Space Shuttle getting ready to launch in an hour:

[originalpckelly]

http://www.nasa.gov/multimedia/nasatv/index.html

[bbinacan]

1. Thanks for the heads up

I love a night launch.

[lapfog_1]

4. Might be the last one for a very long time. - n/t

[bbinacan]

5. Yes and that's a shame. n/t

[lapfog_1]

7. Hey, the NASA spokesperson just covered my teams

primary contribution to safe Shuttle flights. Namely the throttle down at Maximum Atmospheric Pressure.
A procedure recommended by my team at the Numerical Aerodynamic Simulation Facility at NASA Ames Research
Center some 20 years ago now (just before the return to flight after the Challenger disaster).

[bbinacan]

11. So cool n/t

[originalpckelly]

8. What?

The last one is not scheduled until next year. Although, they've had a LH2 leak and that's part of the fuel. Let's hope you're wrong.

[lapfog_1]

10. The last scheduled NIGHT launch.

All of the remaining in the schedule are daytime launches.

Of course, the scheduling could change.

[tangent90]

18. Oh! twilight

:D

[tangent90]

17. Do you know something we (and NASA) doesn't?

??

[lapfog_1]

23. This is the last scheduled night launch of the Shuttle fleet. - n/t

[tangent90]

25. ah okay

...

[BuyingThyme]

2. Thanks. It's sure boring today.

I hope it gets covered.

[itsrobert]

3. 2009: Where's it going? to Mars? Jupiter? The colonies on Europa?

Let me know if they come in contact with intelligent life.

[alfredo]

13. It's going to New Jersey to search for intelligent life, or a good cheese pizza.

[RoyGBiv]

6. Help me out here ...

I am almost totally ignorant of space shuttle launch protocol.

What are "planned holds" to the countdown? I understand they involve systems/security checks and such. What I don't understand is why, for example, we have a countdown that is no held at T-9:00 for a planned hold of 45 minutes.

Why is that 45 minutes not added to the countdown itself?

The whole concept of the countdown as I understood it as a child with the televised broadcasts of Apollo missions is completely blown by this ... not that my perceptions are important, just that it confuses me, and I'd rather be informed.

[Rosco T.]

9. The put in the 'holds' -

so they can check on thing as you said, it's a 'hold' in-case they need to fix something. If you just put in 45 minutes, then what if it takes 70 minutes to fix?

[RoyGBiv]

14. Here's my assumption ...

And I could be totally wrong on this, so understand I'm granting that up front ... not arguing, just trying to get my mind to wrap around this.

My assumption is they allot the 45 (or however long the particular hold is) to account for problems that arise during various systems checks. At the end of 45 minutes, if everything is a go, the hold is released, and the main countdown continues. However, if at the end of that hold everything is not okay, the hold is extended.

If that is accurate, why are the 45 minutes not included in the countdown, during which they do all the stuff they would normally do during a "hold." The countdown itself is, if I'm not mistaken, already essentially a checklist. Do this thing at T-30, this thing at T-20, and so forth. Why can't the "hold" period be a part of the already existing checklist, and then, if something is amiss at the end of that period on the checklist, call for a hold to the countdown to work it out?

As a practical matter, we already have 2 countdowns anyway, one the T minus ... of song and story and one a clock that includes all the planned holds.

I assume there is a reason for this I'm just not understanding. I'm clearly not a rocket-scientist. :)

[Tejas]

16. Very good question (answer is here)

http://www.nasa.gov/mission_pages/shuttle/news/124_milestones.html

This is a different mission but as you can see they explain what the purpose the "holds" are.



For example, and to answer your particular question, scroll down the above webpage and you'll see that the 45min built-in hold at T-9min is to poll amongst everyone to see if they're in agreement that everything is still good to go.

ie: Launch director, Mission Management Team and NASA test director conduct final polls for "go/no go" to launch.



interesting stuff!

[RoyGBiv]

19. Aha!

So, from my reading through what all occurs during a hold, I gather that a "hold" period is distinguished from the regular countdown in that the regular checklist, borrowing my term from my other post, is suspended while, for all intents and purposes, people talk to each other about what all is going on. The actual process of following the launch sequence checklist is thus suspended for these minutes or hours while everyone takes stock of what's happening.

It comes across as sort of a pressure value. Even though there's a scheduled amount of time for the hold, because of the countdown clock being stopped, automated sequences don't initiate, and people have less pressure to keep the countdown running, which, IIRC, is one of the things that was involved in the Challenger disaster.

If all that is somewhere in the ballpark, I understand now. Thanks.

[Tejas]

22. Sounds right to me

There are dozens of teams doing hundreds of checks, including camera operators scouring every square inch of that magnificent work of art looking for anything out've place etc. Those in control probably take everyone's input and digests it and then decide on continuing.

Good view of the launch pad on the OP's link at the moment.

[Elidor]

12. Countdown

By Rush

http://www.youtube.com/watch?v=KFFVY97rJ5E

[Motown_Johnny]

15. delete... linked to the wrong post

[Tejas]

20. T9 + 16hold - bat perched on the external fuel tank

Constraints List has been cleared and Management Team says "go", might be a good idea to get outa Dodge while it can.

[Not Me]

21. I get to see it lift from my front porch

We usually watch the ignition on NASA tv then run out the front door to see it clear the trees and head into orbit.

[RoyGBiv]

26. Oh, I'm jealous ...

I was visiting a friend who lives in Melbourne a few years back and was able to see a night rocket launch, which was cool all by itself, but I've always wanted to see the shuttle.

Guess I'll just stick to the broadcast.

Enjoy the view. :)

[csziggy]

39. When I was a kid, we could do the same for the Apollo rockets

Just about the time the TV cameras could not longer really see the rockets, we could run out and see them over the neighbor's garage. If it was an early morning launch when things were quiet we could hear the roar of the rockets. That was in Bartow, Florida.

Now watching on TV I get short of breath until the solid rockets separate. Too many bad memories with the shuttles.

When are the shuttle replacements due to launch?

[tangent90]

24. kick.......all systems are go 13 minutes to go

,,,

[AZ homie]

27. Cool, thanks for the heads up!

[Tejas]

29. Welcome to the DU on this special occasion - n/t

[lapfog_1]

42. Welcome to DU.

From a fellow AZ resident. However, I have to say that I'm now trying to get back to California.

[Hope And Change]

28. 6 minutes to go!!

[tangent90]

30. kicking for 2 minutes and counting

3... 2... 1... mark

[csziggy]

31. One Minute!

[tangent90]

32. T - 30 seconds and counting

all go

[Rosco T.]

33. and she's away!

[tangent90]

35. Past "go with throttle up" I can breathe

still recall Challenger (saw personally)
:whew:

[Tejas]

38. I don't mind admitting the first couple of minutes of flight

puts a lump in my throat, eyes often water a little bit too.


All I can think of is "go baby, go".

[lapfog_1]

41. Me too. And with good reason.

Kalpana Chawla was a co-worker of mine, office just down the corridor from mine. I always think about her
when there is a launch or landing.

[RoyGBiv]

43. Same here ...

It starts with that crackling sound just before ignition of the main engines. I can be perfectly composed, not in any way consciously aware I'm about to have an emotional reaction, and then when that starts, I do.

I don't know if it's residual from having watch Challenger when I was in high school or what, but if never goes away.

[RoyGBiv]

34. That will never cease to amaze me ...

Always gives me chills, after all this time.

[Rosco T.]

36. The camera on the tank and can watch it seperate...

and those telescopic camera were you can see the frigging solid boosters seperate ....


"Negative Return" - going to Europe at least :)

[lpbk2713]

37. I saw it from my back yard.

About 100 miles away. Best of luck to the crew.

[lapfog_1]

40. Very cool. I always wanted to see a night launch.

Add one more item to the "bucket list" that will likely never be accomplished.