Is It Safe?
People have been traveling into the stratosphere by balloon since 1931, when Auguste Piccard and Paul Kipfer rode in a pressurized gondola (Piccard’s invention) to 51,775 feet. A series of Navy and Air Force programs in the 1950s and 1960s used pressure vessels or pressure suits to get balloonists higher, some to above 100,000 feet. Skydiver Nicholas Piantanida set an unofficial record—123,500 feet— in 1966, but a later attempt went awry when his helmet depressurized. His team brought the gondola down, but Piantanida suffered brain damage from lack of oxygen. He died four months later.
High-altitude ballooning had claimed other lives over the years, and the elaborate life support systems created for both recent successes—felix Baumgartner’s well-publicized leap from 127,852 feet and Eustace’s later, higher one—make clear that ascents to the stratosphere require careful planning and protection. Aerospace engineers have pretty much mastered the “shirt sleeves” environment for airplanes and space capsules. Even in the worst-case life support scenario, the capsule can always detach and descend quickly back to breathable air, says Taber Maccallum, the chief technology officer at World View. “The consequences of a catastrophic failure in a balloon,” he says, “are simply that you fly home.” In a sudden decompression, he says, there is more than enough emergency oxygen on board. Zero2inifinty’s capsule will seal off affected sections.
The absence of oxygen and lack of pressure are the gravest threats, but not the only problems. At high altitude, the temperatures are frigid. In the vacuum of space a capsule encounters no air molecules, so it loses heat relatively slowly through radiation. But when a balloon rising to very high altitudes encounters increasingly colder air (as low as -112 degrees Fahrenheit), heat is transferred from the capsule’s surface to cooler air molecules just outside, and strong wind quickly replaces the now-heated air molecules with cold ones. Properly insulating the capsule is one of the trickier engineering challenges ahead, as is balancing passenger comfort against avoiding problems like windows fogging up.
Though it may seem counterintuitive, the least safe portion of a stratospheric balloon flight is right after launch, when the balloon is still close to the ground. If anything goes wrong, there isn’t much time for the pilot to open a parachute and steer the capsule to a safe landing. One way to mitigate the risk of trouble early in the flight is to take care that the ultra-
thin polyethylene balloon doesn’t tear, so World View will use a crane to stand the balloon up before inflating it, bypassing the traditional processes of unrolling the balloon as it inflates or laying it out on the tarmac, both of which are more likely to lead to a tear.
Both World View and Zero2infinity are planning a further safeguard against early balloon failure: Open the capsule’s parachute early, perhaps even before liftoff. With the parachute already deployed, a failure even at a few hundred feet would result in the same drifting landing as if the capsule were descending from on high. And the passengers won’t feel a jolt when the capsule detaches from the balloon. Still, both companies plan to pack several backup chutes (those, should they be needed, would come with the customary jolt).