The reference architecture names the first six Mars ships for convenience. We only know the planned name for one, “Heart of Gold.” The others are placeholders (for now). So you don’t have to dig through multiple blog posts, here’s the summary version.
Constellation—a Mars Colonial Cargo Ship (MCCS). A MCCS is a ship with life support capability, but for fewer passengers and more cargo than the full 100 passenger version, a.k.a. the Mars Colonial Transport. This ship will be sent unmanned in the first launch window. See Day 8.
Finity’s End—unmanned cargo ship, a.k.a. “Mars Freighter (MFR).” This ship will be sent during first launch window. See Day 8.
Nostromo—a purpose-built refinery ship, containing twin integrated ISRU propellant plants and cargo specifically associated with powering them. It will be sent during the second launch window and remain on Mars indefinitely. See Day 7.
Heart of Gold—a MCCS, this will be the first manned ship to land on Mars. It will be sent during the second launch window. See Day 7.
Serenity—a MFR, carrying additional solar panels to power Nostromo’s ISRU power plants. It will be sent during the second launch window. See Day 17.
Godspeed—a MCCS, sent during the third launch window. See Day 10.
Phoenix—a MFR, sent during the third launch window. See Day 10.
Deepwater Pioneer--a purpose-built drillship, containing an integrated water-well drilling rig capable of reaching 1 km in depth. Not part of the baseline mission architecture, but if possible, it would be desirable to send this during the second launch window. See Day 22.