Asteroid Forced To Orbit Moon & Miss Earth

[lubricatosaurus]

Why hasn't this been done sooner?
A big asteroid hitting earth is kinda a big deal you'd think.
I guess we're too busy trying to clean up terrorist atrocities around the world that we're not focusing on actual planetary defense.

"The robotic mission also will demonstrate planetary defense techniques to deflect dangerous asteroids and protect Earth if needed in the future. NASA will choose an asteroid mass for capture with a size and mass that cannot harm the Earth, because it would burn up in the atmosphere. In addition to ensuring a stable orbit, redirecting the asteroid mass to a distant retrograde orbit around the moon also will ensure it will not hit Earth."

https://www.nasa.gov/content/what-is-nasa-s-asteroid-redirect-mission

I'd like to know how much fuel burn and thrust they will need to actually put the asteroid in orbit around our own moon. Cool mission. Bruce Willis wants to ride along.

 

[Wolf359]

If you actually do the math, the cost benefit analysis isn't quite there yet. There's a very small chance that anything would hit the earth. You basically calculate the odds of that happening and the damage it would do and come up with a number of the cost divided by the odds of it happening. Sorta like do you buy flood insurance if your house is on a hill/mountain and nowhere near water?

 

[buster]

"The dinosaurs never saw that asteroid coming. What's our excuse?" - NDT.

 

[Shannow]

If you've got a android phone, download the "simple rocket" app.

Make a few rockets, get them into orbit, get them out of orbit, then have a bit of a think about how much would be required to move something significant...and how much fuel would be required to get the fuel up there.

It's a fun little app.

 

[lubricatosaurus]

Originally Posted By: Wolf359
If you actually do the math, the cost benefit analysis isn't quite there yet. There's a very small chance that anything would hit the earth. You basically calculate the odds of that happening and the damage it would do and come up with a number of the cost divided by the odds of it happening. Sorta like do you buy flood insurance if your house is on a hill/mountain and nowhere near water?


Tell that to South Carolinians right now.
http://www.usatoday.com/story/weather/2015/10/05/south-carolina-flooding-climate-change/73385778/
.... and all the other 0.1% chance flood events in the USA....... hmmmmm

All it takes is one.

 

[Wolf359]

You are talking about odds that are several orders of magnitude apart. Odds of a good asteroid hitting the earth is about one in a million years. No one has actually been hit by one in the last 1000 years.

You are more likely to win powerball, get killed because you're not wearing a seatbelt, get cancer, have a hearth attack etc than being killed by an asteroid.

 

[MolaKule]

Quote:
I'd like to know how much fuel burn and thrust they will need to actually put the asteroid in orbit around our own moon. Cool mission. Bruce Willis wants to ride along.


Much depends on the size (mass) of the asteroid and it's vectorial velocities, but it would be immense.

An alternative approach is to explode a fusion weapon on or near it and break it up into smaller masses, where most of the smaller masses would most likely burn up in the atmosphere before they could hit the Earth's surface.

 

[ecotourist]

Originally Posted By: MolaKule
An alternative approach is to explode a fusion weapon on or near it and break it up into smaller masses, where most of the smaller masses would most likely burn up in the atmosphere before they could hit the Earth's surface.


What happens when there is an explosion in space, when there is no atmosphere to push around?

 

[sleddriver]

Quote:
NASA plans to launch the ARM robotic spacecraft at the end of this decade. The spacecraft will capture a boulder off of a large asteroid using a robotic arm. After an asteroid mass is collected, the spacecraft will redirect it to a stable orbit around the moon called a “Distant Retrograde Orbit.” Astronauts aboard NASA's Orion spacecraft, launched from a Space Launch System (SLS) rocket, will explore the asteroid in the mid-2020s.


This is far from what the headline, and OP, might suggest. Further, it's MUCH farther away from actually redirecting the whole asteroid itself into a lunar orbit, that might just be moving along at > Mach20....

 

[MolaKule]

Originally Posted By: ecotourist
Originally Posted By: MolaKule
An alternative approach is to explode a fusion weapon on or near it and break it up into smaller masses, where most of the smaller masses would most likely burn up in the atmosphere before they could hit the Earth's surface.


What happens when there is an explosion in space, when there is no atmosphere to push around?


The heat from the explosion would heat up the internal gasses, turn the ices into steam, and cause an internal pressure rise within the asteroid fracturing it.

 

[Wolf359]

Originally Posted By: ecotourist
Originally Posted By: MolaKule
An alternative approach is to explode a fusion weapon on or near it and break it up into smaller masses, where most of the smaller masses would most likely burn up in the atmosphere before they could hit the Earth's surface.


What happens when there is an explosion in space, when there is no atmosphere to push around?


You don't really need an atmosphere for a nuclear explosion. The sun is a fusion reaction and operates fine without any atmosphere.

 

[bruno]

Look up the Siberian strike of a century ago . Lucky it hit where it did ... a small change in its orbit could have wiped out a city .

 

[SteveSRT8]

Originally Posted By: ecotourist
Originally Posted By: MolaKule
An alternative approach is to explode a fusion weapon on or near it and break it up into smaller masses, where most of the smaller masses would most likely burn up in the atmosphere before they could hit the Earth's surface.


What happens when there is an explosion in space, when there is no atmosphere to push around?


Seems the effects would actually be more widespread, as the atmosphere dampens the explosion...

 

[lubricatosaurus]

Originally Posted By: sleddriver
Quote:
NASA plans to launch the ARM robotic spacecraft at the end of this decade. The spacecraft will capture a boulder off of a large asteroid using a robotic arm. After an asteroid mass is collected, the spacecraft will redirect it to a stable orbit around the moon called a “Distant Retrograde Orbit.” Astronauts aboard NASA's Orion spacecraft, launched from a Space Launch System (SLS) rocket, will explore the asteroid in the mid-2020s.


This is far from what the headline, and OP, might suggest. Further, it's MUCH farther away from actually redirecting the whole asteroid itself into a lunar orbit, that might just be moving along at > Mach20....


Great point to make. My headline was misleading. Title only allows limited letters in it. &, The wording in the NASA text should be "the asteroid sample mass multi-ton boulder in the mid-2020's"
Still impressive since they are saying it will weigh >4,000 lbs, blasting it out of there and redirecting the boulder to lunar orbit somehow.

 

[lubricatosaurus]

Originally Posted By: Wolf359
You are talking about odds that are several orders of magnitude apart. Odds of a good asteroid hitting the earth is about one in a million years. No one has actually been hit by one in the last 1000 years.

You are more likely to win powerball, get killed because you're not wearing a seatbelt, get cancer, have a hearth attack etc than being killed by an asteroid.


Wrong again you are. You must not have ever heard of Tunguska 1908 explosion: "The Last Massive Exploding Meteor Hit Earth in 1908, Leveling 800 Square Miles of Forest .. In 1908, a meteor exploding in mid-air released the energy equivalent to "185 Hiroshima bombs"".

And as long ago as 2013 (back when dinosaurs roamed the earth???): "Early this morning in Russia, when a meteor broke up a few dozen kilometers above ground, its supersonic flight and mid-air death generated shock waves that rattled houses, broke windows, and sent dozens to the hospital. The meteor’s break-up released energy equivalent to a few hundred thousand tons of TNT.."

And another whopper from the age of the dinosaurs

all the way back 80k years ago:

 

[lubricatosaurus]

Originally Posted By: ecotourist
What happens when there is an explosion in space, when there is no atmosphere to push around?
I'd think shrapnel from an energetic nuclear explosion would slice up the asteroid at the high speeds the small sharp masses would have.

 

[Nyogtha]

Shrapnel from . . . what?

Thermonuclear devices are not designed as frag weapons, the delivery system is absolutely vaporized.

The radiation released would still travel easily through space - should get anything in its path plenty warm. So thermal shock effects would be possible. It would all depend on the distance between the explosion and the object, as well as sizes of both (nuclear weapon yield vs. asteroid size).

If it's detonated while in contact with the asteroid then all sorts of shock effects would occur - the most reasonable use in this context. Make it designed to penetrate, then trigger.

Kinda like this but with a missile booster and nuclear explosive.

https://en.wikipedia.org/wiki/Massive_Ordnance_Penetrator

The irradiated chunks that burn up would still produce radioactive fallout but diluted to a really large degree vs. a surface tested or typically targeted airburst nuclear weapon.

What would happen to all the stuff we already have in orbit may pose an issue that would make diverting the course of the asteroid preferable. No satellite communications for fols to send selfies around the planet? The horror . . .

 

[Wolf359]

Originally Posted By: lubricatosaurus
Originally Posted By: Wolf359
You are talking about odds that are several orders of magnitude apart. Odds of a good asteroid hitting the earth is about one in a million years. No one has actually been hit by one in the last 1000 years.

You are more likely to win powerball, get killed because you're not wearing a seatbelt, get cancer, have a hearth attack etc than being killed by an asteroid.


Wrong again you are. You must not have ever heard of Tunguska 1908 explosion: "The Last Massive Exploding Meteor Hit Earth in 1908, Leveling 800 Square Miles of Forest .. In 1908, a meteor exploding in mid-air released the energy equivalent to "185 Hiroshima bombs"".

And as long ago as 2013 (back when dinosaurs roamed the earth???): "Early this morning in Russia, when a meteor broke up a few dozen kilometers above ground, its supersonic flight and mid-air death generated shock waves that rattled houses, broke windows, and sent dozens to the hospital. The meteor’s break-up released energy equivalent to a few hundred thousand tons of TNT.."

And another whopper from the age of the dinosaurs

all the way back 80k years ago:

You need to read what I actually wrote. The 1908 explosion didn't actually kill anyone. It happened in a very remote region. Again, number of people killed in the last 1000 years is ZERO.

Large amounts of energy released and actually number of people killed are two different things. It's not like we're lucky that the one over Russia didn't hit the ground, the size, and speed of it pretty much guarantees that it explodes in the air. If it was larger, it might have hit the earth intact. We're hit all the time by them, it's just that they usually occur over water so you don't have good video of them. And so far, they haven't actually killed anyone yet. Again, it's all about the odds.

I just remember attending a seminar about this and they went over the math of why we don't actually do more. The cost/benefit analysis showed that the ROI just wasn't there. We're probably better off trying to make people wear seat belts which would save real lives than spending the money to guard against a very remote possibility.

 

[bruno]

No one knows if any were killed in the Siberian hit so claiming zero is foolish .

 

[Shannow]

Originally Posted By: bruno
No one knows if any were killed in the Siberian hit so claiming zero is foolish .


Too true...and people win powerball every week as well.