Jan 31 2008
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50 years after Explorer 1
Today marks the 50th anniversary of the launch of America’s first satellite, Explorer 1.
This was a response to Sputnik, launched by Soviets a few months before. The whole story is actually a bit complicated (Clavius.org has a nice synopsis, and AstroProf has more too); but ironically the Americans could have had the first satellite in orbit had they not been reluctant to use a rocket built for the Army and based on German technology.
Explorer 1 was equipped with an X-ray detector that was basically a fancy Geiger counter. Built by a team led by James van Allen, it was lofted up to see what the radiation environment of space was. The team was astonished to discover that near-Earth space was tremendously radioactive; their detector saturated.
And thus the basis of the Moon Hoax was born.
Too bad; if the hoax believers had some basic science education they’d understand the problem. What Explorer 1 discovered were the van Allen radiation belts: regions around the Earth where the magnetic field of our planet has captured subatomic particles. Moving at high speed, when these slam into the metal walls of a satellite they are decelerated. This process produces X-rays (called Bremsstrahlung — German for "braking" — radiation), and that’s what the Explorer 1 detector detected. Moon hoaxers get terribly confused about this, saying there are deadly X-rays in space. They’re wrong: the X-rays are a by-product of the subatomic particles screeching to a halt inside metal. Unless the Sun is flaring, there is very little X-radiation in near-Earth orbit. It’s the subatomic particles that are dangerous, but they can be stopped by various substances like glass and insulation without creating X-rays.
Try explaining that the hoax believers. You might as well speak in Klingon to them.
Anyway, Explorer 1 was a fantastic achievement. Not only was it the US’s first satellite, it also broke through a new frontier in science. We learned that the Earth’s magnetic field has ramifications for space flight, and eventually led to a better understanding of how we are coupled with our nearest star, the Sun.
Mind you, these guys had no clue what they’d find. That’s why they put the X-ray detector in Explorer 1 in the first place! And look what happened.
I salute the pioneers of the space age, and of the space science age. We owe you folks a lot.
I’ve noticed a similarity between Fundamentalists/Creationists and Hoaxers/Truthers:
It seems that the groups mentioned above have a hard time understanding that science is a process and not a doctrine, belief or “text”. Science is a tool you use to find out about the world around you and it is an ongoing process.
Why is it so difficult to understand that refinements in technology and the greater knowledge we gather with these refinements will, over time, expand our understanding of the universe and that old theories may, at times, fall by the wayside, but that our understanding of the fundamental processes that define the basis of scientific knowledge are strengthened by this “weeding out” process?
It’s really sad ;)) that the Russian failed to notice the Van Allen belts… after 2 Sputnik launches… ok Sputnik 1 was merely an radio in space, but Sputnik 2 had radiation detectors on bord (besides the headline grabbing Laika)…
And what about the ATV… it seems they will go for launch at the end of February the beginning of March.
Guess they are waiting for… USA-193 :D.
@Kate:
It is the only kind of worldview some people understand, particularly those with control issues. They need a firm etiology, and since science can’t provide one they either adopt one or create one. It’s the very fluidity of scientific explanation that makes it unpalatable. It is much more comforting to say “X knows” or “I know” rather than “we don’t know.”
Attributing purpose and cause is a normal human response: it’s how we learn correct social behavior through punishment and reward. Punishment is a dominance behavior, and because of this it is in our behavior to assume a punisher, or dominant individual, for events that are adverse.
Assuming an event is simply chance or accident is a behavior that is not very natural. Ignoring a “warning” from a dominant individual is antisocial. So, assuming an event is random and otherwise simply coincidence is an abberant, antisocial behavior.
Now does some of the vitriol make sense?
Hey Phil, aren’t you conflating radioactivity and electromagnetic radiation? The X-rays in space are caused by electromagnetic radiation. There aren’t particles up there in significant amounts, radioactive or otherwise. So I wouldn’t call it a glorified Geiger counter, because a Geiger counter is used for something else. This line in particular is very misleading:
“The team was astonished to discover that near-Earth space was tremendously radioactive.”
High-energy electromagnetic radiation is completely different from radioactivity, of course.
I watched the first Vanguard(attempted) when the grapefruit sized satellite ended up bouncing across the ground, beeping pitifully. It was a great crash, burn and explode scene. Warner Von Braun basically went before the Congress and said” I can put up a functional satellite within 60 days(later revised to 90 days)”. The Explorer 1 was actually launched 88 days after Von Brauns crew was given the go ahead. T’Was a marvelous achievement.
Had we followed the Von Braun plan, we’d have had an earth orbiting space station by the late ’60s and probably a permanent presence on the moon by the late ’70s but NOOO, we just had to one up the Soviets with a great rush to the moon, for no viable reason. How come politicians NEVER listen to reasonable people???
GAry 7
So your offhand reference to speaking Klingon brought this thought to mind — how much crossover do you think there is between Hoaxers and Star Trek fans? Are Hoaxers averse to science fiction and space travel stuff in particular because they think it’s impossible, or do they dispose of all their alleged critical thinking to enjoy Star Trek and such but then slam real-life space exploration as untenable?
Gagarin - first man in orbit??? Hmmm read those….
http://www.myhero.com/myhero/hero.asp?hero=Ilyushin
http://www.astronautix.com/astros/ilyushin.htm
Cyde: The term “radioactive” was coined by the French scientist Becquerel in 1896, to describe the phosphorescence effect induced by exposing photographic plates to X-rays(energetic electromagnetic energy) and uranium salts(energetic particle emitter). Thus the term radioactive applies to any high energy particle or electromagnetic wave.
There ARE tons of energetic particles trapped in the magnetic field lines surrounding earth(Alpha and Beta particles, iron nuclei, etc.) and when they strike metal, they radiate energetic electromagnetic waves(X-rays). The solution to traveling thru the Van Allen belts of trapped particles is to do so in containment that is easily penetrated by the particles, so that they pass right thru w/o interacting and producing x-rays.
That’s how we got our astronauts to the moon and back alive and (relatively) undamaged,,,
GAry 7
@Pat:
I hate to break it to you, Pat, but no matter how well you explain the motivations behind the behavior I’ll never understand it. (Yes, that’s meant as a joke.)
…but seriously… My question was more rhetorical than an honest quest for an answer to the question of why fundies, hoaxers, creationists and truthers are happier with lies and fairy tales than they are with an honest picture of how things are.
Um, Cyde - a Geiger counter works by converting a particle interaction with its intert gas detector to an electrical signal (alpha or beta particle). High energy electrons (beta particles) (as contained in part of the Van Allen belt) colliding with metal produce X-rays. This is how they are produced on earth; by colliding accelerated electrons with a metal target. Carbon nanotubes might allow us to produce them another way, but the bulk are electrons to metal target.
Clavius.org has updated a bunch of pictures and such since I first read it a long time ago. Excellent site.
@Kate
Okay : ) - I guess not everybody shares my genuine fascination with this phenomenon. I don’t attribute it to a weakness of character or a lack of intelligence. If anything, the reason it is so widespread is because it is a “normal” behavior, like hatred of the outsider, and it might be that the only way to counter it is to understand it in depth and where its source lies.
Education appears to be the only tonic that works to remedy this, so it would seem to be better to go after intolerance of education ahead of focusing on attacking logically weak accepted conventions. Currently, there is perceived nobility in lacking education, and this needs to be crushed rather deliberately. People once educated in critical thinking are much less vulnerable to fallacies of magical thinking.
Slightly OT, but related to the early space age…
The Mercury Seven all came out of the military test pilot programs. A reporter asked one of them (sadly, I forget which) what the difference between a regular pilot and a test pilot was.
The answer was something like:
“A regular pilot thinks ‘This plane’s gonna crash in ten seconds.’ A test pilot thinks ‘Hell, I’ve got ten seconds. I can save this thing.’”
GagarinNo, I have my doubts about the story, but I am sure there is much we don’t know about the Soviet Space program, and much more will be revealed, hopefully, as time goes on and documents are uncovered. If this is true, then it would only be fitting that Ilyushin gets the recognition that is due to him.
Phil, It’s good to know there are other explanations on this issue..I’ve never heard this particular explanation before on the x-ray’s caused by the VA belt are really a byproduct of human interference, that metal is the catalyst for causing the x-rays..
So, let me get this straight… the x-rays are “made” when particles in our magnetosphere decelerate in the metal…
Where do the x-rays then go after they are generated? Since the apollo was made mostly out of metal then it should have been saturated with particles… and surely you’re not claiming that the craft was thick enough to stop particles from travelling through the skin of the spacecraft?
A neat science experiment would be to take the capsule that was used, and do the tests to see if particles, x-rays, gamma rays etc.. would pass through the capsule. Take it one step futher and put a monkey, or dog in the capsule, and then expose the whole thing to comparable solar radiation…
Here’s an interesting note… look at what today’s satellites have for insulation against these phenomenon, and look at what the apollo craft had… notice anything missing from apollo?
Do the google on it phil… there might still be hope for your skeptical mind yet!
Cyde Weys posts:
[[Hey Phil, aren’t you conflating radioactivity and electromagnetic radiation? The X-rays in space are caused by electromagnetic radiation. There aren’t particles up there in significant amounts, radioactive or otherwise. So I wouldn’t call it a glorified Geiger counter, because a Geiger counter is used for something else. This line in particular is very misleading:
“The team was astonished to discover that near-Earth space was tremendously radioactive.”
High-energy electromagnetic radiation is completely different from radioactivity, of course.]]
No, Cyde, Phil was right and you are wrong. He was referring to subatomic particles, protons, neutrons, electrons. These are not “electromagnetic radiation.” And a Geiger counter would pick them up. Alpha rays are helium nuclei, beta rays are electrons. Only gamma rays are EM radiation, and they are rare in the sky, though there are some strong point sources here and there (e.g. the Gamma Ray Bursters). X-rays are EM radiation, but they are caused by the subatomic particles in the Van Allen belt striking metal and kicking up secondary radiation.
Okay okay, I yield. Thanks for the explanations guys.
Happy Anniversary, Explorer 1!
We’re come far, but the next fifty years will make today look just as primitive…
“What I to apeman?
And what then he to me?
I an apeman one day soon shall seem to be.”
-Ray Bradbury.
[…] steal something from elsewhere. I was reading the comments to the Bad Astronomy article on the 50th anniversary of the Explorer 1 satellite. Phil battles purveyors of crackpot ideas all the time, but especially those about space (killer […]
Nice write up on SpaceReview.Com about one of the team members from Explorer 1 - William Pickering. Kiwi legend and director of JPL from 1954 - 1976.
http://www.thespacereview.com/article/1044/1
The BA says: ” ironically the Americans could have had the first satellite in orbit had they not been reluctant to use a rocket built for the Army and based on German technology.”
It wasn’t just the reluctance to use German technology (actually I consider that a slam against the US scientists and engineers on the Juno and JPL teams), it was a fear of international repercussions. No one had legally established the upward extent of “airspace” over a nation. Since it is inevitable that a satellite will overfly every country with a latitude lower than the satellite’s orbital inclination, the was a considerable fear in the State Department that the Soviets could declare a US satellite flying over their “airspace” to be an invasion and an excuse for retaliation.
By letting them go first, the issue was rendered moot.
- Jack
I forgot to mention that the Nova on Sputnik last October (on its 50th) brought this out in very detailed fashion.
- Jack
If I remember right, the detector breaking down is what led them to believe that there was a Van Allen belt.
Happy Golden anniversary to the Explorer team.
I’ll answer to several posts at once.
First, Geiger counter CAN detect X-rays because the cause ionization (you know, X-rays are not called ‘ionizing radiation’ for nothing) which triggers the counter.
Second, X-ray range bremsstrahlung (braking radiation) is produced when a particle hits a heavy nucleus.
Imagine that a fast-moving particle is a fast-moving car - if you hit a wall then a driver without a seatbelt will be catapulted through the windshield. That’s also exactly what happens with particles.
However, if a car hit a series of cardboard crates - it will be safely slowed down to a halt. That’s also exactly the thing you want to do with particles.
So Apollo used radiation insulation made from polyethylene, which is made of light atoms (carbon and hydrogen) and doesn’t generate bremsstrahlung.
And no, that doesn’t mean that particles flew right through Apollo capsules. They were (mostly) absorbed in radiation insulation.
BTW, bremsstrahlung is used here on Earth to produce X-rays in X-ray machines in hospitals.
I find it ironic that they were reluctant to use rockets based on German technology, when in fact many of their rocket scientists were captured from Peenemunde. So, in essence, wasn’t their rocket technology based on German technology anyway?
Sorry for the d.p. Don’t hoaxers use the fact that astronauts have reported seeing “sparks” when they close their eyes to sleep? Correct me if I’m wrong, but aren’t those cosmic rays? I also understand that it does not pose the same danger as the type of radiation in the Van Allen belts. Hoaxers would have us believe otherwise. One other reason that the radiation didn’t pose much of a threat to the Apollo astronauts is that they simply were not there long enough. I believe they spent less than an hour traveling through that region on their way to the Moon.
Mike J:
Check Van Allen belts on Wikipedia. There are two belts, one extending from about 200 km to 1000 km: another extends from about 12000 to roughly 40000 miles. Travel above, below or between the belts is free of those trapped particles, with a consequent reduction in radiation intensity. Granted, long term(years) exposure to cosmic radiation would likely be deadly, which is one of the prime considerations for a MArs manned trip. Adequate shielding from cosmic rays would require a lot of matter but one analyses I’ve seen says it’s only necessary to have about three meters of shielding, presumably something rich in carbon, which slows the incoming particles and sequesters them.
One of the entrepreneurs trying to build a guest hotel space module uses polyethelene as the shielding,,,
Gary7
Michael Lonergan says: “I find it ironic that they were reluctant to use rockets based on German technology, when in fact many of their rocket scientists were captured from Peenemunde. So, in essence, wasn’t their rocket technology based on German technology anyway?”
That’s exactly what Phil meant by “German Technology”. See my post about a screen back.
- Jack
Phil,
Strictly speaking, Geiger counters aren’t “X-ray detectors.” They detect ionizing radiation, of which X-rays are just one type.
More details over on my site,
Sam
Explorer 1 at 50…
50 years ago today, at 10:48 pm Eastern Standard Time on January 31, 1958, the U.S.’ first satellite was launched. Some items seem to escape mention in many discussions of the event, so let’s talk a bit about the “forgotten history” of Explorer 1…..
Early saturday morning, January 30, 1957. I’m eight years old, and I go to the living room to watch caroons on a program hosted by Ray Rayner in Chicago. He comes on and says, “Kids, something very exciting happened last night. The United States launched its first earth satellite. It’s called Explorer….” I ran into my folks room and woke them up, shouting “WE LAUNCHED A SATELLITE!!” I still have the newspaper clippings, somewhere.
My father worked on Explorer 1. He started working at JPL the day after he graduated from Caltech, tested missiles at White Sands for Von Braun, and designed the microwave transmitter for Explorer 1.
Dad told a story recently that I hadn’t heard before; it came up when James Van Allen died not so long ago. He said that he and Dr. Pickering, director of JPL, went together to talk Van Allen into putting an experiment on the satellite, which of course resulted in the discovery of the famous Van Allen radiation belts.
So thanks for the recognition of my Dad as a space-age pioneer!
Mike J. said:
“look at what today’s satellites have for insulation against these phenomenon, and look at what the apollo craft had… notice anything missing from apollo?”
If what you’re referring to is that gold-colored crinkly foil, then it’s irrelevant to to the issue of ionizing radiation. That gold foil is some stuff called “Kapton”, and is for reflecting a broad band of infrared light. It’s heat protection. The Apollo command module had its own variety of such protection. It was a smooth layer of highly silvered mylar, applied in adhesive strips. If you look at pics of the CM/SM taken from the LM, the CM looks very silvery, even mirrored. That’s what it looked like before plowing back through the atmosphere during re-entry.
Hi Jack (I’ve always wanted to say that… on a plane though
) I was trying to say that, or ask, maybe, wouldn’t all of US rocket technology, and even Russian for that matter, because I understand they also took some rocket scientists as well, have some basis in German technology?
[…] Bad Astronomy Blog has some of the story, and of course Wikipedia reveals […]
Michael Lonergan says: “Hi Jack (I’ve always wanted to say that… on a plane though )
Gee, I’ve never heard that joke…
> I was trying to say that, or ask, maybe, wouldn’t all of US
> rocket technology, and even Russian for that matter, because
> I understand they also took some rocket scientists as well, have
> some basis in German technology?
You are correct for many early vehicles. The US got most of the German design team and their tons (tonnes?) of documentation. The Soviets got most of the unassembled hardware and production equipment left at the Nordhausen “Mittelwerk” assembly area.
If you look at Korolev’s first large rockets after the war, they are direct V2 copies with some bizarre appendages. The SCUD missile is a very close descendant of the V2, with the only significant changes being the shape (to make it easier to manufacture) and changing the fuel from alcohol to kerosene (that’s “paraffin” to you Brits). The thrust chambers were adapted for cluster use in the R7 ICBM, which launched Sputnik, Vostok, Voskhod and Soyuz. The booster (the classic one with the central core and four tapering strap-on’s) is still in use today for all of their manned and most unmanned launches. It is the most successful space launch vehicle every built, and is only one generation removed from the V2.
On the US side, the Redstone missile was von Braun’s “US V2.” It was a direct copy, technologically, including the use of alcohol fuel. Like the SCUD, the shape was simplified for manufacturing. The big changes were in the control system and in the development of a detachable warhead. This is the booster that put Alan Shepard and Gus Grissom into sub-orbit.
Moving on, the Juno (the name of the booster that launched Explorer) moved up to kerosene fuel and other advances. However, that’s where the direct V2 line sort of fizzles out in the US. True, the majority of the design staff at Huntsville (later NASA Marshall) were Peenemunde alumni, but they went new directions. The last gasp of the Third Reich in the US space program was probably the Saturn 1. They wanted to use proven hardware to scale up the boosters quickly. Traveling the same path as Korolev, they lashed 8 Redstone tanks around a central core tank and put 8 large combustion chambers under them. It was derided as “Cluster’s Last Stand” by critics, but it’s the booster that lofted Apollos 7 and 9 into orbit.
If you look at the family tree of US launch vehicles, though, most of the designs today can trace their ancestry back to the Viking sounding rocket of the early post-war period; a design that owes nothing to the Germans.
- Jack
According to a PBS special the Van Alan
belts were not discovered by Explorer but
by a balloon experiment. The Explorer series were really spy satellites, that were given a science satellite cover story.
One reason that the US acted slowly was that Eisenhower, who badly wanted a spy satellite, was unsure of the international law reaction to a satellite going over borders. But, sputnik solved that problem for him.
The real reason that Sputnik was so scary was that Doppler shift from its radio transmitter allowed the Russians to get
a good enough measurement of the earth’s
non-uniform gravity field to get FIRST STRIKE capacity, by getting ICBM’s ( that
B is for ballistic) close enough to destroy our missile launch sites.
Penny
The first american satellite program was
Vanguard. It was not a crash project–while Eisenhower dithered over the implications for war.
But, they did get some satellite launches ready–after Sputnik was already in orbit.
They failed because the boosters went rapidly off course and had to be destroyed.
Why? Because the navigational algorithm needed the inverse of a matrix, and some engineer didn’t understand what that meant–so he entered the multiplicative inverse of each term in the matrix!!
It was embarassing as we televised the launches. That was when, Von Braun
( the Nazi Mass Murdering SS war criminal, who we paperclipped into a national hero)
was given his chance.
Penny
It is a shame that we went with the German monsters for our space program when we could have used Ted Von Karman of Caltech, Robert Goddard, and Jack Parsons.
Alex,
Gee, I haven’t heard the term
bremsstrahlung in thirty years. It is usually called the Compton Effect ( Or Compton Scattering) in America. The particle doesn’t even have to hit the nucleus, it can scatter nearby and lose energy in the form of X-Rays or even Gamma rays. There is also a reverse process called the Inverse Compton Effect where particles can be created from the vacuum this way.
Barton, this is high school physics! Or it was back in the sixties, when I went to High School.
Penny
Alex,
Speaking of German terms, do you recall
Bremenschloss? This was a term used in
“Rockets, Missiles and Space Travel” by Ley and Von Braun, which I owned as a child.
Bremstrallung is very pretty, but my favorite is Zitterbewegnung, which you probably also know.
Die Deutsche Sprache sind viel schone fur Naturalwissenshaft.
Penny
Jack,
I missed your post about the Nova episode or my post could have been shorter!
Penny
One poster suggested that we could have had a space station had we followed VON Braun–but why would that have been important?
The main reason for a space station was to do what unmanned satellites do–before we had transistor circuits. Someone had to be up there to change the tubes!!
Space stations are scientifically worthless.
Our current one is a huge boondoggle–as the National Academy of Science has assured us again and again.
And, what exactly is the advantage of building a space ship piece by piece up in space at the space station? You still have to drag the parts up there–and the fuel too.
One could do that –if one wishes too–with the shuttle.
I suspect that Von Braun got his idea on building a space station back in the forties
before transistor circuits and it became an obsession.
It was an old science fiction trope–dating back to “The Brick Moon” by Nathan Hale!!
( which you can find on the net). There, of course, there was no electronics and humans were needed. They were to send messages via heliostat.
Penny
A correction:
It seems that Bremstrallung is used to denote x-rays from electrons scattering near a nucleus, and the inverse
Compton effect is used to denote X-rays from electrons scattering off a photon. The photon gains energy.
So, I was wrong in my terminology.
I apologise. In my (weak) defense, they are basically similar and are just terms in the feynman diagram expansion for simple scattering.
Penny
In fact, I was ok. The effect is called
NUCLEAR Inverse Compton Scattering, and Bremstralung is an example of it.
Terminology-yechh!
Formulas, math, principles!
Penny
I’m curious about one thing concerning the Explorer I launch. If the discovery of the Van Allan radiation belts came as a big surprise then how did physicists explain the aurora borealis prior to 1958? Did they think it was a purely high altitude meteorological phenomenon and not related to anything happening in outer space?
“Gagarin - first man in orbit??? Hmmm read those….”
Interesting article. It does verify something I had read a long time ago, which was that Gagarin was trained as a parachutist. During re-entry at some point he popped open the hatch of his Voshkod capsule and jumped into the wild blue yonder. Not sure at what altitude this took place at or whether he was still wearing his space suit, but it’s definitely a strange re-entry scenario. I don’t know if they were afraid of the final impact speed killing the cosmonaut or what, but this seems to be the re-entry mode for the first few Soviet manned flights. They mentioned this in the article about Ilyushin so it lends credibility to it.