typodupeerror

## ESA Selects Targets for Asteroid Deflection Test284

Vandil X writes "The European Space Agency has announced that it has selected two candidate asteroid targets for a planned mission to impact an asteroid in an attempt to deflect the asteroid off course by a measurable amount. The mission, dubbed "Don Quijote," will send two spacecraft to their final choice asteroid. One craft will impact the asteroid while the other will observe the asteroid before and after the collision. The mission craft and target selection are expected to be finalized sometime in 2007."
This discussion has been archived. No new comments can be posted.

## ESA Selects Targets for Asteroid Deflection Test

• #### Something wrong with p? (Score:1, Informative)

by Anonymous Coward on Monday September 26, 2005 @09:05PM (#13655526)
What's wrong with the good old p=mv (momentum)?
• #### Re:Something wrong with p? (Score:2, Informative)

<sketerpot@gmDEGASail.com minus painter> on Monday September 26, 2005 @09:31PM (#13655681)
Just use p = mv, where p and v are 3-dimensional vectors.
• #### Re:Fighting windmills? (Score:4, Informative)

<reformed.excon@gmail.com> on Monday September 26, 2005 @09:53PM (#13655768)
That's funny since the original text has it spelled Quixote: http://csdl.tamu.edu/cgi-bin/shuehu/qbrowse/qb?POR C=P&NO=1 [tamu.edu]

I wonder when they decided to change the spelling.
• #### Re:revised standard Don Quixote (Score:4, Informative)

on Monday September 26, 2005 @10:31PM (#13655916) Journal
...and a whole lot of F's to S's, so children could at least pronounce the words. Haven't you ever done a double-take when you've seen the word "Congrefs" written on a piece of parchment?

**wax on** It's not an F. What you see is the "long s". It's how they used to draw an S character since the days of Carolingian Minuscule, from which hand our "Times Roman" eventually derived. You'll note there was no crossbar on the letter in that form - the crossbar distinguished the "f" from the "long s". The form we take as "s" appeared only at the end of the word. Thus, "Congrefs" would have been pronounced "Congress". **wax off**

• #### Re:Something wrong with p? SIMPLE (Score:5, Informative)

on Monday September 26, 2005 @11:05PM (#13656022)
(p1 + p2)[)[initial]=(p1 + p2)[final]

Uh, we know the first two p(momentum, vector) values(and that's if we know the mass of the asteroid, which isn't necessarily true), but not the second two. In my math classes, we learned that was 1 equation (vector valued) and two unknown vectors. I don't think anyone can solve that, and no, conservation of kinetic energy won't work because the internal energy changes big time in most non-particle scale collisions. In Mechanics, many of our college educated comrades learned of a way to resolve this textbook documented issue with the simple aide of a constant e, which details the elasticity of the interaction. Unfortunately, e is not easy to determine through theory, and is also just a model (and a bad one at that), and therefore an experiment is usually called for (and usually a lot of them). 'Nuff said.

http://scienceworld.wolfram.com/physics/Collision. html [wolfram.com]
• #### Re:Fighting windmills? (Score:5, Informative)

on Monday September 26, 2005 @11:31PM (#13656141)
I wonder when they decided to change the spelling.

Change from Old Spanish to Modern Spanish. X had the "heh" sound (as in Mexico), but has transitioned to a "sh" sound (as in Ixtacihuatl)/"gs" sound as in explorar. Words have changed to reflect the new usage, but names proper names are blurry, so you will see Mexico, Mejico; Xavier, Javier; Quijote, Quixote
• #### Re:Something wrong with p? (Score:2, Informative)

<.moc.liamg. .ta. .onacrem.> on Monday September 26, 2005 @11:36PM (#13656155)
Someone brought up [slashdot.org] the Pioneer anomaly [wikipedia.org] over in the Voyager thread earlier today. Intesting stuff, proves Yogi knows what he's talking about.
• #### Re:The grants game (Score:5, Informative)

<ejkeever&nerdshack,com> on Tuesday September 27, 2005 @01:20AM (#13656438)
NASA's Deep Impact mission was against a comet. Because comets continually eject large amounts of gas and dust while they are inside Jupiter orbit, it is not possible to track the comet accurately enough to know what changes in it's course were caused by the impact and what was caused by the gas and dust normally ejected. Indeed, it's impossible to predict the exact path of short-period comets because of this.

By launching a projectile at an asteroid instead, we will know that any changes in the asteroid's trajectory were caused by our impactor because asteroids are inert and have otherwise very stable and predictable orbits.
• #### Re:Crash? (Score:2, Informative)

<cevkiv AT gmail DOT com> on Tuesday September 27, 2005 @02:27AM (#13656607) Journal
Just because you lack the information to accurately determine their future states does not mean they behave unpredictably.

I'd say the fact that I can't predict something's behaviour (accurately determine) makes it unpredictable, wouldn't you?

• #### Re:What happens... (Score:3, Informative)

on Tuesday September 27, 2005 @04:41AM (#13656896)
Is anyone else considering the possibility that this asteroid actually is on a collision course with Earth, and they don't want to panic us? Paranoia hats on, everyone.

Oh yeah, sure. ESA and NASA keep this collision secret because:

• They prefer to risk their lifes with a budget-quenching mission rather than make damn sure with 2,3 or more redundant missions.
• They don't want the funding they would get in face with such a collision

Also, this is ESA. There isn't nearly as much useless secrecy in Europe than in the USA.

• #### Re:you are giving me a book idea (Score:2, Informative)

on Tuesday September 27, 2005 @04:46AM (#13656902) Journal
Nah. Ugly, smelly women mostly cost as much as nonsmelly, nonugly women. In this case, you don't get what you pay for.
• #### Re:Fighting windmills? (Score:2, Informative)

on Tuesday September 27, 2005 @05:09AM (#13656939) Homepage

In modern Spanish, the gentleman's name is Don Quijote (the X was pronounced in the same way as J is pronounced now -- that's why Mexico, Texas and Oaxaca are pronounced as "Méjico", "Tejas" and "Oajaca" in Spanish).

And the reason for the naming is simple: one spacecraft (the Hidalgo -- Don Quijote himself) will ram the asteroid (a windmill) while the other one (Sancho) looks from afar.

• #### Re:Fighting windmills? (Score:2, Informative)

on Tuesday September 27, 2005 @05:49AM (#13657038) Homepage
And they could have spelled it correctly: Don Quixote.

Excuse me Sir. I think you are mistaking here.

It's a Spanish book [wikipedia.org] what you are referring to. The mission was conceived by spaniards [esa.int], and the main contractor is Spanish [deimos-space.com]. They have chosen to use the Spanish spelling: Don Quijote.

Save a little money each month and at the end of the year you'll be surprised at how little you have. -- Ernest Haskins

Working...