Apollo return fuel requirements?

[bknight]

The description of the components makes sense, and visually form the damaged CSM are spatially correct.  I haven't read the whole transcript of AS13, but where either one of the fuel/oxidizer tanks damaged?  With condition of the equipment bay, the innovative mission constraints presented a challenge for the engineers on the ground for sure.  The mission was the first that I didn't follow live, as I was in basic training and no TV's or radios were allowed.

[Bob B.]

I am unaware of any damage to the fuel tanks.  To my knowledge the damage was limited to sector 4, which included the three fuel cells (toward the top of the bay), two oxygen tanks (about the middle of the bay), and the hydrogen tank (toward the bottom of the bay).  I can clearly see two of the fuel cells in the photograph (the other is behind).

I followed the Apollo 13 mission very closely when it happened.  I was coming up on my 12th birthday at the time.
 

[bknight]

I can see two objects side by side toward the front end at about 0200 are those the fuel cells?  Also there is a rectangular piece at the front end 1200 is this a "hold down" for the command capsule in a released position?
There are other pieces at 0300 that appear to be on the outside (maybe one piece with a couple of lobes), what do you think they(it) might be?

[Bob B.]

I can see two objects side by side toward the front end at about 0200 are those the fuel cells?

Yes.  Here's a photo that might help to identify them...

Also there is a rectangular piece at the front end 1200 is this a "hold down" for the command capsule in a released position?

That's a cover that went over the umbilical lines that ran between the SM and CM.  You can see it below...

There are other pieces at 0300 that appear to be on the outside (maybe one piece with a couple of lobes), what do you think they(it) might be?

I can't positively identify any of that other debris.

[bknight]

Out of all the launches I've watched I never noticed that cover.  Was it on the opposite side of the vehicle from the launch tower?
Thanks for the time and effort.

EDIT: Added question

[Bob B.]

Out of all the launches I've watched I never noticed that cover.  Was it on the opposite side of the vehicle from the launch tower?
Thanks for the time and effort.

The umbilical cover was opposite the CM hatch.  So yes, where ever the tower walkway was located, the umbilical cover was on the opposite side.

[Bob B.]

So yes, where ever the tower walkway was located, the umbilical cover was on the opposite side.

Clarification...  I forgot that the hatch didn't directly face the launch tower.  The walkway was offset a little to the side.  After the astronauts crossed the walkway they had to turn to their right to enter the capsule.  If the tower is at 12 o'clock, the hatch is about 3:00, and the umbilical cover about 9:00.

[bknight]

So yes, where ever the tower walkway was located, the umbilical cover was on the opposite side.

Clarification...  I forgot that the hatch didn't directly face the launch tower.  The walkway was offset a little to the side.  After the astronauts crossed the walkway they had to turn to their right to enter the capsule.  If the tower is at 12 o'clock, the hatch is about 3:00, and the umbilical cover about 9:00.

But that should be pointing at most of the broadcast camera locations.  I still don't see it, I wished I knew how to zoom YT.

EDIT: Whole comment line.

[ka9q]

I don't think the SPS propellant tanks had bladders. The +X RCS engines were fired for a few seconds to settle the SPS propellants before the SPS engine was fired; the burn pads make reference to "ullage", the length of this pre-burn. It was not necessary when the tanks were full.

I believe the RCS propellant tanks did have bladders to ensure they'd work in 0g.

I believe the same is true for the LM.

[ka9q]

There were two fuel tanks and two oxidizer tanks for the SPS. One tank fed into the other, which fed the engine. The one in the middle was called the "sump" tank, and was depleted only after the corresponding storage tank was emptied.

I'm not sure why this was done, but I'd guess it was to maintain good mass properties of the stack as the propellants were depleted.

[bknight]

There were two fuel tanks and two oxidizer tanks for the SPS. One tank fed into the other, which fed the engine. The one in the middle was called the "sump" tank, and was depleted only after the corresponding storage tank was emptied.

I'm not sure why this was done, but I'd guess it was to maintain good mass properties of the stack as the propellants were depleted.

That seems inefficient, unless one pump fed the first tank into the second and finally into the rocket engine.  However it was constructed it did the job required.

[Allan F]

There were no pumps, only helium pressure in the tanks to drive the fuel into the engine.

[bknight]

Of course how stupid of me.  But I remember a conversation in another thread that the helium disk burst on AS13 requiring the RCS to make the final flight correction.

[Allan F]

Yes, on the LM, not the SM.

[Zakalwe]

Of course how stupid of me.  But I remember a conversation in another thread that the helium disk burst on AS13 requiring the RCS to make the final flight correction.

That was on the LM.