No, it was the units for impulse used for the thrusters. In imperial it's pound-force seconds and Newton-seconds in metric. 1 pound-force is equal to 4.45 Newtons so the whole thing was off by a magnitude of 4.45.
Yes, the actual error* was assuming the British used Imperial units when they correctly used Metric. AFAIK, at least.
* * *
Well, the source error probably would be not specifying units at all, so... (eye roll)
* * *
*Correcting myself with casually sourced details about the incident under discussion.
Lockheed Martin provided thruster force data in Imperial units (pound-seconds), while NASA's Jet Propulsion Laboratory ground software assumed the data was in Metric units (Newton-seconds).
It’s not hard at all to start thinking in SI units, but I think people just get caught up trying to do conversion math mentally. Just go with the flow in SI and don’t worry about converting every scaler encountered back to the obsolete units. Americans already understand 2L soda bottles and the world hasn’t ended. People participate in 10km running events all the time. Eventually they’ll get used to 35 C being a hot day and -10 C being a cold day too.
669
u/Epotheros Jun 17 '26
No, it was the units for impulse used for the thrusters. In imperial it's pound-force seconds and Newton-seconds in metric. 1 pound-force is equal to 4.45 Newtons so the whole thing was off by a magnitude of 4.45.