Can 2 Shuttles dock to ISS at once?

Isn't PMA-3 on the other side of Node 1 from the Quest airlock?



"Jorge R. Frank" wrote in message ...
(Explorer8939) wrote in
om:

To put this positively, if Node 2 is available and Node 3 is not, two
shuttles could dock at ISS at the same time.

I don't think so. The shuttle that docks to PMA-3 would still collide with
Quest. Node 3 is required to provide clearance between the shuttle and
Quest.

(Explorer8939) wrote in
om:

"Jorge R. Frank" wrote in message
...
(Explorer8939) wrote in
om:

To put this positively, if Node 2 is available and Node 3 is not,
two shuttles could dock at ISS at the same time.

I don't think so. The shuttle that docks to PMA-3 would still collide
with Quest. Node 3 is required to provide clearance between the
shuttle and Quest.

Isn't PMA-3 on the other side of Node 1 from the Quest airlock?

Correct; it's currently on the Node 1 port CBM, while Quest is on Node 1
starboard. However, in that location, a shuttle cannot dock due to
collision with the P1 center radiator during approach, and the Ku band
antenna during docking. Clearances with the P1 truss and FGB port solar
array are also extremely tight. Plume impingement from the forward RCS on
the P6 4B solar array would be very high and would be difficult to mitigate
("feathering" the solar array edge-on to the approaching shuttle would
greatly reduce clearance).

I assumed, therefore, that PMA-3 would be relocated to the only other Node
1 CBM, on the nadir side. But on that CBM, a nose-forward docking would
result in collision between the shuttle tail and the Russian segment, while
a tail-forward docking would result in collision between the shuttle tail
and the other shuttle docked to PMA-2. So the only remaining "clockings"
are nose-port and nose-starboard, both of which have clearance problems
with Quest. Nose-port might be possible, but just barely - there's not a
lot of clearance between the Quest external tanks and the payload bay
sills.

--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

"Jorge R. Frank" wrote in message
...
Nose-port might be possible, but just barely - there's not a
lot of clearance between the Quest external tanks and the payload bay
sills.

IIRC, there are 11 mounting locations for HP gas tanks on the Equipment
Lock, mounted evenly around the circumference. Would it be possible to move
the offending tanks to other locations? It would require two EVAs, but it
could make the difference. One EVA would be needed anyway to connect the
PMA-3 cables, adding another shouldn't make too much of a difference.

--Chris

"Chris Bennetts" wrote in
:


"Jorge R. Frank" wrote in message
...
Nose-port might be possible, but just barely - there's not a
lot of clearance between the Quest external tanks and the payload bay
sills.

IIRC, there are 11 mounting locations for HP gas tanks on the
Equipment Lock, mounted evenly around the circumference. Would it be
possible to move the offending tanks to other locations? It would
require two EVAs, but it could make the difference. One EVA would be
needed anyway to connect the PMA-3 cables, adding another shouldn't
make too much of a difference.

Hmm, hadn't thought of that. Yes, if you could move all three HP tanks from
the nadir side of Quest, clearances would be comparable to what they were
on 4A/5A. Seems risky to me to do it all with one EVA; if something goes
wrong you can't repress afterwards.

--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

On 27 Oct 2003 14:54:32 GMT, "Jorge R. Frank"
wrote:

Hmm, hadn't thought of that. Yes, if you could move all three HP tanks from
the nadir side of Quest, clearances would be comparable to what they were
on 4A/5A. Seems risky to me to do it all with one EVA; if something goes
wrong you can't repress afterwards.

Stage the EVA from Piers?

Brian

Brian Thorn wrote in
:

On 27 Oct 2003 14:54:32 GMT, "Jorge R. Frank"
wrote:

Hmm, hadn't thought of that. Yes, if you could move all three HP tanks
from the nadir side of Quest, clearances would be comparable to what
they were on 4A/5A. Seems risky to me to do it all with one EVA; if
something goes wrong you can't repress afterwards.

Stage the EVA from Piers?

Good idea.


--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

In article , "Michael R.
Grabois ... change $ to \"s\"" says...
On 26 Oct 2003 18:03:38 GMT, (Hallerb) wrote:
No. There's no place to put the secondary docking mechanism (PMA-3) that
would allow positive clearance. For "safe haven", the first (damaged)
shuttle would be undocked unmanned, and deorbited destructively, prior to
the arrival of the second.
What about on the z-axis? Wasn't that where the shuttle docked when they added
the Lab and relocated PMA2?
Oh sure lets just throw away a multi billion dollar irreplaceable asset........

This may be the first time I've agreed with Hallerb. It might be worth
the effort to equip the ISS so that it can handle a damaged Shuttle and
a rescue Shuttle. Insurance isn't cheap unless it is needed...

A free flying Shuttle has a limited lifetime (2 to four weeks?). What is
the lifetime of a Shuttle docked at ISS?


And nothing is irreplacable - Endeavour replaced Challenger, for one.

The lobby of the NASM has the Wright Flyer, (Apollo 11's) Columbia, an
X-15, the X-1, and a few lesser artifacts. How would you replace them?
--
Kevin Willoughby oSpam

Imagine that, a FROG ON-OFF switch, hardly the work
for test pilots. -- Mike Collins

Kevin Willoughby wrote in
:

In article , "Michael R.
Grabois ... change $ to \"s\"" says...
On 26 Oct 2003 18:03:38 GMT, (Hallerb) wrote:
No. There's no place to put the secondary docking mechanism (PMA-3)
that would allow positive clearance. For "safe haven", the first
(damaged) shuttle would be undocked unmanned, and deorbited
destructively, prior to the arrival of the second.
What about on the z-axis? Wasn't that where the shuttle docked when
they added the Lab and relocated PMA2?
Oh sure lets just throw away a multi billion dollar irreplaceable
asset........

This may be the first time I've agreed with Hallerb. It might be worth
the effort to equip the ISS so that it can handle a damaged Shuttle
and a rescue Shuttle. Insurance isn't cheap unless it is needed...

ISS will have that capability anyway once Nodes 2 and 3 are there. So the
question becomes, how much priority (read: $$$) are you willing to give in
order to accelerate this capability, over the ones ISS was ostensibly built
for? Bear in mind that the truss/solar arrays would be required anyway in
order to power an extended-stay orbiter, and additional life-support to
support a stranded shuttle crew for long periods.

To put it more bluntly, if you let ISS assembly run its course, you will
get what you want anyway. If you rearrange ISS assembly to give priority to
its ability to host a stranded shuttle and a rescue shuttle, you will get a
station capable of doing that - and probably little else - while spending
more money for the privilege.

Personally, I don't think this would be a smart thing to do.

A free flying Shuttle has a limited lifetime (2 to four weeks?). What
is the lifetime of a Shuttle docked at ISS?

Also 2-4 weeks, at least until a means is implemented to transfer ISS power
to the shuttle, allowing the fuel cells to be shut down and the cryo to be
preserved.


--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

Jorge R. Frank wrote:

"Chris Bennetts" wrote in
:

IIRC, there are 11 mounting locations for HP gas tanks on the
Equipment Lock, mounted evenly around the circumference. Would it be
possible to move the offending tanks to other locations? It would
require two EVAs, but it could make the difference. One EVA would be
needed anyway to connect the PMA-3 cables, adding another shouldn't
make too much of a difference.

Hmm, hadn't thought of that. Yes, if you could move all three HP tanks
from the nadir side of Quest, clearances would be comparable to what they
were on 4A/5A. Seems risky to me to do it all with one EVA; if something
goes wrong you can't repress afterwards.

That's precisely why I suggested two EVAs ;-). The first would move one O2
and one N2 tank, the second would move the other two (if needed).

--Chris

"Jorge R. Frank" wrote:
possible due to collision with the FGB. A nose-out-of-plane docking isn't
possible due to collision with the Quest airlock.

Would there be a collision even if the nose was pointed towards quest with the
tail where PMA3 currently is ?

to PMA-3 on Node 3, provided you "clock" PMA-3 for a nose-out-of-plane
docking.

Can the CBM be "clocked" ? Doesn't it have to be berthed in one specific
orientation so that connectors are aligned ? Can the PMA actually be clocked
within itself keeping the CBM orientation the same ?