A hold-down mechanism for a steerable spacecraft appendage, the appendage being coupled to a spacecraft structure with a positioning mechanism, is configured (1) to support, when in a hold-down mode, the appendage at a first position substantially fixed with respect to the spacecraft; (ii) release, upon receipt of a signal, the appendage, thereby enabling the positioning mechanism to steer the spacecraft appendage; and (iii) retract from the appendage without regard to whether the appendage remains substantially in the first position. The first position may result in the spacecraft appendage being aligned in a nominal operating location and orientation, so that the antenna positioning mechanism is not required to initially deploy or otherwise reorient the appendage.