Author Topic: What would a better STS Have Looked Like?  (Read 31810 times)

Online Lobo

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Re: What would a better STS Have Looked Like?
« Reply #30 on: 04/04/2012 06:02 PM »
If I were to choose a new design for the shuttle with I'd use the McDonnell Douglas concept as a starting point.
Though I'd change a few things such as the first stage would be hydrocarbon vs hydrogen fueled.

Yes,
I agree.  If I had to choose a winged orbiter today, and maximum reusability was a program driver (as opposed to cheaper  expendibles.  IN which case I still like my triple 6m F-1A core design)  this seems like a much better plan.  RP-1 is better for a booster obviously, than LH2.  Your booster would be smaller too, with the denser RP-1.  Not to mention you reduce your foam/ice issues by not having that big LH2 tank to worry about.  Maybe they could have modified the S-IC (heavily modified), probably slimming it down and making it longer, but using some of the same systems, including the F-1A engines. 
After booster separation (which youd want to stage low enough that the booster can fly back and land), you could either build an LH2 system into the Orbiter, with say, a J2S engine, for a fully reusable system.  (although thatd cut into your usable payload volume of the orbiter).  Or design a disposable upper stage thatd mount on the rear of the orbiter and be air-lit as a 2nd stage that would get it to a disposal orbit (so the on-board OMS could do the circ burn like STS) or do the circ burn too, and have ullage motors which would dispose of the stage.
I imagine the latter would be best, so the orbiter itself would have enough usable volume to be similar to shuttle, and not need an even larger TPS.  Maybe use a modified S-IVB or larger Centaur stage?

Of course, this concept can be used with a large capsule too.  Then you dont have to worry about all the drawbacks to wings before landing.  Be easier to mount a disposable upper stage on too.

Makes you wonder why this design wasnt chosen in the 1970s?
« Last Edit: 04/04/2012 06:19 PM by Lobo »

Online Lobo

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Re: What would a better STS Have Looked Like?
« Reply #31 on: 04/04/2012 06:13 PM »
Well, I think a reusable, large capsule would be fairly easy to do.  Its an efficient and simple design, and easy to make robust without adding a lot of mass, unlike a space plane.  A large version of the Gemini or Dragon capsule, except with all the features of the Shuttle cabin, plus an integral, internally stowed manipulator arm.  I think Orion is around 8mt, so Id think you could do something like that for 20mt.  Give it a very strong and well fueled RCS/OMS system so that it can maneuver itself and large payloads and act as a tractor/tug.  With a wall angle closer to Dragon than Apollo, the LAS/landing engines could act like SMME/OMS engines.  It would need to be designed to have enough fuel for OMS maneuvers, as well as land.
I like that too.  Basically a F-X heavy and dragon 2.  Picturing a dragon 2 as using methane also though, and with a taller mould line (for when long "umbrella" satellites are in it).  Crew version would seat 25 or so.  But I would rather see this bypassed for a reusable F-XX heavy and "really big" dragon 2 combo.  ;)

http://forum.nasaspaceflight.com/index.php?topic=21981.msg682814#msg682814  There's a big debate in this thread about capsule vs. wings for larger sized stuff.  The link pretty much arrives at the opening salvo.     



Well, there wasnt an FX for FXX concept back in the 1970s era were we are setting this hypothetical.   We already had an FXX so to speak, with Saturn V, and the powers that be decided they didnt want that.  I already have a thread about if the Saturn V hadnt been canceled, what we might have today?  Almost heartbreaking to think about the possibilities.  It would have been refined, lightened, streamlined, and make cheaper and more efficient over time, just as all of our ELVs have been with the advent of automation and CAD in the interim years.

http://forum.nasaspaceflight.com/index.php?topic=26667.0

This thread is about Saturn V still being cancelled, and a semi-reusable system needed to be designed and built no matter what.  How could we have done it better?

Something more along the FX or AVP2 size.  Then you can use the booster cores by themselves, or use them together to launch an orbiter or other heavy load. 
If FXX is desired, they could have just restarted the Saturn V line for that.

Offline Ronsmytheiii

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Re: What would a better STS Have Looked Like?
« Reply #32 on: 04/04/2012 10:45 PM »
This would have been the ultimate shuttle (in concept)

Now let me get out of here before Jim starts throwing things  ;D

Offline Fequalsma

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Re: What would a better STS Have Looked Like?
« Reply #33 on: 04/05/2012 01:30 AM »
IIRC, one of the early Shuttle program managers (Thompson?) said that selection of the expendable ET was the key decision that allowed the design to close.  And I don't think that they were all that expensive, are they?  Maybe $50M each?  Less than 10 percent of each launch.
F=ma


IMO, Shuttle was probably hurt more by the decision to use an ET than anything else. It was the longest lead time and most expensive item. Even if every other system had worked flawlessly, ET's would have limited the flight rate to 24 per year.


Online Lobo

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Re: What would a better STS Have Looked Like?
« Reply #34 on: 04/06/2012 05:47 PM »
This would have been the ultimate shuttle (in concept)

Now let me get out of here before Jim starts throwing things  ;D

VentureStar was pretty sweet in concept.  Just wondering if it every had actually been built and flown, and even if it operated properly, would it have suffered the issues the Shuttle did, but even several fold worse.  As in overhead costs?  I know the plan was for it to have been cheaper to mainain between flights than the Shuttle, but When the Shuttle was developed, I think it was projected to only need like a team of 100 techs, a few weeks to have it ready for launch again.  But it ended up being thousands of techs and months for a best case turn around.
Seems VentureStar would have been even more complex, than the most complex piece of machinery in the world was already, the shuttle.  YOu had a much larger surface area exposed to damage in LEO, and a much larger surface exposed to the extremes of reentry.  Seems those things would in reality necessitate a LOT more on ground process than originally thought (just as the Shuttle did), and wouldn't surprise me if significantly more than the Shuttle.

I think possibly for a replacement Shuttle, maybe combining Venturestar with the Old McDonnald-Douglas concept.  Then your orbiter could be much smaller, but all of your components could be reused.  Could even get clever with it, and have that stack take off from a runway like Venturestar was planned to, rather than like a rocket like the MD concept.  The carrier craft could be designed to add enough lift to the stack to get it off the runway, but it could have more traditional shape and construction LH2 tanks, rather than whatever new stuff Venturestar required.  Basically, just a big LH2/LOX tank with wings and landing gear.
The carrier craft would have higher-thrust engines like RS-68's to get the stack going from the ground.  THe Orbiter would have something more like J2S, or RL-60's.  It would have enough onboard propellant storage to get from the limit of the carrier craft to orbit.  But that'd be far less than Venturestar would need.  So it wouldn't have such a massive area needed to be covered with TPS.  So a two stage system could still be fully reusable, but wouldn't need so many new technologies and could use many more conventional technologies.
Just seems like trying to get all that into a SSTO reusable spaceplane required so many new technologies, that it would have pretty costly to develop, and probably would have had a lot more processing time between flights than they originally thought (like Shuttle).

A "Shuttle 2" could have used lighter materials, and more simple lifting body shape that required a smaller TPS, and could have used a metallic TPS. (get rid if those big wings if you can).  Although 2 stage, it still could be fully reusable and take off from a runway.  You could have acheived some of the goals of Venturestar, but it could have been cheaper, more conventional.  Just wouldn't be as sexy as full SSTO.
;-)

Offline spacecane

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Re: What would a better STS Have Looked Like?
« Reply #35 on: 04/26/2012 12:30 PM »
How important was being able to return payloads?  I would think it would make more sense to have internal fuel tanks (in a series staged design so that you need much less fuel in the orbiter) and external payload.  Then the expendable part of the design would just be a payload fairing.  Picture the payload attached to the belly (like the ET is only much smaller).  Then a payload fairing over it for ascent that can be jettisoned when high enough.

There would be a robot arm stowed that could reach around the bottom for deployment. 

If there was really a need to return payload you could bring up a reentry pod as a payload that would basically be an ablative heat shield and parachute with some thrusters for reentry.  The shuttle could grab the satellite, put it in the reentry pod and then the payload would enter and splash down somewhere.

The orbiter itself could have a small payload bay like a pickup truck bed.

Seems to me that it would be more cost effective to expend simple cheap payload fairings than complicated and expensive fuel tanks.

Online Lobo

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Re: What would a better STS Have Looked Like?
« Reply #36 on: 04/26/2012 04:01 PM »
How important was being able to return payloads?  I would think it would make more sense to have internal fuel tanks (in a series staged design so that you need much less fuel in the orbiter) and external payload.  Then the expendable part of the design would just be a payload fairing.  Picture the payload attached to the belly (like the ET is only much smaller).  Then a payload fairing over it for ascent that can be jettisoned when high enough.

There would be a robot arm stowed that could reach around the bottom for deployment. 

If there was really a need to return payload you could bring up a reentry pod as a payload that would basically be an ablative heat shield and parachute with some thrusters for reentry.  The shuttle could grab the satellite, put it in the reentry pod and then the payload would enter and splash down somewhere.

The orbiter itself could have a small payload bay like a pickup truck bed.

Seems to me that it would be more cost effective to expend simple cheap payload fairings than complicated and expensive fuel tanks.

Interesting concept. 

I really think the large downmass and down volume capability of the Shuttles were never realized during STS.  NOt sure why.  either over estimated at the program's conception, or flight rates just never materialized enough to have programs that could really utilize it.  Some downmass is good, I know they are looking forward to Dragon's downmass capability.  So a shuttle with a small payload bay for [relatively] small downmass capability would probably be very useful.  Not sure how important the full shuttle payload bay turned out to be for bringing down satillites and such though.

Offline saturnapollo

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Re: What would a better STS Have Looked Like?
« Reply #37 on: 04/26/2012 04:31 PM »
Although somewhat fictional, this was what I had in mind for a next generation shuttle. Definitely have to get away from the side mounted orbiter so I thought one mounted at the apex would allow for some sort of escape.

And again probably do not need a huge payload bay.

Keith

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Offline Downix

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Re: What would a better STS Have Looked Like?
« Reply #38 on: 04/26/2012 04:49 PM »
How important was being able to return payloads?  I would think it would make more sense to have internal fuel tanks (in a series staged design so that you need much less fuel in the orbiter) and external payload.  Then the expendable part of the design would just be a payload fairing.  Picture the payload attached to the belly (like the ET is only much smaller).  Then a payload fairing over it for ascent that can be jettisoned when high enough.

There would be a robot arm stowed that could reach around the bottom for deployment. 

If there was really a need to return payload you could bring up a reentry pod as a payload that would basically be an ablative heat shield and parachute with some thrusters for reentry.  The shuttle could grab the satellite, put it in the reentry pod and then the payload would enter and splash down somewhere.

The orbiter itself could have a small payload bay like a pickup truck bed.

Seems to me that it would be more cost effective to expend simple cheap payload fairings than complicated and expensive fuel tanks.
Shuttle II used a payload pod, but on its back:

https://sites.google.com/site/spaceodysseytwo/spacelvs/lrcsts2b.gif
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Offline jtrame

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Re: What would a better STS Have Looked Like?
« Reply #39 on: 04/26/2012 05:59 PM »
Although somewhat fictional, this was what I had in mind for a next generation shuttle. Definitely have to get away from the side mounted orbiter so I thought one mounted at the apex would allow for some sort of escape.

And again probably do not need a huge payload bay.

Keith

http://www.keithmcneill.pwp.blueyonder.co.uk/Omega1g%20-%20small.jpg
http://www.keithmcneill.pwp.blueyonder.co.uk/Omega3l%20SMALL.jpg
http://www.keithmcneill.pwp.blueyonder.co.uk/Omega12h%20SMALL.jpg

Nice. 

Offline 93143

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Re: What would a better STS Have Looked Like?
« Reply #40 on: 04/26/2012 06:21 PM »
VentureStar would have... had a much larger surface area exposed to damage in LEO, and a much larger surface exposed to the extremes of reentry.  Seems those things would in reality necessitate a LOT more on ground process than originally thought (just as the Shuttle did), and wouldn't surprise me if significantly more than the Shuttle.

No, the larger surface area is one reason it wouldn't have required as much.  The lower ballistic coefficient meant it could use an advanced metallic TPS, which was much more robust and much easier to refurbish.
« Last Edit: 04/26/2012 06:24 PM by 93143 »

Offline Gene DiGennaro

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Re: What would a better STS Have Looked Like?
« Reply #41 on: 04/26/2012 07:33 PM »
At the time of the early 70s shuttle downmass was considered extremely important. Again read Heppenheimer's book. ( it's free online http://history.nasa.gov/SP-4221/contents.htm ) It was thought that having the shuttle's ability to bring malfunctioning satellites back to earth would lead to cheaper satellites.

Here's how it was thought to work. Satellites were and still are built to expensive high reliability standards. There exists a whole process for approval of materials and equipment for use in space. It HAS to work, no-one can go and fix it if it fails.

Shuttle was going to change all that. The downmass capability meant that less expensive, less reliable, more commercial off-the-shelf material could be used in satellite construction. If it failed prematurely, there would be less concern. After we could send a shuttle crew up to repair in situ or bring home malfunctioning satellites. This was a major selling point of shuttle.

I also remember a Newsweek article from about 1976 or so showing how the DoD could use the shuttle to kidnap Soviet satellites from orbit. What a way to trigger WWIII!

Offline spacecane

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Re: What would a better STS Have Looked Like?
« Reply #42 on: 04/27/2012 11:29 AM »
At the time of the early 70s shuttle downmass was considered extremely important. Again read Heppenheimer's book. ( it's free online http://history.nasa.gov/SP-4221/contents.htm ) It was thought that having the shuttle's ability to bring malfunctioning satellites back to earth would lead to cheaper satellites.

Here's how it was thought to work. Satellites were and still are built to expensive high reliability standards. There exists a whole process for approval of materials and equipment for use in space. It HAS to work, no-one can go and fix it if it fails.

Shuttle was going to change all that. The downmass capability meant that less expensive, less reliable, more commercial off-the-shelf material could be used in satellite construction. If it failed prematurely, there would be less concern. After we could send a shuttle crew up to repair in situ or bring home malfunctioning satellites. This was a major selling point of shuttle.

I also remember a Newsweek article from about 1976 or so showing how the DoD could use the shuttle to kidnap Soviet satellites from orbit. What a way to trigger WWIII!

Interesting info.  It was a great idea except for the fact that the highest the shuttle ever reached was almost 22,000 miles too low to reach a satellite in GSO to bring down for repair.  I guess the satellite could have been sent down to a lower orbit for capture? 

If we were to design this better STS now, how much downmass would be required on a regular basis.  In my concept with a payload pod to save on vehicle size there would always be the option to bring up a reentry craft if a large satellite needed to be brought to earth.  The reentry craft would just be a cover with an ablative heat shield, some thrusters to control the de-orbit and a parachute system to splash down somewhere. 

My concept of attaching payload to the exterior of the orbiter would eliminate the need to have the ridiculously large payload bay of the Shuttle.  In order for my concept to work it would have to be a series staged design so as not to have to carry so much fuel for the second stage. 

For the orbiter, I'm picturing a Dreamlifter merged with a Centaur.  The crew cabin and small payload bay would be down the center.  The fuel tanks to the left and right.  The engine(s) in the back.  The docking adapter would probably need to move to the top.  The first stage booster would be some kind of RP1/LOX flyback booster.  The first stage booster should be common with expendable 2nd stages for cargo only launches.  No reason for people to go on every launch like STS was planned for.
« Last Edit: 04/27/2012 05:28 PM by spacecane »

Offline spaceStalker

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Re: What would a better STS Have Looked Like?
« Reply #43 on: 04/27/2012 01:35 PM »
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Online Lobo

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Re: What would a better STS Have Looked Like?
« Reply #44 on: 04/27/2012 03:43 PM »
VentureStar would have... had a much larger surface area exposed to damage in LEO, and a much larger surface exposed to the extremes of reentry.  Seems those things would in reality necessitate a LOT more on ground process than originally thought (just as the Shuttle did), and wouldn't surprise me if significantly more than the Shuttle.

No, the larger surface area is one reason it wouldn't have required as much.  The lower ballistic coefficient meant it could use an advanced metallic TPS, which was much more robust and much easier to refurbish.

Ahh...interesting.  I wouldn't have guessed that.
Good to know.
Was the Shuttle too large for something like PICA, but too small for some type of metallic TPS, or something?

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