The New Horizons spacecraft will be making it's approach toward one of the most distant known objects in our solar system. That object, Ultima Thule (aka MU69), is estimated to be about 20 to 30km across. Right now it's nothing more than a couple pixels wide in the probe's optical sensors, but tomorrow the probe will beam back spectacular images much like it did with Pluto four years ago. New Horizons will approach Ultima Thule a bit after 0530 UTC, but it will take over 10 hours for the data to reach us.
Project homepage: New Horizons: Beyond Pluto
Coverage schedule: New Horizons : Where to Watch
Project homepage: New Horizons: Beyond Pluto
Coverage schedule: New Horizons : Where to Watch