Expedition brings with it three new maps--Swampland, Runoff, and Wargames--and is being sold for $10. It's also included with the $25 Titanfall season pass.
Following Expedition, Respawn Entertainment will release two new map packs, and the developer has said it's also working on a free update that will bring new game modes.
After all that, EA and Respawn Entertainment are showing no signs of slowing down on Titanfall: the publisher and developer have said they will release new Titanfall "experiences" in the future. It looks like the space cannon that fires Titans down onto a planet's surface will be getting plenty of use in the future, then.