Reusable LSAM

cIclops · 2006-05-27 06:17:00

Given that the ESAS rejected the lunar direct option because it required a 200mt launch lift, now that 170+ mt may be available with the RS-68/5-segment RSRB CaLV
perhaps a fully reusable LSAM is possible?

This vehicle would be lifted by the CaLV with an EDS as before, and crew would rendezvous using the CEV that would be left in LEO. The LSAM would then depart EOR using a larger EDS and descend to the lunar surface, then ascending and returning to EOR by using aggressive aerobraking and finally docking with the CEV. The crew could also be transferred from and to the ISS.

Primary advantages:

o simplified design, same engine & tanks used for descent and ascent
o vehicle available for inspection on return
o no LOR
o potential reuse by EOR refueling (either from EDS or orbital depot)

GCNRevenger · 2006-05-27 07:56:32

Huh? 170MT is waaay outside the realm of possibility with any variation of the CaLV, unless you slap a nuclear rocket engine on the EDS.

And lugging along a heavy-duty aerobrake shield (which must be quite sturdy for Earth's thick atmosphere) all the way to the Lunar surface and back would impose a terrible payload penalty.

Same with launching to an ISS orbit, that there is a substantial penalty for going to its 52 degree orbit instead of equitorial orbit. Plus, the ISS simply won't be there that much longer.

Going through all this trouble to save the LSAM doesn't make a whole lot of sense, they aren't that expensive as to justify developing such a scheme.

cIclops · 2006-05-27 08:53:52

Huh? 170MT is waaay outside the realm of possibility with any variation of the CaLV, unless you slap a nuclear rocket engine on the EDS.
And lugging along a heavy-duty aerobrake shield (which must be quite sturdy for Earth's thick atmosphere) all the way to the Lunar surface and back would impose a terrible payload penalty.
Same with launching to an ISS orbit, that there is a substantial penalty for going to its 52 degree orbit instead of equitorial orbit. Plus, the ISS simply won't be there that much longer.
Going through all this trouble to save the LSAM doesn't make a whole lot of sense, they aren't that expensive as to justify developing such a scheme.

Not according to Kraisee over on nasaspaceflight.com

My latest sets of calculations are based on a number of basic assumptions: I'm assuming all the latest available 5-seg PBAN SRB and J-2X figures (still to be officially confirmed of course, but I have now verified them all from at least two separate sources). I'm also assuming the performance of the RS-68 remains identical to the current units too.
The only 'X' factor I can't get confirmation for yet is the final length of the Core Stage. My tests indicate that optimal performance occurs now with 3.3m lb of propellant in the Core stage, which is about 50% larger capacity than the original CaLV tank holds. You automatically increase the capacity by about 33% by increasing the overall diameter of the stage to 10.06m, but that leaves a further extension to the length to achieve the optimum performance configuration. Increase the length by ~10% and you can get 40% increase in propellant. Increase it by ~25% and you get the optimum 50% payload capacity increase.
Increase the Core propellant by about 33% (no lengthening required) and you can broadly match the original vehicle's performance figures of 146.6mT. Lengthen the stage and increase the Core propellant capacity by 40%, and the Net Payload figure climbs to 167.2 mT (including EDS) to 30x160 nm, 28.5 degree orbit. For the full 50% Core propellant increase, the Net Payload figure becomes an awesome 177.3 mT (inc. EDS) to the same orbit!

As to the aerobraking shield, this would consist of the LSAM engine, landing structure and the solar panels fitted underneath to protect the tanks.

Optional transfer to the ISS would be done by the CEV SM. I think the ISS will be there until at least 2017, probably much longer once a cheaper COTS is available.

The primary objective is not to save the LSAM but to reduce risk by simplifying the architecture by eliminating LOR and returning the vehicle intact for inspection. Reuse would be a bonus.

RedStreak · 2006-05-27 09:01:34

Given that the ESAS rejected the lunar direct option because it required a 200mt launch lift, now that 170+ mt may be available with the RS-68/5-segment RSRB CaLV
perhaps a fully reusable LSAM is possible?
Primary advantages:
o simplified design, same engine & tanks used for descent and ascent
o vehicle available for inspection on return
o no LOR
o potential reuse by EOR refueling (either from EDS or orbital depot)

I think a reuseable LSAM might be a good idea but we would need to develop something like a single-stage LSAM. I often wonder why the lunar descent engine can't simply be used twice. The SSME isn't the only engine capable of restart; Lockeed and its Centaur upper stages and numerous other disposable rocket engines, including the J-2s from the old Saturns, were capable of stopping and then performing a second burn. The only factor that may be considered is lift-off with the landing gear versus just the crew cabin (which the current ascent stage pretty much is).

If its a simplified single-stage craft it could be modified for refuel and reuse later on too.

gaetanomarano · 2006-05-27 10:27:23

to 167.2 mT (including EDS) to 30x160 nm, 28.5 degree orbit. For the full 50% Core propellant increase, the Net Payload figure becomes an awesome 177.3 mT (inc. EDS) to the same orbit!

if the 5xRS-68s + 2x5-seg.SRBs CaLV can lift up to 177 mT...

then, "my" Super SLV (with 3-4 SSME and 3x4-seg.SRBs) can lift MORE than 135 mT...

.

gaetanomarano · 2006-05-27 11:03:26

perhaps a fully reusable LSAM is possible?

a reusable-LSAM is an EXCELLENT idea with MANY advantages!

however, a refuelable version is not efficient because it must lift from the moon also the tank's weight

my suggestion is to build a 10+ times reusable-LSAM with expendable descent-fuel tanks

the first 30 missions will need only FOUR reusable-LSAM (three for the missions + one spare LSAM) than may wait docked to a little long-life lunar orbit module with assembly tools/canadarm3, a pressurized living/emergency module for the astronauts, solar panels, extra (orbital/lunar) life support (oxygen, water, food, etc.) and a little engine for orbital adjust/moving

one (of MANY) advantages of a reusable-LSAM is that the lunar-missions/landing-sites may DOUBLE, triple (or MORE)

since the CEV/SM life will be up to SIX months (in stand-by) and the lunar-orbit-module can be built (like the ISS) for 15+ years of life (with re-supply) EACH 4-astronauts' crew can accomplish TWO-THREE or MORE lunar missions to TWO-THREE or MORE different landing sites!!!

the only need the LSAM's descent-TANKS/descent-ascent-FUEL for 3+ missions sent from earth with the CEV/SM and assembled in lunar orbit with the assembly module/tool/canadarm3

also, since in the original ESAS plan the LSAM fuel will be used also for CEV/SM/LSAM's LOI, the reusable-LSAM (sent alone) will needs LESS fuel for LOI and ONLY ONE TIME, then, in all lunar missions, it will need only the descent/ascent fuel while the crew+cargo weight will be TWICE or more the crew+cargo weight of an expendable-LSAM

------------------------------------

but I suggest you to don't talk to much (on space-forums and blogs) of "reusable-LSAM"... if you don't want to be attaked (like other peoples, that, in last six months, have suggested the same idea) by dozens of furious " " " " "indipendent" " " " " experts... because the LSAM-business of the first 30 missions will be...

with expendable-LSAMs:

$5 billion R&D + $800 million x 30 LSAMs = $29 billion

with reusable-LSAMs:

$6 billion + $1 billion x 4 LSAMs + $100 million x 30 refueling-tanks = $13 billion

also... four reusable LSAMs + one lunar-orbit-module may KILL (both) the CLV and the CaLV !!!!!

because 60%+ of a moon missions weight is due to the LSAM + EDS fuel for TLI with three times the CEV/SM weight!

then, a 177, or 150 or 130 mT CaLV will be COMPLETELY UNNECESSARY since each mission will need to launch only the CEV/SM + 20 mT of new LSAM tanks/fuel and a smaller EDS... probably less than 80 mT per mission!

with only 80 mT per mission to launch, a single "small-CaLV" with two 4-seg.SRB and 2 SSME or RS-68 will be sufficient and the CLV simply deleted!

.

RedStreak · 2006-05-27 11:29:42

perhaps a fully reusable LSAM is possible?
a reusable-LSAM is an EXCELLENT idea with MANY advantages!
however, a refuelable version is not efficient becaus eit must lift from the moon also the tank's weight
my suggestion is to build a 10+ times reusable-LSAM with expendable descent-fuel tanks

Keep in mind for it to be reuseable it needs to be refueled otherwise you're talking about either a one-time use lander or something like the Mars Direct lander that serves as a surface module. I don't think a LSAM ascent stage can be reuseable like the CEV.

Limiting its reuse is a good idea too - perhaps on its final landing it could be left on the surface for, say, fuel storage.

Refueling isn't as big a deal as many people here seem to fret about. The Russian Progress regularly refuels the ISS; it doesn't just perform burn maneuvers for the station - that's just a cost-saver feature done before the Progress is used up.

A single-stage LSAM isn't inconceiveable - a two-stage lander has its own complexities and downsides (it DOES require two engines, two seperate propulsion systems - I'm suprised people aren't ragging about that); the only difference between the two is that the two-stage has the benefit of already being tested via the old LEM.

Sure it will be heavier than just an ascent stage - keep in mind however when it lifts off it will be only loaded down with barely half the fuel it originally landed with - it simply needs enough to get it into lunar orbit and between it and the CEV there'd be sufficent rendevous fuel.

To me the only question is how to get the LSAM back to LEO for refueling. Aerobraking is out of the question and as much as I support ion propulsion those solar panels would be too bulky. Maybe an ion tug could bring it down to LEO.

Again to summarize an entire single-stage LSAM is feasable, but bringing it back for reuse is the question.

Rxke · 2006-05-27 12:00:44

Sure it will be heavier than just an ascent stage - keep in mind however when it lifts off it will be only loaded down with barely half the fuel it originally landed with - it simply needs enough to get it into lunar orbit and between it and the CEV there'd be sufficent rendevous fuel..

I think you'd end up with a *dramatic* weight-penalty. You would end up with a lander that's no good, because it cannot land anything useful (cargo)

cIclops · 2006-05-27 12:06:03

Aerobraking is out of the question ...

Why if it's combined with an orbital insertion burn to reduce velocity? The solar panels would be needed for internal spacecraft power only as the CEV and its panels would be left in LEO. So why not mount them under the tanks and use them to increase the braking area and protect the tanks at the same time. There would be little additional mass and they would provide a large aerobraking surface, just as MRO and MGS successfully used. Together with the landing structure and engine there should be plenty of area to dissipate the frictional energy, the process would be spread out over several days.

cIclops · 2006-05-27 12:17:00

Sure it will be heavier than just an ascent stage - keep in mind however when it lifts off it will be only loaded down with barely half the fuel it originally landed with - it simply needs enough to get it into lunar orbit and between it and the CEV there'd be sufficent rendevous fuel..
I think you'd end up with a *dramatic* weight-penalty. You would end up with a lander that's no good, because it cannot land anything useful (cargo)

This proposal is based on the predicted substantial extra capacity of the CaLV (+50mt) to lift the larger EDS and LSAM tanks and fuel together with the weight saving of a single engine/tank design, plus eliminating the need to take the 20mt CEV to LLO and back.

RedStreak · 2006-05-27 12:44:13

Sure it will be heavier than just an ascent stage - keep in mind however when it lifts off it will be only loaded down with barely half the fuel it originally landed with - it simply needs enough to get it into lunar orbit and between it and the CEV there'd be sufficent rendevous fuel..
I think you'd end up with a *dramatic* weight-penalty. You would end up with a lander that's no good, because it cannot land anything useful (cargo)

Actually no. The manned LSAM is pretty devoted to the ascent stage and crew. However an unmanned LSAM, which would be delivering the heavy-duty cargo, would land with only the fuel required for a controlled landing. Therefore any added weight needed for lift-off would only be an issue for a manned single-stage LSAM.

Don't try to talk about manned landers delivering cargo - besides maybe a few hundred pounds of food/water, and perhaps some small instrumentation it can't compete against a lander with the manned portion chopped off and devloped to heavy loads.

cIclops · 2006-05-27 12:48:42

Don't try to talk about manned landers delivering cargo - besides maybe a few hundred pounds of food/water, and perhaps some small instrumentation it can't compete against a lander with the manned portion chopped off and devloped to heavy loads.

The recent NASA solicitation for the crew LSAM requires minimum delivery of 500kg of cargo down and 100kg up.

RedStreak · 2006-05-27 13:11:18

Why if it's combined with an orbital insertion burn to reduce velocity? The solar panels would be needed for internal spacecraft power only as the CEV and its panels would be left in LEO. There would be little additional mass and they would provide a large aerobraking surface, just as MRO and MGS successfully used.

I like your thinking, but I'm not certain. The MRO and MGS would be barely a quarter the size of LSAM; when its something small its easier when its massive and bulky it tends to be difficult at best. There'd be a huge amount of momentum/velocity.

I don't think there'd be enough fuel left in LSAM for even a partial orbital break, but possibly the CEV service module could do something there - if LSAM and CEV were still docked ala Apollo 13 on its return trajectory perhaps the service module could provide the burn. No harm done since the whole assembly is en route to Earth's atmosphere anyway.

I think this may lead to a workable idea...

Ok, a single-stage LSAM would rendevous with the CEV as in the normal architecture - empty save for some maneuvering propellant, no ion drive no additional frills. CEV would do escape maneuver, the whole assembly en route for Earth. Nearing Earth CEV performs a final burn to slow velocity but still keeping target for atmospheric entry. Service module jettisons burns up, CEV reenters and lands, but the LSAM would maneuver to graze the upper atmosphere. It would likely take at least a month for it to reach a circular LEO, at which point a refueling pod can be launched (perhaps even a modified Progress is the Russians get in on this). New CEV rendevouses, and the CaCLV sends up the escape stage. New mission launched, lands, repeat cycle.

Given this aerobraking concept though I would recommend limiting LSAM down to 5, maybe 6 reuses. This whole revised architecture would have to be saved when the CEV is upgraded - perhaps as a prerequisete to Martian flights. Also this is for manned lunar flights - cargo would be set up via CaCLV only.

gaetanomarano · 2006-05-27 14:17:01

...Service module jettisons burns up, CEV reenters and lands, but the LSAM would maneuver to graze the upper atmosphere. It would likely take at least a month for it to reach a circular LEO, at which point a refueling pod can be launched...

send back the LSAM to earth orbit to re-fuel it needs and IMPRESSIVE quantity of extra-fuel to... exit the lunar orbit with twice the CEV/SM weight, brake it to earth orbit with six times the gravity... AND... also GIANT quantities of extra-fuel#2 to launch the CEV/SM/LSAM+extra-fuel#1 system towards the moon and extra-fuel#3 to brake the CEV/SM/LSAM+extra-fuel#1 to lunar orbit

that solution needs a 300+ mT payload CaLV

the ONLY way is to refuel the LSAM in lunar orbit while parking it to a little lunar-ISS-module

about the reusable-LSAM...

I think that both version, with reusable or expendable ascent-fuel tanks, can be built, but the "expendable tanks" version is better, for two reasons:

1. lift to lunar orbit the empty tanks needs extra ascent-fuel/weight that, with expandable tanks, can be used to land 1+ mT of (very important and precious) extra payload on the moon

2. despite a reliable refuel system can be develped, it needs more time and money, while, an expendable-tanks/fuel system is faster and cheaper to develop and faster, safer and very easy to use... it will be fast, safe and easy to use like change the batteries of a cellurar phone!!!

the space already is a very risky place, then, the better and safer way is to always use the simplest solutions

.

Rxke · 2006-05-27 14:42:44

Don't try to talk about manned landers delivering cargo - besides maybe a few hundred pounds of food/water, and perhaps some small instrumentation it can't compete against a lander with the manned portion chopped off and devloped to heavy loads.

So you'd need two landers for any mission instead of one. That's not likely to happen, at least not in the first phase, when you want to have some short-duration precursor missions, before you decide where to set up shop for real.

RedStreak · 2006-05-27 14:46:34

So you'd need two landers for any mission instead of one. That's not likely to happen, at least not in the first phase, when you want to have some short-duration precursor missions, before you decide where to set up shop for real.

No no no.

One lander is directly for the manned excursion but the second would be a cargo vehicle dedicated to delivering a base element.

cIclops · 2006-05-27 15:41:09

send back the LSAM to earth orbit to re-fuel it needs and IMPRESSIVE quantity of extra-fuel to... exit the lunar orbit with twice the CEV/SM weight, brake it to earth orbit with six times the gravity... AND... also GIANT quantities of extra-fuel#2 to launch the CEV/SM/LSAM+extra-fuel#1 system towards the moon and extra-fuel#3 to brake the CEV/SM/LSAM+extra-fuel#1 to lunar orbit
that solution needs a 300+ mT payload CaLV

In ths scenario the CEV would not travel with the LSAM to the moon, but the LSAM would need more fuel to land the extra mass and much more to take off. On the positive side LSAM would save the whole weight of the ascent propulsion system and reduce the weight of the structure, power, enviroment and avionics by only having a single set of these elements. ESAS gave a mass of about 45 mt for the LSAM of which 12mt is inert mass, perhaps 3 mt of this could be saved. The extra 50mt capacity of the CaLV might make it possible, the weight of fuel seems to be the critical factor.

SpaceNut · 2006-05-27 17:36:44

I had tried to create a topic of discusion along time ago but at that time there was not a name for the lunar lander. This thread Earth Re-entry, Moon or Mars Lander and - return vehicle. One do all, part of CEV? and in several of the Moon direct threads we did cover many of the needs to establish this.

RedStreak · 2006-05-28 00:39:25

In ths scenario the CEV would not travel with the LSAM to the moon, but the LSAM would need more fuel to land the extra mass and much more to take off. On the positive side LSAM would save the whole weight of the ascent propulsion system and reduce the weight of the structure, power, enviroment and avionics by only having a single set of these elements. ESAS gave a mass of about 45 mt for the LSAM of which 12mt is inert mass, perhaps 3 mt of this could be saved. The extra 50mt capacity of the CaLV might make it possible, the weight of fuel seems to be the critical factor.

That in turn may also be critical on whether methane is used. I may prove to be lighter than whatever fuel is chosen - hydrogen likely would be heavy because of the fuel tank accomidations for it.

cIclops · 2006-05-31 08:31:55

To avoid talking too much nonsense here are some rough numbers:

Assuming:

LSAM dry mass 12 mt (ESAS architecture)
single LOX/CH4 LSAM engine; Ve=3034 m/s
dv: LLO to/from lunar = 1600 m/s; LLO to LEO using aerobraking = 700m/s source
extra mass of aerobraking shield and larger fuel tanks offset by elimination of ascent engine and shared structure, environment and power systems.

Calculations based on using LSAM engine:

Final mass to move LSAM from LLO to LEO using aerobraking = 12000*e^(700/3034) = 15114kg

Final mass to lift 15114kg from lunar surface to LLO = 15114*e^(1600/3034) = 25610kg

Final mass to move 25610kg from LLO to lunar surface = 25610*e^(1600/3034) = 43395kg

So approximately, a 43mt LSAM is required in LLO to land on the moon and return to LEO via LLO using 32mt of propellant

Now ESAS says: "The basic 1.5-launch EDS concept, S2B3/4/5, when coupled with LV 27.3, allows a 45 mT LSAM to be delivered with it to orbit"

Therefore it appears quite feasible to send a 12mt single stage LSAM with a LOX/CH4 engine and 32mt of fuel to the moon and return it to LEO using aerobraking. The predicted extra capacity of the CaLV is not even required! The LSAM performs the needed plane change during aerobraking to dock with the ISS in its 52° orbit.

The CEV would only be required to deliver crew to the EDS/LSAM in LEO (it should have sufficient fuel in its SM to change plane to the ISS to await use)

Advantages:
o Reduced risk through simplified architecture (no LOR, single stage single engine LSAM)
o Reduced LOC risk due to slower reentry from LEO
o CEV left in LEO (where it belongs)
o LSAM returned to LEO for inspection
o potential LSAM reuse
o Crew quarantine and checkout in LEO
o ISS utilization (it's about time)

gaetanomarano · 2006-05-31 08:52:20

...Calculations based on using LSAM engine...

I agree with you about the reusable LSAM but I don't see any advantage to send it to LEO after each mission

also if the CaLV/CLV payloads will be sufficient for your mission's architecture, it is a giant waste of propellant, that burns for nothing

I think that all reusable LSAMs must wait in lunar orbit (docked to a little assembly module) to be inspected/refueled there

the "big difference" is between earth and orbital maintence, not between earth-orbit and lunar-orbit maintenance

.

cIclops · 2006-05-31 09:12:05

...Calculations based on using LSAM engine...
I agree with you about the reusable LSAM but I don't see any advantage to send it to LEO after each mission
also if the CaLV/CLV payloads will be sufficient for your mission's architecture, it is a giant waste of propellant, that burns for nothing
I think that all reusable LSAMs must wait in lunar orbit (docked to a little assembly module) to be inspected/refueled there
the "big difference" is between earth and orbital maintence, not between earth-orbit and lunar-orbit maintenance
.

Yes more LOX/CH4 is burnt but look at the list of advantages, which of them is not worth a few tons of cheap propellant?

LLO orbit is unstable due to mascons, until Lunar fuel is available LEO is much cheaper too. A little LLO assembly module? There's another several billion dollars.

gaetanomarano · 2006-05-31 09:19:03

LLO orbit is unstable due to mascons, until Lunar fuel is available LEO is much cheaper too. A little LLO assembly module? There's another several billion dollars.

the lunar fuel must come from earth as "fuel-tanks-cartridges"

a little LLO assembly (and emergency) module can't cost more than an ISS' module and (like the ISS modules) will have a 10+ years life-cycle (with re-supply)

I think that (with or without the resuable-LSAM) an LLO module is ABSOLUTELY necessary to save the astronauts life if something goes wrong (and they must wait months for a rescue)

.

cIclops · 2006-05-31 09:37:59

I think that (with or without the resuable-LSAM) an LLO module is ABSOLUTELY necessary to save the astronauts life if something goes wrong (and they must wait months for a rescue).

Yes LOR is one of the main risks of the RTTM architecture, and that is why returning direct from the moon eliminates that risk completely.

gaetanomarano · 2006-05-31 09:43:16

I think that (with or without the resuable-LSAM) an LLO module is ABSOLUTELY necessary to save the astronauts life if something goes wrong (and they must wait months for a rescue).
Yes LOR is one of the main risks of the RTTM architecture, and that is why returning direct from the moon eliminates that risk completely.

if the engines don't work the only way to save the astronauts' life is a little emergency module in LLO since they can't use the extra life support sent on the moon and the LSAM ascent module is in its last hours of life...

.

New Mars Forums

Announcement

#1 2006-05-27 06:17:00

Re: Reusable LSAM

#2 2006-05-27 07:56:32

Re: Reusable LSAM

#3 2006-05-27 08:53:52

Re: Reusable LSAM

#4 2006-05-27 09:01:34

Re: Reusable LSAM

#5 2006-05-27 10:27:23

Re: Reusable LSAM

#6 2006-05-27 11:03:26

Re: Reusable LSAM

#7 2006-05-27 11:29:42

Re: Reusable LSAM

#8 2006-05-27 12:00:44

Re: Reusable LSAM

#9 2006-05-27 12:06:03

Re: Reusable LSAM

#10 2006-05-27 12:17:00

Re: Reusable LSAM

#11 2006-05-27 12:44:13

Re: Reusable LSAM

#12 2006-05-27 12:48:42

Re: Reusable LSAM

#13 2006-05-27 13:11:18

Re: Reusable LSAM

#14 2006-05-27 14:17:01

Re: Reusable LSAM

#15 2006-05-27 14:42:44

Re: Reusable LSAM

#16 2006-05-27 14:46:34

Re: Reusable LSAM

#17 2006-05-27 15:41:09

Re: Reusable LSAM

#18 2006-05-27 17:36:44

Re: Reusable LSAM

#19 2006-05-28 00:39:25

Re: Reusable LSAM

#20 2006-05-31 08:31:55

Re: Reusable LSAM

#21 2006-05-31 08:52:20

Re: Reusable LSAM

#22 2006-05-31 09:12:05

Re: Reusable LSAM

#23 2006-05-31 09:19:03

Re: Reusable LSAM

#24 2006-05-31 09:37:59

Re: Reusable LSAM

#25 2006-05-31 09:43:16

Re: Reusable LSAM

Board footer