{{Short description|American computer engineer (1944–2016)}} {{Infobox person | name = Jack Garman | image = Image:Garman pic.jpg | alt = | caption = | birth_name = John Royer Garman | birth_date = {{birth date|1944|09|11}} | birth_place = [[Oak Park, Illinois]], U.S. | death_date = {{death date and age|2016|09|20|1944|09|11}} | death_place = near [[Houston, Texas]], U.S. | alma_mater = [[University of Michigan]], B.S. 1966 | known_for = Saving [[Apollo 11]] mission from abort}}
'''John Royer Garman'''<ref>{{cite web|url=https://books.google.com/books?id=PBLiAAAAMAAJ&q=%22Garman,%20John%20Royer%22|title=Directory of Members|first=University of Michigan Alumni|last=Association|date=1 January 1997|publisher=B.C. Harris Publishing Company|access-date=22 September 2016|via=Google Books}}</ref> (September 11, 1944 – September 20, 2016) was a computer engineer, former senior [[NASA]] executive and key figure of the [[Apollo 11]] lunar landing. As a young specialist on duty during the final descent stage on 20 July 1969 he dealt with a series of computer alarms which could have caused the mission to be aborted.
==Early life== Garman was born September 11, 1944, in [[Oak Park, Illinois]], and attended the [[University of Michigan]] in [[Ann Arbor]]. He graduated in 1966 with a [[Bachelor of Science]] degree in [[Engineering Physics]] and a specialty in [[Computing]].<ref>{{cite web|url=https://www.jsc.nasa.gov/history/oral_histories/GarmanJR/GarmanJR_Bio.pdf |archive-url=https://web.archive.org/web/20080309202531/http://www.jsc.nasa.gov/history/oral_histories/GarmanJR/GarmanJR_Bio.pdf |url-status=dead |archive-date=2008-03-09 |title=Bio: Jack Garman |publisher=Jsc.nasa.gov |access-date=2017-03-09}}</ref>
==NASA career== In 1966, at age 21, Garman was hired by [[NASA]]. He chose to specialize in onboard computing and was assigned to the Apollo Guidance Program Section where he worked with [[MIT]], supervising the design and testing of the [[Apollo Guidance Computer]].<ref>{{Cite news |last=Roberts |first=Sam |date=2016-09-24 |title=Jack Garman, Whose Judgment Call Saved Moon Landing, Dies at 72 |language=en-US |work=The New York Times |url=https://www.nytimes.com/2016/09/25/us/jack-garman-whose-judgment-call-saved-moon-landing-dies-at-72.html |access-date=2022-09-18 |issn=0362-4331}}</ref>
During the [[Project Apollo|Apollo]] missions Garman worked in a support role, advising [[flight controller]]s in [[Mission Control]] on the operation of spacecraft computer systems. A few months before the [[Apollo 11]] mission he suggested that simulation supervisors at Mission Control test how flight controllers might react to a computer error code. [[flight controller|Guidance officer]] [[Steve Bales]] responded to the simulated error by calling an abort, which was found to be a needless reaction for that particular code.
[[Gene Kranz]] told Garman: 'I want you to study and write down every possible program alarm whether they can happen or not.' Garman made a handwritten list of every computer alarm code that could occur along with the correct reaction to each of them and put it under the plexiglass on his desk.<ref>{{cite book|last=Donovan|first=James|year=2019|chapter=You're go|title=Shoot for the moon|publisher=Little, Brown and Company|pages=306–307|isbn=978-0-316-34178-3}}</ref>
===1202=== [[File:Jack Garman NASA award.jpg|thumb|200px|left|Jack Garman receives an award from [[Chris Kraft]] for his role in the [[Apollo 11]] landing.]] A design oversight with the [[Lunar Module Eagle|Apollo Lunar Module ''Eagle'']]'s rendezvous radar led to a near-abort during the [[Apollo 11]] landing, according to engineer [[Don Eyles]].<ref>[http://www.doneyles.com/LM/Tales.html Don Eyles, ''Tales From the Lunar Module Guidance Computer''], doneyles.com; accessed 21 September 2016.</ref>
The radar's Coupling Data Units (CDU), which provided the interface between the radar's hardware and the LM's [[Apollo Guidance Computer|onboard guidance computer]], were powered by a 28-volt 800 Hz power supply, and a separate 28-volt 800 Hz power supply sent energy to the radar's Attitude, Translation, and Control assembly (ATCA) (which physically oriented the Lunar Module). The two power supplies were supposed to operate in [[Three-phase|phase lock]] with each other. However, likely due to inexact language in the LM's design documentation, the system was constructed such that while the two power supplies would always operate at the same ''frequency'' and in a fixed phase relationship, no provision was made to ensure the two supplies were aligned and putting out the ''same phase'' at the same time.
When the LM's rendezvous radar (which tracked the still-orbiting [[Apollo Command/Service Module|Command/Service Module]] (CSM)) was powered up during Apollo 11's descent (a step designed to lessen the crew's workload in case of an abort), the radar's CDUs were energized and took stock of the state of the attached ATCA assembly. By chance, the power-up happened at a moment when the CDU's 800 Hz power supply happened to produce energy that wasn't phase aligned with the ATCA's power (a power-up a fraction of a second earlier or later would have resulted in aligned phases and no problems). The CDUs used their 800 Hz power as a reference signal for interpreting the ATCA's position and orientation, and because the signals from the ATCA were out of phase, this produced readings that were far out of range from what the CDUs expected.
This in turn caused the CDUs to issue interrupts to the guidance computer—12,800 interrupts per second, which consumed about 15% of the computer's available compute time. As the rest of the landing tasks were consuming about 85% of the computer's time, the computer ran out of time to process all of its queued jobs in a single cycle. As scheduled jobs in the computer failed to complete in time, the programs competed for core set memory and vector accumulator registers; eventually, one and then the other were exhausted, and the LM's guidance computer began sounding program alarms and resetting.
The first was a "1202" alarm, indicating an executive overflow and an exhaustion of core sets. Several seconds after the first alarm [[Neil Armstrong]], with some concern apparent in his voice, said, "Give us a reading on the 1202 program alarm." Meanwhile, given his knowledge of the computer systems, Garman had already advised Steve Bales that the computer could be relied upon to function adequately so long as the alarms did not become continuous.<ref>[http://klabs.org/history/apollo_11_alarms/console/index.htm ''Console audio recording of Apollo 11 Lunar Landing''], klabs.org; accessed September 21, 2016.</ref> Bales, who as guidance officer had to quickly decide whether to abort the mission over these alarms, trusted Garman's judgment and informed flight director Kranz. Within seconds this decision was relayed through [[Flight controller#Spacecraft communicator (CAPCOM)|CAPCOM]] to the astronauts and the flight continued.
There were several additional alarms of the same type (both 1202 and also 1201, which indicated a vector accumulator area exhaustion), and then the crew was able to stop them from recurring by changing the landing procedure slightly to reduce the computer's tasks. Apollo 11 went on to land successfully and Garman received an award from NASA for his role in the mission. Bales later recalled, "Quite frankly, Jack, who had these things memorized said, 'that's okay', before I could even remember which group it was in.”<ref>{{cite web|url=http://www.honeysucklecreek.net/msfn_missions/Apollo_11_mission/hl_apollo11.html|title=Apollo 11|author=Lindsay, Hamish|access-date=11 July 2006}}</ref> Garman’s quick reactions and in-depth knowledge led others on his team to give him the nickname "Gar-Flash".<ref>{{cite episode|title=Part 3: The Navigation Computer|episode-link=Moon_Machines#Part_3:_The_Navigation_Computer|series=Moon Machines|airdate=June 2008|season=1|number=3}}</ref>
===IT and senior management=== After the Apollo program, Garman and center director [[Chris Kraft]] collaborated in the then-new [[Spacecraft Software Division]] where Garman worked on [[Space Shuttle]] software, including the [[Flight Computer Operating System]] (FCOS) and the high-level programming language [[HAL/S]].<ref>{{cite web|url=http://www.jsc.nasa.gov/jscfeatures/articles/000000970.html|archive-url=https://web.archive.org/web/20120216103658/http://www.jsc.nasa.gov/jscfeatures/articles/000000970.html|url-status=dead|archive-date=16 February 2012|title=JSC Features - Storytelling with Jack Garman|work=nasa.gov|access-date=22 September 2016}}</ref> From 1986 through 1988 he worked at NASA Headquarters in [[Washington, D.C.]] as director of information systems services in the Space Station Program Office. Returning to [[Johnson Space Center]] in 1988 he held various senior positions in information systems, finally serving as Chief Information Officer of Johnson Space Center from 1994 through 2000.
==Later career== In 2000, Garman left NASA and became a part of the OAO Corporation. Two years later OAO was bought by [[Lockheed Martin]] and Garman became Lockheed Martin's technical director of NASA services, in charge of technical support for the company's contractual activities with NASA.<ref>{{Cite web |last=Roberts |first=By Sam |date=2016-09-25 |title=Jack Garman, whose judgment call saved moon landing, dies at 72 |url=https://www.houstonchronicle.com/news/houston-texas/houston/article/Jack-Garman-whose-judgment-call-saved-moon-9279823.php |access-date=2026-04-20 |website=Houston Chronicle |language=en}}</ref>
==Personal life== For his service to the program, Garman was honored with numerous NASA awards, including two exceptional service medals. In 1970, Garman was part of the [[Apollo 13]] team awarded the [[Presidential Medal of Freedom]] by President [[Richard Nixon]].<ref name="obit"/>
Garman was married to the former Susan Hallmark of Los Angeles; they had two daughters.<ref name="obit"/> Garman died near [[Houston, Texas]], of [[bone marrow cancer]] on September 20, 2016, at the age of 72.<ref>{{cite news|url=https://www.nytimes.com/2016/09/25/us/jack-garman-whose-judgment-call-saved-moon-landing-dies-at-72.html|title=Jack Garman, Whose Judgment Call Saved Moon Landing, Dies at 72|first=Sam|last=Roberts|work=The New York Times |date=24 September 2016|access-date=30 January 2019|via=NYTimes.com}}</ref><ref name="obit">{{cite web|url=http://www.collectspace.com/news/news-092016a-obituary-jack-garman-apollo11.html|title=Jack Garman, NASA engineer who 'saved' Apollo 11 from alarms, dies at 72|date=September 21, 2016|access-date=September 21, 2016|author=Pearlman, Robert}}</ref>
==See also== * [[Margaret Hamilton (scientist)|Margaret Hamilton]]
==References== {{reflist}}
==External links== * [http://klabs.org/mapld05/invited/garman_bio.htm John R. Garman: Biography] * [https://web.archive.org/web/20080309202531/http://www.jsc.nasa.gov/history/oral_histories/GarmanJR/GarmanJR_Bio.pdf John R. Garman Biographical Data Sheet] * [http://klabs.org/history/apollo_11_alarms/console/index.htm Console Audio of Apollo 11 landing] * [https://web.archive.org/web/20041104030555/http://www.jsc.nasa.gov/history/oral_histories/GarmanJR/garmanjr.pdf Oral Histories]
{{DEFAULTSORT:Garman, Jack}} [[Category:1944 births]] [[Category:2016 deaths]] [[Category:NASA people]] [[Category:Apollo 11]] [[Category:Engineers from Illinois]] [[Category:Engineers from Texas]] [[Category:University of Michigan College of Engineering alumni]] [[Category:People from Oak Park, Illinois]] [[Category:Deaths from cancer in Texas]] [[Category:Place of death missing]]