[Firestarter]

The not tested descend/ascend

I repeatedly call lack of testing an important argument against the Apollo moon landings. I think this is a good time to explain a little on “testing”...
I guess that testing of planes is more similar to software testing than the testing that should be done in “rocket science”, but the links I found to come up with a “test strategy” is relevant in this context (at the very least it explains how I look at it).

While landing on the moon is associated with an extremely high risk. For which no appropriate, feasible “testing strategy” could be designed, making a handful of movies on “moon landings” with some special effects wouldn’t be a risk.
With the media under complete control there is no chance that the fraud would ever be exposed (is there?).


In (software) testing deciding what to test is decided based on the (estimated) risk.
Risk is assessed by a team of “stakeholders” and based on multiplying (maybe there are better formulas…):
Probability * Severity

Probability is the chance an error would occur after implementation of the software. This is mostly decided on the complexity and the frequency functionality is used.
Severity is the damage a failure would cause. In software development arguably the worst that could happen is that an error brings the whole system down: http://www.methodsandtools.com/archive/a....php?id=31


When I relate this to the testing for the Apollo moon landings, the risk is enormous, which means I expect that basically every small detail of the moon landings would be tested with hundreds of test cases.
The complexity of a moon landing is especially large as never before people landed on the moon. There are even many factors about landing on the moon (and the trip) that were (are) simply unknown.

Even more damaging for the credibility of this “event” is that not even the tests that could have been performed (if a moon landing is feasible) on earth were done.
While the descend and ascend couldn’t be tested in vacuum at all, they could have tested with something like a light version of the Lunar Module:
Landing a “lunar module” after a starting speed of 6000 km/h (4 times the top speed of an F-16).
Lifting off a lunar module to reach a speed of 6000 km/h…

In my opinion, the most important problem to overcome in (real) Apollo moon landings, is the problem of gravity without an atmosphere (vacuum).
1) It would be very difficult to land on the moon (without smashing), impossible as they couldn’t test this.
2) Lift-off from the moon could be even more impossible (and again couldn’t be tested).
3) The probe would have to overcome the gravity until it would reach the rocket. Reportedly the rocket was still circling around the moon, so it would also be difficult to connect with the rocket.
This amazing feat never once went wrong: every astronaut in the 6 missions to reach the moon… got safely back to earth.

They also had to overcome the gravitation from the moon (besides the starting speed)...
See how the Lunar Module descends.


The following shows how the Lunar Module had to turn in the last phase of the descend.
Not only was it important to have a low vertical speed when landing. It couldn’t have any horizontal speed at landing (unlike landings on earth that often use wheels).



The following video shows the descend/ascend “testing” of the Lunar Module (engine) done on earth, with the Lunar Landing Research Vehicle (LLRV, that looks very similar to a modern day drone). They also did flights with LLTVs...
At 12:50 you can see the lift off (notice the acceleration) and also notice the wheels (for the record, it isn´t claimed that the lunar module had wheels)!
https://www.youtube.com/watch?v=s2ejvFX7Q20


I’ve been thinking about some “comparable” experiment to the landing on the moon of the lunar module that could be done on earth.
An ice buggy, with no steer or anything to keep it in a certain direction (like sharp irons) or brakes. It has an incredible powerful motor (like the engine of an F-16). The engine is “throttleable” but it can’t be turned in any direction for steering.
Now this ice buggy is going with a speed of 6000 km/h over an ice lake, there is no wind and the shore of the lake is at 10 km. The ice buggy has to use its powerful engine to stop before it crashes on the shore. Please don’t try this yourself!



According to NASA, the lander had 2 large rockets, one for the descent and another for return to the Central Module (circling around the moon at 6000 km/h), and 16 “control engines” with a small thrust.

The lunar module descent engine was the biggest challenge for the Apollo missions. Never before had a throttleable engine been designed for manned spacecraft. The engine also was gimballed so that it could “shoot out” its thrust in the wanted direction.
Because the fuel was so corrosive, the engine couldn’t be tested before launch.

There was also the huge problem of cooling the combustion chamber for which supposedly radiation cooling was used (sounds very science fiction!): https://www.hq.nasa.gov/office/pao/Histo...ch6-5.html


The Lunar Module "started" the descend at 102:33:05.01; Altitude: 10.3 km; speed 6106 km/h.
The Lunar Module landed at 102:45:41.40.
In 12 1/2 minutes it supposedly went from a speed of 6106 km/h to (almost) 0; most of the speed was only lost in the final stages of the descend: https://history.nasa.gov/SP-4029/Apollo_..._Phase.htm


Following is an interesting interview with some important NASA actors.

How did they prevent the rocket ship from burning up in the sun light?

Chris Kraft, director of flight operations, Mission Control: On the way to the moon, you might say, "Well, that could be a pretty boring time." But that's not true. There were times when you had to do things with the fuel cells, when you had to get rid of the water in the system. You're making sure the thermal operation of the spacecraft is being done well. On Apollo it was called barbecue mode.
Hugh Blair-Smith, software engineer for the Apollo guidance computer, MIT Instrumentation Laboratory: For the long three days from the Earth to the moon they had to keep the spacecraft rotating just like a pig on a spit so the sun wouldn't be concentrated on any one side.

The Lunar Module (engine) couldn’t be tested at all in vacuum. They didn’t even perform the tests that could have been done. The on-board computer couldn’t even handle the tasks it had to do.

Steve Bales, guidance officer (GUIDO), White Team, Mission Control: When we came in that morning, the lunar module was dead. We had to power it up, get the thing aligned and checked out. In the simulations, that's where we'd always had the biggest difficulty, really. We had never completed without some major problem--and I don't know if we ever completed successfully in training--what we called a power-up and initialization of everything, and then gone ahead and done a landing.
Joe Gavin, director, Lunar Module Program, Grumman Aerospace Corporation: The whole thing was tense, because we were basically aircraft designers. In the aircraft business you always flight tested something before you delivered it. In the case of the lunar module, you couldn't flight test it. Every launch was a brand-new vehicle.
Doug Ward, NASA public affairs officer: The computer was simply saying, "Hey, I've got more than I can handle, but I'm gonna do the important things, so don't worry about it."

Neil Armstrong: The powered descent was the most challenging segment of the flight. The systems were heavily loaded, the margins were slim, and this would be the first time that the entire descent strategy would be fully tested. A decade earlier, while I was flying in the X-15 program, we learned, surprisingly, that all the pilots, while flying the X-15, had heart rates between 145 and 185. It reflected the mental intensity appropriate for a challenging situation. The Apollo data seemed to correlate well with our prior experience.
Joe Gavin, director, Lunar Module Program, Grumman Aerospace: The lunar module had the first really throttle-able descent engine. When it first fired, it had to operate at about 10,000 pounds of thrust. But as they approached the lunar surface, the vehicle became much lighter, having burned up a lot of fuel, and they had to get the thrust down to maybe 2000 pounds. So it was quite a development to get a rocket engine that would not only do this, but would operate smoothly in either range.
Gavin: In an airplane you usually have, oh, at least an hour's extra fuel in case the airport is closed where you're going. But in the case of the lunar module, we had about 120 seconds of margin.

Nobody had ever been on the moon. There was no way of knowing that, even if landing was possible, the module wouldn’t sink or the surface otherwise wouldn’t be lethal to the astronauts.

Gavin: When we started all this, we didn't know what the surface of the moon was like. We went ahead with a very conservative landing gear design because there never had been a rocket-propelled vertical-landing machine.
Bruce McCandless, astronaut (CapCom), Green Team, Mission Control: It was a relief that the dust on the lunar surface was actually only half an inch deep.
Don Beattie, program manager, Apollo Lunar Surface Experiments: Another [concern] was that the dust would be pyrophoric--that when they opened the cabin of the lunar module, oxygen would react with dust and explode. There was no way we could be sure until the guys opened up the door and the oxygen flowed out.

The lift off of the lunar module also wasn’t tested. The Apollo 17 lift off violates the laws of physics as the Lunar Module doesn’t slowly accelerate.

Gavin: In my mind, the riskiest unknown in the whole mission was the takeoff. When the astronaut pressed the button, a whole bunch of things had to happen. The explosive bolts connecting the two stages had to fire. And then the ascent engine had to be ignited to lift the ascent stage off. And somehow as it left the descent stage, the exhaust from the ascent engine had to go somewhere.
Buzz Aldrin: It was not a gradual liftoff. It was a sudden departure--but without any of the forces that go along with rapid acceleration. Looking out the window, everything was getting smaller so fast that [we didn't really notice] the craft going through a gradual pitch forward.

Because much of the Moon landings couldn’t be tested if I had been the Test Manager, I would have advised against landing on the moon.

Alan Kehlet, Apollo chief project engineer, North American Rockwell: Some guy ran an analysis of all the critical events that had to take place and came to the conclusion we didn't have enough reliability, that it would never work. But we discarded it.

https://www.popularmechanics.com/space/m...apollo-11/