According to the NASA Johnson video Space to Ground: A Star to Steer By: 08/10/2018:
A tool that once helped sailors cross vast oceans for centuries is now being put to the test in space. The crew has been testing out a sextant, a device with a small telescope-like sight that can take precise measurements between pairs of stars. These were actually used in the early days of human spaceflight on programs like Gemini and Apollo. And mission planners are once again looking at how they can be used for emergency navigation needs on deep-space exploration vehicles like Orion.
I show some screenshots below.
Question: What is the nature of the sextant tests on the ISS for Orion cis-lunar emergency navigation? I'm guessing that the idea is to use measurements of the separation between a star and a position on either the Earth or the Moon, rather than between two stars. Is there a description or a report?
In real practice, in an emergency, I'm guessing that you'd probably need an ephemeris printout, pen and paper, or a small handheld computer to do useful navigation using this technique assuming that you are beyond near Earth orbit and experiencing an emergency. It would be great to read about these procedures if there's anything written about it.
- Was the Apollo sextant used (or tested) to determine position while in Earth orbit?
- What naturally occurring navigational information is available for an autonomous return of SLS's EM-1?