"Gravity Tractor" Could Deflect Earth-Threatening Asteroids

A "gravity tractor" could deflect an Earth-threatening asteroid if it was deployed when the asteroid was more than one orbit away from the potential impact, according to a new study. If the space rock was found heading straight for Earth, a combination of techniques - including a gravity tractor - might save the day.

The study, carried out by NASA's Jet Propulsion Laboratory in Pasadena, California, shows that the weak gravitational pull of a nearby spacecraft could deflect a hypothetical asteroid 140 metres across, big enough to cause regional devastation if it hit Earth.

"Prior to this study, the gravity tractor deflection technique had been proven in only a conceptual way," says Clark Chapman of the Southwest Research Institute in Boulder, Colorado, who was not involved in the study.

Keep reading here.

Related: Large Hadron Collider On A Cosmic Quest In Geneva

Comments

[revko]

Gravity Tractor?

Or Gravy Boat?

You decide!

[Doofus]

C'est toujours quelque chose!

Nobody ever didn't get rich protecting the planet from cosmic catastrophe!

Much more info at... http://www.aero.org/conferences/planetarydefense/2007papers.html

[70sFez]

Hey, could this be used to keep Planet X from entering our solar system?

;-)

Seriously though, NASA kicks butt. I have even been to JPL. In the late 80's I went there to become a NASA certified solder inspector because the company I worked at was designing and building some of the Microwave Sounding Units for one of its satellites.

Summary:
The Advanced Microwave Sounding Unit-A (AMSU-A) is a multi-channel microwave temperature/humidity sounder that measures global atmospheric temperature profiles and provides information on atmospheric water in all of it's forms (with the exception of small ice particles, which are transparent at microwave frequencies). Information from AMSU-A in the presence of clouds is used to correct the infrared measurements for the effects of clouds.

[TMAN]

Any civilization that has successfully traversed it's dangerous, suicidal adolescence and begun the exciting journey to the next incremental step into the Cosmos will have come upon the information, devoloped the technology and finally, the guts and belief in our collective selves to act. It would appear that we are there. If so thats a remarkably good benchmark for us as a species.

All things being equal, the next four years are going to be very intense, indeed as our entire little ss crosses through the galactic plane of the ecliptic (once every 26,000 yrs). We will need to have absorbed this point of view, (derived from C Sagan's philosophical musings) understand the challenge and have the guts to act.

"Yes we can" to borrow a term, not seen lately, (heh).

[GrayGaffer]

HumeSkeptic has the math right, And yes, this is the basis for orbital mechanics. And to those of you who think this a boondoggle/insane/waste of money, you obviously fail to grasp the scale of our solar system vs the scale of the asteroid size for which this is effective. 140 m size asteroid, at least 1 orbit before projected impact, need to shift the endpoint of that orbit by around 10,000 miles? at 2pir the baseline is around 630 million miles, so we are only looking for a .002% effect. Without seeing their detailed math, I would say, yes, certainly within reason.

westcoastsc: 'that large'. no. not 'that large', and don't forget the inverse square law. It will have to be brought into very close range (asteroidal diameters scale) for there to be any discernible effect.

negatives: I am guessing we would need to launch somewhat earlier to get a large craft in the right place at the right time to get into a stable gravitational coupling with an asteroid passing through our orbit, although if it is only one orbit away from impact then it is probably fairly close to us the penultimate time. But the orbital velocity difference is a key factor. How much and what kind of fuel for a large enough craft is our limiting factor. But we probably only need one mothballed in orbit waiting until needed. Now we have the math worked out we should fund it.

[westcoastsc]

Isn't it possible that putting something that large in space could actually draw something to earth?

[Doofus]

No & yes, maybe? Go read 'Footfall' by Niven & Pournelle, about evil space-alien
elephants who do just that. If the space-elephants can do it, then why not OBL?

[Steverino]

Can't they just get Ben Affleck and Bruce Willis to blow the asteroids up?

[spinmas]

Is that related to the "tractor beam"????

[FrankenPC]

I don't get it. Just plant a mass accelerator on the asteroid and use it's own mass to propel it any direction you want. Mass is the problem with propulsion. With an entire asteroid, you would have unlimited mass.

[KenGirard]

I am not sure what you mean by a mass accelerator... To me it is a device that uses magnetics to pull a mass down a section of track/barrel.
If this is the device you are thinking of then consider the following:
1) Non-magnetic asteroids (ice, rock) Who do the magnetics work on these materials?
2) Time. First the space craft has to get to the asteroid, and then it has to land a robotic mass driver on the surface, get that all set up and working (power... where to get power) before it makes any effect.
3) Complexity and moving parts.

Using nothing but the gravity a mass in space naturally produces will start effecting the astoriod as soon as it gets near. All you need to do is get the mass near the asteroid. No complex parts, no set up time, nothing to do but let it sit there.

[Doofus]

The GT has to get there, get in position, and hold that position for years,
firing thrusters (ion beams, presumably) continuously *for years*.
Holding position means keeping a proper constant thrust vector while moving
'up' or 'down' relative to the object's surface as it rotates. FOR YEARS.

More feasible than robot mass chuckers? Maybe, but not so much.

[Doofus]

The only problem with that approach is that such objects are always rotating,
which prevents a 'mass accelerator' ('mass chucker', below) from working
effectively. Not so easy to stop the rotation, apparently. Got to focus the
mass-ejection in one direction, not spray it all around. The 'gravity
tractor' gets around that by not being attached to the object.
Instead, it rides some distance away.

But, mass chuckers could still be used, probably, if you were to
place a few (a lot probably) in appropriate locations on the
object in question, so that at least one was always in
the right position to chuck some mass, as the
object rotated around.

[Doofus]

As long as we're spitballing, use ion thrusters & mass chuckers to
stop the object's rotation, then use high-impulse rocket motors,
preferably nukes, to steer the object out of harm's way,
or even to some useful spot, like lunar orbit,
just to show it can be done!

[muffler]

Sounds like an episode of Futurama. "Now where we gonna find a big ass gravity pump?"

[Big0725]

Maybe we can get a big ass particle acclerator to create a singularity and suck it in, with the rest of humanity.

[muffler]

It's fine because using our warp drive capabilities we could take a 5 minute warp 9 flight out to the asteroid and beam down to collect some samples. Then we could use the gravity tractor to pull it into orbit around Jupiter and proceed to mine the ore and other resources for our antimatter reactors. I am a bit concerned since our food replicators have been on the fritz recently.

[ruddie]

This is what the smart men in our country are thinking about ?
Boy are we in trouble.

[Lupin77]

This doesn't matter. When Cern in Switzerland turns on their machine this month - we'll all be toast.

[Americano]

Gravity tractor? Wow! If you believe that, I have over here behind curtain number one, "We are selling the Brooklyn Bridge for One devalued US Dollar!!!

[KenGirard]

Did you read the article? A gravity tractor is a system that uses the normally occuring gravity of any mass to pull an object (hence they call it a 'tractor').

If an asteroid passes near the Earth, then the Earth's gravity will 'tractor' it into a new path... and at the same time the astoriod's gravity will change the Earth orbit as well. Keep in mind that due to the size difference, the asteroid will move miles, while Earth will move micro-fractions of an inch.

[LITU]

When I look at H. sapiens and the propensity of the species to devolve, I can't help but root for the asteroid as a means of saving our planet from it's most deadly infestation.

[Geauterre]

I write about this stuff - science fiction - and I can tell you it's nonsense. Extrapolating the kind of gravitic effect it would take to move such an object off its trajectory, given its mass and momentum would require a technology that is hitherto unknown in our science.

As usual though, NASA dreams on, obliging the twitter mentalities of ignorant politicians, and reaping the billions out of taxpayer pockets.

[jubal8]

Since you're an expert, can I ask you a question. Aren't these the same orbital mechanics calculations that space mission scientists use to place a lander on Mars or put Cassini, a bus-sized object, into orbit around Saturn? Different values to be sure, but different equations?

[KenGirard]

I'd love to know what name you write under. Would it be Geoff?

All masses produce gravity. These gravitational forces pull on other masses, changing the paths that both objects are following in the near frictionless conditions of space. Given the amount of distance we are talking about in space, a small change in direction can cause a compleat miss.

Diverting an object's path by 1/10,000 of a degree today will change by how many miles where that object will be 15 years in the future? That is what a gravity tractor is trying to do.

Think of the gravity tractor effecting the astoroid the same way that the wind effects the bullet of a marksman firing at a target from 3/4 of mile. If the marksman doesn't compensate for the wind he will miss the target entierly.