Changes in the ESTCube-1 Orbital Elements to Date

  ESTCube-1 has has been in orbit for a little over three weeks now. It has already downloaded a few images using the onboard camera. The orbit has decayed slightly since the cubesat was placed in orbit as can be seen from the plots of the orbital elements obtained from the Space-Track TLEs. The horizontal axis is the day of the year. The inclination and ascending node specify the plane of the satellites orbit. The eccentricity, e, and the argument of perigee give the shape and orientation of the orbit. And the period, T, and the semimajor axis, a, which are related specify the size of the orbital ellipse. There is still a trace amount of atmosphere left at the satellite's altitude which causes it to slowy decay. Torques caused by gravitation due to the shape of the Earth, the Moon and the Sun cause the satellite to slowly precess changing the ascending node, alters the eccentricity and shifts the argument of perigee.