ktyl
/
skein
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

doc: add todo.md

This commit is contained in:
Cat Flynn 2024-09-24 00:52:10 +01:00
parent 788b03b2c6
commit 771570468e
1 changed files with 32 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
todo.md Normal file
View File

@ -0,0 +1,32 @@
Can we determine orbits entirely from an orbital state vector?
Can we use a state vector to generate initial orbital elements?
Can we use a state vector to modify an existing orbit?
The [perifocal reference frame](https://orbital-mechanics.space/classical-orbital-elements/perifocal-frame.html) has a right-handed coordinate system where p=x,q=y and w=z.
We want to be able to represent three orbit types individually as elliptical orbits are fundamentally cyclical in a way that para/hyperbolic orbits are not.
Hyperbolic orbits more useful than parabolic since they allow us to actually leave a planet.
They need to be positioned at a unique point in time, where elliptical orbits do not.
What additional orbital element information is required to position them in time?
Orbits take place in a (non-inertial?) reference frame. How should we model these?
We need a set of 3D axes and a clock for a reference frame.
What elements of our existing implementation would change?
It should be possible to get reference frames from a particle.
Should we be constructing orbits with a reference frame?
- [x] Make C properly pause time
- [x] Make W print out the normalized Cartesian velocity
- [x] Verify that the velocity is in opposite directions on opposite sides of the orbit
- [x] Make W convert the orbital elements to cartesian
- [x] add 10% to the velocity
- [x] then convert cartesian back to kepler elements and update the orbit
Now we can update the shape of the orbit but the position of the planet is not preserved. This is probably because we are calculated mean anomaly as a function of time, instead of taking into account the planet's existing elements.
Therefore when converting from cartesian to keplerian elements, we lose the information about the true anomaly. If we conserve this information when setting the planet's position in following frames we should maintain the planet's position within its orbit.
Currently we get a planet's position by querying the map with a time parameter. Instead, we should update the map with a time parameter and then query it. This means that we can update the entire map to the same time value, and then operate on its objects in the context of a single instant. We still avoid directly storing a time value in the map, but we will have complete elements with which to orbital operations.
I think to resolve this we will have to update the particle map (particle simulation?)