Pointing model from other spacecraft data

[benmontet]

Following on from a conversation with Adina: The TESS team now publishes their quaternion data. I wonder if we can use that to make a better (more accurate, equally accurate but more stable, faster to produce, or otherwise just alternative) pointing model

[benmontet]

I'm going to hack on this one day at #tessninja. I talked briefly about this with Geert/Christina at AAS and got some ideas!