August 13, 2013
Push An Asteroid Into Earth Orbit?
A dozen small asteroids have orbits which make a nudge into an Earth Lagrange point doable..
By looking through the catalog of known asteroids, aerospace engineers have identified 12 candidates that we could reach out and capture using existing rocket technology.
These are smaller asteroids, probably too small (2 to 60 meters) to be useful for mining. So my take: don't bother. Why? Asteroid capture should be done entirely for profit.
I would rather NASA spent on developing systems to find more asteroids, especially since an asteroid could wipe out our civilization. The more asteroids discovered and studied with, say, orbital telescopes the more likely we'll find one that could be retrieved for profit.
We aren't going to sustain a major presence in space until we can make money doing it. Support for the US government's push to reach the Moon did not last long beyond the first Moon landing. A trip to Mars would produce the same result. So why bother? Only a profitable move into space will be sustained.
Randall Parker, 2013 August 13 10:20 PM
>I would rather NASA spent on developing systems to find more asteroids,
>could wipe out our civilization.
there is no chance we will be wiped by asteroid if only civilization is stopped by some other mean. There are just no asteroids of the same size (10 km) which wiped dinos.
there are probably several 1-km sized unknown PHA ( potentially hazardous asteroids ) which could kill 1 billion people in most worst case and which are about to be captured by current means within 5-10 years timeframe ( both ongoing catalina sky survey upgrade ( 3x search capabilities of current ) and completion of PanSTARRS will provide capabilities to find all 1km wide asteroids). Simulations give that within 10 years PanSTARRS alone is about to find more than 90% of all asteroids 300m size ( which can kill a small country - but the chance even if such asteroid hits earth 1/100th of serious damage, otherwise the damage is big, but not unlike we face with regular big earthquakes ). But PanSTARRS is not alone survey it currently finds about 1/4 of all new found asteroids ( might be 50% when PanSTARRS is 4 mirror telescope - still - not there are some other efforts ).
Large Synoptic Survey Telescope which is being build ( a site is prepared and mirrors were cast ) and will come online in 20s - will be capable to find 90%+ of asteroids 140 meters wide.
there two satellites which could add some information on asteroids canadian NeoSSAT which is currently in testing phase and europian 6 year mission to catalog stars ( but also is projected to find thousands of new asteroids ) which will be launched later the year. NASA also successfully tested new infrared sensor for the projected space telescope which will find 60% of all 100 meters+ asteroids within 4 years ( or 90% in two missions or 100 with Large Synoptic Survey Telescope ).
There was also call for proposals recently for ideas, so there could be some new things in pipeline.
so here it is possible to be more specific - what to make - speed up construction of Large Synoptic Survey Telescope , launch already designed telescope for 4 year missions ( or 3 4 year missions ), but the problem is that maybe you are not so interested in specifics here?
Why bother? I suspect the motive for NASA's proposal is less than innocent. They're on a track to be shown up by private industry. If they can convince investors that THEY are about to do what Planetary Resources is proposing to do, maybe they can kill Planetary Resources in the bud. Then abandon the program, no asteroid retrieval in the end, but NASA is spared a little embarrassment. THAT is what I think is going on here.
As far as NASA is concerned, I have lost faith in them but the idea of asteroid capture makes a lot of sense. It is cheaper to get the material from space, even if it is not as good then bring it up from Earth.
It's a first step, essentially practice for docking valuable space rocks prior to getting them down to the surface.
Well, the motive to "capture the culture" of the American pioneer in the Apollo program was to replace the nation of settlers with the nation of immigrants. So, indeed, why bother now that that purpose is a fiat accompli?
Well, one reason might be that there are enough viable survivors from the nation of settlers, after the tens of millions of demographic-death toll, urbanization, indoctrination and immigration infiltration, that if allowed to escape to a frontier they might, in the resulting quietism, wake up. Better to mop up the remnants.
That's why it might be a "good" idea to pump money into NASA.
"There are just no asteroids of the same size (10 km) which wiped dinos."
How do you know?
there are two approaches here
there are estimations of asteroid numbers by their sizes see for example here one estimation after WISE mission:
http://www.nasa.gov/mission_pages/WISE/multimedia/gallery/neowise/pia14734.html (you might search scientific papers of asteroid distributions ) and there are just no place for asteroids with sizes more than 4 km already since 2005 ( and none was found since ).
another one is simulation of observation coverage and asteroid visibility. It is just extremely difficult not to see an asteroid of such size with modern telescopes - it cannot escape. For km sized asteroids it is a little bit more difficult still PanSTARRS telescope can spot 80% of km sized asteroids in any orbit for the first 4 years of operation.
btw from estimation http://www.nasa.gov/mission_pages/WISE/multimedia/gallery/neowise/pia14734.html you might find that there are estimated 981 asteroids of km size and also there were 911 km sized discovered asteroids at the end of WISE mission.
Now - while http://neo.jpl.nasa.gov/stats/ has another metric to estimate discovered asteroids ( see textual note at the top of page ) but since beginning of 2011 when WISE stopped there were discovered ~40 new km sized asteroids.
So currently we know ~951 out of 981 (±19) km sized asteroids. Given that there is one PHA per 6-8 near earth objects we either know all km sized asteroids or almost all.
so for the biggest asteroids they are considering, what are the military implications? If the 1km or whatever size rock accidentally drops from the intended orbit downwards, will the impact be like a run-off-the-mill hydrogen bomb or something more significant?
1 km^3 of rock @ 2.5 g/cc = 2.5e18 kg
Coming in at a typical 35 km/s, E = ½mv² = 1.5e27 J
1 megaton = 4.2e15 J so that energy equals 360 teratons of TNT.
It could be a useful exercise even if there's no immediate payoff. I'd look at this as a practice run that we can learn from for the next time.
Michael, the good news is it takes a lot of energy to move a large asteroid around so one that is having its orbit altered can no more accidently hit the earth than I can accidently climb a mountain. If the rock had rockets on it powerful enough for some mass murdering criminal to purposely smack it into earth, then I'd be more worried about the rockets being launched at targets on earth as they would get here a lot quicker and leave little time for preparation or evacuation, even if we knew where they were going to hit.
Randall is dead on with his perspective. Why bother with a "stunt" asteroid capture? If it's science you want, it's much cheaper to visit and sample return some selected portions of larger objects, objects whose composition would yield ground truth (Heh) info related to deflection possibilities and future mining. NASA proposes this mission to justify its SLS Orion boondoggle development program which otherwise has no substantive purpose. We're best served if NASA gets out of vehicle development and focuses on space science and applied science advanced propulsion R&D. As Randall said, these NASA missions have no sustainability. Have we not seen that with post Apollo?
Philw, I'm not even sure of the value of a sample return mission given how so many asteroids are eager to visit us. A mission to determine the suitability of, or to try out deflection techniques might be more worthwhile. Not that a sample return mission would have no value, but there are other things I'd like to see investigated first. For example, examining the isotopic ratio of the carbon in the methane in mar's atmosphere could determine whether of not it is of biological origin. Now that is something I am very interested in knowing.
Things are beginning to get more interesting. Asteroids, gamma ray bursts, cosmic rays and clouds, and a sun that wants to take a vacation all of a sudden.
On the other hand, who needs a killer asteroid when they've got Obama?