The Blue Engine 4 (BE-4) is an oxygen-rich liquefied-methane-fueled staged-combustion rocket engine produced by Blue Origin. The BE-4 was developed with private and public funding. The engine has been designed to produce 2.4 meganewtons (550,000 lbf) of thrust at sea level.

Peregrine Lunar Lander flight 01, commonly referred to as Peregrine Mission One, was an unsuccessful American lunar lander mission. The lander, dubbed Peregrine, was built by Astrobotic Technology and carried payloads for the NASA Commercial Lunar Payload Services (CLPS) program. Peregrine Mission One launched on 8 January 2024, at 2:18 am EST, on the maiden flight of the Vulcan Centaur (Vulcan) rocket. The goal was to land the first U.S.-built lunar lander on the Moon since the crewed Apollo Lunar Module on Apollo 17 in 1972.