The Lucy Team is using Hubble to conduct a preliminary search for small, distant satellites around the Lucy targets.
This is a photograph of the binary trojan asteroid pair Patroclus and Menoetius. Patroclus, the slightly larger member of the pair, is in the lower left. The green circle marks the Szebehely radius - the outer-most region where stable satellite orbits could exist. With these deep exposures we can see objects as small as 2 km in diameter. The diffraction spikes and small blobs are all part of the normal image pattern in Hubble. No small satellites are evident. This is an average of six images of the Patroclus-Menoetius binary taken on February 13, 2018.
This is a composite image of HST images of the Leucus, and the green circle again shows the Szebehely sphere at the time of the observations (June 2016). We would detect objects as small as 3 km (with the same albedo as Leucus). In the summer we will get two separate visits so we can subtract out the central source and improve our sensitivity in close.
We will get longer observations (about 10 time longer) of all the Lucy targets with HST summer of 2018.