During lift - off (as per my knowledge) the Apollo 11 had accelerometers that would determine the position of the rocket. This would work great due to the earth's gravity. But how did the Command Module or rather the 1st stage know its orientation/position midway to the lunar encounter? did they use a different technology or did I get this all wrong?
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1$\begingroup$ Terms you’ll be interested include “attitude control”, and the “Apollo IMU”. Related questions: space.stackexchange.com/questions/40048/… and space.stackexchange.com/questions/40188/… $\endgroup$– fyrepenguinCommented Sep 6 at 8:06
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11$\begingroup$ Accelerometers don't need "earth's gravity" to work. See space.stackexchange.com/q/64909/6944 $\endgroup$– Organic MarbleCommented Sep 6 at 12:16
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1$\begingroup$ Thought they just used something similar to a sextant to align with the stars. astronomy.com/space-exploration/the-story-of-the-apollo-sextant $\endgroup$– Greg MillerCommented Sep 6 at 15:53
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3$\begingroup$ the question body is alright, but the title "gyroscopic position" doesn't make sense $\endgroup$– Erin AnneCommented Sep 6 at 20:09
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$\begingroup$ en.wikipedia.org/wiki/PIGA_accelerometer $\endgroup$– Phil SweetCommented Sep 7 at 16:42
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Apollo had 3 ways to know the attitude and position of the spacecraft.
Position, distance and speed were calculated based on the radio link between earth and the spacecraft (distance by time-of-flight measurement and speed by measuring doppler shift).
Additionally, there was the primary guidance, navigation, and control system PGNCS on board which used gyroscopes and accelerometers to keep track of attitude and calculating the current position. There was always a bit of uncertainty with those measurements, so they had to be corrected from time to time with information from the ground.
It was also connected to a steerable telescope where astronauts could visually point at certain stars and realign the system if necessary.
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6$\begingroup$ It would be worthwhile to mention integrating accelerometers, which tell you how much total acceleration you've undergone along an axis. $\endgroup$ Commented Sep 6 at 21:45
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3$\begingroup$ further reading: several questions about the Apollo sextant $\endgroup$– uhohCommented Sep 7 at 1:33