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Going boldly: Behind the scenes at NASA’s hallowed Mission Control Center

Apollo vet Sy Liebergot shows Ars how NASA got men safely to the Moon and back.

"The Trench" — the front row of the restored Apollo Mission Operations Control Room
Enlarge / "The Trench" — the front row of the restored Apollo Mission Operations Control Room

HOUSTON, TEXAS—Astronauts have been saying "Houston" into their radios since 1965. The callsign refers in general to the Johnson Space Center in Texas, and the people who answer to it sit in the Mission Control Center, located in Building 30 near the south end of the The Lyndon B. Johnson Space Center (JSC) campus. "Mission Control" has been the subject of movies, television shows, and documentaries for decades. It's usually depicted as a bustling room filled with serious folks in short-sleeved white shirts and skinny black ties who shout dramatically about damaged spaceships while frantically pressing buttons on chunky 1960s control consoles. What is it really like, though, to sit at one of those consoles? What do all of those buttons do?

On a sunny morning in early October, I hopped in my car to find out. The Johnson Space Center is about a dozen miles from my home in League City, up the newly constructed NASA Bypass and down the historic NASA Road 1. After a short drive, my photographer and I were in line at JSC's main gate. We were meeting contacts from NASA's Public Affairs Office, and they were going to escort us further on-site to Building 30 for an Ars "Mission Control" tour. Our mission? Explain the technical details behind how the room operated—and what it was like to sit at a console and answer those calls from space.

The exterior of Building 30, which houses the rooms collectively known as "mission control." The flag on the roof flies whenever there is at least one American in space.
Photo by Steven Michael

One small step

This wasn't my first time in Building 30. I visited JSC with some frequency during my time at Boeing, though not often enough for the feeling of wonder to wear off. Some people are awed when they go to St. Paul's Basilica, others by visiting Disney World. To me, neither place holds a candle to the Johnson Space Center—this is the place where, 50 years ago, men and women helped execute the greatest engineering achievement in all of human history.

The original plan for my visit was simply to tour the one restored Apollo-era mission control room, to take plenty of pictures, and to give Ars readers a good technical understanding of how "Mission Control" worked during the Apollo era. NASA, however, upped the ante when it assigned my tour guide—none other than Sy Liebergot.

Sy Liebergot, Apollo EECOM, with his old desk in the background.
Enlarge / Sy Liebergot, Apollo EECOM, with his old desk in the background.
Photo by Steven Michael

The name should be familiar if you're a fan of manned space flight. Seymour Liebergot, a retired NASA Flight Controller, sat at the EECOM console for Apollo 8, 9, 10, 11, 12, 13, 14, and 15. He was one of the flight controllers responsible for ensuring the safe return of Apollo 13 following the explosion of one of its liquid oxygen tanks (in the film Apollo 13, he's played by director Ron Howard's brother, Clint). Liebergot was present for some of the most monumental moments in space flight, and he was going to walk me through the technical details of Mission Operations Control Room 2. It was like requesting a tour of the Bat Cave and having Alfred show you around the place personally.

JSC looks a lot like a college campus. Situated on 1,600 acres of wetlands between Houston and Galveston, it was constructed during 1962 and 1963, eventually becoming operational in time to shepherd Project Gemini into space. One hundred buildings sit scattered across the property, with the main cluster along NASA Road 1, interspersed with parking lots and neatly maintained green spaces. With the exception of a few recent additions, the buildings of JSC appear every bit the product of their era: 1960s modernist, most mixing terraced concrete and glass. The corridors look like they should exude the odor of decades of cigarette smoke, but the federal government's "no smoking" policy has been in place long enough that most smell faintly of stale coffee instead.

Building 30, which was recently named the "Christopher C. Kraft Jr. Mission Control Center," is a tall and mostly windowless structure, three stories in two wings, joined by a central lobby. Building 30 houses several different "mission control" rooms, which are officially called Flight Control Rooms (FCRs, pronounced "fickers"). When the building was first made operational in 1965 there were a pair of control rooms, then called Mission Operation Control Rooms (MOCRs, "mo-kers").

The MOCRs served NASA through the Shuttle era. The room that housed MOCR 1 has been remodeled and repurposed several times; it is currently used as the International Space Station FCR. MOCR 2, which was used for almost every Gemini and Apollo flight, was restored to its 1960s-era appearance after retirement in 1992. It is now a registered historic landmark.

Security doors leading to Building 30's Mission Operations Wing.
Enlarge / Security doors leading to Building 30's Mission Operations Wing.
Photo by Steven Michael

MOCR 2 is on the third floor of Building 30's Mission Operations Wing. The other floors house the Shuttle and station FCRs, as well as FCR support rooms (called MPSRs, for Multi-Purpose Staff Rooms) and office space. The first floor used to house the Real Time Computing Complex, or RTCC, which during Apollo consisted of five IBM System/360 mainframes and their support equipment. As we'll see, the RTCC was a vitally important part of the MOCR's operations.

A portion of the Real Time Computing Complex on the first floor of Building 30. Today, this is all regular office space.
PHO-FAM001 - Familiarization Manual, Mission Control Center Houston
Coffee nook, directly behind MOCR 2.
Enlarge / Coffee nook, directly behind MOCR 2.
Photo by the author

After passing through the security doors, Liebergot and I rode an elevator up to the third floor. We walked through high-ceilinged corridors with raised floors covered in rubberized tiles, an arrangement which would be familiar to many IT workers. MOCR 2 occupies the central area of the floor, around some corners and past a low alcove containing lockers and a coffee machine. To enter, we walked up a side ramp much like you would find in a movie theater with stadium seating. MOCR 2 is indeed about the size of a small theater—in fact, the room is sometimes used by NASA to screen Apollo 13 and other space films for selected audiences.

The iconic Ford-Philco-designed consoles are arranged in four tiers stepping down from the rear of the room, separated by a glass wall from the visitor's gallery and a pair of press booths. The room is dimly lit by recessed fluorescents, and Sy informed me the room was kept even darker. That way, it's easier to see the console displays.

MOCR 2, from the top row next to the DoD console, looking across at the left front rear projection screens.
Photo by Steven Michael

Once our NASA contact cleared out some picture takers and shut the doors, MOCR 2 was suddenly cloaked in silence. I could feel the ghosts. Here, in this very room, sitting at these sage-colored consoles, 30 years of manned space flight happened. It felt very much like standing in a cathedral—except that this room wasn't just built to talk to the heavens, but to actually visit them.

98 Reader Comments

  1. Just adding my voice to the multitudes - fantastic article - one of my favourite reads. And I found the whole thing quite emotional. Great last line too
    704 posts | registered
  2. Mr. Hutchinson:

    Sir I'm of the opinion your article smacks slightly of revisionist history. My recall as an ex Univac employee, the Apollo mission was flown on a 4X4 Univac 1108 multiprocessor with 256 (36 bit) words of memory. It used the FH432 drums with 4.4 ms rotational delay. With elevatoring, the average FH432 latency was reduced to .5 ms for a loaded system. There was nothing like the Univac 1108. True, the CDC 6600s were quite fast, but they didn't have a good operating system. It was more a question of unmanaged raw computing power.

    I was working at Boeing in Seattle in 1964 when we simulated the Apollo moonshot on an IBM 7094. It took almost 18 hours of compute time.

    Boeing bought lots of IBM 360s. Problem. They didn't have an operating system. Boeing wrote their own IBM 360 operating and IBM purchased it. No, IBM was way behind the curve on operating systems and hardware in the 60s. Their big thing was a 7044-7074 HASP system with the 7044 doing card to tape and the 7094 doing the calculations. We replaced many of those systems with multi-processor Univac 1108's.

    Bruce T. Prendergast
    2 posts | registered
  3. 256K words, not 256
    2 posts | registered
  4. YodaOfTheNorth wrote:
    Mr. Hutchinson:


    If I'm guilty of revising history, it's through ignorance, not intent. My source on the contents of the RTCC is chapter 8 of Computers in Spaceflight: The NASA Experience, which is listed at the bottom of the feature under "Further reading". It says:

    Transition to Apollo

    Although the four remaining 7094 computers continued to support flight operations through the first three Apollo (unmanned) missions, IBM used the first replacement 360 to begin software development for the Apollo lunar flights. As in Gemini, two spacecraft, the command module (CM) and the lunar excursion module (LEM), needed support, with five computers each contributing to the overall system. Again, LCS provided added memory. Unfortunately, all the software could not be moved directly from one machine to the other due to the change in operating systems. The new operating system for the series, OS/360, had the multitasking capability developed during Mercury days but operated primarily in batch mode. Many programs could be entered, either by cards or through remote entry from terminals, and run together, but not in real time. The priority-interrupt [255] provisions on the standard operating system were not sophisticated enough to handle the sorts of processing Apollo needed. Beginning in 1965, IBM modified the operating system into RTOS/360, the real-time version55. Extensive use of modularization helped in the transition. Separately compiled subprograms in FORTRAN, moreover, could be moved to the 360 with relative ease, but the assembler-based code had to be modified. This work continued for nearly as long as it took to get the original system operating, even though the architecture remained essentially intact.

    One problem would not go away: memory. Each 360 had 1 million bytes of main memory, about four times the size of 7094 main store. A further 4 million bytes of LCS was added to each machine56. Even with some of the NETCHECK functions transferred to the new twin 360s in the Goddard Real-Time System (GRTS) and with seldom-used programs such as the radiation dosage calculator and ground telescope pointing program permanently located off-line, memory use rose to match the additional space. Simply meeting the requirements for ascent filled the main store57. At this time, NASA's Lynwood Dunseith, who had worked on the ground software since Mercury, realized that the worry over memory was causing programmers to develop idiosyncratic, "tricky" code in an effort to save a few words58. Dunseith knew the danger of that attitude, since it made the programs even more complex than their absolute complexity warranted. During the period he managed the software development, he tried to reduce the dependence on such expedients. It helped him that the 360s made it possible to develop significant parts of the software in FORTRAN59. Although FORTRAN is not as easily readable as some other procedural languages, it far exceeds 360 assembler in understandability.

    As the Apollo system moved into the operations phase the use of the Dynamic Standby Computer waned. During the first manned flight, Apollo 7, the Mission Control Center used a single computer for just under 181 hours of a 284-hour support period, which included countdown and postflight operations60. During Apollo 10, a dual spacecraft flight with LEM operations near the moon, the plan was to use the standby for 5 hours before a maneuver. Therefore, on only six occasions in an 8-day flight would there be two-computer support. To assist an off-line standby in coming to the rescue of a failed primary, operators made checkpoint tapes of current data every 1.5 hours. A failure of the Mission Operations Computer occurred at 12:58 Zulu on May 20, 1969. By 13:01, the standby had been brought up, using a checkpoint tape made at 12:0061. No significant problems resulted, which is actually a good summary of mission control operations throughout the Apollo era, Skylab, and the Apollo-Soyuz Test Project.

    I don't deny your memory or experience, but that's what the source says. None of the folks I interviewed during the research process for this article were super-familiar with the RTCC's systems, so I fell back on NASA's documentation for that info.

    Last edited by pokrface on Fri Nov 02, 2012 10:47 pm

    19638 posts | registered
  5. Read this the other day; didn't have time to post a comment. Incredible article, THIS is precisely the reason I read Ars. Like many others, I imagine, revealed a number of facts I didn't already know, despite reading everything I have been able to find about NASA/Mission Control/Apollo for years.

    Also, Lee, thank you for the link to Challenge To Apollo. I've read a decent amount about the Russian space program, but this is most certainly THE definitive guide.

    Anyway, again, amazing job. Your passion for the subject is incredibly obvious throughout, this exudes incredible quality!
    298 posts | registered
  6. Pokrface wrote:
    Bad Monkey! wrote:
    I always wondered how they created the seemingly ahead of their time display readouts, and now I know!

    In researching the technology, that was the part that shocked me the most. Everything else was reasonable--big mainframes, no software controlled panels, all hard wiring, that kind of thing. But the display stuff threw me. I had to read and re-read that section of PHO-FAM001 over and over again to make sure I was understanding it right, and even after that I sought out some corroborative info. Sy's descriptions clinched it. It really was that crazy--slides and CRTs, filmed by a video camera. Totally wild.

    The internal NASA Video system was B/W, 900 line interlaced 60Hz frame-rate video. That's how they were able to make the displays look so relatively crisp. All of the cameras used enhanced vidicons instead of the former image Orthocons used previously. Typical broadcast cameras of the day were using 3 vidicons with color filters for color video. Video from Apollo 11 was 10 fps, about 400 lines B/W video which had to be translated to 900 line video used on the displays.

    Later Apollo cameras used color sequential filters that operated at 30 fps with each filter getting a third of the frame count. Video was heavily compressed to fit within the bandwidth available on the high-gain dish system on the SM and deployed on the lunar surface. Video received on earth was reintegrated into 30 fps NTSC and 25 fps for SECAM and PAL. It was "frame synchronized" by having a video camera shoot pictures off a b/w monitor or scope face. It really was the only way to do it.

    I wasn't working at the time but my dad wrote the tech manuals for the Apollo 11 frame synchronizer used to convert 10 fps 400/450 lines to 60 Hz 900 line B/W. It required 3 or 4 6 foot racks of hand-wired circuit boards built out of discrete transistors, diodes and passive components (It was before the integrated circuit was available for most functions). It was truly a single use/purposed device. It was never used again.
    1263 posts | registered
  7. Nice job. More like this, please.

    Some textbook work here (and I only mean that in the best way) - talk to a guy on a tour, then mix the anecdotes and personal feelings about the tour with an excellent history lesson. You should be very proud of this piece, Lee.
    2751 posts | registered
  8. I've just got round to reading this, and it is a *superb* article.

    Will an American land again on the moon within the next 100 years? I honestly do not know. With the state of the US economy, the number of families on the poverty line, the amount of remaining US resources squandered on the military, I cannot see the Mars mission surviving either.

    With the ever-increasing amount of basic research coming out of China, my money is on them to take over Space within the next 20 years. As it is, if I am proved wrong and the US returns to the Moon, or goes to Mars, any US rocket will be built of Chinese components.

    BTW I'm not American nor do I live in the US.
    1837 posts | registered
  9. Super digestable and intrinsically absorbable write! Why do we all meme-synch and feel great reading this? Those `Can Do' crew-cuts and white shirts? K+E bamboo slide rules?

    NASA history archive has gigabytes of fantastic Apollo and on++ pdf's, crumbled, coffee stained facsimile pdfs, astronaut walk-thru's, lunar landing module -dashboard -schematics programmer's manual, those repeater ship illustrated guidebooks, etc.

    for more CAPCOM recap:
    1 post | registered
  10. I was on the Blue Team in Mission Control, broadcasting from the PAO console (public affairs), first console on the left in MCC... Today my console... and the entire Gemini/Apollo mission control room... is a designated historic site. A distinct honor, but knda makes me feel old...
    1 post | registered
  11. <<<Andrew>>> wrote:
    Another dramatisation, but I recommend if you have not see it look at "The Dish" about the role of a radio telescope in relaying some of the Apollo 11 pictures and telemetry back to earth

    I also recommend this movie, but with one caveat: it's only loosely based on fact. The whole subplot about losing power and the tracking computer, and then lying to NASA (and the US Ambassador) about the problem, is entirely fictional.

    While it made for a highly entertaining movie (I laughed as hard as anyone), everyone involved with Apollo, regardless of their location or nationality, was far too professional for such a thing to actually happen.

    See for the real story of Parkes and Apollo 11.
    13 posts | registered
  12. e3pi wrote:
    crumbled, coffee stained facsimile pdfs, ...

    Yeah. But some of those things were better left in the past: all those ashtrays. Seems like everyone smoked in those days.
    13 posts | registered
  13. redtomato wrote:
    Indeed. I snarfed copies of all the photos.

    I wonder. One of the main reasons we got the Russians involved in the ISS was to give their military-industrial complex something to do besides building missiles and pointing them at us.

    Maybe a Mars mission would give our military-industrial complex something more productive to do, while again making the United States the envy of the world rather than something so many now resent.
    13 posts | registered
  14. bobbutton wrote:

    You should contact the author of this article. I'm sure he'd love to speak with you.
    17327 posts | registered
  15. Pokrface wrote:
    Danathar wrote:
    I don't think I saw it, but who (company and engineers) are credited with the overall design and architecture of the room? The fact that the whole shebang works in mission control is a miracle.


    I've taken the MSFC (It'll never be the Johnson Spaceflight Center for me!) tour several times.

    What surprised me when I first saw Mission Control (and every time since then) is how small the room actually is. From the TV shots at the time, and in the movies since that time, you get the feeling it is a huge room. It is large, but not as big as the TV (or movie) screen makes it out to be.

    In any event, great article!

    [edit: spelling]

    Last edited by fgoodwin on Thu Apr 10, 2014 10:03 am

    4882 posts | registered
  16. hsir135 wrote:
    GREAT article with in depth writing. You were fortunate to have Sy along to add the human spirit - personal experience element that is so enriching.
    I grew up with the Space Program. When I was in kindergarten, my mother let me stay home from school to watch John Glenn orbit the earth 3 times in 5 hours. He returned a national hero. And when Apollo was fully crancked up, Saturn V launches seemed almost a daily routine. When you look at the ground support equipment described in this article, and combine it with the incredible magnitude of the Saturn V rocket design and construction, the scope of engineering, materials development and resources is stunning. With the millions of componets required for a Saturn V, there must have been a LOT of systems to monitor. One of - if not the - greatest feats of 20th Century engineering.
    It makes me wonder about todays world of technology. If we were to apply it to a moon launch today, how much less personel, equipment and cost would there be involved. The control room for the Ares I rocket launch had so few personel with very compact computer controlled systems compared to the rows and rows of technicians and consoles for Apollo launches.
    Thanks again for a great article about an era when we made bold moves. I'm sure Paul Harvey would have said; "and now you know the rest of the story."

    I could be mistaken, but I think the actual launch systems (the rocket and all the associated systems) were monitored by the Marshall Space Flight Center in Huntsville, AL and by the Kennedy Space Flight Center at Cape Canaveral. It made sense to locate Marshall in Huntsville since the Army's Redstone Arsenal was already there.
    4882 posts | registered
  17. Great article. I'm too young to remember Apollo, but I did work for Ford Aerospace and Loral and Lockheed-Martin on the mid-1990s new mission control center builds. Taking a little time off to visit FCR-1 probably was something everyone on my team did. I still recall walking into it, walking up to the FLT station and sitting in the 1950s chair there - thinking "I'm not worthy."

    Just watched the Orion 1st flight test launch - and I don't see the FCRs that we built at JSC and around the world (there are POCs at most NASA centers, in Russia and a few other locations) which can be provided with real-time data for any mission.

    Does anyone know which of the old FCRs is being used by the Orion program? Walking into Bldg 30S from the parking area (also near the Space Center Houston tour entrance), is the Orion FCR left or right on the 2nd floor? I'd guess it is right since there aren't any doors down by the front of the room but the lack of consoles that we build for ISS is confusing me. Flat screen monitors really do provide more desk space. ;) I knew about the 4 FCRs back in the mid-1990s - 2 in the newer building and 2 in the older part (Apollo and the DoD FCR upstairs).

    By the way, I was part of the "Nifty Fifty" group creating displays for every FC position. Miss the DEC Alphas - never saw any later in my career. Anyone know which computers are being used primarily on the FCR systems these days?

    Update: found this link which explains how the FCRs have been re-purposed. Seems Orion is running out of the "blue-FCR" from the ISS days for the first test mission. They've done enough redesign in the front and back to make it hard to recognize, but I didn't spend most of my time there - I was in either the FAO MPSR or over in Bldg 12 in the ISC lab slinging code for 12+ different OSes. To answer my question above - turn right after entering 30S.
    2344 posts | registered
  18. A very great article. Thank you to Ars.
    My earliest memory is actually seeing Neil stepping out to the moon. I was 4½ at that time.
    1 post | registered
  19. I've just discovered this beautiful and informative article as well as another by the author about the Apollo mission control room. Both incredibly readable and better able to describe the atmosphere and technical achievements of the Apollo missions. Reading these has made JSC another of my goto places if ever I visit the US! Thank you
    1 post | registered

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