The RS-25 engines in this simulation are the same engines flying RIGHT NOW on SLS for Artemis. The code that evaluated whether the Shuttle concept would work - still gets the math right for hardware heading to the Moon.
Liftoff, gravity turn, SRB separation at 50 km, MECO at 7,803 m/s. Orbital coast at 109 km. Every parameter within 5-15% of real STS data. All computed by original 1970 code — not a single formula changed.
T+0.0. ALT 10. VEL 0. GAM 90.0.
Vertical launch. Cape Canaveral, Pad 39.
Computer: not a UNIVAC 1100.
Built a scipy optimizer that runs the 1970 Fortran as a black box — 429 iterations, matching outputs against Shuttle data from Wikipedia and NASA fact sheets. SSSP-in-the-loop. Five minutes to calibrate a 50-year-old program.
Written for a UNIVAC 1100, five years before Congress approved the Shuttle. The test data? Dot-matrix printer scans from 1970. Every page: "REPRODUCIBILITY OF THE ORIGINAL PAGE IS POOR." The archive maintainer gave up in 2009.
10 fixes to compile on a MacBook. But the real problem: 300 unknown coefficients, no readable docs. The solution? Wikipedia as ground truth — real Shuttle specs, publicly available.
How was your weekend? I spent mine launching the Space Shuttle. With NASA code from 1970 that nobody could run for 50 years.