A few questions about space exploration.

There are several things about space travel that I've always wondered about. Things that just don't seem to make any logical sense. I'm beginning to think we never did really go to the moon. My questions are the following:

1) Did the first space suits really have no protection from radiation?

2) Why did the Lunar Module clearly not leave a blast crater?

3) An extremely small piece of debris zipping through space could easily tear a hole in a space suite, has that ever happened? I don't mean on the surface of the moon as most small debris would be sucked in by the moons gravity.

4) An ice-crystal would be vaporized the moment it came into contact with raw sunlight in space, so how come they can float along pulsating/reflecting sunlight for extremely long periods of time?

You can answer by linking to other threads which cover the question, I don't really care. I've just always wondered about these few things and would like some answers.

Yeah I have wondered question 4 as well.

I also think it's weird when you see videos of shuttles close to Earth and see the sun at the side, I would have expected the sun to light up space all around.

reply to post by RANDOMguess

I would have expected the sun to light up space all around.

I'm not exactly sure what you mean, but empty space will remain black simply because it's empty, there's nothing to reflect the light.

EDIT: And what's with the lack of response, can no one seriously answer these questions?

COME ON SKEPTICS!!!

You guys need some motivation or something?

This is a challenge, you must stop me before I believe all sorts of crazy things!!!

Originally posted by WhizPhiz
COME ON SKEPTICS!!!
You guys need some motivation or something?
This is a challenge, you must stop me before I believe all sorts of crazy things!!!

Start with this 300+ page thread..
www.abovetopsecret.com...

reply to post by backinblack


Good call.

I'm sure everything has been asked and answered in there...thrice

reply to post by WhizPhiz


The first space suits had limited protection from radiation, but it turned out that much more protection was needed.

The Lunar Module engine was powerful enough to blow away some dust, but the hard, rocky soil was much to strong to allow any cratering on descent. On ascent, the upper module used the lower module as a launch base.

The EVA suits have heavy protection against micrometeorites, but on several occasions the suits were penetrated. In the suit mechanisms, there is an emergency overpressurization system to increase the internal pressure to allow the astronaut to immediately return to the middeck airlock. The largest hole meant that astronaut had only seven minutes to reach the safety of the airlock or he would have had a decompression event.

Ice crystals initially remain ice crystals because of the extremely low pressure and very cold temperatures of space. Prior to entry, they do turn the left side of the orbiter toward the sun to melt any "waste ice" that may have formed from the liquid evacuation vent from the toilet. The crystals from the toilet have been known to reach sizes up to a foot, which could damage the Thermal Protection System of the orbiter if it broke off and went skidding down the protection tiles or thermal blankets in the aft portion of the orbiter, especially around the aft engine compartments. Such damage to the TPS would risk burn-through of the aluminum skin of the side walls of the orbiter. The sun exposure of the liquid vents requires a mimum twenty minutes to assure melting of the "icecicles." However, most of the melting occurs primarily at the metal seal while the main portion of the icecicle remains intact.

reply to post by Truth1000


Ok, you answered the first 3 questions nicely, and the thread mentioned above also informed me that some astronauts did get sick apparently from the exposure to radiation.

Ice crystals initially remain ice crystals because of the extremely low pressure and very cold temperatures of space. Prior to entry, they do turn the left side of the orbiter toward the sun to melt any "waste ice" that may have formed from the liquid evacuation vent from the toilet. The crystals from the toilet have been known to reach sizes up to a foot, which could damage the Thermal Protection System of the orbiter if it broke off and went skidding down the protection tiles or thermal blankets in the aft portion of the orbiter, especially around the aft engine compartments. Such damage to the TPS would risk burn-through of the aluminum skin of the side walls of the orbiter. The sun exposure of the liquid vents requires a mimum twenty minutes to assure melting of the "icecicles." However, most of the melting occurs primarily at the metal seal while the main portion of the icecicle remains intact.

This still isn't making sense, because we are talking about the extremely small ice-particles that float right near the camera, and I've seen them remain in view for several minutes. There's no way in my mind that they would last so long. And there is no visible evidence that they are melting, as they don't appear to grow smaller.

I believe I understand what you are talking about now.

First, space is NOT empty. Even on the first Atlas/Mercury missions (with John Glenn aboard) he described particles that surrounded his vehicle.

Second, if you are actually talking about the particles I believe you are referring to, the reason they do not melt is because they are not ice particles. Soviet/Russian missions have encountered the same particles. There are news articles from NASA, PRAVDA, and both Space Agencies that have been released about these particles and I would refer you to them. They say all that can be said on a forum of this nature.

The reason the ice crystals dont "melt" is that they are reflective enough to not absorb enough infrared radiation to melt. They will eventually sublime away, due to the lack of pressure, converting directly to a gaseous state from a solid and forgoing a transition to the liquid state.
Now I know some will ask why then do the crystals melt off of the shuttle itself.
The shuttle absorbs infrared radiation and the warm surface melts the crystals away.

Originally posted by WhizPhiz
There are several things about space travel that I've always wondered about. Things that just don't seem to make any logical sense. I'm beginning to think we never did really go to the moon.

Howdy WhizPhiz!
I see you've been kind of impatient for answers. Actually, you posted in the middle of the night for a lot of ATS members who live in the US, so sorry if I'm late to the party.

You said that, "things... just don't seem to make any logical sense." The problem is that each of your questions are based on assumptions that may not be correct.

1) Did the first space suits really have no protection from radiation?

How much radiation were the astronauts expected to encounter? What types of radiation? What kind of materials protects against those types of radiation? How much of that material was needed to protect against the measured radiation levels?

When space radiation was discovered in 1958, We new that some protection would be needed. All of the above questions were asked and studied very carefully. Several countries launched probes to map and measure the radiation. The US sent more than 40 such probes & missions during the 60's.

To answer your question, early spacesuits did have some protection. However, spacesuits today do not have appreciably more radiation shielding than they did 40 years ago. That's because the average cumulative radiation dose for the few hours that astronauts spend outside is simply not enough to warrant further protection. If a transient event (solar flares or CMEs aimed in our direction) causes the radiation to increase above certain levels, then the astronauts get inside. If the radiation event is severe enough, the mission would return to Earth by the fastest means available.

There are two important things to remember:

First, radiation is not some monstrous all-killing furnace. It's kind of like the weather. Weather can kill you (tornadoes, baseball-sized hail, heat-stroke, etc.), but it is also predictable (at least, in the near term) - not perfectly, but well enough to decide whether or not tomorrow is a good day for a picnic. Most of the time, if you stay alert and take reasonable precautions, then the weather won't be a problem.

That does not mean that weather is never a problem, or that it can be ignored when making plans.

Radiation can kill you (by short exposures to high levels from a flare, or through prolonged exposure to low levels - the latter is why manned missions do not linger in the Van Allen Belts. The Apollo missions traversed the belts in less than an hour), but it is also predictable (at least, in the near term) - not perfectly, but well enough to decide whether or not the next two weeks are OK for a moon mission. Most of the time, if you stay alert and take reasonable precautions, then radiation won't be a problem.

That does not mean that radiation is never a problem, or that it can be ignored when designing spacecraft or flying missions.

Secondly, understand that it is very difficult to protect against worse-case scenarios, so a lot of the time they didn't even try. To use the weather analogy again, tornadoes have winds exceeding 300mph. Each year there are hundreds of tornadoes in the central US. Yet very few people (myself included) have houses built to withstand 300mph winds. We could, but it would be prohibitively expensive, and the odds are against my house getting hit by a tornado while I live here (knock on wood). In essence, I am gambling my life, the lives of my wife & kids, and all of my worldly belongings on the odds of not getting hit. It sounds reckless when I put in in those terms, doesn't it? Yet hundreds of millions of others take the same risk.

Similarly, those who designed spacecraft and planned manned moon missions in the '60s (and I include the Russians in that group) knew they couldn't shield against everything, so they studied the space environment, determined typical conditions and designed their spacecraft (and spacesuits) for that. They also looked at the average interval between dangerous events, and planned missions that were significantly shorter than that interval. For example, here is a Russian paper summarizing the the ability of men to survive a manned Zond circumlunar mission. The conclusion reads,

"The comparisson of the dosage evauations with the permissible values allows the conclusion that, should no solar flare occurs [sic], seven-day flights along the trajectories of Zond-5 and 7 probes are safe from the radiation point of view."

Yes, they were playing the odds, and the astronauts were gambling with their lives. However, they knew that the odds were in their favor, and hey, for the chance to go to the moon, would you take the bet? I would - in a heartbeat!

I hope this helps. I've got to go. I'll try to answer your other questions tomorrow.

Originally posted by WhizPhiz
2) Why did the Lunar Module clearly not leave a blast crater?

You weren't the only one surprised by that. Neil Armstrong commented on it just shortly after he stepped off the LM:

109:23:38 Armstrong: I'm at the foot of the ladder. The LM footpads are only depressed in the surface about 1 or 2 inches, although the surface appears to be very, very fine grained, as you get close to it. It's almost like a powder. (The) ground mass is very fine. (Pause)

109:24:13 Armstrong: I'm going to step off the LM now. (Long Pause)

109:24:48 Armstrong: That's one small step for (a) man; one giant leap for mankind. (Long Pause)

109:25:08 Armstrong: Yes, the surface is fine and powdery. I can kick it up loosely with my toe. It does adhere in fine layers, like powdered charcoal, to the sole and sides of my boots. I only go in a small fraction of an inch, maybe an eighth of an inch, but I can see the footprints of my boots and the treads in the fine, sandy particles.

109:25:30 McCandless: Neil, this is Houston. We're copying. (Long Pause)

109:25:45 Armstrong: There seems to be no difficulty in moving around - as we suspected. It's even perhaps easier than the simulations of one-sixth g that we performed in the various simulations on the ground. It's absolutely no trouble to walk around. (Pause)

[109:26:16 Armstrong: Okay. The descent engine did not leave a crater of any size. It has about 1 foot clearance on the ground. We're essentially on a very level place here. I can see some evidence of rays emanating from the descent engine, but a very insignificant amount.

Transcript, Video

Neil later took photographs of the affected areas under the LM. AS11-40-5918 (HiRes), AS11-40-5920 (HiRes) and AS11-40-5921 (HiRes) clearly show the "blown" look of the lunar dust under the LM, as opposed to the look of the soil some distance from the LM (AS11-40-5947 (HiRes)).

We knew from Surveyor photographs that the lunar surface was dusty, but we didn't know how deep it was. At Tranquility Base, Armstrong & Aldrin found that the loose dust was ~6 - 9 inches deep, and beneath it the surface was hard-packed and difficult to penetrate (This had unexpected reprecussions: When they planted the flag, the astronauts pushed the pole into the as best they could with their hands, but it was still unsteady. When the Eagle took-off, the blast from the ascent engine knocked it over. Apollo 12 hammered their flagpole into the ground further from the LM, but the crossbar wouldn't latch, and so the flag hung limply. Apollo 14 hammered it in well enough to withstand the blast from liftoff.). Subsequent missions found deeper dust, especially on the slopes of large craters and near the base of mountains.

So, the Lunar Module descended towards the surface, slowed by the Descent Propulsion System. The DPS rocket had a max thrust of 10,000 lbs, but as the Eagle hovered above the surface, it was throttled-back to ~3,000 lbs - you don't park your car with the accellerator floored (Note that, by comparison, a Harrier II jump jet uses a downward thrust of ~20,000 lbs to take-off vertically, and it does not dig a big crater). The rocket's nozzle was ~56 inches in diameter (source), so that gave it an area of ~2463 square inches (Area = pi * r^2). 3,000 lbs divided by 2463 square inches gives us a pressure of 1.2 pounds per square inch at the nozzle. In vacuum, the exhaust plume speads out rapidly (as discussed and shown in this recent ATS thread), so while the LM was still several feet up the surface pressure was much less than 1 psi. Still, that was enough to send dust flying - in vacuum it did not billow - as shown in the 16mm landing movies:

Apollo 11 powered descent & landing 16 minutes, 15.7MB I'm not going to apologize for the length or size. I still find myself holding my breath near the end, when the CapCom is calling out "60 seconds" of fuel left, then "30 seconds".
Apollo 12 descent from 19,000 ft & landing 5 minutes 10MB Intrepid landed near a large crater, and the blowing dust created zero-visibility at landing.
Apollo 14 descent from just before pitchover to landing. 6 minutes 16MB Another close-one where they landed with less than 60 seconds of fuel.
Apollo 15 2 minutes, 37 seconds 20MB I love the view of Hadley Rille in the distance!
Apollo 16 5 minutes 8.7MB About half-way through you can see the shadow of the descending LM in the distance, giving you a sense of scale which was often difficult to come by on the unfamiliar lunar surface.
Apollo 17 3 minutes 32 seconds 5MB. The Lunar Module Challenger landed in a valley surrounded by dramatic mountains.

The DPS blew away much of the dust, giving the ground its flattened & scoured appearance. Note that Neil said his boot only sank into the dust "maybe an eighth of an inch" next to the LM (as seen in AS11-40-5917 (HiRes)). Further away, their boots left deeper prints AS11-40-5943 (HiRes)).

Hope this helps.