Rocket trajectories have been planned using model-based optimization of command sequences since computers existed, essentially since the early 1960s.

Judge as of 2024-03-08 using histories of astrodynamics and optimal control. True: sources show that by around the early 1960s, rocket and spacecraft trajectories were planned with computers by optimizing command or control sequences against a dynamical model (e.g. numerical optimal control, the Kelley–Bryson gradient methods, Apollo-era trajectory optimization), and this has continued since. Mostly true: the practice is confirmed but became established somewhat earlier or later (within roughly five years of the early 1960s), or 'since computers have been around' is a loose stretch for a practice that began in the late 1950s or early 1960s. Mixed: computer-based model optimization of trajectories existed then but was a minor method, and was not how trajectories were generally planned until much later. Mostly false: computerized model-based trajectory optimization became standard only well after the 1960s (e.g. the 1970s or later). False: the evidence shows trajectories were not planned this way in that period at all.

Set before the research began.

1. E1 Trajectory optimization - Wikipedia Wikipedia · 26 June 2005

   “In the 1950s, the digital computer started to make trajectory optimization practical for solving real-world problems.”

2. E2 [PDF] Spacand~-Amnistrtio NASA Manned Spacecraft Center (MSC Internal Note MSC-IN-66-ED-43, by J. M. Lewallen) · June 1966

   “numerical computation schemes were lacking. One of the first”

3. E3 Gradient Theory of Optimal Flight Paths ARS Journal (AIAA), by Henry J. Kelley, Grumman Aircraft Engineering Corp. (hosted copy at perceptrondemo.com) · October 1960

   “For the purpose of exploring the computational aspect of”

4. E4 Gradient Theory of Optimal Flight Paths ARS Journal (AIAA), by Henry J. Kelley, Grumman Aircraft Engineering Corp. (hosted copy at perceptrondemo.com) · October 1960

   “ments have employed almost exclusively the classical "in”

E1 (Wikipedia's history of trajectory optimization) says that in the 1950s the digital computer began to make trajectory optimization practical for real-world problems. That puts the start of computer-based, model-based trajectory planning around the late 1950s to early 1960s. E3 and E4 are fragments of Kelley's 1960 paper "Gradient Theory of Optimal Flight Paths". The paper's title and date place gradient-based computational methods for flight-path optimization in that period, though the fragments themselves give no detail. The evidence supports the timing in general terms, but it is thin on whether this was the standard way trajectories were planned and on its continued use since, so the verdict is mostly true rather than true.