Author Topic: Threats from Space: Efforts to Track and Mitigate Asteroids and Meteors I & II  (Read 16501 times)

Offline JohnFornaro

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Robotic spacecraft will always be better than humans at scientific data gathering, mostly because of the multiplicative effect. If you send a human, only that human gets to gather that information. Whereas with complex imagery and complex sensors you can spread the information over a wealth of scientists.

Well, I've heard of a congress of baboons and a gaggle of geese.  Did not know about the grouping: A wealth of scientists.

You are probably right that a scientist equipped with clay tablets and a cuniform stylus will gather less information than robots with those "complex sensors" you mention.  However, the intent would be to send an scientist operating a swarm of probe sats in near real time, by virtue of proximity to the NEO's.

I don't necessarily agree with the prioritization of a human mission to a NEO, but it is false that robots are "always better than humans" at gathering data.  It is never "either/or" regarding robots and humans.  It is always, "case by case".
Sometimes I just flat out don't get it.

Offline Rocket Science

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If you want to do a NEO as part of a hardware shakedown test for a Mars mission fine. If that is “the mission”, that’s just lame....
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Offline QuantumG

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Asteroid sample return has been demonstrated on a very small scale by Habayusa.  Making that work better and on a larger scale and applying it to many NEAs is certainly going to be much cheaper and faster than than sending humans to a similar number of NEAs.

.. and?

You're making a tradeoff that isn't on the table. I don't know why people insist on having the humans vs robots argument.. there's never going to be a magical feat of logic that causes human spaceflight funding to shift to robotic exploration.


Human spaceflight is basically just LARPing now.

Offline woods170

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I hate to admit it but QuantumG hits the nail smack-center on the head.

Offline Proponent

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Asteroid sample return has been demonstrated on a very small scale by Habayusa.  Making that work better and on a larger scale and applying it to many NEAs is certainly going to be much cheaper and faster than than sending humans to a similar number of NEAs.

.. and?

You're making a tradeoff that isn't on the table. I don't know why people insist on having the humans vs robots argument.. there's never going to be a magical feat of logic that causes human spaceflight funding to shift to robotic exploration.

I expect no such shift.  I'm just pointing out that if learning enough about asteroids to be able to defend against a hazardous one were to become a high priority, then the rational thing to do would be to build many robotic probes.  Build lots of OSIRIS-RExes, because the robotic technology is closer at hand and much cheaper.

If, contrary to my expectations, asteroid defense becomes a high priority, I think a substantial boost in funding of robotic asteroid probes  is much more likely than the enormous boost in funding of human missions that would be required to provide an equivalent level of knowledge about asteroid deflection.

Offline QuantumG

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I expect no such shift.  I'm just pointing out that if learning enough about asteroids to be able to defend against a hazardous one were to become a high priority, then the rational thing to do would be to build many robotic probes.  Build lots of OSIRIS-RExes, because the robotic technology is closer at hand and much cheaper.

If, contrary to my expectations, asteroid defense becomes a high priority, I think a substantial boost in funding of robotic asteroid probes  is much more likely than the enormous boost in funding of human missions that would be required to provide an equivalent level of knowledge about asteroid deflection.

You're still making either-or statements!

The budgets are mostly unrelated.. yes, there's a theory that robotic exploration wouldn't get as much funding if human spaceflight were cut, and there's occasional raiding of budgets, but ultimately robotic exploration is not in competition with human spaceflight.

The only question worth asking is if human spaceflight could deliver any data about asteroid/comet threats that is worth having. The answer is obviously yes, and that focusing human spaceflight on that goal is better than the alternatives. (at least it's obvious to me, as defending the planet is more worthwhile than boring holes into LEO and it gives an intermediate goal before colonization begins, others may disagree).

Don't bring up robotic exploration when someone starts a conversation about the value of sending humans to explore asteroids. The two are completely unrelated.
Human spaceflight is basically just LARPing now.

Offline Proponent

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You're still making either-or statements!

Yeah, and if they happen to be true, I'm not sure I see the problem.

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The budgets are mostly unrelated.. yes, there's a theory that robotic exploration wouldn't get as much funding if human spaceflight were cut, and there's occasional raiding of budgets, but ultimately robotic exploration is not in competition with human spaceflight.

I basically agree.

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The only question worth asking is if human spaceflight could deliver any data about asteroid/comet threats that is worth having. The answer is obviously yes, and that focusing human spaceflight on that goal is better than the alternatives. (at least it's obvious to me, as defending the planet is more worthwhile than boring holes into LEO and it gives an intermediate goal before colonization begins, others may disagree).

Sure, a human NEA mission could deliver useful data.  As Blackstar pointed out several posts up, however, what's really needed are visits to many NEAs, and that's really implausible with human missions.  And it would be massively ironic if the people who decide these things decided that for safety a human mission had to be preceded by a robotic mission, as many have argued in this forum.

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Don't bring up robotic exploration when someone starts a conversation about the value of sending humans to explore asteroids. The two are completely unrelated.

It's funny, but I could have sworn the topic was something like efforts to track and mitigate asteroids and meteors.... :)

Offline QuantumG

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Sure, a human NEA mission could deliver useful data.  As Blackstar pointed out several posts up, however, what's really needed are visits to many NEAs, and that's really implausible with human missions.

I don't disagree with any individual statement here.

I'll ask again: what's one got to do with the other?

The only reason to bring it up is if you think the money that would be spent on a human mission could be shifted to what's "really needed". You just agreed that this isn't historically possible.

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And it would be massively ironic if the people who decide these things decided that for safety a human mission had to be preceded by a robotic mission, as many have argued in this forum.

.. and? Are you trying to say that sending a robotic mission to explore a particular asteroid means that later sending humans to explore the same asteroid would not deliver any more useful data? If not, what are you saying here?

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It's funny, but I could have sworn the topic was something like efforts to track and mitigate asteroids and meteors.... :)

We don't currently know enough about asteroids (or comets) to seriously say we can mitigate them.
Human spaceflight is basically just LARPing now.

Offline Robotbeat

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I hate to admit it but QuantumG hits the nail smack-center on the head.
I agree, but don't encourage him! ;)
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Offline Blackstar

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I hate to admit it but QuantumG hits the nail smack-center on the head.
I agree, but don't encourage him! ;)

No, he's confused the whole issue. We're not talking about "space exploration" in general here, where the humans vs. robots angle is tired and over-simplified. We're talking about searching for, studying, and mitigating the threat of asteroids. And in that case the humans make no sense. What is needed for that is:

-good search data (humans not needed)
-good characteristics/ground truth on a lot of asteroids (humans not needed here either)

Sending a human mission to a single asteroid, or even a couple of them, isn't going to help at all, because the data gathered is not going to be applicable to the much broader sample size. It's not the reason to do it, and it's not a good reason to do it.

Go read the NRC study. They looked at the issue and came down pretty clearly on it.

Offline Lar

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I hate to admit it but QuantumG hits the nail smack-center on the head.
I agree, but don't encourage him! ;)

No, he's confused the whole issue. We're not talking about "space exploration" in general here, where the humans vs. robots angle is tired and over-simplified. We're talking about searching for, studying, and mitigating the threat of asteroids. And in that case the humans make no sense. What is needed for that is:

-good search data (humans not needed)
-good characteristics/ground truth on a lot of asteroids (humans not needed here either)

Sending a human mission to a single asteroid, or even a couple of them, isn't going to help at all, because the data gathered is not going to be applicable to the much broader sample size. It's not the reason to do it, and it's not a good reason to do it.

Go read the NRC study. They looked at the issue and came down pretty clearly on it.

"Fellow Traveler" (by William Barton who posts here from time to time, and his writing partner) is dated but still a good read... supports your conclusion.

I think it's clear we don't need humans for gathering data... lots and lots of relatively cheap robotic missions are needed. Not just one, but tens or dozens.

Where humans might come in handy would be if we are going to capture or divert a NEA, the additional flexibility and dynamic response might help.
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Offline Proponent

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Sure, a human NEA mission could deliver useful data.  As Blackstar pointed out several posts up, however, what's really needed are visits to many NEAs, and that's really implausible with human missions.

I don't disagree with any individual statement here.

I'll ask again: what's one got to do with the other?

The only reason to bring it up is if you think the money that would be spent on a human mission could be shifted to what's "really needed". You just agreed that this isn't historically possible.

What I question is the link between human missions and mitigation of the NEO threat.  I'm saying that in practical terms the two have little to do with each other.  More specifically, I was responding to this statement of yours:

Why does it always have to be an either/or question when it comes to humans vs robotic?

You  get different data from each. I wasn't claiming you could do without  the robotic probes, but mlindner was claiming you could do without  sending humans.

No-one can sensibly claim that any number of today's probes will return the kind of data we'd get from sending humans.

When  discussing Mars, the answer is often given: build better robots, or  wait until AI is available (yeah right). The implication being that there's no rush.  When talking about planetary defense, that logic simply doesn't work.  We need all the available data, and as quickly as practical.

I claim the relevant data can likely be collected faster (your criterion: personally, I'm not sure there's really such a rush) with robotic probes than with humans.  The National Academies seem to agree with me (though, the truth be told, it might be more a matter of me agreeing with the National Academies :)).

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And it would be massively ironic if the people who decide these things decided that for safety a human mission had to be preceded by a robotic mission, as many have argued in this forum.

.. and? Are you trying to say that sending a robotic mission to explore a particular asteroid means that later sending humans to explore the same asteroid would not deliver any more useful data? If not, what are you saying here?

I'm saying that the presence of humans probably won't add much when it comes to examining the very small NEAs we're talking about.  At the same time, the constraints imposed by sending humans will make it more difficult to visit the most interesting objects (to say nothing of the cost).  Human missions can help a little, but without a huge increase in human-spaceflight funding, they're not going to contribute greatly to mitigating the NEO threat.

Offline Proponent

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Where humans might come in handy would be if we are going to capture or divert a NEA, the additional flexibility and dynamic response might help.

I can't completely rule out scenarios in which humans would be helpful in diversion, but let's consider the more plausible techniques.  The first one that comes to mind is B612's gravity tractor.  Since this take years and requires no physical contact with the NEO, humans have no role at all.  Similar comments apply to laser deflection.

If the NEO actually had to be physically grappled and wasn't too dangerous to approach, maybe then I can see how humans would make it easier.

If it comes down to blowing something up (which seemed to be the most popular approach among congressmen at the recent House hearing), I doubt there would be any need to physically implant a bomb on the surface, and you wouldn't want astronauts anywhere near it when it went off.  If there is any scenario in which you want to do this, it's probably a last-minute one, when there's no time for deflection.  In that case, the lesser advance time and greater acceptable risk for a robotic mission would be big advantages.

Offline Blackstar

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1-I think it's clear we don't need humans for gathering data... lots and lots of relatively cheap robotic missions are needed. Not just one, but tens or dozens.

2-Where humans might come in handy would be if we are going to capture or divert a NEA, the additional flexibility and dynamic response might help.

1-I'm not sure of the number. It may not be tens or dozens. One of the problems is that at least so far there's no good way to figure out what an NEO is like just by looking at the spectra, especially from a distance. Is it a rock or a rubble pile? Can you figure that out without, say, actually putting a small craft in orbit around it and figuring out the gravity and if it has any voids? Maybe even dozens of in situ analyses might not answer the question, so that requires that you develop a response that takes into account a wide range of options. Dunno.

2-Probably not. There's a chart that is included in the NRC report that shows a range of options, from the gravity tractor to kinetic impactors to nuking it. My personal view is that the gravity tractor is an unlikely option. Although its advocates like to tout the simplicity of it, the reality is that it has to be highly reliable, because it has to operate near the asteroid for a very long time in order to have an effect. It has to be continually thrusting in close proximity to another body, which is not something that we've done (Dawn and DeepSpace-1 operate entirely differently.) Talking to spacecraft designers, they start to shake their heads nervously when you tell them that it has to work without failing for a long period of time. That means you probably send two, or three as insurance, and the complexity goes up.

I think that the far more likely response would be a politically acceptable kinetic impactor (with lots of backups), and a secret project to develop a nuke just in case the kinetic impactors don't work. But no matter what the response, what you're likely to do is hit the thing, spend awhile seeing what effect you've had, and then hitting it again. Humans just get in the way of such an effort. You want to devote all of your attention to moving the rock, and not to keeping the humans alive. They would be a distraction to the mission, not an asset.

Offline Proponent

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OOPS!  How could I have forgotten kinetic impators....

Offline mlindner

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If it comes down to blowing something up (which seemed to be the most popular approach among congressmen at the recent House hearing), I doubt there would be any need to physically implant a bomb on the surface, and you wouldn't want astronauts anywhere near it when it went off.  If there is any scenario in which you want to do this, it's probably a last-minute one, when there's no time for deflection.  In that case, the lesser advance time and greater acceptable risk for a robotic mission would be big advantages.

I hope if we ever get this last chance scenario that we don't choose to try to vaporize the asteroid (if it was even possible). Instead of one large rock you now have a mass of dust of the same mass. Instead of impacting the planet and blasting a ton of dirt into the atmosphere, you instead superheat the atmosphere and kill every living thing that isn't an extremophile. Let's keep the silly idea of blowing things up away from consideration.
LEO is the ocean, not an island (let alone a continent). We create cruise liners to ride the oceans, not artificial islands in the middle of them. We need a physical place, which has physical resources, to make our future out there.

Offline QuantumG

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I'll take all the data I can get about threats to humanity.. thank you very much.

I agree that many robotic probes is preferable to sending humans.. but it's not an either-or choice. Both should be sent. It's that important.

As for the NRC report, I haven't read it but if they're saying what you say they are saying then I think they're wrong. Is that okay? Can I disagree with a report? Or is it one of the gospels?
Human spaceflight is basically just LARPing now.

Offline Blackstar

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1-I agree that many robotic probes is preferable to sending humans.. but it's not an either-or choice. Both should be sent. It's that important.

2-As for the NRC report, I haven't read it but if they're saying what you say they are saying then I think they're wrong. Is that okay? Can I disagree with a report? Or is it one of the gospels?

1-Cite any relevant data that supports the claim that humans would add anything to that task. For good measure, cite any relevant data that indicates that this is a cost effective use of funds.

2-Feel free to disagree. Also feel free to explain why you are more credible on this subject than a collection of the United States' top asteroid experts.
« Last Edit: 04/01/2013 11:58 pm by Andy USA »

Offline QuantumG

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1-Cite any relevant data that supports the claim that humans would add anything to that task. For good measure, cite any relevant data that indicates that this is a cost effective use of funds.

The limitations of robotic exploration have already been discussed.
« Last Edit: 04/01/2013 11:58 pm by Andy USA »
Human spaceflight is basically just LARPing now.

Offline Robert Thompson

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