Skylab was launched 42 years ago. How should we consider its legacy?
Skylab launch on May 14, 1973.
This was sparked by Lenny Flank's very interesting diary about the "Skylab Strike". I kept returning to this intriguing statement:
The project was a disaster right from the start.
Was it really a disaster?
Several other programs and events should be reviewed before "disaster" is used to describe the Skylab program. Let's start with missions that can clearly be described as disasters:
Apollo 1 (AS-204)
Three astronauts were killed due to engineering errors and management incompetence. In isolation, various hazards were understood, but there wasn't an overall, aggregate view that put the different pieces together.
Challenger (STS-51-L)
Seven astronauts were killed due to engineering errors, management incompetence, and schedule pressures. Again, in isolation the hazards were understood, but there wasn't an advocate with the power to make the decision to hold back.
Columbia (STS-107)
Seven astronauts were killed due to engineering errors, management incompetence, and mechanical failure.
Now let's consider various Apollo missions.
Apollo 6
This second and final full-up unmanned launch of the Apollo systems encountered several problems. The most notable are:
- POGO acceleration from the first stage was much higher than previously measured. This is caused by longitudinal resonances along the rocket. This drives more fuel flow into the engines during the acceleration part of the cycle, temporarily increasing thrust. The engine control compensates, reducing the thrust to normal. Now the acceleration decays, reducing fuel flow. The engine control compensates, starting the cycle again.
- Failure of a hose in one of the second-stage engines. The operating conditions were different from the test conditions.
- When the second-stage engine failed and shut down, the computer attempted to shut it down completely, but instead it shut down a properly-working engine. This was due to control circuits being accidentally cross-wired. With only three of the five engines, it was marginal whether it could continue on course. As it happened, the computer was able to maintain control of the rocket.
As a test flight, Apollo 6 did precisely what it was supposed to do: expose faults and weaknesses in the device being tested. From this point of view, Apollo 6 was more successful that the "perfect" Apollo 4 mission, where everything seemed to work properly. The flaws found due to Apollo 6 were remediated for future missions.
Apollo 12
This mission had two well-publicized problems:
- Loss of electrical power and control in the Command Module just after launch due to two lightning strikes. While the Saturn V rocket control continued to operate, the Command Module was mostly non-functional. Approaching the deadline to decide whether to abandon the mission, the "Set SCE to AUX" command came up from Engineering at Mission Control. This reset the idled control circuits, bringing the Command Module back to operational condition.
- Once on the Moon, the video camera was accidentally pointed at the sun, burning out the tube. It was an embarrassing and unfortunate loss for the collection of video of the astronauts in action on the Moon.
The events Apollo 12 encountered were relatively mundane. We've all seen lightning strikes and the Sun. It highlights that otherwise robust equipment can be damaged by fairly innocent and common means. What other common causes of problems would need to be predicted, tested, and fixed in an extremely large and complicated system?
Apollo 13
This mission is considered a "successful failure" due to on-the-fly engineering to make up for equipment and control losses due to the explosion on the way to the Moon with the result of all astronauts returning safely. Several changes were made to subsequent modules either to avoid this type of problem again, or to add robustness to the system.
Skylab from Skylab 3 Command Module
Skylab launched May 14, 1973 and was subsequently visited by three missions. The technical severity of the problems with Skylab seem to fall between those of Apollo 6 and Apollo 12 on the low end, and of those with Apollo 13 on the high end.
Mechanical damage and failures were fixed by the Skylab 2 (Pete Conrad, Joseph Kerwin, Paul Weitz) and Skylab 3 (Alan Bean, Owen Garriott, Jack Lousma) missions, with the only inordinate danger being to Skylab itself, not the crew as in Apollo 13. While the repair work distracted from the science schedule, there was clearly value to the process of performing the repair in orbit. The extension to the Skylab 4 (Gerald Carr, Edward Gibson, William Pogue) mission made up for some of the earlier lost time, but also perhaps added to the various problems.
As for the ready acceptance that it was a "disaster", perhaps this comes from "guilt by association" with various events both before and after the mission. The notable issues of the damage during launch through the end of the Skylab project could very easily mix into the noise of other calamities at the time.
Some of the events in the few years before the Skylab launch:
- The assassinations of the President Kennedy, Dr. King, and Robert Kennedy
- The continuing, seemingly-endless war in Viet-Nam
- The continuing, seemingly-endless Cold War
- The various social upheavals of the 1960's
- The Watergate Scandal
As noted by Jim Lovell of Apollo 13, there was something of a "victim of success" situation with enthusiasm already waning by the time his mission was launched in 1970, less than a year after Apollo 11. It was supposed to be the third Moon landing.
Apollo 17 finished up the Moon missions in December, 1972. Having looked to the Moon high in the sky during the Apollo program, attention likely turned back to Earth, with all its everyday problems. How does one top going to the Moon?
Some of the events in the few years after the last Skylab mission:
- The energy crisis (started October, 1973, between Skylab 3 and Skylab 4)
- The resignation of Richard Nixon
- The hostage crisis in Iran
- The inability to prevent the re-entry and burn-up of Skylab in 1979
- The assassination of John Lennon
With the benefit of hindsight and a full awareness of the program, it's understandable that Skylab would easily take on the reputation of being yet another in a string of failures bound together by the ropes of malaise, failure, and incompetence.
Once 1981 rolled around, a number of events seem to make for a clean break from the doldrums of the 1970's:
- Ronald Reagan elected! Now we have a real hero for President!
- The hostages are released by Iran! That's finally over!
- The Space Shuttle is launched! It's reusable, not like that old Apollo junk!
- We can lower taxes to increase revenue! It's like free money!
Well, things aren't really that simple, but it was an easy narrative to push.
Mr. Bean goes to Space.
With this context, perhaps Skylab wasn't a disaster. A disaster would have been an explosion on the launch pad, a failure to reach orbit, or some other unrecoverable problem. While it suffered from incidents at launch that damaged the solar arrays, there was enough robustness and redundancy in the system to make it possible to affect repairs to restore near-complete functionality.
For being the first space station, made from "spare parts", it certainly did fairly well. The three missions generated a lot of scientific data and expertise useful for future space work. Like the Mercury and Gemini programs, Skylab wasn't the end result - it was an experiment and a research project all its own. As time goes on, perhaps one of the more enduring experiments will be the large collection of high-resolution photographs of the Earth as it was in 1973 and 1974. Data points that can't be re-created.
Skylab launched into orbit around a planet with a lot of worries. The echoes of past wars still rang; the sorrows of current wars were bitter. The economy was stressed, society was changing. The potential of the Skylab program clearly wasn't reached. How much more could have been done? Rather than dwell on mishaps, let's celebrate Skylab as a product of the time, complete with all its contradictions.
Close-up of a Pale Blue Dot from Skylab 2, June 22, 1973.