FH to the moon?

[Avron]

It'd still be a whole new vehicle development, but at least it'd have some commonality with Dragon.   

I played around with this a while back, have a look!

http://forum.nasaspaceflight.com/index.php?topic=30567.msg989644#msg989644

Try something different like an MCT .. maybe a mini version..  I for one don't think there will be much in common with Dragon. For your MCT or LCT .. look at a single engine for landing and return.  Then a Dragon to get back to Earth.

But the title of the thread is "FH" to the Moon, not MCT to the moon.  I'm sure some modified MCT could do it if it could do a Mars mission.  But I think the idea here is with FH, and derivatives of soon to be existing hardware in CrewDragon.

Thus the LCT..  launched I guess via FH.. or FH's  CrewDragon to the moon.. only if they laws of nature change. now if it was linked (docked) to a LCT it may work.. but not land. I would love to see a FH with Dragon do a freereturn. To the moon and back via FH., now that may work with "soon to be existing hardware"

[Dave G]

Thus the LCT.. 

For a Lunar Colonial Transporter to work, you would need someone who wants to colonize the Moon.  SpaceX has said several times they are not interested in this.  In fact, SpaceX has said colonizing the Moon would be harder than colonizing Mars, due to lack of atmosphere, relative lack of resources, and lower gravity.

In other words, SpaceX will not spend their own resources on lunar specific hardware.  They might use the Moon as a test for MCT, but that's about it.  If someone else develops new hardware specifically for a manned Moon mission, SpaceX has said they would be glad to launch it.

[AncientU]

FH should send a Dragon or DragonLab to EML-2, pause and take the money shot of Moon and Earth from 60,000 km beyond the moon.  A high velocity return and re-entry would prove access to a future deep space outpost at a 'reasonable' cost, should an asteroid (or whatever) show up there one day.

[TomH]

Okay then, how about the need for the U.S. to forge stronger ties with Pacific Rim allies?   Japan, Korea and Singapore would all like very much to be part of a manned mission to the moon.  If not the U.S., they will be drawn into the Chinese program.

Oh my! The Koreans and Chinese both hate and abhor Japan. Please do some research involving the historical relations of these nations.

[DaveJes1979]

Why is everyone assuming that we need a Dragon-sized spacecraft to put men on the moon?  That is an awfully large capsule.  You might be able to get there with a single Falcon Heavy if you start thinking more along the lines of a Gemini-sized two man capsule strapped to some hydrolox stages.  Sure, you can't stretch out your legs and you use a MAG to meet the call of nature, but if you land your habitat and rover ahead of time you can have a useful little mission with two launches that don't need to be timed and phased in concert.

[Ben the Space Brit]

You're just shifting the burden onto the precursor missions - how do you get the hab and the rover on the Moon? More importantly, where do they come from? Whilst we're at it, where do these hydrolox stages come from? And how do you get enough delta-v to return from the Moon to Earth?

I'm not saying it's undoable, what I'm saying is that there is a lot of expensive and time-consuming hardware development that is needed first. This is a fact that cannot be hand-waved away.

[KelvinZero]

Quoting the whole thing because it is a little way back..

I agree SpaceX isn't likely interested in a version of Dragon customized such that it is solely suited for lunar surface missions. I propose here by means of the attached diagram an "Extended Duration Mission Kit" which would be an add-on to Crewed Dragon. I make some assumptions about what Crewed Dragon will include different from Cargo Dragon, and those are shown in the diagram through use of various colors.

Starting with the basic Cargo Dragon in brown, I've added in pink features I hope to see in Crewed Dragon:
 + Electrical power provided by batteries
 + Thermal control provided by "capsule fin" radiators
 + NDS-compatible SpaceX docking system

The extended duration mission kit shown in blue includes:
 + SpaceX docking system electrical and propellant transfer
 + propellant storage tanks
 + photovoltaic electrical power generation

The propellant tanks in this mission kit would be sized to meet the demands of the mission type with the largest delta-v requirement. I here assume that to be lunar ascent.

Anyway, I hope the picture is worth at least some fraction of a thousand words. "Happy Christmas to all!"

Initially I couldnt imagine the Dragon being useful for the moon since the delta-v is so different, but then I remembered that the Dragon's propulsion system is meant to be sufficient for the LAS, an uncomfortably large g force, whereas the crew of the apollo lander stood up during landing.. Maybe the dragon engines are powerful enough if the fuel lasts.. but could such engines last to give you around 2km delta-v if the fuel was available?

Another thought re the picture  (missing from the quoted version).. Because of the weird side mounted nature of the dragon engines, could the additional fuel be in a trunk below the dragon? This would mean it could be there all the way from earth, and could be dropped during ascent from the moon. (big drawback, you couldn't use the dragon landing gear, which I guess may be sufficient for bearing the much greater weight of the ascent propellant if in lunar gravity.. on the other hand it occurs to me having your heat shield that close to the regolith with the thrust throwing stones around could be bad. Is this a lunar only dragon?)

[TrueBlueWitt]

Why is everyone assuming that we need a Dragon-sized spacecraft to put men on the moon?

You're right. We don't need that. We just can't afford to develop anything else.

Why not strip a Dragon to bare minimum..a separate lander. Strip heat shield.. parachutes.. Aero panels and super Draco's. Add back the bare minimum vacuum optimized super Draco's monted vertical(no cosine loss). Could add inflatable airlock. Add fuel in space where heat shield removed. Would the mass/fuel savings be enough to justify a separate dragon based disposable lander?

[guckyfan]

Why not strip a Dragon to bare minimum..a separate lander. Strip heat shield.. parachutes.. Aero panels and super Draco's. Add back the bare minimum vacuum optimized super Draco's monted vertical(no cosine loss). Could add inflatable airlock. Add fuel in space where heat shield removed. Would the mass/fuel savings be enough to justify a separate dragon based disposable lander?

Sounds good. And while they are at it they can change the shape of the pressure vessel also. That would be the easiest step of them all. The Dragon shape was dictated by aerodynamic needs. It increases weight per volume and manufacturing complexity.

[go4mars]

Because... side mounted nature of the dragon engines, could the additional fuel be in a trunk below the dragon? This would mean it could be there all the way from earth, and could be dropped during ascent from the moon. (big drawback, you couldn't use the dragon landing gear, which I guess may be sufficient for bearing the much greater weight of the ascent propellant if in lunar gravity.. on the other hand it occurs to me having your heat shield that close to the regolith with the thrust throwing stones around could be bad. Is this a lunar only dragon?)

Some good points and interesting thoughts in there. 

So trunk has some internal tanks, and trunk protects the heat shield during both landing and takeoff.  With some of those small nose-cone retractable circular solar arrays (or maybe exceptional batteries) the biggest outstanding challenge might be getting the fuel from the trunk to the dragon's superdracos.   

As to strength of trunk, it already needs to be able to handle the weight of a loaded dragon at 4 or 5 g's (during takeoff from Earth).
So conceivably it could support the partly full trunk tank mass of 6x dragon at lunar gravity. 

[rockinghorse]

Why not strip a Dragon to bare minimum..a separate lander. Strip heat shield.. parachutes.. Aero panels and super Draco's. Add back the bare minimum vacuum optimized super Draco's monted vertical(no cosine loss). Could add inflatable airlock. Add fuel in space where heat shield removed. Would the mass/fuel savings be enough to justify a separate dragon based disposable lander?

Because it is cheaper to design new Lunar Module. The point of Dragon is that it is capable to land on Earth. The Moon landing capability is free byproduct.

However other suggestion to have extra fuel tank in trunk, is better.

Although I would still land the whole upper stage to the Moon. Also I think that to have separate upper stage and Dragon is unnecessary complication and I think that Dragon is there only because SpaceX cannot yet make reusable upper stage. But as soon as SpaceX can return the upper stage on Earth, they will discard Dragon and merge it with upper stage.

[go4mars]

About 2 years ago, Elon mentioned that he wasn't going to work hard on upper stage reuse for 5 or 6 years.  One way to take that: waiting until raptor is available.

 If it stays as a separate stage, I suspect it will be returnable from geostationary at least.  If incorporated with the spaceship, then BEO return is probable.  I think there's more future flexibility and delta v advantage to keeping them separate, but unlike some other guy I haven't had a team of brilliant engineers paid to think about Mars architectures for a decade. 

Although it's conceivable maybe to have a big raptor upperstage and/or raptor powered spaceship launched by FH, I think those will wait for bigger, beefier 1st stage cores. 

So for the purpose of this thread, FH roughly as envisaged, and crew dragon, are the baselined elements.

[guckyfan]

About 2 years ago, Elon mentioned that he wasn't going to work hard on upper stage reuse for 5 or 6 years.  One way to take that: waiting until raptor is available.

Possible, but I think they may want the Falcon upper stage returnable as proof of concept and improve on it in the Raptor upper stage. I may be wrong though and they see that as an unnecessary expense of money and engineering capacity.

So for the purpose of this thread, FH roughly as envisaged, and crew dragon, are the baselined elements.

Agree, they will not spend too much on the Falcon/Dragon family. They can fly the missions that bring in the money now. Interplanetary and the moon can wait for the Raptor family unless someone pays really big for it.

[sdsds]

Quoting the whole thing because it is a little way back..

[...] The propellant tanks in this mission kit would be sized to meet the demands of the mission type with the largest delta-v requirement.

[...] Maybe the dragon engines are powerful enough if the fuel lasts.. but could such engines last to give you around 2km delta-v if the fuel was available?

Yes in terms of total duration of firing. That's because their design use involves multiple firings for propulsive landings on Earth. Would their design allow them to burn all of that propellant in a single go? Maybe. Maybe not. For the sake of the fantasy I'm guessing "Yes."

Another thought re the picture  (missing from the quoted version).. Because of the weird side mounted nature of the dragon engines, could the additional fuel be in a trunk below the dragon? This would mean it could be there all the way from earth, and could be dropped during ascent from the moon.

In my version of the fantasy, the propulsion module in the location where the trunk goes now would be a crasher descent stage. Else, how could the ascent propellant (much less the capsule) be delivered to the lunar surface?

[Ben the Space Brit]

Because of the weird side mounted nature of the dragon engines, could the additional fuel be in a trunk below the dragon?

IIRC, at one point, one of the options for the trunk is extra propellent tanks for the hypergolic fuel system. I don't know if that's still the case.

In any case, assuming that Superdraco-VAC (with added expansion nozzles) has a high enough Isp, there's no reason why a simple propulsion module can't be contrapted out of a maximum-length trunk.

Regarding a lander? The Dragon's hatch isn't really ideal for getting in and out with an EVA suit and PLSS pack, so I'd flip the pressure vessel on its side so that the hole for the CBM hatch could be used as the surface hatch and the LIDS is attached to where the crew hatch would be on the Dragon. The pressure vessel is basically hexagonal in profile; it's not ideal but is easily big enough for a 2-crew landing party plus a few days' consumables.

An off-the-shelf Dragon could be used as the basis of a cargo lander with the pressure vessel replaced with unpressurised cargo racks and a much larger access port.

[Jcc]

If the modified trunk engines and fuel supply are to serve for both descent and ascent, plus return to earth, that seems to be asking a lot of them.

Apollo has 3 separate propulsion units for that. The command module didn't land to reduce propulsion requirements for descent and ascent. The LM was made of very thin and light material, plus half of it was left behind on the lunar surface to save fuel on ascent.

Even the Constelation plans followed that pattern, so what is the huge advance in propulsion technology at will allow you to carry all the fuel needed to land, ascend and return to earth down to the lunar surface?

[Rocket Science]

If you pre-position a tanker in orbit you could refuel in orbit prior to PDI and TEI...

[KelvinZero]

In my version of the fantasy, the propulsion module in the location where the trunk goes now would be a crasher descent stage. Else, how could the ascent propellant (much less the capsule) be delivered to the lunar surface?

I had imagined a crasher stage also, possibly even the second stage that is already beneath the trunk at the time of launch, supposing we find a way to refuel it.. but I hadn't thought about it that deeply, just that the mass you put above could alternatively be beneath.

Two other things occur to me:
*The unusual rocket configuration could also allow the Dragon to drop really heavy payloads right on the surface, a la Curiosity.
*Add some legs to the crasher stage and the Dragon could land that too, effectively adding throttle ability to what might be a standard in-space stage.

[Ben the Space Brit]

Here's a thought: Some of the Mars One art I've seen has shown Dragon-like hab modules daisy-chained all in a row. I know that Dragon is quite small but is there any reason why one or two couldn't be contrapted to act as a crew shelter? I'm thinking of a sleeping area and maybe relaxation area for an extended surface stay.

I know this all sounds needlessly elaborate but, if we're thinking of doing lunar surface using nothing but re-purposed FH and Dragon bits, something like this might be useful.

[KelvinZero]

If the modified trunk engines and fuel supply are to serve for both descent and ascent, plus return to earth, that seems to be asking a lot of them.

Apollo has 3 separate propulsion units for that. The command module didn't land to reduce propulsion requirements for descent and ascent. The LM was made of very thin and light material, plus half of it was left behind on the lunar surface to save fuel on ascent.

Even the Constelation plans followed that pattern, so what is the huge advance in propulsion technology at will allow you to carry all the fuel needed to land, ascend and return to earth down to the lunar surface?

That wasn't really what I was suggesting... but I think there is a potential huge advance on the horizon and sort of on topic:
F9R could potentially deliver propellant to orbit 100 times cheaper than today. We could refuel those massive second stages we are currently throwing away and use them as our earth departure stages. (add SEP and ISRU and you could refuel in lunar orbit and on the lunar surface as well, land the things on the moon and then send them all the way home to land propulsively on earth)