, even though it hadn't flown missions for a fair portion of a decade, unlike this case. A lot can happen in the in-determinant future.
But it's not SX or space cadet ideas that would arrive at such. Just the cold, hard realities of need. Like that of avoiding LOM/LOC.
add:
One other thing I forgot to add. It is possible for lunar and high C3 missions with certain orientations to fly an extremely lofted trajectory. This would be more difficult to track/navigate/guide than "normal", but it would allow vehicle recovery while imparting more delta-V to the payload, since its the downrange boost back and the horizontal velocity that increase stress on the booster recovery, not the vertical velocity as much.
So the vehicle doesn't rotate until after staging, you have certain concerns about trajectory and guidance, so this is far from an easy choice. It would mean longer entry burns for all three boosters, higher vertical decelleration/heating. But net/net more propellant into a delta-v into a highly elliptical orbit that would have to coincide with the TLI burn's ascending/descending node opposite the planet from launch. (And, if it were done from a higher latitiude like at Vandenberg, one could gain an interesting "advantage" from the lunar trajectory. One could also as a side effect bring along a geosynch payload that could "rideshare" after separation.)
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#1308
by
guckyfan
on 20 Nov, 2017 05:44
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Dragon doesn't have DV to enter and return from any lunar orbit. Flyby is all it is capable of.
To add extra DV would require service module, which needs between trunk and US. Can't be in trunk as is that is mass limited by LAS requirements.
Is this really true? Sure it can not reach LLO. But the available delta-v without powered landing, should be enough to reach a DRO orbit.
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#1309
by
envy887
on 20 Nov, 2017 13:02
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Dragon doesn't have DV to enter and return from any lunar orbit. Flyby is all it is capable of.
Very high lunar orbits only require about 300 m/s to enter and leave, and L2 NRHOs require about 650 to 700 m/s to enter and leave with a lunar flyby. Both are likely within reach of a stock D2, although cargo mass, flight time, and orbit utility and stability may vary.
DROs tend to be about 1200 to 1400 m/s to enter and leave, so only Orion can reach and return from those without upgrades.
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140003573.pdf
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#1310
by
HMXHMX
on 11 Dec, 2017 17:47
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#1311
by
flyright
on 11 Dec, 2017 20:11
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#1312
by
Phil Stooke
on 11 Dec, 2017 20:14
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There is no mention in the text, but the picture heading the article includes a SpaceX logo. But that's Space Adventures transferring its affections, not the customers. Still, it might move in that direction. Supposedly there are quite a few people interested in the SpaceX flights.
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#1313
by
Darkseraph
on 11 Dec, 2017 20:19
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Speculating on who bought the tickets, it could be someone who has already been a space tourist like Anousheh Ansari or Dennis Tito.
Since it has now come out that Ansari was one of the ticket holders for the Space Adventures/Russian circumlunar flight which appears to have fallen through, perhaps she is booked for SpaceX circumlunar voyage.
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#1314
by
flyright
on 11 Dec, 2017 20:26
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I did a doubletake on the picture heading the article (also including the Soyuz vehicle in the picture) because I thought that was the SpaceX logo, but believe it is actually the Space Adventures logo.
It does sound like Ansari and McPike may be possible customers for SpaceX, but there's nothing in the article to that effect.
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#1315
by
Dave G
on 14 Dec, 2017 00:05
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Deep space comm likely an addition under the docking adapter cap.
Why not the trunk?
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#1316
by
nacnud
on 14 Dec, 2017 00:31
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Deep space comm likely an addition under the docking adapter cap.
Why not the trunk?
Perhaps they want to bring it back?
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#1317
by
deruch
on 14 Dec, 2017 04:53
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Deep space comm likely an addition under the docking adapter cap.
Why not the trunk?
Oh, and Dragon also already has a sensor bay with a hatch ... a boom and a HGA assembly also might be made to fit there as well.
Yeah, no need for a grapple fixture on a circumlunar trip. As long as they can get it all to fit without interfering with any of the star-trackers that I believe are also in there, that seems like a good potential location.
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#1318
by
Comga
on 15 Dec, 2017 04:45
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Deep space comm likely an addition under the docking adapter cap.
Why not the trunk?
Oh, and Dragon also already has a sensor bay with a hatch ... a boom and a HGA assembly also might be made to fit there as well.
Yeah, no need for a grapple fixture on a circumlunar trip. As long as they can get it all to fit without interfering with any of the star-trackers that I believe are also in there, that seems like a good potential location.
They also don’t need the two SpaceX lidar systems in there, but we are speculating on technical minutiae.
Someone here may be able to estimate the size of the antenna they need, given assumptions about the receiver dishes, an adequate data rate, and power considerations.
Or perhaps we can’t with so many options.
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#1319
by
StealthGhost
on 26 Jan, 2018 17:33
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With the Flacon Heavy maiden flight likely to occur within the next two weeks & Dragon V2 set to perform an unmanned test flight to the ISS later this year (likely in November or December) almost all the pieces for the SpaceX lunar tourism mission are starting to come together. I’m a huge SpaceX fan & hope to work for them someday so a lunar tourism mission would be a huge hail Mary for SpaceX. It’s been almost a year since the 2017 announcement for the lunar tourism mission & still no updates.
SpaceX still hasn't even told the public who the two would-be lunar tourists will be yet. So does anyone know anything about their first lunar tourism plans? All I know is it’s likely not going to occur untill 2019 or 2020 because Dragon V2 has been delayed by commercial crew again & from what I’ve read NASA wants at least 7 successful flights of Falcon 9 before they can consider launching crew on Dragon V2 atop a Falcon 9 which could cause further Dragon V2 delays.
