Jeff Findley wrote:

In article ,
says...
Unknown. That's up to SpaceX and NASA to negotiate based on NASA's
needs. Also note that Dragon isn't the cargo craft going to ISS, so
plans can always change based on unexpected events (failure of hardware
on ISS, failure of a cargo mission, and etc.).


I meant to say Dragon isn't the only cargo craft going to ISS. Orbital
ATK's Cygnus spacecraft will continue cargo missions to ISS. And it's
possible that Sierra Nevada's Dreamchaser might start making cargo
flights to ISS (if it ever finishes its test program). I'm really not
fond of horizontal landing reentry vehicles. They're unnecessarily
complex to design, build, and test.


It's not just complexity. Horizontal landers require a lot more
structure that is only used in order to get back down, so their dry
mass tends to be higher. They need both actual landing gear and
something to generate that horizontal lift (wings, a lifting body, or
both). Those things are just parasitic weight during boost, having no
purpose at all. All the machinery for retractable landing gear and
the gear itself is heavy. So is support structure for wings, etc.
Vertical landing legs are lighter and use the same machinery for
getting down as they use for going up, so it's not wasted weight
during boost.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw