
NASA and ESA are going to slam a spacecraft into an asteroid to deflect it - carlsborg
https://www.technologyreview.com/s/614330/were-going-to-slam-a-spacecraft-into-an-asteroid-to-try-to-deflect-it
======
fullstop
The asteroid will abruptly turn and fly into Venus.

~~~
rubbingalcohol
The asteroid's orbit will decay and will collide with its orbiting object,
breaking it into pieces and sending a much bigger chunk directly back at
Earth.

~~~
RandomBacon
In understand the first reference, but not yours. What's it from?

~~~
fullstop
I've just started Persepolis Rising, please don't spoil anything
rubbingalcohol!

~~~
rubbingalcohol
lol I've never even heard of that. I'm just a little fearful of playing games
with asteroids. Probably because I suck at Star Fox.

~~~
throwmeback
Do watch The Expanse though. The show is amazing, and I hope the books are
even better.

------
smoyer
"If it works, it will be the first time in history humans have physically
changed the orbital trajectory of a space-based object."

They could have done a bit better with this quote ... we change the orbit of
space-based objects all the time! So far, they've only been man-made space-
based objects though. One thing the article leaves out is whether Bruce Willis
will be on-board again.

~~~
mikelyons
I think that something manufactured on Earth is an Earth-based object.

------
skelet
Great to see NASA and ESA working together in this selfish era. The world
needs more collaboration between people.

~~~
dfsegoat
Like this?

An American, a Russian and the first Arab astronaut from the UAE all just
headed into space together:

[https://time.com/5686017/international-space-station-uae-
ast...](https://time.com/5686017/international-space-station-uae-astronaut/)

... I've always admired the capacity for various Space Agencies to put any
current (geo)political, social etc. issues aside in the pursuit of science.
This isn't a new thing, but you are right - we can all take a page from their
book.

------
keeperofdakeys
Another idea for deflecting an asteroid:

[https://en.wikipedia.org/wiki/Gravity_tractor](https://en.wikipedia.org/wiki/Gravity_tractor)

------
Causality1
Seems strange to have an observational cubesat on the first vehicle and still
launch a second vehicle to arrive five years later instead of building a
second cubesat into the first.

~~~
sverige
Stop trying to reduce their budget.

------
danmaz74
If you're curious about how big is the asteroid we'll target (from Wikipedi):
it's a moonlet orbiting another asteroid; "It measures approximately 0.17±0.03
kilometers in diameter compared to 0.75±0.1 kilometers for its primary"

No mention about mass though, maybe because we don't know what the asteroid is
made of?

~~~
forgotpwd16
Knowing the asteroid's composition isn't required to calculate the mass. This
can be derived by the orbit. So, the total mass of the binary system (main and
moonlet) is known, but the mass contribution of each isn't. Assuming though
that they have the same bulk density, M2/M1 = (D2/D1)^3 ~ 0.0116 and
considering Σ Mi = M, then M2 ~ 0.0115M.

~~~
danmaz74
Thank you. I searched better online, the total mass is estimated at 52.7
billion kg, so the mass of the moonlet should be around 606,000 metric tons.

------
sawaruna
Will this work without any Huge Materia?

~~~
Filligree
Yeah, but the asteroid might pause in its orbit for a couple months before
releasing hurricanes.

------
apacheCamel
Space is always so fascinating and unknown to me in so many ways. I've never
really thought about the endless amount of ways space could wind up killing
me, it just seems so far away from my daily life that I don't need to worry
about it. I really hope this experiment works for them, or they learn a good
bit from it, but I also really hope we never have to use it.

------
travisporter
Much more reasonable than NASA’s ARM which was cancelled
([https://www.nasa.gov/content/what-is-nasa-s-asteroid-
redirec...](https://www.nasa.gov/content/what-is-nasa-s-asteroid-redirect-
mission)). But I hope we bring it back

------
thiefmeister
> Get ready for humans to change the orbit of another rock in space for the
> first time in history

I don't understand. Change the orbit of another rock

and

for the first time in history.

How can changing an orbit of another rock be the first in history?

My english is not a native level.

~~~
Doxin
"Another" here doesn't mean we've done it before. You're supposed to interpret
it as "Change the orbit of _a_ rock".

I'm assuming "Another" refers to "A rock that is not earth." Though that does
seem rather confusing.

------
dskjbfsakljb
Hmmm. The vast majority of space object's orbits are stable enough in orbits
avoiding us:

1\. We wouldn't be here if it weren't the case 2\. They would have already
collided.

Do we really want to destabilize an otherwise random asteroid's orbit unless
it's certain it's on a collision course?

1\. There are millions (billions?) of other asteroids that come close to us.
What makes this one so special? Deflecting this one, even if the deflection
works with no unintended consequences, does nothing to improve our odds
against getting hit (P = P_one_asteroid * N_asteroids; N_asteroids - 1 ~
N_asteroids). 2\. If the deflection destabilizes the orbit, where will the
asteroid go but to a nice heafty attractor ?

The only value of this is if we're certain its on a collision course. But if
we are, then it too late to deflect!

~~~
Cthulhu_
First off, why wait until we have an actual emergency to test out a theory?

Second, your statement #2 is true, it caused a mass extinction event and
probably paved the way for humanity to evolve. If we however get hit by an
asteroid of that size again, chances are high that most of the population will
die out.

~~~
ehgshgshg
The Earth has already swept it's region of the solar system clean with prior
collisions causing the mass extinctions.

There are not an infinite amount of asteroids, and in large time frames you
can reduce their numbers. Therefore, we have a large hit once a century.
Large, but largely inconsequential (The Earth is empty. Try this: Pick random
coordinates and look them up on a map. Repeat. How long before you end up w/
10 km of an inhabited area?)

Theories are infinite, funds are not. This is an ineffective solution (we can
only deflect small and well predicted orbits) to an unlikely problem: mass
extinction from asteroids hasn't happened in a very long time (millions of
years) -> Bayesian inference -> very low probability of occurring _soon_. It
will happen. But in a millions years

Compare that with the plethora of reasons we might die out in the next 10, 20,
or 100 years.

~~~
nguoi
The last mass extinction event caused by an asteroid was probably only about
66 Mya, about 1% of the Earth's lifetime.

~~~
ehgshgshg
So very rare.

Mass extinctions, from your number, appear to be a once in a 132 Mya event.
[0]

Humans have been on Earth 0.1 Mya, 0.2Mya; statistically we'll be around for a
total of 0.2 to 0.4 Mya in total. [0][1]

Therefore, there is a 1-330 chance of the two time lines overlapping.

[0] Assuming the present time is random, I believe the best estimate of event
frequency is that we're in the middle of two occurrences; hence the doubling.
[1]I'm being generous here. I don't think we have 0.2 Mya left in us,
primarily because for the first time in history we have the ability to kill
ourselves off. Therefore the assumption that out present in at a random
position of the human experience used in [0] is invalid. Since we probably
only have 100 years left, that's a 1-1E6 possibility facing us.

------
sbmthakur
Can we shoot down distant asteroids with a missile?

~~~
ben_w
No, for much the same reasons that you can’t shoot down an incoming KE shell
fired at you from the main gun of a tank on a ridge half a mile above you with
a bang-snap you fire from a child’s elastic catapult.

Sure, technically asteroids come in many sizes, but for dangerous ones you are
talking about shooting a thing the size of a mountain that is falling towards
you in a way that makes it stop falling towards you.

------
env123
It'd be hilarious due to some universal physics that cannot be understood, the
asteroid slams into Earth due to the interference

~~~
raxxorrax
I think this particular rock is about 800m in diameter. That would probably
not kill us completely, just be the most catastrophic natural disaster in the
history of humanity.

But jokes aside, I think the probability of altering the orbit to hit the
earth practically non-existent, especially if you hit it when it is relatively
close. You would want to hit it when it is the furthest away from earth to
maximize your impact, so something > than 2AU or > than 300,000,000km.

------
hos234
Would pushing large enough asteroids into one another generate gravitational
waves?

~~~
forgotpwd16
Any form of acceleration generates gravitational waves. The point is how
strong they are. Two black holes sized ~200km (or ~30 solar masses) merging at
distance ~10000km would be detected through an interferometer by a shift in
one part in 1000, that is a change of ~2mm. Those are objects many order of
magnitudes more massive than asteroids. So you will get gravitational waves
but you wouldn't be able to detect them similar to not being able to detect
the waves responsible for the orbit decay of planets.

~~~
jcims
This is true but we’re detecting that type of interaction a billion lightyears
away. I bet if you did the stubby pencil work you would find that the
sensitivity is there. I just don’t think the search algorithms would find the
signature.

------
Moral_
Will this add a bunch of debris to the already crowded near earth space?

~~~
Retric
No, this is not in earth orbit.

~~~
fsloth
And the solar system is anyway full of flying gravel. The environmental impact
is similar if you went to an open mine pit and hammered at a small rock for a
while.

~~~
nighthawk648
I think the concern is that near earth orbit one day will be impassable
without some garbage collection.

The acceleration of objects in near earth orbit is vastly greater than the
particles from a mine. Space ships collaring with super fast particles in the
orbit could spell disaster for the spacecraft.

Hopefully we find ways to make the rock impact negligible if we ever get to
the stage of unable to leave orbit due to collisions with space particles (Not
saying subatomic particles I just mean debris)

~~~
marcosdumay
I don't think anybody shares that concern. Not even for LEO, where the wildest
fear is not being able to stay in a stable orbit there for years.

~~~
hoffs
Not exactly [https://www.nytimes.com/2019/04/02/world/asia/nasa-india-
spa...](https://www.nytimes.com/2019/04/02/world/asia/nasa-india-space-
debris.html)

~~~
nighthawk648
Thank you for this article! I would post kurgezstat video but their
credibility went down recently so NOPE

~~~
Retric
I think you’re both missing marcosdumay‘s point. If you just want to say go to
Mars then you can very quickly got far from earth and easily avoid space junk.
The IIS is huge and most days has no problem with space debris. It’s only when
you start talking about spending months and years in earth orbit that Kessler
syndrome becomes a real concern.

Put another way, if you had 1,000 tons of mass to spread around earth orbit it
would be difficult to effectively block rockets from leaving. Try to do the
same thing with random orbits and it’s even less of a concern.

~~~
nighthawk648
I think you are missing the point of years of space debris being added will
eventually cause Kessler syndrome to be a lot more accessible from short space
travel

------
kuroikyu
It's happening! I hope they make a movie out of it.

------
yummypaint
Would be nice if we could care this much about the actual ongoing mass
extinction event we are perpetuating on earth.

