Advanced Grabbing Unit

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Advanced Grabbing Unit
Part image
Docking port by
Kerbal Motion LLC

Radial size Small
Cost (total) 450.00 Funds
Mass (total) 0.08 t
Drag 0.2-0.3
Max. Temp. 2000 K
Volume  ?
Impact Tolerance 50 m/s
Research Actuators.png Actuators
Unlock cost 5 200 Funds
Since version 0.23.5
Part configuration part.cfg

The Advanced Grabbing Unit (AGU), or The Klaw (or 'claw'), is a medium-sized docking device which can couple to any surface without the requirement of another docking device on the target to mate with. This is a virtual necessity for redirecting asteroids or comets, though the AGU can be used to grab onto much more than just asteroids. In fact, it can grab just about anything, even Kerbals.

Product description

Kerbal Motion engineers have long struggled with the problem of how to extract dropped tools from complicated machinery. After observing an intern cleaning out his shoes by turning them upside and shaking them inside the lab, our team was hit with a stroke of inspiration! Why not turn the rocket parts upside down and shake them? The grabbing arm perfectly filled this niche, and is quite capable of lifting heavy machinery. It has since found other uses, besides delicate tool extraction operations. AKA "The Klaw!"

Kerbal Motion LLC


Advanced Grabbing Unit opened

The AGU is the primary means of capturing and redirecting asteroids, and of destroying a planet and vessels within 200m of the klaw under certain circumstances [1]. It's also useful for craft-to-craft docking or for exchanging resources with craft or debris without a docking port. As with docking ports, resources (liquid fuel, electricity, etc.) can be exchanged with the target. And objects connected by claws are controlled together as a single entity. It's like a docking port, but without the complexity of aligning with a receiving port on the target. Kerbals grabbed by the AGU's claw will go limp in a ragdoll state and can be carried with the craft.

Operation is simple. Its state toggles between Armed or Disarmed. While disarmed, it behaves like any other part. Once armed, approach perpendicularly to the target surface at no more than a few m/s and the extended claw will automatically grab anything it collides with (or that collides with it), docking the target to the current vessel.[2] To undock from the target, right-click the AGU and choose Release.

Once the AGU is attached, its claw's pivot can be toggled. The pivot is locked whenever armed and not attached, but can then be unlocked by right-clicking the AGU and choosing Free Pivot. While freed, reaction wheels or RCS can be used to alter the craft's pitch and yaw (from the AGU's perspective) relative to the target, but not roll; the claw turns, not twists. This is vital when attached to asteroids, as thrust must be aimed directly at the center of mass to keep the asteroid under control while moving it. Note that controls may feel reversed; the opposite end of the craft from the claw will be moving. Note also that the range of motion the pivot provides is bounded by a circle, like the AGU itself, essentially drawing a conical area.

After aligning the craft, the Lock Pivot command can be used to fix the craft's orientation relative to the grabbed target. Note that even when locked, with sufficient lateral force the pivot can be bent, though once the force is removed it will bend back to its locked orientation. It is also possible with pre-assigned Action Groups to “Disarm” the AGU while attached without releasing it − a merely visual effect.

Special Usage Notes

  • When a target vessel is captured with a klaw, the combined vessel usually gets a new "Control from Here" point. That point is almost never pointing in the same direction as the previous control point; which means that all the navigational targeting will suddenly be "off". Make sure to reset your "Control from Here" point after every single klaw docking, or your ship will be thrusting in very surprising directions.

Non-active AGU bug

Bug screenshot: planet is missing

In versions prior to 1.1, it was possible to break the game by connecting to a klaw that is not on the active vessel. The celestial body being orbited would disappear as soon as the klaw connects (see image in sidebar). Doing the same maneuver in recent versions of the game works properly.

Grabbing a Kerbal

A Kerbal successfully grabbed with the AGU in orbit

With the Advanced Grabbing Unit it is, although tricky, possible to dock to a Kerbal. The Kerbal must be touched with the exact center of the extended claw in order to capture; touching the Kerbal to the claw arms has no effect. The AGU will not close around the Kerbal; rather, it will simply indicate that it has docked with something, and the Kerbal will be locked in place while still free to ragdoll. The easiest way to grab a Kerbal is to use the Kerbal's own jetpack to steer into the exact center of the claw. When docked successfully, your controls will change to the ship's controls, and the option to EVA with that Kerbal will not be available until the AGU is released. The same Kerbal-AGU system can safely withstand reentry with adequate deceleration to landing velocity.


  • It is possible the name "Klaw" is a reference to "Toy Story".
  • In previous versions it was necessary to disarm the klaw to reset it after each use. This no longer seems to be required.
  • There is a bug in version 1.1.3 that sometimes resets the "Control from Here" point when you switch focus to the craft, and sometimes when you activate the navball in map mode.


  • Initial release


  1. Danny2462's "The Glitch Device" can be used for fun, or creating Atlantis
  2. Unofficial fan-made video "How to Capture an Asteroid (Kerbal Space Program)" by YouTuber Harv of HOCgaming