Incorrect Hohmann maneuver when not at pericenter?

[astrojuanlu]

🐞 Problem

I think there is a potential problem here:

poliastro/src/poliastro/maneuver.py

Lines 100 to 101 in bc4c008

	if orbit_i.nu is not 0 * u.deg:
	orbit_i = orbit_i.propagate_to_anomaly(0 * u.deg)

poliastro/src/poliastro/maneuver.py

Line 144 in bc4c008

return cls((0 * u.s, dv_a), (t_trans, dv_b))

in that the time to get to the pericenter is not being taken into account for the maneuver, and therefore perhaps doing an apply on the initial orbit won't have the intended effect.

💡 Possible solutions

Note I didn't check whether this is an actual bug or not yet

Do not hardcode the initial maneuver to 0 * u.s and use the time to get to the pericenter.

📋 Steps to solve the problem

• Comment below about what you've started working on.
• Add, commit, push your changes
• Submit a pull request and add this in comments - Addresses #<put issue number here>
• Ask for a review in comments section of pull request
• Celebrate your contribution to this project 🎉

[jorgepiloto]

Interesting... The same happens in Bielliptic ones. Some possible solutions that came to my mind:

• We could raise ValueError("Not in pericenter...") so the user is forced to propagate before solving the maneuver.
• In case-solving internally time to pericenter, the set of impulses should be like:

{propagation: till periapsis, second: first hohmann impulse, third: second hohmann impulse}

That propagation impulse always has deltaV = 0 * u.km / u.s and time may vary between [0 and T)

[astrojuanlu]

I would rather do the latter instead of raising the error.

[astrojuanlu]

Fixed in #744.

[astrojuanlu]

I think I forgot to close this. Doing it now.