# Two line element set

I was wondering where I could find the TLE of a satellite ( I am looking for CASSIOPE). I went into this link - https://www.n2yo.com/satellite/?s=39265 but it has only got the most recent updated TLE. I would like to have the TLE of the past few days of December and searched a lot for the same but in vain. Don't they store the TLE history just like IERS stores the earth orientation parameters along with other quantities on their website?

• @MahithM The exact definition they use to calculate the sub-satellite point is uncertain since there are three different definitions of "up" from a given point on the Earth (1, 2), but it's probably the lat/lon of the sub-satellite point on the WGS84 reference sphere. If you use Python then Skyfield works nicely to process TLEs and it also has a .subpoint() method. – uhoh Dec 8 '19 at 23:59