Talk:Van Allen radiation belt/Archive 1

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See also: Talk:Van_Allen_radiation_belt/summary

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Not an edit war

Firstly, the term "ring current" isn's specific just to Earth alone; it's a generic term, Jupiter for example also has a ring current. Van Allen belt, on the other hand, is Earth-specific, so when giving the composition of the ions trapped within it it seems more appropriate to me to put that information in the Van Allen article.

Also, you added the line "Electrons constitute the outer belt while protons form the inner belt." This is signficantly different from the previous material, which indicaed that the outer belt was composed of protons, alpha particles, and O+ ions. Where did you get that information? There's a contradiction now. Bryan

The previous material told me that the ring current contains such particles but I don't think it said anything really specific about the outer belt.

Protons are the most important component of the inner zone.

The peak electron fluxes in the outer zone exceed those in the inner zone by around one order of magnitude.

If you know this to be otherwise, feel free to change it. Lir 00:42 Nov 13, 2002 (UTC)

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Lir, you have been making many changes with unsatisfactory research. I don't have time to keep cleaning up after you personally. That's why I'm going to auto-revert changes that contain innacurate information. I suggest you do better prior research before making further changes. Feel free to pre-check proposed changes on Talk pages, which may save future edit wars. -- April 01:02 Nov 13, 2002 (UTC)

April. What is wrong with the article? Lir 01:03 Nov 13, 2002 (UTC)

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Blatant reverting is really dumb. Yes, Im well aware there are some things in that article Im not too sure about. If you know something I don't---then you better write about it or else your article wont be educational or informative--there are also things in the article that I have added and I dont think you disagree with---so reverting is stupid-you need to correct errors instead of avoiding them Lir 01:08 Nov 13, 2002 (UTC)

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Lir and April, both. Unless either of you link to resources about your "knowledge" of the Van Allen Radiation Belt from, NASA, JPL, the European Space Agency, a serous university doing research in the matter, or verifiable published (on paper) material, you are engaging in an edit war of your memoric recollections and this will quickly degenerate. Christopher Mahan

NO CHRIS. We are not engaging in a pointless edit war. We are engaging in a, "WHAT IS WRONG WITH MY ARTICLE SO WE CAN FIX MY ERRORS AND IMPROVE ON IT" rather than just deleting everything and not discussing anything. Lir 01:12 Nov 13, 2002 (UTC)

Lir, I'm inclined to side with April. She is a serious student of science, and you fool around a lot -- even more than zany guys like me :-)

Please cooperate with April. --Ed Poor

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Lir, nothing personal, but please leave comments alone. If you feel offended by something written, then please send a note to the author (it's called email) and ask them kindly to remove their comment or reword it. Christopher Mahan

Huh? Lir 03:37 Nov 13, 2002 (UTC)

moving stuff from Talk:Space elevator

This stuff seemed more relevant at Talk:Van Allen radiation belt than Talk:Space elevator. I hope you can use it on the main Van Allen radiation belt article. -- DavidCary 10:19, 27 May 2004 (UTC)

I hope you cross referced it adequitly as it will be of interest to space elevator fans and perhaps should not have been moved.

The original author of Van Allen radiation belt obviously knows the subject better than I, but he got sloppy in places ie this paste: The electrons here have a high flux and along the outer edge and E > 40 Kev electrons can drop to normal interplanetary levels within about 100km (a decrease by a factor of 1000). This drop-off is a result of the solar wind

I think he is saying that certain allignments of the flux of ions from the Sun and the magntic flux allignment cause the temporary 1000 times drop off, but I don't know how to fix this sentence. Also he says the belt is diffuse, has high flux and high density which seems contradictory. Some approximate electons per cubic meter in each case would solve this problem if someone can estimate.

-- Rncox

Van Allan belt problem

I see that this space has mostly been used to discuss the space elevator issue within the Van Allen Belts, however I was wondering if there could be any further explanation on the statement made in the original article: "Energetic electrons form two distinct radiation belts, while protons form a single belt. Within these belts are particles capable of penetrating about 1 g/cm2 [2] of shielding (e.g., 1 millimetre of lead)." My main question is...what does it take to actually prevent the radiation from entering the spacecraft. Does the actual thickness of the lead need to be greater than 1 mm to prevent it....or? Buckeye61729 (talk) 17:20, 2 June 2008 (UTC)

The Edwards elevator doesn't suffer Van Allen problems that notably because it is quite fast.

The Edwards elevator tether and climber may be little affected by Van allen radiation, but both is quite slow compared to the ions and compared to orbiting space craft in the Van Allen belts. The atomic oxygen does errode the CNT = carbon nano tubes, but I think atomic oxygen is mostly a problem at altitudes of less than 100 kilometers.

-- Rncox

200km/h is slow. 3km/s is fast- but that's a rocket, not an elevator Wolfkeeper

200km/h is fast for a space elevator design.

Yes...

At worst, it'll be in the inner belt for about a day, suffering peak radiation only for a few hours.

That's very, very bad. Radiation sickness, teeth falling out, head swelling up, all kinds of bad. I mentioned somewhere- Apollo had about 1% of a dangerous dose; the space elevator goes 200x more slowly. Of course even partial shielding would help a lot; you might merely have a vaguely worrying dose.

Actually, according to the 25 Sv/year number listed in Van Allen radiation belt and the dose effects listed under radiation poisoning, you'd only run into serious problems (risk of death) if you stayed in the belt for a couple of weeks or more. A few days would give you an increased risk of cancer and hard-to-notice symptoms. This assumes 3 mm of aluminum as shielding, according to the article. --Christopher Thomas 23:45, 25 May 2005 (UTC)

Sounds wrong. The 2004 conference had a talk by Jorgensen. His conclusions are:

● Radiation field is severe.

● Shielding with Aluminum is not economical.

● Shielding with a magnetic field may be feasible

● Reducing dose by going faster is not very effective.

● Larger/Heavier climbers are more efficient when

shielding with a heavy material (contrary requirement

to talk by Ben Shelef).

● Climber mass and cost to orbit are impacted.

● Power requirement could be impacted.

As far as I know, he didn't look at the magnetic shielding in any massive detail; by all means check out the paper at: http://www.isr.us/spaceelevatorconference/FINAL_Conference_Presentations/Radiation/Jorgensen_Radiation.pdf

WolfKeeper

I've read the presentation slides, and I find the conclusions you drew from them rather odd. Specifically:

• The dose effects reported are consistent with the ones under radiation poisoning. The only difference is the exposure assumed.
• Aluminum looks quite effective at shielding. 3mm corresponds to the 10⁰ density region, which reduces dose to on the order of 100 rad (equivalent to 200 rem for protons), mostly from very-high-energy protons. This goes down roughly in proportion to the thickness of the shielding. Getting 10¹ g/cm² is no problem - this corresponds to walls 3 cm thick. Your cargo will still weigh much more than your capsule.
• The dominant form of radiation causing damage inside an aluminum can is very-high-energy protons. These are exactly the type of particles that magnetic fields are _bad_ at blocking, which is clearly illustrated on slide 16. If anything, their current values are underestimates, based on magnetic mirror and bending magnet calculations I did for other purposes. As a result, I question the presenter's conclusion that a magnetic solution would be feasible even if the mass of the cryostat for the superconducting coils was less than the mass of aluminum plating required for equivalent shielding. Slide 26 expresses reservations about feasibility, which don't seem to have made it to slide 30.
• The conclusions on slide 30 state that going faster doesn't help much, but the plot on slide 27 seems to indicate a linear or superlinear benefit vs. shielding mass for any reasonable elevator speed, making that conclusion questionable. Absolute dose to be shielded against is intrinsically linear with respect to travel time, so this conclusion seems puzzling on several levels.

Sure, the radiation dose is inversely proportional to speed, but you'd have to go awfully fast to make a really big difference. WolfKeeper

In order to make a space elevator cost less than conventional launch, you already have to go awfully fast. The total cargo in transit at a given time is at most comparable to the weight of the elevator, and possibly much less (depends on how much of a safety factor you can afford to build into the elevator; if it's near materials limits, the answer is "not much"). --Christopher Thomas 08:11, 28 May 2005 (UTC)

In summary, while it doesn't look healthy to ride a lightly-shielded elevator _regularly_, a single trip doesn't look particularly lethal, and conventional shielding seems to be the best approach to reducing exposure for a given elevator geometry.

I really don't think you can give passengers radiation sickness.WolfKeeper

That depends on how badly the passengers want to go into space. If they plan to make a single trip, it'll give them an increased risk of cancer down the road, and not much else. I'm sure you can name people who'd buy a ticket. I can. --Christopher Thomas 08:11, 28 May 2005 (UTC)

The _most_ effective approach seems from the slides to be to construct the elevator off-equator, so as to not intersect much of the lower belt. --Christopher Thomas 19:51, 26 May 2005 (UTC)

Only maybe. I haven't seen how much extra cable mass building a 47 degree offset cable needs. It seems substantial, but I don't know how substantial.WolfKeeper

You can actually calculate this pretty easily. The curved elevator will be shorter than the piecewise-linear shape formed by the tangent from the anchor point, and a line drawn from the earth's centre of mass to the far terminus. The change in distance works out to under 3000km for sane geometries. The pertinent question is how much extra tapering this gives. At 120 GPa/density 3, it's a factor of 2. At 60 GPa, it's 4, and it's 8 at 30 GPa. For a fixed earth-bound terminus size, this is the factor by which the elevator gets heavier, but if you instead assume that your cargo transfer rate is not limited by the terminus size/load capacity (but instead the whole cable's weight), you get almost no weight increase (as the length increase occurs on the most tapered part of the cable). Which scenario is the case depends on the design of the cable and how fast you can make elevators run at various altitudes. --Christopher Thomas 08:11, 28 May 2005 (UTC)

You should probably check out Blaise Gassend's paper on non-equatorial cables. In particular he claims that the length is mostly irrelevant (I'm not 100% convinced by his argument on this), but more importantly he makes the point that off-equatorial cables inevitably have high tension at the attachment point. This aligns more closely with the qualitive analysis I have done too. I'm therefore fairly sure that your calculation is incorrect, since you haven't taken that effect into account. Still, Blaise's calculation is somewhat flawed as well, since he takes a equatorial cable and moves it north, rather than reoptimising it, and he figures on a payload of 0% at 48 degrees which is very pessimistic. Even so, the hit is clearly substantial; so I'm left wondering whether off-equatorials are worth it in fact, it may be better to just double a equatorial cable up and use the extra 100% payload for more shielding, although that too can have negative implications on power beaming.WolfKeeper

My calculations are an approximation, but a reasonably good approximation. To get the correct values, you'd have to numerically integrate a fairly nasty set of equations, but the upshot is that because only a very small fraction of the cable's mass is under additional tension, I wouldn't expect it to have a large impact on the cable's size. If anything, my values should be overestimates, as I took an upper bound on the cable length (the curve will be shorter than the piecewise-linear version), and assumed that all of the added length was being pulled down at 1g (in practice it's high enough up for forces to be lower). In the worst case, though, tension in the non-equatorial segment would average about 1.5 times what you'd expect from a vertical cable, making the characteristic length 1.5x shorter, giving you about a factor of 3, 8, and 64 for 120, 60, and 30 GPa if terminus-limited, using pessimistic overestimates for safety. If you aren't terminus-limited, then it's again a non-issue, for reasons mentioned previously (cargo on the elevator at any one time is proportional to the mass of the elevator, meaning a thinner terminus doesn't hurt you). --Christopher Thomas 03:41, 29 May 2005 (UTC)

But there seems to be a serious error in the paper. He says on one page that the amount of equipment needed to do lifesupport for humans may be about 20 tonnes. However, he fails to take account of the potential shielding effects of this equipment; by carefully arraying it around the passenger areas you may be able to get *great* shielding. That's a big screw-up IMHO. Of course the economic argument may very well be true, but it looks to me that his conclusions on the effectiveness relate to the economics, rather than the radiation. And the economics may be self-reinforcing here- if humans can safely go up it they may do it a lot, and then the economics of elevators tend to improve. I'm actually slightly more optimistic.WolfKeeper

It sounds like he's assuming a very large number of passengers. Food and water for a week for one person weighs about 20 kg, tops. Oxygen for that time weighs at most about triple the weight of the dry component of the food (say 20 kg oxygen, tops). That gives you 40 kg of supplies per week per 100 kg of passenger-plus-carry-on-baggage. For trips lasting a week or less, the vast majority of the mass is the passengers (not counting shielding). If you're using consumables as shielding, you'd probably just use a double hull and fill it with water (sewage basin somewhere in there too; it can be recycled topside, or dumped downside). You'll need a lot more mass than this for shielding for practical car sizes, though (assuming 10¹ g/cm²). You'll want aluminum and kevlar for micrometeorite shielding, anyways. --Christopher Thomas 08:11, 28 May 2005 (UTC)

Apollo astronauts received most of their dose from GCR (Galactic Cosmic Radiation) and solar particles unrelated to the Van Allen belts. Apollo also had nothing that was specificly "shielding"; they had the aluminum skin (being a metal, it has problems with Bremsstrahlung radiation, but with a low atomic number, it's not *too* bad as insulation), and probably the biggest amount of absorption from the fibrous insulation. Any system where there was serious worry about radiation, however (for example, a mars mission) proposes using plastics (such as LDPE) or liquid hydrogen as physical shielding. There was no particular reason for serious shielding, if only for the fact that Apollo hardly touched the belts (due to that whole "earths rotation not matching up with the shape of the radiation belts" thing that you keep forgetting about) Rei 21:11, 26 May 2004 (UTC)

Kinda, Apollo chose the trajectory to deliberatly miss the worst of them. Spacecraft have infinitely more choices; elevator cars have very few.--Wolfkeeper 00:03, 27 May 2004 (UTC)

At best launching times, it will bypass the vast majority of the belt alltogether. Rei 21:07, 25 May 2004 (UTC)

Doubtful; the earth spins taking the cable and car with it back into danger. The magnetosphere is lopsided due to the solar wind. Apollo was able to do it fast, and could in a very real sense 'step off' the earth and get lobbed through only the very edge of the belt. Apollo had *much* more latitude.

It is in the inner (high intensity) belt for hours, and in the outer belt (low intensity) for (~2 days?). Some other designs for elevators are slow, however, and take as much as weeks, so this section needs to be included.

Also, I think you have some misconceptions about Edwards' design. He placed a much higher priority on getting payload up than down, assuming that is what most business would want. While I'm not sure I agree with that assumption, it is an elevator optimized for that particular task. Any payload going down is payload not going up (well, actually, it's not that simple - timing comes into play, because different parts of the cable have different amounts they can hold, but you get the picture). Rei 15:46, 25 May 2004 (UTC)

AFAIK, the only guaranteed solution is make the cable a lot thicker and just live with the extra shielding.

Active shielding? I asked this question at the last but one Space Access conference to Henry Spencer; who is an expert on space (he was lecturing on the physics of the Van Allen belts at the time). His response was 'it has been looked into, but does not work'. The nearest thing to that is the HiVolt proposal; that's sort of what that is. Unless Rei or anyone else can come up with a reference of how that would work for Elevator cars, I will remove this; as it is extremely speculative at best (this is an encyclopedia dammit!)

Wolfkeeper

How would active shielding "not work"? You're the one who's insistant on references: provide a reference, please - preferably one that explains why it doesn't work. Rei 23:47, 25 May 2004 (UTC)

Not until you provide a reference that shows it *does* work. There's a world of difference between Solar Wind/Flares and the Van Allen belt. One consists of supersonic gas and plasma, the other is charged particles trapped in a magnetic field.

Exactly how do you know that superimposing another magnetic field on top of the Earth's magnetic field doesn't make the radiation worse? (I actually think it would- think about how the Earths poles are regions of much higher radiation, the charged particles actually follow lines of magnetic flux. Here's a hint: you don't.

This is done routinely. It's called a magnetic mirror, and is part of many plasma confinement geometries, among other things. I doubt it'd work for a practical elevator car, but that's not because the principle is unsound - it's because you'd need either an extremely strong field or a very large weaker field to adequately deflect ions with energies of tens of MeV. A variant of this idea was proposed for shielding Stanford torus style space habitats. --Christopher Thomas 23:45, 25 May 2005 (UTC)

Until you can come up with a sensible reference to this being applied in LEO as a defense to the Van Allen belt in general, or even better used on the Space Elevator in particular, this piece is going in 3 days time. You are not a designer of Space Elevators, you are at best an author working on an article writing about it. [[User::Wolfkeeper|Wolfkeeper]]

And you are a user relying on threats to push information through. I just added two *MORE* references to it, to prove that it is effective against the Van Allen belts. The reference count is now three ZERO. You don't remove referenced material with ZERO references, Wolfkeeper.

You have zero references relating it to the subject of Space Elevators. This is not a page where Rei designs the best elevator or active radiation shielding; this is where you cover the existing knowledge on Space Elevators. You are not a worker in this field. If you can't get this simple fact, then I fail to see why you are even here.

You clearly know absolutely nothing about the topic,

Wrong! :-)

so let me enlighten you. First off, read the wikipedia article on the Van Allen belts. The particles are trapped in a so-called "magnetic mirror". This is due to Lorentz forces. When a charged particle moves through a magnetic field, it experiences a force tangential to both the magnetic field and the direction of motion (this is used to good advantage in Penning traps). Consequently, if you create a magnetic field around a spacecraft in the Van Allen belt, any particles moving through the field will be deflected tangential to the field and the particle's direction of motion.

For it to be *effective* shielding the shielding has to actually work on an elevator car. For that the mass must be right, the power supplies must not be too arduous, it must not interact in bad ways with the (conductive?) cable itself (hint: eddy forces), the R&D to produce a working system must not be too high; and it should have a predictable development time, not be too expensive or unreliable etc. etc. etc. It seems to me you've come up with a strawman proposal that active shielding be used; it may very well work, but it does not seem to have gone through any review whatsoever- and you- who just pulled it out of thin air- are proposing that it be placed straight in an encyclopedia! No, that's not right; that's not the way it works.--Wolfkeeper 00:03, 27 May 2004 (UTC)

According to studies, active shielding methods proposed thusfar are effective for protons of energies up to 200 MeV; the high energy inner belt has protons of energies 10-100MeV.

I see absolutely no evidence that Brad Edwards is proposing to use active shielding for the Space Elevator.--Wolfkeeper 00:03, 27 May 2004 (UTC)

Upon reflection, and having read the references, I have left the clock running; I'm not opposed to it staying here *if* you can link it back to the Space Elevator in some way.--Wolfkeeper 00:03, 27 May 2004 (UTC)

Consequently, active shielding is a very realistic option for the inner belt.

And Rei is unanimous in this :-)

The outer belt is weaker.

Magnetic field making the radiation worse?

Rei 16:47, 26 May 2004 (UTC)

Actually that can happen. On the Earth close to electricity pylons you find that the cosmic radiation has scattered off the E-M field and increased the radiation around it. It's measurable.

--Wolfkeeper 00:03, 27 May 2004 (UTC)

Citations? The magnetic fields produced by high-tension power lines are quite weak any significant distance away from them. You'd need a multi-Tesla field to substantially deflect cosmic rays energetic enough to penetrate the atmosphere over that short a distance. --Christopher Thomas 23:45, 25 May 2005 (UTC)

• I'm moving the space elevator stuff back to space elevator (even though that is a bit long too). I left the part on HiVOLT here, although it's a little out of context where I left it.

contradiction

it says: The belts are a hazard for artificial satellites and highly dangerous for human beings and difficult and expensive to shield against.

Yet is also says: Conspiracy theorists have argued that space travel to the moon is impossible because the Van Allen radiation would kill or incapacitate an astronaut who made the trip. In practice, even at the peak of the belts, one could live for several months without receiving a lethal dose.

Project Apollo nevertheless deliberately timed their launches, and used lunar transfer orbits that only skirted the edge of the belt over the equator to minimise the radiation. Astronauts who visited the moon probably have a slightly higher risk of cancer during their lifetimes, but still remain unlikely to become ill because of

I have edited this portion of the article because it makes unsupported claims. This is an encyclopedia and if someone is going to claimt that a person could live within the Van Allen Belts (for months!) then it should be supported. Thus, the article was changed to the current one. Also, I removed the "conspiracy theorists" vocabulary because it automatically has negative connotations that do not comport with Wikipedia's neutrality edict. karelroc123 Oct. 6, 2005

The "months" claim has been removed. If you are going to change the wording to "some people", please show me a reference to someone claiming this who also accepts that Apollo astronauts walked on the moon.

I have also included a detailed reference regarding the statement that astronauts can pass through the Van Allen radiation belt. --PhilipO 00:15, 8 October 2005 (UTC)

I haven't reverted this time, but rephrased to a factually correct statement. Secondly, the wording "it is believed" is not correct here. It is a fact - that is why I have included the reference at the end of the paragraph. Why should this be changed from its current form? --PhilipO 00:27, 8 October 2005 (UTC)

• there should be at least a mention of the conspiracy theorys. maybe a link to how and why the levels of radiation are called what they are?

Nuclear weapons

It would be nice if someone "in the know" could write up a little summary on how nuclear weapons can create artifical Van Allen belts. See Operation Argus. --Fastfission 14:53, 9 September 2005 (UTC)

That would be a good thing to add. The Starfish tests caused a temporary increase in radiation that destroyed Telstar and a number of other US and Soviet satellites. It was quite an embarassment. DonPMitchell (talk) 19:23, 16 August 2008 (UTC)

Protection Requested

This article should be protected as there is a dispute over neutrality.

¿Where is the inner belt?

I need information about the inner belt (composition and localization). ¿Why is it ignored in the article?

More contradictions

The article as it stands today seems to be contradicting a NASA article on Van Allen belts in that it also lists a third belt:

The low-energy electron belt actually overlaps the volums of space occupied by the proton belt. The electrons carry between 1 - 5 million volts of energy, on average.

In the same NASA article the inner belt is described thusly:

The proton belt is located from about 500 kilometers above Earth's surface and extends to 13,000 km. This Inner Belt contains protons with energies greater then 10 million volts. Scientists currently think that these protons are trapped cosmic ray particles from outside the solar system, or from the Sun itself possibly during severe solar flares.

This contradicts the wikipedia article stating:

The big outer radiation belt extends from an altitude of about 10,000–65,000 km and has its greatest intensity between 14,500–19,000 km.

thus implying an overlap of 3000 km, something that is not indicated on diagrams and would imply there being just one belt.

At present, the Wikipedia article states the following : «The large outer radiation belt extends from an altitude of about three to ten Earth radii (RE) or 13,000 to 19,000 kilometres above the Earth's surface. Its greatest intensity is usually around 4–5 RE.» Given that, according to that impeccable source, Wikipedia, the mean radius of the Earth is some 6371 km, the statement about the extent of the outer radiation belt measured in Earth radii is not compatible with that concerning the extent measured in kilometres. One or both must be adjusted.... Mhenriday (talk) 20:44, 4 February 2011 (UTC)

Also

The inner Van Allen Belt extends from roughly 1.1 to 3.3 Earth radii

is unhelpful in switching units of measurements. If we restate as 7000 km - 20000 km it becomes quite confusing by way of even more overlaps of belts.

I propose those two sections are in a dire need of rewriting and consolidation and that a diagram would help in keeping it clear, not the least in the minds of the editors.

Considering the past editing wars in this article I am not going to do it, no matter the be bold stance. I have seen too many reverts to even consider that. Experience states agreement is needed first.

--12:54, 18 May 2006 (UTC)

Glaring error, one month and counting. There goes the claim that Wikipedians fix errors quickly. --13:39, 17 June 2006 (UTC)

And bam! someone strikes removing this by revertion. I thought deletions in the talk section was considered bad form. This is why I no longer write articles here myself, far too much has been adjusted by editors not bothering to look up the background information. Instead I have limited myself to pointing out errors, that saves me a lot of wasted effort. Now I will reconsider if it is worth bothering with even that. --18:12, 20 June 2006 (UTC)

Just to note that more than a year has now passed and the contradictions remain and the correct description with 3 components is still missing. --85.164.180.77 23:58, 23 June 2007 (UTC)

Good to see you're working hard to fix it. siafu 01:31, 24 June 2007 (UTC)

I would have fixed it had there been any point to it. Look through the history of this talk page as well as the article itself and you will find that fixes are frowned upon. Certain people here are so agressively protective about their views on what the radiation belts should be (never mind what NASA states) that they even delete comments on this page. Slogans like be bold has no meaning when Soviet style redacting is the norm. For that reason I have stopped editing and limit myself to warning the unwary on talk pages just how bad certain articles are. --16:33, 27 June 2007 (UTC)

Proposed Removal of uncited Claim

I would like to propose that this claim in the text be removed. It is uncited and factually incorrect: "Nevertheless NASA deliberately timed Apollo launches, and used lunar transfer orbits that only skirted the edge of the belt over the equator to minimise the radiation."

 Here is a source from Nasa that contradicts the claim of skirting the edges of the belt: [[1]] 

"Apollo astronauts, however, were forced to traverse the most intense regions of the Belts in their journey to the Moon." (Don't worry, they go on to explain-away the hoax theorists. See the link.} Also, there is no evidence that they timed the launches to minimize radiation. That would be impossible as we still to this day cannot predict fluctuations in Van Allen Radiation or solar flares accurately; again see link. If anyone can provide a credible citation for the quoted text above, please provide. Otherwise I'm removing it

I can't give you a citation, but I know it to be true; I've seen a diagram with Apollo trajectories plotted on it. The reason is that if you look at the link you gave, the belt has a particular shape- it's mostly over the equator at the strongest parts. Now the moon's orbit isn't in the plane of the equator, it's far closer to being in the plane of the solar system which is significantly tilted relative to the Earths axis (see Moon- inclination "varies between 28.60° and 18.30° (5.145 396° to ecliptic)"). So as the Earth moves in its orbit and the moon moves the trajectory between LEO and lunar insertion changes. If you launch at certain times of the month/year you would go right through the thickest part of the belt, at other times when the belt is maximally tilted-facing the moon-you can avoid most of it by going *above* the belts. They couldn't completely avoid the belts because they're too thick in the north-south direction, but Apollo deliberately chose time windows to reduce the irradiation by avoiding the strongest part of the belts as far as possible. IRC they still spent a small time in almost the worst regions, but they were able to far reduce this time.WolfKeeper 18:05, 18 May 2006 (UTC)

I won't change the reference as I can't disprove your claim re: Apollo trajectories. However, my understanding is that the belts are toriodal (donut-shaped) along the earth's equatorial axis. As such they would be symmetrical and it wouldn't make any difference what trajectory was chosen so long as it stayed within 65 degrees of the equator. The only way to effectively minimize exposure would be to move from LEO into a lunar trajectory via the North/South pole. Would it be possible for you to link/post the diagram you describe re: Apollo Trajectories? Thanks 86.49.76.137 19:22, 18 May 2006 (UTC)

Sorry IRC it came from a book I was reading in a university library, it's not online, and I don't know if I can find it even if I go back to the library. It didn't stop them being irradiated, it just reduced it by enough that it was worth doing it. They just cut the donut at a higher angle; maybe 30%-50% less irradiance. There's lots of wacky stuff they found out back then; e.g. if you fly the Saturn stack at an angle within the atmosphere you can get 1% extra payload (a tonne!). Much of it isn't online. There's similar stuff being worked out for the Space Elevator- moving the attachment point northwards tens degrees or so reduces the radiation significantly (the reference design for a Space Elevator climber spend about a *week* in the belts... :-( )WolfKeeper 21:50, 18 May 2006 (UTC)

Rotation and magnetic axis the other way round: Corrected picture

The picture of the Earth with the Van Allen Belts: Here is the right diagram with an oblique rotation axis and the vertical magnetic axis: Van Allen Belts schema.

Take it if you want. Michael Palomino 12th October 2006

Your diagram looks wrong to me. The lines of longitude/latitude don't align with the rotation axis. Also the magnetic axis doesn't seem to be offset from bisecting the earth in the way that it needs to to give a South Atlantic anomaly.WolfKeeper 01:00, 12 October 2006 (UTC)

What are the units here?

From the article introduction, "The release of fluorohydrocarbons in the upper atmosphere causes a selective absorption of alpha particles in that space. A conglomeration of such (invisible) clouds are called pseudo–Van Allen belts and are 1x10-9 lower than the real Van Allen belts."

Are they lower in altitude or activity? Is this a percentage difference? If not, then what are the units? anonymous 00:53, 14 November 2006 (UTC)

This statement is grammatically garbled, unclear, and unreferenced. An attempt to Google additional information about "pseudo-Van Allen belts" turns up only two hits, one of which is an apparent quote of the Wikipedia article and the other a passing mention in a forum discussion of global warming. My inclination would be to remove the sentence in question unless/until the original writer can come up with a less confusing formulation that is supported by a reference. Piperh 11:18, 11 March 2007 (UTC)

Universal pictures

I highly doubt the veracity of the claim that the Universal Pictures logo has anything at all to do with the van allen belts. It could easily just be a stylized globe. Provide source for claim other than "it looks like it could be so it probably is" to keep in article.--Deglr6328 05:16, 2 January 2007 (UTC)

You have too much time on your hands, don't you? —Preceding unsigned comment added by 76.177.18.83 (talk)

Well this hasn't been discussed since January and no one was against it - so I'm going to remove it -- trolleymusic 02:55, 5 July 2007 (UTC)

Someone that helped Van Allen

William (Bill) Lawrence was a student at Iowa, and helped build the devices that Van Allen sent up to discover the belt. Wish I knew more about what he actually did, but Bill is now suffering from Alzheimer’s and lives near Temecula California - so I can't get any more information. Before he retired, he worked at KMS Fusion (in Ann Arbor MI) as a nuclear physicist - trying to produce more energy than expended in using lasers to get a fusion reaction. —Preceding unsigned comment added by 198.87.20.200 (talk) 19:10, 18 December 2007 (UTC)

Disbelief regarding apollo

The Encyclopedia Americana Volume 27 p.663 1961 Edition states:...the internal belt (about 10,000 counts per second) is found from 1,400 to 3,400 miles. For this number of counts, the associated radiation would be 10 to 20 roentgens per hour, if the particles were electrons, or 100 to 200 roentgens per hour if they were protons . The outer belt extends from about 8,000 to 30,000 miles and has its maximum intensity near 12,000 miles. The radiation exceeds the maximum permissible human dosage of 0.3 roentgen per hour. Personal comment, as a professional engineer: I may be wrong, but I cannot believe Apollo astronauts traveled through this and were able to survive. Original comment by 70.188.255.197 (talk) moved from article to talk page by Karora 21:30, 1 July 2008 (UTC)

There is quite an good article on Apollo Moon Landing hoax conspiracy theories that debunks this argument. DonPMitchell (talk) 19:31, 16 August 2008 (UTC)

Shielding function against evil

I was shocked when I saw http://www.youtube.com/watch?v=Lt1Yo610lG0 which gives a hint why the belt exists and that the LHC will destroy it. Please integrate this information! —Preceding unsigned comment added by 83.171.185.55 (talk) 19:01, 15 August 2008 (UTC)

Sputniks, Explorers and Propaganda

At some point we should tackle the issue about Soviet discoveries with regard to the radiation belts. There is an excellent article on this in History and Technology 17(2) "Sputniks, Explorers and Propaganda: The Discovery of the Earth's Radiation Belts".

"Abstract: The most important scientific discovery of the early space era - the 1958 discovery of the radiation belts of the Earth - was made in the context of Cold War rivalry between the USSR and the USA. The paper uses previously unavailable archival records to reconstruct the relative contributions of American and Soviet researchers and their interactions during the process of discovery. The former discovered what is now known as the inner radiation belt, while the latter observed the outer radiation belt and gradually came to realize the existence of two distinctively different zones of radiation. The uses of science for the purposes of Cold War political propaganda affected the behavior of scientists and led to the misrepresentation of the events in mass media."

Soviet satellites had highly inclined orbits, so they were the first to detect the band of radiation near the poles, where the outer belt approaches the Earth. Sputnik-2 actually detected this (before Explorer-1 was launched), but Sergey Vernov failed to appreciate the implications.

Sputnik-3 made many important contributions, since it was vastly larger (1.3 tons) and more sophisticated than the early Explorer satellites. It carried Cherenkov detectors, ionization counters, scinitillation counters and fluoroscopes, and proton traps. Explorer-1 just had a simple geiger counter, which could not distinguish anything except a raw count of total radiation. The Sputnik instruments gave the first information about the makeup (photon, electron, protons, heavy nuclei) and energy spectrum of the radiation. It also gave a detailed picture of the "polar belt" of radiation which over time was recognized as part of the outer belt.

The controversy alluded to in the wiki article about Sputnik-3 vs. Explorer-4 is not really valid. The did the same experiment, and Explorer-4 came later and had much more primitive instrumentation. A more compelling argument is Sputnik-3 vs. Pioneer, because the Pioneer (and Luna-1) flew through the outer belt and really showed its shape and extent. DonPMitchell (talk) 19:44, 16 August 2008 (UTC)

"Impact on space travel" section riddled with weasel words

"Allegedly" and "claim" dot the whole section. For instance, "it is claimed astronauts traveled through the Van Allen belts on both the outbound and return trips to the moon." The passive voice alone sets me on edge, and then all of the language in the section smacks of the Apollo hoax conspiracy theories, yet never once mentions them. I'm not sure how exactly to edit the section up to standard, but it needs to be done soon. Lockesdonkey (talk) 16:14, 15 September 2008 (UTC)

Well, you can begin with undoing the last edits by Sabora9. Then reintroduce what may be valuable in this diff. — Xavier, 23:53, 15 September 2008 (UTC)

I attempted to correct this, but it has been repeatedly reverted by Superflewis (talk). Since he reverts it within 10 seconds of every edit and refuses to give a reason other than calling it vandalism, I cannot open a discussion on the matter with him. -80.42.161.45 (talk) 14:51, 17 September 2008 (UTC)

Please see this and this for a clarification on the above discussion --Superflewis (talk) 15:53, 17 September 2008 (UTC)

I approve of Gnome de Plume's edit as correcting the original inaccuracies. It doesn't discuss the effect on manned space travel (my edit cited pages discussing the severity of the radiation dose received by passengers), which could be considered an omission, but it does resolve the neutrality and weasel issues which is what I was chiefly concerend with. -80.42.161.45 (talk) 16:47, 17 September 2008 (UTC)

By all means, if you can find NASA documents which state that the Apollo missions actually did transit the Van Allen belts, bring it on. Watching toolbois like you go through a process of doublethink is very entertaining. 114.78.171.25 (talk) 08:17, 30 March 2009 (UTC)

I have corrected one sentence I saw that was inaccurate coming out of the great revert war of 17 September, up to that writing.

The worst was that it was necessary to shield against the solar wind. The energy of the solar wind particles is very low, so that they have negligible penetrating power, and even a sheet of paper would be sufficient to shield against them. This they never need to be shielded against, and I dropped them.

But I added solar flares, which can produce a lethal dose, but big ones are rare (and modestly predictable), so Apollo risked it for short flights to the Moon. This is a more serious problem for longer trips, as to Mars.

For both Van Allen radiation and cosmic rays, the duration and detailed orbit/trajectory are critical, so there is no pat answer. Eg, an orbit with an apogee at six earth radii and a perigee at 400 km would be very dangerous or lethal if traversed for a year (which I've never heard of any suggested mission doing), but if the apogee was at 500,000 km the time in the belts would be a negligible fraction of the year. The dose due to cosmic rays is worrisome (though not grave) for long flights above a few earth radii (where the geomagnetic shield is lost), and very difficult to shield against, due to their very high energies.

It seems to me that these issues are complex (each radiation source has its own characteristics and needs separate evaluation) and really beyond the scope of an article on the Van Allen belts, so I would just mention the issue here, for Van Allen radiation only, and leave the larger issues to the Apollo hoax article, and a more general article on the hazards of spaceflight. Wwheaton (talk) 00:09, 18 September 2008 (UTC)

At the end of this section it says "An astronaut(!) shielded by 3 mm of aluminium in an elliptic orbit passing through the radiation belt will receive about 2,500 rem (25 Sv) per year.[6]" Well yes, he would! But that would be very foolish, as death is reckoned to follow after exposure to anything in excess of 6 Sv, and even at only 3 Sv death will occur within 30 days in 50% of cases of such exposure!

The target sentence is a misquote from the reference source. It doesn't help the matter under discussion. Astronauts don't travel round the earth in spacecraft which have orbits within the Van Allen belts for this reason! Correction possibilities: (1) remove the sentence, (2) edit the sentence so that it accurately reflects the source information. (3) add extra material that provides more accurate information that is relevant to space 'travel' i.e. the impact of the Van Allen belts on those travelling in space, especially considering that they invariably have to pass through these radiation belts. --Lepton6 (talk) 14:47, 25 March 2009 (UTC)

NIAC proposal

Do we want to reference the NIAC proposal about extracting antimatter from the Van Allen belts? Even that report claims there is only 10 micrograms of antiproton in the entire belt. DonPMitchell (talk) 16:02, 23 May 2009 (UTC)

I modified the sentence to present more information about the proposal.

Forgive me, my visceral response to this proposal is so strongly negative (I think it borders on the ridiculous...) that I have commented it out of the lead for now. I would prefer leaving it out altogether (I think it has very little relevance to the topic of the article), but maybe it could go someplace near the end if you & other editors really think we need it. Of course the total cosmic-ray power into the Earth's atmosphere at energies high enough to make anti-neutrons (presumably the source), over ~6 GeV, must be considerable, maybe a few GW I guess. Cheers, Wwheaton (talk) 18:23, 31 July 2009 (UTC)

Level of danger posed by the belts

Regarding this edit and this edit, by 206.248.134.13 (talk · contribs · WHOIS) and 206.248.134.61 (talk · contribs · WHOIS), respectively:

The existing phrasing ("The belts are a hazard for artificial satellites and moderately dangerous for human beings") should be left as-is. Per this article, a satellite with an elliptical orbit intersecting the belts would receive a dose of about 2500 rem per year, given plating comparable to what you'd use for micrometeorite shielding on a manned craft. This would be very unhealthy for a human (per the rem article, 100-200 rem "will cause illness but will rarely be fatal"), but would mostly be a problem for missions that involved staying in the belt for an extended period. Passing through it on the way to somewhere else would not be fatal (residence time would be hours, and you'd need to loop through it for weeks to reach 100-200 rem).

Numbers for exposure while literally sitting in the most intense part of the belt, vs. passing through it, are a bit harder to come by, but the orbit assumed by the source referenced for the "2500 rem" number assumes an orbit that stays in the belt system plots used by this article. (Altitude above Earth's surface ranges from 200 to 20000 miles, which corresponds to the "1" through "6" radii marks on the article's plots of belt intensity.) --Christopher Thomas (talk) 05:48, 31 July 2009 (UTC)

"(for comparison, a full-body dose of 50 Sv is deadly)" I was under the impression that 5 Sv dose is fatal. 2001:48F8:29:0:ED90:1CB2:69E:932A (talk)

Solar radiation belts

I've rolled back this good-faith edit. My main concern is the change from "does not have belts" to "might have belts that we haven't observed yet". This is a very big difference, and the work mentioned in the edit summary by the ip editor is very old (1970s or earlier, if I'm googling correctly).

The solar magnetosphere has been well-enough studied that I'm pretty sure the belts have been explicitly ruled out by experiment, but it'd be helpful if someone could dig up citations confirming that this is the case, and add them to the article. That said, mentioning the idea of solar belts for historical reasons might be a good idea, but that too would need referencing. --Christopher Thomas (talk) 20:46, 17 August 2009 (UTC)

Impact on space traveling humans

We have the section Impact on space travel, but it doesn't at all discuss the impact of space radiation on humans and living beings, only on electronics. isn't that an omission? __meco (talk) 13:33, 5 August 2010 (UTC)

In fact it is. I wonder what the reason is. —Preceding unsigned comment added by 217.85.236.83 (talk) 22:37, 18 August 2010 (UTC)

Probably mostly due to lack of interest I think, because nobody has traversed the belts since 1972, whereas the effect on satellites is a multi-billion dollar current matter, now that there have been ~400 comsats launched to GSO. The issue was studied fairly extensively early in the Apollo Program and before, of course. A bit of hand-waving I put together ten years ago in response to a "MAD Scientist" question has been referenced some, notably by Phil Plait's writings on the subject, but is hardly the last word. It does have some references to more reliable sources, some of which may now be more available on-line. More recent references may also be found in our Moon landing conspiracy theories article. Anyway, it should not be hard to bring this article more up to date on the issue, a useful chore. Wwheaton (talk) 03:01, 19 August 2010 (UTC)

The ISS is actually in the bottom edge of the belts, it's just that the radiation at low altitudes is significantly attenuated by what little atmosphere there is, but the astronauts still get an (un)healthy dose.- Wolfkeeper 06:38, 19 August 2010 (UTC)

Volcanic origin?

I just removed an unsourced claim, attributed to Alex Dessler, that the radiation belts may be due to volcanic activity. I think this is physically very unlikely, and not at all main-stream, though I am not an expert on Van Allen radiation. A little Google search finds ~9000 hits on {'Alex Dessler' 'Van Allen'}, but looking at the top few I see only things that seem to quote our previous Wikipedia article verbatim — almost all having the phrase: "while Alex Dessler has argued that the belt is a result of volcanic activity". Most appear to be blogs & other lightweight material, nothing that looks like a reliable source. A full-text search of the Astrophysics Data System for {"ALEX DESSLER" "VAN ALLEN BELT"} finds no hits between 1952 and 2003.

At first glance it appears to me as if there may have been an avalanche or loop of citations stemming from that very early (~2002) Wikipedia mention. The editor who made the claim was blocked indefinitely in 2008 as a troll, for whatever that may mean here. Although "Alex Dessler" is redlinked, I think he is a reputable worker in space science. If there is a peer-reviewed article in a scientific journal that supports the claim, we should probably restore it. But I am a bit worried that this could be a classic Wikipedia horror story. Maybe a more experienced researcher or editor can advise or investigate? Wwheaton (talk) 10:50, 18 February 2011 (UTC)

I have received a quick response from Alex Dessler:

I am (sort of) shocked that this is what is reported. It is true that I once made a verbal joke at a meeting where I was making fun of someone (Tom Gold as I recall) to make the point that correlations were not proof of physical causality. You need a viable theory to make the connection. For example, I like this quote, "It has been proven by thousands of experiments that the beating of tom-toms during an eclipse will restore the Sun." This is from E. Bright Wilsons's book (which I read as a graduate student in the early 1950s) Introduction to Research. Wilson did not believe this correlation was true, as I did not believe volcanoes could cause or have any effect on the Van Allen Belt. My point was regarded as funny enough that I believe Wilmot Hess, in one of his books, quoted me in the spirit of a physicist having fun. If he did, the book would have been published in the 1960s. I never put such nonsense in print -- OMG!

This suggests that the Thomas Gold proposal may also need to go, though auroras are definitely related to the inner (electron) belt. I am thinking this case history needs to be reported on some of the project pages — physics, astronomy, space science,... as many as are relevant. It is the first clear instance I have encountered of what appears to be an attempt to undermine the integrity of Wikipedia by covert fallacious editing. It is not trolling, which I think is defined as a deliberate(?) attempt to create destructive commotion via emotion, etc — ie, not covert. The edit that did it was:

07:44, 18 November 2002 Lir (talk | contribs) (7,275 bytes) (undo)

Lir made many many edits, often on other subjects, which probably all need to be reviewed in detail. Aggggh, dreary. Not something I particularly want to get involved in. Wwheaton (talk) 19:22, 18 February 2011 (UTC)

Safe zone

Safe zone should be a disambiguation page; this is a UN term which was of significance in Bosnia Herzegovina for instance.--عبد المؤمن (talk) 13:16, 30 March 2013 (UTC)

New Information 3 Belts

There is a lot of information coming from the new NASA Probes that does not appear to be worded correctly in this article. Several publications have been made and main stream media reports. I will just quote NASA as a source for now but we do not appear to have included this new information yet and images and information are out of date. The images show an inner and an outer belt still but NASA shows 3 belts that appear to be refereed to as sections here. I believe the images of inner and outer belt are now incorrect and should show all 3 belts. The article states the third belt was destroyed but further reading shows it to be cyclic in nature. Article probably needs someone familiar with the subject to review the entire article for a possible rewrite as there are discrepancies throughout based on new information.

http://www.nasa.gov/mission_pages/rbsp/news/third-belt.html --216.58.23.145 (talk) 15:45, 1 May 2013 (UTC)

References

Removal of Van Allen belts

Regarding the proposed removal of the belts: it would be nice to see in the article more information on this. Specifically: what are the implications of this beyond just making space travel safer (e.g. possible damage to the atmosphere or other dangerous effects), and how permanent would this be? Would HiVOLT have to remain permanently to keep the belts drained? — Preceding unsigned comment added by 203.59.161.167 (talk) 10:36, 14 December 2013 (UTC)

Global Warming

Is there any study / experimentation about a possible link between Earth Magnetic field, now decreasing with time in recent years, and Van Allen radiation belt capturing LESS highly energetic particles? Assuming that these particles, now not trapped anymore in the belts, would be effective in transferring their energy as heat, when hitting the dense surface of Earth, what could be their possible CONTRIBUTION to global warming (in which possible percentage) ? — Preceding unsigned comment added by 74.57.114.58 (talk) 13:40, 19 May 2014 (UTC)

Not according to NASA you don't fly through the Van Allen radiation belt...

Not according to NASA you don't fly through the Van Allen radiation belt (http://mars.nasa.gov/participate/send-your-name/orion-first-flight/learn/) you don't.... It's what's stopping humans from landing on Mars and becoming martians :) 134.148.67.15 (talk) 09:22, 17 October 2014 (UTC)

134, the webpage you link to has a bunch of pictures of Orion; I see nothing on there about Van Allen belts.Mcswell (talk) 15:49, 26 June 2016 (UTC)

The citation saying that the Apollo astronauts were not killed by the radiation of the VAB because they only went through a "short time" (hours is not a short time to be exposed) is ridiculously biased - by a guy who works for NASA. Not exactly an independent source! Bailey, J. Vernon. "Radiation Protection and Instrumentation". Biomedical Results of Apollo. Retrieved 2011-06-13. http://history.nasa.gov/SP-368/s2ch3.htm "In fact, the astronauts' overall exposure..." (it is not a fact) should be changed to disclose the source: "According to NASA, the astronaut's overall exposure..." — Preceding unsigned comment added by 67.55.221.6 (talk) 05:49, 8 December 2014 (UTC)

67, what possible bias is there? It's easy enough to calculate how long it would take a spacecraft starting out at about 24,000 mph (and slowing as it climbs out through Earth's gravity well) to travel through the VAB. And a short time it is. As for "hours is not a short time to be exposed", it depends entirely on the amount of radiation per unit time. Saying "hours is not a short time to be exposed" is as senseless as saying "miles is a slow speed." Mcswell (talk) 15:49, 26 June 2016 (UTC)

Cutaway drawing inaccurate?

It seems to me that the NASA cutaway drawing contradicts figures given in the article on the altitudes of limits of Van Allen Belts. I am an educator preparing educational materials and this figure is unhelpful, unless it is the other information that is inaccurate. Should the drawing be removed/replaced? Asgrrr (talk) 16:11, 15 June 2016 (UTC)

phrase unclear: was probe destroyed?

This phrase is worded poorly: "In 2013, NASA reported that the Van Allen Probes had discovered a transient, third radiation belt, which was observed for four weeks until destroyed by a powerful, interplanetary shock wave from the Sun.[2]" - Question arises: Was the probe destroyed, or the entire van Allen belt?? 79.196.235.162 (talk) 05:21, 21 June 2016 (UTC)

The belt was destroyed. The singular/plural agreement and proximity of the antecedent to the pronoun leads me to think that this isn't confusing enough to need rewording, but if you have a proposed revision I would certainly like to hear it. VQuakr (talk) 02:10, 22 June 2016 (UTC)

The number agreement is with "which was observed", and while a participle like "destroyed" would usually be construed to have the same understood subject as "observed", people write with dangling participles often enough for it to be potentially confusing. How about "...until the belt was destroyed..."? Mcswell (talk) 15:54, 26 June 2016 (UTC)

Actually, I figured my suggested edit was small enough, non-controversial enougn, and helpful enough to non-native speakers of English especially, that I went ahead and made it. Mcswell (talk) 15:58, 26 June 2016 (UTC)