# Tag Info

41

Had a bit of a gander at what NASA Technical Report Server and Semantic Scholar had to offer and found a couple things that I reckon might be helpful. NASA created a 1/10 scale model of the Saturn V for a study vehicle dynamics and you can read the report here This gives us these two schematics. They also created a 1/25 scale model for aerodynamic testing. (...

38

They used the Mobile Service Structure (MSS), which for some reason is rarely shown in Apollo pre-launch photos. The large work platforms at upper right completely surrounded the spacecraft and the upper section of the S-IVB stage, which held the Lunar Module. From these platforms, technicians could make last-minute changes to the flight hardware. ...

27

There's a more detailed profile drawing available for download at the bottom of this Heroic Relics page. Here's a representative slice: It used to be possible to get an inexpensive print of a cleaned-up, white-on blue version of this, 180cm long. (I have one, it's beautiful. The custom frame cost much more than the print.)

21

At least for some vehicles, "dynamic pressure is closely monitored" is not correct. You need to have an air data probe to actually monitor it, and not all vehicles do. Shuttle: Dynamic pressure was not actually measured1 during ascent so "Max Q" was not either. The magnitude and time of Max Q was predicted by prelaunch simulations, and ...

21

Excess capacity was needed in the storage sphere to allow for multiple attempts in a launch campaign. Much of the propellant was recovered during a scrub but not all. The storage spheres were loaded from waves of tanker trucks and it was a lengthy process - weeks to several months. It would have been embarrassing to run out of propellant after a series of ...

18

The most familiar issue is that the Apollo 10 LM was still above its target weight by a couple of hundred pounds. A safe landing would have been physically possible, but not with the desired propellant margins. However, the lighter Apollo 11 LM had already been completed and delivered 4 months prior to the flight of Apollo 10 -- the production and assembly ...

16

The Instrument Unit was retained after Skylab reached orbit, and was instrumental (sorry) in configuring the station for orbital operations. From Skylab: A Guidebook: Control of the Saturn V launch vehicle during launch and powered flight will be accomplished by guidance and control systems located in the Instrument Unit. This function will be maintained by ...

16

The thrust deflectors on the descent stage were added to Eagle when it was already stacked on the Saturn V after the flights of Apollo 9 and 10 showed that the exhaust from the downward-facing attitude thrusters were impinging on the structure. Also, not really as a result of the test flights, the ground contact probe on Eagle's forward footpad was removed ...

16

Helium was used to pressurize the RP-1 tank to save weight. Nitrogen is much cheaper but its density is 1.250 kg/m$^3$, helium is 0.1785 kg/m$^3$, so 1.071 kg is saved for every cubic meter of emptied tank volume. To pressurize a fuel tank with pure oxygen is a bad idea, only inert gases like nitrogen or helium may be used. The first stage RP-1 tank volume ...

14

Because all you have to do to get gaseous oxygen is take liquid oxygen and warm it up a bit. That means just tapping off a little gas from the engine and routing it back to the tank to keep the ullage pressure where it needs to be. Contrast that with RP-1, which doesn't really vaporize enough to get the pressure where it needs to be. For that, they had to ...

13

Are there any statements from astronauts with Apollo and Shuttle experience about vibrations and noise in comparison? John Young: Q: How did the launch compare to the Saturn V? JY: "It didn't shake near as bad but there were a little more Gs [forces of gravity] — 1.2 Gs on the Saturn V, 1.5 Gs at liftoff on the shuttle. We only got up to 3 Gs, well, ...

11

I suspect this is a duplicate. But here are two quotes from Chariots for Apollo by Courtney G Brooks, James M Grimwood, Loyd S Swenson Jr (this seems to be online here although I didn't discover this until I'd typed the below from my physical copy). Chapter 2 is what you want to look at, from which page 49, bottom to page 50, top, my interpolations in [...

8

If the upper stage is fired promptly after first-stage shutdown, it's possible that no ullage is needed at all. The thrust from the first stage engines settles the upper stage propellants. Any separation impulse between the stages tends to keep them settled, and there isn't enough time for any of the ullage gas to drift to the engine inlets before the upper ...

8

To build a translunar stage of around 80 tons from the 7 ton payloads that could be launched on the Soyuz booster would require extensive assembly work to be done by astronauts in orbit, which was beyond the experience of either the US or the USSR in the 1960s. Before settling on the single large Saturn V and lunar orbit rendezvous, the US contemplated using ...

8

No N1s remain intact as far as I know. Wikipedia is pretty clear about the disposition of the individual N1s constructed. I found a photo gallery showing various scraps and wreckage from the N1, including a garden shed made from a payload fairing, but the origins of the pictures is unclear. Astronautix claims the "gazebos" are at Baikonur, which ...

6

Partial answer: I can identify the manager responsible for the decision, and the date, but not the reason why. LC-39 was the sole topic at a meeting of the Launch Operations Working Group on 18-19 July [1962] that brought together 113 representatives from LOD, MSFC, and the launch vehicle contractors: Boeing, North American, Douglas, and General Electric. ...

6

This depends on to what degree you define the SA-500D as "a full Saturn V". All components of it where certainly stacked vertically at the Saturn V Dynamic Test Stand, as can be seen in the 1966 Wikimedia photo below. (also includes a simple Apollo mockup). "Full stack" was called "Configuration I" The only test article of the ...

6

Chariots for Apollo NASA SP-4205 (1979) By Courtney G. Brooks, James M. Grimwood and Loyd S. Swenson, Jr. (web version) (pdf version) Moonport NASA SP-4204 (1978) By Charles D. Benson and William Barnaby Faherty (web version) (pdf version)

5

There are ways to measure dynamic pressure, and in aerodynamically complicated spacecraft (like the shuttle) if measured on its three four "nosecones" it could conceivably occur at (at least somewhat) different times in different places. And yet when we watch a launch there is a specific time when the announcer calls out "Max-Q!" at which ...

5

The center of mass of the Saturn V at liftoff is somewhat lower than you might expect -- 27 meters up, about a quarter of the way up the stack. This is because the upper stages are largely filled with liquid hydrogen, which is much less dense than the fuel and oxidizer in the first stage. Thus the yaw moves the upper end of the rocket much further than the ...

4

A "throat plug" is a cover to prevent contamination from entering the engine's combustion chamber from the direction of the nozzle. It can also serve as a "stopper" for leak testing. I could not find a picture of an F-1 throat plug, but here are some diagrams of the Space Shuttle Main Engine's throat plugs. This diagram shows the upper ...

4

There isn't that much of a difference after all. It's mostly a matter of perception because the R-7 family evolved into many different variants, so it feels like most Soviet launch systems use liquid boosters. Proton, for example, doesn't use any strap-on boosters. The following "early ICBM" designs of the early 60's are actually pretty similar: R-7 with ...

4

The A11 press kit has some information about the MSS: So the MSS is secured to four mount mechanisms. But no details about it. Wind loads were a second major concern for the tower's designers. On 28 March representatives of the Marion Power Shovel Company, the Corps of Engineers, LOC, and Rust agreed to design for a maximum wind velocity of 100 ...

4

Warning: this answer contains unsupported opinions. I don't believe the events after dropping the S-II are generally referred to as staging, but I think at least the S-IVB/CSM separation event could be considered staging. Separation of S-IVB on one hand, the LM+CSM on the other hand. Not clear if this is considered as a staging event. While not usually ...

4

Ullage for the Apollo command/service module and the lunar module was performed by those reaction control system engines which pointed in the same direction (+X) as the main engine. These engines are essentially digital in nature; they are either off or on. Some control modes allowed the RCS engines to be pulsed for finer control. However, ullage burns ...

3

Looking at for instance the list of events for Apollo 11, there are no "staging events", just a number of "separations". On the other hand, if we are counting everything with a "stage" in the name, there are a total of five stages, three on the Saturn V and two on the lunar module. To make a slightly different point than Russell ...

3

The accelerometer's axes in a strapdown IMU are not aligned with inertial. The sensed acceleration must be transformed to inertial to perform the integration. This can lead to issues if the rocket's or spacecraft's orientation with respect to inertial is not well known. The vehicle's orientation with respect to inertial is fairly well known once the vehicle ...

3

There are different numbers on this NASA page about Saturn V: Finally, the fuel squirted through 3 700 orifices into the combustion chamber to mix with the oxidizer, which entered through 2 600 other orifices in the injector face If the hole numbers of the question are correct, (1428 Oxidizer holes and (approximately) 1404 Fuel (RP1) holes) the explanation ...

3

With some googling I found a web site with a reference to the F-1 test stand being at the coordinates 34.944, -117.688. Following that to the Google maps link, in satellite mode one clearly sees the remains of 2 test stands. The one on the right matches the F-1. As for Santa Susana, an article in the Daily News has a picture indicating there was something ...

2

From Wikipedia: During static test firing, the kerosene-based RP-1 fuel left hydrocarbon deposits and vapors in the engine post test firing. These had to be removed from the engine to avoid problems during engine handling and future firing, and the solvent trichloroethylene (TCE) was used to clean the engine's fuel system immediately before and after each ...

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