WI: (Mostly) Wingless Shuttle

LostCosmonaut

Based on my memory, as well as some documents I've read (http://www.dtic.mil/dtic/tr/fulltext/u2/729770.pdf), the STS had a large crossrange requirement from early in the program. This was due to various Air Force requirements, one of which was to be able to return to the launch site after one orbit. Having such a large wing area naturally increases mass, causes all sorts of issues (such as needing a heavier launch vehicle). Additionally, since the wing is going to have a sharp leading edge, you're going to see greatly increased thermal loading in those areas.

Suppose the excessively large crossrange requirement is ditched early in the STS program. Having some maneuvering capability is still desirable. In my opinion, a pure lifting body design, along the lines of the X-24 or L-301 would be a suitable shape. With the wings deleted, you can either use the saved mass to stick the STS on a smaller launch vehicle (and potentially eliminate having a parallel-staged stack), increase the payload capability, or build a more robust vehicle. As a result, I feel that ditching the wings is a good idea. How do y'all feel?
 

Dathi THorfinnsson

LostCosmonaut said:
Based on my memory, as well as some documents I've read (http://www.dtic.mil/dtic/tr/fulltext/u2/729770.pdf), the STS had a large crossrange requirement from early in the program. This was due to various Air Force requirements, one of which was to be able to return to the launch site after one orbit. Having such a large wing area naturally increases mass, causes all sorts of issues (such as needing a heavier launch vehicle). Additionally, since the wing is going to have a sharp leading edge, you're going to see greatly increased thermal loading in those areas.

Suppose the excessively large crossrange requirement is ditched early in the STS program. Having some maneuvering capability is still desirable. In my opinion, a pure lifting body design, along the lines of the X-24 or L-301 would be a suitable shape. With the wings deleted, you can either use the saved mass to stick the STS on a smaller launch vehicle (and potentially eliminate having a parallel-staged stack), increase the payload capability, or build a more robust vehicle. As a result, I feel that ditching the wings is a good idea. How do y'all feel?
Click to expand...
Basically, the Shuttle was driven by Air Force requirements - which were accepted to get Air Force support for the Shuttle, which NASA figured they needed, as the project was so expensive.

Of course, the Air Force changes (both the wings/cross range capability, and the increased payload (size and mass)) made the Shuttle even more expensive, and less cost-effective. (as in, not cost effective compared to expendables).

So. Your PoD could be NASA not trying to involve the Air Force at all. Of course, maybe the whole project gets shut down due to overruns without Air Force support,....

<rant>NASA's biggest problem is that they were too successful. The Saturn/Apollo project pushed tech massively, and it all worked, with only a few minor bugs. This made NASA think they could do anything. Which made them too ambitious and the result was the Shuttle.</rant>
 
Michel Van

Michel Van

There were several Wingless aka Lifting Body proposal for space shuttle
also with extend wings.

USAF had harsh demands on Cross range glide to landing site, what fit for Lifting body perfect.
on other side NASA had demands for landing speed of Orbiter
last one is problem of Lifting Body is that need high landing speed over 236 miles per hour
under that speed, a Lifting Body fly dangerous unstable
the OTL orbiter lands with 214 to 226 miles per hour
 

e of pi

Avoiding having the wings doesn't really help a lot if you're still throwing away the whole stack below it. For a crew ferry, it can be a bitbetter from a cost perspective than a fully-expendable stack, but you really don't win by reusing just the crew vehicle and launching on a slightly smaller stack. If you want to cut the cost of the stack...reuse the stack! The first and second stages are the most serious cost centers, and thus they're what you really want to reuse--especially as long as you're throwing a crew/cargo vehicle as large as Shuttle.
 

Delta Force

Banned
I'm wondering if it would have been possible to build a 1.5 stage heavy lift vehicle using 1960s or 1970s technology. The original Atlas rockets were able to do it on a smaller scale, but they also had unusual features such as load bearing fuel and oxidizer tanks.

Essentially, this idea would involve using a massive fuel tank as the core "stage" of the rocket. It would have pods akin to liquid rocket boosters attached to it, containing the engines and any related equipment that could be recovered for later use. Fuel loads and the number of engine modules could vary according to mission, providing flexibility. It would be similar to Energia, but instead of a rocket core there is simply a large disposable fuel tank.
 

e of pi

Kevin Renner said:
I can't find it now but wasn't there a shuttle proposal that used three vehicles with the same shape in which two were used as boosters with the third being the orbiter. All three were reusable and orizontal landing. A UK project I think. Ah, yes
http://www.airforce-technology.com/...ard-fighter-jet-bae-forgotten-aircraft-4.html
Click to expand...
Others also messed around with the idea, as with the Convair Trimese shuttle studies, as well as two-stage designs with specially tailored (and more efficient) booster/orbiters. Sadly, all these were lost when Shuttle funding was cut too low to allow...well, basically any reuse of any of the stack (the SRBs hardly count, given they have to be nearly totally re-manufactured).
 

Delta Force

Banned
Kevin Renner said:
I can't find it now but wasn't there a shuttle proposal that used three vehicles with the same shape in which two were used as boosters with the third being the orbiter. All three were reusable and orizontal landing. A UK project I think. Ah, yes
http://www.airforce-technology.com/...ard-fighter-jet-bae-forgotten-aircraft-4.html
Click to expand...

The United Kingdom designed a complicated spaceplane system, but never designed a capsule, mini-shuttle, or an SLV capsule of carrying people and two tons or more of payload to low Earth orbit?

e of pi said:
Others also messed around with the idea, as with the Convair Trimese shuttle studies, as well as two-stage designs with specially tailored (and more efficient) booster/orbiters. Sadly, all these were lost when Shuttle funding was cut too low to allow...well, basically any reuse of any of the stack (the SRBs hardly count, given they have to be nearly totally re-manufactured).
Click to expand...

What about 1.5 stage heavy lift designs? Could costs have been brought down if the focus was on retrieving components with the highest value to mass/volume ratios that can be overhauled without too much expense?

Also, why did NASA bother to recover the SRBs if they had to be mostly remanufactured anyways?
 

Crowbar Six

The United Kingdom designed a complicated spaceplane system, but never designed a capsule, mini-shuttle, or an SLV capsule of carrying people and two tons or more of payload to low Earth orbit
Click to expand...

I remember seeing a BAE proposal on Tomorrows World for a reusable 10 man capsule in the 80's which went nowhere. The idea was it could be used for cargo and personnel deliveries to one of the proposed space stations (Freedom I think), it would reduce the need for so many shuttle launches and it would use smaller boosters to save cash. It could also be configured with some additional hardware as a low cost orbital lab by adding various modules. I have looked for data on this periodically over the years but can't find any, if my brother hadn't remembered it I would think it was my imagination. I suspect it was one of those back of a fag packet designs which every design group come up with which is then handed over to the art department to give them something to do.
 

e of pi

Delta Force said:
The United Kingdom designed a complicated spaceplane system, but never designed a capsule, mini-shuttle, or an SLV capsule of carrying people and two tons or more of payload to low Earth orbit?
Click to expand...
They didn't do a lot of work on it, as far as I can tell. Mostly a paper project. And as Crowbar Six is vaguely recalling, they actually did do some capsule studies (though later), as a suggested alternative to Hermes for ESA--mostly on the eventually-proven-correct grounds that Hermes was too heavy and complex.

What about 1.5 stage heavy lift designs? Could costs have been brought down if the focus was on retrieving components with the highest value to mass/volume ratios that can be overhauled without too much expense?
Click to expand...
You could do a 1.5 stage design that could throw a substantial payload--what you're describing sounds a lot like the "Saturn 1D" stage-and-a-half design, but with recovery of the engine booster ring (essentially, the mods I did to it in the Caelus design I designed for Brainbin's TWR thread). It's really only a toss-up on cost--since you throw a lower fraction of your initial liftoff mass to orbit than a full two-stage design would, you end up needing more rocket to throw the same payload, and a lot of that (the sustainer engine and the tanks) ends up in LEO where it's hard to get them back--and any recovery hardware you do add to the sustainer eats directly into payload. It can probably be fudged into being break-even with an expendable two-stage LV, but it's beaten by a true reusable first stage paired with a smaller, expendable upper stage like F9R is on its way to being or (especially) by a
fully reusable two-stage rocket.
Also, why did NASA bother to recover the SRBs if they had to be mostly remanufactured anyways?
Click to expand...
A few reasons at a few times. At the start, in the design phase, it was thought it would be easier and cheaper than it eventually turned out to be. Once they were flying, it was still cheaper by a hair or two cheaper, just not nearly as much as they'd thought or enough to make up for the costs of Shuttle refurb or throwing away the external tanks. Finally, Shuttle was never really subjected to cost-benefit analysis once it was flying--there was never funding for a Shuttle Mk2, and it was the program of record, so most changes made once it was flying were incremental ones aimed at safety (booster mods after Challenger, for instance) or increasing payload (the Light-Weight Tank and Super-Light-Weight Tank mods to increase payload to higher/more inclined orbits like ISS).
 
Last edited:

Delta Force

Banned
e of pi said:
They didn't do a lot of work on it, as far as I can tell. Mostly a paper project. And as Crowbar Six is vaguely recalling, they actually did do some capsule studies (though later), as a suggested alternative to Hermes for ESA--mostly on the eventually-proven-correct grounds that Hermes was too heavy and complex.
Click to expand...

Ironic that the United Kingdom hasn't had much of a manned space program - or much of a space program in general - despite having several prominent space proponents and organizations such as the British Interplanetary Society.

You could do a 1.5 stage design that could throw a substantial payload--what you're describing sounds a lot like the "Saturn 1D" stage-and-a-half design, but with recovery of the engine booster ring (essentially, the mods I did to it in the Caelus design I designed for Brainbin's TWR thread). It's really only a toss-up on cost--since you throw a lower fraction of your initial liftoff mass to orbit than a full two-stage design would, you end up needing more rocket to throw the same payload, and a lot of that (the sustainer engine and the tanks) ends up in LEO where it's hard to get them back--and any recovery hardware you do add to the sustainer eats directly into payload. It can probably be fudged into being break-even with an expendable two-stage LV, but it's beaten by a true reusable first stage paired with a smaller, expendable upper stage like F9R is on its way to being or (especially) by a fully reusable two-stage rocket.
Click to expand...

It seems that unless an SSTO design can be built, a 1.5 stage design would be the most practical approach to a reusable vehicle. Unless a means of recovering upper engines can be developed that doesn't reduce payload too much, something is always going to be lost in the process. It would probably be easier to recover the half stage of engines on a 1.5 stage design than to recover the engines and fuel tank from the lower stage of a 2 stage design.

For example, an S-IC stage weighs 298,104 pounds (135,128 kilograms) empty, but would certainly weigh more with recovery equipment and some unspent fuel and oxidizer on board. Each F1 engine weighs 18,498 pounds (8,391 kilograms) each, a total of 92,490 pounds (41,955 kilograms). That's about a third the empty weight of the stage, and because it's concentrated it can be provided with a heat shield to allow reentry from higher space.
 
Michel Van

Michel Van

Delta Force said:
The United Kingdom designed a complicated spaceplane system, but never designed a capsule, mini-shuttle, or an SLV capsule of carrying people and two tons or more of payload to low Earth orbit?
Click to expand...

the British design and Study allot of Capsules, Spaceplanes and Lifting Bodys
like MUSTARD the britisch version of the Convair Trimese shuttle studies,
RAF even look into licensing agreement for MOL and Gemini Hardware.
BAC even proposed in 1969 a British low cost shuttle with solid booster and a drop tank !
But British politic had other problems and strenuous ignore those proposals

For Moment they try SKYLON spaceplane / SSTO
 

e of pi

Delta Force said:
It seems that unless an SSTO design can be built, a 1.5 stage design would be the most practical approach to a reusable vehicle. Unless a means of recovering upper engines can be developed that doesn't reduce payload too much, something is always going to be lost in the process. It would probably be easier to recover the half stage of engines on a 1.5 stage design than to recover the engines and fuel tank from the lower stage of a 2 stage design.
Click to expand...
Not at all necessarily the case on a couple fronts, I think. First, as far as recovering an entire first stage vs the booster ring of some kind of stage-and-a-half Saturn, the first stage's tanks do add a bit more mass to recover--but they also add a lot of surface area, and room for either lifting devices like wings (for flyback) or tank volume for boostback F9R-style. As F9R demonstrates, one need not add too much mass to a first stage to recover it--the legs and TPS on the first stage are under 2 metric tons to recover almost 19 tons of the stage, though that doesn't quite account for the prop required. On the other hand, a booster ring can basically only get away with parachutes and airbags at best--meaning you have to go pluck them out of midair before they can hit the water, or deal with saltwater immersion. Thus, I'd argue that recovering an entire first stage is at worst equal to the task of recovering a booster ring, and may actually be easier.

As far as whether a stage-and-a-half design is superior to a fully or partially reusable first stage design, Akin's First Law is that engineering is done with numbers, so I've tried to whip some examples.

First, a cost analysis of a stage-and-a-half design. The basic masses are from the back of an envelope and Astronautix data, while the cost-per-kg numbers for the hardware are even more rough, but should be within the ballpark. I compute, over on the far right, a $/kg for an integrated stage with these values--I use this through the rest of the examples, so any issues with these $/kg numbers should follow.

Second was a quick TSTO LV using these assumptions--kerolox lower, hydrolox upper. Not the most optimal, but all within the ballpark. As you can see, its payload $/kg is comparable to the stage-and-a-half design--it's throwing away a bit of hardware the other design doesn't, but it needs only about a third the liftoff mass--835 tons instead of the 2,000+ of the Saturn 1D stage-and-a-half.

Third, a first-stage-only RLV. I'm modeling a boostback first stage here, so I've bumped the first stage's dry mass fraction from 7% to 9% to account for reusability hardware and I'm forcing it to do about 1.5 km/s of boostback burns (other slowing down can be done aerodynamically, this is roughly in line with planned F9R burn magnitudes as far as I know). As you can see, it's about half the cost of either of the above LVs--and again, recovering the first stage like this need not be more complex than recovering the booster ring of the stage-and-a-half.

Finally, a fully reusable TSTO RLV. I bumped the upper stage's dry mass from 0.10 to 0.15--orbit is harder, so I added a lot of expected heat shield mass. The nice thing, of course, is that it takes much less of a burn to do deorbit than boostback, which almost balances things out--time your deorbit right, and you'll drop right onto your launch site, no need for massive burns to get back to it. Cost here is the victor over the others by a vast margin--less than 15% of either the fully-expendable or the stage-and-a-half.
 

Delta Force

Banned
The problem with recovering a complete lower stage is that it would require automated systems or remote control, or a crew member on board to glide the stage to a landing site. Automation would be difficult even now due to the complexity involved, and a Space Shuttle era design likely would have difficulty achieving enough accuracy to land on a runway. A person could do the job, but they would have to be provided with some means of escaping a failing rocket, which would be more difficult given that they would be seated somewhere in that stage. Also, the person who performs that role would essentially undergo the same training and experience many of the same dangers as an astronaut, but wouldn't actually get to go into space. Finding people to fill the return pilot role could be difficult.

Also, I don't think the reusable designs have refurbishment costs taken into account. Depending on how high those are, it might be cheaper to go with a 2 stage design, or perhaps a 1.5 stage design. It would depend on how much it would cost to have factories for producing both rocket stages and likely two engine families at a high rate of production, versus having factories for producing a high volume of tanks and a low volume of engines and a refurbishment facility. Of course, since an upper stage engine is being lost every flight, the 1.5 stage design could potentially reduce costs by using engines capable of a lower number of flight hours, either through design simplifications to reduce costs or by uprating the engines.

Lastly, what about half staging on larger rockets (2.5 stage designs)? I don't see why the S-ID approach couldn't be used on the lower stages of rockets with two or more stages. If supported by a program using a smaller 1.5 or 2.5 stage rocket with J-2 engines, the larger rocket could use engines nearing the end of their usable lifespan.

I suppose this idea is a bit different from typical reusability ideas, but it focuses on one of the most expensive parts of the rocket. It should be easier to refurbish engines and a heat shield for another flight instead of an entire rocket system.
 

e of pi

Delta Force said:
The problem with recovering a complete lower stage is that it would require automated systems or remote control, or a crew member on board to glide the stage to a landing site. Automation would be difficult even now due to the complexity involved, and a Space Shuttle era design likely would have difficulty achieving enough accuracy to land on a runway.
Click to expand...
Reasonably sophisticated automation was a thing even in the 70s--I mean, an ICBM had to guide itself to within a very small target zone through atmospheric entry, and a returning stage could expect the benefit of radio beacons or the like on the ground to assist. It's certainly possible now completely autonomously (see Grasshopper, DC-X, and the X-34). Less possible with 70s-era tech, but maybe still doable. Of course:

A person could do the job, but they would have to be provided with some means of escaping a failing rocket, which would be more difficult given that they would be seated somewhere in that stage. Also, the person who performs that role would essentially undergo the same training and experience many of the same dangers as an astronaut, but wouldn't actually get to go into space. Finding people to fill the return pilot role could be difficult.
Click to expand...
There were in-era designs that had pilots aboard--the TSTO fully-reusable shuttles, for instance, all pictured a flight crew aboard (and these pilots would naturally rotate with orbital-bound astronauts, the same way pilots rotate through CapCom and liaison to manufacturers). It's a complication, but it's not an impossible one or even a particularly challenging one. We're not talking that far beyond the flight profiles of, say, the X-15.

Also, I don't think the reusable designs have refurbishment costs taken into account. Depending on how high those are, it might be cheaper to go with a 2 stage design, or perhaps a 1.5 stage design. It would depend on how much it would cost to have factories for producing both rocket stages and likely two engine families at a high rate of production, versus having factories for producing a high volume of tanks and a low volume of engines and a refurbishment facility. Of course, since an upper stage engine is being lost every flight, the 1.5 stage design could potentially reduce costs by using engines capable of a lower number of flight hours, either through design simplifications to reduce costs or by uprating the engines.
Click to expand...
The model does take into account refurbishment costs here in a very simplistic way--the full name of "# of flights" is "# of flights before the refurb costs are equal to the original construction costs". ;) I have fancier models that actually estimate those refurb costs and allow separate values for , but I didn't have access to them when I put that sheet together. If you're curious, I just changed it from 30 to 10, and the results are:

1.5 Stage: $6,329/kg
Fully expendable: $5,692/kg
First stage Reusable: $3,079/kg
Fully Reusable: $1,811/kg

And again with it dropped to just 5:
1.5 Stage: $7,014/kg
Fully expendable: $5,692/kg
First stage Reusable: $3,641/kg
Fully Reusable: $3,358/kg

It doesn't change that TSTO with first-stage reuse beats stage-and-a-half with engine reuse or that fully-reusable TSTO beats everything else, but it does change the margins--and actually mean that partially-reusable stage-and-a-half starts losing out to even fully-expendable TSTO.

Lastly, what about half staging on larger rockets (2.5 stage designs)? I don't see why the S-ID approach couldn't be used on the lower stages of rockets with two or more stages. If supported by a program using a smaller 1.5 or 2.5 stage rocket with J-2 engines, the larger rocket could use engines nearing the end of their usable lifespan.
Click to expand...
That's basically what the plan was for the Saturn 1D--read up on Saturn V-B and V-C. Cost reduction there is minimal, but it offers a bit of payload improvement.
 

LostCosmonaut

e of pi said:
Not at all necessarily the case on a couple fronts, I think. First, as far as recovering an entire first stage vs the booster ring of some kind of stage-and-a-half Saturn, the first stage's tanks do add a bit more mass to recover--but they also add a lot of surface area, and room for either lifting devices like wings (for flyback) or tank volume for boostback F9R-style. As F9R demonstrates, one need not add too much mass to a first stage to recover it--the legs and TPS on the first stage are under 2 metric tons to recover almost 19 tons of the stage, though that doesn't quite account for the prop required. On the other hand, a booster ring can basically only get away with parachutes and airbags at best--meaning you have to go pluck them out of midair before they can hit the water, or deal with saltwater immersion. Thus, I'd argue that recovering an entire first stage is at worst equal to the task of recovering a booster ring, and may actually be easier.

As far as whether a stage-and-a-half design is superior to a fully or partially reusable first stage design, Akin's First Law is that engineering is done with numbers, so I've tried to whip some examples.

First, a cost analysis of a stage-and-a-half design. The basic masses are from the back of an envelope and Astronautix data, while the cost-per-kg numbers for the hardware are even more rough, but should be within the ballpark. I compute, over on the far right, a $/kg for an integrated stage with these values--I use this through the rest of the examples, so any issues with these $/kg numbers should follow.

Second was a quick TSTO LV using these assumptions--kerolox lower, hydrolox upper. Not the most optimal, but all within the ballpark. As you can see, its payload $/kg is comparable to the stage-and-a-half design--it's throwing away a bit of hardware the other design doesn't, but it needs only about a third the liftoff mass--835 tons instead of the 2,000+ of the Saturn 1D stage-and-a-half.

Third, a first-stage-only RLV. I'm modeling a boostback first stage here, so I've bumped the first stage's dry mass fraction from 7% to 9% to account for reusability hardware and I'm forcing it to do about 1.5 km/s of boostback burns (other slowing down can be done aerodynamically, this is roughly in line with planned F9R burn magnitudes as far as I know). As you can see, it's about half the cost of either of the above LVs--and again, recovering the first stage like this need not be more complex than recovering the booster ring of the stage-and-a-half.

Finally, a fully reusable TSTO RLV. I bumped the upper stage's dry mass from 0.10 to 0.15--orbit is harder, so I added a lot of expected heat shield mass. The nice thing, of course, is that it takes much less of a burn to do deorbit than boostback, which almost balances things out--time your deorbit right, and you'll drop right onto your launch site, no need for massive burns to get back to it. Cost here is the victor over the others by a vast margin--less than 15% of either the fully-expendable or the stage-and-a-half.
Click to expand...

Thanks for the excellent analysis. I'd somewhat suspected that two stage designs would be best on cost, but it's nice to see actual numbers.

On a related note, how do you feel about this SSTO concept?
 

e of pi

LostCosmonaut said:
On a related note, how do you feel about this SSTO concept?
Click to expand...
It's interesting in regards to composite tanks, but I see a couple concerns:

1) It's an expendable SSTO, not an RLV. There's not a lot of benefit in expendable SSTO except ground ops--and even then it's not a big one compared to the hit to payload fraction. Using their same structural design, a two-stage expendable would have about 6-7% GLOW as payload, not 2%--that means either triple the payload for the same liftoff mass or only needing a vehicle a third the size. Considering the challenges inherent in a nanosat launcher anyway (the small scale means aerodynamics and control system masses start to matter a lot more than in larger launchers), that's not trivial.

2) They seem to handwave the engine pretty heavily. The engine's a pretty substantial fraction of their structural mass, yet none of the engines they cite as examples offer the required T/W ratio by their own admission. They try to cite the improved ISp of those engines as making up for it, but I am lead to wonder why they didn't just iterate the design with a feasible baseline engine with more realistic T/W and ISp. This isn't exactly a 500-page study where they couldn't just update whatever Excel doc they did the calculations in and re-run the numbers. It makes me wonder about their structural design a bit when the engines are so understudied.
 
You must log in or register to reply here.
Top
Top