Author Topic: Big Gemini  (Read 34991 times)

Offline Archibald

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Re: Big Gemini
« Reply #40 on: 05/14/2015 07:16 AM »
Interesting document, thanks for sharing. Where do you intend to publish your article ? The Space Review maybe ?

Offline Archibald

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Re: Big Gemini
« Reply #41 on: 05/14/2015 03:22 PM »
oh please... don't resist !! More seriously, with the shuttle retired, there is a lot of interest for that program early history (see Logsdon book). Just as Logsdon noted, Nixon decision of building the shuttle still has consequences today through the SLS.
"Whatif the shuttle was never build" is thus a popular alternate history scenario - and a detailed history of Big Gemini would be welcomed.

http://www.alternatehistory.com/discussion/showthread.php?t=208954
http://forum.nasaspaceflight.com/index.php?topic=26667.0
« Last Edit: 05/14/2015 03:29 PM by Archibald »

Offline RanulfC

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Re: Big Gemini
« Reply #42 on: 05/14/2015 05:50 PM »
It's hard enough writing about stuff that did get built, let alone all the stuff that didn't.

"Pass it off" to David Portree maybe?

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Blackstar

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Re: Big Gemini
« Reply #43 on: 05/18/2015 10:04 PM »
Here is what is essentially the executive summary of the Big Gemini final report, produced in August 1969. The BG timeline went like this:

-summer 1967, McDonnell Douglas proposes Big Gemini spacecraft, gets NASA study contract
-December 1967, McD reports on Big G spacecraft proposal (the document I posted earlier)
-McD gets another, much more extensive study contract (probably early 1968)
-August 1969, McD produces extensive study of Big Gemini (this document is 8 volumes, I only have this 27-page summary)
-August/October 1971, NASA finally rules out Big G as an option in favor of a winged space shuttle

I'm writing all this up. It will appear in Spaceflight eventually.

Offline Archibald

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Re: Big Gemini
« Reply #44 on: 05/20/2015 06:03 AM »
this shuttle chronology document includes information about Big Gemini

Offline Blackstar

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Re: Big Gemini
« Reply #45 on: 05/20/2015 10:33 PM »
this shuttle chronology document includes information about Big Gemini


So the last document in the set that you provided refers to the August 1969 final report on Big G. That's the document that I provided upstream here.

The second document in your set refers to initiating that study. It says that it was initiated in mid-1968, although it took a few months to actually get approved.

I'm still slightly surprised that modified Apollo CSM doesn't appear here.

Offline Archibald

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Re: Big Gemini
« Reply #46 on: 05/21/2015 06:09 PM »
I have a document that mention a six-man Apollo

Quote
SIX-MAN APOLLO SPACECRAFT
For those alternative space plans in which the shuttle operation
would be delayed or in which there would be no shuttle, a six-man modified
Apollo spacecraft would be used. This vehicle would have a gross
weight of 20,000 ib, a development cost of $1 billion, a first-unit cost
of $300 million, and a launch-operations cost of $73 million.
« Last Edit: 05/21/2015 06:10 PM by Archibald »

Offline Brovane

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Re: Big Gemini
« Reply #47 on: 05/21/2015 08:57 PM »
The thing that I find decisive for me when comparing the Apollo CSM to Big G is the logistics capability.  The Apollo CM had 218 Cubic feet of pressurized space and that was it for both crew and cargo.  The CM just didn't have a lot of space inside of it.  The Big G even with a crew of 6 has 261 cubic feet for just Cargo in the re-entry module and has a separate space for pressurized cargo space of 1571 cubic feet.  That is a lot of space which to me really makes the Big G a superior vehicle for a LEO mission to a space station.  I know the last Skylab mission in order to extend the mission they sent the Apollo CM up with basically nutrition bars stuffed in any available space they could find in the CM, because that was all they could fit in the cramped space.  Even the 5 man Apollo resulted in a design that the astronauts are stuffed inside like sardines and any landing on land you have the potentially for the upper row of couches to stroke into the astronauts sitting below. 

A interesting thought I had about "Big G" was what would have been the evolution with no Apollo program?  Would Gemini have been built as a advanced Mercury and would have Big G then evolved from Gemini still.  Basically instead of jumping to the Moon as a target during Mercury the target maybe becomes developing a Space Station.  The Saturn-1B evolves into the main launch vehicle with a Big G becoming the logistics vehicle to transport astronauts back and forth from a Space Station(s) put into orbit by a Saturn-1B. 
"Look at that! If anybody ever said, "you'll be sitting in a spacecraft naked with a 134-pound backpack on your knees charging it", I'd have said "Aw, get serious". - John Young - Apollo-16

Offline Blackstar

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Re: Big Gemini
« Reply #48 on: 05/22/2015 04:30 PM »
The thing that I find decisive for me when comparing the Apollo CSM to Big G is the logistics capability.  The Apollo CM had 218 Cubic feet of pressurized space and that was it for both crew and cargo.  The CM just didn't have a lot of space inside of it.  The Big G even with a crew of 6 has 261 cubic feet for just Cargo in the re-entry module and has a separate space for pressurized cargo space of 1571 cubic feet.  That is a lot of space which to me really makes the Big G a superior vehicle for a LEO mission to a space station.

So what made Big G possible was that McD had developed the hatch in the heatshield for Gemini B (for the MOL program). With that developed, they then proposed adding a larger crew/cargo module behind the basic Gemini. Apollo could not do that. As a result, in order to add room to Apollo you would have to add a separate pressurized module and carry it inside the SLA, in the location where the Lunar Module was carried. The Apollo CSM then separates, turns around, and hooks up to this module. There were studies of this called the Multi Mission Module, but I have not found much about it on the net.

McD was claiming that they could extend the pressurized volume of Gemini simply by adding something behind the basic Gemini. That works in theory, but it would have resulted in a much bigger heat shield and a much heavier spacecraft. Could they have made that work? They were also essentially proposing using the Gemini as the cockpit for a larger spacecraft. And this would have been more expensive.

So, yeah, Big G was on paper much more capable than Apollo. And it did, at least theoretically, have more room for growth than Apollo. But it also represented a different design path. And they would have had to add things to Big G, like the docking port and rendezvous capability, that Apollo already had.

Offline Proponent

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Re: Big Gemini
« Reply #49 on: 05/22/2015 09:42 PM »
this shuttle chronology document includes information about Big Gemini


So the last document in the set that you provided refers to the August 1969 final report on Big G. That's the document that I provided upstream here.

The second document in your set refers to initiating that study. It says that it was initiated in mid-1968, although it took a few months to actually get approved.

I'm still slightly surprised that modified Apollo CSM doesn't appear here.

Apollo does get a brief mention -- albeit by its manufacturer -- on page 9 of the PDF provided by Archibald.
« Last Edit: 05/22/2015 09:43 PM by Proponent »

Offline Proponent

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Re: Big Gemini
« Reply #50 on: 05/22/2015 09:59 PM »
Might not a "Big A" version of Apollo been possible?  Shrink the SM -- is delta-V and consumables capabilities were far in excess of what was needed for LEO logistics -- and lengthen it to provide additional cargo and crew capability.  There was, after all, a 1966 proposal from North American for a land-landing version of Apollo carrying six.

Offline Blackstar

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Re: Big Gemini
« Reply #51 on: 05/22/2015 10:34 PM »
Might not a "Big A" version of Apollo been possible?  Shrink the SM -- is delta-V and consumables capabilities were far in excess of what was needed for LEO logistics -- and lengthen it to provide additional cargo and crew capability.  There was, after all, a 1966 proposal from North American for a land-landing version of Apollo carrying six.

Apollo was already over-powered and too big for low Earth orbit. It had the SIM bay, and you could reduce the tanks and even the engine. So yes, shrink the SM functions and then open it up with cargo space. But that's all unpressurized. To get a pressurized volume, they would have had to go with the hatch through the heat shield route.

Online Bob Shaw

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Re: Big Gemini
« Reply #52 on: 05/22/2015 10:39 PM »
Actually, Big G would have had a more benign atmospheric entry than the standard capsule, so far as I can see; it would have had a significantly greater volume and a lower density, making the whole thing work better as it scaled up.

Offline Patchouli

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Re: Big Gemini
« Reply #53 on: 05/23/2015 01:20 AM »

Apollo was already over-powered and too big for low Earth orbit. It had the SIM bay, and you could reduce the tanks and even the engine. So yes, shrink the SM functions and then open it up with cargo space. But that's all unpressurized. To get a pressurized volume, they would have had to go with the hatch through the heat shield route.
A fully LEO optimized Apollo probably would be very similar to the Soviet TKS spacecraft which Big G was similar to as well.
Ironically several configurations of the  Shuttle where it carried a pressurized module in the cargo bay was functionally similar to the capability Big G would have offered.

Offline Archibald

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Re: Big Gemini
« Reply #54 on: 05/23/2015 07:51 AM »
Quote
A fully LEO optimized Apollo probably would be very similar to the Soviet TKS spacecraft which Big G was similar to as well.

Spot on. Alexei Lenov called the TKS "our Apollo" for good reasons.

Offline RanulfC

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Re: Big Gemini
« Reply #55 on: 05/26/2015 03:37 PM »
A interesting thought I had about "Big G" was what would have been the evolution with no Apollo program?  Would Gemini have been built as a advanced Mercury and would have Big G then evolved from Gemini still.  Basically instead of jumping to the Moon as a target during Mercury the target maybe becomes developing a Space Station.  The Saturn-1B evolves into the main launch vehicle with a Big G becoming the logistics vehicle to transport astronauts back and forth from a Space Station(s) put into orbit by a Saturn-1B. 

IIRC Apollo was "conceived" as a basic LEO vehicle with lunar applications and became lunar specific due to the requirement given NASA. Gemini was conceived as something quick-and-dirty to use between when Mercury ended and Apollo began to gain experience in the operations that were going to be required for those lunar operations. If JFK had decided to build a Space Station instead of going to the Moon I doubt very much that Gemini would have even been built and that Apollo would be a very different vehicle than it was.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Blackstar

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Re: Big Gemini
« Reply #56 on: 05/26/2015 04:34 PM »
IIRC Apollo was "conceived" as a basic LEO vehicle with lunar applications and became lunar specific due to the requirement given NASA.

I think that the ability to fly circumlunar was there at the start.

Online the_other_Doug

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Re: Big Gemini
« Reply #57 on: 05/26/2015 04:51 PM »
A interesting thought I had about "Big G" was what would have been the evolution with no Apollo program?  Would Gemini have been built as a advanced Mercury and would have Big G then evolved from Gemini still.  Basically instead of jumping to the Moon as a target during Mercury the target maybe becomes developing a Space Station.  The Saturn-1B evolves into the main launch vehicle with a Big G becoming the logistics vehicle to transport astronauts back and forth from a Space Station(s) put into orbit by a Saturn-1B. 

IIRC Apollo was "conceived" as a basic LEO vehicle with lunar applications and became lunar specific due to the requirement given NASA. Gemini was conceived as something quick-and-dirty to use between when Mercury ended and Apollo began to gain experience in the operations that were going to be required for those lunar operations. If JFK had decided to build a Space Station instead of going to the Moon I doubt very much that Gemini would have even been built and that Apollo would be a very different vehicle than it was.

Randy

Apollo was conceived as the next manned spacecraft after Mercury.  It was first conceived in 1959, IIRC, as a three-man vehicle with "circumlunar capability."  In other words, the original idea was for Apollo to be a circumlunar spacecraft.  The idea was that you design a spacecraft capable of swinging around the Moon.  Then you add another propulsion stage and that vehicle can go into, and come out of, lunar orbit.  Add a landing/takeoff stage, and that vehicle can land on the Moon and return.

That was the kind of incremental thinking NASA was doing in terms of going to the Moon when Apollo was first conceived.  It was from the first thought of as a circumlunar vehicle.  In fact, the circumlunar mission was the primary mission I can recall being mentioned for it.  Apollo was not conceived as primarily a LEO vehicle, with lunar applications grafted on later, once Kennedy decided to point America towards the lunar landing.

As for the three-man crew, the idea was that such a vehicle would need a lot of tending and maintenance in-flight, so a submarine-like work schedule to maintain one crew person awake and on duty at all times required a minimum of three crew.  They were thinking of Mercury-times-three, which would indeed need a lot of crew attention.

You're certainly correct that Gemini came into being as a "bridge" program, originally conceived as Mercury Mark II, a simple upgrade to Mercury (perhaps not even increasing the crew complement), to be used in proving out and rehearsing rendezvous and EVA techniques that Apollo would need.  Mercury Mark II was being discussed as early as 1959, but was really only made possible by the lunar landing commitment, when it became clear that we needed to develop and prove those techniques well before Apollo could be ready to fly.  Of course, it was proposed as a modest extension to Mercury, that would cost well less than a billion dollars overall, and ended up as a major manned spaceflight program with a total program cost of more than two and a half billion.  But that's how groundbreaking development programs tend to run.

I believe that had Apollo not been set the lunar landing goal, you might well have seen a Mercury Mark II of some kind, but it might have been limited to adding an equipment module to, and modestly redesigning, the Mercury spacecraft, and flying it on an Atlas-Agena or on a Titan.  But you likely wouldn't have seen the same type of Mark II spacecraft that ended up evolving into Gemini.
-Doug  (With my shield, not yet upon it)

Offline RanulfC

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Re: Big Gemini
« Reply #58 on: 05/26/2015 09:01 PM »
Sorry didn't mean to give the impression that the "circumlunar" was tacked on it was there from the beginning but that the Apollo spacecraft was (as noted) already the "follow-on" to Mercury. Currently reading the book "John F. Kennedy and the Race to the Moon" and it along with everything else I've seen pretty much shows that "Mercury Mark II" wasn't Gemini and Gemini was in support of, not competition with Apollo.

I highly suspect that if something LEO-ish had been chosen for a "goal" instead of lunar that Apollo itself would have turned out VERY unlike what it was.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Blackstar

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Re: Big Gemini
« Reply #59 on: 05/26/2015 09:14 PM »
Sorry didn't mean to give the impression that the "circumlunar" was tacked on it was there from the beginning but that the Apollo spacecraft was (as noted) already the "follow-on" to Mercury. Currently reading the book "John F. Kennedy and the Race to the Moon" and it along with everything else I've seen pretty much shows that "Mercury Mark II" wasn't Gemini and Gemini was in support of, not competition with Apollo.

There were some proposed intermediary steps there. I don't know who was pushing what, but there were proposals for extended Mercury missions and that's where the support package with consumables behind the heat shield came from. I think very quickly that evolved into Mercury Mark II with a two-person crew. For all intents and purposes MMII was Gemini. They were adding capabilities and requirements all the time, so I don't think there's really a clear delineation between MMII and Gemini.

You are right that Gemini was in support of Apollo. But McDonnell was a hungry company, and they were pitching Gemini variants soon after they had the contract. That included the circumlunar Gemini. You can imagine how this would quickly annoy NASA officials. They had an approved lunar program and they didn't need another contractor undercutting their decision.

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