[ExI] new job

[BillK]

On Wed, 18 Dec 2024 at 20:54, Adrian Tymes via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

> What would it take to nudge Apophis from "might impact Earth later" into a
> stable orbit around the Earth, or perhaps the Moon (and thus around the
> Earth)?
> _______________________________________________
>



Perplexity AI thinks it is an impossible task.
BillK

Perplexity AI -
To slow Apophis enough to enter Earth's orbit would be an extremely
challenging and potentially dangerous endeavor. Apophis is a large asteroid
with an estimated mass of 6.1×10^10 kg[1]. Altering its trajectory
significantly would require an enormous amount of energy and precise
calculations. Here's an analysis of what would be theoretically required:

## Orbital Mechanics

Apophis currently has an elliptical orbit around the Sun with a period of
about 0.89 years[1][2]. To capture it into Earth orbit, we would need to:

1. Reduce its velocity relative to Earth
2. Change its trajectory to intersect with Earth's gravitational sphere of
influence
3. Apply additional deceleration to prevent it from escaping Earth's gravity

## Energy Requirements

The change in velocity (Δv) required would be substantial:

1. Apophis has an average orbital speed of 30.73 km/s[1]
2. Earth's orbital velocity is approximately 29.78 km/s
3. The Δv needed would be on the order of several km/s, depending on the
exact capture scenario

Given Apophis's large mass, the energy required for such a maneuver would
be enormous, far exceeding our current technological capabilities.

## Potential Methods

While not feasible with current technology, theoretical approaches might
include:

**Enhanced Kinetic Impactor (EKI)**
An EKI could potentially be used to slow Apophis, but it would require:
- Collecting hundreds of tons of rock from a Near-Earth Asteroid
- Multiple impacts to achieve the necessary Δv[5]

**Gravity Tractor**
A massive spacecraft could use gravitational attraction over an extended
period to alter Apophis's trajectory[3]. However, this method is too slow
and weak for the drastic changes required for orbital capture.

**Laser Ablation**
High-powered lasers could vaporize surface material, creating thrust to
slow the asteroid[4]. This would require an enormous space-based laser
array, far beyond our current capabilities.

**Ion Beam Deflection**
A powerful ion engine could theoretically provide continuous thrust[3], but
the scale required for Apophis would be impractical with current technology.

## Risks and Challenges

Attempting to capture Apophis into Earth orbit would be extremely risky:

1. Any miscalculation could potentially direct Apophis towards Earth,
causing catastrophic damage.
2. The close proximity required for such maneuvers would put Earth at risk.
3. Even if captured, stabilizing Apophis in Earth orbit would be an ongoing
challenge.

## Conclusion

 asteroids away from Earth rather than capturing theWhile theoretically
possible, slowing Apophis enough to enter Earth orbit is far beyond our
current technological capabilities and would be extremely dangerous. The
energy requirements are enormous, and the risks far outweigh any potential
benefits. Current planetary defense strategies focus on deflecting
potentially hazardousm[3][4].

Citations:
[1] https://en.wikipedia.org/wiki/99942_Apophis
[2] https://science.nasa.gov/solar-system/asteroids/apophis/
[3]
https://newspaceeconomy.ca/2024/06/02/defending-earth-strategies-for-deflecting-hazardous-asteroids/
[4]
https://www.planetary.org/articles/asteroid-deflection-techniques-to-save-the-earth
[5] https://pmc.ncbi.nlm.nih.gov/articles/PMC7244770/
[6] https://nss.org/technologies-for-asteroid-capture-into-earth-orbit-2/
[7] https://www.spacereference.org/asteroid/99942-apophis-2004-mn4
[8]
https://www.aanda.org/articles/aa/full_html/2014/03/aa22364-13/aa22364-13.html
[9]
https://space.stackexchange.com/questions/59212/how-could-99942-apophis-in-2029-be-captured-and-brought-into-a-low-earth-orbit
[10] https://www.esa.int/Space_Safety/Planetary_Defence/Apophis
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