Apollo stage seperation, but from which?

[trebor]

Does anyone recognise this clip? I had thought it was from Apollo 6.
Yet others seem to think it was a Saturn IB.

[Bob B.]

I don't think it is a Saturn IB. The top of the adapter section is the same diameter as the third stage, but the outer wall appears to be wider as you go further aft. This makes me believe it is the truncated cone-shaped adapter of a Saturn V rather than the straight cylinder-shaped adapter of a Saturn IB.

[macapple]

This is from Apollo 4. The stage going away is a S-IVB for sure and the interstage is clearly that from S-II/ S-IVB not from a s1-b.

There were two cameras on the Saturn V and both were Jettisoned before reaching sub orbital velocity at around 60k m

If you look carefully whilst the " tube" holding the stage is straight the surrounding sides move away at an angle. This mission had cameras on all the stages and was the first to provide the famous footage of the interstage rings falling away.

[laurel]

Mar 6, 2010 23:51:02 GMT -4 macapple said:

This mission had cameras on all the stages and was the first to provide the famous footage of the interstage rings falling away.

I'm starting to think there's a rule that you can't make an Apollo documentary without including that footage.

[Jason Thompson]

I am certain that footage is from a Saturn IB. The S-IVB has three ullage motors on it, the APS rockets are rounder, and the thrust structure lacks a significant number of helium spheres. That indicates a 200 series S-IVB rather than a 500 series. I think the apparent widening of the interstage is simply an optical effect from the use of a wide-angle lens.

[ka9q]

I had also thought this was from Apollo 4 or 6, but I no longer think so.

The main clue? The 3 ullage rockets on the S-IVB (upper) stage. The S-IVBs on Apollos 4 and 6 had only two ullage rockets while those on AS-201, AS-202 and AS-203 (unmanned test flights of the Saturn IB) had three.

While all three IB flights describe upward-looking cameras on the S-IB stage, there is no mention in the Apollo 4 and 6 reports of any upward-looking cameras on the S-II. The only Saturn V ejected film cameras mentioned are those on the bottom of the S-II that produced that famous S-IC/S-II separation footage. At any rate, retrieving cameras ejected at the end of S-II flight would be very challenging.

I am not prepared to say which of the three flights this footage is actually from. One clue might be the angle of the sun and the daylit earth underneath. AS-201 was launched at 1612 UTC in February, AS-202 at 1715 UTC in August, and AS-203 at 1453 UTC in July. Separation would be a fairly short distance east of Cape Canaveral, so AS-201 would be roughly 11am, AS-202 1pm and AS-203 11am - not much of a spread.

[macapple]

I think this is where the confusion lies, and now im confused.

I have read through some of the mission documentation and it does seem conflicting.

On the Ullage motors.

There were two distinct Ullage firing sequences one pre main engine start and one further on after a sequence shows 2 Ullage engines being jettisoned. This sounds to me like there were 4 ullage engine locations, 2 external/internal and 2 which were part of the APS.

Source :fig 7 page 15

klabs.org/history/history_docs/jsc_t/apollo_04_technicalOinformation_summary.pdf


Ive also found that there was provision for Ullage engines in the APS here . With 2 ullage rockets in each APS = 4 rockets in two APS. (http://www.astronautix.com/engines/se7.htm).

It is not clear though if only 2, 3 or 4 ullage rockets were fired on the separations, in the reports ive read through so far.

Cameras

You are correct I can only find one reference to cameras and those are in the place on the SII to view the S-IC/S-II rocket fire and separation.

I will read through some more books i have to see where the S-IVB camera is mentioned and what missions.

[ka9q]

I think the Saturn V had only two solid ullage motors on the S-IVB, while these early S-IB flights (AS-201, -203, -202) had three. You can clearly see three in this footage. Furthermore, the motor on the left appears to be underperforming its brothers, and I am pretty sure that one of these three mission reports mentions a bad ullage rocket. So that's probably the mission that produced this film.

Only two of these S-IBs had Apollo CSMs and escape towers, but unfortunately we can't see the top of the S-IVB so we can't go by that.

[Bob B.]

The 500-series S-IVB had two ullage motors spaced at 180^o and two APS pods located between the ullage motors. The two solid-propellant ullage motors were fired at S-II/S-IVB separation, which were then jettisoned during S-IVB flight. The APS pods also contained ullage engines that were fired prior to re-ignition of the S-IVB for TLI.

The 200-series S-IVB had two smaller APS pods and three ullage motors.

[bazbear]

Wow, it's amazing what things you learn here, in this case just from a discussion about which mission this footage came from. I knew what "ullage" meant, the "empty" part of a fuel tank (or other tanks with liquids) at the top, so "ullage motor" had me baffled until I did a little research. I'd never considered that in micro-gravity, to keep the liquids where you want them after a staging when there is no thrust (and hence no gees), something would have to push the fluids back (even if only small fractions of a gee).

[clipperride]

I did think that the clip was from the Saturn V, Apollo 4 launch when I first saw it, but I'm not 100% sure. I have a copy of "The Mighty Saturns - Saturn V" from Space Craft Films, which shows all of the Saturn V launchs and this shot does not appear in the Apollo 4 footage.

On the matter of the number of ullage rockets, as far as I am aware, the number used changed through out the programe.

So, I think it is probably Apollo 4, but possibly one of the earlier Saturn 1b tests. I hope someone can tell us which mission it did come from ?

[Jason Thompson]

Apr 1, 2010 12:57:26 GMT -4 clipperride said:

On the matter of the number of ullage rockets, as far as I am aware, the number used changed through out the programe.

The number of ullage rockets on the interstage between the S-IC and S-II stages changed, with 8 on Apollo 4 and 6, 4 on Apollo 8-14, and none at all from Apollo 15 onwards.

On the S-IVB there were always two ullage motors on the 500-series used on the Saturn V and always 3 on the 200-series used on the Saturn-IB. That's the giveaway that the footage here did not come from any Saturn V flight.

[clipperride]

After having a look online and in the excellent "Apollo - The Definitive Sourcebook" I think I may have found where this clip comes from.

Looking at the Footage Vault site, the clip is listed as being from AS-202, which was the third test flight of the Saturn 1b. It carried the Block 1 CSM-011 and although one of the ejected camera pods was not recovered the other was found only 2nmi from the S1b impact site.

Check out

www.footagevault.com/clip/FTV-0002000/apollo+3/all

So, hopefully, question answered!

Regards

Mark.

[ka9q]

Apr 2, 2010 4:05:01 GMT -4 Jason Thompson said:

The number of ullage rockets on the interstage between the S-IC and S-II stages changed, with 8 on Apollo 4 and 6, 4 on Apollo 8-14, and none at all from Apollo 15 onwards.

Are you sure about that? I remember some rockets being deleted from Apollo 15, and that resulted in the S-II plume hitting the top of the S-IC and killing some telemetry transmitters. It wasn't a catastrophe since the S-IC had already done its job, but I recall that some rockets were put back on to prevent a recurrence.

Note that staging generally involved both ullage and retro rockets. The ullage rockets were on the upper stage and fired down to settle the propellants into the intake manifolds, while the retrorockets were on the lower stage and fired up to back the lower stage away. When you think about it, something has to be done to separate stages at staging because they are otherwise in free fall.

Some rockets don't need dedicated ullage rockets. E.g., the Apollo service module could use its reaction control thrusters for that purpose, and that was only needed after an initial burn had depleted some of the propellants and left empty spaces (ullage) in the tanks. The first SPS burn could take place without an ullage burn.

The RCS engines themselves don't need ullage burns (which would be pretty inconvenient!) because their propellants are stored in bladders and squeezed out by gas pressure, either He or N2 I think.

[Jason Thompson]

Yes, I am very sure. The S-IC ullage rockets are very clearly visible on the interstage, so it's a simple matter to see how many were on each rocket. If retro rockets were changed I don't know, because they are not visible on the S-IC, being inside the engine fairings.