NASA Returns Sextant From Space

[Dsanduril]

https://www.nasa.gov/mission_pages/s...ws/Sextant_ISS

Given the amount of discussion that occurs here on CF about whether or not to carry a sextant, I thought others might find it interesting to read about the experiments aboard the International Space Station on using a sextant for space navigation when the systems go dark. “Why reinvent the wheel?”, sextants have been used for navigation by measuring angles for centuries. Didn’t know that the Apollo missions carried sextant aboard. Interesting that they are worth the weight penalty for getting things into space.

[SeanPatrick]

This was discussed some time ago on NavList. IIRC, the general consensus was that the whole exercise was fairly pointless and probably done just for show.


Here are some links to some of the discussions:


NavList Message Index: January, 2014 to December, 2024


NavList Message Index: January, 2014 to December, 2024


NavList Message Index: January, 2014 to December, 2024

[Adelie]

My recollection is that while it was not needed generally, the sextants provided navigational backup.

Edit: for the Apollo folks, not the ISS group.

[GordMay]

Yes, the Apollo missions carried, and used (most famously by Jim Lovell, on Apollo 8) a sextant.

The device was used repeatedly, throughout the Apollo program, across many phases of the missions, up to and including re-entry. This was not, however, your grandfathers sextant.
The Apollo sextant was used in Earth and lunar orbit, as well as while en route between Earth and the Moon. It played different roles in each of those contexts: in orbit around Earth or the Moon, the sextant could be used to compute the spacecraft’s altitude and position; whereas in transit between Earth and the Moon, it could be used to compute the spacecraft’s attitude (orientation), position, and velocity. A proper attitude during the flight to and from the Moon was critical for accurate course corrections and burns to reach the Moon and correctly insert the spacecraft into the desired lunar orbit.

The story of the Apollo sextant ➥ https://astronomy.com/news/2018/06/t...apollo-sextant

And ➥ https://www.ion.org/museum/item_view...scid=5&iid=293

[Dsanduril]

From sextant to using GPS/GNSS signals in unintended ways:

https://www.nasa.gov/feature/goddard...ms-for-artemis

I’m finding space navigation fascinating, maybe Elon will make my next cruising vessel a near earth space voyager. Wonder how you anchor it?