8

Vehicles in space need propellant for attitude maintenance. The vehicle is essentially dead when the propellant runs out. Propellant depletion is the end goal of a good spacecraft designer. All of the other reasons that follow represent situations that preferably should not happen. But they do happen, at least to some space vehicles. Vehicles in space need ...


6

The Multi-Mission Radioisotope Thermoelectric Generators (MMRTG) used by NASA are probably unfeasible for the purposes you are thinking of, although they are highly useful for space exploration. Multiple spacecraft have used these, including both Voyager 1 and Voyager 2, New Horizons, Curiosity, and the new Perseverance. This is due to their ability to ...


3

Skyfield, like most other tools that claim the ability to process TLE data, depends on a bunch of people's educated but aged guesses about what SGP4 might have been doing some time ago, rather than giving access to what SGP4 actually does right now. This made sense for a long time because there was no other way for most people to get hold of SGP4, but ...


3

If you want to understand how GPS works, a good first step would be to learn how LORAN worked. https://en.wikipedia.org/wiki/Loran-C In a nutshell, pairs of transmitting stations would send out synchronized radio signals, and by measuring the difference between the time of arrival of the signals from the two towers, a ship's navigator could know that they ...


3

That is a very simple geometric problem. Imagine a globe on your desk and two table tennis balls. You hold one ball at one side of the globe and the other ball on exactly the opposite side of the globe. You notice that these balls can't 'see' each other, no matter how large or small the distance between the balls and the globe is. Now imagine both balls in ...


2

The core idea is that each measurement you can make allows you to compute a curved surface on which the receiver must be located. Assemble multiple surfaces from different measurements, and look for the one point where all those surfaces intersect. Wherever that intersection is, your receiver must be at that point. There is an awful lot more to it than ...


2

The answer given before seems to work great, I am just here to give a different answer if you're more interested in learning about the software that goes into numerically propagation trajectories and 3D plotting The general procedure to go about solving this problem would be: Read TLE. It will give you inclination, RAAN, eccentricity, argument of periapsis, ...


2

Supplemental answer with additional background: Arthur C. Clarke explains it in their 1945 article Extra-Terrestrial Relays; Can Rocket Stations give World-wide Ratio Coverage? in Wireless World's October 1945 edition. (text version) A screen shot of a bit of the page from the link above is shown below. As far as I can tell Clarke doesn't spell out exactly ...


1

...so that I can see what is happening between published TLEs. This is a great reason to want such a feature; watching the evolution of orbital elements over time can provide some intuitive insight as to what's going on. (examples: 1, 2). It does not immediately tell you where the spacecraft is at any given point nor how fast it's going (that's what state ...


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