Asteroid 2012 DA14 - Satellites most at risk

People seem to have forgotten about this asteroid which is going to pass extremely close to us in Feb 2013. Here's a video that examines which geostationary satellites it might impact.

Ah the new ELENIN just arrived...
How can they calculate that accurate to say satellites are in danger but it won´t hit earth

Originally posted by StareDad
Ah the new ELENIN just arrived...
How can they calculate that accurate to say satellites are in danger but it won´t hit earth

Look at the uncertainty region. Does it intersect earth? No:

Does it intersect geosynchronous satellites? Yes. Thus, a satellite collision is a possibility, but a collision with earth is not.

reply to post by ngchunter


Yeah, my question remains...but thank you for the try.

Originally posted by StareDad
reply to post by ngchunter

 

Yeah, my question remains...but thank you for the try.

I just explained it, if the uncertainty region doesn't overlap earth but it does overlap the satellites, then we know the satellites are potentially at risk but earth is not. What about that do you not understand?

reply to post by ngchunter


It´s more about you
I asked how can they calculate that precise (leaving the afterwards added % of failure alone).
I mean, I learned that computers work with integers and floatings. These floatings have a end precision when it comes to rounding errors.
Then comes the whole tail of other errors such as imaging system, distance calculation etc.
That was my question

Originally posted by StareDad
reply to post by ngchunter

 

It´s more about you

I asked how can they calculate that precise (leaving the afterwards added % of failure alone).
I mean, I learned that computers work with integers and floatings. These floatings have a end precision when it comes to rounding errors.
Then comes the whole tail of other errors such as imaging system, distance calculation etc.
That was my question

The limitation is not floating point errors, the astrometric measurements used to compute the monte carlo solutions only go out to a hundredth of an arcsecond in right ascension anyway.
www.minorplanetcenter.net...
Those measurements are generally only accurate to within half an arcsecond or so due to resolving limits of the telescope and blurring of the atmosphere, thus the uncertainty region is generated by producing a series of monte carlo solutions that deliberately introduce a bit of noise into the astrometric readings of up to half an arcsecond randomly. By repeating this many times over you end up with the uncertainty region showing you where the asteroid will be as well as where it is most likely to be within that region.

reply to post by ngchunter


Thank you very much for the kind explanation. So these are the final error quotes then? Wow, astonishing how precise they can calculate it, looking at the date and when it was found.

Originally posted by StareDad
reply to post by ngchunter

 

Thank you very much for the kind explanation. So these are the final error quotes then? Wow, astonishing how precise they can calculate it, looking at the date and when it was found.

I wouldn't call them final.

As the approach gets closer and closer the estimates will become more and more accurate.

.......and the refinements will get smaller and smaller. They have enough information now to determine that there is zero probability of impact with Earth.

So, will it be visible to the naked eye? I can see the space station when it passes over, and its less than 80 meters wide and about 100 meters long...this rock is about half that size...
Aaaand on that note, with three new astronaughts at the space station, where exactly will it be located when the rock passes by?

Originally posted by Xcouncil=wisdom
So, will it be visible to the naked eye? I can see the space station when it passes over, and its less than 80 meters wide and about 100 meters long...this rock is about half that size...
Aaaand on that note, with three new astronaughts at the space station, where exactly will it be located when the rock passes by?

Great questions. The asteroid will be much further away than the ISS, and it is also much less reflective than the ISS (which has reflective metallic surfaces). The ISS orbits somewhere between 330 km and 410 km above Earth; the asteroid will pass approximately 30,000 km above us. It will not be visible to the naked eye, but will be visible in any good binoculars or telescope. neo.jpl.nasa.gov...

Originally posted by wildespace

Originally posted by Xcouncil=wisdom
So, will it be visible to the naked eye? I can see the space station when it passes over, and its less than 80 meters wide and about 100 meters long...this rock is about half that size...
Aaaand on that note, with three new astronaughts at the space station, where exactly will it be located when the rock passes by?

Great questions. The asteroid will be much further away than the ISS, and it is also much less reflective than the ISS (which has reflective metallic surfaces). The ISS orbits somewhere between 330 km and 410 km above Earth; the asteroid will pass approximately 30,000 km above us. It will not be visible to the naked eye, but will be visible in any good binoculars or telescope. neo.jpl.nasa.gov...

Beat me to it, exactly right.

Couldn't the asteroid's estimated path be altered after crashing into a satellite or two or would it just plow through the satellites sending debris our way?

Sooo, whats to say this asteroid wouldnt bump into another asteroid and the trajectory changed?
Doesnt it still need to clear a few rocks yet????

Originally posted by Lil Drummerboy
Sooo, whats to say this asteroid wouldnt bump into another asteroid and the trajectory changed?
Doesnt it still need to clear a few rocks yet????

Real life is not star wars, inter-asteroid collisions are exceedingly rare. Out of the thousands upon thousands of asteroids we know of and track, only a very few collisions have been found. That's not an issue. Even if this rock were to experience a collision with an unknown second rock, the odds that it would administer delta-V in a direction that would lead to an earth collision is extremely unlikely and since we're barely over a month away from the close approach the delta-V required is getting high (and therefore the collision needed to produce it would most likely destroy a rock this small).

Originally posted by Phantasm
Couldn't the asteroid's estimated path be altered after crashing into a satellite or two or would it just plow through the satellites sending debris our way?

A collision with a satellite at close approach cannot cause the asteroid to then collide with earth; the delta-V required would be astronomically high since you would have to completely change the asteroid's trajectory at that point since the trajectory misses earth and apogee is essentially occurring at that moment. Likewise, the debris of the satellite would be scattered but would not be thrown "at earth."