For all the missions, the team needed to compute both nominal (normal) and contingency backup plans for all the things that might go awry.
“Frankly, for Apollo, we spent 80 percent of our time on the what-if contingencies,” said Young, “like having the Command Module perform a rescue if the Lunar Module couldn’t get back from low lunar orbit, which involved a long, complicated sequence that would take hours. The truth about mission planning is, our work involved guarding against and preparing for those one-off, weird, off-nominal events.”
The Rendezvous Analysis Branch was organized under MSC’s Mission Planning and Analysis Division. Since the Mission Planning and Analysis Division encompassed so many areas of study and work, the Rendezvous group found themselves working with several other groups and divisions at MSC. For example, they needed to coordinate with Henry Pohl and the engineering directorate to understand the Reaction Control System (RCS) thruster system in order to incorporate the thruster capabilities into the rendezvous maneuvers.
Engineers at the Manned Spacecraft Center. Credit: NASA.
Additionally—and surprisingly to some—computers and software became a large part of their work, mainly due to the need to combine the spacecraft hardware with the software for the Apollo Guidance and Navigation Computer.
“I really felt the software work we did was as important as anything that I worked with,” said Osgood, “not in doing the coding myself or the equations, but in writing requirements for what needed to be done and then working with the program to look for any bugs in it.”
The Rendezvous team added several different programmers to their team, and software specialist Bill Reini gained notoriety in the rendezvous world for coding a project that came to be known as “The Monster” because it could encompass several different rendezvous methods and numerous other concepts for spaceflight.
“Bill was sort of a reticent person,” Osgood said, “and he’d never write anything down if he could help it, so I wrote his users’ manual for his Monster. Not very many people could run The Monster, other than me, because it was really a chore. But, you know, I’d gotten accustomed to it and had a really good working relationship with Bill.”
With the programmers on board, they could create programs and software—as rudimentary as they were in 1965—and get it done almost immediately.
“We now didn’t have to wait for years and years for somebody to decide that they were going to work on that piece of software,” Osgood said. “And if you’d find problems, you’d take it to the programmer, he’d grumble a little bit, and a few hours later he’d throw some cards on your desk and say, ‘Here. Try this.’“
By cards, Osgood was referring to computer punch cards, the primary method of inputting data to a computer in those days. The digital data represented on the cards came in the presence or absence of holes, lined up in different columns, which the computer could read as ones and zeros. Once a card had been punched and completed, it technically “stored” that information. Groups or “decks” of cards formed programs and collections of data, but they needed to remain in order.
“We actually had a group of people that would keypunch the cards,” Osgood said, “but we were usually a little too impatient, and there was a keypunch machine right here. We knew exactly where we wanted the information to be punched on the card, so we’d have big stacks of IBM cards, take them over to Building 12 and submit them to be run on the mainframe, the IBM 7094.”
The next day, Osgood would get the cards and a printout back, but she could only submit about one run of cards a day, however. So, any mistakes meant it would be a day or two until she could try again. Or if something needed to be changed or added, another day would go by. And if the stack of cards were dropped or somehow got out of order? Start over.
How did they relieve stress?
“We would periodically take off half a day to go down to Galveston and go fishing,” said Bell. “We had lives outside of work, but not much of it.”
In the meantime, the Gemini flights started in earnest in 1965, becoming a link between Mercury and Apollo and paving the way for the ability to land humans on the Moon.
EARLE KYLE WAS RECRUITED FOR another contract-engineering job for Apollo, this time in Minneapolis, his hometown. Honeywell received subcontracts from North American Aviation for several systems on Apollo, some involving analog systems and others using digital electronics, so Kyle’s unique skills continued to be in demand. He worked at Honeywell for a year on a contract and then was offered full-time employment there. His family was thrilled to have the stability of not moving from place to place; Kyle was ecstatic because he could still work on Apollo.
“Sometimes I think I would have paid them to be able to work on this, no joke,” Kyle said. “Holy crap, they were going to let me keep working on the spacecraft that were going to the Moon! It was like a dream come true.”
Honeywell built a rich history of creating instrumentation for military aircraft as well as attitude-control systems and control columns or joysticks. Now, Honeywell and several other companies encompassed under a larger entity called Honeywell Aerospace contributed to the Apollo effort: developing the analog flight computer for the first stage of the Saturn V rocket to keep the entire rocket stack stable as it rose through the atmosphere, and building equipment for the Unified S-Band communications system on both the spacecraft and the ground stations. They also contributed to the Scientific Experiment Package, the instruments that would be placed on the Moon by the astronauts, which would run autonomously for long-term studies of the lunar environment.
Honeywell also developed the stabilization and control system that operated the thrusters on the CM and the LM and built an all-attitude display unit for the CM called the Flight Director Attitude Indicator (FDAI), commonly called the “eight ball” because it resembled the black eight ball in the game of pool. This device monitored the guidance and navigation system and provided a display of the spacecraft’s orientation and attitude. The Honeywell plant in Minneapolis had been built well before World War II but just happened to be situated exactly on the forty-fifth parallel, halfway from the North Pole to the equator. This made it the perfect place to test gyroscopes and accelerometers for the space program.
Kyle worked specifically on specialized ground support equipment called the Bench Maintenance Equipment (BME) computer, which served to test hardware during production in Minneapolis and also acted as ground support equipment out on the launchpads at Cape Canaveral. He also enhanced the electronics for shoebox-size computers that would operate the thrusters and displays on the attitude-control system on the two spacecraft. He worked on refining the digital logic circuits, which figured out which small thruster engine to fire when a command was given either by the computer or by an astronaut using a joystick to control the spacecraft during the flight to and from the Moon.
GEMINI 3
The first crewed flight of Project Gemini launched on March 23, 1963, from Cape Canaveral in Florida, carrying Virgil (Gus) Grissom and John Young in the first US flight with two astronauts aboard. A Titan rocket boosted the small, cramped capsule to approximately 140 miles (225 km) above the Earth, and the crew made three orbits in the 4-hour-and-52-minute flight. The main objectives of the flight were to evaluate the two-man design of the Gemini capsule, test out an improved tracking network and orbital maneuvering system, and to attempt a precision-controlled reentry and landing while evaluating recovery procedures and systems. The mission was considered a success despite a few problems with the thrusters and the parachute, causing them to splash down over 100 miles (161 km) away from the intended landing site. Also during the flight, a surprise appearance of a corned beef sandwich—which Young had smuggled aboard—created a floating-breadcrumb mess.
Launch of the Gemini 3 mission. The spacecraft was nicknamed “Molly Brown.” Credit: NASA.
Gemini 3 astronauts Gus Grissom (left) and John Young. Credit: NASA.
John Young took this picture duri
ng the Gemini 3 mission as the spacecraft passed over Northern Mexico. The large light-brown area is the Sonoran Desert. The Colorado River runs from upper right to lower left. The lower portion of the picture is Mexico, the upper left is California and the upper right is Arizona. Credit: NASA.
Honeywell Bench Maintenance Equipment computer. Image courtesy of Earle Kyle.
It was a heady and hectic time. “Because of the time constraints of trying to get to the Moon before the end of the decade, we worked seven days a week, one-hundred-hour weeks sometimes,” Kyle said. “I was never forced to do that, but if anyone had their heart in this work like I did, they worked as many hours too.”
The gear from Honeywell controlled or interfaced with many major systems, including the large gimbaled engine on the rear of the Service Module (SM). This engine could be moved back and forth and side to side to alter the course of the ship on the way to the Moon and on the return to Earth. Just before the astronauts returned to Earth, they would jettison the SM so only the cone-shaped, heat shield–protected CM reentered Earth’s atmosphere.
“The hardware I worked on helped make sure the entry angle was exactly –6 degrees below the horizon line—plus or minus 0.5 degrees,” Kyle said. “Too low, and the CM could flip over, pointed end facing down, and would burn up. Too high and the CM could skip off the atmosphere and be lost to space. This is one of the most critical and dangerous parts of the mission and all three astronauts’ lives were in our hands. That’s why we worked so hard.”
Every day Kyle would drive to the Honeywell plant, working some days until 2:00 or 3:00 a.m. On long days, he’d catch a nap somewhere within his five-person cubicle—on the floor or head-down in exhaustion on his desk—and then go back to work. If Kyle and his coworkers weren’t solving problems on the design lab floor, they were working with subcontractors around the country who provided the nuts and bolts for all the equipment.
“Each of the supplier companies would have a crew available at all hours, especially if we were working on solving issues,” Kyle said. “We found we could rule the world from our rotary-dial phones by just saying the magic words, ‘I’m working on Apollo.’ And before you could finish the sentence, you were connected to God in that company. They would bend over backward to instantly solve your problem, finding the bolt, diode, piece of glass or whatever you needed and then sending someone on a plane to bring a sack of parts to solve the problem.”
During Apollo, an intricate link developed between all the smaller supply companies and Honeywell, and then Honeywell was linked to the other, larger companies and academic institutions that were contributing the expertise needed to reach the Moon.
An artist’s concept depicting the Apollo Command Module, oriented in a blunt-end-forward attitude, re-entering the Earth’s atmosphere after returning from a lunar landing mission. Credit: North American Rockwell/NASA.
“While the MIT Instrumentation Lab was writing the equations and software that would guide us to the Moon,” Kyle said, “they had passed some of the hardware development of the inertial platform to the AC Spark Plug division of General Motors in Milwaukee, Wisconsin, and we were supplying a subset of components to them. So many weeks I was on the phone to people in Boston or Milwaukee or flying all over the country to some small company in places like San Diego where my expertise in vacuum-tube electronics really pulled the fat out of the fire for a weird failure problem on the big Bench Maintenance Equipment computer. Apollo was an amazing linkage of all these different companies and capabilities across the country.”
FOR THE MIT INSTRUMENTATION LAB, one of the big worries about the Apollo Guidance Computer was reliability. The computer would be the brains of the spacecraft, but what if it failed? Since redundancy was a known solution to the basic reliability problem, Dick Battin and his colleagues suggested including two computers on board, with one as a backup. But North American—having their own troubles meeting weight requirements—quickly balked at the size and space requirements of two computers, and NASA agreed.
Another idea for increased reliability included having spare circuit boards and other modules on board the spacecraft so the astronauts could do “in-flight maintenance,” replacing defective parts while in space. But the idea of an astronaut pulling open a compartment or floorboard, hunting for a defective module and inserting a spare circuit board while on approach to the Moon seemed preposterous—even though this option was strongly considered for quite some time. The added weight of packing spare parts was another issue. A turning point against the in-flight maintenance concept came from Gordon Cooper’s Mercury 9 flight, where several critical electrical systems failed because of fluids floating around the cockpit. Fluids and electronics don’t mix, and it was decided the computers needed to be “potted,” or sealed, to avoid damage from any stray floating liquids.
GEMINI 4
Gemini 4 brought James McDivitt and Edward White on a 4-day, 62-orbit, 98-hour flight which went from from June 3 to June 7, 1965. The mission included the first US spacewalk, by White, a critical task that would have to be mastered before landing on the Moon. Other objectives were to evaluate the procedures, schedules and flight planning for an extended flight, as well as try to conduct station-keeping and rendezvous maneuvers.
At the end of the 20-minute spacewalk, White was exuberant. “This is the greatest experience,” he said. “It’s just tremendous.”
During the mission, McDivitt and White conducted 11 scientific experiments. One investigation involved spacecraft navigation using a sextant to measure their position using the stars, as the Apollo missions would need to do.
Astronauts Ed White and Jim McDivitt are shown in the white room as they enter the Gemini 4 spacecraft atop the Titan launch vehicle at Cape Kennedy, Florida. Credit: NASA.
Ed White floats in the zero-gravity of space during the third orbit of the mission. White’s face is shaded by a gold-plated visor to protect him from unfiltered rays of the sun. In his right hand he carried a Hand-Held Self-Maneuvering Unit (HHSMU) that gives him control over his movements in space. He was secured to the spacecraft by a 25-foot (7.6-m) umbilical line and a 23-foot (7-m) tether line. Credit: NASA.
Another view of White’s EVA. Credit: NASA.
GEMINI 5
For Gemini 5, astronauts Gordon Cooper and Charles “Pete” Conrad set a record with an 8-day orbital flight. The mission tested rendezvous procedures and long duration flights. The plan was to use a device called a rendezvous evaluation pod to test the capability of the astronauts to maneuver the spacecraft in orbit in close proximity with another object, but problems developed with the spacecraft’s fuel cells that precluded the test. However, later, a test was done with the spacecraft reaching and rendezvousing with a specific “spot” in orbit. “Bill Tindall had this concept of doing a ‘phantom’ rendezvous,’“ said Ken Young, “where we just created a phantom target in space, and then did the maneuvers that we had planned to do.” Another objective to demonstrate controlled reentry guidance was not achieved due to incorrect navigation coordinates transmitted to the spacecraft computer from the ground. This caused an 89-mile (143-km) overshoot of the landing zone.
Astronauts Gordon Cooper (foreground) and Pete Conrad leave the suiting trailer at Pad 16 during Gemini 5 countdown at Cape Kennedy, Florida. Credit: NASA.
The Rendezvous Evaluation Pod (REP) in orbit is approached by Gemini spacecraft as seen in this artist’s concept of the REP superimposed on an actual photograph taken on the Gemini 4 mission. Credit: NASA.
Overall view of the Mission Control Center (MCC), Houston, Texas, during the Gemini 5 flight. Note the screen at the front of the MCC, which is used to track the progress of the Gemini spacecraft. Credit: NASA.
A Raytheon employee working on the Apollo Guidance Computer micrologic subassembly. Credit: Draper.
By the fall of 1964, the Instrumentation Lab started designing their upgraded Block II version of the Apollo Guidance Computer (AGC), mainly to take advantage of improved techn
ology. Integrated circuits, which had just been invented in 1959, were now more capable and reliable and smaller: They could replace the earlier designs using core transistor circuits, taking up about 40 percent less space. As quickly as technology had advanced since MIT won the AGC contract in 1961, they felt confident the lead time until Apollo’s first flight would allow more significant advances in reliability (and hopefully reductions in cost). With that decision, the AGC became one of the first computers to use integrated circuits, and soon, more than 60 percent of the total US output of microcircuits was being used for building Apollo computer prototypes.
Workers in the Raytheon factory weaving the small wires for the computer. Credit: Draper.
MIT performed all the hardware and software design while Raytheon built the computer hardware. Douglas St. Clair worked in quality control at the Raytheon manufacturing facility in Waltham, Massachusetts. Since the integrated circuit chips were welded into subassemblies for the AGC, St. Clair designed and installed monitoring devices to determine the temperature of each weld. “The integrated circuits were the shape of two graham crackers stacked on top of one another with ten flat leads—or wires—five on each side, coming out from between the two crackers,” he explained. “The integrated circuits were about ½-inch [1.3-cm] square. There were no solder joints in the computer; all connections were welded and gold plated, which provided a more secure connection.”
While the welding was done by hand, a special machine called an infrared pyrometer measured the flash of light from each weld to ensure the proper welding temperature. Each weld was made under a microscope, and the operator carefully examined each bond after it was made. The circuit boards held ten integrated circuits, and was called a stick. When the operator finished welding, it was passed to a second person for inspection, and then it was given to the shift inspector, who examined every weld before the stick was deemed properly assembled.
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