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The B612 Foundation is attempting to privately raise about $500 million for its Sentinel mission. Sentinel is a space-based survey to discover and catalog 90 percent of the asteroids larger than 140 meters in Earth’s region of the solar system, as well as vast numbers of smaller asteroids. Sentinel will be launched into a Venus-like orbit around the sun, which significantly improves the efficiency of asteroid discovery.
It is hoped to launch Sentinel on a Falcon 9 in 2016 and complete the survey by 2022, which will enable forecasting the orbits of these objects into the 22nd century. In addition Sentinel should improve on NASA’s identification of potentially hazardous objects greater than one kilometer in diameter, which currently stands at about 93%. There will be benefits besides providing planetary warnings such as:
> demonstrating the feasibility and methods of operation of a privately funded space project
> accurately and completely mapping near Earth objects and partially characterizing these objects as precursors to human exploration and possible exploitation
> identifying other objects of interest such as comets.
Sentinel is clearly a very worthwhile project, which could prevent a huge disaster. It is a project one to three orders of magnitude less challenging than a manned mission to Mars. It will be interesting to see what happens, and what that has to say about a privately funded mission to Mars.
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Nice idea! I am checking out the website. Maybe you could ally with planetary resources to find asteroids...
-Koeng
Lets terraform today!
[url=http://www.terraformingforum.com]www.terraformingforum.com[/url]
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I got to go to the 1st ISAF planetary defense conference in Granada, Spain in 2009. B612 and many other groups were well-represented there. I got to have lunch with Rusty Schweikart at that meeting, and spent a delightful evening chatting with former cosmonaut Dumitru Prunariu, as well.
Didn't get to go to the second one in Budapest in 2011, but I'd bet B612 and the other groups were there, too. The risk is real. I think that asteroid defense is a very viable and compelling reason for a much better spaceflight capability than anybody has right now.
Sending one-way probes just about anywhere in the inner solar system is just about as easy as going to the moon one-way, in terms of delta-vee requirements and launch rockets. The size of your payload sets the launch rocket requirement, and we have some fairly big ones now. Atlas-V looks pretty good in the 20-25 ton size to LEO, significantly smaller for escape. Falcon-9 looks good in the 10-ton range to LEO, and Falcon-Heavy is supposed to fly next year (53 ton LEO).
The reason manned missions are so much harder is both the mass of the return means, and the mass of all the life support. We see the same effect of mass-of-return-means even with unmanned sample-return missions. Because of the logarithmic/exponential nature of the rocket equation, the departure mass compounds very rapidly to very ridiculous figures for the one launch/one mission model.
During Apollo, they ignored assembly and refueling in LEO as immature, but they did do lunar orbit rendezvous (a lander) based on the docking experiences with Gemini, which got them down to one Saturn-V launch per mission. There's even more launcher size-reduction potential with assembly/refueling in LEO, which we used to assemble the ISS.
One thing I have noticed is that commercial-market launchers are cheaper to launch (and cheaper per unit of payload if flown at max load) than anything the US government has ever developed or operated (that's NASA, USAF, and US Army, even USN). This is the commercial competition effects driving the builders toward simpler systems with much smaller logistical tails supporting the rockets. That tells me that you are better off choosing something from the existing stable of commercial launchers, than developing a gigantic rocket for which there is no commercial application. But it also inherently means that you use assembly/refueling in LEO.
Assembly by docking of easily-launchable modules is mature. We built a 450-ton ISS out of things around 15-20 tons max. We're just getting started doing refueling in LEO, transferring storables at ISS. There's a lot more to do before transfers of cryogenics in LEO is a mature technology. Which is a really worthwhile technology development for a government space agency to pursue (though none seem to be doing it).
Given a mature refueling technology in LEO, and a change in mindset away from the "traditional" one launch/one mission model, manned missions anywhere in the solar system become technologically "easy", just a matter of expense proportional to departure mass from LEO. The 1950's idea of the orbit-to-orbit transport, with landers as needed, really is the best way to do the big manned missions. If you recover parts (or all) of the transport in LEO, you get to use it again (refueling), which cuts expense dramatically over the useful lifetime of the vehicle.
But, you don't design it fragile just for light weight on a one-shot trip. You have to design it for long life and robust survivability, to be re-flown dozens, perhaps even hundreds of times. That's the kind of hardware you have to launch and assemble. It's quite a different mindset, and quite a different style of engineering.
Nuclear rockets really help with this sort of thing, too. For the transport and the landers. Too bad we don't have any ready to fly. We once did.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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"Dear B612 Friends,
"When we started B612 Foundation in 2002 our focus was on asteroid deflection research and advocacy. We developed several deflection concepts, which are accepted today as standard techniques to prevent an impact. However the key conditional phrase in preventing an impact is, “with adequate early warning.” Realizing that unless we act ourselves humanity is unlikely to have such adequate warning, B612 has significantly scaled up our operations and initiated the Sentinel Mission.
"Today I am asking many of you to join me in supporting B612’s year-end giving campaign. Since June of this year hundreds of individual donors have joined the B612 Board of Directors and Founding Circle members in support of the Sentinel Mission.
"Our goal before December 31st is to have 100 new individual donors join the B612 crew. Your gift of $1,000, $250, $100, or ANY amount meaningful to you will help make Sentinel’s next milestone...If you have already given THANK YOU and if you would, consider forwarding this to a friend and tell them why you supported B612.
"Remember, when you invest in B612 you’re helping to protect humanity from a devastating asteroid impact. Thank you for your support.
"My best,
"Rusty Schweickart
"B612 Foundation
"Co-founder, Chair Emeritus"
http://b612foundation.org/can-you-help-us-get-to-100/
Last edited by bobunf (2012-12-21 16:59:36)
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Facebook Live Chat January 9, noon to 1 PM Pacific Standard Time
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Rusty Schweikart is not the only astronaut taking up the asteroid defense cause. There are several more. I don't know all the names, but I've seen Tom "Skywalker" Jones in print on this subject, too.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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"Good news, everyone! New observations taken in the past few days have now ruled out an impact by the asteroid Apophis in 2036. Which is good, because it turns out to be even bigger than we thought...
"The B612 Foundation was created by scientists, engineers, and astronauts specifically to locate, identify, and possibly prevent asteroids from hitting the Earth—they have a program to build a space mission called Sentinel to track potentially hazardous asteroids. At JPL, scientists are looking into building a similar mission called NEOCam."
From Slate at http://www.slate.com/blogs/bad_astronom … hreat.html
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I saw the same outcomes reported in a variety of news stories, too. One or two of them also mentioned that the probability of impact in 2068 increased (although it is still low).
The flip side is that the further into the future the prediction is made, the less reliable it is, no matter how precise the current observations are. This is because of a plethora of small but significant effects perturbing the orbits, things not well understood at all. Only one of these is the Yarkovsky Effect.
My best guess is that we will have warning times at most of a few years, at worst a few days, with Earth-crossing asteroids. No one is yet worrying about the highly-elliptical or even hyperbolic comets. Warning times for those will be at most days, at worst an hour or so.
We're going to need far more powerful propulsion than anything contemplated now, in order to reach these things in time to do any significant deflection. That's just going to be a fact of life, though few yet acknowledge this. The new SLS/Orion capsule is nowhere near what we're going to need. Neither would any of the electric schemes, or even NERVA or its variants. The only thing I know of with the power to do even a part of this is the old nuclear pulse propulsion scheme, with all the bad feelings that concept seems to spawn.
The other unpleasant fact of life is that the favorite "last-ditch defense" (a nuke detonated nearby to nudge it by radiation pressure and absorbed-heat thermal spalling) is simply not going to work very well on some of these, perhaps the bulk of them. If it's a gravitationally-bound pile of loose rubble, the nuke only disrupts and scatters the material, even though there's no blast wave in vacuum, because the applied forces exceed the local gravity forces.
You just turned a single bullet strike into a widespread shotgun blast, if you do this days or weeks before impact, maybe even months. One visit by astronauts to an NEO is simply not going to provide the experience we need to properly address this problem.
Asteroid defense is very good rationale for a very ambitious space program. But few understand the magnitude of the effort that is needed to mount an effective defense.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Not sure what prompted me to think of this topic but here is a bit of an update in that the reference link has changed...
It’s our mission to build a spacecraft that will map the frontier of space and track the asteroids that may impact Earth.
The Sentinel Mission is the first privately funded interplanetary mission and a model for future space exploration. The Sentinel Space Telescope will provide a unique opportunity for the public to take ownership in a historic space mission that will protect Earth, while providing the necessary roadmap for future exploration. The mission is led by a world-class team of astrophysicists and aerospace engineers, and will map the trajectories of asteroids that may pose a future danger to humanity—giving us the time we need to deflect them. For the first time in history, we in the private sector have the people, technology, and experience needed to carry out this incredible mission.
Features
– Most capable NEO detection system in operation– 200 deg anti-sun Field of Regard, with a 2×5.5 deg Field of View at any point in time: scans 165 square degrees per hour looking for moving objects
– Precise pointing accuracy to sub-pixel resolution for imaging revisit, using the detector fine steering capability
Now I do realize that space is quite big but I think we can do better.
I was think something like a space sonar which could be designed with optical or other bands of energy or electromagnetic frequencies with in our capability.
First we need to think about how far out we want to detect, is the asteroid belt far enough?
Second would be to decide on the type of sensor that we would make use of?
Third arrange them in fixed degrees of seperation as that to which a sonar system is designed to, this will be partly determined by the sensors used in the previous step. The more sensors the better arranged over the spherical surface the better resolution.
This system could also have an active ping mode to help with dark objects as we would look for the reflection using the varing cycle and time period of the pulse so as to search in increments outward.
The more satelites that have this feature sitting out there in a defensive posture means the better chance to detect any incoming objects..
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Last I heard, Sentinel was an IR detector. It always faces outward from the sun, which makes using IR feasible. More, and smaller, asteroids can be detected with IR, because their surfaces are all warmer than deep space background 4 K. With visible optical, all these bodies are pretty close to black, on a black background.
edit 5-11-15: Sentinel was to be based in a solar orbit at about the distance of Venus from the sun. That way most of the asteroid perihelions for NEO's would be outside Sentinel's orbit. And they wouldn't have to solve the too-much solar glare problem of being closer than Venus. Solar panels overheat quite easily, even in space, from too much incident radiation.
Want more and faster detection coverage? Build more Sentinels. Simple as that.
GW
Last edited by GW Johnson (2015-05-11 13:55:02)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Apophis Image Shows God of Chaos Asteroid Apophis Gearing up to Pass Earth
On March 6, Apophis will pass relatively close to the Earth—about 9.3 million miles— meaning it will be near enough to be seen by small telescopes.
It will pose absolutely no risk to Earth at that distance, though. For comparison, the moon is a mere 238,900 miles away.
Afterwards, attention will turn to April 13, 2029, when Apophis will pass so close to Earth that people should be able to spot it with the naked eye. Sky-watchers will see Apophis as a speck of light moving east to west over Australia.
2068, when another close pass is due
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Apophis passes close (at one level or another) just about every 7 years. At 300+ meter dimension, it is somewhat larger than a "city buster" and smaller than a "regional total destruction" body. It is not an "extinction event" body, but if it were to hit us, you really would not like the consequences! The 2029 pass is predicted to occur inside the Earth's synchronous orbit distance, at 38,000 km, center-to-center.
GW
Last edited by GW Johnson (2021-02-20 18:42:54)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Hi GW -
Which is worst for a body of that size - to score a direct hit intact or to break up in the atmosphere and create an airburst effect?
Apophis passes close (at one level or another) just about every 7 years. At 300+ meter dimension, it is somewhat larger than a "city buster" and smaller than a "regional total destruction" body. It is not an "extinction event" body, but if it were to hit us, you really would not like the consequences! The 2029 pass is predicted to occur inside the Earth's synchronous orbit distance, at 38,000 km, center-to-center.
GW
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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For Louis re #13
Thanks for posing this interesting question!
Not long ago, in another topic, it was reported that the extinction event that took out the dinosaurs 65 million years ago might have been a comet that broke up while traveling too close to the Sun after flying in from the Oort cloud. In ** that ** instance, assuming it is correct, being hit by ** part ** of the comet was quite bad enough! However, if the comet had held together, then it might well have passed by Earth entirely, and the dinosaurs would have continued to evolve in our place.
I'll definitely be interested in GW Johnson's response to your question!
(th)
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Ground impacts put dust and dirt into the air plus can ignite fires which continue the sphere of distruction around the site.
Air burst has a more localized area of distruction from blast forces with a much lower chance to cause a flash fire the higher above the ground it is. Look to the Russian example of air explosion.
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