“In Silent Awe”: America’s Day-Long Record-Holders

Fifty-one years ago, this week, Alan Shepard made history as America’s first man in space. Atop a modified Redstone missile, he was hurled 188 km into the heavens, in a 15-minute suborbital ‘hop’ which began at Cape Canaveral and ended in the Atlantic Ocean, 160 km north of the Bahamas. In doing so, Shepard accrued numerous records for the United States: he became the highest-flying American in history, the fastest American in history and the first American in history to travel beyond the sensible atmosphere. Yet only hours before his pioneering voyage, on 4 May 1961, a pair of naval aviators undertook their own venture into the unknown. Their mission lasted almost ten hours and ended triumphantly and tragically; triumphantly in that the records they set remain unbroken to this day, but tragically in that one of them did not survive to enjoy the fruits of his success.

By the beginning of the Space Age, balloon-borne ascents into the high atmosphere had become more frequent, thought fraught with risk. For two decades, numerous nations – including the United States and the Soviet Union – had despatched explorers into the stratosphere and in the early 1950s the US Navy put its resources behind the creation of a manned balloon and pressurised gondola to reach the very edge of space. The project, known as ‘Stratolab’, saw its pilots rise in either fully-pressurised capsules or open gondolas, carried beneath enormous balloons, to altitudes as high as 26,100 m. New pressure suits were tested under the most extreme conditions, physiological measurements were taken, cryogenic life-support systems were evaluated and carbon dioxide ‘scrubbers’ were trialled. Moreover, ‘real’ scientific research was undertaken, including direct observations of the stratosphere and astronomical studies of Venus.

Stratolab was under the direction of Commander Malcolm Ross, a naval aviator and physics graduate, whose career actually started as a radio sports announcer and broadcaster. After joining the Navy, he trained extensively in meteorology and atmospheric science and flew in combat in the Second World War. After the conflict, he was released from military duty, but later rejoined the Navy and worked on the development of high-altitude balloons for meteorology and observations of cosmic radiation. It was Ross who initiated Project Stratolab and he and fellow naval officer Lee Lewis rose firstly to 23,100 m in November 1956 and 25,900 m in October 1957. By the spring of 1961, Ross had flown four Stratolab high-altitude missions. On the eve of the launch of America’s first astronaut, he would ride a balloon into the stratosphere for the last time.

Ross’ final flight was ‘Stratolab V’ and differed from the previous voyages, in that he and his co-pilot, Lieutenant Commander Vic Prather, rose not in a pressurised capsule, but in an open gondola. Their overriding objectives were to evaluate the Navy’s Mark IV pressure suit, which, in 1958, had been selected by NASA for its Mercury astronauts. Ross and Prather would subject the suit to the harshest environment it had ever encountered, ascending to a record altitude of more than 34,600 m and exposing it to temperatures as low as -94 degrees Celsius. The physiological focus of the mission made it unsurprising that Prather, a Navy medical officer was also aboard.

Prather’s heritage is particularly interesting. After earning his medical degree, he joined the Navy as a flight surgeon and devoted his career to aviation medicine. As a key participant in ‘Project RAM’, he had been involved in efforts to develop prototype space suits at the Naval Medical Research Institute in Bethesda, Maryland, and undertook studies into how well they would perform at extreme altitudes. On 4 May 1961, he would put his research to the ultimate test. At 7:08 am Central Standard Time, Prather and Ross rose from the flight deck of the USS Antietam, based in the Gulf of Mexico, aboard Stratolav V. Their gondola was suspended beneath a vast, 90 m polyethylene plastic balloon and parachute. Within an hour, they had travelled through 16,200 m and external temperatures had fallen precipitously. The splendour of seeing Earth from such high altitude was captivating. “In silent awe,” Malcolm Ross later recalled, “we contemplated the supernal loveliness of the atmosphere.”

In total, their flight lasted nine hours and 54 minutes and, at around 11:15 am, reached a peak altitude of 34,668 m – more than twenty-one miles – and established a record still unbroken by balloonists to this day. The ascent was not perfect, as they experienced condensation on their helmet visors and irritating communications difficulties. Finally, as Stratolab V descended, Ross became concerned that they were moving too rapidly, so he and Prather began dumping ballast out of the gondola. It did not help; they were still descending too rapidly. The men threw out every piece of additional weight that they could manage, including the radio, and at length the gondola achieved a stable descent rate. At 2,000 m, the men opened their helmet visors and were so relaxed and jubilant that they smoked cigarettes.  

At 4:02 pm, they returned to the waters of the Gulf and were quickly joined by one of the Antietam’s rescue helicopters. The ship itself was barely a few kilometres away. Malcolm Ross was winched aboard the chopper (after momentarily slipping back into the water), which returned, a few minutes later, for Vic Prather. As the medical officer was rescued and the helicopter jerked upwards, he found himself unable to keep hold of the line and plunged back into the water. Since his helmet visor was open, his suit flooded…far too quickly for even the rescue divers to get to him. By the time he was fished out of the Gulf, Prather was dead. It was devastating to Ross to lose his crewmate and, although he later served as a civilian consultant, he never undertook another voyage in a balloon.

Aside from Prather’s tragic end, the flight of Stratolab V was an enormous success, with every objective ticked off the list. The Navy’s Mark IV suits had performed with near-perfection under extreme conditions and their lasting legacy would be that they were used by the Project Mercury astronauts, and never once failed to deliver. President John Kennedy posthumously awarded Prather the Navy’s Distinguished Flying Cross for his heroism and extraordinary achievement and both he and Ross later received the coveted Harmon Trophy for Aeronauts. Although attempts have been made over the years to surpass their altitude record, it remains unbroken and is still officially recognised by the Fédération Aéronautique Internationale. For a period of just one day, Malcolm Ross and Vic Prather held the record for the highest altitude ever reached by an American citizen and, through their tests of the Mark IV pressure suit, enabled Project Mercury to establish a human presence in space.