Author Topic: New paper on low delta-v asteroid capture  (Read 5435 times)

Offline Nilof

  • Full Member
  • ****
  • Posts: 913
  • Liked: 371
  • Likes Given: 540
New paper on low delta-v asteroid capture
« on: 02/20/2015 04:00 PM »
So far most asteroid capture studies have started from the assumption that to be captured, an asteroid has to have a negative C3 with respect to Earth. This paper doesn't, and considers capturing asteroids into orbits that have positive C3 but are still somehow stuck close to Earth(deviation from a one year period are self-correcting) so that they remain in close proximity:

http://arxiv.org/pdf/1501.03193v1.pdf

Maybe something like this could be used to capture bigger/faster asteroids?
« Last Edit: 02/21/2015 09:52 PM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline Hop_David

  • Full Member
  • ****
  • Posts: 1633
  • Ajo, Arizona
    • Hop's Gallery
  • Liked: 112
  • Likes Given: 40
Re: New paper on low delta-v asteroid capture
« Reply #1 on: 02/23/2015 05:36 PM »
So far most asteroid capture studies have started from the assumption that to be captured, an asteroid has to have a negative C3 with respect to Earth. This paper doesn't, and considers capturing asteroids into orbits that have positive C3 but are still somehow stuck close to Earth(deviation from a one year period are self-correcting) so that they remain in close proximity:

http://arxiv.org/pdf/1501.03193v1.pdf

Maybe something like this could be used to capture bigger/faster asteroids?

Tom Billings suggested this in the comments of Goff's pro-ARM article. Billings even noted that a temporarily captured moon had been discovered, it's more than just a theoretical possibility.

I like the idea but have concerns. SEPs have marvelous ISP but very weak thrust. They need a long time to execute a burn.

The earth moon neighborhood is more turbulent than regions in our neighborhood of the solar system. Most objects 1 A.U. from the sun are moving on the order of 1º/day about the sun. In contrast the moon moves about 12º/day about the earth. The DROs I looked at in another thread have a period of about a week. They move about 50º/day about the moon.

Would a temporarily captured asteroid stick around a given neighborhood long enough for an ion engine to do the needed burn?

Offline sdsds

  • Senior Member
  • *****
  • Posts: 5479
  • "With peace and hope for all mankind."
  • Seattle
  • Liked: 577
  • Likes Given: 677
Re: New paper on low delta-v asteroid capture
« Reply #2 on: 02/23/2015 09:17 PM »
I think in this context it is worth reading:
EASILY RETRIEVABLE OBJECTS AMONG THE NEO POPULATION
by D. García Yárnoz,* J. P. Sánchez,† and C. R. McInnes†
http://arxiv.org/pdf/1304.5082v2.pdf

which is reference 5 in the above-mentioned paper. It appears the propulsion needed to put an object into a Lyapunov
or Halo orbit around one of the co-linear Earth-Sun Lagrange points can be small, and the burns takes place at times/locations where they would be compatible with e.g. ion engine firings.

The key I think is that the capture burns both take place in the far reaches of the Earth's gravitational influence, and thus not anywhere near any deep gravity well.
-- sdsds --

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 27730
  • Minnesota
  • Liked: 7622
  • Likes Given: 5085
Re: New paper on low delta-v asteroid capture
« Reply #3 on: 02/28/2015 02:42 AM »
...
Would a temporarily captured asteroid stick around a given neighborhood long enough for an ion engine to do the needed burn?
Sure, just start it far enough ahead of time. This does, however, require a more sophisticated approach than is used for calculating when to do a chemical burn.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Tags: