Author Topic: What would a second generation Space Shuttle look like?  (Read 50450 times)

Offline Proponent

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Re: How would a second generation Space Shuttle look like?
« Reply #20 on: 02/05/2017 02:23 pm »
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?

Good point -- Buran was a major omission in my claim (though were I in an argumentative mood, I might try to convince that, since Buran's orbiter lacked a main propulsion system, it functionally resembled Hermes or Dream Chaser more than the Shuttle).

There is, however, a two-pronged argument that Buran supports my main thesis that Shuttle-like vehicles don't make much sense.  Firstly, it flew but once.  Even after having sunk the cost of developing it, the Russians decided Buran wasn't worth keeping.  Soviet space scientist and administrator Roald Sageev said, "It went up.  It came down.  But it had absolutely no scientific value" [James Moltz, 2011.  The Politics of Space Security: Strategic Restraint and the Pursuit of National Interests, 2nd ed. (Stanford Univ. Press), p. 218 -- see attached image].  Granted there were non-scientific factors to be considered as well, but that the top space-science official saw no benefit to Buran is a negative indicator as to its utility.

Secondly, there is a credible and devastating (to the Shuttle) argument as to why the Soviets developed Buran in the first place.  According to Stephen Garber's master's thesis at Virginia Tech, the Soviets analyzed the Shuttle and realized that it made no economic sense (if only the US government had been so wise!).  In the flattering but sadly mistaken belief that the US government could not possibly be so stupid as to believe its own rosy public claims as to the Shuttle's cost effectiveness, they concluded that it could only be a weapons system!  Quite naturally, in the calculus of major power players, they had to have their own.  Economic space launch had nothing to do with it.  See also Moltz [loc. cit.].

On this point, several years ago on holiday I happened to meet an ethnic Russian space cadet from one of the Baltic republics (I forget which).  He was convinced that the Shuttle's primary purpose was, indeed, weapons delivery.  For some reason, its ability to maneuver within the atmosphere was taken to be a significant military advantage.  I suspect this may have been "common knowledge" among Russian-speaking space cadets (maybe those in this forum could comment), much as it used "common knowledge" among US space cadets that the Shuttle would have worked out just fine if only the evil Air Force hadn't imposed those onerous payload and cross-range requirements.

Another system, by the way, which got as far as serious development but did not resemble the Shuttle at all was Roton.

EDIT:  Added "Roald Sagdeev".  "reached got" -> "got" in last sentence.
« Last Edit: 11/14/2018 11:09 pm by Proponent »

Offline hkultala

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Re: How would a second generation Space Shuttle look like?
« Reply #21 on: 02/05/2017 02:35 pm »
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.

Only if "shuttle-like" means 1.5 stages and heavy wings for gliding >2000 kilometers sideways from the orbital plane.

For 2-stage craft without heavy wings, things are very different.
« Last Edit: 02/05/2017 02:43 pm by hkultala »

Offline Proponent

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Re: How would a second generation Space Shuttle look like?
« Reply #22 on: 02/05/2017 03:39 pm »
The first shuttle should have looked like this (from here).  :)

I think a small version of that might have made an interesting though expensive X-vehicle.  But as an operational space shuttle, it would have doubled down on the Shuttle's major weakness:  an excess of development risk.  High-Mach-number staging of winged vehicles is not to be engaged in lightly, as Shuttle program manager Robert Thompson testified during the Columbia accident investigation (see p. 7 of the attachment).

Offline hkultala

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Re: How would a second generation Space Shuttle look like?
« Reply #23 on: 02/05/2017 03:55 pm »
The first shuttle should have looked like this (from here).  :)

I think a small version of that might have made an interesting though expensive X-vehicle.  But as an operational space shuttle, it would have doubled down on the Shuttle's major weakness:  an excess of development risk.  High-Mach-number staging of winged vehicles is not to be engaged in lightly, as Shuttle program manager Robert Thompson testified during the Columbia accident investigation (see p. 7 of the attachment).

The staging was supposed to happen at 280000 feet, practically vacuum, the wings are not doing anything at than air pressure. Much lower risk than the SRB separation of the shuttle that we got.

Offline Proponent

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Re: How would a second generation Space Shuttle look like?
« Reply #24 on: 02/05/2017 05:04 pm »
The first shuttle should have looked like this (from here).  :)

I think a small version of that might have made an interesting though expensive X-vehicle.  But as an operational space shuttle, it would have doubled down on the Shuttle's major weakness:  an excess of development risk.  High-Mach-number staging of winged vehicles is not to be engaged in lightly, as Shuttle program manager Robert Thompson testified during the Columbia accident investigation (see p. 7 of the attachment).

The staging was supposed to happen at 280000 feet, practically vacuum, the wings are not doing anything at than air pressure. Much lower risk than the SRB separation of the shuttle that we got.

High Mach-number SRB separation was a familiar technique.  High-Mach-number staging of winged vehicles was not.  No offense, but I find it difficult to take your word for it over Robert Thomson's.  If you can provide information backing up the statement, that would be interesting.

An even stronger warning about the fully-reusable two-winged-stage designs comes from Charles Donlan (acting director of the Space Shuttle program 1970-73), quoted in Heppenheimer's authoritative history of the Shuttle [p. 361]:

The two-stage fully reusables were dead, and Charles Donlan would not miss them, later declaring, "It wasn’t till the phase B’s came along and we had a hard look at the reality of what we meant by fully reusable that we shook our heads saying, ‘No way you’re going to build this thing in this century.’ As I say, ‘Thank God for all the pressures that were brought to bear to not go that route.”

Offline TrevorMonty


The vehicle needs to be either crew only with LAS or cargo only without LAS.

Offline IRobot

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Re: How would a second generation Space Shuttle look like?
« Reply #26 on: 02/05/2017 07:05 pm »
The right question is not how a 2nd gen. shuttle would look like. The right question is: "what are the requirements for a next generation space transportation system?" Maybe there is no shuttle as an answer to that requirement. Or there is a shuttle for crew, but not for cargo.

Problems start when requirements try to define the specification and design of the system.

Offline hkultala

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Re: How would a second generation Space Shuttle look like?
« Reply #27 on: 02/05/2017 07:10 pm »
The first shuttle should have looked like this (from here).  :)

I think a small version of that might have made an interesting though expensive X-vehicle.  But as an operational space shuttle, it would have doubled down on the Shuttle's major weakness:  an excess of development risk.  High-Mach-number staging of winged vehicles is not to be engaged in lightly, as Shuttle program manager Robert Thompson testified during the Columbia accident investigation (see p. 7 of the attachment).

The staging was supposed to happen at 280000 feet, practically vacuum, the wings are not doing anything at than air pressure. Much lower risk than the SRB separation of the shuttle that we got.

High Mach-number SRB separation was a familiar technique.  High-Mach-number staging of winged vehicles was not.  No offense, but I find it difficult to take your word for it over Robert Thomson's.  If you can provide information backing up the statement, that would be interesting.


In page 7 of the attachment there is absolutely nothing said about "danger of migh-mach winged vehicle separation".  You are claiming he said something he did not.

And you still do not seem to understand the difference of staging in the atmosphere and staging outside the atmosphere?



« Last Edit: 02/05/2017 07:11 pm by hkultala »

Offline Proponent

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Re: How would a second generation Space Shuttle look like?
« Reply #28 on: 02/05/2017 07:23 pm »
Only if "shuttle-like" means 1.5 stages and heavy wings for gliding >2000 kilometers sideways from the orbital plane.

For 2-stage craft without heavy wings, things are very different.

[Sorry to be so negative today, but I'm just calling it as I see it....]

Courtesy of Aerospace Projects Review, here's some data on a relatively small, straight-winged, low-cross-range shuttle design, namely Max Faget's MSC-020.  It's a two-stage design.  The payload to LEO is 20,000 lb, while the landing weight is 130,000 lb.  Even if we assume the landing weight includes 20,000 lb of return payload, the weight of the vehicle when it reaches orbit is no less than 110,000 lb.  That means the payload is just 18% of the vehicle's mass.  Hence, MSC-020's performance to higher-energy orbits would, like the Shuttle's, have been much reduced.

« Last Edit: 02/05/2017 11:41 pm by Proponent »

Offline Proponent

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Re: How would a second generation Space Shuttle look like?
« Reply #29 on: 02/05/2017 08:15 pm »
....  High-Mach-number staging of winged vehicles is not to be engaged in lightly, as Shuttle program manager Robert Thompson testified during the Columbia accident investigation (see p. 7 of the attachment).

The staging was supposed to happen at 280000 feet, practically vacuum, the wings are not doing anything at than air pressure. Much lower risk than the SRB separation of the shuttle that we got.

High Mach-number SRB separation was a familiar technique.  High-Mach-number staging of winged vehicles was not.  No offense, but I find it difficult to take your word for it over Robert Thomson's.  If you can provide information backing up the statement, that would be interesting.

In page 7 of the attachment there is absolutely nothing said about "danger of migh-mach winged vehicle separation".  You are claiming he said something he did not.

You're correct that I am incorrect on this point.  Thank you for pointing out my error.  I recalled having quoted Thompson's statement in the context of the difficulties of hypersonic staging before and, quite carelessly, did not bother to reread the text I was citing.

So, we have at this point no evidence that Thompson or his predecessor Donlan was particularly concerned about high-Mach staging.  Yet both have clearly stated that the fully-reusable designs were not a good idea.  Donlan in particular says that it was the Phase B studies that made this obvious.  The Grumman design that Oli provides above was precisely one of those Phase B studies.  Hence, we can conclude that Donlan, whom I'm sure knows far more about it than you and I put together, thought it would not have worked out well.

Offline dror

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Re: How would a second generation Space Shuttle look like?
« Reply #30 on: 02/05/2017 08:26 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.

I'd say
- F9\FH booster\s
plus a reusable 2nd stage based on a smaller raptor engine
plus Dragon2 for crew and cargo flights, a reusable fairing for LEO and a reusable tug for GEO
can be considered as the shuttle's ultimate replacement.

That's a fully reusable super heavy capable system with LAS for crew.

"If we crave some cosmic purpose, then let us find ourselves a worthy goal. "
Carl Sagan, Pale Blue Dot

Offline john smith 19

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Re: How would a second generation Space Shuttle look like?
« Reply #31 on: 02/05/2017 09:57 pm »
Shuttle mostly proved that feature creep sucks, nothing else.
A certain amount of that but the real issue was always the funding. Once you know you've got enough budget for 1 full stage and 1 full engine (and you don't trust SSTO to be viable) it gets really difficult to design a viable vehicle. Hence the Stage+RATO+drop tank design.
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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.
That was a decision in the specification. The belief that an LES was unnecessary.  But then if LES was felt to be needed maybe they would have reconsidered some of the design choices in the first place.  LES is one of those things that's a nightmare to retrofit but (relatively) easy to build in from the start. Once the design was frozen adding crew escape was effectively impossible.

BTW this follows a similar situation in the UK Vulcan aircraft. Pilot/copilot had ejector seats but the 3 crew in the rear compartment had to bail out. It seems they thought there was no point in arranging for crew escape in the middle of WWIII. In reality most crew died in accidents during the planes long (30+ years) service life. The crew in the rear compartment were also more expensive to train than the pilots.  :(
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.
I did not know that but I would note the wing layout looks remarkably like the Shuttle. OTOH there are no forces being caused by SRBs, or the ET.
Quote
- 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.
Also the Vega LV uses battery powered EMA's for main stage TVC.
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- Eliminated the human pilots and their big windows, too dangerous in the current space junk environment.
That's an interesting one.  No X37b mission has lasted less than 200 days. The design is just too small to carry people. I'm not sure anyone has mentioned anything about orbital debris damage.
Quote
- 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.
AFAIK the X37b is inside a shroud to avoid the lift forces it can generate from exceeding the control authority of the Atlas during launch, which seems to be an issue when you put winged vehicles on top of boosters that were not designed for them (starting with the Dyna Soar).
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- 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.
Nothing "mythical" about them. Buran flew AFAIK with a central LOX tank (to keep it as cold as possible) and multiple Kero tanks. NASA had flown with HT/Kero thrusters with catalytic ignition.  There is also resonance ignition.  NASA seems to have had ongoing issues with HTP in ways that other countries have not. TBF IIRC the X37b was slated to run with HTP but the only pumped rocket engine available was an original build from the 1950's.  :(
Quote
- fragile ceramic thermal protection, difficult to protect from space junk.
AFAIK X37b use the TUFI ceramic tiles which is about 10x more impact resistant than the original STS tiles.  I think the blankes are also covered in metal foil, which makes them more water resistant (although the shroud takes care of that on takeoff).
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- 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.
As always it depends on your goals. A vehicle that can be supported with limited specialist facilities has a wider range of abort options.
Quote
So I don't think a Shuttle 2.0 will exist in the foreseeable future.
I think no one is expecting NASA to fund such a vehicle.

Define the problem that needs to be solved, THEN design the solution.  Designing the solution first is just indulging fantasy...
That was my point.
[EDIT
For an interesting outsiders view of how Shuttle came to fail and then fail again people should look at this.

   ]
« Last Edit: 02/06/2017 06:08 am by john smith 19 »
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 deBASHmode

Fascinating talk. Thanks for sharing the video.
---
Shuttle hugger. Flight ops/Flight Director fangrrrrl. "I never want to hold again..."

Offline Rocket Science

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Re: How would a second generation Space Shuttle look like?
« Reply #33 on: 02/06/2017 01:39 am »
« Last Edit: 02/06/2017 01:44 am by Rocket Science »
"The laws of physics are unforgiving"
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Online brickmack

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Re: How would a second generation Space Shuttle look like?
« Reply #34 on: 02/06/2017 04:32 am »
Realistically, NASA being NASA, it would probably be more of an incremental upgrade of the existing Shuttle design. As it was, at least when they had a decent flightrate going to spread out fixed costs, it wasn't hugely more expensive than its competitors (within an order of magnitude anyway), and there was no shortage of proposed upgrades to increase performance, reduce cost, and improve safety. FFSC RS-25 would allow a bit of a thrust and ISP boost, greatly reduce thermal, mechanical, and corrosive wear on the engines (cost and safety) and eliminate multiple criticality-1 failure points within the engine. Switching from SRBs to flyback kerolox boosters would massively increase payload capacity, allow for meaningful reuse of the boosters to lower cost (unlike the RSRMs, where most of the cost was in the fuel), and make booster-phase aborts a possibility. Switching to ethanol-oxygen OMS and RCS engines would improve on-orbit maneuvering ability (higher ISP, comparable density), reduce propellant system corrosion, and simplify ground support. Etc. In addition to improving useful payload, some of these performance gains could be held back to add additional safety margin for aborts, or beef up the system (stronger structures, heavy-duty TPS, additional redundancy). They could also build a new fleet of modernized orbiters and phase out the old 3, resulting in improved safety and performance from modern designs, plus a higher achievable flightrate from having more orbiters in circulation. They'd still never be able to get the cost and performance (and definitely not safety, with that sidemount design) possible from a totally clean-sheet design (which would probably end up looking more like a LEO-optimized ITS with a cargo bay), but there was plenty of room for improvement over the original Shuttle design, and its more fitting with NASA and Congress's way of doing things IMO
« Last Edit: 02/06/2017 04:34 am by brickmack »

Offline high road

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Re: How would a second generation Space Shuttle look like?
« Reply #35 on: 02/06/2017 06:37 am »
Hm, over a dozen reactions and nobody brought up the 0th generation shuttle? Dreamchaser resembles Dyna-soar, which supposedly was what STS would have looked like if not for DoD's requirement for larger payloads.

Offline IRobot

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Re: How would a second generation Space Shuttle look like?
« Reply #36 on: 02/06/2017 09:03 am »
Switching from SRBs to flyback kerolox boosters would massively increase payload capacity, allow for meaningful reuse of the boosters to lower cost
Now you open a can of worms. If you use flyback boosters, then you don't need the 3 RD-25 on the shuttle and you don't need the massive main tank.
In the end, rethinking the whole thing, based on the concept of a flyback 1st stage, you probably end up with a single large 1st stage booster, a small 2nd stage and a very simple shuttle, with no RD-25, no umbilical, etc. Like the Buran, but with flyback 1st stage and potentially a shuttle on top instead of side mount.

Offline Proponent

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Re: How would a second generation Space Shuttle look like?
« Reply #37 on: 02/06/2017 09:29 am »
Hm, over a dozen reactions and nobody brought up the 0th generation shuttle? Dreamchaser resembles Dyna-soar, which supposedly was what STS would have looked like if not for DoD's requirement for larger payloads.

There's a big difference between Dream Chaser, HL-42, Hermes and Dyna-Soar on the one hand and the actual Shuttle and somewhat smaller versions of it, such as MSC-020, on the other.  The former are designed to carry a few people to orbit, though in some cases people can be swapped for a modest amount of payload.  The latter have much larger payloads, which are carried along with the crew.  The former are winged spacecraft completely separate from their launch vehicles.  The latter are integrated launch vehicles and spacecraft.

There certainly was discussion in the early 1970's of building a reusable Titan-launched glider, but its mission would have been entirely different from the Shuttle's.

« Last Edit: 02/06/2017 11:11 am by Proponent »

Offline R7

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Re: How would a second generation Space Shuttle look like?
« Reply #38 on: 02/06/2017 10:54 am »
1. carry big loads
2. carry large crew
3. be able to bring down whatever they bring up
4. be simple to maintain
5. be cheap to fly
6. fly very often


1. F9 FT is already close to STS LEO payload and exceeds STS GTO payload. FH expected to do twice the STS LEO payload.
2. F9 + Dragon 2 crew = STS crew
3. Proven not to be practical
4-6. Thumbs up for F9

So, I see no reason why ng 'space shuttle' couldn't look like simple slim cylinder instead of wings, lifting bodies and ETs.
AD·ASTRA·ASTRORVM·GRATIA

Offline Proponent

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Re: How would a second generation Space Shuttle look like?
« Reply #39 on: 02/06/2017 11:12 am »
I agree.  People seem to be really attached to wings and wheels.

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