Engine Pod Economics

Austin Stanley · 2006-05-17 04:23:47

I'm running some numbers on the the economics of a recoverable SSME pod for the CaLV. As we have disscused previously (and I think there is generaly agreement), the SSME is a viable alternative for the RS-68 as a first stage on the shuttle. It's performance is compariable (though its thrust is lower so you need more engines) and it has supperior relability. However, the key advantage of such pod is that it could conceivable be turned around and put into service for a relativly low price. When we compare the economics of such a pod with disposable engines over the 100 or so launches we might see in the service life of the CaLV, I think we will see that that it will provide a good return on the initialy high investment cost.

First we should analyse the cost of it's competition, namely the disposable cryogenic first stage of the CaLV with the RS-68 engines. The most signifigant item of this cost is the RS-68 engines which cost somewhere around $15 million a pop. The CaLV would use 3 of them, so we are looking at a $45 million in engines each launch. This is probably the single most costly item, but things like gimbles, control systems, power systems, ect are all wasted as well (and could be recovered in the engine pod). The costs for these items is not easily calculated, but likely is quite signifigant. But for simplicty of calculation, I'll assume they all weigh in at an even 5 million, giving us a totaly potential savings of $50 million a launch if we could turn the Engine pod around for free.

But how much would it actualy cost to turn the engine pod around? As I said before refurbishing the SSME engines is cheap, only a couple hundread thousand or so. Lets call it $200k. The CaLV would require 5 engines so that's a $1 million in engine refurbishment. There is also the cost of refurbishing the rest of the components, which isn't free either. Most signifigant is the heat-shield and recovery/parachute system the pod would require. These aren't free, and cost the shuttle a pretty penny. However, unlike the shuttle itself, the engine pod is only barely sub-orbital and so simple refurbishable heat-shield is a much more plausible option. Also, much of the fixed-recovery costs for the engine pod can be shared by the CEV which will require them as well. The shuttle can provide some, guide, and actualy it's incramental costs are quite low, around $55 million a launch. It's not unreasonable to assume that the much simpler engine pod (without OMS, RCS, and LSS to service) could cost 1/10 of that, it should weigh signifigantly less then 1/10 of the shuttles, but lets assume the costs is $10 million. This means the pod saves $40 million a launch, a not insignifigant sum.

The last figure to play with is how much the pod would cost to develop. The shuttle cost somewhere in the neighboorhood of $15 billion to develop and some 3-5 billion a copy. If we continue with the 1/10 figure we used for the incramental costs, plus a 100% fudge factor, we get a pod that would cost $3 Billion to develop and $1 billion per copy. Which seems reasonable. The SSME cost about a quarter of the cost of the entire vehicle, this is a much more concervative estimate than we gave for the RS-68 who's disposable componets came in at only 10% of the engine cost. If we go with 5 operational pods, this means the entire program will cost $8 billion dollars.

$8 billion seems like a lot, and it is, but lets go back to those RS-68 numbers and see how long it would take to pay it back. $8 Billion divided by the $40,000 million we save a launch means it takes 200 launches for the program to pay itself back. This is less then twice the number of shuttle missions we have launched, but considearbly fewer than the number of Soyuz launches. If we eliminate the fudge factor it pays for itself in fewer launches then the shuttle has seen. So taking the long view of it, an engine pod could certianly pay of.

Critiques welcome

gaetanomarano · 2006-05-17 05:57:13

.

reuse the engines is an excellent choice since engines are the main cost of a rocket

the idea was first developed by Boeing for a cargo version of the Shuttle (not the Shuttle-C)

when this option will be available many billions can be saved

its main problem is that needs very much R&D time and money to do it, especially for manned launches

if it needs (e.g.) 3+ years and $3+ billion, great part of the advantage is lost

I think the better way is...

- develop a rocket with expendable engines

- use it for early launches

- develop a new version with retrievable engines

- use the new version only for unmanned launches

- if it will be proven safe and reliable, use it also for manned launches

these are the reasons I've suggested to use expendable engines in my design of the FAST-SLV (despite its drawings suggests the use of a retrievable engines' basket)

.

cIclops · 2006-05-17 07:42:25

First we should analyse the cost of it's competition, namely the disposable cryogenic first stage of the CaLV with the RS-68 engines. The most signifigant item of this cost is the RS-68 engines which cost somewhere around $15 million a pop. The CaLV would use 3 of them, so we are looking at a $45 million in engines each launch.

The original CaLV design used 5 SSME engines so expect 5 RS-68s to replace them, this will surely change your costings.

Rxke · 2006-05-17 12:08:38

As I said before refurbishing the SSME engines is cheap, only a couple hundread thousand or so. Lets call it $200k. Where did you get the numbers saying refurbishment is approx 200 million?

I grew up when the shuttle was built, and have still clippings about how complex the SSMEs are, how much it cost to test them, when brand new...
Of course 20 years on, testing has obviously become cheaper etc. But exactly how cheap/expensive?

GCNRevenger · 2006-05-17 18:07:28

No no, I strongly oppose this idea!

This pod can't be a dumb heat shield with SSMEs on the back for a number of reasons...

First, it isn't "just barely suborbital," the whole stack sans SRBs reaches orbital altitude and ~80% of orbital velocity, so the only good way to recover the pod is for it to make an essentially complete orbit for a "once around" landing. This requires CEV-class thermal protection, independant power systems, and at least limited RCS/OMS with its associated hardware.

Second, this thing will be a nightmare to design, where you are having to cram ~40% more hardware into the capsule then Shuttle's cramped engine compartment holds, and you has to have fuel line and structural penitrations through the heat shield.

Third, its going to be big and heavy, the original CaLV design with the five SSMEs actually had the outer quartet of engine nozzles slightly outside the radius of the main tank, which means you are going to need to either compact this arrangement (expensive) to keep your heat shield around 8m wide, or else you'll need one 9m wide or so. Needless to say, expending one of these will be pricey indeed, the CEV heat shield is a bit over 20m square, while a 9m shield is over 65m square! All this added mass for shield and support hardware will ruin the CaLV's crucial payload capacity.

The pod itself will be of comparable complexity to the CEV itself I believe, which means a development cost around $6-7Bn and a construction cost for a half dozen units would put this near the $10Bn mark. Remember, the original price tag for Shuttle construction is in 1970s/80s money, and the engine compartment was probably the hardest thing to build on the whole orbiter.

And just what do we gain? We have to fly it two hundred times to see any return on the investment? No way! We will only be flying a few CaLVs a year for the Lunar program and only a half a dozen or so anually for both Moon and Mars missions, it would take at least twenty years to realize any savings if it were only a hundred flights if we fly an average of 4.5 times a year.

And what of the development time and risk? We have an engine that works just fine right now today, no development, no risk, just copy the RS-68 from the Delta-IV and put it on the bottom of the tank. The RS-68 has most of its support hardware built in unlike SSME, so designing the rest of the engine compartment will be easy and it will be cheap and light weight.

NASA needs the CaLV on time, on budget, and not befall serious delays. The SSME pod will save almost no money and is high risk to endangering both Lunar and Mars programs if its development doesn't go smoothly, which is the rule and not the exception for Shuttle. It just makes no sense NOT to use RS-68!

And thats assuming it works. If it is not highly reliable, then you will simply run out of pods and not have any margin for losing more, with a rocket that has to use those engines, which probably haven't been made in years after the initial run of pods...

...and then what?

Austin Stanley · 2006-05-17 19:52:53

A lot to reply to here, so bear with me.

The original CaLV design used 5 SSME engines so expect 5 RS-68s to replace them, this will surely change your costings.

The RS-68 produces more thrust than the SSME, so you only need three of them to do the same job. However, the two engines have similar ISP (the SSME is slightly supperior) and thrust to weight ratios (I think the RS-68 is slighlty supperior). Of course going with 5 SSME gives you an engine out ability an a minor increase in payload (though the engine pod would eat all that up and more).

I grew up when the shuttle was built, and have still clippings about how complex the SSMEs are, how much it cost to test them, when brand new...
Of course 20 years on, testing has obviously become cheaper etc. But exactly how cheap/expensive?

The recent IIA block of the SSME and new space shuttle main engine processing facility hae brought the costs down signifigantly. And the incramental costs involved in flying the shuttle have always been pretty low. If we assue that thing such as the Stenice Space Center and the SSMEPF are going to remain open servicing diffrent bits of our new infastructure (which I do) the additional incramental costs is all we have to pay. And I got that figure from the simple 1/10 of what it costs the shuttle to do the same thing guestimation :-)

This pod can't be a dumb heat shield with SSMEs on the back for a number of reasons...
First, it isn't "just barely suborbital," the whole stack sans SRBs reaches orbital altitude and ~80% of orbital velocity, so the only good way to recover the pod is for it to make an essentially complete orbit for a "once around" landing. This requires CEV-class thermal protection, independant power systems, and at least limited RCS/OMS with its associated hardware.

If it can't quite make a full-orbit that it is sub-orbital right? The key cost saving diffrence here is that if it doesn't achive orbital velocity it wouldn't require a OMS for a circulisation burn. And if it's heat shield is self righting (which a good capsle style design should be) it wouldn't require a RMS either. It simply falls back to earth on it's ballistic trajectory, which (if we play are cards right) would bring it back down for a soft touch down somewhere over Texas. The engine pod can be set on this trajectory before seperation, while the EDS can reconfigure for it's own trajectory during it's insertion and circulisation burns. As for a power-system, the podless CaLV is going to require this as well, only it has to through this away and doesn't get to recover it. Or is the entire first stage going to be powered and controled by the (also disposed of) Earth Departure Stage?

This is a good place to note the the pod could share many of the same or similar system as the CEV, such as the semi-reusible heat shield it is supposed to have. Also, by going for a once-around soft touch down we can eliminate the recovery fleet and share our landing system development with the CEV as well.

Second, this thing will be a nightmare to design, where you are having to cram ~40% more hardware into the capsule then Shuttle's cramped engine compartment holds, and you has to have fuel line and structural penitrations through the heat shield.

No rocket is easy to design, but aside from technical challanges with the heat-shield I see no show stopping reason why it couldn't be designed. Unlike the shuttles engine compartment it will not have to make room for the Bulky OMS and their fuel.

Third, its going to be big and heavy, the original CaLV design with the five SSMEs actually had the outer quartet of engine nozzles slightly outside the radius of the main tank, which means you are going to need to either compact this arrangement (expensive) to keep your heat shield around 8m wide, or else you'll need one 9m wide or so. Needless to say, expending one of these will be pricey indeed, the CEV heat shield is a bit over 20m square, while a 9m shield is over 65m square! All this added mass for shield and support hardware will ruin the CaLV's crucial payload capacity.

As I said earlier, the pod can share some of it's heat-shield design with the CEV, which (last I heard) is planed to be semi-reusable. So the heat-shield would not be expended every mission.

I have no arguments against the comments about it's weight. It will be heavier then the pod-less design and will diminish the CaLV payload somewhat. However, switching to the SSME gives a slight increase in performance, which offsets this somewhat. Switching to the proposed chemical flyback boosters could also help make up the diffrence.

The pod itself will be of comparable complexity to the CEV itself I believe, which means a development cost around $6-7Bn and a construction cost for a half dozen units would put this near the $10Bn mark. Remember, the original price tag for Shuttle construction is in 1970s/80s money, and the engine compartment was probably the hardest thing to build on the whole orbiter.

Well the engines themselves were probably the single most expensive item, but that development cost has already been paid for. Next probably comes the thermal protective system, which the pod can share costs with the CEV with. Likewise with it's recovery system. However, unlike the CEV or the orbiter, the pod has to deal with keeping people alive for long periods in space or signifigant orbital manuvers in space. So if we compare the simpler engine pod to the CEV my 8 Billion dollar estimate is again rather concervative. As the pod mass at most half as much as the CEV, expecting the program to cost half of the 15 billion alocated to the CEV is not unreasonable.

And just what do we gain? We have to fly it two hundred times to see any return on the investment? No way! We will only be flying a few CaLVs a year for the Lunar program and only a half a dozen or so anually for both Moon and Mars missions, it would take at least twenty years to realize any savings if it were only a hundred flights if we fly an average of 4.5 times a year.

We have to take a long range view on space vehicle development. The shuttle has been with us for over 20 years now (longer if we go from the first date of first conception), and we a still looking at using it into the next decade. I hope the CaLV proves to have as succesfull a career as the Shuttle does. Or better yet, if we could be more like the Soyuz, that would be even more development. When we have vehicles that are going to be around for that length of time, it only makes sense to evaluate their costs over that length of time as well. Also hopefully once we have a 100MT launcher with low-incremental costs to put things into orbit we will start launching them more often. The CaLV/CLV combo is ideal for building and maintaining a space stations as well as the Mars/Moon missions, and of course the more cargo we put on the Moon/Mars (which wouldn't necessarily require a CLV launch) the better as well.

And what of the development time and risk? We have an engine that works just fine right now today, no development, no risk, just copy the RS-68 from the Delta-IV and put it on the bottom of the tank. The RS-68 has most of its support hardware built in unlike SSME, so designing the rest of the engine compartment will be easy and it will be cheap and light weight.

It's not fair to assume that the RS-68 has no additional design cost associated with it. The shuttles tank is going to have to be modified to accomidate it, and new power, control, and gimbles systems will likely have to be designed as well. Certianly the pod would cost more to develop, but the RS-68 isn't free either.

NASA needs the CaLV on time, on budget, and not befall serious delays. The SSME pod will save almost no money and is high risk to endangering both Lunar and Mars programs if its development doesn't go smoothly, which is the rule and not the exception for Shuttle. It just makes no sense NOT to use RS-68!

Here we see the benifit of an expendable rocket design program. We could build the CaLV with the RS-68 now and develop the SSME pod later. Since the CaLV is all disposable anways, nothing is lost by going with this approach.

And thats assuming it works. If it is not highly reliable, then you will simply run out of pods and not have any margin for losing more, with a rocket that has to use those engines, which probably haven't been made in years after the initial run of pods...

Well there are no guarantees in life, much less space travel. But we have every reason to belive it would be more reliable. The SSME is already one of (if not THE) most reliable engines in existance. Going with 5-SSME adds engine out ability to the CaLV, which again increases reliability. The pod's heat shield also will see extensive testing via the CEV before it is ever launched.

SpaceNut · 2006-05-17 20:29:09

Engine look ok at low altitude but the rs68's are not as good the higher up you go losing efficency and require more fuel to achieve the same goal.

A miss conception I think of what sub orbital means in that most feel the near space condition of roughly 60 miles is sub orbital but I see your point of not entering orbit as close.

Before the engine compartment can come back the tank must be jetisoned from it, which adds a layer of difficulty.

I do not think that the pod would self orient since the heaviest part will tend to face towards the earth upon reentry. I believe this would mean that the engines would see the heat of reentry and would begin to tumble as the atmospher hits them.

Engines do not like landing in the ocean and will add to the cost depending on how long they are in the water before recovery occurs.

GCNRevenger · 2006-05-17 23:05:34

Here are the two options and their configurations NASA has considerd for the CaLV:

-Use standard 8.4m tankage with five SSMEs
-Use bigger 10m tankage with five RS-68s

Apparently, the heavier boosters alone weren't enough to bring the payload up to the desired 125MT line when the J-2X was selected for the upper stage, or at least Griffin wanted engine-out capacity. The RS-68's lower Isp is more important then a few seconds difference seems, and it is really intended to trade cheaper higher-thrust engines for bigger (and relativly less expensive) tanks. Both configurations would have engine-out capacity and essentially identical payloads. NASA can't switch back-and-forth, they have to settle on one design or the other, the different diameters means too much trouble later on to redesign the rocket, so an SSME pod can't be a future upgrade.

"The key cost saving diffrence here is that if it doesn't achive orbital velocity... if it's heat shield is self righting (which a good capsle style design should be) it wouldn't require a RMS either. It simply falls back to earth on it's ballistic trajectory"

I don't think it will work, it doesn't quite reach full orbital velocity, but 80% of it is enough to require a heat shield of similar quality. Given the flat shape the shield would require I doubt it would be self-righting.

"the pod could share many of the same or similar system as the CEV, such as the semi-reusible heat shield it is supposed to have"

It really wouldn't. The capsule for the engines will be so much bigger then the CEV, that it couldn't be common between them, the CEV shield is under 1/3rd the size. You might use the same material for the heat shield, but otherwise they would be totally different. Particularly since the pod will require penitrations for structure and fuel lines. It will require lots of testing too I imagine.

"Unlike the shuttles engine compartment it will not have to make room for the Bulky OMS and their fuel"

Hmmm? The Shuttle engine compartment doesn't, the OMS pods contain all the fuel and support hardware for them external of the compartment.

"It will be heavier then the pod-less design and will diminish the CaLV payload somewhat. However, switching to the SSME gives a slight increase in performance, which offsets this somewhat. Switching to the proposed chemical flyback boosters could also help make up the diffrence."

The CEV weighs in around 6MT, and the pod will probably weigh about double that not counting the engines themselves, which is a hefty ~10% payload penalty. Since the RS-68 version of the CaLV will have a wider diameter, there will be no difference between non-pod SSME and RS-68 payloads. Liquid boosters would be nice, but I doubt that ones of sufficent scale will be on the drawing board for decades.

"unlike the CEV or the orbiter, the pod has to deal with keeping people alive for long periods in space or signifigant orbital manuvers in space. So if we compare the simpler engine pod to the CEV my 8 Billion dollar estimate is again rather concervative. As the pod mass at most half as much as the CEV, expecting the program to cost half of the 15 billion alocated to the CEV is not unreasonable"

Each SSME weighs a little over three tonnes, so the whole pod will weigh far more then the CEV will. Even if you disreguard the engines, the simple size of the structure/heat shield and support hardware will weigh double I guesstimate. The sheer mass of the pod will probably mean the CEV's parachutes/airbags would be insufficent for the pod too. The pod will be little simpler then the CEV capsule either. Having limited attitude control is not much less complicated then having a high degree of control, SSME requires fairly complex avionics, plus the external hydraulic systems for gimbaling/valves plus the power supply.

"It's not fair to assume that the RS-68 has no additional design cost associated with it."

Why not? What needs to be changed? The RS-68 is largely self-contained with onboard hydraulics/gimbals, and the power (perhaps avionics too) systems can be copied from Delta-IV since they aren't reuseable. What is so much different about the CaLV compared to the hind end of a Delta?

GCNRevenger · 2006-05-17 23:08:16

Then there is the fact that I don't think is sufficently emphasized, that because of the commonality with Shuttle's engine compartment, that the systems are proven to be prone to the cost getting out of control. The EELVs have done a better job in this respect. Anyway, I think a figure of $10Bn for development and construction of several units is probably closer to accurate.

"We have to take a long range view on space vehicle development"

No, we really don't, infact, the short-term is all important! NASA has run out of credibility, that it will either suceed with this task or probably be dismanteld. If it costs a few billion out of the half-trillion-dollar VSE to decrease development time, cost and risk then its a good deal. Development costs today are more important then saving a little money tomorrow.

"it only makes sense to evaluate their costs over that length of time as well"

Heavy lift rockets are efficient, but they will never be efficient enough to do more then small-scale exploration or research "camps" to the Moon and Mars (maaaybe visit Jupiter) is as far as they can take us. I can't see NASA ever needing more then 200 copies of the CaLV, that should be plenty to get a foothold on the Moon and Mars. That will take up to 40yrs from now, so its a good figure for the "life" of the basic design before NASA needs something better.

Assuming the pod saves aproximatly $125M per flight but costs $10Bn to develop/build, that is a savings of only $15Bn, a mere 2.3% of the total NASA budget if funding remains constant. This is assuming that the cost of the RS-68 stays around $15M a copy, but if NASA is buying ~23 of them a year instead of Delta only needing a few, the cost each could be considerably lower, further eroding the the miniscule bennefit of the pod. With a production of 25-30 units anually, say NASA could save $3M each, then the RS-68 version of the CaLV just got $3Bn cheaper over its operational life. This is roughly the best-case senario with a large sum of money saved per-flight and a large number of total launches.

Again, it is worth the cost to have a rocket with less risk, cost, and development time; $12-15Bn may sound like alot of money, but it really isn't in the long run, just 2% and this is best-case, actual savings could be half that. Trading possible future savings for ~$10Bn cheaper development and greatly reduced technical risk is a good deal.

Edit: I picked $125M per-flight if the pod is able to save $75M worth of engines plus ~$50M of support hardware and amoratizing expanding the CaLV's diameter over 200 flights. In hindsight I think this figure is kind of high, but I didn't want to change the figures in my post. Instead I will list a "worst case" senario for the pod: if the RS-68 costs $12M a copy and $25M versus enlarging the CaLV tank. Say that turn-around costs would largely eat up savings from reusing support hardware... In this case the pod only saves ~$85M a flight, and say NASA only launches CaLV 150 times. This yeilds a savings of only $2.75Bn, or only 0.4% of the total 40-year budget.

cIclops · 2006-05-18 09:09:54

In this case the pod only saves ~$85M a flight, and NASA only launches CaLV 150 times. This yeilds a savings of only $2.75Bn, or only 0.4% of the total 40-year budget.

$85,000,000 * 150 = $12.75 B

Ten billion here, ten billion there and soon you're talking a real Mars programme

Grypd · 2006-05-18 09:48:11

But it does not though compare when the economies of scale are used.

A SDV heavy lifter using a pod will have to wait for that pod to be refitted and then flight verified before it can be used again. Since there are a limited amount of pods if we need to ramp up the launches then it will be impossible with pod technology. In short we have a set price and it will not drastically change even with advances in technology.

But the more we use an SDV heavy lifter the more that are made when expendable then the cheaper it gets. There is less need for flight verified and there will be less concern over wear and of course these launchers will have a greater cargo launch capacity.

And the savings leading to a Mars mission is wrong that money saved from a launch will be spent elsewhere. It will not go to a bank account for a future Mars Mission. Actually much more likely is it will be spent on testing sea soaked rockets to ensure they launch correctly.

So no savings and delayed launches regulary

GCNRevenger · 2006-05-18 10:38:35

In this case the pod only saves ~$85M a flight, and NASA only launches CaLV 150 times. This yeilds a savings of only $2.75Bn, or only 0.4% of the total 40-year budget.
$85,000,000 * 150 = $12.75 B
Ten billion here, ten billion there and soon you're talking a real Mars programme

Minus the $10Bn it costs to develop and build the pods of course.

Austin Stanley · 2006-05-18 15:30:17

Again, alot for me to respond to.

Before the engine compartment can come back the tank must be jetisoned from it, which adds a layer of difficulty.

We've been doing stage seperation for a long time, so I don't expect this to cause any undue difficulty. In particularly this seperation occurs out on the edge of space and after the engines have stopped firing (but before the EDS seperates). My only worry is ensuring that the tank and the pod seperate far enough that they don't interfere with one another during re-entery.

I do not think that the pod would self orient since the heaviest part will tend to face towards the earth upon reentry. I believe this would mean that the engines would see the heat of reentry and would begin to tumble as the atmospher hits them.

A mater of design, the center of gravity must be set such that the heat-shield end of the pod goes in first, not the engine end. Not necessarily as difficult as it might seem, as only the engines bells realy extend out from where we probably need the center of gravity to be. The heavy gimbles and turbo-pumps as well as the power and control systems are all situated more towards the heat shield end.

Engines do not like landing in the ocean and will add to the cost depending on how long they are in the water before recovery occurs.

I agree landing the SSME in the ocean would be a bad thing. Which is why they would mostly likely be recovered over land like the CEV is planned to, and like the Soyuz always have been.

Here are the two options and their configurations NASA has considerd for the CaLV:
-Use standard 8.4m tankage with five SSMEs
-Use bigger 10m tankage with five RS-68s
Apparently, the heavier boosters alone weren't enough to bring the payload up to the desired 125MT line when the J-2X was selected for the upper stage, or at least Griffin wanted engine-out capacity. The RS-68's lower Isp is more important then a few seconds difference seems, and it is really intended to trade cheaper higher-thrust engines for bigger (and relativly less expensive) tanks. Both configurations would have engine-out capacity and essentially identical payloads. NASA can't switch back-and-forth, they have to settle on one design or the other, the different diameters means too much trouble later on to redesign the rocket, so an SSME pod can't be a future upgrade.

No reasons they can't switch back and forth at all. The tanks, secound stage, and every thing else (besides perhapce the SRB) burn up after the mission, they are not recovered at all. The only cost associated is in the design and building new dies (if necessary). It's not like going with 10m tankage prevents the return to 8.4m tankage, nor is it a given that the SSME pod could not be utilised with the 10m tankage either. The extra fuel would help counter the extra mass of the pod, and we might even end up with some extra to spend on payload.

I don't think it will work, it doesn't quite reach full orbital velocity, but 80% of it is enough to require a heat shield of similar quality. Given the flat shape the shield would require I doubt it would be self-righting.

The thermal protective system will have to be substantial, this is true. But my main point is that OMS/RCS are absolutly not required, as the pod can be set on an apropriate balistic path before seperation. Nor is the heat-shield requied to be flat. A biconic heat shield, similar to that used on the DC-X (or would have been used) makes the most sense to me. This would also alow some manuverability during re-entery.

"the pod could share many of the same or similar system as the CEV, such as the semi-reusible heat shield it is supposed to have"
It really wouldn't. The capsule for the engines will be so much bigger then the CEV, that it couldn't be common between them, the CEV shield is under 1/3rd the size. You might use the same material for the heat shield, but otherwise they would be totally different. Particularly since the pod will require penitrations for structure and fuel lines. It will require lots of testing too I imagine.

Even if it only shares the same material, that is still alot of design cost saved, as formulating a semi-reusable heat-shield material will not be cheap I imagine.

"Unlike the shuttles engine compartment it will not have to make room for the Bulky OMS and their fuel"
Hmmm? The Shuttle engine compartment doesn't, the OMS pods contain all the fuel and support hardware for them external of the compartment.

I confess I am no expert on shuttle design, but aren't the OMS the two small engines above and two the left and right of the shuttles engines? How are these not part of the engine compartment? In any case comparisions to the shuttles engine compartment are rather useless as the pod and it will share little design similiarities.

"It will be heavier then the pod-less design and will diminish the CaLV payload somewhat. However, switching to the SSME gives a slight increase in performance, which offsets this somewhat. Switching to the proposed chemical flyback boosters could also help make up the diffrence."
The CEV weighs in around 6MT, and the pod will probably weigh about double that not counting the engines themselves, which is a hefty ~10% payload penalty. Since the RS-68 version of the CaLV will have a wider diameter, there will be no difference between non-pod SSME and RS-68 payloads. Liquid boosters would be nice, but I doubt that ones of sufficent scale will be on the drawing board for decades.

Hmm? I guess how you measure the mass of the CEV depends alot upon exactly what components you look at. But I still don't see where you get the 6MT figure from. What I have seen (at astronautix has the crew module coming in at ~9MT, the service module at ~6MT dry, and the whole thing when fueld some ~22MT (dependant upon the mission of course). In any case, any payload penalty that results from the pods weight could be made up for (to an extent) with more fuel tankage or bigger more powerful SRB. Specificly I am talking about the liquid fueld flyback replacments for the SRB which have been on the drawing board for years.

"unlike the CEV or the orbiter, the pod has to deal with keeping people alive for long periods in space or signifigant orbital manuvers in space. So if we compare the simpler engine pod to the CEV my 8 Billion dollar estimate is again rather concervative. As the pod mass at most half as much as the CEV, expecting the program to cost half of the 15 billion alocated to the CEV is not unreasonable"
Each SSME weighs a little over three tonnes, so the whole pod will weigh far more then the CEV will. Even if you disreguard the engines, the simple size of the structure/heat shield and support hardware will weigh double I guesstimate. The sheer mass of the pod will probably mean the CEV's parachutes/airbags would be insufficent for the pod too. The pod will be little simpler then the CEV capsule either. Having limited attitude control is not much less complicated then having a high degree of control, SSME requires fairly complex avionics, plus the external hydraulic systems for gimbaling/valves plus the power supply.

As I said before, I think the CEV with all it's components masses considerably more than you think it does, the pod would certianly mass less then half of the 22MT the CEV does, (minus the engines). The parachutes and airbags would have to be scaled up for recovery, but this is haredly a daunting design issue. As for the rest of it systems, it should be obvious how much simpler the pod is versus the CEV. It doesn't have to keep people alive for days at a time, it doesn't have to manuver in outer space, it's power system only has to be good for a couple of hours rather than days, ect... In the places where it is complex, the CEV is two having it's own engine, recovery, and thermal protective systems. And the pod has the advantage of not having to redesign it's engines for it's task.

"It's not fair to assume that the RS-68 has no additional design cost associated with it."
Why not? What needs to be changed? The RS-68 is largely self-contained with onboard hydraulics/gimbals, and the power (perhaps avionics too) systems can be copied from Delta-IV since they aren't reuseable. What is so much different about the CaLV compared to the hind end of a Delta?

Besides the obvious re-design of the Shuttle Main Tank, the Delta-IV (in any configuartion) does not mount 3 RS-68 next to each other they way they will be in the CaLV, nor does it provide for engine-out abilities. But my main point is that the design of the CaLV with the RS-68 isn't free, it's not like you can just take some RS-68s slap them under the SMT, and call it a rocket.

Then there is the fact that I don't think is sufficently emphasized, that because of the commonality with Shuttle's engine compartment, that the systems are proven to be prone to the cost getting out of control. The EELVs have done a better job in this respect. Anyway, I think a figure of $10Bn for development and construction of several units is probably closer to accurate.

The key diffrence bettwen the pod and the shuttle's engine compartment is again, that the most expensive part (the engines) have already been designed. The complicated issues dealing with fuel/oxidiser rounting and the like have also already been solved. Cost control is more a matter of managment then it specific to design in any case. It's not like using the SSME magicaly makes this a problem or using the RS-68 magicaly solves it. But 10Bn or 8Bn were are in the same ballpark in terms of program cost.

"We have to take a long range view on space vehicle development"
No, we really don't, infact, the short-term is all important! NASA has run out of credibility, that it will either suceed with this task or probably be dismanteld. If it costs a few billion out of the half-trillion-dollar VSE to decrease development time, cost and risk then its a good deal. Development costs today are more important then saving a little money tomorrow.

Which is why I like using expendable designs now, and switching to the pod later. You can have your cake and eat it to. I think your fears are overblown as well. The NASA program is far to large and important part of both our economy and our national pride to ever be cancled out-right despite the many mistakes they might make. Simply put, the powerful senators and congresspersons in Texas and Florida will never let this happen.

"it only makes sense to evaluate their costs over that length of time as well"
Heavy lift rockets are efficient, but they will never be efficient enough to do more then small-scale exploration or research "camps" to the Moon and Mars (maaaybe visit Jupiter) is as far as they can take us. I can't see NASA ever needing more then 200 copies of the CaLV, that should be plenty to get a foothold on the Moon and Mars. That will take up to 40yrs from now, so its a good figure for the "life" of the basic design before NASA needs something better.

Unless and untill we develop some other cheaper method of delivering 100ton cargos into space in one shot there will continue to be a place for HLLV generaly and the CaLV specificly. I'm all for things like SSTO, TSTO spaceplanes, and space-elevators, but realisticly speaking it will quite some time before they are ready to take the place of the HLLV. So it makes sense to develope a HLLV that can do it's job as efficently as possible so as we (hopefully) begin to scale our heavy-lift program up to meet our commitments on Moon/Mars/beyond the cost begin to come down as well.

Assuming the pod saves aproximatly $125M per flight but costs $10Bn to develop/build, that is a savings of only $15Bn, a mere 2.3% of the total NASA budget if funding remains constant. This is assuming that the cost of the RS-68 stays around $15M a copy, but if NASA is buying ~23 of them a year instead of Delta only needing a few, the cost each could be considerably lower, further eroding the the miniscule bennefit of the pod. With a production of 25-30 units anually, say NASA could save $3M each, then the RS-68 version of the CaLV just got $3Bn cheaper over its operational life. This is roughly the best-case senario with a large sum of money saved per-flight and a large number of total launches.
Again, it is worth the cost to have a rocket with less risk, cost, and development time; $12-15Bn may sound like alot of money, but it really isn't in the long run, just 2% and this is best-case, actual savings could be half that. Trading possible future savings for ~$10Bn cheaper development and greatly reduced technical risk is a good deal.
Edit: I picked $125M per-flight if the pod is able to save $75M worth of engines plus ~$50M of support hardware and amoratizing expanding the CaLV's diameter over 200 flights. In hindsight I think this figure is kind of high, but I didn't want to change the figures in my post. Instead I will list a "worst case" senario for the pod: if the RS-68 costs $12M a copy and $25M versus enlarging the CaLV tank. Say that turn-around costs would largely eat up savings from reusing support hardware... In this case the pod only saves ~$85M a flight, and say NASA only launches CaLV 150 times. This yeilds a savings of only $2.75Bn, or only 0.4% of the total 40-year budget.

I won't argue with your figures as they are generaly more optimistic than mine. However saving 2 billion dollars is still quite a big deal. That 2 billion could pay for an extra mars mission, R&D for some other fancy toy, or some other space-goody. But when we take the long range look at it, some other factors become important as well.

#1. We can generaly expect NASA's budget to go up, not down, in the future. This has generaly always been the case. The space-program gets more money now (in real dollars) then it did in the past, more than even in the apollo days I belive. This is only logical as the US economy (and goverment budget) continue to grow and percentage spending on space is likely to either remain constant or grow as well. This will especialy be true if our missions on the Moon and Mars are succesfull and popular, and our competitors (like China) continue to keep the pressure on us.

#2. Hopefully as the budget grows, our missions in space will grow as well. We can expect the number of missions for the CaLV to grow with time. Which would result in more savings. To an extent this is already planned. Our mission on the moon shouldn't stop when we launch our mission on Mars, which means we will be launching twice as many CaLV to support them both. The need for heavy lift will only go up from there as we begin to develop perminate bases on both bodies and begin to expand our exploration even further outward.

But it does not though compare when the economies of scale are used.
A SDV heavy lifter using a pod will have to wait for that pod to be refitted and then flight verified before it can be used again. Since there are a limited amount of pods if we need to ramp up the launches then it will be impossible with pod technology. In short we have a set price and it will not drastically change even with advances in technology.

I disagree, the 8bn number I quote and the 10bn number GCRN quotes both include a small stable of pods (about half a dozen) to do the launches with. Even if the turn around times were realitivly long (6 months or so, longer then the shuttle in most cases) this would give us a large enough fleet to launch a dozen or so CaLV's a year which is quite a bit more than we currently plan on launching (but fewer then I hope we one day will be). Even if the pod can only do as well as the shuttle, despite being much simpler, it will still be sufficent.

But the more we use an SDV heavy lifter the more that are made when expendable then the cheaper it gets. There is less need for flight verified and there will be less concern over wear and of course these launchers will have a greater cargo launch capacity.

It is true to an extent that as we ramp up CaLV production we will get some discounts due to economies of scale and mass production, however there is a limit to this. As the high-tech materials used in the CaLV's production are a signifigant portion of it's cost. Mass production can only save on the labor, not the materials.

However for the Pod we can save on both ends. Since we recover the matrials we do not have to pay for them again (or the labor to re-manufacture them). The economies of scale and the discount they provide in labor can also be applied to the refurbishment of the pod as well. In particularly the incramental costs for launching the shuttle are very low, around $55 million a launch. The pod, being much simpler should cost much less (I estimated $10 million). As the number of launches scales up the pod with it's slightly higher fixed costs (shared partialy with the CEV) and much lower incramental costs will be the clear winner.

And the savings leading to a Mars mission is wrong that money saved from a launch will be spent elsewhere. It will not go to a bank account for a future Mars Mission. Actually much more likely is it will be spent on testing sea soaked rockets to ensure they launch correctly.

The pod would be recovered over land, saving on both sea-soaked-rocket testing and the recovery vessles. Otherwise I am unsure exactly what you are arguing. Of course the money saved will be spent elseware. Has saving money suddenly become a bad thing?

cIclops · 2006-05-18 15:41:07

[
... re savings
Minus the $10Bn it costs to develop and build the pods of course.

Ah yes, okay.

Given the 30% development costing margin that Griffin now makes NASA use, there is a significant risk that a $3B overspend would exceed the estimated $2.75 B saving. Add to that the complexity of the pod, which in turn means higher risk to the vehicle and launch schedule; not to mention (but I will) the draining of precious development funds and increased risk to the development schedule. IMHO it's an "all round bad idea" (tm).

GCNRevenger · 2006-05-18 22:48:01

The RS-68 and SSME version of the rocket really aren't interchangeable; the SSME with its lower thrust would suffer gravitational losses with the 10m tank and reduce payload. Each engine was designed to be paired with a given mass of propellant, with the RS-68 conciously being made to trade specific impulse for big cheap fuel tanks. As a result, RS-68 has 80% less parts but 50% more thrust and costs a third as much. You would have to go back to the narrower diameter and change back all the construction and launch hardware to the older size. Also, both engines might not be readily available, the SSME line might be closed for a long time if NASA goes with RS-68 now, and conversely the RS-68 line might be closed if the USAF "down selects" Delta without NASA buying engines. Restarting either line would be expensive.

You can't have your cake without penalty or risk

"But my main point is that OMS/RCS are absolutly not required, as the pod can be set on an apropriate balistic path before seperation. Nor is the heat-shield requied to be flat. A biconic heat shield"

I don't agree. Some attitude control will still probably be nessesarry without a high degree of self-righting capability, which will not be easy with a relativly flat shield. And it does have to be fairly flat, there is no room for the "point" of a biconic shield that gives it this advantage, plus a biconic shield has a much larger area then a disk shaped one and would lead to excessive payload penalties.

"As I said before, I think the CEV with all it's components masses considerably more than you think it does, the pod would certianly mass less then half of the 22MT the CEV does, (minus the engines). The parachutes and airbags would have to be scaled up for recovery, but this is haredly a daunting design issue. As for the rest of it systems, it should be obvious how much simpler the pod is versus the CEV"

I was referring to the capsule only and not the whole vehicle, and it seems I have confused the masses of the capsule and the service module. No matter... the SSMEs will weigh 16MT by themselves, and their support hardware several more tonnes, which is adding up to be a pretty hefty capsule, especially if it has a biconic heat shield. 10-15MT+ perhaps not counting the SSMEs and their hardware. I have doubts that the landing systems could be scaled up sufficently without difficulty, and the payload penalty will be fairly large.

Anyway, I strongly disagree that the pod will be simpler then the CEV capsule, the support hardware required for five SSMEs will be of similar complexity to the power/LSS of CEV, and the fuel line/structural heat shield penitrations required add substantial complexity to the design too. And it will also probably need attitude control too. It will not be any simpler then the CEV capsule.

Flyback/recoverable liquid boosters would be nice, but they can't be part of the consideration over what design today's CaLV will take. Without them, the mass of the pod will really impact the performance, but NASA has neither the time nor the money to build these boosters at the moment. NASA needs CaLV cheap and fast with maximum payload to sucessfully build a Lunar base, and sacrificing either of these for liquid boosters isn't happening.

"it's not like you can just take some RS-68s slap them under the SMT, and call it a rocket"

But really, why not? If three engines on seperate stages can operate in close proximity to concert, five should be able to work just fine on the bottom of the CaLV. Really, what does need to be modified? Engine-out capability is largely a matter of software, and need not be very complex beyond "engine 2 stopped firing, shut off engine 4 and throttle up 1,3, & 5."

GCNRevenger · 2006-05-18 23:53:26

While I don't believe that NASA would ever outright be closed down, I don't think that a future any of us except Jeff Bell wants is a sure thing. Texas and Florida don't care where NASA flies to, as long as they keep flying. It is quite possible that NASA will be restricted to "science" missions in LEO for a long long time if they fail to make credible progress with VSE on time and on budget. If they fail to do this, then its quite likly that someone will trade Texas and Florida something else for a big NASA budget cut. Already, $1.6Bn of NASA funding was considerd for cuts to pay for police subsidies recently.

I am also skeptical about NASA's budget being raised as the economy strengthens, or at the least the portion of NASA's budget that is available to spend on launch vehicles will not differ greatly. If NASA is told to do something in addition to the VSE plan, then it will probably be an expensive something and they may not get much extra money to spend on launch vehicles. Also, if it seems to congress that NASA is doing okay with VSE on $16.5Bn a year, why would congress give them lots more money? I think we should assume that NASA's effective budget with reguard to launch vehicles will not increase much over the life of the VSE plan.

What determines the worth of the engine pod is how much it saves per flight and how many times it will launched: how many times is NASA going to fly the CaLV? Assuming NASA goes through with the ESAS plan and something like DRM-III for Mars then each Lunar mission will expend one and each Mars vehicle will take two with three vehicle required per mission. To man bases on either body continuously, two Lunar sorties per year and one Mars sortie every other year would be required. To build/tend a base, lets increase the demand by one additional sortie per year to the Moon and one every year other to Mars.

Lets say that it will take 40 years from now to execute the VSE plan and build both bases; assuming we operate a Lunar base concurrently with a Mars base and Mars missions start 20 years from now, that will mean we will need 164 copies of CaLV (24 from now to 2026, 140 from 2026 to 2046). In the event that we want to keep using CaLV longer then 2046 this figure could be higher, or if Lunar crew/cargo were farmed out to private interests and the DRM-III plan made semi-reuseable it could be lower (use ERV as cycler, build reuseable Mars-fueled MAV).

I think a range of +/- 35 units is really the edge of reason. An extra 35 units would take us to 2051, at this point NASA's budget should be pretty heavily strained just maintaining both bases, and they won't have enough money to do alot else. I think this is end of the line for the CaLV, and either a much less expensive rocket would be built from scratch with then-new technology, or a true RLV built.

Reuseing my cost figures from my last post, with $10Bn for development and construction of the pod, and for reference NASA's total budget is $660Bn over 40yrs at $16.5Bn/yr.

-Best case senario, SSME pod replaces $75M of RS-68 engines, $25M of support hardware, and $25M to widen the tank for a total of $125M saved.

-Worst case senario, bulk orders of RS-68 reduced to $60M a flight and essentially no savings on reusing support hardware due to refurbishing costs, saving $85M a flight.

129 flights - best $6.0Bn, worst $1.0Bn
164 flights - best $10.5Bn, worst $4.0Bn
199 flights - best $15.0Bn, worst $7.0Bn

So if everything went really well, NASA would save $15Bn over a very long time, but if it doesn't go well NASA will only save a few billion at most... Also, this savings will only be realized as small annual sums over many years, and not as a big lump sum over a few years needed for a development program or even an additional Mars mission, but if only a few billion is saved as in "worst case" then this savings will be impreceptable.

I believe there is also a risk that congress, seeing this "extra money" going unused, will simply take this money and spend it on something else, or perhaps the non-VSE wings of NASA will sucessfully lobby for a small annual raise. NASA is not a bank, and its ability to store up cash is limited by external and internal political realities.

GCNRevenger · 2006-05-19 00:05:02

Last post of the evening, short I promise...

The situation as I see it, is that congress has little faith in NASA in light of the last 25 years of failure, but they don't want to close the agency down and spin off the science/aviation wings. Therefore, they would probably be happy to let NASA fool with the ISS and later its sucessor on a smaller scope for decades and redistribute a large chunk of NASA's budget elsewhere.

NASA, and hopes of manned flight beyond the Earth, therefore rest on the VSE plan, as they are running on borrowed credibility and time. Congress will support NASA if VSE suceeds, but doom them if it fails. Therefore, it is of great importance that it not fail, very great importance, and choices made should reflect that VSE sucess really is crucial.

The hardest part of VSE is probably getting started. NASA will need to show results sometime within the next five to ten years I would imagine before that borrowed time will run out. Since this partially coincides with continued flights of Shuttle with its cost and monopolizing KSC, NASA must absolutely minimize development cost and time for the VSE launch vehicles.

Avoiding the SSME pod is an excelent example of this, that NASA would be trading lower development risk, cost, and time for the future possibility of slightly reduced annual costs, the majority of which won't be seen for thirty years. This makes excelent sense, and infact makes so much sense that it is foolish to do otherwise.

The SSME pod in light of the limited bennefit to the VSE plan, as ciclops put it, a bad idea.

gaetanomarano · 2006-05-19 05:04:53

.

build a recoverable-engines-pod is NOT a bad idea (it was, first, developed by Boeing for a possible cargo-Shuttle)

but, of course, it is a technology that needs time and money to become safe and reliable

now, the best way is to use expendable engines for the CaLV (or SLV or FAST-SLV or DDHLV or something else)

the ("final"...) choice of NASA is the RS-68 (recent news) that costs $20M each

the expendable version of the SSME costs $40M each (recent news)

but, since the SSME is reusable, it was never built in many units

I think that, also the SSME, may cost less that $40M if it will be built in dozens units

however, the recoverable-engines-pod technology (that, now, is not the cheaper way to build a rocket) may be useful in future if space agencies or privates will build rockets bigger than CaLV (like a super-cargo rocket to build big space stations) and with many engines

.

GCNRevenger · 2006-05-19 07:07:03

Whether the SSME pod is a good idea or a bad idea is a matter of context, since the sole purpose of the pod is to save money by reusing engines, then the merit of the pod depends on how much you save versus expendable options.

In the case of Boeing's reuseable engine pod, that was proposed a long time ago, well before the introduction of the uber-cheap RS-68 engine. No other large cryogenic engine was available when the Boeing pod was proposed, but now there is, and since the RS-68 is so cheap the pod doesn't save much money.

And yes, developing the pod will take time and money, two things that NASA is in short supply of. Already the ~2018 date to return to the Moon is largely controlled by the development of the CaLV, and pushing this date further into the future for cost or technical reasons would sorely hurt NASA's already tarnished credibility.

RS-68 is reported to cost about $15M each, and I bet if NASA were buying 10-30+ of them a year, that each unit would be a little cheaper, say 20% for about $12M each. SSME on the other hand, sells for about $45M each, and if it recieved the same 20% bulk discount (which I think is generous, given how complex the engine is) still costs $36M each, still tripple RS-68.

The only economical way to use the SSME for the CaLV is in the fasion it was intended for, and thats reuseability.

I don't think there will be a rocket bigger the CaLV, infact I think there will be a demand for a lighter heavy lifter in the 100MT range later on. The NASA DRM-III plan calls for a pair of launchers with ~90MT of capacity to build each Mars vehicle, one for the HAB/MAV/ERV and one for the nuclear powerd transit stage. The big 125MT CaLV could lift a larger chemical stage (just a stretched EDS perhaps) instead of a nuclear one, and thats as big as I can see NASA needing.

publiusr · 2006-05-19 12:19:05

Whether the SSME pod is a good idea or a bad idea is a matter of context, since the sole purpose of the pod is to save money by reusing engines, then the merit of the pod depends on how much you save versus expendable options.

A pod is something we really don't need. And it would just waste time. Zubrin's concept came before the advent of RS-68s.

Use RS-68s and be done with it.

I will praise Zubrin and Gaetano for supporting CaLV, and we need more pro-HLLV voices out there, regardless.

Martin_Tristar · 2006-05-20 06:44:15

We need to design the vehicles to be part of a larger recycling program for the whole space timeline when we move into space on a permanent basis. We need to recycle engine assemblies, fuel storage tansk and more, for the expansion of space. It could be used in unmanned transport tugs or drone vehicles or even lunar cargo tugs, It doesn't mean it, just launch systems.

We are going into space, in a bit way moving out from earth into our solar system. We need to develop robotic / automated systems that could build the necessary infrastructure for humans to expand into that planet or moon or asteroid.

GCNRevenger · 2006-05-20 07:14:31

Blah blah blah science fiction all

We absolutely do not need to recycle anything, especially not fuel tanks, nor are robots up to the task of building anything on their own. Our technology is just not that advanced yet, it is not yet time for Buck Rodgers or 2001: SO.

SpaceNut · 2006-05-20 21:04:02

Back to topic of can we and should we forgo the cost to develope a reusable engine pod. Knowing that it will land in water means a total teardown after each use. The shuttles engine do not land in water and they still are under a million to refurb. Have posted this 96 shuttle reference before in that it breaks down which facility gets what with this regards.

Martin_Tristar · 2006-05-21 07:34:11

GCNR, Mr Money Bags !!!!!!!!

If we don't recycle and build vessels including drone / automated vehicles with recycled or reused components from previous launches then it will cost more money and resources then any one country has to offer and could afford. The first spacefaring nation or organization that develops their space program on a large recycle program will win the space race even on a smaller budget.

So, Mr Money Bags, If you want to get charged for parts that can be reused including the engines particular they could be reused in space then we should look at those proposals. Also we have the technology ( both Hardware and software ) to launch and build a moonbase or marsbase with automated vehicles using gaming methodology and rule based logic systems. I think you don't see all the advances in technology at the hardware and software platforms that could be adapted to the space environment and function nicely.

I do think we could use automated systems to setup a small outpost landing for humans to arrive on Mars and could have the gardens and other systems running before any humans have landed and when the humans land the environment is set for life. So , think before you type, Mr Money Bags. (AKA GCNRevenger)

cIclops · 2006-05-21 07:51:03

If we don't recycle and build vessels including drone / automated vehicles with recycled or reused components from previous launches then it will cost more money and resources then any one country has to offer and could afford. The first spacefaring nation or organization that develops their space program on a large recycle program will win the space race even on a smaller budget.

And if we do, we won't have an exploration programme for a long long time. All previous attempts to make RLVs have been abandoned due to cost and unreliablity. All new launcher designs are at best only partly reusuable. Obviously it's desirable to achive full reuse as with air, ground and sea vehicles, but it is beyond current technology. RLVs are very very hard to do. NASA spent more than $100 billion trying to make reusuable vehicles and the Soviets also spent an enormous amount. Both agencies, and AFAIK all others have no plans to build RLVs.

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