Endeavour in live.

What a shame, was really looking forward to this, anyway its better being safe than sorry

Originally posted by weedwhacker
reply to post by LaTouffe

 

Me too!!!

Alas...Scrub!!! 48-hour turn-around, at least.

APU #1 has TWO failed heaters.....sigh...

As Porky the Pig said Thats All Folks: www.youtube.com...

reply to post by FarBeyondDriven69


you're right
need a date now

reply to post by LaTouffe


Just the technical details, for those not aware: The "APU" is the auxiliary power unit....there are three, total. Launching with one not working (inop) is a no-go. But, if one failed AFTER launch, having three provides redundancy as a safety factor. (They could still manage to de-orbit and land on just one, if need be).

In this case, BOTH heaters (vital to its operational ability) have failed for some reason, on APU Unit #1.

The auxiliary power unit is a hydrazine-fueled, turbine- driven power unit that generates mechanical shaft power to drive a hydraulic pump that produces pressure for the orbiter's hydraulic system. There are three separate APUs, three hydraulic pumps and three hydraulic systems.

You can read much more, here: science.ksc.nasa.gov...

Leinbach will give an explanation for this problem LIVE appr. in 15 minutes - stay tuned.

reply to post by weedwhacker


thanks for this useful information

reply to post by LaTouffe




It is so very complicated, not only the machine, but all the parameters involved, each time to launch. Many factors to consider.

Launch scrubs all have a set minimum "turnaround time" I imagine (but, don't have the details handy) based on where they are, at any given point, within the count-down when the call to scrub is made.

So, the "48-hours" is like a default for them....a set window, where they can use the time to re-set everything needed to re-start the count-down, and meanwhile (hopefully) trouble-shoot and repair whatever was broken or inoperative.

But....the repairs may be more extensive than thought....so........delay, delay, delay. (It's much the same in the airline business, actually. But, not quite as complicated of course).

Each launch, too......has a different payload, with its unique needs and concerns...so that makes it more complex. Then, there is weather forecasts to worry about, and also the actual physical orbital mechanics, the "window of opportunity" for a launch, when the intent is to rendezvous with a moving target already on orbit, like the ISS.....so, you can see, there is a lot to consider.......

....of course, NASA has had a lot of practice!!

Just heard the announcer on NASA tv say that it looks like its probably going to be longer than a 48 hour scrub, but just how much longer is still unknown.

reply to post by weedwhacker

REAL science threads deserve more attention and applause.
Yet, they (lke this one) attract little attention, when compared to the nonsense and Bravo Sierra types of threads that are becoming far too common, of late.
Sad, isn't it?

Ain't that the truth

It really is a shame that science has taken such a back seat when compared to all the other flotsam and jetsam.

Well said weed

reply to post by weedwhacker


yes for such device it's complicated. Sure it will take a lot of time.

Originally posted by weedwhacker
reply to post by LaTouffe

 

It is so very complicated, not only the machine, but all the parameters involved, each time to launch. Many factors to consider.

Launch scrubs all have a set minimum "turnaround time" I imagine (but, don't have the details handy) based on where they are, at any given point, within the count-down when the call to scrub is made.

So, the "48-hours" is like a default for them....a set window, where they can use the time to re-set everything needed to re-start the count-down, and meanwhile (hopefully) trouble-shoot and repair whatever was broken or inoperative.

But....the repairs may be more extensive than thought....so........delay, delay, delay. (It's much the same in the airline business, actually. But, not quite as complicated of course).

Each launch, too......has a different payload, with its unique needs and concerns...so that makes it more complex. Then, there is weather forecasts to worry about, and also the actual physical orbital mechanics, the "window of opportunity" for a launch, when the intent is to rendezvous with a moving target already on orbit, like the ISS.....so, you can see, there is a lot to consider.......

....of course, NASA has had a lot of practice!!

a thing that has 270,000 moving parts built by the lowest bidder? Makes you feel good doesn't it? Rockhound, Armageddon