How do spacecraft perform orbital rendezvous maneuvers?

Orbital rendezvous requires precise control of a chaser spacecraft to match the orbit and relative motion of a target. As explained by Richard H. Battin, Massachusetts Institute of Technology, the fundamental task is not merely reaching the same altitude but arriving at the same position and velocity vector so the two vehicles move together. Howard D. Curtis, Brigham Young University, emphasizes that timing and energy budgeting determine feasible transfer strategies and mission risk.

Phasing and transfer orbits

Most rendezvous sequences begin with phasing maneuvers that adjust the chaser’s orbital period so it arrives at the intercept point when the target is there. Engineers commonly use impulsive two-impulse transfers such as Hohmann-like elliptical burns when orbits are coplanar and the phase angle is favorable, because these minimize propellant for many cases. When plane changes are required, mission planners weigh the high delta-v cost of inclination adjustments against alternative strategies like launching into a different plane or performing plane change at higher altitude to reduce fuel. Curtis provides practical methods for computing these maneuvers and the resulting delta-v requirements, which directly affect payload mass and mission economics.

Guidance, navigation, and control systems implement the planned burns and maintain safe separation until final approach. Relative motion near the target is governed by linearized dynamics around a circular reference orbit, and guidance algorithms translate those dynamics into sequenced burns and velocity corrections. Onboard sensors combine inertial measurement, global navigation satellite data, radar, lidar, and optical cameras to estimate range, bearing, and closing velocity. Redundant systems and human oversight reduce the risk of misestimation that could produce collision or forced abort, a concern highlighted in operational studies at NASA Johnson Space Center.

Final approach and docking

Final approach profiles, sometimes described as V-bar or R-bar approaches depending on whether the chaser approaches along the target’s velocity vector or radial direction, balance propulsion efficiency with safety. Slow, controlled closing rates and continuous relative navigation allow automated docking mechanisms or crewed manual control to execute capture. Successful docking enables crew transfer, resupply, on-orbit servicing, and close-proximity inspection, all of which extend mission lifetimes and operational flexibility for space infrastructure.

The consequences of rendezvous operations extend beyond mission success. A failed or mismanaged approach can create debris that threatens other spacecraft and complicates orbital traffic management, amplifying environmental risk in crowded low Earth orbit. Culturally and politically, routine rendezvous capability underpins international cooperation exemplified by joint ISS logistics and crew exchanges coordinated by NASA Johnson Space Center and partner agencies, while also serving strategic national interests in satellite servicing and on-orbit assembly. Mastery of rendezvous techniques therefore shapes not only technical outcomes but the environmental stewardship and geopolitical dynamics of near-Earth space.