New answers tagged apollo-program
4
There was no need for guillotines on the Saturn V. Signals between stages were passed through mated electrical connectors, which simply pulled apart during stage separation. There even were pins in the connectors to sense the continuity of the connection. (Sources for this answer are the Saturn V Flight Manual.)
INTERSTAGE DATA FLOW
In order for the ...
4
The "attitude hold" mode holds whatever the current attitude is at the moment when the ACA returns into the neutral position. The DAP does not interfere while the crew is making attitude changes using the ACA, but as soon as they're done with adjustments, the DAP will record and keep the current attitude:
PGNS RATE-COMMAND-AUGMENTATION Mode
(<”...
2
It's an engineering test mockup.
This model incorporates an engineering model of the Descent Stage (used at MSFC, designers of the Lunar Rover, for studies and fit checks) with a fabricated Ascent stage (note the lack of detail in the hatchway area compared to some other LM images)
https://www.americanspacecraft.com/pages/lunarmod/msfc.html
26
It can be hard to see because it's on the front of the PLSS behind the astronaut's helmet.
(NASA photo of Irwin on Apollo 15, I cropped it and added the arrow)
Here's an exploded view showing the vent opening; the sublimator isn't labeled, but it's clearly the same device labeled in the image in the question.
From Apollo EMU Experience Report, I added the ...
3
During the Apollo program, the Saturn vehicle was stacked on the mobile launcher platform. Thus, a platform was in use starting from the stacking of the S-1C stage. This table provides a detailed timeline for each Saturn V launch vehicle and the platform used:
Mission
Stacking start
ML
ML in use*
Launch date
Apollo 4
27 Oct 1966
1
1
9 Nov 1967
Apollo 8
30 ...
11
The CM entered the atmosphere blunt-end first, which became the hottest part during re-entry (see picture below left). So you can't place RCS thrusters on that part of the CM, as they would melt; you can only place them on the sides of the cone, where it stays cooler. Thus, the CM had no aft-facing ($-X$) RCS thrusters.
Note that the side of the CM toward ...
2
Using RP-1 and LOX for the Service Module and the LM was impossible.
Replacing the fuel by a less energetic combination would require larger tanks and different engines designed for another propellant and more thrust for the heavier SM and LM.
A heavier LM and SM would require another much bigger Saturn V, with larger tanks and more engines. Eight or even ...
15
The S-II stages (and actually also the S-IV and S-IVB stages before the Guppy aircraft) were transported by a converted Navy landing ship named the Point Barrow:
(from: Stages to Saturn, chapter 10)
This was an ocean-going ship that took the stages via the Panama Canal (basically the only option; rounding Cape Horn would take much longer and is more ...
-1
So I've accepted that I need to correct my accelerometer readings for the accelerometer offset from the center of mass.
The premise is wrong. There is no need to correct accelerometer readings.
Rockets rotate slowly, if at all. After takeoff, it takes several minutes to pitch over from vertical to horizontal and the acceleration that results from this slow ...
5
There are many problems with your suggestion.
The exact hypergolic combination (Aerozine 50 and nitrogen tetroxide) used by Apollo was already used and proven during Gemini. There was no concern that it would fail. (That was a major purpose of the Gemini program: to prove the technologies needed for Apollo.)
The specific impulse of the RP-1 S-IC first ...
12
If the Surveyor flights had failed to re-ignite the Centaur's RL10, the engine would have been redesigned until it could re-ignite.
While it was theoretically possible to build a moon rocket with kerosene instead of hydrogen upper stages (like the USSR's N1 program), the US had decided early on that hydrogen was more practical for upper stages leaving LEO. ...
6
There are lots of things on spacecraft that are built redundantly. Some are even built to have dissimilar redundancy such as redundant sensors that measure the same thing but are built by different manufacturers. Another example is that some spacecraft have a backup flight software system written by a group of developers who are firewalled from the ...
26
It was very simple. Five sloped straight lines.
The terrain is modeled by a series of line segments leading to the
nominal landing site. Each line segment is
defined by a pair of single-precision erasables; one defines the
slope of the segment, the other defines the range from the nominal site to the segment
end farther from the site.
There's a full ...
1
This answer on the Physics sit seems to sum up the maths pretty well:
With the accelerometer A and the center of mass C we have $\vec{c}
> = \vec{r}_C - \vec{r}_A$.
$$ \vec{a}_C = \vec{a}_A + \dot{\vec{\omega}} \times \vec{c} +
> \vec{\omega} \times \vec{\omega} \times \vec{c} $$
one can you the 3×3 cross product
operator
to transform the above into
$$...
0
I'll have to look for details, but I think that on the outbound flight, the spacecraft had a high but still finite apogee, maybe 2x the lunar distance (700000km or so).
On the way back, I seem to remember that the return flight actually did exceed escape velocity, and therefore was in a hyperbolic orbit around the Earth. The periapse was low enough though ...
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