GTO to GEO transfer — MIDAS 1.7.0 documentation # GTO to GEO transfer # GTO to GEO transfer# This tutorial is showing how to solve an electric orbit raising transfer from GTO (Geostationary Transfer Orbit) to GEO (Geostationary Orbit) We are going to be working with the `midas.design.sep.marta` module, let’s import it and some other `godot` modules we need. ``` from godot.core import util, num, tempo from midas.design.sep import marta util.suppressLogger() ``` We are defining the problem with an initial (fixed) epoch and a final (free) epoch to be used as initial guess for the duration of the transfer (time of flight 120 days). ``` epoch0 = tempo.Epoch("0.0 TDB") ``` We define the initial and final orbital parameters as Keplerian elements. For the free values (i.e. true anomaly) we pass `None`. The final orbit is GEO equatorial and circular, so the `AOP` and `RAAN` are not well defined, hence we pass `None` for these as well. We also define the initial mass (fixed) and final mass (free) as initial guess. ``` kep0 = [24505.9, 0.725, 27 / num.Rad, 0, 178 / num.Rad, None] mass0 = 2000.0 kep1 = [42165, 0, 0, None, None, None] ``` We use these to create boundary conditions

# What does a 6-month GTO to GEO transfer look like in practice? Tags: orbital-mechanics, geostationary, ion-thruster - Score: 4 - Views: 1094 - Answers: 1 - Answered: yes - Asked by: ymb1 (2463 rep) - Asked: 2021-03-14 - Edited: 2021-03-18 - Site: space ## Question Based on How much time does it take to circularize a GTO orbit using ion propulsion? and the launch and entry into service dates, it takes about 6 months of continuous ion propulsion to transfer a GTO to a GEO. According to a spacenews.com article, the journey was 7 months for the all-electric Eutelsat 117 West B. They have an illustration, which suggests the GTO's apogee was higher than GEO: Source: spacenews.com The post Thrust and rotation strategy to circularize a standard GTO orbit using ion propulsion? offers a theoretical approach. To a mere Kerbonaut, who only knows how to circularize an orbit by firing at apogee: when a continuous very, very, very small thrust is used in practice such as that payload (Eutelsat 117 West B) aboard the June 2016 Falcon 9 launch, how does the orbit look like as it circularizes, since the thrust is not always at apogee? Of note, I think, is the movable arms with the thrusters:

# Thrust and rotation strategy to circularize a standard GTO orbit using ion propulsion? Tags: orbital-mechanics, geostationary, hohmann-transfer, python, ion-thruster - Score: 10 - Views: 2078 - Answers: 2 - Answered: yes - Asked by: user12102 - Asked: 2016-06-07 - Edited: 2017-05-13 - Site: space ## Question The previous question How much time does it take to circularize a GTO orbit using ion propulsion? has a good, quantitative answer based on a known delta-v. But I'm wondering how would you actually aim a continuous ion thrust as you move around in a highly elliptical orbit at the beginning? Is there a way to do this without wasting a lot of propellant? Or do you use the thrust only during a fraction of the orbit (in the beginning) when near periapsis, and therefore it takes longer to accumulate the delta-v because the thruster is actually turned off a lot of the time? Here's a quick, silly calculation showing that for 0.2N and 2200kg, starting at 300km LEO, it takes about 600 days to slowly spiral out to GEO. The satellite rotates once per revolution around the earth, so I have to slow down the rotation rate a teeny tiny bit once in a while to keep them synchronized so