X-33/VentureStar - What really happened

[LittleBird]

I'm not opposed to a bit of thread-drift if a thread has been doing on a long time, and I know how much you enjoy going off-topic on threads, but a mod warned earlier about going off-topic on this thread.

OK, I had perhaps misread the mod's intervention as being specifically about the 737 MAX which is a plane, not a spaceplane. My bad, as you say over there. Is there a good other place to put Mark's X24 comments  ? I ask because although not X33 related directly they are of enduring historic interest, I'd have thought.

[JAFO]

As usual, NASA and OMB were talking two different languages. NASA wanted a vehicle capable of flying multiple times a week and putting payloads into orbit for pennies on the dollar, OMB wanted a safer and cheaper replacement for the Shuttle. It's basically the same argument NASA and OMB had in the early 1970s, when OMB tried to guide NASA towards an HL-20 sized vehicle launched on a Titan III variant instead of the massive 40+ flights a year fully reusable system NASA was trying to sell the White House, which eventually ended up compromising on the Space Shuttle we know.

Don't forget the role politics played, too.

In 1969, he accepted President Nixon’s appointment to serve as executive secretary of the National Aeronautics and Space Council, charged with determining America’s post-Apollo role.

Anders, still mulling both approaches, vividly recalls a call from H.R. “Bob” Haldeman, Nixon’s chief of staff, bluntly asking which option would provide more aerospace jobs in California. When he gave the obvious answer — the big shuttle — that was it. Click, decision made.
The shuttle program was launched, the jobs were secured and NASA embarked on what Anders calls a four-decade-long detour. The shuttle was a spectacular vehicle, with an equally spectacular price tag: It wound up increasing the cost of spaceflight tenfold. “That is a 100-fold error,” Anders says, with clear disgust.

https://www.seattletimes.com/pacific-nw-magazine/with-a-view-from-beyond-the-moon-an-astronaut-talks-religion-politics-and-possibilities/

[Jim]

I once worked with Kathy Thornton, who was on the first Hubble Servicing Mission and did a lot of training with Hubble and was also an engineer. She explained a lot of things that had to be designed into Hubble to make it serviceable, and they include a lot of things you might not think about. For instance, all the high power wiring had to be specially designed, because you could not electrocute an astronaut who was touching the spacecraft. There were also things like sharp edges and even little things like screws and bolts that had to be specially designed so they did not snag a spacesuit. The spacecraft also had to be designed so that it could be safed before it was grappled or touched--didn't want to have electricity running through it or a transmitter active and pointing at an astronaut's head.

Certainly a lot of stuff. I'm reminded of one of the servicing studies of Shuttle that noted failing to use captive fasteners for the LRU's in various areas significantly  complicated servicing. I can see dedicated hardware to safe various systems would add some mass (and take up some radio channels) but TBH most of sounds more like a bit more care in design and mfg. 
The one big PITA I could see was replacing all the wiring looms with unmounted plugs with rigidly located plugs, and adding matching plugs on the ORU's, along with hardware to let them slid out, along with the captive fasteners that can be opened by a person in a suit.

Had on-orbit servicing become SOP I could see people people moving from 3-string to 2-string redundancy so once the primary failed it would be time to add that satellite to the deorbit-from-GEO-for-attention list.

But that never happened. 

Again, there are very few spacecraft of note in LEO.   Most are in higher orbits.  If HST was not to be shuttle serviced, it would have been sent to L2 like most space observatories.  HST had to deal with earthshine in its target inanition to a warmer environment.

[john smith 19]

Again, there are very few spacecraft of note in LEO.   Most are in higher orbits.  If HST was not to be shuttle serviced, it would have been sent to L2 like most space observatories.  HST had to deal with earthshine in its target inanition to a warmer environment.

True, but something that people forget about the Space Transportation System was it was designed to be a system of parts and Space Tug was a key enabler of this approach.

No Space Tug anything above LEO would need to keep a propellant reserve to lower orbit for Shuttle servicing. Which never happened. 

[Jim]

True, but something that people forget about the Space Transportation System was it was designed to be a system of parts and Space Tug was a key enabler of this approach.

No Space Tug anything above LEO would need to keep a propellant reserve to lower orbit for Shuttle servicing. Which never happened. 

Not really.  It was just more flawed thinking.  It wasn't realistic to be reusable.  The Space Tug could not have done GEO delivery and return much less escape missions.  And there were space tugs - IUS, PAM, TOS.

[LittleBird]

True, but something that people forget about the Space Transportation System was it was designed to be a system of parts and Space Tug was a key enabler of this approach.

No Space Tug anything above LEO would need to keep a propellant reserve to lower orbit for Shuttle servicing. Which never happened. 

Not really.  It was just more flawed thinking.  It wasn't realistic to be reusable.  The Space Tug could not have done GEO delivery and return much less escape missions.  And there were space tugs - IUS, PAM, TOS.

So granted that quite a few unrealistic (for now, or for ever) aspirations of the original STS had been abandoned by turn of century at the latest, what were the missions that Venturestar still aspired to-apart from the personnel to space stations that pretty much all shuttles have shared ?

[Spiceman]

From a Shuttle payload bay in LEO, it takes approximately 4 km/s to climb to GEO. Return is a bit more complicated: aerobraking can remove (for "free") some delta-v from 4 km/s down.

Do we have somewhere, NASA 1972 space tug delta-v roundtrips to GEO ?

But even 5 km/s or 6 km/s would be daunting.

Next parameter is the mass of the GEO comsat to be delivered. They started at less than 1 mt in the early 1970's and ended at almost 7 mt late in the career of Ariane 5, that is in the 2000's.
So let's suppose a 3 mt comsat, to be delivered to GEO by a reusable space tug then returning to the Shuttle payload bay.
And remember the Shuttle was supposed to carry 30 mt but ended at 23 mt (Chandra - from memory).
Then the best possible specific impulse is the RL-10B-2 466 seconds, while hydrolox mass fraction is 0.90 for small and medium stages (big S-II managed 0.92).

Once all these parameters and limits considered, fact it was difficult to pack a reusable space tug + comsat (with or without aerobraking) inside the Shuttle 23 mt payload envelope.

I do know that they considered an aerobraking space tug in the 1980's for Freedom, but I can't remember whether the 1972 space tug would return to LEO Shuttle payload bay propulsively.

Or maybe did they consider only GTO (2.5 km/s, one-way) for that reusable space tug ? the comsat filling the gap to GEO with its own kick stage or internal propulsion system ?

[Jim]

Next parameter is the mass of the GEO comsat to be delivered. They started at less than 1 mt in the early 1970's and ended at almost 7 mt late in the career of Ariane 5, that is in the 2000's.

Ariane never direct injected into GEO.  Delta IV Heavy was 6750 kg direct

[john smith 19]

Not really.  It was just more flawed thinking.  It wasn't realistic to be reusable.  The Space Tug could not have done GEO delivery and return much less escape missions.  And there were space tugs - IUS, PAM, TOS.

Indeed, except they were 1-use 1-way  They were all solids.

Reaction Engines pointed out that if you place the RLV at the right altitude you can use a resonance orbit technique where the RLV does n orbits (about 8-10 IIRC) while the US does a single orbit from LEO to GEO, leaving the payload to fire a circularising burn.

I find it very hard to believe this hasn't been spotted before  Obviously you have to set the altitude of the RLV part quite carefully, and since GEO is quite well defined phasing is tricky, but it does mean there would not need to be 4 burns by the stage to stop and start at either orbit. And of course the payload has to do some work but it still seems both viable and a new win from my PoV.

[Jim]

Not really.  It was just more flawed thinking.  It wasn't realistic to be reusable.  The Space Tug could not have done GEO delivery and return much less escape missions.  And there were space tugs - IUS, PAM, TOS.

Indeed, except they were 1-use 1-way  They were all solids.

Reaction Engines pointed out that if you place the RLV at the right altitude you can use a resonance orbit technique where the RLV does n orbits (about 8-10 IIRC) while the US does a single orbit from LEO to GEO, leaving the payload to fire a circularising burn.

I find it very hard to believe this hasn't been spotted before  Obviously you have to set the altitude of the RLV part quite carefully, and since GEO is quite well defined phasing is tricky, but it does mean there would not need to be 4 burns by the stage to stop and start at either orbit. And of course the payload has to do some work but it still seems both viable and a new win from my PoV.

not really, the upper stage is still really over sized.

[Will O Wisp]

So granted that quite a few unrealistic (for now, or for ever) aspirations of the original STS had been abandoned by turn of century at the latest, what were the missions that Venturestar still aspired to-apart from the personnel to space stations that pretty much all shuttles have shared ?

Pretty much everything. All US Gov launches. All commercial launches. All EU/Japan launches. The VentureStar would be the primary launch vehicle for the entire free world.

There are a lot of political/economic issues that would have made this very difficult, but VentureStar was sold as making the cost of space access so cheap, it would blow though a lot of these barriers. As VSECOTSPE mentioned earlier in the thread, there's a lot of skepticism if that would have been possible.   

[Spiceman]

Somewhat like a spaceborne 747 ? I mean, many airlines across the world bought the 747 because it provided unique capabilities, unmatched for decades. That's what they hoped to achieve for space programs, with the VentureStar ?

[LittleBird]

So granted that quite a few unrealistic (for now, or for ever) aspirations of the original STS had been abandoned by turn of century at the latest, what were the missions that Venturestar still aspired to-apart from the personnel to space stations that pretty much all shuttles have shared ?

Pretty much everything. All US Gov launches. All commercial launches. All EU/Japan launches. The VentureStar would be the primary launch vehicle for the entire free world.

There are a lot of political/economic issues that would have made this very difficult, but VentureStar was sold as making the cost of space access so cheap, it would blow though a lot of these barriers. As VSECOTSPE mentioned earlier in the thread, there's a lot of skepticism if that would have been possible.

Thanks.


Was there a published mission model for Venturestar at any point, analogous to the famous Shuttle ones ? It’d make interesting resding I’d guess.

[Jim]

So granted that quite a few unrealistic (for now, or for ever) aspirations of the original STS had been abandoned by turn of century at the latest, what were the missions that Venturestar still aspired to-apart from the personnel to space stations that pretty much all shuttles have shared ?

Pretty much everything. All US Gov launches. All commercial launches. All EU/Japan launches. The VentureStar would be the primary launch vehicle for the entire free world.

There are a lot of political/economic issues that would have made this very difficult, but VentureStar was sold as making the cost of space access so cheap, it would blow though a lot of these barriers. As VSECOTSPE mentioned earlier in the thread, there's a lot of skepticism if that would have been possible.

Thanks.


Was there a published mission model for Venturestar at any point, analogous to the famous Shuttle ones ? It’d make interesting resding I’d guess.

no, because it wasn't a gov't program and no one had put money down on it for a ride.

[Spiceman]

The X-33 was to be a Mach 15 forerunner to a Mach 25 VentureStar SSTO. Except the demonstrator took weight and the mach numbers dropped and dropped again, to Mach 12, then even lower.
Since VentureStar was never build, there was no Shuttle like flight manifest, ever.

[LittleBird]

The X-33 was to be a Mach 15 forerunner to a Mach 25 VentureStar SSTO. Except the demonstrator took weight and the mach numbers dropped and dropped again, to Mach 12, then even lower.
Since VentureStar was never build, there was no Shuttle like flight manifest, ever.

OK, thanks Jim and Spiceman. In that case can I back up a little and ask if there were published corporate studies loosely analogous to the NASA-funded Mathematica study of about 1971, making assumptions about what payloads Venturestar would have been intended to fly, and what its economics were supposed to be ? Or was it really as case of "build it and they will come" ?

And while we are here, what is the rather curious-looking satellite in this NASA image from the Wiki page for Venturestar ?

[Spiceman]

My bet & guess would be: Space Based Solar Power demonstrator.  And I concur about your "bring it and they will come" hypothesis.

It's the old "airline to space" paradigm. Ju-52 & Ford Trimotors could fly passengers, but with next to zero profit. Boeing 247, DC-2, DC-3 and a few other look alike were the first to turn a meagre profit flying passengers - on short haul airways.
 Clearly the big deal was transtlantic crossings, but it took three steps - Constellation, 707, 747 - to make the whole thing safe enough and profitable (and even then, post 9-11-2001 losses wiped out in the next two years, all the profits made by airlines since 1946 !)

Playing that analogy, ELVs were seen as Ju-52s, and it was hoped SSTOs like VentureStar could leap at least to the 707 level. Back in the (shuttle) early days Max Faget called his pet shuttle the DC-3. Says a lot.

Back in the 1990 satellites constellations were all the rage, not for broadband Internet but as an alternative to a seemingly frail GSM across borders - from space. But GSM ultimately beat the odds and triumphed, and (as an example) my country of France embarked into a colossal ground-based-antenna buildup, putting mobile phone antennas at every street corner and every high rise building. From memory, the effort lasted 5 to 8 years, broadly from 1995 into the early 2000s.
And thus satphones lost that battle at the same time - and then the dot-com bubble finished the whole craze by the fall of 2000. Only Kistler and one of the three big constellation survived (never remind which one - think it is Iridium, still going strongly nowadays).

I think X-33 and X-34 could be seen as NASA trying to kickstart RLVs that could then ride the satphone constellation craze. Just like F9 and SH-Starship flight manifests are force-fed 42 000 starlinks spacecraft.

Iridium, Teledesic, Globalstar were the three major efforts, but just like today with Kuiper and the chinese there were a bunch of other competitors, with the usual varied degree of seriousness (ARCA early seeds were probably planted back then... shudders).

[Jim]

And while we are here, what is the rather curious-looking satellite in this NASA image from the Wiki page for Venturestar ?

Solar Electric or Solar Thermal drive

[LittleBird]

And while we are here, what is the rather curious-looking satellite in this NASA image from the Wiki page for Venturestar ?

Solar Electric or Solar Thermal drive

Thanks, makes sense. I couldn’t see why a spinner seemed to have what looked to me like two big antennae sticking out of the “wrong” end, but that theory is plausible.

[john smith 19]

Iridium, Teledesic, Globalstar were the three major efforts, but just like today with Kuiper and the chinese there were a bunch of other competitors, with the usual varied degree of seriousness (ARCA early seeds were probably planted back then... shudders).

IRL Teledisc never happened and it was Orbcomm (launched on Pegasus solids that IIRC made the best running).
BTW all went through Chapter 11 and still exist. The joke about Iridium (Element 77) shrank to 66 satellites, which is actually "Dysprosium" 
IOW it's possible to make a satellite comms business and (eventually) make a profit it at.

But boy is it tough.