This illustration shows many of the challenges using propulsive deorbiting:

enter image description here


  1. The trust line of the tug is aimed nowhere near the center of mass of the debris. The majority of thrust will produce angular momentum, not retrograde thrust.

  2. The trust direction has a radial component , which is a waste for deorbiting. Useful thrust is retrograde. Out-of-plane thrust is a complete waste. Radial thrust is inefficient.

  3. If this is a single-use tug, it will re-enter with the debris, an inefficient use of its launch costs.

  4. If this is a multi-use tug, it will need to prograde burn to climb back up to service altitude.

  5. Single-point grapple makes for unreliable thrust alignment during burn.

If propulsive junk deorbiting is to be worthwhile, it must make economical use of resources. Propulsion must be retrograde and through the center of mass. Multi-use “motherships” for rendezvous must not be put on a re-entry orbit by the retrograde burn.

Are there any propulsive deorbit proposals which answer these challenges?

  • 1
    $\begingroup$ The description of that image is an "artist’s concept", not a technical drawing. I'm not sure how productive analyzing it for efficiency will be. $\endgroup$ Commented Nov 4, 2022 at 8:02
  • $\begingroup$ How did you conclude the presence of radial thrust (point #2) from the figure ? $\endgroup$
    – AJN
    Commented Nov 4, 2022 at 13:02
  • $\begingroup$ Well you could use the spacecraft itself, as Joshua's comment in this question mentions: space.stackexchange.com/questions/60865/… or this proposal: aerospace.org/article/… and then if you allow non-propulsive method you could use a sail... newatlas.com/space/… $\endgroup$ Commented Nov 5, 2022 at 20:01
  • $\begingroup$ Oh, I've found another one; the tethered space tug - sciencedirect.com/science/article/pii/S1000936120305768 $\endgroup$ Commented Nov 5, 2022 at 20:03
  • $\begingroup$ @DaveGremlin ... nice links. Non-propulsive deorbiting with tethers and drag sails have great promise. Propulsive deorbiting of uncooperative debris has lots of challenges. The OP is seeking existing proposals which address fundamental design requirements. $\endgroup$
    – Woody
    Commented Nov 6, 2022 at 5:02


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