ISS Service Module Thruster Test Fails

"snidely" wrote:

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.

Certainly thats one view. But my point is that the view that Jim is
espousing is a dangerous one - and one totally unexpected from him.

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.

But what you don't do is say "oh, a system has failed, business as
usual mates!". That gets people killed.

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.

Did I say that they were out of options? No, I did not.

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

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

(Derek Lyons) wrote:

:"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
perational.

I'm with Derek on this one. The lead for the project needs to be
taken aside and told in no uncertain terms, "Root cause analysis - get
some! Then come back to me and describe EXACTLY what happened and
why."

--
"Rule Number One for Slayers - Don't die."
-- Buffy, the Vampire Slayer

"Jorge R. Frank" wrote in message
...
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%. :-)

So even if both of the engines on the SM fail completely and cannot be
revived, you can still transfer fuel from ISS to a docked Progress which can
burn it's engines for reboost.

How about the ATV? The quick search I did says "The ATV uses up to 4.7
tonnes of propellant to raise the ISS altitude which naturally decreases
with the residual atmospheric drag.". It's also able to "carry 9 tonnes of
scientific equipment, general supplies, water, oxygen and propellant".
What's not clear to me is whether or not it's own engines use the same tanks
which would be used to transfer propellant to (and from?) ISS.

Jeff
--
Remove icky phrase from email address to get a valid address.

Jeff Findley wrote:
How about the ATV? The quick search I did says "The ATV uses up to 4.7
tonnes of propellant to raise the ISS altitude which naturally decreases
with the residual atmospheric drag.". It's also able to "carry 9 tonnes of
scientific equipment, general supplies, water, oxygen and propellant".
What's not clear to me is whether or not it's own engines use the same tanks
which would be used to transfer propellant to (and from?) ISS.

My memory is that ATV can supply propellant to ISS, but it's own
thrusters use N204/MMH, while ISS/Soyuz/Progress use N204/UDMH

http://www.novosti-kosmonavtiki.ru/content/news.shtml (in Russian)
According to Solovyev the cover did not open fully because it was stuck
against the inter-ship comms antenna which was recently installed there
to support ATV docking in 2008. At present there are no plans to do
anything about it.

Derek Lyons wrote:
[...]
But what you don't do is say "oh, a system has failed, business as
usual mates!". That gets people killed.

Especially if it is a system that is expected to work. But there is a
sense that this was

a) a system that was expected to not work at all
b) a system that was being tried just to see whether it was
rescucitable
c) the test failed, but it wasn't a surprise
d) the test went better than expected, with a chance that rescucitation
might still be possible.

I could be wrong about a) and b), or the a) and b) part of the story
may be back-fill to cover asses. In which case, said anatomy should be
publicly stripped and paddled to discourage such covering, and the
contigency planning should be well underway.

/dps

"hop" wrote in message
ups.com...
[According to a TsUP
statement to Russian media today, the test run on 4/20 failed when an
external antenna, intended for comm with the European ATV (Automated
Transfer Vehicle) "Jules Verne", blocked the thermal (sun) cover of one
of the engines from opening fully.]"

If that is the whole story, it sound like pretty poor engineering.
OTOH, it may be simple enough to fix on EVA.

No doubt. This is the sort of thing that you can simulate on a computer.
My company makes, among other things, motion software that will detect just
this sort of problem. And I know we aren't the only ones, since there is a
bit of competition from other CAD/CAM/CAE/PDM software venders.

At the very least, the Russians could have installed the antenna on a
mock-up SM to check for clearance issues. Of course, I'm assuming that they
built an SM mock-up for ground testing purposes. When NASA was running the
Skylab program, I believe there was not only a flight backup, but a (nearly)
fully functional ground based version for testing purposes. These sorts of
things come in handy when problems develop in orbit and you need to test a
fix and/or procedures on the ground.

Jeff
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Remove icky phrase from email address to get a valid address.