Orion!

Jun. 28th, 2011 01:28 am
scott_sanford: (Default)
I know this will be of interest to some of my readers. Back in 1959 the Orion project was still getting funding (sanity had not yet set in) and some actual flight tests were done. This short video clip shows an unmanned 105kg test vehicle taking off propelled by 1kg C4 charges.

(Related only by reader interest, it seems that Los Alamos has a large wildfire.)
scott_sanford: (Default)
According to this article the structure of the outer heliosphere is more complex than anyone suspected. (You know, before we shot the Voyager probes into it.) There doesn't seem to be any horrifying doom implied by large frothy magnetic field bubbles a hundred AU from home, but no doubt some author will do something with them.
scott_sanford: (Default)
Over on Rocketpunk Manifesto I ran into this comparison:

The downgrading of the Shuttle program thus turned out to be part of a larger political shift, which has affected American space activity ever since. NASA had, and retains, a sufficient base of public and interest-group support that, like Amtrak, it could never be eliminated outright, but it has been kept on a sort of starvation diet, the root cause of many of its failings. If you provide just enough funding to keep a program from dying outright, you keep it alive but ensure that it will be suboptimal.

True enough, and some Americans are fans of both. There doesn't seem to be any good way to get more funding into either, although if you chat up a supporter you can hear of many useful things that could be done if the budget weren't so painfully restricted.

I think our priorities are not those of most folks.
scott_sanford: (Default)
The exoplanet WASP-18b is gifted with a few quirks, like 3800F daytime temperatures and an 22.5 hour year, but they pale beside the fact that it's de-orbiting and will soon hit the Roche limit and break up, after which the bits will fall into the sun. One thing about astronomy, there's always someplace that makes even the less favored parts of Earth look good.
scott_sanford: (Default)
So I'm wasting time on the net as usual when I run across an anecdote from Operation Plumbob, a nuke testing program back in the 1950s.

It seems that their point criticality tests led to some interesting learning experiences. Follow along: Pascal-A was supposed to check that a single faulty detonator could not actually set off the whole bomb (an implosion type design counts on having a bunch of carefully timed detonators to, well, implode). So the test unit is lowered down a 147 meter shaft and set off, which is when they discover that someone's slipped a decimal point somewhere - the yield is about 55 tons, or 50,000 times what they expected. Oops.

Witness Robert Campbell said, "Biggest damn Roman candle you ever saw! It was beautiful. Big blue glow in the sky..."

Right. After this little learning experience, they redesigned things a bit for the next test.

Pascal-B was a near duplicate of Pascal-A, but after the fireworks display last time, the scientists decided to put a cap on the hole. (The military has a very good understanding of "tube with explosives at one end.") Starting with a piece of four inch thick armor plate, a one-ton steel cap for the hole was made and lowered into place for the test.

Like the first time, this test was predicted to yield about as much force as 1-2lbs worth of TNT. Like the first time, this wasn't particularly accurate. Pascal-B went off at around 1/3 kiloton, or 600,000 times what it should have. Oops, again.

The surface high-speed camera caught exactly one frame of that one-ton steel plate as it left the ground, headed upwards at what was later estimated as six times Earth escape velocity, never to be seen again. A flying manhole cover moving face-on through the air is a spectacularly un-aerodynamic shape, and the best guess is that it vaporized long before it left the atmosphere.

While the cap was very, very gone it was not forgotten; this incident was brought up later in connection with the Project Orion concept. There's probably a moral in there somewhere.
scott_sanford: (Default)
Among [livejournal.com profile] james_nicoll's verbose postage was a link to a space warfare essay, Battle of the Spherical War Cows: Purple vs. Green. Well! How can you pass up a title like that?

But from there we link to the Atomic Rockets site, with...even more essays! I am doomed! DOOOOMED!
scott_sanford: (Default)
I see that Neal Stephenson has things to say on Slate, the gist of which is (a) rockets are expensive and (b) changing the game is hard. Naturally he says this in more detail than I do, and I was tickled to see him mention Jordin Kare.
scott_sanford: (Default)
        PROLOGUE
    Recently, in the interests of fair play and open discussion of views, I agreed to watch a presentation of an opinion with which I disagreed.  The friend with whom I was talking chose 'A Funny Thing Happened on the Way to the Moon' by Bart Sibrel, which proposes that the Apollo moon landings were faked.
    I had a few hopes that it would provide some food for thought.  As food goes, this is cotton candy, and possibly cabbage flavored.  It did send me to the net for something more substantial, though.  Let's begin.


        THE VIDEO
    The video opens with assorted quotations and a long rambling monologue, eventually getting around to the subject of space exploration.  About six minutes in we move over to a montage of rocketry disasters which brings us to 8:20.  About ten minutes into the video we finally see an Apollo liftoff, and at 12:25 it finally makes a verifiable claim.
    Thirteen minutes in the film finally starts making factual claims.  Here are three claims:
    1) Traversing the Van Allen belt would take 90 minutes: true.
    2) Solid lead shielding would been needed to let humans survive: plausible but not supported by available information.  A quick google turns up the radiation exposure numbers; Apollo 11 had the second from lowest radiation dose average at .18 rads, the highest being the Apollo 14 crew at 1.14 rads.  (Apollo 9 never left Earth orbit and avoided the van Allen belts entirely, but still averaged .2 rads, slightly more than the Apollo 11 crew.)  As a comparison, nuclear industry workers are allowed a maximum of five rads per year by the AEC.  Too, cosmic background radiation seems to be agreed to have contributed more than the brief Van Allen belt pass.  The radiation exposure wasn't good for them, but it was quite survivable.
    3) The Saturn V was 35 stories tall and weighed as much as a battleship: Mixed truth.  The listed height is 363ft, so the height claim can be called true.  Fueled it weighed 6,699,000lbs, 3349.5 tons vs 10,288 tons for the USS Oregon (BB-3), a particularly wimpy battleship, or HMS Dreadnought at 18,120 tons; the weight claim is false.
    So far we're batting .500; enjoy it while you can, because that's as good as it gets.
    It goes on to talk about the Van Allen belts and make vague claims about their intensity.  (Whoever did the CGI did their research; you can see the inner and outer bands.  That's not hard to do, but there's much wrong here that I think it's worth pointing out when something is gotten right.)  The narrator talks about radiation induced visual effects, which is true.  (I've heard this is from nervous tissue impacts not retina interaction - verification, anyone?).  The narrator only talks about shuttle reports, but the effect was reported as far back as the Apollo missions.  Saying that would be harmful to their premise, however.  Also, someone should have clarified the use of 'electrons' as a generic synonym for 'charged particles.'
    Then it wanders away into conspiracy theory stuff - we still have Kennedy assassination theories, so therefore...um, something.  In passing it mentions that the Soviets were first to put an animal in space but shows a monkey rather than Laika, which shouldn't have been done once much less twice.
    At 21 minutes in we get back on track and it claims a satellite called Tetra (perhaps?) was launched in 1968 to test and train ground crew.  I hadn't remembered this, but sounds practical.  However, goggling doesn't turn it up.  (I'm not saying it didn't exist, just that google, wikipedia, and nasa.gov are silent about it.)  This falls apart when they hint it could be used to fool the Soviets that radio signals were coming from orbit not the moon.
    One quote caught my attention enough to transcribe.  At 22:20 the narrator says, "Whatever pictures and sound were distributed were strictly controlled, and previewed by the federal government."  Did the scriptwriter not remember that this was going out on live television?  Is the audience not supposed to remember that?  If you're going to contradict something widely believed and personally witnessed by hundreds of millions of people, you really shouldn't just throw out a dubious claim and move on.
    Never mind; 23 minutes in it claims fewer than 20 pictures from the time Apollo 11 actually spent on the moon.  This is incorrect; see http://history.nasa.gov/alsj/a11/images11.html for a really huge collection.  Many of them are not interesting - for example, film magazine #45 alone has 35 shots - but it was used in the Lunar Surface Closeup Camera and so has only pictures of rocks - but they exist and are available on the internet if you're into that.
    At 23:45 it claims that there is only one full body picture of Neil Armstrong on the moon.  It's unclear why a 'full body' photo would be particularly interesting, but it's true Armstrong did a lot of photography so we've got many pictures of Aldrin.
    It goes on like that for a while.
    Eventually they get around to pointing out features of the lunar photographs, most of which have been debunked so many times it annoys me that this still gets trotted out.  The site badastonomy.com sends up science errors on TV, and you can read them ripping into the Fox network's moon hoax special at http://www.badastronomy.com/bad/tv/foxapollo.html - that program and this repeat each other's errors; users of tvtropes.com would say You Fail Photography Forever.
    There is a new thing that I hadn't seen debunked before this week, a rock that supposedly was seen with a letter C on it - and in other copies of the photo without the mark.  A little googling turns up clearer images and the claim from actual photographers that the curl is a hair or fiber on the processing equipment.  Sorry, moon hoaxers, you've got a good question there but the answer isn't convincing.
    You can see the rock (without mysterious marks) at http://history.nasa.gov/alsj/a16/AS16-107-17445.jpg and http://history.nasa.gov/alsj/a16/AS16-107-17446.jpg - the antenna shadow ends at the rock in question.  By the way, that shadow is explained as a cleft in the paper mache rock by some hoaxers; did they both not bother to look at the original photo and not think NASA could afford real rocks?  Anyhow, the page at http://www.informantnews.org/modules.php?name=Content&pa=showpage&pid=27 examines the C rock issue in detail.
    My notes read '31:00 If you're going to be making a big deal about flags 'waving in the wind' you should probably keep the footage with a flag clearly not moving at all farther away.'  Yeah...  The video made a great deal out of waving flags, while showing them in motion as astronauts fiddled with them.  Only a few minutes later it was questioning the astronauts' style of walking on the moon but used footage showing a completely motionless flag in the background.  Oops.
    Things get interesting at 37:00.  Some time is spent with the narrator saying things but showing a rather basic view of the Earth from space.  This is supposedly faked...but it's unclear what fakery we're supposed to be seeing.  The 'mistake' at 38:50 looks a lot like the edge of a window.  I don't know what the 'crescent insert' at 39:26 is supposed to be, but something gets in the way of the camera at that point; nothing particularly shocking happens.  The camera setting change around 39:40-39:47 is interesting; after the adjustment of the camera and return of interior illumination there's quite a lot of illumination seen briefly out the window.  I'm not sure what that glare means, as the angle is wrong for sunlight; it might be reflection from the interior lights (we don't see it until the crew turns on the inside lights).  The documentary claims it's Earth, much closer than it should be - and cuts away just as something interesting is seen.  This is frustrating, but unfortunately typical.
    That's the last meaningful claim of the video, although the narration goes on for a while.

        AFTERTHOUGHTS
    The program's basic premise, that Apollo 11 never left orbit, is unfortunately the least plausible model for faking a lunar mission.  The Soviets were tracking it on radar.  Various nations, some not friendly to us, listened to the Apollo radio signals. Individual amateur astronomers worldwide watched and tracked the spacecraft visually (cf 'Optical Observations of Apollo 8,' Sky & Telescope magazine, March 1969).  The retro-reflectors set up by Apollo are still in use.
    As an aside, it's occasionally brought up that the Soviets didn't have good deep-space radar to observe things going on near the moon until the 1970s, after the Apollo missions ended.  This is technically true, but in the 1960s they were very interested in tracking satellites and rockets.  They had no intention of letting a rocket leave American territory without them knowing about it, and many systems useful for tracking ICBMs work well on satellites too.  Their Luna 15 probe is never mentioned in this film and would only complicate matters - it orbited the moon at the same time Apollo 11 did, was designed for sample return, and might well have actually beaten them back to Earth had it not crashed in Mare Crisium.
    It's unclear whether the audience is supposed to believe that the Soviets thought a manned mission to the moon was impossible to survive due to radiation, or if the Apollo missions were faked to make the Soviets think we'd done it; the video makes both claims several times, apparently without noticing that they contradict each other.
    If one wishes to argue for a faked moon landing, I think there are only two plausible models for astronaut location during the mission.  Either they were aboard and circled the moon without landing (as Apollo 8 and 10 did), or they never left Earth at all.  After considering the logistical problems of getting them back into a command module to be picked up by the Navy on time, I think actually sending them around the moon would be easier.  However, advocating this would require hoaxers to back off from the Van Allen belt radiation story, and this seems unlikely.
    All in all, this is not a very good presentation of a claim.  (It can't really be called a theory, or even a hypothesis.)  When offering a view contrary to expectations, you should carefully craft your arguments, and have information supporting your model; asking vague questions and making vague appeals to paranoia are not useful tactics in an intellectual debate.  Bart Sibrel failed to support his claims in this piece, and moreover left me confused about why he believed them.
    I'll finish this by leaving you with two quotes:

    "Now let me correct you on a couple of things, OK? Aristotle was not Belgian. The central message of Buddhism is not 'Every man for himself.' And the London Underground is not a political movement. Those are all mistakes, Otto! I looked them up!"  — Wanda, A Fish Called Wanda

    "Other people have watched it so you don't have to."  - Guy Letourneau


References and useful reading

http://history.nasa.gov/alsj/
    Apollo Lunar Surface Journal
http://www.apolloarchive.com/apollo_gallery.html
    Even more photos
http://lsda.jsc.nasa.gov/books/apollo/S2ch3.htm
    Biomedical Results of Apollo - Radiation Protection and Instrumentation (just as dry a read as the title suggests, but informative)
http://en.wikipedia.org/wiki/Van_Allen_radiation_belt
    More readable than the above, and addressing the physics angle
http://www.astr.ua.edu/keel/space/apollo.html
    Visual tracking of space vehicles
http://www.badastronomy.com/bad/tv/foxapollo.html
    The Fox special "Conspiracy Theory: Did We Land on the Moon?" taken apart with a blunt axe.
http://www.badastronomy.com/bad/misc/apollohoax.html
    A list of websites addressing the issue
http://www.clavius.org/
    A website with even more debunking
http://www.madsci.org/posts/archives/may2000/959341359.As.r.html
    Radiation addressed yet again, only interesting because the author says he personally observed Apollo 8's Trans-Lunar Injection burn.
http://www.jaxa.jp/press/2008/05/20080520_kaguya_e.html
    Views of Apollo sites used to check accuracy of Japanese lunar mapping
http://www.newschannel5.com/story/10799169/inside-story-apollo-conspiracy-theorist-arrested-after-tirade?nav=menu374_2_11&redirected=true
    Irrelevant to the debate, but includes a photo of Bart Sibrel
http://www.informantnews.org/modules.php?name=Content&pa=showpage&pid=27
    The 'Letter C' rock, mysteries solved with a little footwork
http://www.amazon.com/Funny-Thing-Happened-Moon-moonmovie-com/dp/B000059MCV/ref=sr_1_1?ie=UTF8&qid=1291449183&sr=8-1
    The amazon.com page for this video; many of the reviewers are less charitable about it than I am

Mythbusters episode S6E10
    A vastly better researched program than what I watched tonight - and they got to play with toys
http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceDoesNotWorkThatWay
    Not in any way connected to the moon hoaxers - but an entertaining collection of goofs just as bad as in this video

Profile

scott_sanford: (Default)
scott_sanford

April 2017

S M T W T F S
      1
2345678
9 101112131415
16171819202122
23242526272829
30      

Syndicate

RSS Atom

Most Popular Tags

Style Credit

Expand Cut Tags

No cut tags
Page generated Jul. 22nd, 2017 10:55 pm
Powered by Dreamwidth Studios