A huge range of issues had to be resolved for Project Mercury. 3

from book

Thanks to Wernher von Braun – an ex-Nazi rocket scientist brought to the US at the end of WWII – the US already had a rocket booster called the Mercury-Redstone. This was powerful enough to send a human into suborbital flight – which meant reaching outer space, but not completing a full orbit around Earth. But the Soviets, at this point, had an even more powerful rocket, the Sputnik-PS. This allowed a spacecraft sitting atop the rocket to achieve full orbit around Earth. And on November 3, 1957, the USSR achieved another space first: a stray dog named Laika became the first living animal sent into orbit. Like the Soviet approach, the first Project Mercury missions were test flights carrying animal crews. At the time, the effects of zero gravity on the human body were unknown. Some doctors suspected gravity was required for certain body functions; others worried about the dangers of space radiation no longer blocked by Earth’s atmosphere.  But back to the timeline. NASA had a rocket capable of suborbital flight. But the flight plan – detailed information on the launch, reentry and recovery – needed to be developed.  This job fell to a NASA flight-research engineer named Christopher Columbus Kraft Jr. and his flight-operations division. This division would completely control the spacecraft, monitor its progress and check the biomedical readings of its crew. At the time, NASA’s ground support consisted of a basic concrete blockhouse near the launchpad. Kraft realized this was insufficient for the complex Project Mercury missions, and the idea of a mission control center began to take shape. The role of flight director, who commanded the mission control and made all final decisions, was also created, with Kraft taking on the role.   But although NASA might’ve had the booster rocket, they still needed to design a capsule to sit atop it. So von Braun and his team worked with aerospace engineer Max Faget to design it. The biggest question was reentry: How could they design a capsule capable of withstanding the extreme heat – around 3,500 degrees Fahrenheit – and pressure experienced upon reentry into Earth’s atmosphere? The first suggestion was a pointed, aerodynamic shape. But Faget’s colleagues soon pointed out that meteors with flat, rounded noses often survived the furnace-like heat of the fall. Eventually, they opted for a blunt-nosed shape that both slowed the capsule down and created a shock wave around the craft, deflecting a significant amount of heat.  Now they needed to test it.