Author Topic: What would a second generation Space Shuttle look like?  (Read 50460 times)

Offline Dadam

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American Space Shuttles were designed as heavy duty transportation systems to Earth's orbit. As far as I understand they were supposed to:

* carry big loads
* carry large crew
* be able to bring down whatever they bring up
* be simple to maintain
* be cheap to fly
* fly very often

and they failed most of it. But with big failures comes big experience, and I guess that NASA would do many things differently if they designed shuttle again today. I wonder how would such a shuttle look like.

First thing that came to my mind is that big part of the maintenance was done on engines (right?). So it could actually be better to have cheap engines and either discard them after each flight or mount them to the ET (similar to Buran).

Please let's not discuss about if this would be reasonable (it would not, I know). Also please avoid (near) future technologies, as the Sabre engine or ITS.

Thank you
« Last Edit: 12/19/2018 02:20 pm by Lar »

Offline redliox

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Re: How would a second generation Space Shuttle look like?
« Reply #1 on: 02/04/2017 08:31 pm »
Short answer: depends on who you ask to build it. 

If you asked NASA, it'd become either vaporware like the X-33/Venturestar or another quagmire (at least in development) like the original space shuttle.

However your wish is pretty much happening thanks to Sierra Nevada's Dreamchaser.  Assuming you're talking about an aerodynamic vehicle, I'd look to that as a model for a would-be-2nd-Gen shuttle, or perhaps even the stillborn X-38 (which is mostly the same thing).  It would probably be something akin to Dreamchaser but scaled up some.

There were many problems with the old shuttle, mainly with safety.  A new shuttle would either have to piggyback on another winged vehicle or, like Dreamchaser, become an elaborate nosecone on a large rocket.  Can you imagine an SLS with a giant Dreamchaser crowning it?  It'd be an awesome combo...but too tall and maybe even too heavy to move safety.

The 2nd-Gen shuttle would probably be similar to the shuttle in having the cargo bay in back and the crew up from plus docking from a vertical-oriented airlock instead of a rear or forward facing one like most capsules.  Guesswork as to how big the cargo bay could be.  If you wanted to be efficient there could be a cargo-only vehicle and perhaps the crew version would have not so much a cargo bay but a maintenance bay (think of a small cargo bay just large enough to do Hubble-esque work with all the tools, robot arm, but not for actual transport).

So if I had to visualize a 21st century shuttle (that's at least bigger than Dreamchaser and with STS-similar capability) I'd picture the following:

1) Slightly shorter
2) Launches atop a large rocket in a nosecone position
3) Smaller cargo bay but with robotic arms and room for working on satellites
4) Large cargo strictly for separate vehicle (some supplies still transportable with crew but no ISS module hauling)
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Offline nacnud

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Re: How would a second generation Space Shuttle look like?
« Reply #2 on: 02/04/2017 08:56 pm »
Honestly, Spacexs ITS just about nails it. You would need to modify the spaceship to have better access to the cargo bay but that's about it.

Offline hkultala

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Re: How would a second generation Space Shuttle look like?
« Reply #3 on: 02/04/2017 09:33 pm »
Yep, spaceX ITS is very close, just may need modification to cargo access.

Orbital refueling could also be dropped as it's not needed when destinations are close to earth.

Even without refueling, ITS could probably reach at least GTO with reasonable payload, which STS could not at all, even with zero payload.


Thought BFS/ITS might be oversized so smaller version of the same concept might be cheaper if the goal is just do what shuttle was originally going to do.
« Last Edit: 02/04/2017 09:34 pm by hkultala »

Offline john smith 19

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Re: How would a second generation Space Shuttle look like?
« Reply #4 on: 02/04/2017 09:43 pm »
Just a reminder that the biggest problems with the Shuttle were it's funding arrangements.

Assuming you can get a sensible funding arrangement you then need to work out what it's going to do.

A "shuttle" implies regular, routine access to space.

So what is it sized to carry? A satellite? A satellite with upper stage to get to GEO? Space probes to other planets? ISS sized modules? Experiment racks?

BTW It can be said there already is a 2nd generation shuttle operating.  It's called the X37b. It's uncrewed yet manages an unpowered runway landing.

There is a perception that the Shuttle "proves" you should not have crew with other payloads but SX wants to go with as much commonality as possible between the crew and cargo Dragon versions (although the new version looks more like a lifting body). My sense is most of the Shuttle living space could be made into a removable module, increasing cargo capacity. 

Shuttle had an actual failure rate of about 1.5%. For prolonged, large scale use this failure rate has to drop by orders of magnitude. That suggests designing out failure modes and avoiding the unnecessary design constraints (like needing return to the launch site on 1 orbit, or engines you can't turn off). 

The reason why the Shuttle had no escape system was the (misguided) belief it's failure rate (in the 10s of 1000s) would not need it.  Had that belief been correct it would not have. It wasn't. The question is could a next gen Shuttle be designed to actually deliver that safety level, or should an LES be designed in from day one?

Then there are the turnaround issues.
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP stainless steel structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Offline hkultala

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Re: How would a second generation Space Shuttle look like?
« Reply #5 on: 02/04/2017 09:50 pm »
Just a reminder that the biggest problems with the Shuttle were it's funding arrangements.

Assuming you can get a sensible funding arrangement you then need to work out what it's going to do.

A "shuttle" implies regular, routine access to space.

So what is it sized to carry? A satellite? A satellite with upper stage to get to GEO? Space probes to other planets? ISS sized modules? Experiment racks?

7 tonnes to GTO, 25 tonnes to LEO is quite a good size. Can both launch the biggest comsats, and can launch quite big space station modules and bring lots off supplies and crew to space station.


Quote
BTW It can be said there already is a 2nd generation shuttle operating.  It's called the X37b. It's uncrewed yet manages an unpowered runway landing.

STS was a space launch system. X-37b is not. X-37b is just a payload, like a satellite that can also land.

So x-37b is totally different thing.


Quote
There is a perception that the Shuttle "proves" you should not have crew with other payloads but SX wants to go with as much commonality as possible between the crew and cargo Dragon versions (although the new version looks more like a lifting body). My sense is most of the Shuttle living space could be made into a removable module, increasing cargo capacity. 

Shuttle mostly proved that feature creep sucks, nothing else.

Quote
Shuttle had an actual failure rate of about 1.5%. For prolonged, large scale use this failure rate has to drop by orders of magnitude. That suggests designing out failure modes and avoiding the unnecessary design constraints (like needing return to the launch site on 1 orbit, or engines you can't turn off). 

Yep.

Quote
The reason why the Shuttle had no escape system was the (misguided) belief it's failure rate (in the 10s of 1000s) would not need it.  Had that belief been correct it would not have. It wasn't. The question is could a next gen Shuttle be designed to actually deliver that safety level, or should an LES be designed in from day one?

Another reason was that there was no way to implement a LES system into shuttle without huge performance penalty. It does not cost much performance when the capsule is small and only contains the humans. But when capsule, cargo space and 2nd stage engines are all together, the performance cost is much bigger.
« Last Edit: 02/04/2017 09:53 pm by hkultala »

Online Coastal Ron

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Re: How would a second generation Space Shuttle look like?
« Reply #6 on: 02/04/2017 10:40 pm »
Just a reminder that the biggest problems with the Shuttle were it's funding arrangements.

Assuming you can get a sensible funding arrangement you then need to work out what it's going to do.

A "shuttle" implies regular, routine access to space.

So what is it sized to carry? A satellite? A satellite with upper stage to get to GEO? Space probes to other planets? ISS sized modules? Experiment racks?

7 tonnes to GTO, 25 tonnes to LEO is quite a good size. Can both launch the biggest comsats, and can launch quite big space station modules and bring lots off supplies and crew to space station.

Why do we need one vehicle that can do everything?  Sure the government Space Transportation System (STS) could have done just about anything we need done today, but that flexibility came at a great cost - both in operational costs and human lives.

Define the problem that needs to be solved, THEN design the solution.  Designing the solution first is just indulging fantasy...
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline Darkseraph

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Re: How would a second generation Space Shuttle look like?
« Reply #7 on: 02/04/2017 11:21 pm »
Honestly, Spacexs ITS just about nails it. You would need to modify the spaceship to have better access to the cargo bay but that's about it.

In a minority here, but something similar in principle to this (two stage, fully reusuable, methalox engines) but not quite this large. Something much closer to New Glenn in scale seems to be a more prudent path for a '2nd Generation Space Shuttle'. The enormous size of the ITS makes me fear it will be plagued by the problem with the first generation Space Shuttle: low flight rates, high fixed costs.
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Offline Arch Admiral

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Re: How would a second generation Space Shuttle look like?
« Reply #8 on: 02/05/2017 01:55 am »
X-37 has fixed a few of the problems that crippled the Shuttle Orbiter as a reentry vehicle:

- Separate wing and tail surfaces allow much greater variation in CoG during a mission. Delta-wing and lifting-body designs require careful control of CoG. This was a persistent problem with Shuttle and almost every mission flew with lead ballast blocks, over 2 tons in the nose for the first half of the program.

- Eliminated the hydraulic system and the hydrazine APUs which were a constant source of trouble both on X-15 and Shuttle. Control surfaces have electric actuators like modern aircraft.

- Eliminated the human pilots and their big windows, too dangerous in the current space junk environment.

- Switched from naked side-mount position to safe location in standard payload shroud. Unfortunately this makes launch escape very difficult - this is why Dream Chaser has been downgraded to cargo only.

All these improvements should be in Shuttle Mk.2. But some intractable problems still remain:

- toxic and explosive hypergolic propellants, still not replaced with mythical "green" substitutes. Note the elaborate safing procedures after each X-37 landing by a crew in protective suits.

- fragile ceramic thermal protection, difficult to protect from space junk.

- excessive weight. A winged or lifting-body RV is still about 3x the weight of an equivalent ballistic vehicle, and always will be. Having a spacecraft land at an airport makes as much sense as an aircraft landing at a railroad station.

So I don't think a Shuttle 2.0 will exist in the foreseeable future.


Offline redliox

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Re: How would a second generation Space Shuttle look like?
« Reply #9 on: 02/05/2017 03:10 am »
So I don't think a Shuttle 2.0 will exist in the foreseeable future.

*coughDREAMCHASERcough*
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Offline TakeOff

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Re: How would a second generation Space Shuttle look like?
« Reply #10 on: 02/05/2017 04:03 am »
The Russians got it right with their Energia/Buran system. It could fly uncrewed to remotely controlled service or collect a satellite from orbit. Its launch stack could, and did, fly without shuttle, so the SLS was already a part of it. And its liquid boosters still fly as independent Zenith launchers.

Offline russianhalo117

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Re: How would a second generation Space Shuttle look like?
« Reply #11 on: 02/05/2017 04:36 am »
The Russians got it right with their Energia/Buran system. It could fly uncrewed to remotely controlled service or collect a satellite from orbit. Its launch stack could, and did, fly without shuttle, so the SLS was already a part of it. And its liquid boosters still fly as independent Zenith launchers.
It was also possible with STS to fly unmanned with the installation of a large cable connecting forward and aft deck controls and a smaller cable as needed connecting mid-deck with flight deck. I forget the exact name of the cables.

Offline TakeOff

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Re: How would a second generation Space Shuttle look like?
« Reply #12 on: 02/05/2017 06:11 am »
The Russians got it right with their Energia/Buran system. It could fly uncrewed to remotely controlled service or collect a satellite from orbit. Its launch stack could, and did, fly without shuttle, so the SLS was already a part of it. And its liquid boosters still fly as independent Zenith launchers.
It was also possible with STS to fly unmanned with the installation of a large cable connecting forward and aft deck controls and a smaller cable as needed connecting mid-deck with flight deck. I forget the exact name of the cables.
I think that was implemented as an afterthought when another seven astronauts were killed on a cargo mission where they were not needed, had the shuttle been rationally designed. It wasn't considered to be a permanent solution, just a quick fix for the last few launches. They even kept a second shuttle prepared for a rescue mission, as if killing two crews would be better than killing one.

Online zodiacchris

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Re: How would a second generation Space Shuttle look like?
« Reply #13 on: 02/05/2017 06:31 am »
That is a bit harsh!  :o Besides, the probability of the second shuttle floundering in orbit, too, would have been low...

Offline TakeOff

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Re: How would a second generation Space Shuttle look like?
« Reply #14 on: 02/05/2017 07:20 am »
That is a bit harsh!  :o Besides, the probability of the second shuttle floundering in orbit, too, would have been low...
When a crewed launcher fails it is usually grounded until the causes have been investigated and solved. To instead immediately launch another (crewed) copy of the failed space craft one could double the loss. Doubleplus ungood, to speak with CNN today.

Offline Proponent

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Re: How would a second generation Space Shuttle look like?
« Reply #15 on: 02/05/2017 09:43 am »
Re the OP, here are two old threads on similar topics:

Shuttle as X-Vehicle, and
What would a better STS have looked like?.

Offline Proponent

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Re: How would a second generation Space Shuttle look like?
« Reply #16 on: 02/05/2017 09:58 am »
7 tonnes to GTO, 25 tonnes to LEO is quite a good size. Can both launch the biggest comsats, and can launch quite big space station modules and bring lots off supplies and crew to space station.

A Shuttle-like vehicle would be much more massive than its payload.  That means that it's payload capability decreases very rapidly as orbital altitude (or inclination) increases.  A Shuttle-like vehicle with 25 tonnes' capability to LEO would likely have no capability at all to GTO.  A reusable tug would be the way to go.

Offline Proponent

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Re: How would a second generation Space Shuttle look like?
« Reply #17 on: 02/05/2017 10:06 am »
I think there's a message in the fact that of the four crewed space vehicles placed in development since the Shuttle (ESA's Hermes, Orion, Dragon and CST-100 [make it 5 if you count Dream Chaser]), none looks much like a Shuttle.  And Blue Origin isn't going the route of a Shuttle either.  True, Hermes and Dream Chaser have wings, but only for a small crew/cargo capsule, not for a major propulsion unit.

Offline Bob Shaw

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Re: How would a second generation Space Shuttle look like?
« Reply #18 on: 02/05/2017 10:56 am »
I think there's a message in the fact that of the four crewed space vehicles placed in development since the Shuttle (ESA's Hermes, Orion, Dragon and CST-100 [make it 5 if you count Dream Chaser]), none looks much like a Shuttle.  And Blue Origin isn't going the route of a Shuttle either.  True, Hermes and Dream Chaser have wings, but only for a small crew/cargo capsule, not for a major propulsion unit.

Buran, and a couple of other Soviet designs?

Offline Oli

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Re: How would a second generation Space Shuttle look like?
« Reply #19 on: 02/05/2017 12:48 pm »
The first shuttle should have looked like this (from here).  :)
« Last Edit: 02/05/2017 12:51 pm by Oli »

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