Ross Wintle

I'm watching #Artemis speed decreasing as it continues to be pulled back steadily by earth. Seems like it's just never gonna get to the moon.

But I assume, at some point, the moon starts to pull it towards it faster?

But also the moon is not directly in front of it.

Tracker: https://www.nasa.gov/specials/trackartemis/

How they calculate the trajectories now, with computers, is baffling. How they did it in the 60's I'll never understand.

#space

NASA: Artemis II

Artemis I will be the first in a series of increasingly complex missions to build a sustained human presence at the Moon for decades to come.

NASA
Nov 20, 2022 at 4:21pmWeb
Show threadRoss WintleNov 20, 2022

Oh, hang on. Orion is OUTSIDE the moon's orbit now, and the moon is actually helping to slow it down and pull it back?

The mechanics of this are mind boggling.

Show threadJohn BradburyNov 20, 2022
@ross I believe, according to my favourite science officer, that they used "stone knives and bear skins"
Show threadJohn BradburyNov 20, 2022
@ross I believe, according to my favourite science officer, that they used "stone knives and bear skins".
Show threadNafnlaus 🇮🇸 🇺🇦Nov 20, 2022

@ross Play #KerbalSpaceProgram for a while, you'll get a much better understanding of the (very counterintuitive) nature of #OrbitalDynamics :)

Oh, and how did they calculate things in the #1960s? While final trajectories were analyzed with (compute-intensive) #NBodySimulations, rough trajectories were created with "#PatchedConics", which basically sort of converts a trajectory into a #geometry problem.

Show threadFayeSNov 20, 2022
@ross watch Hidden Figures and it’s more obvious.
Show threadRoss WintleNov 20, 2022
@FayeSouthall Oh, I have. Truly incredible what those women achieved, especially given the culture in which they worked.
Show threadRoshan Kamath (रौशन् कामत्)Nov 20, 2022

@ross this book from the early 70s (which I have in my personal library) covers that aspect. I'm sure there are others. It's amazing that we can do that like you rightly said.

https://www.thriftbooks.com/w/fundamentals-of-astrodynamics_jerry-e-white_donald-d-mueller/268028/item/4355226/?gclid=Cj0KCQiAveebBhD_ARIsAFaAvrHCxpu6yrWFuVFHrCl6ycl-r3cGqJi81JE3z-j59a7bjHR41Q4xVrwaAoGwEALw_wcB#idiq=4355226&edition=2566317

Show threadaegilopsNov 20, 2022

@ross they used maths by hand, then computers - they built their own ICs and computers for the purpose, helping to kick-start the US computing industry.

https://www.embedded.com/calculating-trajectories-for-apollo-program/

https://en.wikipedia.org/wiki/Apollo_Guidance_Computer

Lots of the concepts in the AGC look amazingly recognisable!

#apollo #HistoryOfComputing

Calculating trajectories for Apollo program - Embedded.com

As part of EE Times' celebration of the 40th anniversary of Apollo 11 (launched July 16, 1969) and the first moon landing (July 20, 1969), Jack

Embedded.com