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The Tricky Business of Splashdowns: How Many Sailors Does it Take to Recover an Astronaut?

Images of splashdowns have become iconic of the space race era; an Apollo command module suspended under its three red and white parachutes as it hits the Pacific Ocean have the power to invoke feelings of pride with an epic American venture.

Images of splashdowns have become iconic of the space race era; an Apollo command module suspended under its three red and white parachutes as it hits the Pacific Ocean have the power to invoke feelings of pride with an epic American technological venture. Splashdown signaled the end of a mission. Everyone could relax. The crew was home. But NASA originally didn't intend to use splashdowns as a landing method beyond the inaugural Mercury manned spaceflight program. Not only is landing in the open ocean dangerous for the astronauts, but splashdowns also require significant support from the US Navy. NASA chose splashdowns as the landing method for Mercury because of its simplicity from an engineering standpoint. The stages of reentry were simple. The Mercury capsule is blunt, its wide bottom covered by an ablative heat shield. As it fell from orbit, the capsule generated heat from friction with the increasingly thick atmosphere. This melted the heat shield, protecting the astronaut and the capsule. From that point, the capsule was left to fall freely. In the final stages of descent, parachutes deployed to slow its fall. It landed gently on the yielding surface of the ocean.

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Once in the water, the astronaut just had to exit the capsule and take a helicopter ride to the recovery carrier where jubilant crews and a clean pair of coveralls awaited him. But the simple splashdown and recovery of the astronaut was a little more complicated than it would seem.

There were many reasons why a Mercury mission might have to end early and return to Earth ahead of schedule. There was also the more likely possibility that some minor problem, like a false signal from the onboard computer necessitating a systems check, would delay reentry and change the splashdown point.

It helps to think about spaceflight like a ball being thrown in an arc; the ball's highest point is the capsule in orbit, and its fall is the capsule's descent. As the ball falls, or as the capsule returns from orbit, it loses forward momentum. No matter the ball's height or the angle at which it's thrown, the profile of its fall is the same – an arc. The same applies to a capsule. Its descent is always the same no matter where in orbit it begins its descent.

Any change to the reentry point was problematic because the Mercury capsule wasn't controllable in its descent stage – wherever the capsule was in orbit when it began its fall towards Earth dictated where it would land. Its descent path was unchanging. If the capsule began reentry later than planned, it would splashdown downrange from its planned impact point. The astronaut wouldn't land near his prime recovery carrier, or even within his landing zone.

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As a precaution in anticipation of an off-target splashdown, NASA designated multiple landing zones for each Mercury mission. The primary landing zone was where the mission was scheduled to land. Here, the prime recovery ships were waiting with the necessary support forces to assist in the recovery of the astronaut. There were also a number of secondary landing zones. These accounted for more minor changes in the landing profile like a late reentry. Finally, NASA set up a contingency zone; a landing area far from all others that gave the astronaut a proverbial oasis in the desert.

NASA never had its own Naval fleet; the organization relied heavily on the US Navy for assistance in splashdowns. The relationship was conditional: the Navy would support the nation's space program providing NASA operations didn't affect the day-to-day workings of the military. NASA made good on the arrangement while also making good use of the forces at its disposal by employing significant resources for each Mercury mission. More than one ship was needed in each of the recovery zones – the primary, secondary, and contingency zones. This translated to an array of ships covering the Pacific and Atlantic Oceans.

The recovery forces on hand to pluck John Glenn out of the ocean after his Friendship 7 flight makes a good case study for the amount of labor needed to manage a smooth splashdown.

For John Glenn's 20 February 1962 orbital flight, NASA employed 24 ships – 23 in the Atlantic and 1 in the Pacific. The 24 ships break down by type: 14 Destroyers, 2 Carriers, 1 Salvage ship, 2 ocean Minesweepers, 1 Frigate, 1 Anti-sub Destroyer, 1 Radar Picket Destroyer, and 1 Oiler.

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A more impressive way to look at these 24 ships is to take a rough estimate of crew size. Carriers, such as Glenn's prime recovery ship the USS Randolph, had a crew of 1615 men – 115 officers and 1500 enlisted men. Destroyers, in the case of Glenn's recovery included the USS Barry and the USS Blandy, had crews of 304 – 17 officers and 287 enlisted men. Salvage ships had much smaller crews; in this case the USS Recovery had a crew of 83, 6 officers and 77 enlisted men. Submarines such as the USS Norfolk brought 127 men into the mix with 12 officers and 115 enlisted men.

A conservative estimate puts the men on hand for Glenn's recovery at over 8,000. 8,000 men were on hand to assist one man, and this figure includes only the crews of the ships in the various recovery zones. There were also Marine helicopters to pull the astronaut and capsule out of the water and US Air Force planes circling to visually monitor the situation. Not to mention NASA had men and women at remote stations around the world as well as in mission control.

In the grand scheme of the Navy, 24 ships and 8,000 men is not extraordinary; at its peak at the end of the Second World War, the US Navy was operating close to 7,000 ships. But 8,000 men considered in the context of a single splashdown is much more striking, especially considering Glenn was a seasoned and decorated pilot who could likely have landed any aerodynamic body. Had the Mercury capsule had any aerodynamic properties at all, Glenn could probably have landed it on the National Mall right in front of the Washington Monument without compromising the wellbeing of a single spectator.

Glenn's flight was not outlandish in its use of Naval forces for recovery. Scott Carpenter's 24 May 1962 Aurora 7 flight had 22 ships on hand for recovery. Wally Schirra's 3 October 1962 Sigma 7 mission had the largest recovery force of any Mercury mission (or Gemini and Apollo mission for that matter) with 27 ships. Gordon Cooper's Faith 7, the last Mercury flight, matched Glenn's recovery forces with 24 ships. In all cases, the recovery forces were a mix of carriers, destroyers, oilers, and frigates spread across the Atlantic and Pacific Oceans.

The exceptions to the impressive array of ships on hand were Shepard's and Grissom's suborbital missions. Since neither astronaut went into orbit, there was almost no question of where the capsule would land. Both flights lasted less than 15 minutes each and employed 10 and 8 ships respectively.

The astronauts didn't like being passive participants during the terminal phases of their missions, nor did they like the vulnerability associated with landing in the open ocean. For NASA, relying on the Navy wasn't an ideal relationship. A pilot-controlled land landing would be easier to coordinate as well as cost effective. It was also the landing profile the astronauts fought for the moment they became astronauts. The resources necessary for an effective splashdown and recovery was just one of the factors driving NASA away form continued use of splashdowns. Another was sheer pride: falling out of the sky like that is just undignified.