User:Art Mervyn/sandbox

My sandbox! Art Mervyn (talk) 19:58, 14 April 2024 (UTC)

The Voyager flight computers were/are programmed in assembly language. The original ground system was largely programmed in Univac FORTRAN V, a common and not noteworthy practice.

Art Mervyn (talk) 19:58, 14 April 2024 (UTC)

I deleted from the "Science and engineering" section the paragraph that begins: "Software for NASA probes Voyager 1 and Voyager 2 was originally written in FORTRAN 5 ..." The seeming implication of this paragraph was that the software running on the spacecraft was written in Fortran.

The Voyager spacecraft were NOT programmed in FORTRAN 5 (an "Obsolete variant" running on Data General minicomputers). The source of this claim, the cited 2013 WIRED article, was actually referring to ground system "control and analysis" software.

The article was based on an interview with Suzanne Dodd, a Voyager sequence engineer in the 1980s who returned to Voyager in 2010 as its program manager. Sequences were developed in the 1980s using tools written in UNIVAC FORTRAN V (another "Obsolete variant") running on UNIVAC 1100-series mainframes at JPL. My guess is that the interview with Dodd was by phone and she said "Fortran Five" for FORTRAN V.

Fortran was commonly used in spacecraft ground systems and its use on the Voyager project is not noteworthy. The evolution to Fortran 77 and C was also typical, as mainframes were replaced by minicomputers and then PCs or Unix workstations.

The flight software running on the Voyagers' onboard computers was and is written in assembly language (2 or 3 languages for the three sets of computers); see this 2016 paper, "Voyager Interstellar Mission" (PDF: https://arc.aiaa.org/doi/pdf/10.2514/6.2016-2415), p. 6, by Sun Kang Matsumoto, a long-time and current Voyager flight software engineer.

Matsumoto's paper, p. 4, also discusses the original use of Univac mainframes for the ground software. Univac's FORTRAN 5 became available in the mid-1960s, so it would have been the standard Univac compiler for Voyager in the 1970s.

(For more sources and a more detailed examination of the Fortran 5 claim, see my personal web page, http://www.geonius.com/writing/other/voyager.html .)

Art Mervyn (talk) 19:58, 14 April 2024 (UTC)