X37 - some speculation
I'm pretty pleased about the story about the X37B in space.com. It's funny how USAF and DARPA seem to be playing tortoise to NASAs hare. While the US military may not be the most efficient organization either, at least they seem have a good handle on what 'operational' means and the importance of having a well thought out plan for maintaining and running a system when it gets past the development stage, and how important it is to design a system with operational requirements in mind. The X37B is, of course, an experimental platform but it is interesting to speculate on what it might develop into in conjunction with a suitable heavy lift launcher.
I assume that the planned tests will involve integrating the X37B into an EELV as purely a payload, ie the current 1st and 2nd stages of the launch vehicle will be used. This will put a small winged return vehicle into LEO. It is interesting to compare the possible capabilities of a hypothetical, operational follow up to this system with the needs of USAF in space.
As I understand the USAF would like to have the following:
-ability to protect/replace assets in space,
-rapid and repeated delivery of munitions anywhere, anytime,
A followup system to the X37 could possibly have the following capability:
-rapid launch to orbit via heavy lift including possible recovery of the first stage if SpaceX are eventually successful with that,
-rapid turnaround between flights if the turnaround time between heavy lift launches can be reduced,
-ability to insert an object into orbit and return to a designated landing site,
-(maybe) launch to a suborbital trajectory over a target location, followed by powered return to CONUS.
-ability to loiter in orbit, with scope for limited orbit changes,
-ability to drop a payload during some sections of its non-orbital flight path.
-Whether you think this limitation is a good or bad thing depends on your point of view, but I can't see this hypothetical system becoming a 'space weapon' capable of dropping munitions from orbit simply due to the impracticability of having to decelerate the payload from orbital velocity, and only being over the target every 90 minutes or so. (although I suppose such a system might solve a need to avoid overflights of aircraft or missiles of other non-participating nations)
-The second stage will be disposable for any standard launch system in the forseeable future.
-In the event of a full fledged attack on space borne assets, it would be vulnerable to orbital debris.
The best part is that a successful operational system will be a good demonstrator for a commercial reusable orbital stage so I'm hoping that something practical comes out of this program. Who knows if one day we might be seeing routine launches of winged orbiters atop VTVL launchers.