The POD team developed the ICESat-2 orbit with the initial
requirements of: (1) a 92°inclination orbit for coverage of polar ice
and sea ice while still producing orbit-crossings for altimeter
cross-over observations, (2) a frozen orbit to limit altitude
variation at any given latitude in order to maintain beam pattern
geometry on the surface, (3) ...
Please be aware of different uses of the phrase "space tug" I've noticed in literature and at conferences.
Meaning A is a vehicle resident in space capable of i) rendezvous and docking, ii) manoeuvering and iii) releasing a client.
Meaning B is just items ii) and iii) and thus can include spacecraft considered by some to be "just" an upper stage, e.g. ...
You might want to check out this MSc research published in 2017: "Feasibility of Reusable Continuous Thrust Spacecraft for Cargo Resupply Missions to Mars."
The author's hypothesis was that currently low-thrust engines could be used to for space tugs between the Earth and Mars to send dozens of tons to Mars and return 10 tons back to Earth (if I recall the ...
For Python and TLE propagation using SGP4 one very handy option is https://rhodesmill.org/skyfield/
As you probably already know a TLE is a strange animal. It does not really contain proper orbital elements, but instead is engineered with one purpose; to be fed into SGP4 so that that will generate reasonable position information for at least a few days ...