The instrument is the particular radar. They usually have two at each location. Each radar is essentially a linear phased array that creates multiple possible beam locations in the radar plane. They light up a beam as a satellite passes through in order to collect measurements. TLDR an instrument has multiple beams.
I'm about to wrap up my 3rd year as a one-person company (https://www.exaresearch.com) specializing in spacecraft flight dynamics and space situtational awareness (SSA). I basically do custom orbit determination things. Super fun. I spent 30+ years in the business before going out on my own. It's going great, primarily because I have a large network in a niche field.
This is fantastic. I've just started skimming through these. As an orbit determination person, this one hits home (page 207). Thou shalt not do anything that is a maneuver without coordinating/informing the OD team.
"SUBJECT: Let 's have no unscheduled water dumps on the F ''mission
During a recerit Data Selection Mission Techniques meeting we were
informed that the CSM bas some sort of automatic water dump system.
It was even rumored that it might be enabled on the F mission while
the crew is sleeping during cis-lunar flight. This memo is to inform
everyone that an unscheduled water dump can really screw up M3FN orbit
determination. Accordingly, if we have a vote, this automatic capability,
if it exits, should be inhibited and water dumps should only be performe! as scheduled by MCC-H."
Purify was a fantastic tool and I would have cheerfully paid $100K in late-90's dollars. We demoed it and the amount of memory errors it found in our legacy C and nascent C++ code stack was simultaneously depressing and exciting. We bought licenses and went to town. There was a markable product quality improvement as a result, at a time when our sales were exploding. I've never found a memory tool since that was as capable. We were running SGI IRIX boxes at the time.
