Change the base with confidence

Canadarm2 has a Latching End Effector at each end. An end can attach to a power data grapple fixture on the station, while the other performs a task. The fixture supplies the connections needed for operation, including power and communication. The archive calls the flight hardware Canadarm-2; that spelling identifies the same station arm.

The arm’s ability to change its anchored end expands the set of working configurations. This does not make it a free-flying spacecraft or mean any nearby handrail is a suitable base. A connection must be designed for the required mechanical and electrical functions.

Consider an original, deliberately simplified model with three states: anchored at A, attached at A and B, and anchored at B. A verified second attachment provides continuity while the working base changes. This diagram teaches a dependency; it is not a flight procedure or a complete account of the arm’s control logic.

In the model, a camera image that looks aligned is different evidence from an attachment indication. If the intended transition requires a confirmed connection at B, an image alone does not satisfy that condition. A drawing of the final state cannot establish that the system has reached it.

Changing the base also changes the geometry of the next task. The same target may be approachable from one configuration and blocked from another. An unobstructed endpoint does not guarantee an unobstructed path for every joint and attached item.

Changing the working base

The Mobile Base System rides on the Mobile Transporter along the truss. CSA’s published description separates travel from work: the base and its attachments are powered down for relocation, then powered after latching at a worksite. That is different from Canadarm2 changing which of its ends is anchored.

In a toy schedule, allow 12 minutes to relocate a platform and 8 minutes for a separate readiness check. The next task cannot begin before 20 minutes if the stages must occur in sequence. These invented values illustrate dependency and elapsed time; they are not station operating durations.

A useful planning question is therefore not simply “Can the arm reach?” Ask which base is connected, which interfaces are available and which required checks have finished. Keeping these states explicit avoids confusing physical proximity with readiness.