ISS Service Module Thruster Test Fails

I totally concur. Thanks for corroboration.

"hop" wrote
If it is truly an external cover, this sounds like something that might
be repairable with an EVA (earlier reports implied the failure was a
propellant valve, which seems like it would be a lot nastier to work
on). Or for that matter, it might be a sensor failure, or an issue that
could be worked around with different procedures (random speculation:
opening the cover in a different thermal environment or giving the
actuator more current or more time to open.)

They also note that a reboost using only one of the SM main engine is
still possible.

"Jim Oberg" wrote:
There's no indication that the SM engines are NOT available
for reboost.

Oh, right. A failed test is *no* indication that the system has
failed.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Chris Bennetts wrote:

Derek Lyons wrote:
Chris Bennetts wrote:
The backup solution is Progress.

Incorrect. Progress is the primary system - the integral thrusters
are the backups.

You're right. I guess further backups would include reboosts by shuttle,
ATV, or Soyuz, and the station could be evacuated if none of those were
available in the months before the station reentered.

I note that ATV isn't flying, and neither is Shuttle. Soyuz flies
infrequently.

Just remember that Mir was in the same situation for almost all of its
life.


Just remember - the O-rings never *completely* failed.

Just remember - even though the specs say 'no foam impingement', it
never has actually caused serious damage.

As Jim himself has said on numerous occasions, 'getting away with
something does not mean it was safe'.

Derek, those are bad comparisons. Compared to those two cases, losing
reboost engines on the station gives you much longer to respond (several
months rather than minutes/seconds), and does not lead to the loss of
the crew (short of Soyuz failing, and not being able to launch another
Soyuz or shuttle on a rescue mission).

The loss of the reboost engines is a concerning thing. The cause of the
failure needs to be identified so that any related problems can be
mitigated against. But this is *not* anything like the problems that
caused the loss of Challenger or Columbia.

The comments were a test of whether or not you are thinking - and you
failed by reacting to the emotional content rather than the
engineering or managerial content.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Jeff Findley wrote:

So can fuel on ISS be transferred to a docked Progress, or is fuel transfer
only possible from Progress to ISS?

I'm 99% sure that transfers can be made in either direction.

--Chris

It's how it failed.

"Derek Lyons" wrote in message
...
"Jim Oberg" wrote:
There's no indication that the SM engines are NOT available
for reboost.

Oh, right. A failed test is *no* indication that the system has
failed.

"Jim Oberg" wrote in message
...
It's how it failed.


Point though is still that it failed.

As for timing the door opening. That's great. What if you time it but it's
still really closed?



"Derek Lyons" wrote in message
...
"Jim Oberg" wrote:
There's no indication that the SM engines are NOT available
for reboost.

Oh, right. A failed test is *no* indication that the system has
failed.

Greg D. Moore (Strider) wrote:
As for timing the door opening. That's great. What if you time it but it's
still really closed?

Presumably there's no way the door can be viewed by any external
cameras? I guess not - I presume it's out of the reach of SSRMS, and ERA
won't be launched for a good while yet.

Would it be feasible to just try to open the door (without firing the
thruster, of course) during an EVA and having the astros take a look? I
guess not due to the potential contamination risk. Or how about trying
to open it (again without firing) while some other spacecraft is close
enough to see the door, say during a Soyuz approach or relocation
manoeuvre?

Then again, perhaps there's some easier way of solving the problem and
my questions and conjectures are totally futile...

John.

--
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"Jim Oberg" wrote:

"Derek Lyons" wrote in message
...
"Jim Oberg" wrote:
There's no indication that the SM engines are NOT available
for reboost.

Oh, right. A failed test is *no* indication that the system has
failed.

It's how it failed.


Jim - the engine failed to fire for a test, how it failed doesn't
matter a whit. Everywhere I've ever been or seen, the working
assumption is that if it can't pass testing, it can't be treated as
operational.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Chris Bennetts wrote in
:

Jeff Findley wrote:

So can fuel on ISS be transferred to a docked Progress, or is fuel
transfer only possible from Progress to ISS?

I'm 99% sure that transfers can be made in either direction.

Make that 100%. :-)


--
JRF

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check "Organization" (I am not assimilated) and
think one step ahead of IBM.

Derek Lyons wrote:
Chris Bennetts wrote:
[...]
The loss of the reboost engines is a concerning thing. The cause of the
failure needs to be identified so that any related problems can be
mitigated against. But this is *not* anything like the problems that
caused the loss of Challenger or Columbia.

The comments were a test of whether or not you are thinking - and you
failed by reacting to the emotional content rather than the
engineering or managerial content.

No, the managerial and engineering content is that you start planning
additional tests, making use of the long time you have available before
this *test failure* becomes a critical event.

You start planning, as Jim O noted, testing with Engine 1 only, and
addtitional tests to determine if the Engine 2 cover can be opened. As
a manager, you ask your engineer how long before deorbit, and you draw
a chart on the board with that time as the base bar, and along it the
usuall Gantt chart entries for each new test.

You don't conclude you're out of options until all boosting craft are
grounded or inoperable, and all chances to bang on the gizmo with a
hammer have been used up.

/dps