Slashdot Mirror
ESA Plans Test of Asteroid Defense System
vinlud writes "It has been announced by Dutch television ESA has chosen the Don Quijote programme to investigate the possibilities of altering the collision course of asteroids heading for Earth. The program, selected among five other studies, contains two spacecraft: Hidalgo and Sancho. Hidalgo will impact an asteroid of approximately 500 m diameter at a relative speed of at least 10 km/s while Sancho will retreat to a safe distance to observe the impact. An animation of the mission sequence (6.49 Mb) can be downloaded from here."
What's important is a very efficient backup of slashdot so I can still post in the case of a continent size meteor hitting earth.
I RTFA (however, I'm not new here!) and it seems all the other five studies were about observation only missions. This one is the only one to propose an actual 'impact'.
It's definitively more exciting but I wonder if it's not too hard to make such a millions miles away 'bull's eye'. 500 m in diameter is pretty small at this distance...
Iraq: war to save the U
"The full original title was El ingenioso hidalgo don Quixote de la Mancha. The adjective "quixotic," meaning "idealistic and impractical," derives from his name, and the expression "tilting at windmills" comes from his story."
The owls are not what they seem
-S
--- What parts of "shall make no law", "shall not be infringed", and "shall not be violated" don't you understand?
... yes I know, space is big... [grin]
Simon
Physicists get Hadrons!
...is to send Ben Affleck and Bruce Willis to the asteroid. One could make an animation of this, but it might result in a god-awful, 2-hour-long mistake.
These "asteroid defense" systems are lies told by weapons makers. They are designed to be expensive systems that can be pointed at the Earth. When the "missile defense" lies (eg. that they work) fail, as they always have in Europe, weapons makers turn to another irrational fear: asteroids. The odds of an asteroid damaging Europe are so much lower than many other preventable crises that the entire sham is transparent. The odds of AIDS killing millions is much higher, and more preventable. The odds of climate change killing millions are also much higher. The odds of a generation of people learning to watch TV rather than learning to read or think are much higher. There are known solutions to these likely crises that will cost less, and benefit much more. But they don't play on the kind of irrational fear that lets governments spend billions of people's money without accountability. So we'll pay for these lies once when we fund the sham, and again when the real threats come home to roost.
--
make install -not war
Guess we are doomed to die by hunger, terrorism, violent climate shift, war or MPAA.
I was really betting it would be an asteroid.
[ I can not bring myself to believe that if knowledge presents danger, the solution is ignorance ] -- Isaac Asimov
Try it out here.
is this just a hip way to repackage missile defense testing so that nobody gets mad?
Better link, maybe?
Beware: In C++, your friends can see your privates!
They work in all SI units. So, no conversions. Perhaps that's why Ariane is reliable.
Panurge has posted for the last time. Thanks for the positive moderations.
Perhaps the most famous part of this book is when Don Quixote gallantly charged at windmills, while Sancho watched. In his troubled mind, The windmills were evil Giants, which he sought to destroy to win the favors of his sweethart Dulcinea, wich is a very accurate depiction of what the program is supposed to do.
I find that the depiction, regardless of the obvious fact that in the book it was a hopeless cause; is a romantic metaphore, rather than an endorsement of failure, poor engineering or idealistic but unreachable goals.
As a side note, this book (El ingenioso Hidalgo, Don Quixote de la Mancha) is to the Spanish Language as The Count of Montecristo is to French, Luther's New testament translation is to German, and the works of Shakespeare are to English.
*shower*
But Neo is The One!
Show me on the doll where his noodly appendage touched you.
I can see that most slashdotters are trolling on the actual mission of the spaceships. Their purpose is to impact the asteroid to determine its composition, structure, ect. to then, determine an appropiate course of action.
And the names do fit. They fit because Don Quijote tried to bring back the idealized lifestyle of chivalry. His desire was to protect the good cause and perhaps slay a dragon or two in the way. He was mocked by people because they believed such perils were nonexistent. Just like we mock this far fetched perhaps, but still necesary project that aims to be our first line of defense in case of a possible, if not improbable event.
I fail to see how people can criticize this and yet run SETI at home on their computers.
Godspeed Don Quijote, and Sancho Pansa, I for once, am gratefull of your so much needed lunacy.
Assuming that the Hildalgo probe masses in at 25 kg (the same as Sancho - it might be less) and is moving at 10km/sec and assuming the asteroid has a density of 3g/cc (giving a mass of 4x10^10 kg, and if the probe is absorbed into the asteroid and no material is lost from the asteroid, then the change of velocity for the asteroid will be about 6x10^-9 km/sec.
For comparison, the asteroid probably has a velocity somewhere on the order of 5-10km/sec.
If the asteroid and probe hit head on with both having a velocity (relative to the sun) of 10km/sec, then you can double the change to 1.2x10^-8 km/sec
It's probably a good idea to check my work. Here's how I did the calculation:
Let m1 be the probe and m2 be the asteroid.
v(center of mass)=(m1*v1+m2*v2)/(m1+m2). v2=0 for this reference frame and m1+m2 essentially equals m2. Since we're in the reference frame of the asteroid being stationary, the combination of probe and asteroid will still have the same velocity for the center of mass.
I hope I didn't botch this estimate....
This sig seemed like a good idea at the time....
As a side note, this book (El ingenioso Hidalgo, Don Quixote de la Mancha) is to the Spanish Language as The Count of Montecristo is to French, Luther's New testament translation is to German, and the works of Shakespeare are to English.
As a Frenchman, I can tell you that while Montecristo is certainly the best book written by Dumas and probably in the fifty most important French books written, it is not "The Book". That honour would probably go to Victor Hugo's "Les Misérables".
I'm pleased by the naming choice BTW - it shows some humour and imagination, particularly with having Sancho stay behind and watch... they may be top notch engineers and scientists, but they have read their classics and can joke about their work. I like that.
What do you know about World Politic? Find out in this quiz
Not only does it accurately represent the potential effectiveness of this particular program, but also the necessity for an asteroid defense program in general. But I suspect the technology could be useful someday, likely for something other than the defense of the Earth from asteroids.
Sure one can question the wisdom of altering the course of an asteroid that is currently not on a course to earth as there is a risk that the new course might be a problem. Except that it would be reasonable to assume that the people at ESA have thought of this too.
The trajectories of space objects are something we actually understand really really well. It is simple math and the bigger objects have had their path calculated very accuratly centuries ago.
If we follow the advice of people like the above poster the human race would still be stuck up a tree worried about the dangers of the forest floor. Luckily we didn't and some of the monkeys got eaten but others survived and thrived.
MMO Quests are like orgasms:
You may solo them, I prefer them in a group.
The mission has a very high scientific value, but it will also help in testing technologies required for future deflection missions and raise interest in people for space exploration. The mission will in particular: measure the mass of the asteroid, the ratio of the moments of inertia and the low order harmonics of its gravity field. model the asteroid shape before and after the impact, to detect changes (if any). determine the asteroid internal structure, especially the size the main solid pieces, the average particle size and thickness of regolith and of the debris layers in the space left between the main pieces. constrain the mechanical properties of the asteroid material. measure the orbital deflection of the asteroid as a result of the impact of Hidalgo measure the asteroid rotation state before and immediately after the impact. detect the dissipation of the non-principal axis rotation after the impact. determine the asteroid large scale mineralogical composition.
SHE does throw dice.
It's about time our species started putting together and testing serious contingency plans against this sort of catastrophe.
This is essentially the question about the "stability of the solar system".
:)
:)
Google for that, or if you're too lazy to do it, here is a very short summary of what you can get by reading a bit:
- According to newton, every body with mass sees a force from each other body. A so called N-body-problem. (You should know that already =:)
- The orbits of all gravitating bodies (sun, planets, moons, asteroids, spacecraft etc.) in the solar system are chaotic, i.e. a small change (for example a displacement in the estimated position) will grow exponentially into a big change, maybe the crash
of two objects.
- BUT: The orbits may be bounded. I.e. they wobble in a chaotic way, but do not cross certain values. Of course, everyone hopes that this is the case
Now, earth remained relatively impact free for the past billions of years, i.e. the past billions of numbers of orbits around the sun!
- "relatively" since there are many impact craters on earth today, you can even visit some of them
But no object the size of a small moon impacted earth, else we would not be here.
Of course, people think about the reason why earth orbits so undisturbed since a long time.
There're models that describe the more massive bodies in the solar system (jupiter, saturn) as vacuum cleaners for asteroids. But don't ask me about that, I'm not a scientist (yet), just a student.
There is no reason to believe that the current system will be stable or that starting rockets spaceprobes or even walking around on earth (since you're also one of the above-mentioned bodies!) won't change if saturn and jupiter crash in a billion years!
Here are some odds and probablities as compiled by the oddities who write The Edge for The Oregonian (Portland, OR newspaper). Short version: it is actually more likely that the Earth will be smacked by a large asteroid in your lifetime than you becoming a professional athelete.
And remember, before you try to beat the odds, make sure you can survive the odds beating you.
Basicly we don't know enuf
Ah, thank you Mr. Hume, for destroying philosophy, and thank you modern education, for destroying poor Grimace1975's ability to spell.
Just because you do not know, doesn't cast doubt on the validity of the science behind this. It just means that YOU'RE ignorant.
I want to delete my account but Slashdot doesn't allow it.
Impact Effects Robert Marcus, H. Jay Melosh, and Gareth Collins
Your Inputs:
Distance from Impact: 100.00 km = 62.10 miles
Projectile Diameter: 500.00 m = 1640.00 ft = 0.31 miles
Projectile Density: 3000 kg/m3
Impact Velocity: 10.00 km/s = 6.21 miles/s
Impact Angle: 45 degrees
Target Density: 3000 kg/m3
Target Type: Competent Rock or saturated soil
Major Global Changes:
The Earth is not strongly disturbed by the impact and remains intact.
The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
The impact does not shift the Earth's orbit noticeably.
Energy: 9.82 x 1018 Joules = 2.35 x 10^3 MegaTons TNT
The average interval between impacts of this size somewhere on Earth is 4.3 x 10^4 years
Crater Size:
Transient Crater Diameter: 4.59 km = 2.85 miles
Final Crater Diameter: 5.63 km = 3.50 miles
The crater formed is a complex crater.
Thermal Radiation: Time for maximum radiation: 0.43 seconds after impact
Visible fireball radius: 3.5 km = 2.2 miles
The fireball appears 7.9 times larger than the sun
Thermal Exposure: 3.60 x 104 Joules/m2
Duration of Irradiation: 6 seconds
Radiant flux (relative to the sun): 6.5
Seismic Effects:
The major seismic shaking will arrive at approximately 20.0 seconds.
Richter Scale Magnitude: 6.9
Mercalli Scale Intensity at a distance of 100 km:
VI. Felt by all. Many frightened and run outdoors. Persons walk unsteadily. Windows, dishes, glassware broken. Knickknacks, books, etc., off shelves. Pictures off walls. Furniture moved or overturned. Weak plaster and masonry D cracked. Small bells ring (church, school). Trees, bushes shaken (visibly, or heard to rustle).
VII. Difficult to stand. Noticed by drivers of motor cars. Hanging objects quiver. Furniture broken. Damage to masonry D, including cracks. Weak chimneys broken at roof line. Fall of plaster, loose bricks, stones, tiles, cornices (also unbraced parapets and architectural ornaments). Some cracks in masonry C. Waves on ponds; water turbid with mud. Small slides and caving in along sand or gravel banks. Large bells ring. Concrete irrigation ditches damaged.
Masonry C. Ordinary workmanship and mortar; no extreme weaknesses like failing to tie in at corners, but neither reinforced nor designed against horizontal forces.
Masonry D. Weak materials, such as adobe; poor mortar; low standards of workmanship; weak horizontally.
Ejecta: The ejecta will arrive approximately 144.2 seconds after the impact.
At your position the ejecta arrives in scattered fragments
Average Ejecta Thickness: 4.6 mm = 0.1822 inches
Mean Fragment Diameter: 3.5 cm = 1.37 inches
Air Blast:
The air blast will arrive at approximately 333.3 seconds.
Peak Overpressure: 19232.2 Pa = 0.1923 bars = 2.7310 psi
Max wind velocity: 38.2 m/s = 85.4 mph
Sound Intensity: 86 dB (Loud as heavy traffic)
So let's see - you're 100 km away - first you experience a 6.9 earthquake, and the red hot 4.6mm fragments arrive 144 seconds later? Great - that's like 250 km per hour... Nice. Anyone in the open is DEAD, and your house might not survive that either. Then after being weakened by a major earthquake and a barrage of highspeed rocks, an 86 mph wind comes to visit.
Great. Sounds pretty crappy to me. I doubt that it would be the end of the world (Except for LA, but who cares?) but I think that even a smallish rock like that would produce some MAJOR damage, and should be avoided at all costs - alomst as much as voting for GW should be avoided.
RS
Shoes for Industry. Shoes for the Dead.
Disintegrate? Where the hell did you get THAT idea from? "Course collection" is what this thing IS doing, it's not Bruce Willis with nuclear bomb.
You don't have much of a change disintegrating 500m asteroid by hitting it with a probe weighting few hundred kilos unless you're doing the ramming at relativistic speeds.