The Space Needle is an 8-furnace, single-thruster, 8-tile-wide Factorio spaceship design. It can be built in 20 launches.
It is an experiment in finding the fastest speed while using only one chemical plant each for fuel and oxidizer, without using any fluid storage tanks, while also being a fully functional cargo ferry (i.e., with on-board ammo generation).
When leaving Nauvis orbit, the ship will hit a peak of 173km/s while burning through the thruster's internal reservoir, then settle into a stead-state speed of 122km/s shortly before reaching the half-way point to Fulgora. That's pretty incredible for a single chem plant with no fluid tanks.
The key to this performance is exploiting the game mechanic that, given two ships with the same thrust and weight, the narrower ship will reach a higher top speed. This ship is the narrowest possible design (8 tiles wide).