Norman,
For what it's worth, you don't really need equatorial orbit for a depot in
order to support interplanetary missions. In fact for high declination
targets like asteroids, a higher inclination orbit is actually preferable.
I did a few papers on this topic for an AAS astrodynamics conference last
year and the year before (copies available here:
https://selenianboondocks.com/wp-content/uploads/2018/02/AAS-17-696-1.pdf
and here:
https://selenianboondocks.com/wp-content/uploads/2018/09/RAAN-Agnostic_3-BurnPaperV2_AAS-18-447-1.pdf
).
If I were doing a depot for dedicated beyond LEO smallsat launch (a market
for which I have at least some data suggesting it could be a good place to
start for depots), I'd put it in an ISS inclination orbit, same plane, but
far enough ahead or behind the ISS to make NASA comfortable. At least for
the foreseeable future, ISS orbit is likely going to be a place where
crewed space facilities exist, and most of our ways of getting crew/cargo
to such facilities provides opportunities for taking advantage of surplus
propellant. That wouldn't necessarily be enough propellant to be
interesting for say sending a crewed mission to the Moon, but it's likely
more than plenty to enable some really interesting things in dedicated
beyond-LEO smallsat launch. Right now most of the options for sending
smallsats to MEO, GEO, lunar vicinity, or deep space all suck in one way or
another, and at least the numbers I've run suggest you could close a
business case off of a "micro depot" for smallsat launcher upper stages in
LEO. It's not our core focus at Altius (It's a "second horizon goal"), but
we're actively working on trying to retire technical risks to make it
happen. Even getting paid by NASA on some of them.
~Jon
On Sun, Aug 25, 2019 at 4:53 PM Norman Yarvin <yarvin@xxxxxxxxxxxx> wrote:
As regards fuel depots in LEO, what orbit do people conceive them as
being in? Equatorial orbit, so that they can service launches heading
to GEO and beyond? Something like the Space Shuttle's usual orbit, so
that launches from Florida can reach them without a plane change? Or
what?
