Questions tagged [ranging]

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How did LADEE and LDRC measure it's distance from Lunar orbit to Earth to 1 centimeter accuracy using optical communications?

The video Donald Cornwell plenary talk: NASA's Optical Communications Program: 2015 and Beyond was presented at SPIE Photonics West 2015. It's a great talk and worth the time. LADEE had [the Laser ...
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Long delay-doppler measurements on deep space craft; couldn't optical measurements be made intermittently, mixed with contacts to other spacecraft?

In this comment below Will future deep space optical communications “ground stations” actually be in space, or on the ground? in response to a discussion about ground stations being used for tracking ...
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126 views

When they shoot lasers at the Moon for ranging, what is the shape of the beam?

Laser ranging of the Moon is usually done with a Q-switched pulsed laser fed into a big (1 or 2 meter diameter) telescope as a collimator in order to get a tight beam all the way to the Moon in hopes ...
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Parallax calculation

Given two points of observation on Earth (obs1=[lat1,lon1], obs2=[lat2,lon2]) and the apparent azimuth and altitude of a target from these two locations ...
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667 views

How do ultra-stable oscillators for spacecraft work?

Many spacecraft carry "ultra-stable oscillators" for ranging and related measurements, but I can't quickly find any info on how these actually work. Are they just very pure quartz crystals, or do they ...
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How soon after “The Eagle” landed did they first attempt to bounce a laser off the Moon? When did it first succeed?

The question When did Houston figure out where the Eagle had landed? says (in part): During Apollo 11's stay on the surface, Michael Collins was given seven different locations to look for the ...
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113 views

How to get an initial setting of the range gate for a Lunar Laser Ranging using a new Retro Reflector for the first time?

From an answer to this question They were searching by aiming their laser at the moon and looking for reflections. But the system is set to only detect photons in a very narrow range of ...