“Our whole objective was to test the equipment to make sure it was capable of doing what it was designed to do,” said Manley, “and we had to make sure all the data streams came through the telemetry. They couldn’t fly with an instrumentation cable trailing from the spacecraft down to Earth, so it all had to be telemetered down.”
The concept of test engineering was a relatively new profession, so they sometimes had to invent the technology and equipment to do their testing. “Nobody had any experience in this because it was so groundbreaking,” said Manley. “From my standpoint, the opportunity to work on Apollo came because I just happened to have the right background at the right place at the right time.”
While working on Apollo was undoubtedly exciting and challenging, the pressures of meeting schedule and performance demands from NASA meant office politics often came into play.
“The slightest little things became a mountain from a molehill,” Manley said. “I didn’t like the politics, because I’m a doer and I don’t like to play games. I’d get in trouble sometimes because if I ran a test without the holy-water blessings of the management, I’d get my backend chewed.”
Getting the first manned Apollo spacecraft—known as Spacecraft 012—ready for the first flight, Manley answered questions for North American and NASA engineers, and he regularly saw Grissom, White and Chaffee and other early Apollo astronauts as they came to Downey to check out their ride to space.
“They followed the construction of their spacecraft,” said Manley, “and if they wanted any changes made, they told North American and NASA design engineers. They weren’t encumbered with a lot of paperwork. We’d provide real-time data for the astronauts or anyone who needed it, and our function was to give them a quick way of getting information.”
North American had planned to ship Spacecraft 012 from Downey to Kennedy Space Center in early August 1966, but continued problems with a glycol cooling system in the environmental control unit caused a delay. Since it was a Block I, which was a heavier version of the CSM, Spacecraft 012 could only be flown in Earth orbit. The spacecraft arrived in Florida on August 26, 1966, with much fanfare. It was protected by a special cover, emblazoned with “Apollo One,” which was the astronauts’ preferred term for their mission, although NASA still officially called it AS-204.
Workers at North American Aviation in Downey, California, build Spacecraft 009. Credit: NASA.
Test facilities at North American Aviaition. Image courtesy of Rich Manley
Service Module RCS Quad Panel and tanks. Credit: NASA.
OTHER SYSTEMS WERE THREATENING delays of the first crewed Apollo launch, and one issue in particular caused considerable headaches at MSC since Apollo couldn’t fly if the problem persisted. During vacuum chamber tests, the small steering rockets for the Apollo spacecraft started blowing up.
“The reaction control engines are on the outside of the SM and the LM,” said Norman Chaffee, “hanging just inches from the side of the spacecraft outside wall. So, if one blows up, it acts like a hand grenade, creating a lot of shrapnel.”
A thruster explosion during a spaceflight could be catastrophic. Therefore, the explosive nature of this problem meant that everyone at NASA—in particular the astronauts—took a high interest in the details of the issue, especially when the Reaction Control System (RCS) thrusters kept exploding during repeated tests, for months on end. Management in the Propulsion and Power Division instigated a twenty-four-hour-a-day test regimen to figure it out.
Reaction Control System during a test at the Manned Spacecraft Center. Credit: NASA.
On the SM, sixteen of these metallic, bell-shaped thrusters hung in clusters of four, spaced evenly around the spacecraft’s outside barrel. These thrusters allowed for orientation of the vehicle in any desired direction just as an aircraft’s elevators, ailerons and rudder control pitch, roll and yaw. Marquardt Company in Van Nuys, California, manufactured the thrusters and they, too, were working frantically to solve the problem of unexpected explosions.
After several months of dead ends in trying to understand the problem, Norman Chaffee and Henry Pohl wondered if they could find a way to look inside the combustion chamber as the thrusters fired to see what was going on. The chamber was slightly smaller than a soda can and made of high–melting point metals, but they constructed a new combustion chamber out of clear plexiglass. They set up the see-through thruster and a camera inside a vacuum chamber and fired the thruster while taking high-speed photos—twenty-five thousand frames a second—of the initial few milliseconds of firing. They gathered temperature and pressure data as well.
“The heat input from one of these short pulses was low enough that the plexiglass would last quite a long time,” Chaffee said. “And only if we turned the engine on and just let it run would it eat up the plexiglass fairly quickly.”
But it turned out they didn’t see much, and even with higher-speed film, they didn’t find any anomalies in the thruster. But the plexiglass thrusters blew up too. “We blew up lots and lots of plexiglass chambers without getting the data that we wanted,” said Chaffee, “but we finally documented the formation and buildup of a gooey, yellowish-brown gunk that would collect in the rocket engine.”
The gunk seemed to only form when the fourteen-millisecond thruster firings came in short spurts with long periods of time in between; occasional long, extended bursts appeared to eliminate the gunk. For reasons they could never adequately predict, at some point a critical mass of the gunk would collect and a short pulse would cause detonation.
“When it got to critical mass, it didn’t just burn,” said Chaffee, “it detonated. So it was an actual explosion.”
To find out more, Pohl arranged to put the RCS thrusters in a long-duration test in a vacuum chamber in MSC’s Thermochemical Test Area. They conducted a fourteen-day simulated mission, firing the thrusters in a manner that duplicated a spaceflight to the Moon and back, with about 175,000 firings of each thruster. But during the test, technicians noticed the inside of the vacuum chamber was getting coated with the same gunk that they’d seen inside the engines.
“We went in the vacuum chamber and took some samples of this stuff,” Pohl said. “One of the guys put some gunk on an anvil and tapped it with a hammer. It popped like a cap pistol going off. We knew we had to get this stuff tested to find out what it was.”
Pohl put some gunk in a vial and told Chaffee to take it over to the transportation office and ship it up to the Bureau of Mines in Pittsburgh for analysis. Chaffee soon returned to Pohl’s office, not sure what to do.
“Can’t ship it,” Chaffee said. “We’ve got to find out whether it’s a Class C explosive or not before we can ship it.”
“Now how in the world are we going to find out if this is an explosive unless you get it to the Bureau of Mines for them to test it?” Pohl asked.
Chaffee knew this impossible circular discussion didn’t have an answer.
“Well, I know how,” Pohl said determinedly. “Put this vial in your briefcase and get on an airplane and get up there tonight.”
Chaffee took the small sample, boarded a commercial flight and without incident made it to Pittsburgh. The Bureau of Mines determined the gunk was hydrazinium nitrate.
“You have to hit that stuff pretty hard to get it to detonate, but it detonates,” Pohl said, “and that’s what would happen in the combustion chambers. It would build up in there and explode. So we knew we had to figure out a way to eliminate that from happening.”
In the meantime, the fourteen-day test was still under way and Pohl wanted to continue it to get as much data as he could. Just a few nights later, one of the technicians arrived on shift, worried.
“He came in about 11:00 at night and said that stuff must be getting out of the chamber because it was all over the cars outside in the parking lot,” said Pohl.
LM RCS subsystem in a vacuum chamber test in Building 353 at the Manned Spacecraft Center in Houston. Credit: NASA.
Everyone
ran outside and found several cars coated with a yellowish-brown residue. One of the technicians took the paper wrappers for his homemade cigarettes out of his pocket and started scraping up the residue to gather some samples.
“The guy in charge of the test wanted to shut everything down,” Pohl said, “but we only had a day or so to go, and I wanted to keep going to the end.”
Pohl agreed to sign a statement saying he’d take responsibility in case any explosions occurred and said he’d get a chemist to look at the residue in the morning to confirm what it was.
The next day chemists from Rice University and the University of Houston arrived to look at the residue collected in the cigarette wrappers. The scientists stared into the microscopes for what seemed an eternity to Pohl. Finally, one of them straightened up.
“You know,” he said, “if I didn’t know better, I would say that was pollen.”
Sure enough, the coastal prairie behind MSC was rife with late-summer flowering goldenrod and ragweed, and the strong northwest breeze the evening before drifted the yellowish-brown pollen across the parking lot.
“Son of a gun,” said Pohl, “that’s what it was. It had nothing to do with what was in the chamber, but it looked the same.”
Armed with the knowledge they weren’t going to blow up Houston, along with the data from the Bureau of Mines and the fourteen-day test, Pohl, Chaffee and the rest of the team finally determined the gunk came from a unique chemical reaction between the propellants when the chamber was cold.
“Most of the two propellants did mix and react as intended during each pulse,” said Chaffee, “but in a vacuum and low temperatures, the last small amounts of fuel and oxidizer didn’t react completely, and instead joined together to form this thick, gooey gunk. When enough of this stuff accumulated, it was sensitive to sudden high pressure and temperature, and inevitably a pulse of sufficient energy caused it to ignite and explode.”
The simple solution came in adding two small electric heaters to keep the thrust chambers at a consistent, warmer temperature. The warmth caused the gunk to evaporate. After the heaters were installed, an Apollo RCS thruster never exploded again. This system was ready to fly.
FRANK HUGHES’S HEART BEAT LIKE A hammer as he held on for dear life in the passenger seat of a blue 1966 Corvette convertible. Outwardly, he tried to appear as though racing down a gravel road near Cape Canaveral at 85 miles per hour (137 km/h) was no big deal, because at the wheel was Gus Grissom: astronaut, prankster, speed demon. Grissom made a quick 90-degree turn onto a two-lane road, barely slowing down, tires squealing, and he then floored it to about 120 miles per hour (193 km/h), heading toward the freeway.
He looked at Hughes with a big grin. “Are you having a good time?”
“Oh, yes,” Hughes said, keeping his eyes staring straight ahead while his hair streamed straight back.
Grissom turned onto the freeway toward Merritt Island, now going 140 miles per hour (225 km/h). Hughes’s only wish at that moment was that ’Vettes had seatbelts.
The two men had just met; it was Hughes’s first day of work at Kennedy Space Center. He needed a ride, and Grissom was happy to oblige, giving him the ride of his life.
“Gus just wanted to check out the new guy to see how he’d do,” Hughes said. “He was something else, always pushing the limits. All those guys were the same; they really liked to play. They would get a new car every six months, as soon as the ashtrays were full or whatever. They had a good thing going with one of the car dealerships in Houston.”
Over the years, Hughes would ride in many more Corvettes and send astronauts on crazy rides of their own in the Apollo simulators. He technically worked for MSC but was assigned to work at the Cape to operate the new Apollo trainers, just like the ones in Houston. That morning, Hughes had arrived at the Kennedy Space Center at the same time a semitruck dropped off a conglomeration of gigantic boxes containing the CM simulator. Both Hughes and the simulator took up residence in Building M7-409 at the Cape, a brand-new building that was seemingly just waiting for the two of them.
“That building—and the simulator—were like my second homes,” Hughes said. “I was there all the time.”
The first few months, everything about the simulator posed a challenge: getting it assembled, learning how it operated and (the biggest challenge of all) keeping it working.
“At first, we couldn’t get it going,” Hughes said. “Gus always called it a train wreck because of how it looked with all of this visual gear hanging all over it. But one day he was so upset with it not working, he hung a lemon on it.”
Technicians at Kennedy Space Center construct one of the Apollo Simulators. Credit: Frank Hughes.
Most of the problems stemmed from how the flight software needed to be simulated and from the requirement that all the various computers work together. Ideally, one computer should pretend to be the Apollo Guidance Computer (AGC) on board the spacecraft; but functionally, that was almost impossible and the software was always changing. Hughes began continually working with the people at the Instrumentation Lab at the Massachusetts Institute of Technology (MIT) to get the latest updates.
By the late summer of 1966, Grissom, White and Chaffee were using both the simulator and the real spacecraft to train for their flight. Spacecraft 012 arrived at Kennedy Space Center on August 26, certified by North American as mostly ready for the first Apollo flight.
While the simulator wasn’t working very well, the CM had its issues too. And the problems seemed to tag-team: When problems arose with the communications systems in the real spacecraft, the simulator’s communications system worked well. “On the other hand, when he turned on a computer over in the real spacecraft,” said Hughes, “it worked pretty well because it had the real computer, where ours was still trying to fake this thing into thinking it was the computer. Gus, Ed and Roger would say, ‘We’re frustrated in all directions.’“
One aspect of the training worked perfectly from the start: Hughes could share his knowledge of astronomy with the crews. He had planned to be an astronomer, but during his sophomore year at St. Mary’s College in California, Lyndon B. Johnson visited the campus and gave a speech about the space program. “He just converted me,” Hughes said. “The astronomy thing just went up in a puff of smoke, and I knew I was going to work on Apollo. I finished my degree in ‘65, and now, here I am.”
The Simulation team at Kennedy Space Center. Left to right: unknown, Dan Blend, Joe Sundra, Maurice Walters, Dave Struck, Glen Larsen and Frank Hughes. Credit: Frank Hughes.
Hughes taught the astronauts the fifty-one stars they needed to know to use the optical navigation system that was part of the AGC. Star sightings were used to align the platform of the guidance system and, if the astronauts knew how to navigate by the stars, they could get to the Moon and back—even if they lost communications with the ground. Hughes took the astronaut crews to Morehead Planetarium at the University of North Carolina, but teaching them about the night sky was even better under the real thing.
“We’d take them somewhere out in the boondocks in Florida,” said Hughes, “and make sure they could still find Canopus, Altair and Polaris, and every one of the fifty-one stars they needed to know. We taught them all the astronomy tricks like ‘Follow the arc to Arcturus’ and ‘Speed on to Spica.’ We had a checklist and they had to find them all. That worked really well.”
But over the next few months, as Hughes became a self-trained expert on the simulators, he and his cohorts got them running like well-oiled machines.
“Luckily, we were all pretty quick studies,” he said, “but I was single and all I had to do in a new town was read the damn instruction book inside and out, every night at the kitchen table. And of course, I had questions, so I’d go find the person who knew something and get an answer.”
He trained himself by getting to know all the systems, starting with the electrical systems, which were connected to the fuel cells, which were connected to the environmental control, whic
h was connected to the computer and communications. He learned everything he could about each system, especially the AGC, and started making trips to MIT to get the latest software updates.
The Apollo Simulators at Kennedy Space Center. Credit: NASA.
By late fall, the Command and Service Modules (CSM) simulator had lost its status as a lemon. The crews were training both in Houston and at the Cape, and Hughes knew that Grissom, White and Chaffee were going to be a well-trained crew for the first flight of Apollo. Whether they would get off the ground before the end of the year remained to be determined.
THE GEMINI PROGRAM CONCLUDED IN November 1966, with the program successfully building a technological bridge between Mercury and Apollo. The missions simulated the length of a lunar round-trip, and astronauts learned how to move about and work during extravehicular activities (EVAs) in their spacesuits. The rendezvous concept was perfected, and the astronauts, flight controllers and mission planners became comfortable with these orbital maneuvers that would be necessary in lunar orbit.
One nagging issue with Gemini needed to be resolved, however: another thruster issue.
“We were experiencing a decay in the amount of thrust from the small ablative thrusters in Gemini,” said Chester Vaughan. “They were supposed to put out 25 pounds (11 kg) of thrust, but over the course of the mission, it would gradually decay and get down to 2 to 3 pounds (1 to 1.4 kg) of thrust. That happened in at least eight out of the ten Gemini flights.”
There was no direct measurement available from the spacecraft showing the amount of thrust at any specific time, but Jerry Bell and Ken Young from the rendezvous team could see evidence of the low thrust in looking at data from a strip chart recorder that tracked all the thruster firings. Gerry Griffin in Mission Control tracked the problem by analyzing the motion of the vehicle.
On the whole, the flight controllers were able to work around the problem because of a redundant system, but everyone wanted to figure out what was going wrong on Gemini
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