SpaceX's Falcon 1, still looking to make its first successful orbital launch, has a USAF contract to integrate and launch a payload on a four-month schedule. By traditional space standards, this is an unheard-of schedule (or it has been since the 1950s and early 60s, when truly rapid integration and launch on a schedule now considered "impossible" was routine).
In a mission known as Jumpstart, the Falcon will carry an Air Force satellite from SpaceDev, Inc., a rideshare adapter experiment for a Malaysian organization, and two 1-kg CubeSat payloads.
As Air Force Colonel Kevin McLaughlin explained, "The Jumpstart mission is an exciting and important milestone for the ORS Office. It brings together a diverse government and industry team to demonstrate numerous ORS enablers needed to bring space power to our deployed forces."
COMMENT: When I led a study of small rapid-response launchers for Air Force Space Command back in 1996, we worked out a plan involving a 48-hour reaction time. (A quicker response did not seem worth the added expense or the trouble of conflicting with the timelines needed for NOTAMs and treaty notifications.)
The reviewer from the Air Force's Space and Missile Systems Center said we were hopelessly uninformed: a launch campaign always took many months. I messaged back to ask him if he'd ever heard of an ICBM. (I'm an old Titan II crew commander. We kept a complex, over-age liquid-fuel system and payload ready for instant launch, although I'll grant you that range safety was not exactly a priority.)
We never got an answer.