Launch Complex 39 Q&A

[nathan.moeller]

Are there any pictures of pad 39A or B right after a launch? Would love to see how a pad looks right after launch, Thanks

Just picture them both very wet with steam rising everywhere

This doesn't get very detailed but you can see the water spraying all over the place at 5:28 into the video.

<a href="http://www.youtube.com/v/rFSj2xeUR7M&rel=1" target="_blank">http://www.youtube.com/v/rFSj2xeUR7M&rel=1</a>

[arkaska]

Are there any pictures of pad 39A or B right after a launch? Would love to see how a pad looks right after launch, Thanks

There are some on L2

[spacecane]

How did the "sparkers" actually create the sparks before SSME ignition?  I'm interested in the technical aspects such as what materials were used and how the sparks were "shot out". 

[Jim]

How did the "sparkers" actually create the sparks before SSME ignition?  I'm interested in the technical aspects such as what materials were used and how the sparks were "shot out". 

They are pryotechnics, in other words, fireworks. Not much different than the firework "fountains".

[wolfpack]

How did the "sparkers" actually create the sparks before SSME ignition?  I'm interested in the technical aspects such as what materials were used and how the sparks were "shot out". 

Pyrophoric metal similar, if not identical to, the flint in a common cigarette lighter. Just a whole lot bigger.

Believe it was a wheel of some sort that ejected the metal radially outwards into the area below the nozzles. I remember a TV program about pyrophoricity that mentioned the ROFIs, and explained a bit on how they worked, and then proceeded to fall right into the common misconception that they actually ignite the engines. 

[DMeader]

Believe it was a wheel of some sort that ejected the metal radially outwards into the area below the nozzles.

You're saying a mechanical device, like the wheel on top of a butane lighter? That's not how I understand it to work. I'd love to see a good closeup photo of that part of the TSM.

[AnalogMan]

Here is a short description of the ROFIs ('sparklers') from a technical paper on possible methods of hydrogen disposal at Vandenburg

"Successful hydrogen disposal requires some combination of benign burning, inerting, or venting of excess GH2.  At KSC, radial outward firing initiators (ROFIs) mounted near the SSME nozzles provide an ignition source for unburned hydrogen during the SSME start transient. A ROFI is, in effect, a small rocket motor filled with zirconium pellets.  These pellets flood the area between the SSME nozzles and the duct entrance with small (550-micron), extremely hot zirconium sparklers."

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19890003237_1989003237.pdf

[Robotbeat]

Has anyone thought of doing this for RS-68 engines? Would that even be helpful?

I guess what I mean to ask is: Why didn't the Delta IV get the sparklers?

[Jim]

Has anyone thought of doing this for RS-68 engines? Would that even be helpful?

I guess what I mean to ask is: Why didn't the Delta IV get the sparklers?

They use them and fire them off about the same time in the countdown

[Robotbeat]

Has anyone thought of doing this for RS-68 engines? Would that even be helpful?

I guess what I mean to ask is: Why didn't the Delta IV get the sparklers?

They use them and fire them off about the same time in the countdown

Thanks.

[cyril_13]

Hi all !

Does anybody know what these "deflector-like" things are for ?

(source : youtube video "Space Shuttle Flame Deflector System.")

Comparing satellite views of the Pads 39A (right) and 39B (left) we can see they are quite far from the central deflector (and therefore far from the SRBs) :



But on the Nasa facts sheets they seem to be right under the SRBs


I'm a bit lost there..
Or maybe I'm mixing up 2 different structures ??

Thanks for your help !
Cyril

[Jim]

They are for the SRB exhaust, they are moved into place after the crawler leaves.

[cyril_13]

I see, didn't know they were on rails..
I guess it would be to allow some free space for the crawler ?

[Jim]

I see, didn't know they were on rails..
I guess it would be to allow some free space for the crawler ?

yep

[DaveS]

They are for the SRB exhaust, they are moved into place after the crawler leaves.

Actually, they're moved into launch position as part of S0007.100 Launch Countdown pre-ops.