"Rocket Man" wrote on Sat, 2 Mar 2019
10:17:49 +0100:


"Jeff Findley" wrote in message
...
In article ,
says...

"JF Mezei" wrote in message
...
Saw an animation of the upcoming Fragon 2 test flight and it included
docking to the station.

Has NASA changed its policy that the first test flight nears the
station
but doesn't get t touch it?

Or have they agreed to let it do the "no touch" test flight and if that
works, then allow it to dock?

Since this is first Dragon flight docking at the modified PMA2 with
totally new guidance/navigation to it, what special steps would be
taken?

Being crewless, will this be totally automated, or will the ISS crew
use
the SpaceX equivalent to the Toru manual remote control ?

I read that the Russians are pretty nervous about Dragon2 since it
doesn't
have an independent backup computer system. If it fails the Dragon2
capsule
may beome uncontrollable and collide with the station. NASA has brushed
aside these concerns, I sure hope they know what they're doing.

From what I understand, Dragon 2 has a triply redundant computer system
so any computer hardware problem shouldn't be an issue. I'd bet the
updated computer hardware on Dragon 2 is at least somewhat based on what
was done with Dragon, which has been successful in terms of its software
used to approach and station keep near ISS so that the SSRMS can grab
it.


The difference is that Cargo Dragon is docked via a robotic arm, whilst Crew
Dragon docks via the airlock. That's a significant difference.


Yeah, I screwed that up a while back and asserted that Dragon 1 did
the auto-docking thing.


Also, the
astronauts don't have any control over Crew Dragon, it's completely
autonomous. If something goes wrong, there's nothing they can do to prevent
a catastrophe.


Which astronauts? The ones on ISS have only limited control (I
think), but I'm sure they can tell it to open away from the station
because they tested that. If it was actually manned rather than a
test the astronauts on board could fly it completely manually.


--
"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