Never Tell Me The Odds: 1-in-9 on STS-1

SpaceX's first-ever crewed mission was a success!
Now let's wind back the clock to 1981 and look at the last time a new American spacecraft took flight
_______________________________________________________________

In case you were wondering where today's article title comes from

As a SpaceX employee, both my job and my hobby writing Astronomical Returns always keep me up to date with the latest in space exploration. But since most people don't follow what's going on in space, I'm often left wondering what stories are actually big enough to make it into mainstream news, rather than the esoteric space babble I like to read. Fortunately, SpaceX's first crewed mission was certainly newsworthy - I was so thrilled getting texts from friends and family asking why this mission is so important! To put the historic launch into context, I told them that Dragon is the first new American manned spacecraft in 39 years, when the Space Shuttle first launched in 1981. It really shows how badly human spaceflight has stagnated

I waited 9 long years for this, but never in my wildest dreams did I imagine I'd get to witness it as a SpaceX employee

To be frank, I've never been a big fan of the Space Shuttle, though I do like the iconic orange external fuel tank and graceful orbiters. While it launched notable payloads like Hubble and helped build the International Space Station, most people agree it failed to deliver on its promise of cheap, reliable access to space and kept us confined to low Earth orbit for decades (not the mention the Challenger and Columbia disasters). But in getting myself psyched for SpaceX's first manned mission, I found myself researching the first Space Shuttle, and it turned out to be way more fascinating than I expected!

Liftoff of STS-1. Later Space Shuttles featured the classic rusty colored external fuel tank, but the first 2 were painted white

The Space Shuttle's origins date back to the late 1960s, as the Nixon Administration pondered what the post-Apollo space program would look like even before Apollo 11 touched down on the moon. NASA decided that a reusable spaceplane, reusable side boosters, and an expendable external fuel tank would be the best balance of capability and cost. By the late 1970s, NASA was performing atmospheric glide tests of the prototype orbiter Enterprise, named by popular demand after the famous Star Trek ship

Never intended for spaceflight, Enterprise was used on various Approach and Landing Tests to study the orbiter's aerodynamics

By 1981, Space Shuttle Columbia was ready to go. Curiously, NASA decided that the maiden voyage would carry a crew, even though the prior Mercury, Gemini, and Apollo spacecraft all had unmanned test flights before putting people on board (as did today's SpaceX's Dragon and Boeing's Starliner). There were a few factors behind this decision (source): 

  • More advanced computer modeling combined with multiple static fires and ground tests of the various components gave mission planners confidence the new spacecraft would work
  • Since it lacked the jet engines of a conventional airplane, having human pilots help maneuver the controlled glide would make descent much safer
  • Because STS-1 would land at Edwards AFB, NASA didn't want an untested spacecraft flying over California with no one in it. Prior spacecraft had all been designed for ocean recovery

STS-1 gliding through Earth's atmosphere during reentry

Great, so now that NASA has decided STS-1 would be crewed, who to select as the human guinea pigs? The choice of mission commander was a no-brainer: John Young. A veteran of four prior missions and one of the lucky 12 moonwalkers (having commanded Apollo 16), Young was the most experienced active astronaut in 1981. For copilot, NASA picked Robert Crippen, who certainly brought his own credentials as a naval test pilot despite being a rookie astronaut (not to mention a Texas Longhorn, just like me!). Years later when asked why NASA picked him for STS-1, Crippen simply responded, "Beats the hell out of me!"

Your Space Shuttle guinea pigs! Mission commander John Young (left) and pilot Robert Crippen (right)

Columbia lifted off from Cape Canaveral on April 12, 1981, coincidentally the 20th anniversary of the first human spaceflight by Yuri Gagarin on Vostok 1, and although the launch appeared smooth, the spacecraft was actually beset by numerous anomalies during its two day mission, ranging in severity from slightly cumbersome to borderline catastrophic. The most dangerous problems arose because the engineers underestimated the acoustic energy generated by launch: not only had high-intensity sound waves blasted off some of the thermal tiles that would protect Columbia during reentry, it had also warped the body flap near the back end of the shuttle need to control its descent!

Left: crew imagery clearly showing the missing tiles | Right: diagram showing the location of the body flap

NASA did its best to assess the missing thermal tiles, using ground-based telescopes and even a top-secret spy satellite to return imagery, and they ultimately concluded they could make it back safely (unfortunately, Columbia and her crew would not be so lucky 22 years later). For the damaged body flap, they basically got lucky; NASA engineers agreed the hydraulics should've been damaged, but somehow it operated normally during descent. Commander Young later said that had he known how bad the situation was, he and Crippen would have ejected during descent, meaning Columbia would be lost on its maiden voyage

Talk about guts! The saying goes, "I'd rather be lucky than good," but to succeed in spaceflight, sometimes you need both

Of course NASA addressed these issues on future Space Shuttle flights, and ultimately the mission successfully demonstrated proof of concept of America's new space plane. But subsequent risk assessments conducted by NASA estimated the probability of catastrophic failure on STS-1 being as high as 1 in 9! For comparison, the Commercial Crew Program that SpaceX's Dragon and Boeing's Starliner are currently part of requires a probability of loss no greater than 1 in 270, and that's for a mission lasting over 6 months. Hopefully with these more stringent requirements and modern technology, the spacecraft of the 21st century will be far safer than STS-1

For more about the trials and tribulations of STS-1, I recommend this article!






1 comment