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Scientists Map Out How to Nudge Small Asteroids into Earth’s Orbit



 
 
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  #1  
Old September 4th 18, 12:29 AM posted to sci.space.policy
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Posts: 687
Default Scientists Map Out How to Nudge Small Asteroids into Earth’s Orbit

"The notion of an asteroid headed for Earth is typically seen as a bad omen.. On
the flip side, some scientists and entrepreneurs increasingly see this scenario
as a potential opportunity. Deliberately redirecting asteroids to our planet’s
vicinity could enable us to study them up close, or even mine them.

Given that these objects are packed with valuable resources, building a
collection of them nearby could spark major advances in spaceflight, to say
nothing of the scientific research that might result from easy access to these
extraterrestrial bodies.

A recent paper published in Acta Astronautica suggests that asteroids could be
captured in Earth’s orbit with aerobraking, a maneuver that uses atmospheric
drag to decelerate and position objects in stable trajectories around a planet.
Aerobraking has helped place interplanetary spacecraft in orbit around Mars and
Venus, and to slow down spacecraft returning to Earth.

Led by Minghu Tan, a PhD student at the University of Glasgow, the paper
immediately addresses the most obvious concern with this scenario: What if
there’s some mistake in the redirect process and an asteroid accidentally
impacts Earth? It’s bad enough that the dinosaurs were oblivious to their
doomsday space rock, but it would be especially embarrassing if we humans smack
ourselves in the face with one."

See:

https://motherboard.vice.com/en_us/a...o-earths-orbit
  #2  
Old September 4th 18, 02:18 AM posted to sci.space.policy
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Posts: 75
Default Scientists Map Out How to Nudge Small Asteroids into Earth’s Orbit

On Monday, September 3, 2018 at 7:29:47 PM UTC-4, wrote:
"The notion of an asteroid headed for Earth is typically seen as a bad omen. On
the flip side, some scientists and entrepreneurs increasingly see this scenario
as a potential opportunity. Deliberately redirecting asteroids to our planet’s
vicinity could enable us to study them up close, or even mine them.

Given that these objects are packed with valuable resources, building a
collection of them nearby could spark major advances in spaceflight, to say
nothing of the scientific research that might result from easy access to these
extraterrestrial bodies.

A recent paper published in Acta Astronautica suggests that asteroids could be
captured in Earth’s orbit with aerobraking, a maneuver that uses atmospheric
drag to decelerate and position objects in stable trajectories around a planet.
Aerobraking has helped place interplanetary spacecraft in orbit around Mars and
Venus, and to slow down spacecraft returning to Earth.

Led by Minghu Tan, a PhD student at the University of Glasgow, the paper
immediately addresses the most obvious concern with this scenario: What if
there’s some mistake in the redirect process and an asteroid accidentally
impacts Earth? It’s bad enough that the dinosaurs were oblivious to their
doomsday space rock, but it would be especially embarrassing if we humans smack
ourselves in the face with one."

See:

https://motherboard.vice.com/en_us/a...o-earths-orbit


Using aerobraking is a rather touchy affair. It implies a high
thrust impulse on the asteroid to begin the transfer orbit.

A small impulse to use gravitational capture allows the use of an
emergency escape engine to eject a failed capture.

Small vectoring to one of the L orbits and a mass limit rule
would be an alternative.
  #3  
Old September 4th 18, 03:19 AM posted to sci.space.policy
Sylvia Else
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Posts: 1,063
Default Scientists Map Out How to Nudge Small Asteroids into Earth’s Orbit

On 4/09/2018 9:29 AM, wrote:
"The notion of an asteroid headed for Earth is typically seen as a bad omen. On
the flip side, some scientists and entrepreneurs increasingly see this scenario
as a potential opportunity. Deliberately redirecting asteroids to our planet’s
vicinity could enable us to study them up close, or even mine them.

Given that these objects are packed with valuable resources, building a
collection of them nearby could spark major advances in spaceflight, to say
nothing of the scientific research that might result from easy access to these
extraterrestrial bodies.

A recent paper published in Acta Astronautica suggests that asteroids could be
captured in Earth’s orbit with aerobraking, a maneuver that uses atmospheric
drag to decelerate and position objects in stable trajectories around a planet.
Aerobraking has helped place interplanetary spacecraft in orbit around Mars and
Venus, and to slow down spacecraft returning to Earth.

Led by Minghu Tan, a PhD student at the University of Glasgow, the paper
immediately addresses the most obvious concern with this scenario: What if
there’s some mistake in the redirect process and an asteroid accidentally
impacts Earth? It’s bad enough that the dinosaurs were oblivious to their
doomsday space rock, but it would be especially embarrassing if we humans smack
ourselves in the face with one."

See:

https://motherboard.vice.com/en_us/a...o-earths-orbit


After the aerobraking pass, you need to raise its perigee quite a lot,
or it's just going to come back and burn up, either on the next pass, or
some subsequent pass.

Giving that we're talking about a hugely massive object, this seems a
big ask.

Sylvia.
  #4  
Old September 4th 18, 04:44 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Posts: 10,018
Default Scientists Map Out How to Nudge Small Asteroids into Earth's Orbit

wrote on Mon, 3 Sep 2018 18:18:21 -0700
(PDT):

On Monday, September 3, 2018 at 7:29:47 PM UTC-4, wrote:
"The notion of an asteroid headed for Earth is typically seen as a bad omen. On
the flip side, some scientists and entrepreneurs increasingly see this scenario
as a potential opportunity. Deliberately redirecting asteroids to our planets
vicinity could enable us to study them up close, or even mine them.

Given that these objects are packed with valuable resources, building a
collection of them nearby could spark major advances in spaceflight, to say
nothing of the scientific research that might result from easy access to these
extraterrestrial bodies.

A recent paper published in Acta Astronautica suggests that asteroids could be
captured in Earths orbit with aerobraking, a maneuver that uses atmospheric
drag to decelerate and position objects in stable trajectories around a planet.
Aerobraking has helped place interplanetary spacecraft in orbit around Mars and
Venus, and to slow down spacecraft returning to Earth.

Led by Minghu Tan, a PhD student at the University of Glasgow, the paper
immediately addresses the most obvious concern with this scenario: What if
theres some mistake in the redirect process and an asteroid accidentally
impacts Earth? Its bad enough that the dinosaurs were oblivious to their
doomsday space rock, but it would be especially embarrassing if we humans smack
ourselves in the face with one."

See:

https://motherboard.vice.com/en_us/a...o-earths-orbit


Using aerobraking is a rather touchy affair. It implies a high
thrust impulse on the asteroid to begin the transfer orbit.

A small impulse to use gravitational capture allows the use of an
emergency escape engine to eject a failed capture.


Except the rationale for using aerobraking is that you cannot paste a
big enough engine on a target asteroid to stick it in orbit without
using something like aerobraking to slow it down.


Small vectoring to one of the L orbits and a mass limit rule
would be an alternative.


Again, how big an engine with how much fuel do you think you can lift
up to an asteroid? Personally, I prefer 'lithobraking' by tossing
them into a lunar crater and then sending a crew in to mine out the
content by conventional means. Nobody gets hurt and it's easier than
mining and smelting the things in deep space.


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden
  #5  
Old September 4th 18, 11:44 AM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 2,307
Default Scientists Map Out How to Nudge Small Asteroids into Earth?s Orbit

In article ,
ess says...

On 4/09/2018 9:29 AM,
wrote:
"The notion of an asteroid headed for Earth is typically seen as a bad omen. On
the flip side, some scientists and entrepreneurs increasingly see this scenario
as a potential opportunity. Deliberately redirecting asteroids to our planet?s
vicinity could enable us to study them up close, or even mine them.

Given that these objects are packed with valuable resources, building a
collection of them nearby could spark major advances in spaceflight, to say
nothing of the scientific research that might result from easy access to these
extraterrestrial bodies.

A recent paper published in Acta Astronautica suggests that asteroids could be
captured in Earth?s orbit with aerobraking, a maneuver that uses atmospheric
drag to decelerate and position objects in stable trajectories around a planet.
Aerobraking has helped place interplanetary spacecraft in orbit around Mars and
Venus, and to slow down spacecraft returning to Earth.

Led by Minghu Tan, a PhD student at the University of Glasgow, the paper
immediately addresses the most obvious concern with this scenario: What if
there?s some mistake in the redirect process and an asteroid accidentally
impacts Earth? It?s bad enough that the dinosaurs were oblivious to their
doomsday space rock, but it would be especially embarrassing if we humans smack
ourselves in the face with one."

See:

https://motherboard.vice.com/en_us/a...o-earths-orbit


After the aerobraking pass, you need to raise its perigee quite a lot,
or it's just going to come back and burn up, either on the next pass, or
some subsequent pass.


The article doesn't say how the perigee would be raised. Unless they're
planning on using a lunar flyby, I don't see how you can do this without
a sufficiently large rocket engine.

I'm not an expert in orbital mechanics but I do agree you have to
somehow raise the perigee after the aerobraking pass(es) is(are) done.

Giving that we're talking about a hugely massive object, this seems a
big ask.


Yep. I'd rather drop Kuiper belt objects on Mars myself. No danger to
humans on earth. :-)

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #6  
Old September 4th 18, 04:38 PM posted to sci.space.policy
[email protected]
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Posts: 687
Default Scientists Map Out How to Nudge Small Asteroids into Earth?s Orbit

Maybe it would be safer to just grab the "mini moons" that Earth captures
periodically:

"But new research has unearthed (...unmooned?) evidence that our planet
occasionally captures “mini-moons” every once in a while. These tiny asteroids
zoom around our planet as temporary natural satellites."

See:

https://bigthink.com/mike-colagrossi...ou-might-think

  #7  
Old September 5th 18, 06:18 AM posted to sci.space.policy
William Elliot[_4_]
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Posts: 86
Default Scientists Map Out How to Nudge Small Asteroids into Earth?sOrbit

Maybe it would be safer to just grab the "mini moons" that Earth
captures periodically:

"But new research has unearthed (...unmooned?) evidence that our
planet occasionally captures “mini-moons” every once in a while.
These tiny asteroids zoom around our planet as temporary natural
satellites."


Wouldn't it be easier since it's already in Earth capture?

See:
https://bigthink.com/mike-colagrossi...ou-might-think


  #8  
Old September 5th 18, 08:15 AM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default Scientists Map Out How to Nudge Small Asteroids into Earth?s Orbit

William Elliot wrote on Tue, 4 Sep 2018 22:18:35
-0700:

Maybe it would be safer to just grab the "mini moons" that Earth
captures periodically:

"But new research has unearthed (...unmooned?) evidence that our
planet occasionally captures mini-moons every once in a while.
These tiny asteroids zoom around our planet as temporary natural
satellites."


Wouldn't it be easier since it's already in Earth capture?


Easier, no doubt, but you'd kind of like to pick something worth
mining and relying on random chance is unlikely to deliver that very
often.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw
  #9  
Old September 5th 18, 09:18 PM posted to sci.space.policy
Alain Fournier[_3_]
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Posts: 548
Default Scientists Map Out How to Nudge Small Asteroids into Earth?sOrbit

On Sept./4/2018 at 06:44, Jeff Findley wrote :
In article ,
ess says...

On 4/09/2018 9:29 AM,
wrote:
"The notion of an asteroid headed for Earth is typically seen as a bad omen. On
the flip side, some scientists and entrepreneurs increasingly see this scenario
as a potential opportunity. Deliberately redirecting asteroids to our planet?s
vicinity could enable us to study them up close, or even mine them.

Given that these objects are packed with valuable resources, building a
collection of them nearby could spark major advances in spaceflight, to say
nothing of the scientific research that might result from easy access to these
extraterrestrial bodies.

A recent paper published in Acta Astronautica suggests that asteroids could be
captured in Earth?s orbit with aerobraking, a maneuver that uses atmospheric
drag to decelerate and position objects in stable trajectories around a planet.
Aerobraking has helped place interplanetary spacecraft in orbit around Mars and
Venus, and to slow down spacecraft returning to Earth.

Led by Minghu Tan, a PhD student at the University of Glasgow, the paper
immediately addresses the most obvious concern with this scenario: What if
there?s some mistake in the redirect process and an asteroid accidentally
impacts Earth? It?s bad enough that the dinosaurs were oblivious to their
doomsday space rock, but it would be especially embarrassing if we humans smack
ourselves in the face with one."

See:

https://motherboard.vice.com/en_us/a...o-earths-orbit


After the aerobraking pass, you need to raise its perigee quite a lot,
or it's just going to come back and burn up, either on the next pass, or
some subsequent pass.


The article doesn't say how the perigee would be raised. Unless they're
planning on using a lunar flyby, I don't see how you can do this without
a sufficiently large rocket engine.


If you can nudge it enough to get it to do aero-braking, it shouldn't be
a problem to raise the perigee. One can imagine an extreme case where
the asteroid was going to pass 200 km above Earth's surface and you can
just barely nudge a little lower for aero-braking and then aren't able
to raise the perigee fast enough. But a big asteroid being on such a
trajectory isn't very likely. And those deciding to capture it being
smart enough to be able to nudge into the atmosphere, yet too stupid to
notice the danger isn't likely either. (People too stupid to see the
danger aren't hard to find, it's the combination with smart enough to be
able to nudge it that isn't likely.)

So I wouldn't be too scared about that.

Another thing that could be a problem is that you could mess up the
atmosphere if you do this with a big asteroid.

Personally, I would prefer doing a capture by selenic gravity assist.

I'm not an expert in orbital mechanics but I do agree you have to
somehow raise the perigee after the aerobraking pass(es) is(are) done.


I would expect that for a somewhat big asteroid, there would be several
aero-braking passes and that you would do small tweaks to the orbit
after each pass.


Alain Fournier
  #10  
Old September 6th 18, 02:13 AM posted to sci.space.policy
Sylvia Else
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Posts: 1,063
Default Scientists Map Out How to Nudge Small Asteroids into Earth?sOrbit

On 6/09/2018 6:18 AM, Alain Fournier wrote:
On Sept./4/2018 at 06:44, Jeff Findley wrote :
In article ,
ess says...

On 4/09/2018 9:29 AM,
wrote:
"The notion of an asteroid headed for Earth is typically seen as a
bad omen. On
the flip side, some scientists and entrepreneurs increasingly see
this scenario
as a potential opportunity. Deliberately redirecting asteroids to
our planet?s
vicinity could enable us to study them up close, or even mine them.

Given that these objects are packed with valuable resources, building a
collection of them nearby could spark major advances in spaceflight,
to say
nothing of the scientific research that might result from easy
access to these
extraterrestrial bodies.

A recent paper published in Acta Astronautica suggests that
asteroids could be
captured in Earth?s orbit with aerobraking, a maneuver that uses
atmospheric
drag to decelerate and position objects in stable trajectories
around a planet.
Aerobraking has helped place interplanetary spacecraft in orbit
around Mars and
Venus, and to slow down spacecraft returning to Earth.

Led by Minghu Tan, a PhD student at the University of Glasgow, the
paper
immediately addresses the most obvious concern with this scenario:
What if
there?s some mistake in the redirect process and an asteroid
accidentally
impacts Earth? It?s bad enough that the dinosaurs were oblivious to
their
doomsday space rock, but it would be especially embarrassing if we
humans smack
ourselves in the face with one."

See:

https://motherboard.vice.com/en_us/a...o-earths-orbit



After the aerobraking pass, you need to raise its perigee quite a lot,
or it's just going to come back and burn up, either on the next pass, or
some subsequent pass.


The article doesn't say how the perigee would be raised. Unless they're
planning on using a lunar flyby, I don't see how you can do this without
a sufficiently large rocket engine.


If you can nudge it enough to get it to do aero-braking, it shouldn't be
a problem to raise the perigee. One can imagine an extreme case where
the asteroid was going to pass 200 km above Earth's surface and you can
just barely nudge a little lower for aero-braking and then aren't able
to raise the perigee fast enough. But a big asteroid being on such a
trajectory isn't very likely. And those deciding to capture it being
smart enough to be able to nudge into the atmosphere, yet too stupid to
notice the danger isn't likely either. (People too stupid to see the
danger aren't hard to find, it's the combination with smart enough to be
able to nudge it that isn't likely.)


A small nudge a long way out can be enough to direct it towards the
Earth. But after the aerobraking, you don't have that option. You need
to raise its perigee quite a lot.

So I wouldn't be too scared about that.

Another thing that could be a problem is that you could mess up the
atmosphere if you do this with a big asteroid.

Personally, I would prefer doing a capture by selenic gravity assist.

I'm not an expert in orbital mechanics but I do agree you have to
somehow raise the perigee after the aerobraking pass(es) is(are) done.


I would expect that for a somewhat big asteroid, there would be several
aero-braking passes and that you would do small tweaks to the orbit
after each pass.


Alain Fournier


 




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