Proposed versions of spacecraft that were (or weren't) made.

[YumonStudios]

On 4/8/2016 at 0:51 PM, sevenperforce said:

Then by all means let's replace it with an SSTO-capable airbreathing VentureStar.

I don't know if airbreathing would help Venturestar much. It was already way too complex and advanced, anyways.

21 hours ago, todofwar said:

Allot of hate for the shuttle here, but it's probably my favorite design that actually flew, and was the workhorse of the space program long after it was supposed to be retired. It remains the only succesful reusable system, and while it demonstrated many flaws with reusability a part of me still thinks we abandoned the basic concept too early. Who knows, maybe a few more iterations on the shuttle would have made it cheaper to refit in between missions. 

The Shuttle was hated because it was basically a horrible design of a spacecraft, and had insanely high costs per kg.

And making more iterations of the SHuttle pretty much ended when the economics of the original Shuttle became apparent, and the launch rate crashed after Challenger. It could have been revived during the better-faster-cheaper era, but ultimately, SSTOs were preferred.

20 hours ago, Northstar1989 said:

Let's not forget THIS baby:

https://en.wikipedia.org/wiki/Sea_Dragon_%28rocket%29

 

Would have been a great low-cost option for a Mars mission- but too high of a payload capacity for anything much smaller...

 

Regards,

Northstar

UNfortunately, it is a Big Dumb Booster. Launch a Mars Mission on it, and you might just lose it all in a launch explosion.

9 hours ago, Nibb31 said:

Not really. It was just a winged capsule that weighed much more than a conventional capsule. As a result, it launched on top of an expendable rocket that was much larger than it needed to be. It also had no actual operational capability (like docking, crew transfer, EVA, etc...).

I remember one of the primary problems was a lack of use for that thing. Sounds familiar...

9 hours ago, Nothalogh said:

You know that the design proposal included crew transfer and docking as part of further development, right? 

The initial X-20, was a mercury analogue, further development would have matched and likely exceeded  Gemini and Apollo. 

If Dyna Soar had been done, we'd have never had to mess with the absolute silliness of the Shuttle trying to be both crew transfer and a cargo lifter at once.

And before you say it was an unworkable design, the USAF is running the X-37B, which is basically the Dyna Soar reborn. 

We have no clue why the USAF has the X-37B running. We do know, however, the USAF probably has no need for a manned program.

Also, X-20 was cancelled and replaced by MOL-Gemini, coming to the conclusion the effort of making Dyna-Soar was too great. It might have survived if it was a NASA program, but the USAF didn't ever need lifting bodies back then. It also soon realized it had no need for a manned program, so if one didn't happen, the other one would eventually.

It was just a matter of time, the X-20 program was doomed from the start.

https://en.wikipedia.org/wiki/Boeing_X-20_Dyna-Soar#Problems

[SSgt Baloo]

Lots of neat stuff for me to look at and wonder. Thanks, guys!

[Nibb31]

14 hours ago, Nothalogh said:

You know that the design proposal included crew transfer and docking as part of further development, right? 

The initial X-20, was a mercury analogue, further development would have matched and likely exceeded  Gemini and Apollo. 

If Dyna Soar had been done, we'd have never had to mess with the absolute silliness of the Shuttle trying to be both crew transfer and a cargo lifter at once.

And before you say it was an unworkable design, the USAF is running the X-37B, which is basically the Dyna Soar reborn. 

Except the X-37B is unmanned, and the USAF actually has a use for it.

It was unworkable in the early 1960's. They didn't have the TPS material (it would have likely had an expendable ablative TPS like the X-15). It probably wouldn't have been controllable on reentry. They didn't even have fly-by-wire in those days.

In the end, there was no real use for DynaSoar that couldn't be fulfilled with a much simpler design.

But I agree that if DynaSoar had been done, they would probably have given up on spaceplanes much earlier and we would have been flying proper capsules through the 80's and 90's.

[SSgt Baloo]

On 4/9/2016 at 8:27 PM, Northstar1989 said:

Let's not forget THIS baby:

https://en.wikipedia.org/wiki/Sea_Dragon_%28rocket%29

 

Would have been a great low-cost option for a Mars mission- but too high of a payload capacity for anything much smaller...

 

Regards,

Northstar

THIS is a Kerbal concept. Has anyone figured out how to model this in KSP? Launching a floating rocket from the ocean, just off shore sounds like fun, even if it may not be practical in the real world.

[kerbiloid]

2 hours ago, SSgt Baloo said:

THIS is a Kerbal concept. Has anyone figured out how to model this in KSP? Launching a floating rocket from the ocean, just off shore sounds like fun, even if it may not be practical in the real world.

At least two mods.

The relevant one — Necrobones' Sea Dragon

[Laie]

[Sea Dragon]

20 hours ago, YumonStudios said:

UNfortunately, it is a Big Dumb Booster. Launch a Mars Mission on it, and you might just lose it all in a launch explosion.

Well, it wasn't supposed to launch the spacecraft or crew, but supplies. 90% success rate at 50% launch cost is a reasonable proposition if (and only if) the payload is cheap and easy to replace.

 

[SSgt Baloo]

10 hours ago, kerbiloid said:

At least two mods.

The relevant one — Necrobones' Sea Dragon

I'll look for it in my CKAN menu.

Edited April 11, 2016 by SSgt Baloo

[todofwar]

VASIMIR looks really intriguing as an engine concept. Apparently there was some thought put in to mounting one on the ISS to keep it in stable orbit for a longer period of time. 

[Kryten]

7 minutes ago, todofwar said:

VASIMIR looks really intriguing as an engine concept. Apparently there was some thought put in to mounting one on the ISS to keep it in stable orbit for a longer period of time. 

That would've just been a test unit, the power requirement precluded using it operationally. In the end the power requirement was also so high they couldn't justify it on a single experiment.

On 4/9/2016 at 4:27 AM, Northstar1989 said:

Would have been a great low-cost option for a Mars mission- but too high of a payload capacity for anything much smaller...

The cost figures for Sea Dragon assumed that development and infrastructure costs were amortised over at least 240 flights with a minimum of 12 a year; for just a few flights, the cost would've been monstrous. Imagine the facilities they'd have to build just to e.g. test that first stage engine, or put the thing together.

Edited April 11, 2016 by Kryten

[Bill Phil]

On April 10, 2016 at 0:59 AM, Nibb31 said:

Except the X-37B is unmanned, and the USAF actually has a use for it.

It was unworkable in the early 1960's. They didn't have the TPS material (it would have likely had an expendable ablative TPS like the X-15). It probably wouldn't have been controllable on reentry. They didn't even have fly-by-wire in those days.

In the end, there was no real use for DynaSoar that couldn't be fulfilled with a much simpler design.

But I agree that if DynaSoar had been done, they would probably have given up on spaceplanes much earlier and we would have been flying proper capsules through the 80's and 90's.

If they had done DynaSoar and Space Launching System that rocket wouldn't be getting a replacement anytime soon. We still haven't been able to match some of the specs.

[sevenperforce]

On 4/10/2016 at 11:06 PM, YumonStudios said:

I don't know if airbreathing would help Venturestar much. It was already way too complex and advanced, anyways.

Because it needed to be SSTO. Giving it drop-away-and-RTLS boosters for takeoff thrust and crossfeed would give it much better margins, enough to make up for the greater dry mass of an airbreathing system.

[Northstar1989]

On 4/10/2016 at 10:06 PM, YumonStudios said:

UNfortunately, it is a Big Dumb Booster. Launch a Mars Mission on it, and you might just lose it all in a launch explosion.

That's not how Big Dumb Boosters work...

Big Dumb Boosters are so-named because of their poor mass-ratios (ratio of mass on the launchpad to payload), *not* because they are unreliable.

In fact, the Sea Dragon would have been MORE reliable than the Saturn V- mainly because with a Big Dumb Booster you assume a certain amount of leeway for everything in manufacturing (this is why they are cheap- they have very loose manufacturing margins, which brings down manufacturing costs immensely), whereas with a "Smart Booster" you design everything to work just-so, with *very* tight manufacturing margins, and if ANYTHING goes wrong, the whole rocket tends to fail...

The greatest difficulty with something like the Sea Dragon was its ludicrous size.  It would have been big, extremely cheap (for its payload capacity), more reliable than any other launch vehicle in existence at the time, and once again BIG.  That's why they called it the "Sea Dragon"- because it was so huge the only option would have been to launch it at sea, as no existing launchpad could have launched a rocket of that size...

 

On 4/10/2016 at 6:36 PM, Laie said:

[Sea Dragon]

Well, it wasn't supposed to launch the spacecraft or crew, but supplies. 90% success rate at 50% launch cost is a reasonable proposition if (and only if) the payload is cheap and easy to replace.

 

No, Sea Dragon was built for crew and would have been HIGHLY reliable (and definitely safer than the Saturn V).  Once again, Big Dumb Boosters like Sea Dragon aren't "Dumb" because of low reliability, they are "Big" and "Dumb" because of their terrible mass-ratios.  They are actually SAFER and *less* likely to fail than conventional "Smart" boosters...

I think the problem here is low-reliability concepts like Aquarius stealing the title "Big, Dumb, Booster".  Aquarius was neither Big (only 1 ton payload capacity) nor Dumb (its mass-ratio was comparable to "Smart" boosters), rather it relied on an only 66% target success rate for its launches to bring costs down by allowing looser engineering margins (whereas something like the Sea Dragon compensated with over-engineering to keep success rates extremely high, Aquarius simply swallowed high failure-rates as acceptable for cargo-launches...)

Aquarius only relied on water-launches because of its low reliability (to alleviate range-safety issues).  Unlike the Sea Dragon, which would have been *extremely* safe, but so huge that it could be supported by no existing launchpad...

 

Regards,

Northstar

Edited April 12, 2016 by Northstar1989

[Northstar1989]

On 4/10/2016 at 10:37 AM, SSgt Baloo said:

THIS is a Kerbal concept. Has anyone figured out how to model this in KSP? Launching a floating rocket from the ocean, just off shore sounds like fun, even if it may not be practical in the real world.

Sea-launches are *very* practical in the real world.  They eliminate a lot of range-safety issues and the need for a launchpad entirely, thus bringing down costs considerably...

And, I think history has shown that the prohibitive limit on space exploration has been its cost.  Politicians (shortsightedly) simply aren't willing to spend very heavily on space programs, as they are too ignorant to see their many benefits.  If we can bring down the cost of getting mass to orbit (which the Sea Dragon would have done, for very large payloads- or something like the Aquarius that can't properly be called a "Big, Dumb Booster" due to its low reliability could have done for small payloads) we can get a lot more done in space exploration.

Speaking of Big Dumb Boosters, I think the *REAL* problem was nobody designed one for small to medium-sized payloads (except the Aquarius- which once again didn't really qualify as a Big Dumb Booster as it had good mass-ratios and wasn't very reliable).  A Big Dumb Booster designed for small payloads might have been as large as a medium-sized "Smart" Booster (due to poor mass-ratios), but it would have been just as reliable (in fact more so), and a lot cheaper per kg of payload to orbit...

The Aquarius never really hit it off due to its poor reliability (politicians don't want to see failed rocket launches in the news), but once again it wasn't really a true Big Dumb Booster.  It didn't meet the primary criteria of having a poor mass-ratio, and besides there is nothing about a Big Dumb Booster that says that having a low reliability is OK (and Sea Dragon was VERY reliable).

 

Regards,

Northstar

Edited April 12, 2016 by Northstar1989

[tg626]

RHOMBUS

http://www.astronautix.com/lvs/rombus.htm

[Nibb31]

On 4/12/2016 at 7:26 AM, Northstar1989 said:

Sea-launches are *very* practical in the real world.  They eliminate a lot of range-safety issues and the need for a launchpad entirely, thus bringing down costs considerably...

Range safety isn't nearly a major cost in the launch industry, so eliminating it wouldn't bring down costs considerably.

Actually, sea launches also have range safety requirements, with NOTAMs and areas that need to be free of maritime traffic.

Quote

And, I think history has shown that the prohibitive limit on space exploration has been its cost.  Politicians (shortsightedly) simply aren't willing to spend very heavily on space programs, as they are too ignorant to see their many benefits.  If we can bring down the cost of getting mass to orbit (which the Sea Dragon would have done, for very large payloads- or something like the Aquarius that can't properly be called a "Big, Dumb Booster" due to its low reliability could have done for small payloads) we can get a lot more done in space exploration.

Sea Dragon was a paper rocket. Paper rockets are always better than real ones.

There are a lot of "good ideas" that were rejected for very good reasons. Since there was no real engineering put into Sea Dragon, nobody knows if it would have been cost efficient or not.

The idea of building it in a shipyard, for example, was supposed to make it cheaper. Well, surprise, shipbuilding isn't cheap. It also isn't fast, so there would be a huge lead time between launches.

The idea was also based on the illusion that expendable rockets are somehow overengineered, which is a fallacy. They are not overly expensive for what they do. They are designed for a task, which is to be expendable, and if you want any type of reliability in your big dumb booster, you're going to need to follow pretty much the same comprimises in cost/performance/reliability. Modern expendable launchers are just about as dumb and cheap as you can get without compromising reliability.

Quote

(and Sea Dragon was VERY reliable).

Based on what data ? Sea Dragon didn't exist. 

 

Edited April 13, 2016 by Nibb31

[Laie]

18 hours ago, Northstar1989 said:

(and Sea Dragon was VERY reliable)

As testified by it's impeccable launch record: not a single failure!

(scnr)

Granted, it certainly had a lot of potential in the reliability department, being pressure-fed throughout. But that's also the main reason why I can't really imagine that it would have worked out. I trust that they got the numbers right and that a huge pressure vessel + inefficient engine can still go to space... but if that was as straightforward as it seems, it should by now have become the go-to approach even for landlocked boosters.

*looks around*

I don't see anything of that sort.

[Bill Phil]

1 hour ago, Laie said:

As testified by it's impeccable launch record: not a single failure!

(scnr)

Granted, it certainly had a lot of potential in the reliability department, being pressure-fed throughout. But that's also the main reason why I can't really imagine that it would have worked out. I trust that they got the numbers right and that a huge pressure vessel + inefficient engine can still go to space... but if that was as straightforward as it seems, it should by now have become the go-to approach even for landlocked boosters.

*looks around*

I don't see anything of that sort.

Sea Dragon was intended to be huge. So huge that a loss of ISO wouldn't hit it hard. But even in modern rockets, a drop of 5 seconds of ISP can reduce payload by so much that you can't allow it to drop that much. Starting with a lower ISP and the huge margins given by the design it's not that bad of an idea. But it has to be a huge design for that to work, with an already huge payload. Those aren't very common.

[Northstar1989]

On 4/12/2016 at 1:29 AM, Nibb31 said:

Range safety isn't nearly a major cost in the launch industry, so eliminating it wouldn't bring down costs considerably.

Actually, sea launches also have range safety requirements, with NOTAMs and areas that need to be free of maritime traffic.

Sea Dragon was a paper rocket. Paper rockets are always better than real ones.

There are a lot of "good ideas" that were rejected for very good reasons. Since there was no real engineering put into Sea Dragon, nobody knows if it would have been cost efficient or not.

The idea of building it in a shipyard, for example, was supposed to make it cheaper. Well, surprise, shipbuilding isn't cheap. It also isn't fast, so there would be a huge lead time between launches.

The idea was also based on the illusion that expendable rockets are somehow overengineered, which is a fallacy. They are not overly expensive for what they do. They are designed for a task, which is to be expendable, and if you want any type of reliability in your big dumb booster, you're going to need to follow pretty much the same comprimises in cost/performance/reliability. Modern expendable launchers are just about as dumb and cheap as you can get without compromising reliability.

Based on what data ? Sea Dragon didn't exist. 

 

In order:

(1)  Range-safety is LESS of an issue with sea-launches.  And it does drive up costs (although not significantly).  The emphasis was on the lack of need for a launchpad, though.

(2)  Shipbuilding isn't cheap in absolute terms, but it is RELATIVELY much, much cheaper than current methods of building spacecraft.  A ship is much cheaper in terms of cost for a given tonnage than building a spacecraft using current manufacturing methods.  It's like the difference between a really expensive car and a really expensive airplane- sure, a Ferrari isn't cheap, but a private jet is a heck of a lot more expensive.  Your argument holds no water (pun intended).

(3)  "Over-engineered" is the wrong choice of terms, and you know that.  The idea isn't that expendable rockets are over-engineered, in the sense that people spend too much time designing them- the idea is that expendable rockets needlessly over-emphasize performance instead of cost.  You *CAN* design a rocket that gets much worse performance (in terms of mass-ratio), is just as reliable, and is much cheaper.  All you have to do is trade off performance for cost, which is what a Big Dumb Booster is all about.

 

On the knitty-gritty level, a Big Dumb Booster works by having wider engineering-margins in its manufacture than a "Smart" Booster, such as to allow less precise manufacturing techniques.  For instance, if you say that the wall of X fuel tank needs to be 11 mm +/- 2% instead of 10.75 mm +/- 0.1% you're going to get a cheaper rocket despite having an overall less efficient design, because cheaper manufacturing techniques can be used.

This is how a Big Dumb Booster works- EVERYTHING is specified to a standard where there is more room for error in terms of its manufacture without part stresses falling outside acceptable safety limits, but the trade-off is that you get a much, much worse mass-ratio despite getting a better cost-per-kg to LEO...  The bigger rocket can't launch from any existing launchpad, so you have to launch it at sea (which is actually cheaper than building a new launchpad, but requires a bit more engineering to make work).  However the benefit is a lower cost-to-orbit, despite having a massively less efficient (but still extremely safe) rocket.

 

Regards,

Northstar

Edited April 20, 2016 by Northstar1989

[Northstar1989]

On 4/12/2016 at 6:49 PM, Laie said:

Granted, it certainly had a lot of potential in the reliability department, being pressure-fed throughout. But that's also the main reason why I can't really imagine that it would have worked out. I trust that they got the numbers right and that a huge pressure vessel + inefficient engine can still go to space... but if that was as straightforward as it seems, it should by now have become the go-to approach even for landlocked boosters.

*looks around*

I don't see anything of that sort.

You don't see anything like Sea Dragon anymore because the calculus has changed, so-to-speak.  We have achieved enough improvement in "Smart Booster" performance, that it makes much less sense to trade performance for cost now.

Sea Dragon was close to the peak of what a pressure-fed rocket could achieve (with MASSIVE benefit from the Square-Cube Law due to its huge size and RIDICULOUS expansion-ratios for its exhaust, including use of expandable nozzles), and the potential of such a design has only improved a little- mostly due to improvements in metallurgy and the economics of producing certain high-strength steel alloys (Sea Dragon was built mainly from steel, not aluminum, since it's easier to machine with existing low-cost techniques).

On the other hand, Smart Booster technology still hasn't reached its theoretical peak (Full Flow Staged Combustion still hasn't seen hardly any use yet, for instance, aside from talk of the yet-to-be-built next-generation "Raptor" engine being developed by Space-X), and Space-X has worked out methods to MASSIVELY improve the efficiency of manufacturing "traditional" high-strength Aluminum-alloy "Smart Boosters", and has developed technology for first-stage re-usability on top of that...

Compared to what Space-X has now, with the Falcon 9 (and soon the Falcon Heavy), Sea Dragon style rockets just don't make much sense anymore.  Big Dumb Boosters would only be slightly cheaper in terms of cost-per-kg than expendable Falcon 9's, and reusable Falcon 9's beat something like the Sea Dragon by a long shot... (and that's INCLUDING the fact that Sea Dragon was actually designed for limited first-stage re-usability om the cost equations: but more in the sense of the Shuttle in that certain parts would have had to rebuilt after every launch due to the hard-splashdown of the first stage...)

 

Sea Dragon and a Mars mission would have a much better (and cheaper) successor to Apollo and the Saturn V than the Shuttle and International Space Station.  But it's all water under the bridge now- stuff like Falcon 9 and Falcon Heavy are the way forward.  I just like to point at Sea Dragon and Big Dumb Boosters and say "Hah!  That's the way we *SHOULD* have gone after Apollo!"

 

Regards,

Northstar

Edited April 20, 2016 by Northstar1989

[fredinno]

 

On 4/12/2016 at 10:26 PM, Northstar1989 said:

Sea-launches are *very* practical in the real world.  They eliminate a lot of range-safety issues and the need for a launchpad entirely, thus bringing down costs considerably...

Really? If it was that great, then why is Sea Launch in dead water?

Also, launching it in the sea (in water) causes corrosion issues that increase rocket cost.

On 4/10/2016 at 4:36 PM, Laie said:

[Sea Dragon]

Well, it wasn't supposed to launch the spacecraft or crew, but supplies. 90% success rate at 50% launch cost is a reasonable proposition if (and only if) the payload is cheap and easy to replace.

 

But would you ever need 550T of supplies? If you sent that to the ISS, they'd never use it all.

On 4/12/2016 at 10:11 PM, Northstar1989 said:

That's not how Big Dumb Boosters work...

Big Dumb Boosters are so-named because of their poor mass-ratios (ratio of mass on the launchpad to payload), *not* because they are unreliable.

In fact, the Sea Dragon would have been MORE reliable than the Saturn V- mainly because with a Big Dumb Booster you assume a certain amount of leeway for everything in manufacturing (this is why they are cheap- they have very loose manufacturing margins, which brings down manufacturing costs immensely), whereas with a "Smart Booster" you design everything to work just-so, with *very* tight manufacturing margins, and if ANYTHING goes wrong, the whole rocket tends to fail...

The greatest difficulty with something like the Sea Dragon was its ludicrous size.  It would have been big, extremely cheap (for its payload capacity), more reliable than any other launch vehicle in existence at the time, and once again BIG.  That's why they called it the "Sea Dragon"- because it was so huge the only option would have been to launch it at sea, as no existing launchpad could have launched a rocket of that size...

 

No, Sea Dragon was built for crew and would have been HIGHLY reliable (and definitely safer than the Saturn V).  Once again, Big Dumb Boosters like Sea Dragon aren't "Dumb" because of low reliability, they are "Big" and "Dumb" because of their terrible mass-ratios.  They are actually SAFER and *less* likely to fail than conventional "Smart" boosters...

I think the problem here is low-reliability concepts like Aquarius stealing the title "Big, Dumb, Booster".  Aquarius was neither Big (only 1 ton payload capacity) nor Dumb (its mass-ratio was comparable to "Smart" boosters), rather it relied on an only 66% target success rate for its launches to bring costs down by allowing looser engineering margins (whereas something like the Sea Dragon compensated with over-engineering to keep success rates extremely high, Aquarius simply swallowed high failure-rates as acceptable for cargo-launches...)

Aquarius only relied on water-launches because of its low reliability (to alleviate range-safety issues).  Unlike the Sea Dragon, which would have been *extremely* safe, but so huge that it could be supported by no existing launchpad...

 

Regards,

Northstar

That raises the question if there is a single thing that need 550 T to LEO. A Mars Mission? 

Sure, but how many of those will you have? Maximum probably 2 per year. Not worth it.

 

Just use an SLS/Saturn V.

[Laie]

quoting 60 lines in order to add four of your own? tsk, tsk, tsk.

45 minutes ago, fredinno said:

But would you ever need 550T of supplies? If you sent that to the ISS, they'd never use it all.

You need to think big. From an early- or even mid- 60s point of view, the ISS would hardly qualify as station. A proper space station is a torus housing hundreds, providing regular shuttle service to the lunar colony.

Ever seen 2001? When the flick came out, it was considered a realistic showcase of what space travel could (and possibly even would) look like some 30 years onward. It wasn't very far out on the incredibility scale.

[SSgt Baloo]

Looky what I found! Flight-testing the 1/5 scale model of the Dyna-Soar in a wind tunnel.

https://youtu.be/o2QJFiafYfY

http://www.popsci.com/space-plane-wasnt-everything-you-never-needed-know-about-dyna-soar

 

[DDE]

* sigh * Let's get to crazy pics, shall we?

Energiya-Vulkan. 180 t to parking orbit. SLS's big Rushn aunt.

Also, the grossly underused TKS, which never flew manned. Having a sizeable habitable compartment under the return vehicle is interesting; I wonder what a slightly beefier version could be with modular propulsion busses.