Mission Control and Training

The astronauts assigned to the flight crews were not the only ones having to train for the mission. In February 1972, over a year before the launch of the Skylab station, the Mission Control Center team began running their first simulations for the missions.

The long-duration aspect of the Skylab program presented new chal­lenges for the mcc team that would require advance preparation. On the ground every moment that the crews were in space, a team of people would be supporting them around the clock in Mission Control. In fact the control team would be operating Skylab even when the astronauts were not aboard it. And for the Mission Control team as much as for the astronauts, Skylab was a new spacecraft, completely unlike anything flown before, with its own unique parameters and requirements. In addition, the work the crews would be doing on Skylab would be unlike anything done in space before, so new procedures would have to be learned in order to support them.

According to Phil Shaffer, the lead flight director, operations control for Skylab was a mixture of old and new for the flight directors, with some elements being very similar to those in Apollo, and others being different from anything flown before. “The part that is similar to prior programs is that there was a trajectory function and there were the systems functions,” Shaffer said. “There was an electrical guy, a communications guy, there was an environmental guy, you know, each with their support staff and in that sense was all very similar. The manning level or the expertise requirement was the same as if we were doing a lunar mission.

“The teams, if you stood away a little ways, looked like Apollo teams or Gemini teams in the way they were structured because there was a flight director who literally was responsible for everything, there was a capsule communicator for air-to-ground voice, there was a surgeon, and there was a networks guy,” Shaffer said. “And all of those positions, you know some of them had slightly different names. Like gnc [guidance, navigation, and con­trol] for the csm was called gns [guidance navigation system] for the Sky – lab to distinguish different positions. Different names were required when both the csm and Skylab were up and active at the same time. There was a limited on-orbit team for when the csm was powered down. There were five on-orbit teams that did planning, preparation, and support execution for the experiments, evas, maintenance and repair, or whatever else was going on. These teams were led by [Phil] Shaffer, Don Puddy, Neil Hutchinson, Chuck Lewis, and Milt Windler. There was also a trajectory team led by Shaffer that was decidedly different from the on-orbit teams. It supported launch and rendezvous, and deorbit and entry, and maintaining orbital life­time by raising the vehicle orbital altitude. They did all those calculations. So, there were six teams: five on-orbit teams and one trajectory team, basi­cally, for the year of the program.”

Differences began with the launch. The crews flew into space on one space­craft that was essentially a taxi carrying them to another spacecraft where they would spend the bulk of their mission. “Another thing that was dif­ferent was having two very dissimilar vehicles, with some of the time both being active, so that you had two com guys and two environmental guys and two electrical guys on occasion,” Shaffer said. “Certainly until you got the Skylab powered-down for leaving or the Command Service Module pow­ered-down for the habitation period. The situation on Apollo was similar during the lunar-landing sequence with the Lunar Module and csm being involved. It was a bit of a zoo keeping all of that business straight.”

The attitude control systems for the massive Skylab space station were also very different from both a conceptual and an operational standpoint than any of their predecessors. “The new for Skylab was not new in name but new in type and that was an attitude control system with Control Moment Gyros [cmgs] ,” he said. “That was a whole new business in place of small rock­ets, reaction control thrusters, to control the attitude. You had these giant cmgs that were wonderful. The cmg system was assisted by a cold gas sys­tem called TACS [Thruster Attitude Control System].”

Attitude control—which basically amounts to which way the spacecraft is pointing—on Apollo was pretty straightforward, a basic application of Newton’s law that states for every action there is an equal and opposite reac­tion. That law is what allows rockets to travel through space, even though there is nothing there to push against. A rocket engine burns fuel to gener­ate thrust, and the action of the engine spewing flame backwards leads to the opposite reaction of the rocket moving forward. The same principle that pushes a large rocket through space also, on a much smaller scale, allowed the Apollo spacecraft to control its attitude. Rocket engines burned fuel, and the spacecraft turned in the opposite direction. The Skylab Thruster Attitude Control System took that simple concept and applied it in an even simpler way. Rather than burning fuel, the TACS simply vented cold gas into space. The action of the gas being vented produced the opposite reaction needed to control attitude.

The cmgs worked on a more arcane principle of physics—angular momen­tum. Tilting the spinning rotor of a Control Moment Gyroscope resulted in a torque that would rotate the entire station. Attitude control via cmg had the additional benefit for a long-duration mission of requiring no fuel, rely­ing instead on the power produced by Skylab’s solar panels.

In addition to the new attitude-control techniques, Shaffer said, new Mis­sion Control responsibilities were added to provide support for the science operations on Skylab. “And then there were the experiments,” he said. “We had a control function for Earth sensing. We had a control function for the celestial viewing. One looked up, the other one looked down. We had a con­trol function—a control position—for all the biomedical activity, a control function for materials science.”

While Mission Control had been involved in science support before, nota­bly during the lunar research during Apollo, Shaffer said that the support needed to coordinate the Skylab research was substantially more complex. For example, both Skylab and Apollo missions included making surface observations from orbit. Skylab had its Earth resources observation pack­age and Apollo carried equipment in the Service Module’s sim [Scientific Instrument Module] Bay that imaged the lunar surface. Although there was a general similarity in function, they were very different in operation. “The

Earth resources guy [in Mission Control], for instance, had a huge coordi­nation activity he did with the aircraft overflight, and with the ground truth people, and with the weather service going on with his planning. This was dramatically different from the equivalent function on Apollo. The guy in the Command Service Module was not running the sim Bay.”

Another change for Skylab that was worked out before flight was the real­time mission planning that would have to take place while the crews were in orbit. On prior missions extremely detailed plans were laid out ahead of time. On Skylab more activities were scheduled on a day-to-day basis dur­ing the mission. Every day the flight control teams would plan out what the crew would do the next day. “The evening shift did the detail preparation for the next workday’s activities,” Shaffer said. “The midnight shift did the overall plan for two days hence. And in part I think that was done to provide shelf life for both the support data that was going to go to the crew for the upcoming day and to give negotiation and preparation time for the struc­ture of the plan two days hence.”

That’s not to say no planning was done further ahead. Rough outlines of activities were put together for a week in advance, structured around such things as astronomical or Earth resources observations that were to be made. Since those had to take place at a very precise particular time, they were placed on the schedule first, and other activities that were more flexi­ble were filled in around them.

“All of that was all done by the time we entered the upcoming twenty – four-hour thing; then the remaining pieces were put in,” he said. “The sur­geons would have to get their requirements in. Life sciences was a really big deal, so significant effort was needed to get all of their activities in within their constraints. Vehicle maintenance had to be done, including servicing the atm and the associated eva activity. All of that got dropped into the plan. All of that happened on the evening shift. And that was new. The nearest thing to it may have been the lunar excursion planning activity while crews were on the lunar surface for two or three days. It evolved, and we all got really comfortable with it.”

There was some concern about why there had to be so many levels of advanced planning, but the system proved effective. Among its strengths was that getting a good bit of the planning done early freed up more time to react to any unexpected situations or to finish any previous scheduling that needed adjustment. “If we needed more time to get the detail flight plan support stuff ready for the crew, you had it,” Shaffer said. “There was basi­cally another whole shift available to finish up that work. And if something was wrong with your big plan for the day, then you had time to renegotiate whatever problems that created.”

Of course, no matter how much planning was done in advance, there were always times the plan had to be changed as new circumstances arose. “The classic case, to me, happened on one of my watches,” said Shaffer, “and it comes up under my title of‘surgeon’s rigidity and the bologna sandwich.’ A volcano in Central America decided serendipitously to start a major erup­tion while we were on orbit with all of our wonderful erep equipment. Of course the geologists and geophysicists were going nuts because it was an opportunity to use much of the erep sensor equipment we had to really get new and significant information about an erupting volcano that they had never had the opportunity to get before. It would be like looking ‘down the gun barrel’ right through clouds. They really wanted to do this.

“The conflict was that the orbit track that was going to go over the vol­cano happened during an already scheduled meal. The surgeon, because of his dietary scheduling requirements rigor declared that they were critical, and he couldn’t change the mealtime. That might change the digestive pro­cesses results, and there was no compromise for it. And I had a lot of sym­pathy for both parties, but here was a one-time event and we were going to be up there for many, many meals.

“Finally after much debate, I resurrected mission rule one dash whatev­er it is that says the flight director is in charge in real time. It means he can do whatever he needs to. So I decided to do it, and I told the surgeon on the loop that we are going to do the data take over the volcano, that his dietary concerns are not equal in terms of return. Plus, everybody knows ya’ll have the wrong diet. Everybody knows the best diet for in-flight work is a bolo­gna sandwich.

“The surgeon kind of imploded. I think he thought I had impugned him, and so he stopped objecting. We did the data take, and it was wonder­ful. Lunch was about a half-hour late. It was no big deal. I believed that. I believed it didn’t make any difference. We got all of that done.

“A curious thing happened the next day. When I came on shift there on my console was a bologna sandwich, which honest to goodness was a foot and a half long and six inches wide and had at least an inch of bologna in it. Nobody ever ’fessed up to where it came from. So I don’t know whether the surgeons did it or somebody who had heard the conversations. I always hoped that the surgeon did it. But it changed the dynamic. We got along better after that. Not a lot, but. . .”

During flight, this issue was greatly alleviated by the addition of another level of coordination within the science community. The initial structure in which the various disciplines each advocated their own concerns to Mis­sion Control was putting substantial strain on the flight directors, who had to weigh and balance those concerns. “So what we did was invent a tsar—a ‘science tsar,’” Shaffer explained. The first science tsar was Robert Park­er, a member of the second group of scientist astronauts. “At that point we refused to listen to all those people any more; we only listened to Robert. He brought the finished product into the planning shift, which we then imple­mented. That all worked well in the planning cycle, though it didn’t help a lot if you ran into something happening in a real-time conflict, because Robert wasn’t always available to us.”

At one point during Skylab mission preparations, Shaffer said, the ulti­mate authority of the flight director for dealing with real-time situations as they occurred was challenged by a visitor from NASA headquarters. “This is another one of those stories people don’t know anything about,” he said. “During the Skylab 2 sims [simulations], this guy showed up, badged and everything, and walked into the control center. Because I was launch flight director, I was running the sims.

“And he said, ‘Where’s my console?’” Shaffer said. “And I said, ‘Who are you?’ He said ‘I’m the mission management representative from Washing­ton.’ I said, ‘What do you do?’ And he says, ‘I am from NASA headquarters, and I have the final say in all of the decisions we’ll make in this program.’ And I said, ‘Well, I find that pretty interesting. I’ve never heard of you before, and there’s really no place in my flight control team for you to do that, par­ticularly during a dynamic phase. Frankly, you’ll be a lot more trouble than you’re worth no matter how good you are.’ And he says, ‘Be that as it may, I am here to stay.’ And I said, ‘Very well.’”

Shaffer said that he considered calling director for flight operations—and NASA’s first flight director—Chris Kraft to come deal with the situation, con­fident that the original “Flight” would back him up. However, he decided to try and handle the problem himself before resorting to calling for help. “I went back to my console and got on one of my secondary voice loops to the simulations supervisor, and said ‘I want you to give me the “Apollo tape case,”’” Shaffer said. “So Sim Sup says, ‘Why am I doing that?’ I said, ‘Because I’m asking you to.’ And he said, ‘I got it.’

“So he gave us that case and things really went to hell in a hand basket. The tape was the source for all the csm systems failure descriptions and data used for training simulations for the flight controllers and flight crews. We couldn’t tell where we were in orbit after the launch phase, communi­cation was really ratty, and there were electrical problems, computer prob­lems, etc. I unplugged and ran up to his console and said, ‘Tell me quick. . . what do I do now?’

“The guy looked at me, reached up, unplugged his communications set, got up, and walked out. We never saw him again during a dynamic flight phase.” On orbit however, his group was very active via an ad hoc organiza­tion called the Mission Management Team.