On Jan 2, 2016, at 6:49 AM, John Schilling <John.Schilling@xxxxxxxxxxxxxx>
wrote:
On 12/30/2015, Henry Spencer wrote:
My understanding -- not that I was following ALASA closely -- is that that
was the original plan, but they eventually decided that dropping the tank
gained them so little that there was no point. Mitch Burnside Clapp (who
is/was the ALASA project manager), at last spring's Space Access, described
it as "the only launcher whose stage count changed after PDR". They decided
to leave the engines where they were, partly because volume constraints
under the F-15E made it difficult to move them -- the payload volume tapers
toward the rear, and the engines can't be too close together because ALASA
uses differential throttling for control.
In any case, ALASA is grounded and probably dead. Two consecutive safety
tests of their N2O/acetylene mixed monoprop [aieee!! aieee cubed!!] went
KABOOM KABOOM a month or so ago, and that kind of spoiled the enthusiasm for
it; see <http://spacenews.com/darpa-airborne-launcher-effort-falters>.
Mitch's comment on the monoprop last spring was "there are reasons why this
is not entirely insane", but apparently it was insane enough...
You understand correctly on the engine location. That's the only place you
can put engines big enough for ALASA and not either block the landing gear
doors or have the nozzles turn into divots on the runway when the F-15E
rotates for takeoff.
