Author Topic: Shuttle Q&A Part 5  (Read 837048 times)

Offline spacenut

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Re: Shuttle Q&A Part 5
« Reply #3460 on: 08/26/2017 12:50 PM »
I turned 16 the day they landed on the moon.  I was hoping for us to go to Mars by the mid-1980's.  Shuttle was OK, but instead of building a space station, maybe they should have built a Nautilus-X type spacecraft so we could use it as a shuttle to and from Mars or the moon.  It would have at least kept our exploration going. 

Hopefully SpaceX will be the first to get a larger ITS spacecraft into orbit and be able to land it.  Then go beyond LEO. 

Offline eric z

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Re: Shuttle Q&A Part 5
« Reply #3461 on: 08/26/2017 12:58 PM »
 Hi Dosobo, Welcome and have fun here! You ask a great question...sometimes we can get so lost in the trees, we don't see the forest, or vice-versa! There are many reasons we are where we are today, and you are about to be flooded with a lot of well-informed opinions, and maybe even some not-so well informed. Let's see what you think a few pages into this thread after getting hopefully thoughtful and diverse views. Keep an open mind, I've certainly had my eyes opened here, and have changed my mind on some things, but also have renewed strength in other things I believe in. Also, if you can, and maybe you already have, join L2 for even more extensive FUN!  8)

Offline Weasel Pilot

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Re: Shuttle Q&A Part 5
« Reply #3462 on: 09/15/2017 10:38 PM »
Both the LOX tank and the LH2 tank had four sensors at the 100% level - a low sensor, two (assumedly) median sensors and a high sensor (plus other sensors at the 98% and overfill levels). Does anybody know how much space there was between the 100% low sensor and the 100% high sensor?  In other words how much vertical space did 1% of propellant take up in the tank?  Obviously due to the tank shapes this would vary with location in the tank, but at the top (100% level) does anyone know what this was?

Dave

Online brickmack

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Re: Shuttle Q&A Part 5
« Reply #3463 on: 09/15/2017 11:23 PM »
6 inches for the LOX tank, 8 for the LH2 tank

Offline Weasel Pilot

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Re: Shuttle Q&A Part 5
« Reply #3464 on: 09/20/2017 12:16 AM »
Thanks! Awesome response!!

Offline Weasel Pilot

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Re: Shuttle Q&A Part 5
« Reply #3465 on: 09/20/2017 05:58 PM »
Which begets another question...or actually five -
1. The tank fill schedule (as I understand it) was low flow to 2% then high flow (5,000 gal/min) til 98% then low flow again to 100%
      a. What was the low flow rate?
      b. How do it know?  No 2% sensor...
2. The feed lines openings were offset (as I measure it, 10 degrees for LOX and 6 degrees for LH2). 
      a. I ASSUME that this was to make up for gravity effect, si or no?
      b. Why are these not the same? (density delta twix LO2 & LH2?)
      c. Was the offset towards or away from the orbiter?

Dave

Offline mkirk

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Re: Shuttle Q&A Part 5
« Reply #3466 on: 09/20/2017 06:52 PM »
Which begets another question...or actually five -
1. The tank fill schedule (as I understand it) was low flow to 2% then high flow (5,000 gal/min) til 98% then low flow again to 100%
      a. What was the low flow rate?
      b. How do it know?  No 2% sensor...
Dave


There is a lot packed into those questions, so let me take the first one since I can answer that pretty quickly and easily.  If someone else doesn't beat me to it, I will try and come back with a good answer to the second question later.

Slow Fill for LO2 to 2% level was based on time (about 11 minutes) at a flow rate of about 270 gallons per minute.
Fast Fill for LO2 to 98% level sensor was at around 1300+ gallons per minute.
LO2 Topping occurred at approximately 800 gallons per minute.
LO2 Replenish was in the neighborhood of 100 gallons per minute.

The launch vehicle was "designed to accept" 5000 gallons of LO2 per minute.  This was from a DOD requirement for so called "rapid response" launching of the shuttle.  However, the facility at KSC was only capable of delivering about 1400 gpm.

Slow Fill for LH2 to 5% occurred at a flow rate of 1200 gallons per minute until the 5% sensor was wet.
Fast Fill commenced at around 6900 gallons per minute until about the 85% level, then switched to "Reduce Fast Fill" until the 98% sensors were wet.
LH2 Topping to the 100% sensor occurred at about 600 gallons per minute.
LH2 Replenish was approximately 200 gallons per minute.

Mark Kirkman
Space Shuttle Hugger and NASA Geek
« Last Edit: 09/20/2017 07:21 PM by mkirk »
Mark Kirkman

Offline Jim

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Re: Shuttle Q&A Part 5
« Reply #3467 on: 09/20/2017 07:58 PM »

2. The feed lines openings were offset (as I measure it, 10 degrees for LOX and 6 degrees for LH2). 
      a. I ASSUME that this was to make up for gravity effect, si or no?
      b. Why are these not the same? (density delta twix LO2 & LH2?)
      c. Was the offset towards or away from the orbiter?

Dave

No, they were offset due to orbiter hanging off the side of the ET and creating an offset CG and hence, the centerline of thrust was not parallel to the centerline of the ET

Towards the orbiter

Offline Weasel Pilot

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Re: Shuttle Q&A Part 5
« Reply #3468 on: 09/21/2017 08:01 PM »
Thanks again!  Excellent response/info.

I'm trying to get my (very) limited grey matter wrapped around the offset CG thing - I realize why the CG was offset, but did the offset cause/require a pitch that in turn caused the feed ports to be "canted"?

Online wolfpack

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Re: Shuttle Q&A Part 5
« Reply #3469 on: 09/21/2017 08:16 PM »
Thanks again!  Excellent response/info.

I'm trying to get my (very) limited grey matter wrapped around the offset CG thing - I realize why the CG was offset, but did the offset cause/require a pitch that in turn caused the feed ports to be "canted"?

Thrust (acceleration) vector. It's not "straight up" through the ET.

Offline Jim

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Re: Shuttle Q&A Part 5
« Reply #3470 on: 09/22/2017 01:22 PM »
Thanks again!  Excellent response/info.

I'm trying to get my (very) limited grey matter wrapped around the offset CG thing - I realize why the CG was offset, but did the offset cause/require a pitch that in turn caused the feed ports to be "canted"?

If the thrust vector does not go through the CG, then there is a moment and the vehicle rotates. 
« Last Edit: 09/22/2017 01:32 PM by Jim »

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