Conrad was much taken with the notion of a Gemini trip around the Moon.5 Even after Webb dismissed the scheme, he still wanted to take Gemini as far as it would go. When he was named as command pilot, he recalled, "it didn't look like . . . [a high altitude] flight was ever going to get done on Gemini." Conrad saw a heaven-sent opportunity to resurrect the idea when he calculated that he could save some of the Agena's fuel to power a high ride.
He began a small crusade to convince NASA management that there were good reasons for going really high. Although the Weather Bureau had satellites flying at very high altitudes, their televised pictures of cloud formations had poor resolution.  Moreover, the Bureau had been debating the use of a color system. Conrad argued that Gemini XI could bring back films to help them decide its worth. It was, in fact, to the experimenters that he first turned in his campaign to fly high, asking which experiments might be helped and which degraded by higher altitudes. He learned that Maurice M. Shapiro of the Naval Research Laboratory was concerned that radiation particles from the Van Allen belts might affect his nuclear emulsion experiment at the higher orbit. That almost killed Conrad's plan before it was well started. But he enlisted fellow astronaut Anders, a nuclear engineer, for a trip to Washington to argue against the threat. After Anders got friends at Goddard Space Flight Center to look into the radiation belt hazards and to devise ways of avoiding them, the high apogee excursion soon became part of Gemini XI.6
Another unique objective for XI, direct (first orbit) rendezvous, had been suggested before Gemini flights began. Proposed by Richard R. Carley of GPO, the idea had been put aside when interest had focused on a concentric, fourth-orbit plan. Carley's proposal revived when the Apollo office insisted on a closer simulation of lunar orbit rendezvous. With some signs of reluctance, GPO asked McDonnell to study the maneuver. The first meeting to phrase plans and ground rules for the study revealed some foot-dragging; its results included a curious stipulation: "There should be no artificial restrictions in the plan to make the mission simulate Apollo operations or to simulate lunar rendezvous conditions."7 That position was soon reversed as Apollo interests prevailed. The first change in the flight plan to include direct rendezvous made any launch delay a reason or shifting the mission to "a modified M = 3 [rendezvous in the third orbit] plan," but the following version "recycled [the launch] to the next direct rendezvous launch opportunity."8
Although schemes for achieving artificial gravity in space preceded real manned space flight by many decades, Gemini offered the first chance to turn science fiction into fact. Half the program had passed, however, before NASA got around to planning tethered vehicle flights. GPO first asked the Engineering and Development Directorate to study the problems involved in tying the Gemini spacecraft to either the Agena or the Pegasus satellite.9 Its backlog of Apollo work forced the directorate to decline its aid, in view of the extensive simulation required. Appeals to Flight Operations were more fruitful, however, leading to a number of tether simulations, the data from which were duly passed along to McDonnell.10
McDonnell's guidance and control group found that nylon or dacron tethers no longer than 50 meters and a spin rate no more than ten degrees per second produced a reasonable amount of cable tension and recommended that the pilots practice spinning on a vehicle simulator to learn how best to conserve fuel.11
 When NASA planners listed tethered flight as a mission objective, they first thought of it as a way of evaluating the tether as an aid to stationkeeping;12 but it might also be a means of inducing some degree of artificial gravity. The minimum spin rate depended on whether the tethered activity was intended primarily for formation flying or for achieving gravity. NASA decided to try for both, although it would settle for "an economical and feasible method of long-term, unattended station keeping," and chose a 36-meter dacron line.13
The Gemini Mission Review Board reviewed all these new activities in depth, especially the first-orbit rendezvous, which might be a heavy fuel user.14 Young and Collins had expended so much fuel in the Gemini X rendezvous that the board was dubious about trying a first-orbit linkup, largely computed onboard, with an Agena target. But Flight Director Glynn Lunney assured the group that Mission Control could give the crew backup data on orbital insertion and on the accuracy of their first maneuver; the network would have plenty of information to help them begin the terminal phase of rendezvous. The board concluded that if the rendezvous used only half the fuel supply, about 187 kilograms, there would be ample for the rest of the mission. Some skeptics remained; William Schneider, Deputy Director for Mission Operations, bet board chairman James Elms a dollar that it could not be done that economically.15
The board seemed less concerned about the high apogee maneuver and the tethered vehicle exercise than about direct rendezvous. Radiation levels on Gemini X having been only a tenth of the preflight estimate, the board simply asked that MSC and Goddard keep track of the latest measurements. The only major question about the tether plan was the method for freeing the spacecraft from the Agena. The board was told that the plan was to fire a pyrotechnic charge, ejecting the docking bar at right angles to the spacecraft path. If that did not work, there was a break link in the tether that could be snapped by a small separation velocity.16
As might be expected, extravehicular activity received special attention. After the experience on Gemini IX-A, training methods were sought that would more closely approximate flight conditions. One likely approach simulated zero-g by putting a space-suited subject under water, where buoyancy almost balanced weight, and leaving him to cope with mass and inertia just as he would have to do in space.17 Despite the degree of EVA success that Collins had in Gemini X, work on this idea went ahead. There were, as MSC Director Robert Gilruth later said, "many mixed emotions here at the Center - some of our people didn't think the neutral buoyancy work was any good." But Cernan, who checked out the method at Gilruth's request, found that moving about under water in a pressure suit closely matched his efforts in space. These findings, however, were not impressed upon Gordon in his training for Gemini XI.18
 More was needed than a better training medium. Both equipment and body positioning aids had to be improved. Hardware changes included handholds on the target vehicle docking cone, a shorter umbilical, and better foot restraints in the spacecraft adapter. The handholds were simple to design and install. Both Collins and Young had complained about the 15-meter snake that had entangled Collins. They suggested its length be cut to 9 meters, and GPO agreed. Developing better foot restraints took a little more time. McDonnell was working on two kinds - a spring clamp like those on a ski and a bucket type. NASA chose the latter, which were nicknamed "the golden slippers."19
Twelve experiments were included in the Gemini XI flight plan (see Appendix D). Nine were scientific; the other three technological. Two of the science experiments - S-29, Earth-Moon libration region photography, and S-30, dim light photography/orthicon were new to Gemini. The other seven - weather, terrain, and airglow horizon photography; radiation and zero-g effects; ion-wake measurement; nuclear emulsion; and the ultraviolet astronomical camera - and all three technological experiments - mass determination, night image intensification, and power tool evaluation - had been assigned to previous missions. The Gemini Mission Review Board concluded that they fitted properly into the Gemini XI workload. By 25 August, MSC was able to report that all experiments were ready for flight.20
When reduced launch intervals required faster delivery to the Cape, the challenge was met. Before the end of July, launch preparations were under way in Florida. On 11 August, NASA announced that the flight would be launched on or about 9 September, only two days after the target date set more than three months earlier.21
The countdown-to-launch began on schedule on 9 September 1966, but it did not finish that way. After the booster was fueled, the launch crew detected a pinhole leak in the first stage oxidizer tank, which had to be fixed. Technicians used a sodium silicate solution and an aluminum patch to plug the leak; and Mission Director Schneider reset the launch for 10 September.
Trouble for the second scheduled send-off cropped up in a different area and much later in the countdown. Conrad and Gordon had completed the required rituals and headed toward pad 19 and their spacecraft when they heard that the Atlas, only 1,800 meters away, was having a problem with its autopilot. The General Dynamics test conductor called a hold in the countdown to have this suddenly wayward instrument checked. His engineers told him they were receiving faulty readings and were running checks before deciding whether to replace the part. When the delay had stretched to an hour, Schneider postponed the launch for two more days. The problem was caused by a combination of factors - a fluttering valve, unusually high winds, and a too-sensitive telemetry recorder - none of which required replacement of the autopilot. There would be no further delay.22
5 Char1es Conrad, Jr., interview, Houston. 31 March 1967; "Preliminary Project Development Plan for an Advanced Manned Space Program, Utilizing the Mark II Two Man Spacecraft," STG, 14 Aug. 1961, App. A; "Gemini Large Earth Orbit," McDonnell Control No. C-100858, Report B743, 19 June 1965; Meyer, interview, Houston, 9 Jan. 1967; Meyer, notes on GPO staff meetings, 29 June, p. 1, and 27 July 1965, p. 1; letter, Rep. Olin E. Teague (D.-Tex.) to James E. Webb, 18 Aug. 1965; letter, Webb to Teague, 10 Sept. 1965; letter, George E. Mueller to Abe Silverstein, 1 Sept.1965; memo, Edgar L. Harkleroad to Chief, Gemini Mission Planning, "Gemini-Pegasus Rendezvous Summary to date," 25 May 1965; Meyer notes, 25 Jan. 1966, p. l.
6 Conrad interview; "Summary Minutes, Seventh Inflight Experimenters Meeting, 67-1," held 25-26 Aug. 1966, p. 5; "Trajectories and Orbits Meetings, June 29 and July 8, 1966"; "Gemini Program/Mission Directive," NASA Program Gemini working paper No. 5039, 19 Nov. 1965, Appendix A, "Gemini Missions," Change 4, 12 July 1966, pp. A-11-1 through -5; letter, Mueller to Gilruth, 1 Aug. 1966, with enclosure; memo, John M. Eggleston to dist., "Information on Radiation Hazard to Gemini and Apollo from the Solar Flare Particle Event of September 2, 1966," 9 Sept. 1966.
7 Memo, Christopher C. Kraft, Jr., to dist., "Second meeting of Mission Planning Coordination Group," 22 Oct. 1963; Raymond L. Zavasky, recorder, "Minutes of Senior Staff Meeting, June 12, 1964," p. 3; TWX, Mathews to SSD, Attn: Col. Richard C. Dineen, "Direct Ascent Rendezvous Guidance for Gemini," GP-51690, 12 Feb. 1965; memo, Mathews to dist., "Mission Planning for Gemini IX, X, XI, XII," GV-66289, 2 Dec.1965; Mathews memo, GV-66300, 27 Dec.1965; TWX, Mathews to McDonnell, Attn: Burke, "Contract NAS 9-170, Gemini, Development of Gemini Computer Math Flows," GS-10090, 5 Jan. 1966; TWX, Mathews to McDonnell, Attn: Burke, "Contract NAS 9-170, Gemini, Initial Conditioning for First Apogee Rendezvous Analyses," GS-10095, 2 Feb. 1966; TWX, Mathews to SSD, Attn: Dineen, "Mission Planning Information," GV12386, 16 March 1966; "Abstract of Meeting on Trajectories and Orbits, April 19, 1966," 6 May 1966; Wyendell B. Evans, telephone interview, 20 Aug. 1973.
8 Mathews memos, GV-66289, 2 Dec. 1965, and GV-66300, 27 Dec. 1965; Meyer notes, 25 Jan. 1966, p. 1; "Gemini Program/Mission Directive," p, A-1 1-1, Change 1, 1 Jan. 1966, and Change 2, 15 Feb. 1966.
9 Eugene M. Emme, A History of Space Flight (New York, 1965), p. 86; Willy Ley, "Station in Space," in a symposium entitled "Man Will Conquer Space Soon," Colliers, 22 March 1952, p. 30; Wernher von Braun, "Crossing the Last Frontier," ibid., pp. 29, 72; memo, Mathews to Asst. Dir., E and D, Attn: William E. Stoney, "Tethered vehicle studies," GV-66209, 1 Oct. 1965.
10 "Tethered Vehicle Study," [GPO], 26 Oct. 1965; memo, Robert C. Duncan to Mgr., GPO, through Asst. Dir., E and D, "Tethered vehicle studies," EG-65-921, 26 Oct. 1965; memo, Eldon W. Hall to Actg. Dep. Dir., Gemini Program, "Tether Studies," 4 Nov. 1965; David D. Lang, telephone interview, 22 June 1970; memo, Lang to Grimwood, "Comment Draft Chapter . . . of Gemini Narrative History," 22 June 1970.
11 Phillip McLaughlin, "Spin Up Studies for the Gemini-Agena System in a Tethered Configuration," McDonnell Gemini Design Note No. 356, 23 March 1966.
12 "Gemini Program/Mission Directive," p. A-11-2, Changes 2 and 4.
13 McLaughlin, "Spin Up Studies," p. 4; "Gemini Program Mission Report, Gemini XI," MSC-G-R-66-8, October 1966, pp. 1-3, 5-86; NASA Release No. 66-226, "Project: Gemini 11," press kit, 24 Aug. 1966, p. 11.
14 James C. Elms, telephone interview, 29 Oct. 1969.
15 Elms, "Second Interim Report - Gemini Mission Review Board, August 18, 1966;" Elms interview.
16 Elms, "Second Interim Report"; TWX, Mathews to McDonnell, Attn; Burke, "Contract NAS 9-170, Gemini Configuration Control Board Meeting Number 96, March 28, 1966," GV-12389, 31 March 1966; TWX, Mathews to McDonnell, Attn: Burke, "Contract NAS 9-170, Gemini/Agena Tether Break Link," GV-12482, 28 July 1966.
17 "Abstract of Meeting on Extravehicular Activity on Spacecraft 10, 11, and 12, June 30, 1966," 6 July 1966; letter, Mathews to Langley Research Center, Attn: Dir., "Simulation support for Gemini extravehicular activities," GV-66466, 30 June 1966, with enclosure, "Statement of Work"; letter, G. Samuel Mattingly to MSC Historical Office, 5 Oct. 1970.
18 Memo, Donald K. Slayton to Mgr., GPO, "Gemini Extravehicular Operation," CF40-4M-51, 23 March 1964, with enclosure, Appendices, esp. Appendix B, "Astronaut Training Program," p. 6; "Abstract of Meeting on Extravehicular Activity on Spacecraft 11 and 12, August 2, 1966," 4 Aug. 1966; Gilruth, interview, Houston, 21 March 1968; Reginald M. Machell, interview, Houston, 18 April 1967; Richard F. Gordon, Jr., interview, Houston, 20 March 1967.
19 "Extravehicular Activity Meeting, June 30, 1966"; memo, Mathews to Mgrs., EXPO and Spacecraft, "Action items resulting from the Design Certification Review of July 11, 1966," GP-62286, 18 July 1966; TWX, Mathews to McDonnell, Attn: Burke, "Contract NAS 9-170, Gemini, Delivery of 30-Foot Umbilicals," GP-7620, 28 July 1966; "Meeting on Extravehicular Activity, August 2, 1966;" "Abstract of Meeting on Extravehicular Activity on Spacecraft 11 and 12, August 16, 1966," 22 Aug. 1966; TWX, Mathews to McDonnell, Attn: Burke, "Contract NAS 9-170, Gemini Configuration Control Board Meeting Number 117, August 15, 1966," GV-12497, 17 Aug. 1966; TWX, Mathews to McDonnell, Attn: Burke, "Contract NAS 9-170, Gemini, Thermal Performance Testing on 30-Foot Umbilicals," GS-10126, 19 Aug. 1966; letter, Mathews to NASA Hq., Attn: Mueller, "Open item, Design Certification Review Board, Gemini XI; extravehicular feet restraints," GA-60465, 27 Aug. 1966; memo, Clarence C. Gay, Jr., to dist., "July 11, 1966 Design Certification Review Action Item," 7 Sept. 1966; Frederick T. Burns et al., "Gemini Extravehicular Activities," in Reginald M. Machell, ed., Summary of Gemini Extravehicular Activity, NASA SP-149 (Langley, Va., 1967), p. 3-19; Larry E. Bell et al., "Life Support Systems for Extravehicular Activity," ibid., pp. 4-88, -89; David C. Schultz and Hilary A. Ray, Jr., "Body Positioning and Restraints," ibid., pp. 5-2,-3.
20 Memo, Mathews to NASA Hq., Attn: Schneider, "Gemini XI Mission Priorities," GV-66488, 2 Aug. 1966; memo, Mueller to Adm., "Gemini Mission XI," 6 Sept. 1966, with enclosure, "Mission Operations Report, Gemini XI Mission," M-913-66-13, pp. 2-11; Gemini 11 press kit, p.16; "Seventh Inflight Experimenters Meeting," p. 7; "Interim Report, Manned Space Flight Experiments, Gemini XI Mission, September 12-15, 1966," MSC-TA-R-67-2, May 1967; Elms, "Second Interim Report."
21 TWX, Mathews to SSD, Attn; Col. John B. Hudson, GP-7536, 29 April 1966; letter, Mathews to Albert, GP-62168, 3 May 1966; TWX, Mathews to SSD, Attn: Capt. Davis B. Conkling, "Major Hardware Shipment for Gemini XI Mission," GA-6022, 20 June 1966; NASA News Release No. 66-215, "Gemini Eleven to Fly Sep. 9 on 3-Day Plan," 11 Aug. 1966.
22 [Ivan D. Ertel], Gemini XI Mission: High Altitude, Tethered Flight, MSC Fact Sheet No. 291-H (Houston, October 1966); "Gemini XI Mission Report," pp. 5-106, -107; Alexander C. Kuras and John G. Albert, "Gemini-Titan Technical Summary," 24 Jan. 1967, p. 149; Gemini 11 News Center Release No. 9, "Status Report," 9 Sept. 1966; Gemini 11 mission commentary transcript, 9 Sept. 1966, tape 1, p. 1, 10 Sept. 1966, tape 3, p. 1, tape 5, p. 1, tape 7, p. 1, tape 17, p. 1, tape 18, p. 1, tape 28, p. 1; "Gemini 11 Scrub Press Conference," 10 Sept. 1966; Gatha F. Cottee, telephone interview, 23 Aug. 1973; "Gemini XI Mission Report," p. 6-2; Gemini 11 News Center Release No. 13, "Status Report," 11 Sept. 1966.