“Godspeed, John Glenn.” Fifty years ago this past Monday, and with just seconds remaining in the launch countdown, Scott Carpenter uttered those words, one of the original Mercury Seven astronauts to another. When the countdown clock reached zero, John H. Glenn began a spaceflight that would ultimately see him orbit the earth three times. From the public’s point of view, American participation in the space race had begun in earnest less than ten months previously when Alan Shepard took his 15-minute ride into space. Although it had taken nearly a full year, with Glenn’s Friendship 7 mission, America had finally equaled the Russia’s April 1961 launch of Yuri Gagarin into Earth orbit.
The lead-up to Glenn’s orbital mission had seen a variety of postponements, including a five-week delay in mid-December 1961 and three separate mission scrub on January 27th and 30th and February 14th. Glenn was the first American to ride to space on the Atlas launch vehicle, a repurposed intercontinental ballistic missile, itself no stranger to drama. On May 18, 1959, the Mercury Seven astronauts, who’d only been introduced to the public five weeks earlier on April 9th, were at Cape Canaveral to witness an Atlas launch, the only American rocket at that time that was powerful enough to place a Mercury capsule into orbit. Shortly after launching, the Atlas veered sideways, its paper-thin metal skin rippling and crumpling. The potent mix of kerosene and liquid oxygen that powered the missile exploded in an enormous fireball. Ever the cool test pilot, Alan Shepard leaned into John Glenn and said, “I sure hope they fix that.” Even after the combination of the Mercury space capsule and the Atlas missile began the official series of tests leading up to Glenn’s flight, two more Mercury-Atlas launches, both unmanned, ended when the Atlas missile exploded. In contrast with the risk-free space flight that the public has come to demand of NASA in more recent decades, the early days of Cape Canaveral-to-Earth-orbit were a more hazardous proposition.
Glenn’s February 1962 flight faced its share of difficulties. Towards the end of his first orbit, Glenn reported back to Earth that his spacecraft was surrounded by glowing, whirling flecks of light that he called “fireflies.” This moment was recreated in the film The Right Stuff, where it was mystically suggested that ceremonial fires started by Indigenous Australians—Glenn first reported the phenomenon while over Australia—had been blown up into the heavens and were encircling Friendship 7. NASA scientists and engineers ultimately explained the fireflies as bits of ice working their way out of the spacecraft’s systems. Perhaps less imaginative an explanation, but judging Glenn’s own words, no less beautiful.
Glenn faced much greater danger during the middle of his flight when telemetry reported a “Segment 51” warning, an indication that Glenn’s landing bag, an inflatable ring used to cushion the spacecraft’s water landing, may have deployed. Flying accidents generally result from the accrual of many smaller errors. In this case, a possibly deployed landing bag also indicated a possibly damaged heat shield. Without a functional heat shield, an engineered barrier against the 3000-degree heat of reentering the earth’s atmosphere, the Friendship 7 capsule would be consumed in fire and Glenn would perish inside.
As Glenn made his third and final orbit of the earth, mission controllers, scientists, engineers, and administrators struggled to come up with an appropriate plan for this dangerous scenario. The decision was made to leave the spacecraft’s retro rocket pack—a group of three tiny solid fuel rocket engines that slow the capsule enough for Earth’s gravity to bring the spacecraft down to the earth’s surface—in place during the reentry phase. The retro-rocket pack was held in place, attached to the heat shield, by a series of metals straps. The hope was that, if the heat shield was damaged, the retro-rocket pack would hold the heat shield in place long enough for the shield to do its job. Glenn was told about the situation on his final orbit. He accepted it with a test pilot’s aplomb. In the end, the heat shield worked as designed, and Glenn returned to earth four hours, fifty-five minutes, and twenty-two seconds after he’d started his mission.
The rest of John Glenn’s life is befitting of someone who returned to earth an American hero: a career as a Senator and a return to space at age 77 onboard space shuttle Discovery. And that makes us think about this coming Friday, the first anniversary of space shuttle Discovery’s last launch, a launch we are sad to not have seen in person, though we had seen the orbiter on the launch pad, almost ready to go, the previous November. You can read our account of Discovery’s last mission in our “Countdown to the Cape” series.
The first three Americans into space were Alan Shepard on May 5, 1961, Gus Grissom on July 21, 1961, and John Glenn, fifty years ago this past Monday on February 20, 1962. The fact that we are celebrating the 50th anniversary of Glenn’s flight is a reminder that over the next several years, we will be regularly celebrating the 50th anniversaries of events that occurred during America’s golden age of space exploration. Next up will be the golden anniversary of Scott Carpenter’s Aurora 7 mission on May 24, 1962. Today, John Glenn and Scott Carpenter are the only living Project Mercury astronauts.
February 20 is also the anniversary of spacecraft Ranger 8’s crash into the Moon, a happy crash landing. On that date in 1965, it had already achieved its mission, namely to shoot photographs of possible landing sites for the Apollo program.
Lest we concentrate too much on the most modern forms of transportation, yesterday marked the seventh anniversary of Steve Fossett’s flight across the Pacific Ocean in a balloon. He was the first person to have done such a thing. Seven years later, he made the first airborne nonstop round-the-world trip, unless, of course, you count folks like Yuri Gagarin and John Glenn. Fossett disappeared in October 2007, and more than a year later, bones matching his DNA were discovered near his plane’s crash site.