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God has no intention of setting a limit to the efforts of man to conquer space.

---Pius XII

Geminimania

The Gusmobile could have conquered space - faster, better cheaper - browse through the many might-have-been Geminis!

Hello: gemi160.gif. Spacecraft: Gemini. Crew Size: 2.
The concept was to enlarge the Mercury capsule's basic design to accommodate two crew, provide it with orbital manoeuvring capability, use existing boosters to launch it and an existing upper rocket stage as a docking target. The latest aircraft engineering was exploited , resulting in a modularised design that provided easy access to and changeout of equipment mounted external to the crew's pressure vessel.
In many ways the Gemini design was ahead of that of the Apollo, since the project began two years later . The crew station layout was similar to that of the latest military fighters; the capsule was equipped with ejection seats, inertial navigation, the pilot's traditional 8-ball attitude display, and radar. The escape tower used for Mercury was deleted; the propellants used in the Titan II launch vehicle, while toxic, corrosive, poisonous, and self-igniting, did not explode in the manner of the Atlas or Saturn LOX/Kerosene combination. The ejection seats served as the crew escape method in the lower atmosphere, just as in a high-performance aircraft. The seats were also needed for the original landing mode, which involved deployment of a huge inflated Rogallo wing (ancestor of today's hang gliders) with a piloted landing on skids at Edwards Dry Lake. In the event, the wing could not be made to deploy reliably before flights began, so the capsule made a parachute-borne water landing, much to the astronauts' chagrin.
All around the Gemini was considered the ultimate 'pilot's spacecraft', and it was also popular with engineers because of its extremely light weight. The capsule allowed recover of a crew of two for only 50% more than the Mercury capsule weight, and half of the weight per crew member of the Apollo design. The penalty was obvious - it was christened the 'Gusmobile' since diminutive Gus Grissom was the only astronaut who was said to be able to fit into it. The crew member was crammed in, shoulder to shoulder with his partner, his helmet literally scrunched against the hatch, which could be opened for space walks. With the crew unable to fully stretch out unless an EVA was scheduled, living in the capsule was literally painful on the long missions (Gemini 5 and 7). Getting back into the seat and getting the hatch closed in an inflated suit in zero gravity was problematic and would have been impossible if the spacewalking astronaut was incapacitated in even a minor way.
Early on it was proposed that the Gemini could be used for manned circumlunar or lunar missions at a fraction of the cost and much earlier than Apollo. Truth be told, a Gemini launched atop a Titan 3E or Saturn IVB Centaur could have accomplished a circumlunar flight as early as 1966 and, using earth orbit rendezvous techniques, a landing at least a year before Apollo. But the capsule, while perhaps suited as a ferry vehicle to space stations, would have been quite marginal for the lunar mission due to the cramped accommodation. But mainly NASA was fully committed to the Apollo program, which was grounded on a minimum three man crew and minimum 10,000 pound command module weight.
At a cost of 5% of the Apollo project, NASA staged twelve flights, ten of them manned, in the course of which the problems of rendezvous, docking, and learning how to do work in a spacesuit in zero-G were tackled and solved. It is said that not much of this was fed back to Apollo, since the two projects had completely different sets of contractors and there was little cross-fertilisation in the rendezvous and docking areas. But it is undeniable that important issues in regard to working in zero-G were discovered and solved and both flight and ground crews gained experience that would make the Apollo flights successful.
Gemini was to have continued to fly into the 1970's as the return capsule of the USAF Manned Orbiting Laboratory program. However with the MOL's cancellation in 1969 work at McDonnell came to an end and the last models of the finest spacecraft ever built were scrapped.
Full Details of the Gemini spacecraft and its subsystems can be seen at:
Gemini Spacecraft Description
Gemini Subsystem Development Diaries

Hello: mol480.jpg. Spacecraft: MOL. Crew Size: 2.
After cancellation, some of the reconnaissance systems ended up in later KH series satellites, and some of the manned experiments were accomplished on Skylab.

Hello: gemcent.gif. Spacecraft: Gemini-Centaur. Crew Size: 2.

At its birth Gemini was known as the Mercury Mark II programme. NASA was already committed to the three-man Apollo spacecraft and considered Gemini an interim spacecraft to test rendezvous, docking, and EVA techniques before Apollo was available. But NASA's James Chamberlin and McDonnell Aircraft considered Gemini as a viable competitor to Apollo for the circumlunar and lunar landing missions. Such proposals might have been welcomed by the later 'cheaper, better, faster' NASA. But in 1961, as a direct challenge to the Apollo project and Lyndon Johnson's dream of a Southern High Technology Crescent, they were anathema.

The original August 14, 1961 Mercury Mark II program plan went like this:

Date	Flight	Description
Mar 1963	Gemini 1	Unmanned orbital
May 1963	Gemini 2	Manned orbital
Jul 1963	Gemini 3	7-day manned orbital
Sep 1963	Gemini 4	7-day manned orbital
Nov 1963	Gemini 5	Agena docking
Jan 1964	Gemini 6	14-day primate orbital
Mar 1964	Gemini 7	Agena docking
May 1964	Gemini 8	14-day primate orbital
Jul 1964	Gemini 9	Agena docking
Sep 1964	Gemini 10	Agena docking
Nov 1964	Gemini 11	Centaur docking, boost to high Earth orbit
Jan 1965	Gemini 12	Centaur docking, boost to high Earth orbit
Mar 1965	Gemini 13	Centaur docking, boost to Lunar flyby
May 1965	Gemini 14	Centaur docking, boost to Lunar flyby

The Centaur would be launched atop a Titan II booster. The lunar Gemini spacecraft would have weighed 3,170 kg, an extra 270 kg over the basic rendezvous Gemini. The difference consisted of a backup inertial navigator and additional heat shielding for re-entry at 11 km/sec instead of 8 km/sec. This program was estimated to put an American around the moon for only $ 60 million more than the basic $ 356 million program. An even more aggressive alternative, a nine-flight program, was promised to cost only $ 8.5 million more than the basic program and fly around the moon in May 1964! This first attempt to fly Gemini to the moon was quickly suppressed, and a revision of the plan was issued only a week later, with all mention of lunar flights deleted.

Hello: bigmock2.jpg. Spacecraft: Big Gemini. Crew Size: 9.
By the end of 1966 NASA's Gemini program was nearing its conclusion and the design phase of the USAF Manned Orbiting Laboratory (MOL) project was nearly finished. McDonnell-Douglas had a large manned spacecraft engineering team, built up over eight years on the Mercury, Gemini, and MOL programs that was facing dissolution. At the same time both USAF and NASA had funded space station projects. The USAF's MOL and the NASA's Apollo Applications Program Orbital Workshop (later Skylab) were to fly in 1969-1974. Both USAF and NASA were planning even larger follow-on stations - the USAF LORL and NASA MORL.
The capability of existing spacecraft (Apollo CSM, Gemini) for manned resupply missions to these stations was severely limited. In the 1970-1980 period, it appeared that at least a dozen launches would be required for logistics purposes for the Apollo Applications Program alone. MOL and the AAP workshop would require 3 to 6 flights a year, each flight delivering a crew of two or three, with 1 to 7 tonnes of cargo being sent up and up to 0.6 cubic meters of cargo being returned. Planned late 1970's stations would have crews of 6 to 24, requiring a resupply craft that could deliver up to 12 passengers and 12 tonnes of payload 6 to 14 times a year, returning up to 7 cubic meters of cargo each time. Big G could provide such a capability by 1971, using Gemini technology applied to Gemini and Apollo hardware, with minimum interference to the higher priority Apollo lunar landing program.
McDonnell Douglas conceded that the initial flights to Orbital Workshop 1 (then planned for 1970) would have to be supported by the Apollo CSM. However Big G could be available in 1971 to provide improved crew and cargo versatility for Orbital Workshop 2 and USAF MOL resupply.
Big G would consist of the following modules:
- Launch escape tower - the LES developed for the Apollo program would be used for Big-G.
- Big G re-entry module - This was based on the Gemini B re-entry module developed for the USAF MOL program. The Gemini B's fully integrated flight cockpit, environmental control system, and electronic system installations would be retained. However the Gemini B re-entry module conical structure would be extended to 154 inches (3.91 m) diameter (the same as the Apollo service module) to provide a large passenger compartment. This compartment could accommodate up to ten additional passengers or a mix of passengers and cargo - a capacity over twice as great as the Apollo command module at the same total re-entry vehicle mass. The standard configuration proposed for NASA had a crew of six plus substantial cargo return capability. The environmental control system for the passengers and the communication system were located under the floor of the passenger compartment. The existing hatch in the Gemini-B bulkhead would be retained to allow the pilot and co-pilot access to the passenger compartment.
- Retrograde module - This module, tapering from 154 inches to 180 inches (4.57 m) diameter at its base, would house the solid fuel de-orbit rocket motors, separation rockets, and water and oxygen supplies.
- Manoeuvring and cargo module - This module included propulsion for orbital manoeuvring, electrical power, pressurised and unpressurised volumes for cargo, a pressurised pass-through tunnel, an Apollo docking probe assembly, and a control station for controlling the docking manoeuvre. Unlike Gemini or Apollo, Big G would dock by its aft end with the space station (the same approach was used in the Soviet TKS resupply spacecraft). This module would vary greatly in size and mass according to the launch vehicle used. In the USAF configuration the manoeuvring and cargo module was cylindrical and 180 inches in diameter, for mating to the planned Titan 3G launch vehicle. A truncated version with less than a tenth of the payload could be used with the MOL Titan 3M booster. For NASA use the module was conical, flaring to 260 inch (6.61 m) diameter for mating to the S-IVB upper stage of a Saturn INT-20 or Solid motor/S-IVB launch vehicle.
It was possible to transfer crew and cargo from Big-G to the space station without extra-vehicular activity. A pressurised tunnel led from the passenger compartment to the cargo area, and another tunnel to the docking probe.
Big G used the "packaged return capability" of the Gemini-B. This included "sealed-until-needed" oxygen supply, RCS system, and retrograde and separation motors. These features, compared to Apollo, improved crew safety by assuring the spacecraft could endure extended in-orbit quiescent storage while docked to the space station.
As another alternative (obviously not favoured by McDonnell Douglas) the Big G re-entry capsule could be used with an Apollo Service Module and the Apollo Applications Program Multi-Mission Module (a palletised cargo carrier mounted, like the Lunar Module, behind the SM, with which Big G would have to dock and extract from the spent booster).
Total mass of the Big G would depend on the launch vehicle. The Titan 3M version would total 15,600 kg, delivering 9 crew and 2,500 kg of supplies to MOL in a 480 km, 50 degree inclination orbit. The NASA INT-20 version weighed 47,300 kg and could deliver 9 crew and 27,300 kg of payload to the same orbit. The Titan 3G configuration would have an orbital insertion mass of 59,000 kg in a 28.5 degree, 150 x 220 km orbit.
McDonnell's sales pitch was summarised as follows:
- NASA needed an economical logistics vehicle for the Apollo Applications Program
- USAF was interested in a similar logistics vehicle for MOL
- Both NASA and USAF had studies in work for advanced logistics systems for the late 1970's (ILRV - this would eventually become the space shuttle), but nothing existed for the early to late 1970's flights
- A modified Apollo or Big G were the only logical contenders for the role
- Big G was preferable to a modified Apollo because:
  - Big G would not interfere with the high-priority lunar program
  - Big G could more economically accomplish projected AAP logistics requirements by utilising existing developed equipment
  - Big G could be developed on a cost-sharing basis by NASA and USAF together, reducing costs to both Agencies and providing equipment commonality
  - Big G would utilise an experienced, available, and successful industrial team
Big G was not to be. Even at the time the concept was originated both NASA and USAF manned space projects were being cut back. Within 18 months, MOL would be cancelled, and AAP would be limited to using only spacecraft and boosters surplus to the moon landing program. Soon thereafter the shuttle became the only funded space project for the 1970's, and all space station work was abandoned. The Gemini spacecraft - and the American push to rapidly exploit the cosmos - were dead.

Hello: gemferr.jpg. Spacecraft: Gemini Ferry. Crew Size: 2.
In 1962 NASA funded studies with several contractors on Operations and Logistics for Space Stations. McDonnell's study was dated 20 March 1963 and proposed three alternatives, all of which could be boosted by either a Titan 3M or Saturn IB Launch Vehicle, and all of which would be equipped with aft-mounted docking systems:
- Two-crew Gemini, relatively unmodified, with a cargo module
- Modified Gemini with a stretched re-entry vehicle (later fully developed into the Big-Gemini)
- New winged spaceplane, capable of accommodating two crew plus four passengers

Hello: dagena.jpg. Spacecraft: Gemini Agena Target Vehicle.
The Gemini-Agena Target Vehicle design was an adaptation of the basic Agena-D vehicle using the alternate Model 8247 rocket engine and additional program-peculiar equipment required for the Gemini mission. This GATV was divided into:
- The program-peculiar forward auxiliary section. This section consisted of the auxiliary equipment rack, the McDonnell Aircraft Company-furnished docking-adapter module, and the clamshell nose shroud.
- The Agena-D forward and mid-body sections. The Agena-D forward section housed the main equipment bay, and the mid-body contained the main fuel and oxidizer tanks which supplied propellants through a feed and load system for the main engine. (3) the program-peculiar aft section. The Model 8247 multi-start main engine and the smaller Model 8250 maneuvering and ullage orientation engines were located in this section.
Orbital length of the GATV was approximately 26 feet. Vehicle weight-on-orbit was approximately 7200 lb. This weight included propellants still remaining in the main tanks and available for Model 8247 engine operation after the Agena achieved orbit.
The Gemini-ATV propulsion system consisted of the following:
- Model 8247 rocket engine, also known as XLR-81-BA-13, and its controls, mount, gimbals, and titanium nozzle extension
- Pyrotechnically operated helium-control valve (POHCV) and associated pressurization plumbing
- Fuel and oxidizer feed and load system, including propellant tanks, vents, and fill quick disconnects
- Propellant isolation valves (PIV's)
- All associated pyro devices and solid-propellant rockets.
The XLR-81-BA-13 engine thrust chamber was an 80-percent bell-shape with an expansion ratio of 45:1. This thrust chamber assembly performed satisfactorily throughout a gimbaling orientation of plus 5 deg in a square pattern from the associated planes, with a gimbal acceleration of 30 rads/sec/sec. The nozzle was regeneratively cooled up to the point at which the area ratio was 13.3: I. The remaining portion of the nozzle (13.3:1 to 45:1) was a radiation-cooled titanium extension.
The propulsion system was designed to inject the GATV into an orbital path which has an altitude varying between 161 nautical miles (nm) and 87 nm when measured at a latitude of 28. 34 deg. A minimum of five main-engine burns were available to complete the mission requirements; one burn was required for injection into orbit and four subsequent burns were available to perform orbital plane and phase changes, as required and selected from ground stations or from the spacecraft. All launches took place from AMR Pad 14.
Once the GATV was in orbit, the PPS provided the thrust necessary for the following maneuvers :
- Adjusting the orbits so that they were coplanar and making the radius of one apside of the Agena orbit equal to the rendezvous radius
- Circularizing the Agena at the rendezvous radius and proceeding to an inertial location which was a point lying on the line of the apsides of the catch-up orbit
- At the initial location of the injection point, transfering the Agena to a catch-up orbit for placing the vehicle at the rendezvous point when specified.
The XLR-8I-BA-13 was a liquid bi-propellant rocket engine with a minimum capability of five starts and a demonstrated capability of fifteen starts under vacuum conditions. This rocket engine consisted of the following major components:
- Thrust-chamber assembly
- Multiple-restart assembly
- Turbine-pump assembly
- Overspeed shutdown electronic-gate and cable assembly
- Turbine-exhaust duct
- Propellant manifolds
- Thrust-chamber nozzle extension
Fuel used was unsymmetrical dimethylhydrazine (UDMH); oxidizer used was inhibited red fuming nitric acid (IRFNA). The propulsion system provided the thrust necessary to place the GATV into a selected orbit and to accomplish major orbital changes. A minimum of five starts was available for performing these maneuvers.
The Gemini-ATV Status Panel (ASP), was mounted on the forward end of the Target Docking Adapter of the Agena Target Vehicle where it was visible to the astronauts in the Gemini spacecraft during and after the docking maneuver. The panel displayed information on the status and safety of the Agena propulsion, guidance, electrical power, and docking systems. Originally, only eight Agena parameters were to be displayed in the Gemini spacecraft; however, the number of parameters increased to the point that the spacecraft no longer had the space or weight capability to accomodate them. Accordingly, the panel was placed on the Target Docking Adapter. The ASP system consisted of a display panel with nine display lights and three analog dials and the necessary circuitry which was distributed throughout the Gemini-ATV. When not in use, this system was normally de-energized in order to save power; however, the PPS and SPS Time Remaining Clocks were energized whenever the PPS or SPS engines fire. Three of the twelve parameters displayed on the ASP panel, indicated PPS status and three indicated SPS status. The Primary Propulsion System displays were as follows:
- PPS Burn Time Remaining Clock
- "MAIN" Red Light
- "MAIN" Green Light
The Secondary Propulsion System displays were as follows:
- SPS Burn Time Remaining Clock
- "SEC HI" Green Light
- "SEC LO" Green Light
Requirements received from the astronauts stated that a dimming circuit must be added to the ASP system, because the panel lights were found to be too bright when the spacecraft docked with the GATV on the night side of the earth. Consequently, a dimming circuit was added to reduce or increase the brightness to the desired level. The dimming circuit functions on all lights except MAIN Red which was always bright when "ON". In order to improve reliability, two lamps were incorporated in each indicator light.

Hello: gemexmis.jpg. Spacecraft: Extended Mission Gemini. Crew Size: 2.
The crew would transfer from the Gemini to the miniature space station via an inflatable airlock.

Hello: gemland2.jpg. Spacecraft: Gemini Lunar Surface Rescue Spacecraft. Crew Size: 3.

An extended Gemini reentry capsule had a passenger compartment for up to three rescued astronauts. The basic LSRS design used three modified Apollo Lunar Module descent stages for lunar orbit insertion, lunar landing, and lunar ascent.

An alternate configuration used two Apollo Service Modules and a repackaged LM descent stage. The first Service Module completed the translunar injection maneuver begun by the S-IVB stage; the second SM accomplished lunar orbit insertion and then functioned as a 'lunar crasher' stage, bringing the Gemini to just above the lunar surface. The Gemini and the third transearth-lunar landing stage would then hover to a landing near the stranded lunar module. The same final stage then boosted the Gemini capsule into a transearth trajectory.

In the wake of the Apollo fire, NASA reexamined many safety aspects of the Apollo project. The Apollo mission profile was inherently risky, and the likelihood of a crew being stranded in lunar orbit or on the lunar surface was relatively high. McDonnell returned to a concept first studied in 1962 - the use of Gemini as a Lunar Rescue Vehicle. Use of the Gemini B capsule, then in construction for use with the US Air Force's Manned Orbiting Laboratory, with various combinations of Apollo lunar module stations, would provide a rescue vehicle that could pick up Apollo astronauts stranded in lunar orbit or on the lunar surface. Three variant rescue schemes were studied:

McDonnell summarised the advantages of the various schemes, as contrasted with use of Apollo hardware for the same task, in the following matrix:

Lunar Orbit Rescue Lunar Surface Survival Shelter Lunar Surface Rescue

Gemini Apollo Gemini Apollo Gemini Apollo

Vehicle Description Modified Gemini & repackaged LM Ascent Stage Apollo CSM Modified Gemini & Modified LM Descent Stage Modified SM & Modified LM Modified Gemini, repackaged LM Ascent Stage & Modified LM Descent Stages Apollo CSM & LM

Mission Unmanned to lunar orbit, three man direct return Unmanned to lunar orbit, three man direct return Unmanned to lunar surface, 28 day quiescent storage, 28 day 2-man operation Unmanned to lunar surface, 30 day manned operation Unmanned to lunar orbit, 30 day unmanned quiescent stay, 2 man direct return Unmanned to lunar orbit, LM to lunar surface, LM to lunar orbit, 2 man return

Advantages
Uses developed equipment
No new development
Can be accomplished with current acquisitions
Extension of lunar orbit vehicle
Similar to planned post-Apollo exploration shelter
Extension of lunar orbit/shelter vehicle
No rendezvous required
Direct return
No new development
Same as existing mission

Disadvantages
New spacecraft development
Possibility of same failure mode
New spacecraft development
Requires modifications to existing hardware
New spacecraft development
Rendezvous required
May be difficult to automate transpose docking

Recommendations Do not develop-rescue capability too limited. Greatest emergency potential at lunar surface Do not develop - need for shelter and total number of Saturn launches reduced by providing an on-station backup return capability Modify to a 'Universal' Rescue Vehicle by improving capability to cover three-man cases

McDonnell concluded that an unmanned Gemini 'Universal Lunar Rescue Vehicle' could be developed that would perform all three tasks. The Gemini capsule would be extended to allow up to three rescued Apollo crew members to be returned. Such a craft could rescue the entire Apollo crew at any point along the Apollo mission profile. Some sketches appear to show a two-man Gemini crew in addition to three crew couches in the Gemini capsule extension. The unspoken point was that the Saturn V was in fact large enough to land men on the moon using the direct-ascent method. Use of lunar orbit rendezvous was only necessary because of NASA's adherence to the 6 tonne, three-crew Apollo command module design. The 2 tonne Gemini capsule, even in a form stretched to accommodate three to five crew, could accomplish a direct landing on the moon using Apollo components.

This last attempt to resuscitate Lunar Gemini failed as well. At that point in the Apollo program cut-backs already had begun. No funds would be forthcoming to build additional launch vehicles and spacecraft beyond those already purchased. There was definitely no money to provide a rescue capability, using either Apollo or Gemini hardware.

Hello: gemluorv.jpg. Spacecraft: Gemini LORV. Crew Size: 3.

McDonnell summarised the advantages of the various schemes, as contrasted with use of Apollo hardware for the same task, in the following matrix:

Hello: gemlusss.jpg. Spacecraft: Gemini Lunar Surface Survival Shelter. Crew Size: 2.

McDonnell summarised the advantages of the various schemes, as contrasted with use of Apollo hardware for the same task, in the following matrix:

Hello: gemobsvy.jpg. Spacecraft: Gemini Observatory. Crew Size: 2.

Hello: gemparag.jpg. Spacecraft: Gemini Paraglider. Crew Size: 2.

Hello: gemrescu.jpg. Spacecraft: Rescue Gemini. Crew Size: 5.
The basic Gemini reentry module was extended to 120 inches (3.05 m) diameter to provide a passenger compartment for up to three rescued crew. The same concept would eventually be used for Big Gemini.

Hello: gemwin1.jpg. Spacecraft: Winged Gemini. Crew Size: 2.
The spacecraft was designed for launch by the standard Titan 2 Gemini Launch Vehicle. Unlike the ballistic Gemini, winged Gemini was not designed to maneuver in orbit (launch on a Titan 3A or 3C with a transtage would be required for that capability). Separation from the launch vehicle was made by 2 x 260 kgf solid motors; attitude control in orbit was provided by 8 x 45 kgf bipropellant thrusters at the base of the vehicle; retrofire was initiated by 5 x 1165 kgf solid rocket motors.

Hello: gemxport.jpg. Spacecraft: Gemini Transport. Crew Size: 2.
In 1962 NASA funded studies with several contractors on Operations and Logistics for Space Stations. McDonnell's study was dated 20 March 1963 and proposed three alternatives, all of which could be boosted by either a Titan 3M or Saturn IB Launch Vehicle, and all of which would be equipped with aft-mounted docking systems:
- Two-crew Gemini, relatively unmodified, with a cargo module
- Modified Gemini with a stretched re-entry vehicle (later fully developed into the Big-Gemini)
- New winged spaceplane, capable of accommodating two crew plus four passengers

Hello: gemxstg1.gif. Spacecraft: Gemini - Double Transtage. Crew Size: 2.
A declassified memorandum from the Director, Gemini Systems Engineering, documents a June 24, 1965 meeting at Manned Spaceflight Center between the contractors' corporate heads and highest NASA management. At this meeting the companies provided a detailed proposal to launch a refurbished, modified Gemini around the moon by April 1967 for $ 350 million. The Gemini would have 521 kg of mass deleted, half of it by removing the solid fuel retrograde rockets used to initiate re-entry (the liquid fuel Orbital Manoeuvring System would be reengineered to increase its reliability). The Titan 2-launched Gemini would rendezvous and dock with a Titan 3C-launched 'Double Transtage'. The Double Transtage consisted of an unmodified first Transtage that would place itself and a second Transtage into low earth orbit. The first Transtage retained the navigation and manoeuvring systems necessary to move the assembly to the rendezvous orbit with Gemini. The second Transtage would be stripped of unnecessary equipment (the orbital manoeuvring system) but was equipped with an Agena-type docking collar.
After docking with the Double Transtage, the first Transtage would be cast off and the second Transtage would propel the Gemini into a circumlunar trajectory. The flights themselves, assuming go-ahead was given in September 1965, would follow immediately after the last Gemini flight. In December 1966 a Titan 3C would drive a 2450 kg circumlunar Gemini capsule to 11 m/s re-entry velocity to verify the heat shield design. This would be followed by a February 1967 manned qualification flight in earth orbit. A manned Gemini would dock with a Double Transtage and be propelled into a high orbit and re-entry speed. In April the sequence would be repeated, this time the Gemini being sent by Transtage into a loop around the moon.
The author of the memo thought that Gemini extension efforts would be better directed towards proving space station assembly techniques and procedures using Gemini and Agena. He also thought the schedule and cost estimates to be over-optimistic. The reaction of top NASA management was more categorical. Pete Conrad managed to stir Congressional interest, but NASA administrator James Webb informed them that any extra funds Congress cared to appropriate for such a project would be better spent accelerating the Apollo program. After further internal struggles, Conrad finally got NASA approval for the Agena on his Gemini 11 flight to boost him into a record 1,570 km orbit. This high flight was the only remnant of lunar Gemini.

Hello: gemlulun.jpg. Spacecraft: Gemini LOR. Crew Size: 2.

In September 1961 NASA's James Chamberlin came up with a plan to use a Gemini capsule to land two men on the moon and return them safely to earth at a cost 1/20 of that of the Apollo project. The key was the use of the technique of lunar orbit rendezvous and a bare-bones, open cockpit lunar module. This would weigh 4,372 kg in the storable propellant version or 3,284 kg in the cryogenic Lox/LH2 version (calculated propellant loads 3,500 kg and 2,200 kg, respectively). The total mass to be injected into an escape trajectory toward the moon would be no more than 13,000 kg, one fifth of the 68,000 kg planned for the Nova-boosted direct-lunar landing approach favoured at that time. At this mass, instead of Nova, a Saturn C-3 launch vehicle could be used. The Gemini flight schedule would have been delayed by a year in order to develop a more capable spacecraft. However by launching every 45 days instead of every 60 days Gemini would still put an American on the moon by January 1966:

Date	Flight	Description
Titan 2 Launches

Mar 1964	Gemini 1	Unmanned orbital
May 1964	Gemini 2	Manned orbital
Jun 1964	Gemini 3	7-day manned orbital
Aug 1964	Gemini 4	14-day manned orbital
Sep 1964	Gemini 5	Agena docking
Nov 1964	Gemini 6	Agena docking
Dec 1964	Gemini 7	Agena docking
Feb 1965	Gemini 8	Centaur docking, boost to high Earth orbit
Mar 1965	Gemini 9	Centaur docking, boost to high Earth orbit
May 1965	Gemini 10	LM docking
Jun 1965	Gemini 11	LM docking
Jul 1965	Gemini 12	LM docking
Sep 1965	Gemini 13	Centaur docking, boost to Lunar flyby
Oct 1965	Gemini 14	Centaur docking, boost to Lunar flyby

Saturn C-3 Launches

Nov 1965	Gemini 15	Manned Lunar orbital
Jan 1966	Gemini 16	Manned Lunar landing

The lunar module would have been launched separately by Titan II for the three Earth orbital docking missions. This moon landing project was projected to cost $ 584 million 'plus the cost of two Saturn C-3's'.

Chamberlin was actually the first member of the Space Task Group (STG) to advocate lunar orbit rendezvous (LOR) as a method for reaching the moon. Earlier efforts through 1960 and 1961 by Robert Hoboult and other engineers at Langley to interest STG in the method had been seen as the impractical musings of theorists. Chamberlin and McDonnell Aircraft did not fall in this category. They saw clearly that separating the re-entry and lunar landing functions allowed optimised spacecraft designs for each role, and solved many of the intractable engineering problems the direct-ascent advocates were struggling with.

Chamberlin made one last effort at the end of September to interest STG in including lunar Gemini as part of an "Integrated Apollo Program". This involved the same flight schedule as advocated earlier, but with the cost estimate now firmed up at $ 706 million (including the Saturn boosters!), and the lunar module mass cut to 1,800 kg. NASA brass still rejected the lunar aspects of the plan, but told STG to go ahead with negotiations with McDonnell, Martin, and Lockheed for the spacecraft and boosters. Chamberlin submitted the revised plan without lunar flights on October 27, and this was approved as the basis for project Gemini.

The actual Gemini project as flown was over a year late to the original optimistic plan. This was due to delays in development of both the Titan 2 launch vehicle and the Gemini paraglider landing system. The pivotal 14-day flight actually came in December 1965 versus January 1964 in the first Mercury Mark II proposal and August 1964 in the September 1961 plan.

Date	Flight	Description
Apr 1964	Gemini 1	Unmanned booster orbital test; boilerplate spacecraft.
Jan 1965	Gemini 2	Unmanned suborbital test of spacecraft
Mar 1965	Gemini 3	Manned orbital
Jun 1965	Gemini 4	4-day manned orbital
Aug 1965	Gemini 5	8-day manned orbital
Dec 1965	Gemini 7	14-day manned orbital
Dec 1965	Gemini 6	Rendezvous with Gemini 7 (Agena target failed to orbit)
Mar 1966	Gemini 8	Agena docking
Jun 1966	Gemini 9	Agena docking
Jul 1966	Gemini 10	Agena docking
Sep 1966	Gemini 11	Agena docking
Nov 1966	Gemini 12	Agena docking

It is possible to estimate when Chamberlin's Gemini moon landing would have actually occurred based on the actual delays to Gemini. It must be considered that the time necessary to develop the Saturn C-3 could not have been much less than that actually taken for the C-5 (the final December 1961 C-3B configuration differed from the C-5 only in the propellant loading in each stage and in having three F-1 engines in the first stage as opposed to five in the C-5). Therefore, with perfect hindsight, if Gemini had been selected in lieu of Apollo, the actual final program would have looked about like this:

Date	Flight	Description
Titan 2 Launches
Apr 1964	Gemini 1	Unmanned booster orbital test; boilerplate spacecraft.
Jan 1965	Gemini 2	Unmanned suborbital test of spacecraft
Mar 1965	Gemini 3	Manned orbital
Jun 1965	Gemini 4	4-day manned orbital
Aug 1965	Gemini 5	8-day manned orbital
Dec 1965	Gemini 7	14-day manned orbital
Dec 1965	Gemini 6	Rendezvous with Gemini 7 (Agena target failed to orbit)
Mar 1966	Gemini 8	Agena docking
Jun 1966	Gemini 9	Agena docking
Aug 1966	Gemini 10	Centaur docking, boost to high Earth orbit
Oct 1966	Gemini 11	Centaur docking, boost to high Earth orbit
Nov 1966	Gemini 12	LM docking
Jan 1967	Gemini 13	LM docking
Feb 1967	Gemini 14	LM docking
Mar 1967	Gemini 15	Centaur docking, boost to Lunar flyby
Apr 1967	Gemini 16	Centaur docking, boost to Lunar flyby

Saturn C-3 Launches
Aug 1967	Gemini 17	Unmanned test of Saturn C-3
Feb 1968	Gemini 18	Unmanned Lunar orbital test
Oct 1968	Gemini 19	Manned Lunar orbital
Dec 1968	Gemini 20	Manned Lunar landing

So in the end, the first lunar landing would have been moved up by six months at best. There would have been a cost savings, but again analysis of the detailed cost breakdowns for Apollo indicate the savings would have been on the order of 'only' $ 4 billion out of the NASA $ 18 billion project share. So in retrospect it would seem that NASA's management was correct, for the Apollo missions flown were much more capable than a Gemini-based approach would have been.

Spacecraft: Gemini EMU.

Spacecraft: Gemini Pecan.

Spacecraft: Gemini AM.

Spacecraft: Gemini EM.

Spacecraft: Gemini RM. Crew Size: 2.

Spacecraft: Gemini B RM. Crew Size: 2.
Many changes were made from the original NASA Gemini, including:
- Internal systems were containerised and designed for long term orbital storage
- The cockpit layout was completely redesigned and new instruments were developed
- The cant of the ejection seats were changed in order to make room for the hatch in the heat shield between the crew's shoulders
- After the Apollo fire, cabin atmosphere was changed to Helium-Oxygen in place of pure oxygen. At launch, the crew breathed pure oxygen in their suits while the cabin was filled with pure helium. During ascent, oxygen from the suits slowly brought the cabin atmosphere up to the helium-oxygen content of the station itself.
- In order to handle higher energy re-entries from polar orbit, the heat shield was increased in diameter, so that it actually stuck out a bit from the base of the re-entry vehicle.
- The OAMS manoeuvring thrusters of the NASA Gemini were deleted. Spacecraft orientation in orbit was handled by the forward RCS thrusters.
Gemini B would have been flown alone, without an active MOL, unmanned, in two qualification test launches of the Titan 3M booster prior to the first manned MOL flight.

Spacecraft: Big Gemini RV. Crew Size: 9.

Spacecraft: Big Gemini CM.

Spacecraft: Gemini Ferry CM.

Spacecraft: Gemini Ferry AM.

Spacecraft: Gemini Ferry RM. Crew Size: 2.

Spacecraft: Big Gemini AM.

Spacecraft: Gemini LSRS RM. Crew Size: 3.

Spacecraft: Gemini LSRS AM.

Spacecraft: Gemini LSRS LM.

Spacecraft: Gemini LSRS LOIM.

Spacecraft: Gemini LORV RM. Crew Size: 3.

Spacecraft: Gemini LORV SM.

Spacecraft: Gemini Lunar RM. Crew Size: 2.

Spacecraft: Gemini LSSS SM.

Spacecraft: Gemini LSSS LM.

Spacecraft: Gemini B AM.
Changes to the Gemini adapter module included:
- A transition tunnel led from the hatch in the heat shield of the Gemini B to the MOL pressurised quarters.
- In the absencd of the equipment module, the adapter module was longer in order to flare out to meet the 3.05 m diameter of the MOL.
- The OAMS manoeuvring thrusters of the NASA Gemini were deleted. Spacecraft orientation in orbit was handled by the forward RCS thrusters.
- The number of solid propellant retrofire motors was increased from four to six. These served double-duty: for deorbit of the Gemini B and as abort rockets for separation of the Gemini from the enormous Titan 3M in case of launch vehicle failure.

Spacecraft: Gemini Lunar Lander. Crew Size: 2.
Following the preliminary decision to proceed with the lunar orbit rendezvous technique for the Apollo lunar landing mission, there was one final effort to return to the simpler direct landing approach. Lunar orbit rendezvous would require a three-man Apollo capsule, in order for a crew of two to reach the lunar surface while the third crewmember tended the waiting Apollo in lunar orbit. But if the objective was to land two men on the moon, why use the three-man Apollo capsule? Why not use either the two-man Gemini capsule, or a reduced size two-man Apollo-shaped capsule to land directly on the moon? Such a spacecraft could be propelled toward the moon on a single launch of the Saturn C-5 rocket, just like the LOR version.
McDonnell, builders of the Mercury and Gemini spacecraft, were given the contract to make a study of the alternate approach. The result showed it was indeed feasible, at less cost, risk, complexity, and time, then the LOR 3-man Apollo. The only problem was that the existing work done on the North American three-crew Apollo would have to be scrapped, and either a modified Gemini or a new two-crew Apollo developed in its place. Wiesner, Kennedy's science adviser, was an enthusiastic about the approach. NASA, North American, and the competitors for the lunar module contract were distinctly less interested. Webb, the NASA Administrator, finally got the idea spiked once and for all. Although Gemini lunar landers would be advocated again, as rescue vehicles, or whenever Apollo ran into development trouble, they would never get past the very preliminary paper stage.
Major ground rules for the study were:
- Launch vehicle was the Saturn C-5, injecting 40,800 kg to a lunar transfer orbit.
- Mission duration was eight days (two and one-half days flight time to moon, one day on lunar surface plus one day contingency, two and one-half days return time plus one day contingency) plus seven days post landing (one day habitable environment plus six days survivable environment ).
- Both cryogenic and noncryogenic propulsion systems were to be considered. The final configuration used a LOX/LH2 RL10-powered stage for the major lunar crasher stage, and N2O4/MMH storable propellants for the lunar landing and ascent stages.
- Atmosphere was 5 psi normal, 3.5 psi emergency, 100% oxygen.
- First operational flight during the first half of calendar year 1967 was assumed.
Three modifications of the Gemini design were considered for the direct lunar landing:
- Lunar Gemini I used the as-then-configured, 14 day, earth orbital Gemini command module and service equipment with only those changes considered necessary to effect compatibility with the direct flight lunar landing mission. This included the paraglider for landing at an airstrip at the United States on return. A number of methods for providing the crew with a field of view of the lunar surface during the landing maneuver appear feasible and attractive from the standpoint of minimizing changes to the basic Gemini configuration. The most promising of these were: l) use of the existing Gemini window with an erectable external mirror to provide a downward field of view with the crewman lying in the normal position and 2) use of an auxiliary transparent canopy (or use of the Gemini hatch in open position with cabin depressurized). In the latter method, the crewman was in a rotated (semi-prone) position and viewed the lunar surface directly. A combination of (1) and (2) were selected for Lunar Gemini I with the R.H. crewman provided a mirror and the L.H. crewman provided a transparent canopy through which he may observe the lunar surface while rotated in the present Gemini seat. In conjunction with this position, instruments necessary for control of the lunar landing were provided in an extendable panel located in the service module within the crewman's field of view. Necessary controls were provided adjacent to the seat sides.
- Lunar Gemini II utilized the then-alternate Gemini 26 m diameter single parachute recovery system in lieu of the paraglider system and associated landing gear. The weight and space savings thus effected permitted the installation of improved navigation and telecommunications capability while increasing the margin for potential weight growth. Earth landings were effected in water and, in the event of emergency recovery over land, the crew utilized the ejection seats to separate from the capsule and terminate the descent with personal parachutes. Crew lunar landing vision provisions are the same as described for Lunar Gemini I.
- Lunar Gemini III was modified to accept a tower-mounted rocket launch escape system in lieu of ejection seats, thus providing an improved launch abort capability. The paraglider and landing gear were replaced by three 22 m diameter parachutes with normal earth recovery being effected over water. Means were provided for emergency earth recovery over land either through bail-out capability with personal parachutes or, by the use of shock attenuating couches to make land impacts in the command module tolerable. The use of positionable shock attenuated couches in lieu of ejection seats permitted the incorporation of a crew "sit-up" lunar landing capability facilitated by a direct view through a large window in the left-hand hatch.
Weight summary was as follows:
- Command Module: 2387 to 2551 kg Service Module Equipment: 534 to 553 kg Spacecraft Weight Margin ("to make total come out the same"): 465 to 659 kg Service Module: 10,064 kg Terminal Landing Module: 2735 kg Retrograde Module: 24,393 kg Launch Escape System: net 1,179 kg on Configuration 3 Landing Gear Fairing: 634 kg Gross Weight at Launch 41,377 kg to 42,556 kg Less (1% effective) Jettisonable Items: 616 to 1740 kg Effective Launch Weight 40,761 kg to 40,816 kg
The major Gemini Guidance and Navigation components utilized were the inertial system and computer. Additions for Lunar Gemini I included an auto sextant and the Apollo tracking and landing radars (total system weight - 155 kg). Additions for Lunar Gemini II and III included the Apollo sextant/telescope, the Apollo tracking and landing radars, and a roll momentum wheel for use during manual navigation (total system weight - 166 kg).
The power system provided was essentially the same as that used in the l4-day Gemini with some off-loading of fuel cell reactants and the addition of increased sequential control provisions. A detailed electrical load analysis indicated that the mission requirements were 660 watts average for Gemini I and 880 watts average for Lunar Gemini II and III. Sufficient fuel was provided for the full 8 day mission, two days of which were contingency.
Conventional spacecraft structures are employed in all modules, following the proven materials and concepts demonstrated in the Mercury and Gemini designs. Primary structure of each module consists of a semimonocoque shell with reinforcements around cut-outs and fittings to distribute localized loads. Titanium was used as the basic shell material in all modules except the service module where beryllium sheet was used for the structural radiator shell.
Re-entry heat protection was conservatively designed for a shallow long range re-entry or a 20 g structural limit re-entry, whichever resulted in the greater protection requirements. The ablative material was MAC Thermorad Shield S-3 elastomeric composite. Nominal thermophysical properties were used in the calculations and a 1.15 factor was applied to predicted heating rates. The total ablative material design weight is 232 kg for Lunar Gemini I and II, and 221 kg for Lunar Gemini III.

Spacecraft: Gemini - Saturn I. Crew Size: 2.
This could either be flown in the long gap between the end of Gemini and the start of Apollo/Saturn IB flights, or as a contingency to beat the Russians around the moon if Apollo suffered severe delays. An Agena, Transtage, or Centaur upper stage would have been added to the Saturn I in order to boost Gemini to the moon. But Von Braun and others were not interested. They definitely did not want Congress getting wind of anything that could undermine support for Apollo. On June 8 NASA headquarters issued instructions that "any circumlunar mission studies related to the use of Gemini will be confined to in-house study efforts" and prohibiting issuance of contracts to McDonnell to pursue the matter.

Spacecraft: Gemini - Saturn IB. Crew Size: 2.
The manned portion was a modified earth-orbit Gemini. The aft modules would be retained, but with the retrorockets removed. The retro module space would be used to install Apollo-type lunar distance communications, navigation, and test equipment. Deployable DSIF omni-directional and parabolic antennae would deploy from the aft modules to support lunar-distance communications. To handle re-entry from lunar distances, several modifications were necessary. The capsule's heat shield would be beefed up, and the Rene 41 corrugated shingles of Gemini's skin would be replaced with ablative shingles. The load of attitude control propellant for the capsule's reaction control system was substantially increased. Additional strap-down gyros and solar sensor packages would be added to provide navigation system redundancy. The ejection seats would be deleted and a Mercury-style launch escape tower added. The then-planned Rogallo wing recovery system would be used to glide to the Gemini to a runway landing on US territory after return from the moon. To handle the scientific payload, a camera compartment was added to the nose below the parachute/Rogallo wing housing. The Gemini spacecraft modified in this way had on on-orbit mass of 3955 kg as compared to the 3207 kg of the earth-orbit version.
The circumlunar version used the Saturn IB launch vehicle. This would put the Gemini mated to a partially-fuelled Centaur upper stage in low earth parking orbit. The Centaur would fire, sending the Gemini on a loop around the moon.
The scientific equipment would consist of a modest camera array installed in the nose of the spacecraft. This consisted of a long focal-length telescope, to which were attached a telephoto camera, a 40 degree field-of-view mapping camera, a 180 degree field-of-view panoramic camera, and two 16 mm film cameras. The tube of the telescope would be jettisoned with the nose compartment during parachute deployment, but the telescope base, mirror, and film cassettes were retained. The cameras would be used to film the moon during the relatively brief flyby period. This began 96 minutes before closest approach to the lunar surface, with the spacecraft 9700 km from the lunar surface. For 92 minutes the spacecraft could film in detail the Apollo primary landing site on the Sea of Tranquillity and the those portions of the unseen back side of the moon that were in daylight (the flight would be timed for the sun angle to be 45 degrees at the Sea of Tranquillity). Closest approach to the moon would be 160 km. Beginning 36 minutes after closest approach, at a distance of 4500 km from the surface, the sunlit portion of the moon would again appear, and remaining film could be used for reconnaissance of the area around Copernicus crater.

Spacecraft: Gemini - Saturn V. Crew Size: 2.
The lunar orbit version required an Agena stage to provide the delta-V for lunar orbit insertion and trans earth injection. The 1.52 m-diameter Agena was enclosed in an inverted conical fairing to both transmit thrust loads to the Gemini and provide thermal protection during the coast to the moon. Alternatively, a propulsion module based on a repackaged Apollo Service Module propulsion system, as had been proposed two years earlier for a lunar-landing version of Gemini, could be used. This raised the translunar injection mass of the spacecraft to 11,182 kg, well above the capability of a Saturn IB or Titan 3C, but only a quarter that of a Saturn V. The launch vehicle was unspecified, but could only have been a Saturn V used on an early test mission. The mission profile would have involved a 68 hour flight from low earth orbit to lunar orbit, a 24 hour lunar mapping mission in a 10 nm x 80 nm lunar orbit, and a 68 hour return flight. The scientific equipment would consist of a modest camera array installed in the nose of the spacecraft. This consisted of a long focal-length telescope, to which were attached two narrow-field stereo mapping cameras, a wide field mapping camera, a panoramic camera, and two 16 mm film cameras. The film was not accessible by the astronauts, being stored in a film vault shielded against radiation in the nose of the spacecraft. The camera compartment would protrude from the stub nose of the Gemini after parachute deployment.
The manned portion was the same as the circumlunar version, a modified earth-orbit Gemini. The aft modules would be retained, but with the retrorockets removed. The retro module space would be used to install Apollo-type lunar distance communications, navigation, and test equipment. Deployable DSIF omni-directional and parabolic antennae would deploy from the aft modules to support lunar-distance communications. To handle re-entry from lunar distances, several modifications were necessary. The capsule's heat shield would be beefed up, and the Rene 41 corrugated shingles of Gemini's skin would be replaced with ablative shingles. The load of attitude control propellant for the capsule's reaction control system was substantially increased. Additional strap-down gyros and solar sensor packages would be added to provide navigation system redundancy. The ejection seats would be deleted and a Mercury-style launch escape tower added. The then-planned Rogallo wing recovery system would be used to glide to the Gemini to a runway landing on US territory after return from the moon. To handle the scientific payload, a camera compartment was added to the nose below the parachute/Rogallo wing housing. The Gemini spacecraft modified in this way had on on-orbit mass of 3955 kg as compared to the 3207 kg of the earth-orbit version.

Spacecraft: Gemini Satellite Inspector. Crew Size: 2.
Rendezvous with an Unmanned Satellite
Description - The objective of the flight was to rendezvous with a noncooperative target, namely the Pegasus satellite, photograph the meteoroid puncture panels to corroborate telemetered data, and remove and return a piece of one of the panels by extravehicular activity, if possible.
The basic mission plan was to: (i) inject into a low orbit coplanar with the Pegasus orbit for gross catch-up, (2) transfer open loop, based on tracking data, to a slow catch-up orbit slightly lower than the Pegasus orbit, and (3) perform a closed loop rendezvous after contact was made. An alternate plan would be to first rendezvous with an Agena and then use the Agena propulsion for the open loop transfer to the slow catch-up orbit. The Agena would then be discarded and a second closed loop rendezvous performed with Pegasus. The alternate was operationally complicated and would not be considered unless more extensive analysis shows the basic plan unworkable or undesirable.
After rendezvous was completed, a slow pass was to be made to photograph the meteoroid puncture panels. After the photograph run was completed, the two craft would be "docked" and a crewman would secure the specimen of the panel by EVA.
Technical or Scientific Benefit - The greatest benefit of the mission was the accomplishment of rendezvous with a non-cooperative target, thus opening the possibility of obtaining additional data using spacecraft with this capability. The information returned from the Pegasus should provide, in addition to substantiating data received from it by telemetry, direct information of the effects of meteoroid impacts on structures for use in future designs.
Effect on US Space Program - The experience obtained would be directly applicable in the areas of satellite data retrieval, resupply, maintenance, repair, and recovery. The knowledge of meteoroids arid their impact with a spacecraft would be considerably increased, which would benefit the Apollo and other future space programs. The mission would provide information for DOD directly applicable in the areas of satellite interception, inspection, and surveillance.
Prestige Value - The return of a piece of a spacecraft from orbit, a feat which had yet to be accomplished, would demonstrate advanced space skills and carry implications of an ability to exercise access to any orbiting object at will.
Performance Feasibility - Preliminary analysis showed that if the OAMS was augmented by the addition of two sets of tanks and four 45 kgf thrusters, and if some of the additional delta-V capability was used to extend the Gemini Launch Vehicle payload capability, rendezvous with Pegasus was possible. Analysis showed that 390 kg of the 845 kg of propellant loaded in the OAMS at liftoff could be used to inject the Gemini into a 160-185 km orbit. The remaining 455 kg of propellant would be sufficient to complete the mission. The weight change associated with the change in spacecraft configuration and propellant loading, and the use of eight retrorockets for retrograde from the Pegasus orbit, were considered in the analysis.
Extensive analysis of: (i) injection performance, (2) rendezvous with a spacecraft in an elliptic orbit, and (3) of retrograde and re-entry would be required to more definitely establish the delta-V capability of the spacecraft and the delta-V required for rendezvous and retrograde.
Cost Feasibility - The first unit cost was estimated to be $19.75 million with each additional unit costing $1.75 million, plus the coat of the spacecraft and launch vehicle.
Schedule Feasibility - It was estimated that a Gemini could be modified in approximately 20 months.
Operations Feasibility - The effect of the changes required, (OAMS augmentation and possible computer program changes) would make little difference in over-all ground operations. Flight operations would be similar to those for Gemini and were expected to be straightforward.
Radiation hazard over the South Atlantic might require flight operations at the Pegasus altitudes to be performed when the orbit did not enter this tone, according to a radiation analysis conducted using two different radiation models.
Impact on Gemini Program - The impact of the Pegasus mission on the Gemini Program would be principally that of sustaining a fairly sizeable engineering effort to accomplish the propulsion system configuration changes and to insure the integrity of the associated structural changes. In addition, changes to checkout equipment end AGE would have to be made. The magnitude of these changes were not ascertained to date.
Aside from the actual hardware changes, the suitability of: (i) the Gemini scheme of rendezvous when in elliptic orbit, (2) the re-entry control scheme when re-entering from high orbits, and (3) the launch guidance back-up for controlling an OAMS augmented injection would have to be established. If any of the three were to give unsatisfactory performance, a new scheme would have to be devised, programmed, and procedures revised.

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Last update 8 January 2006.

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