A Matter of Yaw

- Part 2 -

Prepared by:
Steven Kovachevich © January 2015

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It was July 21, 1961, and Mercury Astronaut, Gus Grissom had just completed the successful flight of his Liberty Bell 7, Spacecraft. After splashdown almost immediately helicopters from the USS Randolph where hovering over head. According to procedure the helicopter was to hook the capsule and lift it partly out of the water so the astronaut could egress out the side hatch into a sling to be lifted into the helicopter for the short flight back to the carrier. Instead, as the helicopter moved-in to hook on to the spacecraft the hatch blew off. The spacecraft immediately took on water and sank after an attempt to save it was abandoned due to a mechanical issue in the helicopter. Grissom was recovered.

The reason and blame for premature activation of the hatch mechanism continue to be a matter of interpretation.1 However, events leading up to loss of the spacecraft are another example of how the learning curve impacted early manned spaceflight. Like spacecraft navigation in the case of Scott Carpenter and Aurora 7, development of recovery techniques were in their infancy a matter of first impression without a guide. Events were moving at an accelerated pace with the goal of placing a man in orbit to beat the Russians paramount. The participants were essentially making the thing up as they went. Timing of events, the nature and content of mission rules, recovery procedures and other particulars were built on the steps of past experience of which there was little. Manned spaceflight was new and the effort based on a series of practice runs or simulations put together as best they could. Another look at the development of recovery methods and procedures reveals the factors that contributed to the loss of Liberty Bell 7.

In April of 1959 the seven Project Mercury astronauts reported for duty and their training was undertaken immediately.2 Among the training subjects covered in this early period was "egress and survival training."3 Initially, the primary exit for egress from the Mercury Spacecraft was through the small end at the top.4 A hatch behind the control panel allowed for access to the parachute canister that could be pushed out to create a passage to the outside. Although, this method was difficult and cramped. Among changes to the spacecraft, some introduced by the astronauts, were the addition in May 1959 of a quick-release side exit hatch.5 In October 1959, funds were approved for major changes to the Mercury spacecraft that included the egress hatch installation and astronaut observation window.6

Recovery techniques and methods were heavily influenced by and dependent upon the military services involved in the process including navy, air force and marines. In February 1960, early in the development of recovery techniques, the Navy's School of Aviation Medicine modified a standard 20-man raft in such a way that it could be placed around the base of a floating spacecraft with impact skirt extended. When the device was inflated, the spacecraft rode high enough in the water to permit easy egress from the side hatch.7 In January 1960, a document entitled "Overall Plan for the Department of Defense Support for Project Mercury Operations was reviewed and approved by NASA HQ.8 Based on requirements listed in STG, Space Task Group in charge of Project Mercury, working paper no. 129 covering the Project Mercury recovery force, the Navy issued "Operation Plan COMDESFLOTFOUR No. 1-60". This plan provided for recovery procedures according to specified areas and for space recovery methods.9 Although, subsequent events indicate the Navy did not initially include use of the spacecraft flotation collar in their recovery plans.

Rather, three recovery techniques were originally investigated. These included astronaut egress through the neck of the spacecraft and use of the raft to await recovery force arrival.10 The second, where recovery forces were in the recovery area at the time of impact, one of the recovery egress techniques practiced by the astronauts had the helicopter hook onto the spacecraft and lift it partly out of the water so the lower frame of the door was above the water line. The astronaut then ejects the hatch and climbs out of the spacecraft. The personnel lifting line or "horse collar", as it was called, is then lowered to the astronaut and, theoretically, he climbs into this and is lifted onboard the helicopter. The last method of egress practiced was the underwater one, where the spacecraft encountered a leak after impact such that use of the side hatch was necessary. Once the hatch is off, the spacecraft rapidly fills with water and the astronaut cannot get out until it is completely filled with water. Astronauts found they could get out under these conditions in around 10 seconds.11

Mercury astronaut recovery.

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(NASA photograph from SP-4001)

In August 1960, astronaut side-hatch-egress training was completed with a report of no difficulties encountered.12 The astronauts received refresher training prior their individual missions. It was during the refresher phases that better procedures were developed. An example was the helicopter mode in which a line was hooked to the top of the spacecraft which was partially raised out of the water by the helicopter. Next the astronaut emerged from the side egress hatch and was raised by a second line to the helicopter.13 The benefit of this technique is that it was the most rapid way out of the spacecraft.14

The report that no difficulties were encountered in astronaut side-hatch-egress training was not entirely accurate. The first attempt at the helicopter mode was not too smooth and another indication of why training was needed.15 Also, it was during training that use of the helicopter to carry the spacecraft with astronaut inside was ruled out because a helicopter dropped a spacecraft en-route to the recovery area during one of the early recovery exercises.16 There were other early indications of issues around water egress. The time recounted in the book The Right Stuff where Deke Slayton, one of the Mercury Astronauts, fell off a raft while egress training at Pensacola. Deke had the whole pressure suit on including the helmet when he went into the water and was going under and couldn't do a thing about it.17 Fortunately Gus and Wally Schirra were in the water and came to Deke's rescue.18 The Deke event was prescient.

So, on May 5, 1961, Alan Shepard's Freedom 7 made the first US spaceflight, a suborbital lob about 302 miles downrange of the launch site.19 The flight designated MR-3 for Mercury-Redstone 3 went off without a hitch. Shepard was recovered using the helicopter mode as previously practiced with no major difficulties. The Spacecraft along with Shepard were flown to the USS Lake Champlain ending the successful mission. Thereafter on July 21, 1961, Gus Grissom made his MR-4 Flight in Liberty Bell 7.20 The flight was successful from launch to splashdown. The same helicopter mode of recovery used on Shepard's flight was planned for Grissom's with no change in the procedure. In the case of Liberty Bell 7 though the helicopter mode ended in loss of spacecraft and the pilot almost drown. Loss of the capsule and Grissom's near drowning discredited the helicopter mode and focused attention on alternate recovery procedures including the previously tested flotation collar.

After the MR-4 flight, in August of 1961 seaworthiness characteristics of the operational Mercury spacecraft were evaluated. Conditions during the test varied from ground swells of 5 to 15 feet, wave heights of 2 to 10 feet, and winds of 6 to 20 knots. The test lasted for 33 hours and was deemed successful.21 In September of 1961, STG announced that a 30-inch diameter balloon would be installed in the Mercury spacecraft to allow for ship recovery should the helicopter be forced to drop the spacecraft, as happened during the MR-4 recovery operation.22 Also in September 1961, evaluation of the inflatable flotation collar, attached by scuba divers to sustain spacecraft buoyancy during recovery operations, was completed.23 On January 3, 1962, exercises were held at the Lynnhaven Roads Anchorage near Norfolk, Virginia, to determine the feasibility of using the auxiliary flotation collar in recovery operations. The tests were successful and the collar was adopted.24 Between January 15-17, 1962, Recovery area swimmers were trained at the Pensacola Naval Air Station, Florida, for use in John Glenn's Mercury-Atlas No. 6, MA-6, manned orbital mission. Instruction included films, briefings, auxiliary flotation collar deployment and jumps from a helicopter.25 The collar was also utilized in contingency planning for remote water landings initially accessible from search aircraft and para rescue personnel only.26

The final recovery technique settled on for the first orbital flight, MA-6, called for the astronaut to remain in the spacecraft until aboard ship and egress at that time.27 The recovery procedure included two swimmers deployed into the water from the recovery helicopter to affix a flotation collar to the spacecraft. The inflated collar provided a stable working platform at which time the astronaut could egress the spacecraft, or wait until onboard the recovery ship.28 While, three techniques were available including deployment of a flotation collar and retrieval of the astronaut only, simultaneous retrieval of astronaut and spacecraft with transfer of the astronaut to the helicopter, and simultaneous retrieval of the astronaut and the spacecraft with the astronaut remaining in the spacecraft, it was the last approach that was followed.29

The MA-6 recovery on February 20, 1962 was uneventful and followed the pre-planned procedure. After capsule splashdown the USS Noa, a destroyer, was only about six miles away. The Cape Capcom advised Glenn to remain in the capsule until recovery. Glenn radioed the recovery forces acknowledging his intent to stay with the capsule and his understanding recovery forces were going to put men in the water with the collar; although, they proved unnecessary. It took only a matter of minutes for the Noa to maneuver up to the capsule and hoist the spacecraft aboard all completed within 20 minutes of the landing.30 Glenn made egress out of the side hatch once the capsule was on deck. Thereafter, all the Mercury recovery operations employed scuba divers and floatation collars. In subsequent Mercury missions the astronauts stayed in their capsule until it was on the deck of the recovery ship rather than risk an egress at sea; Scott Carpenter being the only exception.

In the case of Grissom and Liberty Bell 7 the hatch incident is irrelevant to loss of the spacecraft which experience shows was avoidable with proper recovery procedures. The lack of para rescue scuba divers equipped with a floatation collar right from the very beginning seems odd as the possibility of an astronaut or capsule in the water was demonstrably present in early training exercises, supra. It is obvious the risk was not fully appreciated until it happened during a flight. The evolution of recovery techniques over the course of the early Mercury missions should not be a surprise as trials and errors were a part of the learning curve to develop a more thorough recovery procedure. A full appreciation of all the necessary elements had to be learned in a situation with limited experience and where simulations did not anticipate every possibility. Unfortunately, the inability to perceive, assess and reply to all the possible variables and consequences of a particular task is a repetitive theme in aerospace history. The ability to recognize problems and address them early in the learning curve was and continues to be a challenge in the pursuit of manned space flight.31 The experience of Scott Carpenter with yaw on MA-7 and Gus Grissom with the recovery procedure on MR-4 are only two examples.

1 Grissom maintained: ". . . The next task was to remove the cover and safety pin from the hatch detonator . . . I was lying flat on my back and. . . I heard the hatch blow-the noise was a dull thud-and looked up to see blue sky out the hatch and water start to spill over the doorsill. . . . I reacted instinctively. I lifted the helmet from my head and dropped it, reached for the right side of the instrument panel, and pulled myself through the hatch." NASA, Manned Spacecraft Center, Results of the Second US Manned Suborbital Space Flight, July 21, 1961, p.55 (hereinafter Second); On August 30th 1961, an investigation was conducted as a result of the premature activation of the MR-4 explosive egress hatch. Tests were initiated in an environment more severe than had been conducted in pre-launch activities and tests, but no premature firings occurred. Grimwood, James, M. Manned Spacecraft Center, Houston, Texas, Project Mercury A Chronology, 1963, p. 147 (hereinafter Chronology); Between August 4 and October 12, 1961, a series of environmental tests was conducted on the spacecraft explosive egress hatch because of the difficulties experienced during the MR-4 mission. Id.; "Oh, it was obvious. . . that Grissom had just . . . screwed the pooch. . . Oh, there was no question that he had hit the damn button some way." Wolfe, Tom, The Right Stuff, Farrar, Straus and Giroux, NY, 1979, pp.231-232; "I didn't know until I got the suit off that the hatch's firing ring had kicked back and barked my knuckles, my only injury from the trip." Glenn, John with Taylor, Nick, John Glenn A Memoir, Bantam, NY, 1999, p. 276; ; "A question had persisted on the blowing of his [Grissom's] hatch, and there were those who had maintained that Gus had inadvertently hit the plunger that exploded the bolts. . . [when I] blew the hatch on purpose. . . the recoil of the plunger injured my hand - it actually caused a cut through a glove that was reinforced by metal. Gus was one of those who flew out to the ship, and I showed him my hand. "How did you cut it," he asked. "I blew the hatch," I replied. Gus smiled, vindicated. It proved he hadn't blown the hatch with a hand, foot, knee or whatever, for he hadn't suffered even a minor bruise." Schirra, Wally, with Billings, Richard N., Schirra's Space, Naval Institute Press, MD, 1995, p.75; "I never believed that he panicked and blew the hatch. (Everybody who blew the hatch manually got a bruise, but Gus didn't.) I do believe, however, that it's very possible he bumped the switch by accident with the helmet." Other Voices - Walt Williams, Slayton, Donald K. "Deke" with Cassutt Michael, Deke! US Manned Space: from Mercury to the Shuttle, Tom Doherty Associates, NY, 1994, p.100; "Why did the hatch blow? We never found out. . . Wally Schirra spent hours in the capsule wriggling this way and that in an attempt to hit the detonator with his shoulder, his helmet, anything. He couldn't do it. . . That didn't stop the controversy. The press roasted him. . . I chose to believe [Gus]." Kraft, Chris, Flight My Life in Mission Control, Dutton, NY, 2001, pp.146-147; Author note: Grissom's spacesuit and helmet are on display at the Astronaut Hall of Fame in Florida. The helmet shows no evidence of damage from recoil of the hatch detonator.

2 Chronology, p.56

3 NASA, NIH, NAS, Proceedings of a Conference on Results of the First US Manned Suborbital Space Flight, June 6, 1961, p.53 (hereinafter First Suborbital)

4 First Suborbital, p.58

5 Chronology, p.60

6 Chronology, p.79

7 Chronology, p.94

8 Chronology, p.87

9 Chronology, p.87-88

10 First Suborbital, p.58

11 First Suborbital, pp.58-59

12 Chronology, p.109

13 Id.

14 First Suborbital, p.58

15 Id.

16 Id.

17 Wolfe, Tom, The Right Stuff,

18 Id.

19 Swenson, Loyd S., Jr., Grimwood, James M., Alexander, Charles, C., This New Ocean A History of Project Mercury, NASA SP-4201, 1966, p.341 (hereinafter TNO)

20 Id., at pp.369-370

21 Chronology, p.145

22 Id., at p.149

23 Id., at p.150

24 Id., at p.156

25 Id., at p.157

26 NASA, Manned Spacecraft Center, Results of the First United States Manned Orbital Space Flight, February 20, 1962, p.80 (hereinafter First Orbital)

27 Id., p.79

28 Id., p.80

29 Id., p.79

30 Id., p.81

31 "Kurt H. Debus, director of the Kennedy Space Center, was testifying before a subcommittee of the US House Committee on Science and Astronautics, investigating the cause of the fire (Apollo 1 fire that took the lives of Gus Grissom, Edward White and Roger Chaffee). . . "It was similar to an ice berg" Dr. Debus Said. "It took some early ships to run into an iceberg before we recognized that there was a lot of ice under the water. . . We never knew that the conflagration would go that fast through the spacecraft so that no rescue would essentially help. . . Had we known, we would have prepared. . . ." The twenty-twenty vision of hindsight was similarly expressed by Astronaut Deke Slayton. "I think we got lulled . . . into a sense of false security. . . We had no problems before and I think we all erred in not looking at it hard enough." Grissom, Betty and Still, Henry, Starfall, Thomas Y. Crowell Company, NY, 1974, p.192- 193.

Human Factors in Project Mercury: Reliability and Identification
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SEDR 109 Section I

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SEDR 109 Section II

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SEDR 109 Section III

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