Author Topic: Reusable FH/Raptor-US Minimalist Lunar Architecture  (Read 38972 times)

Offline Paul451

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #80 on: 04/03/2016 10:09 am »
{snip}
As I said, I like the imagery of a space garage. I just don't see the point of it in a "minimalist" or near-term architecture. Sure, once you have ten landers operating around the clock (or which two or three are in service/repair/upgrade at any given time) then it might make sense to have a central facility in lunar orbit (or at a Lagrangian staging point), and if you are pretty much constantly repairing some of the landers, it makes sense (IMO) to have an unpressurised enclosure to simplify EVAs. But when you only have one or two landers and, say, four flights a year, or similar realistic near-term flight rates, it just doesn't make sense.
{snip}
This is asking a major high level question - are the landers expendable (single use) or reusable and serviced/replaced in space?

It's not. Nothing I said assumed expendable landers.

There is no reason for a orbital "garage" when talking about an architecture with only one or two -- reusable! -- landers and a small handful of missions per year.

There's no stockpile of fuel requiring a depot, you refuel the landers directly. The incoming fuel supply is the "depot".

There's no stockpile of parts. The parts travel with the crew doing the repair mission.

And the mission hardware, such as the crew capsule, simply docks directly with the lander for crew transfers.

Quote
A lunar orbiting spacestation is likely to have [...] an escape pod of some sort

Escape pods aren't a thing in space; only in SF.

Offline A_M_Swallow

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #81 on: 04/03/2016 02:22 pm »
{snip}
Escape pods aren't a thing in space; only in SF.

The ISS could be SF.

Dragon and CST-100 will be able to act as escape pods.

Offline A_M_Swallow

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #82 on: 04/03/2016 02:25 pm »
{snip}
As I said, I like the imagery of a space garage. I just don't see the point of it in a "minimalist" or near-term architecture. Sure, once you have ten landers operating around the clock (or which two or three are in service/repair/upgrade at any given time) then it might make sense to have a central facility in lunar orbit (or at a Lagrangian staging point), and if you are pretty much constantly repairing some of the landers, it makes sense (IMO) to have an unpressurised enclosure to simplify EVAs. But when you only have one or two landers and, say, four flights a year, or similar realistic near-term flight rates, it just doesn't make sense.
{snip}
This is asking a major high level question - are the landers expendable (single use) or reusable and serviced/replaced in space?

It's not. Nothing I said assumed expendable landers.

There is no reason for a orbital "garage" when talking about an architecture with only one or two -- reusable! -- landers and a small handful of missions per year.

There's no stockpile of fuel requiring a depot, you refuel the landers directly. The incoming fuel supply is the "depot".

There's no stockpile of parts. The parts travel with the crew doing the repair mission.

And the mission hardware, such as the crew capsule, simply docks directly with the lander for crew transfers.

Quote
A lunar orbiting spacestation is likely to have [...] an escape pod of some sort

Escape pods aren't a thing in space; only in SF.

To perform major repairs the crew capsules would need to have robotic arms.

Offline TrevorMonty

Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #83 on: 04/03/2016 05:07 pm »
Any EML1 based reusable lander can act as an escape pod. Having a 2nd lander at EML1 would allow rescue of crew from anywhere between LEO and lunar surface. With 6-7km/s DV it can easily reach ISS from EML1 if return capsule is faulty.

Offline Paul451

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #84 on: 04/04/2016 07:56 am »
Escape pods aren't a thing in space; only in SF.
The ISS could be SF.
Dragon and CST-100 will be able to act as escape pods.

Your original list of ingredients had:

Quote
A lunar orbiting spacestation is likely to have a couple of landers, one or two manned spacecraft from Earth, an escape pod of some sort [...]

You were clearly talking about an escape pod that is distinct from the normal manned capsules.

And that is not a thing. Won't be until we have true space-ships.

To perform major repairs the crew capsules would need to have robotic arms.

Not really. A lander is not a space-station.

Offline hkultala

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #85 on: 04/04/2016 08:49 am »
Any EML1 based reusable lander can act as an escape pod. Having a 2nd lander at EML1 would allow rescue of crew from anywhere between LEO and lunar surface. With 6-7km/s DV it can easily reach ISS from EML1 if return capsule is faulty.

Did you take into account what ISS inclination does to the delta-v requirement of reaching it?

Offline A_M_Swallow

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #86 on: 04/04/2016 10:30 am »
Escape pods aren't a thing in space; only in SF.
The ISS could be SF.
Dragon and CST-100 will be able to act as escape pods.

Your original list of ingredients had:

Quote
A lunar orbiting spacestation is likely to have a couple of landers, one or two manned spacecraft from Earth, an escape pod of some sort [...]

You were clearly talking about an escape pod that is distinct from the normal manned capsules.

And that is not a thing. Won't be until we have true space-ships.


I have heard of the Crew Return Vehicle and what it eventually turned into.
https://en.wikipedia.org/wiki/Crew_Return_Vehicle

Quote

To perform major repairs the crew capsules would need to have robotic arms.

Not really. A lander is not a space-station.

A reusable lander will need repairing. Reusable launch vehicles need repairing so a lander that can do say 10 trips without repairs is still in the future.

If we do not have a spacestation than the repair arms for the landers have to go on the transfer vehicles (crew capsules). The Space Shuttle used its arm to repair the Hubble Telescope.

Offline TomH

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #87 on: 04/04/2016 03:57 pm »
I created the thread to discuss a minimalist lunar architecture based on FH with Raptor US. You guys are getting way beyond minimalistic. The whole idea was to create an affordable architecture, not to see if we could give it NASAesque complexity. Please bring the discussion back within the parameters.

Offline A_M_Swallow

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #88 on: 04/04/2016 04:56 pm »
I created the thread to discuss a minimalist lunar architecture based on FH with Raptor US. You guys are getting way beyond minimalistic. The whole idea was to create an affordable architecture, not to see if we could give it NASAesque complexity. Please bring the discussion back within the parameters.

The minimum needed for a single trip may be very expensive for multiple trips. For example expendable landers are OK for a single trip but buying and launching 10 landers for 10 trips is no longer minimalist.

Offline savuporo

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #89 on: 04/04/2016 06:30 pm »
I created the thread to discuss a minimalist lunar architecture based on FH with Raptor US. You guys are getting way beyond minimalistic. The whole idea was to create an affordable architecture, not to see if we could give it NASAesque complexity. Please bring the discussion back within the parameters.
The main problem is that reasonable ascent propulsion does not exist. Which is not  to say that it couldn't be built, but about 5 years of development time, give or take.
Orion - the first and only manned not-too-deep-space craft

Offline TrevorMonty

Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #90 on: 04/04/2016 07:18 pm »
I created the thread to discuss a minimalist lunar architecture based on FH with Raptor US. You guys are getting way beyond minimalistic. The whole idea was to create an affordable architecture, not to see if we could give it NASAesque complexity. Please bring the discussion back within the parameters.
You need to define minimalistic. It can be any of the following but not all and they all have trades.

Launches per mission
Crew
Time on surface
Development costs of new equipment
.



Offline TrevorMonty

Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #91 on: 04/04/2016 07:32 pm »
Any EML1 based reusable lander can act as an escape pod. Having a 2nd lander at EML1 would allow rescue of crew from anywhere between LEO and lunar surface. With 6-7km/s DV it can easily reach ISS from EML1 if return capsule is faulty.

Did you take into account what ISS inclination does to the delta-v requirement of reaching it?
3.77km/s see link below.

http://phobosorbust.blogspot.co.nz/2016/02/interorbital-exchange-part-1-cis-lunar.html

Offline MATTBLAK

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #92 on: 04/04/2016 10:04 pm »
I created the thread to discuss a minimalist lunar architecture based on FH with Raptor US. You guys are getting way beyond minimalistic. The whole idea was to create an affordable architecture, not to see if we could give it NASAesque complexity. Please bring the discussion back within the parameters.

See my earlier post about the 2x Falcon Heavy (EDS/LOI stages) & 2x Falcon 9 launched Dragon's to achieve minimal, Sortie missions of a week or less for 2x crew. Man-rated Dragons are coming soon, but I sometimes wonder if we'll ever see a Falcon Heavy at this rate!! Yes, extra development of the Lunar Dragons would be needed - using Trunk-based crasher stages or propellant drop tanks for the Draco engines for descent duties. Not to mention increasing the Dragon's onboard propellant load for the Dracos to give the Dragons enough delta-vee to achieve an ascent to 50,000 feet to the Command Dragon. Anyone know the current delta-vee for a Dragon Version 2?
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Offline TomH

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #93 on: 04/05/2016 01:22 am »
You need to define minimalistic.

Fair enough. 1) Minimal new development, 2) Minimal cost.  If many launches of an entirely reusable LV are required, but cheaper, O.K.

Things it does not include: space stations in lunar orbit, hangars in lunar orbit, etc. That is the stuff to which I am referring. Grandiose notions defeat the entire purpose of using what SpaceX already is planning. Grandiosity is already killing too much in aerospace: JWST, F-35, etc.

In that ACES now is to be built, that is acceptable IF the cost is not prohibitive. I think, however, that a reusable Raptor US would be cheaper.

Offline Paul451

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #94 on: 04/05/2016 05:30 am »

I'd suggest a more generally paraphrasing, you're asking "what's a lowest cost manned landing on the moon"?

If we do not have a spacestation than the repair arms for the landers have to go on the transfer vehicles (crew capsules). The Space Shuttle used its arm to repair the Hubble Telescope.

The primary purpose of the arms is to move large payloads, or to relocate large modules around the ISS. A secondary function was as a handy base for astronauts to work from.

However, for a lander and capsule docked together, the primary function of the robot arm is not necessary. By including a large space-station, you merely increase the costs and the number of systems that need repair.

Repairs to a lander would be carried out internally, passing through the docking adaptor, and externally via EVAs conducted using various handle and attachment points build into the lander, using the capsule as an airlock.

You're confusing how things can be done with how they must be done.

Offline Paul451

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #95 on: 04/05/2016 06:06 am »
using Trunk-based crasher stages

The trunk isn't that kind of service module. A crasher stage would be based around a modified upper stage.

Indeed, for any BEO mission using FH, that's going to be a good addition: A docking insertion stage than is launched separately to the main payload(s), docking in LEO. Eats some Oberth, but increases your overall available payload mass.

Otherwise, how do you get the crew capsule out of LEO?

Anyone know the current delta-vee for a Dragon Version 2?

Numbers floating around are just under 1km/s.

However, the SuperDraco's are wildly overpowered for a lunar landing, even throttled down. Hell even using just four would probably be too much. You'd probably want to engineer something half way between the Draco RCS thrusters and the SuperDraco abort/landing thrusters.

(Their Isp is also pretty rubbish. 240s. 65% propellant mass fraction for 2.5km/s (EML1-LS), 55% PMF for 1.9km/s (VLLO-LS). Bleh.)

But since you don't need the heat shield, if you've got plenty of thrust, you don't need to jettison the trunk. So an extended cargo trunk with landing gear could be an interesting (while still fairly low cost) addition. Jettison the trunk (or at least the surface-mission portion) during launch.

Not reusable. But if you are talking about a crasher stage, we are obviously assuming a quick'n'dirty throw-away mission.

[edit: Kestrel would be a nice landing engine.]
« Last Edit: 04/05/2016 06:37 am by Paul451 »

Offline MATTBLAK

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #96 on: 04/05/2016 06:53 am »
Agreed about the Kestrel. I only mentioned a Trunk based Crasher stage because someone more qualified and connected than me has mentioned it elsewhere before. A bare-bones Crasher stage could be fashioned around a Kestrel engine and prop tank cluster, mounted in a tubular chassis that bolts to where a Dragon heatshield normally would be. A mini RCS quad set of x4 or even x3 (120 degree spacing) could be mounted on the framing perimeter and share the LOX/Kero propellant supply. Overall, the stage would be sort of like the Russian BRIZ stage in concept. Also; imagine something like the Mercury spacecraft retropack, only larger.
« Last Edit: 04/05/2016 06:54 am by MATTBLAK »
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Offline Paul451

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #97 on: 04/05/2016 12:01 pm »
Agreed about the Kestrel. I only mentioned a Trunk based Crasher stage because someone more qualified and connected than me has mentioned it elsewhere before.

I've seen people talk about it before. But it doesn't make sense. The Dragon trunk is an empty space to store cargo, some solar panels and associated power converters. It's not a "service module" in the Apollo sense, which is what people seem to be confusing it with.

To turn it into a propulsion stage, you have to add... the entire propulsion stage.

Offline A_M_Swallow

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #98 on: 04/05/2016 12:49 pm »

I'd suggest a more generally paraphrasing, you're asking "what's a lowest cost manned landing on the moon"?

If we do not have a spacestation than the repair arms for the landers have to go on the transfer vehicles (crew capsules). The Space Shuttle used its arm to repair the Hubble Telescope.

The primary purpose of the arms is to move large payloads, or to relocate large modules around the ISS. A secondary function was as a handy base for astronauts to work from.

However, for a lander and capsule docked together, the primary function of the robot arm is not necessary. By including a large space-station, you merely increase the costs and the number of systems that need repair.

Repairs to a lander would be carried out internally, passing through the docking adaptor, and externally via EVAs conducted using various handle and attachment points build into the lander, using the capsule as an airlock.

You're confusing how things can be done with how they must be done.

The main engines on a Centaur lander are RL20s, 13.6 feet long by 7 feet in diameter. Without help astronauts will have problems pushing those around.

Offline mitresaw

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Re: Reusable FH/Raptor-US Minimalist Lunar Architecture
« Reply #99 on: 11/01/2016 06:43 pm »
great thread.  the glimmer of possibility is delicious.  the minimalist parameters need a little expansion imo because a single launch etc. to put 4 guys on the moon gives us what return?  if they can develop a system that makes each subsequent mission cheaper or safer or productive, then it is more realistic. if you have to barrow money to put this in motion you have to show you can pay it back. ;D 

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