The moment before the Gemini-B reentry vehicle is snagged by the JC-130B aircraft. (credit: J. Charles)
by John Charles
Late in the morning of a summer day in 1973, an Air Force JC-130B of the 6594th Test Group stationed at Hickam Air Force Base near Honolulu circled its assigned location about 250 nautical miles (460 kilometers) west-southwest of the big island of Hawaii. Its crew had just spotted their target: a satellite descending under parachute toward the Pacific Ocean. They were prepared to fulfill the group’s motto yet again: “to catch a falling star.”
In the 13 years since the first successful satellite air-catch, they and their predecessors had intercepted and retrieved over 300 recovery capsules carrying photographic film from Corona, Gambit, and Hexagon reconnaissance satellites, not to mention the data capsules from high-altitude Genetrix, Ashcan, Moby Dick, and Drag Net surveillance balloons before that, plus many hundreds more practice payloads. But this day’s retrieval was the most important and the riskiest yet: a capsule containing both high-value film and the astronauts who exposed it in orbit.
Their target was the Gemini-B reentry module from the most recent mission of the Manned Orbiting Laboratory, or MOL, a joint Air Force/National Reconnaissance Office program that had just concluded another 30-day mission of photographing the Soviet Union, China, Southeast Asia, and the Middle East.
The final stage of recovery started with a visual pass of the descending parachute just off the left wing tip so the pilot and the flight engineer could both visually check it from the top of the capsule harness up to and including the canopy. They looked for any indication of anything broken or missing that could hinder a good recovery.
The pilot announced on the intercom when the parachute passed the left wing tip, and the co-pilot started a stopwatch. The aft left loadmaster responded that he had it in view, then guided the pilot toward the desired rate of descent to match the descending parachute: “It’s below the horizon and rising—below the horizon and rising—coming up on the horizon,” and finally, “it’s on the horizon and steady.”
The copilot called out the time since the wing-tip passage, and at thirty seconds, the pilot announced he was beginning a standard rate turn to the left to fly back toward the capsule. During the turn, the aft left loadmaster made his final call: “On the horizon and out of sight.”
At the end of the turn, descending constantly to keep the bottom of the parachute aligned with the distant horizon, when the aircraft was finally lined up with the parachute, the pilot announced, “Inbound hot.” The winch operator responded that his final check was complete. Soon the pilot said “ten seconds warning” and then “under the nose.”
The Gemini-B’s parachute was modified with a smaller secondary cupola, called a cone, extending from the middle of the main parachute, making the whole thing look like a sombrero. The aircraft was dangling two 34-foot (10.4-meter) aluminum poles supporting a loop of 7/16-inch (1.11-centimeter) plastic-coated steel cable with four-pronged grappling hooks attached to it. The pilot tried to fly about 7 feet (2.1 meters) above the top of the cone to snag it about one third of the way up so the cable and hooks would catch on reinforced straps built into the parachute. If successful, the parachute would collapse and streamline, and the cable, parachute and capsule would be winched aboard.
After its main parachute was deployed, every Gemini capsule hung from a single suspension point while the pilots inspected the parachute through their forward-facing (now upward-facing) windows. When they were satisfied with its condition, they had transitioned to two-point suspension at a 55-degree nose-up angle to soften the impact by slicing into the water with the edge of the heat shield. Back on Gemini 3, the transition had been so abrupt that Gus Grissom cracked his helmet visor on a knob on the instrument panel, but subsequent crews didn’t report any problems. For this Gemini-B recovery, the capsule remained in single-point suspension with the pilots on their backs instead of sitting more upright. This had three advantages, all related to astronaut well-being.
First, in case of a near-miss by the aircraft, the astronauts could visually judge whether the hooks had damaged their parachute. If it was still intact, and if they were still high enough, another flyby attempt could be made. But if they were too low, then they would have to put the capsule into two-point suspension immediately and prepare for splashdown and a long wait at sea until one of the Air Force’s recovery ships arrived. Another aircraft would drop para-rescue swimmers called PJs with flotation gear to keep the capsule buoyant and stable.
If the hooks didn’t snag the reinforced straps but instead shredded the parachute, then the astronauts would have no choice but to eject from their free-falling capsule. Unlike Mercury, Gemini didn’t have a backup parachute: that function was provided by the pilots’ personal parachutes in their ejection seats. Ejecting perpendicular to the parachute from a capsule under single-point suspension was safer than ejecting upward into a parachute, even a shredded one, from a capsule under two-point suspension. Again, the PJs would join them to render aid until they could be rescued. The capsule—and its high-value film—would probably sink and be lost unless an undersea recovery effort could be mounted before the film deteriorated.
Second, if the snag was successful, then the brief 3g pulse of the capsule being accelerated to the aircraft’s 120-mph (193-km/h) horizontal speed was more tolerable, given the astronauts’ deconditioned state after a month in weightlessness, in the chest-to-back or “eyeballs-in” direction under single-point suspension than in head-to-foot or “eyeballs-down” direction under two-point suspension.
Third, it made the capsule marginally more stable as it was reeled in through the open cargo door at the aft end of the aircraft and onto its cradle. Dragging it through the aircraft’s turbulent slipstream narrow end first allowed its broad aft heat shield to stabilize it—slightly—like the feathers on a shuttlecock, and its barely-offset center of gravity kept the pilots more or less upright until their capsule was secured to the cradle, to be winched fully aboard the aircraft.
But even after a month in weightlessness, with memories of their space motion sickness early in flight receding but not gone, the inevitable gyrations and oscillations of being winched aboard provided another reason why the pilots were not unhappy that a flight surgeon and a medical corpsman were waiting for them aboard each recovery aircraft.
In fact, there were two prime recovery aircraft. Given the nature of the Gemini-B descent, there wouldn’t be time for the prime aircraft to circle back around in case of a miss. As a backup, another JC-130B trailed the prime recovery aircraft by about 30 seconds.
If both planes missed, then the Gemini-B would splash into the ocean, just like NASA’s Gemini capsules had done. It would be retrieved by one of the two surface recovery Victory Ships operated by the 6594th, the Longview and the Sunnyvale, each with a CH-3B helicopter. But the whole point of aerial recovery was efficiency and economy—not to mention depriving the Navy of any possible justification for its expensive and cumbersome assistance. Even the Air Force-operated surface ships looked too much like the Navy for blue-suiters who thought pilots should always land on runways. They were still unhappy that the inflatable Rogallo wing that had held such promise for landing NASA’s Gemini missions at Edwards Air Force Base proved too heavy to use even after the bugs had been worked out.
In addition to the two medics, there was also a technician from McDonnell Douglas, the company that built the capsule, who would safe the capsule’s systems, including the reentry control system’s maneuvering jets and its surrounding beryllium housing, as well as the ejection seats, batteries, and other potentially dangerous items. The astronauts had vented leftover fuel after they deployed the parachute, but the tanks were never really empty, and the two-hour flight back to Hickam would be a lot more pleasant if the crew didn’t have to worry about breathing toxic fumes.
There was also an armed courier aboard from an unnamed government agency who would remove the film canisters from the capsule and locked them in a large steel case that looked like a 55-gallon drum. After the episode back in 1960 when the 6594th wing commander had startled everyone aboard the C-119J aircraft by rummaging through the first recovered Corona payload during the return flight, this didn’t seem excessive.
Given the usual JC-130B crew of ten men (pilot, co-pilot, navigator, flight engineer, crew chief/winch operator, four loadmasters, and a photographer for satellite recovery missions), the four additional men and two astronauts made for a crowded aircraft.
After it was winched into the cargo compartment, the loadmasters secured the Gemini-B capsule as close to the aircraft’s center of gravity as possible. Heavy payloads made the aircraft harder to control; aircraft had been lost when such payloads had shifted or broken free.
The astronauts wanted to walk around to reacquaint their legs with gravity after the month in weightlessness, but, even though the cargo compartment was 40 feet (12.1 meters) long, 10 feet (3 meters) wide and had 4,500 cubic feet (127 cubic meters) of usable volume, the Gemini-B capsule and associated recovery gear took up most of the walking space. It was better for everyone if they just sacked out in the bunks at the rear of the cockpit. They could walk at Hickam, and then walk a lot more board the C-141 waiting to take them, their capsule, and their film on the long flight back to Moffett Field near Sunnyvale, California.
The scenario is fictional: MOL never flew and no crewed spacecraft was ever retrieved in mid-air. However, the possibility has fascinated me for 50 years (no kidding!) since I first read just two sentences near the end of a long article about MOL planning in the May 30, 1966, issue of Missiles & Rockets,1 a weekly aerospace trade journal that my high school library inexplicably carried:
“There is at least a possibility, admittedly remote, that the AF may suggest attempting to snatch the Gemini-B out of the sky during re-entry using the same methods developed for its Discoverer unmanned satellite series. Informed sources report that the airplane/skyhook recovery system developed for that program was man-rated and is available for use in the [MOL] program.”
That’s all it said. No other contemporary source ever repeated that suggestion, as far as I know. Still, the magazine probably didn’t just fabricate it. Trade journals then as now consulted a variety of informed sources while seeking out exciting aspects of familiar stories to make their coverage more interesting. Those sources may have offered that tidbit as speculation; certainly Missiles & Rockets reported it with appropriate skepticism. While I haven’t found any other mention of mid-air Gemini-B retrieval, research has yielded some even more surprising suggestions.
By way of background, remember that mid-air satellite recovery evolved from pre-Space Age reconnaissance balloon payload recovery, using the same general principles and equipment, and the same range in masses. Of the balloon-borne payloads, Ashcan weighed about 300 pounds (135 kilograms), and the Genetrix gondolas, about 1,400 pounds (635 kilograms.) Corona and Gambit satellite capsules weighed from 80 up to 250 pounds (35 to 115 kilograms), and Hexagon capsules, up to 1,100 pounds (500 kilograms.) Tests had also been conducted with dummy systems of up to 3,000 pounds (1,360 kilograms), but those had caused aircraft control problems after they were onboard. These facts plus the procedures of aerial recovery are all described in Corona Star Catchers,2 a compilation of oral histories published by the NRO in 2012. At 4,700 pounds (2,130 kilograms), the Gemini-B capsules and training boilerplates would have been among the heaviest objects the 6594th had recovered in mid-air.
The retrieval machinery aboard the aircraft found a variety of uses. In addition to ballistic capsules, the NRO investigated maneuverable vehicles called lifting bodies as film-carrying reentry vehicles.3 Of three such vehicles tested in the Prime program, only the third was recovered in mid-air, verifying that capability for the 411-pound (186-kilogram) vehicle. It would be interesting to know whether its aerodynamic shape made its recovery easier or more difficult.
Aircraft from the 6594th also retrieved data pods from downrange tracking ships by snagging their suspended lines with the same pole and hooks as they used to catch satellites. And sometimes they picked up personnel, too, in a spectacular and memorable ride.
The Gemini-B pilots would have been the first mammals retrieved by the 6594th, but not the first living things. The mouse and primate payloads developed as part of the Discoverer cover story for the Corona photographic satellites would have been recovered the same way, but only one mouse payload was launched, in 1959, and it blew up before reaching orbit. The primate payload was cancelled before it ever flew. A decade later, NASA’s three-shot Biosatellite program aimed to used Corona-type reentry capsules to return biological specimens for mid-air retrieval after up to 30 days in orbit. The first failed to re-enter; the third—crewed by a solitary pigtail macaque—disappeared into low clouds before the JC-130B could reach it and was recovered by helicopter after it splashed down. Only the second—carrying bacteria, frog eggs, pepper plants, wheat seedlings, vinegar gnats, amoebae, and other simple living specimens—was successfully caught as planned.
There were, however, other ideas that made even mid-air Gemini-B retrieval seem less audacious. Captain Robert Counts provided a surprisingly detailed account of plans to recover the Apollo three-man capsules in his edited oral history, chapter 3 in Corona Star Catchers. Then-First Lieutenant Counts was the navigator aboard the C-119J that first successfully captured a parachuting film capsule from Discoverer 14 in 1960. He recalled that, initially, there were three different recovery methods that were considered, and he described all of them on a single page.
The baseline was to have a large parachute lower the capsule into the sea; this was much like NASA actually opted to do, except using three smaller, 85.5-foot (26-meter) parachutes, any two of which were adequate for a survivable splashdown.4 A single parachute 121 feet (36.8 meters) in diameter would have the same area as two standard Apollo parachutes, and one 148 feet (45.1 meters) in diameter would match all three.
Counts said that he was involved in evaluating the two alternative approaches. Incredibly, the simpler of the two was to recover the Apollo capsule in mid-air, just as the Missiles & Rockets article posited for the Gemini-B. The Apollo would have a large main parachute and a small drogue parachute attached in tandem. He said that when they tested this concept at Edwards Air Force Base, the smaller parachute was the grappling target. Presumably they used a simulated Apollo capsule approximating the 12,000-pound (5,440-kilogram) weight of the real thing, over twice that of the Gemini-B capsule.
Amazingly, the third option was for the Apollo capsule to deploy an inflatable Rogallo wing, as had been planned for Gemini, and then for the astronauts to land it on the aircraft carrier! As difficult as it was to manually land a powered aircraft on a pitching and heaving carrier deck, and as much training as naval aviators required to become and stay proficient, it is almost inconceivable that this scenario, involving an unpowered glider piloted by deconditioned astronauts with limited visibility and no possibility to abort the landing attempt and go around for another try, was seriously considered. Nonetheless, Counts said that this, too, was tested at Edwards—the flying part, not the landing-on-an-aircraft-carrier part—where it was found to be extremely susceptible to turbulence from thermals or thunderstorms. This led to the abandonment of the whole flying capsule program “after a great deal of effort,” according to Counts, undoubtedly to the disappointment of those Air Force officials who seemed to believe that it was preferable to land anywhere but in the water.
Even the ambitious concepts described by Counts paled next to a proposal by Hiller Aircraft Co. in 1965 for a huge helicopter to catch a Saturn IB first stage in mid-air as it descended on a parachute.5
In comparison with those concepts, recovering Gemini-B spacecraft in mid-air no longer seems so farfetched. Practical or not, this scenario was not just a figment of an aerospace journalist’s imagination. Nonetheless, it was a questionable idea for several reasons.
First, the Gemini main parachute was normally deployed at just under 11,000 feet (3,350 meters) above the ocean and it descended at about 1,800-2,100 feet per minute (550–640 meters per minute), whereas the uncrewed capsules inflated their parachutes at 40,000 feet (12,100 meters) or more and descended at 1,200 feet (365 feet) per minute for retrieval at about 15,000 feet (4,600 meters) and below. The Gemini’s lower altitude and faster descent would give the searching aircraft much less time to locate the target and make its approach.
This situation could have been improved in three ways: a higher altitude opening, a slower descent, and more recovery aircraft. I posited the third option in the fictional scenario. If the Gemini parachute system was certified for opening at 18,000 feet, as was the Apollo system,4 then it might have permitted an earlier attempt or two by the JC-130Bs at altitudes of perhaps 14,000 feet (4,300 meters). A slower descent would have required a much larger parachute, as in the Apollo scenario described above would.
Next, bringing the capsule aboard the aircraft safely would have been problematical, and not just because of the increased likelihood of injuring the astronauts due to the rough handling of even a successful recovery, not to mention a botched one. The Air Force would justifiably cringe at the notion of “in-flight” loading of a large object carrying unburned fuels, toxic materials, pyrotechnics, and explosive charges. At this point in the flight of the Gemini-B, almost all of the on-board fuel and pyrotechnics would normally have been expended, except for any residual reentry control system fuel that was not fully vented, and of course the unused ejection seat rocket motors. Any problems in those areas might have led to aborting the mid-air recovery attempt.
However, the greatest problem with this recovery procedure would be managing weight and balance issues. It is not enough to simply load and secure the heavy payload: as that weight is moving forward through the aircraft, the pilot would have been managing the shifting center of gravity. Experience has shown that the most dangerous situation is where a payload shifted forward because it was not secured properly or was not properly located in the first place.
To say, as the article in Missiles & Rockets did, that such a risky and complex technique was “man-rated” might have been a stretch. Granted, they had successfully snatched personnel as well as payloads from fixed locations on the land or afloat. But there was a significant difference between retrieving a man and a manned spacecraft.
But questionable does not mean impossible. In the heady, can-do days of the early Space Age, such suggestions were common. The retrieval systems in the C-119Js and JC-130Bs were regularly modified and upgraded by the contractor, so technical solutions could have been designed and tested for such heavy payload retrievals. If we can accept that possibility, then it is easy to imagine what it might have been like aboard the aircraft after a successful mid-air recovery of a Gemini-B capsule…
Once out of their space suits, the two astronauts seemed happy to be back from space, despite their queasiness and unsteadiness. The crew chief came up to the cockpit and told the pilot that the MOL men were nice enough fellows and said to call them Dick and Bob, but he assumed those names were aliases.
”Yeah, Smith and Jones,” suggested the pilot.
“Maybe so,” said the crew chief, “and they also let out that they are both Navy officers.”
“Squids!” hissed the pilot. “Maybe they would have been just as happy floating out there for a while. Oh, well, maybe that’s a cover story, too. Who knows what the brass is thinking, anyway?”
Thanks to Dr. Charles Knapp, Dr. Dwayne Day and Mike Jenne for guidance and helpful comments.
- “Special Report: Military Space,” Missile & Rockets, May 30, 1966, p. 33.
- Mulcahy, Robert D., Jr., Corona Star Catchers: The Air Force Aerial Recovery Aircrews of the 6593d Test Squadron (Special), 1958-1972, Chantilly, Virginia: Center for the Study of National Reconnaissance, June 2012 (accessed May 24, 2018).
- Day, Dwayne, “Movements of fire and shadow,” The Space Review, March 5, 2018 (accessed June 17, 2018).
- Knacke, T.W. (Northrup Ventura Corp., Newbury Park, Ca.), The Apollo Parachute Landing System, TP-131, AIAA Second Aerodynamic Decelerator Systems Conference, El Centro, Ca., Sept. 1968 (accessed June 17, 2018).
- Day, Dwayne, “Monster chopper,” The Space Review, Jan. 28, 2008 (accessed June 22, 2018).