Challenge Hyperbolic Rendezvous

[flytandem]

Here's an interesting challenge. Not hugely fancy or difficult but does present a bit of a change from the usual get into orbit and rendezvous with the ISS type of scenario.

A DG is a few hours away from a hyperbolic flyby of the Earth. It is almost completely out of fuel. A rescue DG is sitting on the Earth. You should launch the rescue ship and dock with the flyby DG and apply thrust to get it back to a landing at the Earth. Also land the rescue ship. Can't waste a lot of time because the flyby DG is on a course to hit the moon if you don't get to it on time.

BEGIN_DESC
Launch the rescue ship and dock with the flyby DG and apply thrust to get it back to a landing at the Earth.
END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 55761.5876057043
END_ENVIRONMENT

BEGIN_FOCUS
  Ship 3
END_FOCUS

BEGIN_CAMERA
  TARGET 3
  MODE Cockpit
  FOV 60.00
END_CAMERA

BEGIN_MFD Left
END_MFD

BEGIN_MFD Right
END_MFD

BEGIN_PANEL
END_PANEL

BEGIN_SHIPS
3:DeltaGlider
  STATUS Landed Earth
  POS -82.4000000 22.9994600
  HEADING 151.05
  RCSMODE 0
  AFCMODE 7
  PRPLEVEL 0:1.000000 1:1.000000
  NAVFREQ 0 524 84 114
  XPDR 6
  GEAR 1 1.0000
  TRIM 1.000000
  AAP 0:0 0:0 0:0
END
flyby:Deltaglider
  STATUS Orbiting Earth
  RPOS 1540839.42 14741842.39 128371141.28
  RVEL -659.183 -580.601 -4606.481
  AROT 0.00 -0.00 0.00
  AFCMODE 7
  PRPLEVEL 0:0.000000 1:0.0007
  NAVFREQ 0 0 0 0
  XPDR 0
  AAP 0:0 0:0 0:0
END
END_SHIPS

BEGIN_VistaBoost
END

 

[dgatsoulis]

Unfortunately, i haven't had the time to try this one yet, but from what i saw in the scenario, the landed DG has a full tank of fuel.
So, unless the flyby DG is coming in from beyond Mars, there should be enough ΔV in the rescue (3) DG, to be able to grab it and bring it back. (I think).

EDIT: Just tried it. (The easy way).

Exactly as flytandem said. "Not hugely fancy or difficult but does present a bit of a change from the usual get into orbit and rendezvous with the ISS type of scenario."

This was a nice and refreshing challenge.
Not too difficult, with lots of spare ΔV to complete it.
Good for "intermediate" and also "advanced" Orbinauts.

The reason that i sensed that this was also a challenge for "advanced" Orbinauts, was this:
"Can't waste a lot of time because the flyby DG is on a course to hit the moon if you don't get to it on time."
:hmm: Hit the moon?
Then how about catching the incoming ship, a few minutes before it gets at Earth periapsis and then setting up a free-return trajectory?

Surely an option worth exploring, if you want to minimize ΔV.

Many thanks to Rob for this challenge. I'll try and come up with a LUA script for it.

For those of you that will try it (easy or difficult way).

Have fun, happy orbiting!

 

[gder]

Just flew this and found it quite fun. It took me a couple tries to get the technique down, IMFD's velocity match tool is super handy.

I did it a couple different ways, I'm not sure which one is the best. It would depend on the scenario, the first is incredibly dv expensive and left me with almost no fuel. The second left me with more fuel but involves roughly a 7 day flight around the moon.

1) Launch into orbit, align planes, then expand the orbit so that I would meet the ship at periapsis. I had to eyeball this using the orbital display since the sync orbit MFD doesn't seem to work if your target is hyperbolic.

2) Use IMFD Target Intercept and program the TIn for roughly 3k before periapsis. After docking use IMFD Target Intercept and the map program to plan an offset trip back to the moon. I think my TIn to the moon was something like 280k or 300k seconds. I couldn't quite tweak the orbit right to get the flyby craft back into Earth atmosphere so I ended up escorting it around the moon and tweaking the orbit on the way back to Earth.

Landing the flyby ship was difficult as it's out of main as well as RCS fuel. This makes holding attitude fairly difficult until you start to get down into the atmosphere. If I was in an XR2 I'm pretty sure I would have burned up, especially on the second rescue where you're inbound at a much higher velocity.