B Oberth Effect Near Sag A*

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The discussion centers on the feasibility of achieving a final velocity of 0.95c for a spacecraft using the Oberth effect near Sagittarius A*. It explores the dynamics of a Falcon 9-sized craft with a delta-v of 0.33c, already consuming 0.1c, leaving 0.23c for a burn near the black hole. Calculations suggest that while the Oberth effect provides a velocity boost, it is insufficient to reach the desired speed, with final velocities calculated around 0.6059c at best. The conversation highlights the complexities of relativistic velocities and the differences between hyperbolic and parabolic flybys, noting that deeper gravity wells can enhance the effect. Ultimately, the consensus indicates that achieving 0.95c under the given parameters is not possible.
  • #31
PeterDonis said:
Heuristically, at periapsis it's going to slightly squeeze the ship, since the ship will be oriented tangentially.
"Slightly" depends on ship size and black hole size, so if @Devin-M is considering a flight path via other BHs then that might affect his thinking. That's the only point I was making.
 
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  • #32
Ibix said:
E is the kinetic energy at infinity
kinetic energy per Kg?
 
  • #33
Devin-M said:
kinetic energy per Kg?
My apologies - it's the total energy per kilogram.

I'll edit my post above.
 
  • #34
Sorry it’s taken me so long. I’m planning to run the numbers with a 5 solar mass black hole and a 1 solar mass black hole - in a conversation I had with Grok, it told me that the 5 solar mass BH could give 0.95c and the solar mass black hole could give 0.99c at a large distance in this scenario (with a .1c approach speed and 0.23c burn). Does that seem reasonable? I’m very curious if when I run the numbers that will indeed be the case.
 
  • #35
Devin-M said:
in a conversation I had with Grok, it told me that the 5 solar mass BH could give 0.95c and the solar mass black hole could give 0.99c at a large distance in this scenario (with a .1c approach speed and 0.23c burn). Does that seem reasonable?
Not even close, based on calculations posted earlier in this thread.
 
  • #36
Devin-M said:
I’m planning to run the numbers with a 5 solar mass black hole and a 1 solar mass black hole
Note that in the calculations posted earlier in the thread, the mass of the central object (whether it's a black hole or the planet Jupiter or anything in between) doesn't matter in itself. All that matters is the ratio ##M / r## at periapsis.
 

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