NASA considered both these tests as “mission constraints” for the flights of Apollo 7 and Apollo 8, meaning if anything went wrong or problems were uncovered the flight schedule would need to be delayed until the issues were resolved.
The first test, LTA-8, tested the LM, which was of great interest, because windows in the LM had shattered during a cabin pressurization test in December 1967. The LTA-8, a Lunar Test Article—a nonflying test version of the LM—was placed in the smaller vacuum chamber B to undergo four separate tests, from between one and ten days in early May to the beginning of June. Besides the vacuum environment inside the chamber, a bank of specialized lights simulated the light and heat from the sun, while temperatures could also be regulated to the –250°F (–157°C) cold of space. The simulated crew of astronauts, Jim Irwin and Gerald Gibbons, entered the LM in the chamber only for short periods and conducted simulated separation and docking maneuvers. All systems worked well, and the crew experienced only minor difficulties during ingress and egress of the chamber.
The public expressed high interest in the chamber tests, which were covered extensively in the media. NASA issued press releases on each test. With no “disabling anomalies” uncovered, James McLane triumphantly announced, “The craft passed its final preflight tests with flying colors. We have removed the last uncertainty. We’re home free!”
The Apollo Command and Service Modules inside Chamber A of the Space Environment Simulation Laboratory at MSC for the 2TV-1 test. Credit: NASA.
The 2TV-1 test for the CM garnered even greater interest because it would be conducted in the enormous Chamber A, and the crew would remain in the chamber for eight days straight. The test for 2TV-1 (which, in NASA’s acronym-heavy vernacular, stood for Apollo Block II thermal-vacuum) relied on expertise garnered during tests of the Block I CM designs conducted in 1966. This problematic eight-day test with three astronauts included a malfunction of the vacuum depressurization system, problems with the light banks, ice buildup on the heat shield and excess moisture inside the spacecraft. The biggest threat to the continuity of the test came when the urine dump line froze, meaning urine needed to be stored in bags for the duration of the test. The strangest issue uncovered in the 1966 chamber test came from problems with the specialized underwear worn by the crew. The underwear had been designed especially for space travel, but the crew was forced to take the underwear off and stow it securely after it was discovered the material off-gassed poisonous lithium fluorine gas.
But with fixes made and lessons learned, Wren organized a crew of about seven hundred people in the spring of 1968 for the 2TV-1 test to ensure that the CM maintained the proper environment for crew and equipment in the extreme vacuum and temperature of space. With a rotating base, the spacecraft could be turned in the “barbecue mode” to test the passive cooling technique.
First, Wren’s team conducted a three-day test without the crew inside to verify the integrity of the vehicle and the systems. Then, on June 16, 1968, astronauts Joe Kerwin, Vance Brand and Joe Engle entered the CM inside the vacuum chamber. During the next eight days, the crew performed many of the functions as if on an actual spaceflight, including eating and sleeping.
“We hooked up communications and data systems to Mission Control,” said Wren, “with cables running through the underground tunnels, so the crew operated everything as if they were in flight.”
The consoles for operating and monitoring the vacuum chambers in the Space Environment Simulation Laboratory at MSC. Credit: NASA.
Interior views of the Command Module and astronaut Joe Engle during the seven-day manned thermal vacuum test, 2TV-1 in chamber of Building 32 at MSC. Credit: NASA.
The crew tested guidance and navigation equipment, activated and checked out spacecraft systems and simulated engine firings. Meanwhile, chamber operators put the spacecraft through several phases of flight, simulating various temperatures and lighting conditions. Technicians and engineers worked around the clock in twelve-hour shifts, monitoring systems and activities inside the chamber with television monitors and a myriad of control panels.
But all went well. “Those eight days were incredibly fun,” Wren said, “and the biggest problem came from condensation, with everything dripping inside the CM from all the human exhaust.” Engineers instituted subsequent changes to the environmental controls in the real CM.
Kerwin felt the biggest test came when assessing the new fireproof materials, breaking ground to enable the flight of Apollo 7, which would soon be scheduled for early October 1968.
But eight days confined in a vacuum chamber had its challenges.
“We didn’t think of it as being quite such a monumental thing,” said Engle. “We were kind of bored in there, actually. I think I pulled on my hunting and camping skills to live in a confined area. Being confined in a tent while it’s raining for several days with a couple of guys—that was good training for 2TV-1.”
If the crew was bored, imagine sitting at a console for twelve hours during a sleep shift.
“One night, one of these technicians got up from his station and told the guy next to him, ‘I’m going to the bathroom,’” McLane laughed. “He was never seen again. He’d just had enough of it.”
Another evening during the test, Apollo program manager George Low visited the facility and noticed a technician paging through a copy of Playboy.
“You let your guys do that all the time?” Low asked McLane.
“Look,” he replied, “we let them do anything when they’re on a duty station like this, and they might need some stimulus to stay awake.”
WITH THE FIRST CREWED APOLLO FLIGHTS on the horizon, the simulation schedule ramped up. And soon, the Simulation Branch developed the reputation of being diabolical. But that wasn’t their intention at all.
“We didn’t do ‘gotcha’ sims,” said Jay Honeycutt. “It wasn’t our goal to make anybody look bad. Our job was to develop a team that could work smoothly together.”
By 1968, the sim team consisted of about forty people, some specialized in the CSM, others in the LM or trajectory.
“We would divide ourselves up into those positions, but we really were only one team,” Honeycutt said. “It didn’t take forty people to run a sim, but it took about ten, and there were five flight control teams. So, they had us outnumbered.”
No one had time to keep good notes or records, and some sim scripts were written on the back of bar napkins while others were jotted down on paper, only to be misplaced later.
The sims could be a big endeavor, encompassing as many as two hundred people. The ten console positions in Mission Control each had several people in the various backrooms for support, such as the Mission Evaluation Room (MER) and the Staff Support Room (SSR). The SimSup couldn’t give everyone something to do at once because of the flight control team’s pyramid structure. “You couldn’t blow up every console with enough work to keep everyone busy,” Honeycutt said, “because the flight director would go under just from the sheer magnitude of everyone wanting to talk to him at one time.”
The sim team learned how to listen to several conversations at once. Every console position in Mission Control had a voice loop with their back room, and every position could talk to the flight director and hear the crew. The SimSup could punch into a variety of the voice loops and listen to the conversations in order to modulate how all the problems were dealt with. Sometimes the problems might come from a simulator glitch and they’d have to reset and start over.
Some simulation runs lasted the entire day, from 7:00 a.m. to 8:00 p.m., if they were practicing going to the Moon or being in lunar orbit. For shorter events like launches or landings, they would run 8 to 12 cases a day.
Astronaut Michael Collins, Command Module pilot of the Apollo 11 flight, is seen inside an Apollo Command Module (CM) mock-up in Building 5 at MSC, practicing procedures with the Apollo docking mechanism in preparation for the scheduled Apollo 11 lunar landing mission. Collins is at the CM’s docking tunnel, w
hich provides passageway to and from the Lunar Module (LM) following docking, and after removal of the tunnel hatches, docking probe and drogue. Credit: NASA.
“You’d try to figure out the main objective you’d want to accomplish with each one of these runs,” Honeycutt said, “and then what other two or three things you’d want to throw in to make it exciting for a couple of other console positions.”
They conducted two-day sims to give the flight controllers practice for handing things over to the next shift. They came up with sim problems for the entire building, where they would flip an electrical breaker and monitor how long it would take people to track down and solve the problem.
View of Mission Control. The Simulation Control Area can be seen through the glass windows on the far side of the room. Credit: NASA.
The Lunar Module Simulator in Building 5 at the Manned Spacecraft Center. Credit: NASA.
Honeycutt’s favorite sim targeted Steve Bales, the Guidance Officer in Mission Control. Bales sat at the end of the front row—known as The Trench—and the night before an LM landing sim, one of the sim technicians would tie a string to the circuit breaker under the suspended flooring that was connected to Bales’s console.
“Right in the middle of the sim, when Bales was coming up to make this really critical call, we yanked the circuit breaker and took all the power from his console,” Honeycutt said. “Bales just told everyone to move down, and they all just shifted down one console to the left, like nothing had happened, and they did the landing. It was really something to witness, but it was an opportunity to get everybody involved.”
At the end of each sim exercise, the SimSup would hold a debriefing with everyone to provide an overview of how well the flight control team performed or how effective they were in chasing down problems—but these debriefings were always conducted in the spirit of building the individuals into a cohesive team.
The Apollo 4 Command Module, with flotation collar, is hoisted aboard the USS Bennington, recovery ship for this uncrewed, Earth-orbital space mission. The Command Module splashed down on November 9, 1967, 934 nautical miles northwest of Honolulu, Hawaii, in the mid-Pacific Ocean. Credit: NASA.
The prime crew of the Apollo 8 mission training for recovery operations in the Gulf of Mexico. Left to right are astronauts William A. Anders, Lunar Module pilot, and Frank Borman, commander. A team of MSC swimmers assisted with the training exercise. Credit: NASA.
With missions scheduled approximately every two months, the two identical Mission Control Rooms were always busy running simulations for two different missions. In 1968, the sim team usually worked seven days a week, from 10 to 12 hours a day. Three days a week they’d run sims for Apollo 7 and the other three days they’d run them for Apollo 8.
“That left Sundays to figure out what we were going to do next week,” said Honeycutt. “It was pretty hectic sometimes from a family-life point of view. But you couldn’t have blown us out of there with a stick of dynamite. Everyone was having so much fun, and things were moving so fast. Nothing was the same from flight to flight, because every flight had a different set of objectives, and the envelope got expanded on each flight, so there was more to do. It was wonderful.”
ALL OF NASA’S SPACECRAFT UP TO THIS point had returned to Earth by splashing down in the ocean. Therefore, NASA could rely on that rich history of experience when it came to fishing the Apollo CM out of the water and picking up the crew. But Apollo was bigger and heavier than any previous spaceship, so NASA’s Landing and Recovery Division had some challenges to deal with in order to get ready for the first crewed Apollo flights.
“In training for Apollo recovery operations, we didn’t do simulations quite like the astronauts and flight controllers did,” said Milt Heflin, a NASA landing and recovery engineer. “Instead, we had about four or five different mock-up versions of the CM, and one way we’d train was to put them in the Gulf of Mexico using an old flat-bottom Army landing craft. We became very adept at what we needed to do by testing it over and over again.”
NASA worked with the Department of Defense to utilize aircraft carriers for the spacecraft recovery. Swimmers from the Navy Underwater Demolition Team (later called the Navy SEALs) would leap into the water from a helicopter to wrestle a flotation collar around the capsule, pop the spacecraft hatch and help the astronauts make it safely into the recovery helicopter. NASA’s Landing and Recovery Division would work with Underwater Demolition Teams in San Diego and train at the naval base there, as well as on board aircraft carriers.
“We really had a real worldwide force through the Department of Defense to support us,” Heflin said. “The Navy and Air Force would send representatives to the Manned Spacecraft Center, where we would meet prior to every mission, and go over the details of what was required to do the job. Then we would send our teams from the Landing and Recovery Division out to conduct briefings and training on board the ships and at aircraft staging bases that would be conducting the spacecraft recovery.”
The Biological Isolation Garment (BIG) worn during a qualification test. Credit: NASA.
Even though the CM weighed about 12,000 pounds, in the water it acted like a cork, bobbing and weaving amid the waves. The shape and size of this cork presented a large surface area to the wind, causing it to be blown downwind.
“When we would brief a new team of the Underwater Demolition Team frogmen,” said Heflin, “we’d tell them, ‘Now, we know you guys are really strong swimmers, but you cannot swim as fast as this Command Module is going to drift across the surface of the water, so don’t try, don’t even try.’ Sometimes they learned the hard way to not jump out of the helicopter unless they were downwind of it, with the CM heading toward them. If they dropped a little upwind, they could never catch it.”
Heflin said the great thing about using the big attack carriers (like the USS Essex, which would be used for Apollo 7, and the USS Yorktown, which would be used for Apollo 8) was that, as the carrier would come alongside the spacecraft, the giant ship would create a leeward, calm area in the ocean. This made the task of raising the CM out of the water with a specialized crane much easier.
Milt Heflin atop the Apollo 8 command module prior to “safing” (removing hazardous propellants) at Ford Island hangar on Oahu on December 29, 1968. Image courtesy of C. Mac Jones.
“With this being a 12,000-pound object that you’re trying to bring up out of the water, it has a tendency to start swinging like a pendulum,” he said. “And of course, as the line gets shorter, the pendulum wants to swing faster. We would have sailors using tending lines that had been hooked up to the Command Module prior to being lifted out of the water so that as it came out of the water, the sailors could steady it. There was a trick to it, though, and that was probably where we had to train the most.”
Part of Heflin’s responsibilities for the upcoming missions that would land on the Moon included overseeing the development of the Biological Isolation Garment (BIG), a containment suit for the astronauts to prevent any contamination in the unlikely case they had been infected with some sort of lunar life-form. The BIGs would be tossed into the spacecraft after the hatch was opened following splashdown, and the astronauts would stay in the BIGs until they were sealed inside their Mobile Quarantine Facility, which was a specially outfitted Airstream trailer.
To choose the material for the BIGs, Heflin worked with the biological weapons testing facility at Fort Detrick in Frederick, Maryland, as they could ascertain if certain materials would contain a specific size of microorganisms. The experts there recommended a rubber-coated cotton material and designed a coverall-type garment with an attached breathing apparatus, which looked like a gas mask.
Once a prototype suit had been constructed, Heflin decided he needed some additional data on the BIGs, because he was worried about how hot the astronauts would get while wearing the suits and if they’d be able to communicate through the bulky gas masks.
“We had the go-ahead to get the work done and do whatever
we needed to do,” said Heflin. “I had an idea for a test, and one of my colleagues agreed to do it: He put on one of the BIGs, and we had a medical doctor insert a rectal probe, and then we sent this guy in the suit outside to sit in the Houston humidity and sunshine in one of those classic gray government chairs. The doctor was right there, about 5 feet away with a device that would measure this guy’s core body temperature. I’m sure it was almost like torture because he indeed did get hot. But we got data we needed right away and it didn’t cost anything.”
The concern with communications came in particular when the astronauts were getting picked up by the helicopter, where there would be prop wash and noise. Heflin wanted to use a battery-operated microphone apparatus for crew communication, but of course, it needed to be tested first. One of Heflin’s coworkers had a pickup truck with a roll bar, and Heflin convinced the truck owner to stand up in the back of the truck, hold on to the roll bar and stick his head above the cab while wearing the gas mask and microphone. They drove 60 miles an hour (97 km/h) down the street to simulate the prop wash and wind noise. Again, they got the data—and at very little cost.
“Quick and easy always did the trick,” Heflin said. “But I do believe the BIG was the ugliest thing I’ve ever seen anybody ever have to wear. We just hoped it did the job because saving the world from lunar bugs was something nobody ever had to do before.”
Warning system engineer Jerry Woodfill on the far left in the Mission Evaluation Room during an Apollo mission. Credit: NASA.
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