from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An airbreathing aircraft engine
Sorry, no etymologies found.
No development funds (about $3B today, called Constellation) nor space systems R&D funds (about $500M today, called advanced capabilities) would otherwise be available to do airbreather work.
To - jefftracey - your mention of the airbreather depends on this interim solution resulting in a recurring yearly production and operations cost that does not consume the whole human space flight budget minus ISS.