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This ballistic "space" ship started as a plane and was landed as a plane too. To fly as a plane horizontal speed was necessary. When the hybrid rocket engine was ignited, the ship gained vertical speed. Conservation of energy is valid for such ships too, therefore the horizontal component of speed was not changed. To avoid any waste of rocket fuel ...


4

Using Python code How do I determine the ground-track period of ... from uhoh: and Great Circle Distances in Python from Chris Webb, I wrote a program to plot the distance of the ISS ground track to a given reference point on Earth during 4 days after November 17, 2020. The minimum distance is 113.81 km, calculated every minute of 4 days. The ISS moves very ...


3

I can't answer why it takes weeks, but I found a few details on the propulsion system in: CryoSat Mission and Data Description, 2001 (Thanks, Wayback Machine!) The satellite has cold gas thrusters for orbit control. 4 thrusters with 40 mN each, to be precise. They are operated with 37 kg nitrogen gas at up to 276 bar. Raising a 700 km orbit by about 1 km ...


2

I found it in the meantime: Using the length_of function to check an arcminute length, a meridian, the equator and pole diameter: from skyfield.api import Topos, load from skyfield.functions import length_of ts = load.timescale(builtin=True) t = ts.utc(2021, 1, 1) b1 = Topos(0., 0., elevation_m=0.0) b2 = Topos(1. / 60., 0., elevation_m=0.0) print(round(...


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