Path-constrained rendezvous

In <a href="/facts/Spaceflight/zPrnATzo">spaceflight</a>, a path-constrained rendezvous is the process of moving an <a href="/facts/Orbit/nD2TPySG">orbiting</a> object from its current position to a desired position and velocity, in such a way that no obstacles are contacted along the way. It is a more constrained instance of the general problem of <a href="/facts/Space_rendezvous/8KlcQyyf">orbital rendezvous</a>.
When no obstacles need consideration, the problem of rendezvous is straightforward, and many efficient algorithms are available to plan the necessary <a href="/facts/Orbital_maneuver/HAlEFRSJ">maneuvers</a>. Depending on the desired time taken to accomplish the rendezvous, there are an infinite number of possible rendezvous paths.
The presence of obstacles posing a collision risk complicates the problem. The shortest-time or lowest-energy rendezvous might be made infeasible by obstacles, so a path requiring more time or more energy would have to be employed. For instance, if the purpose is to rescue an <a href="/facts/Astronaut/HB1bd6Lz">astronaut</a> in distress on the far side of a large <a href="/facts/Space_station/2HtaLbDH">space station</a>, speed is important. One may have to find quickly the rescue path requiring minimal time to execute, yet avoiding contact with the space station structure.
A natural object of study is the problem of maneuvering in the vicinity of a large orbiting <a href="/facts/Sphere/jywYLNM2">sphere</a>, since a collision with a more complex structure can be avoided by selecting rendezvous paths that avoid contact with a virtual sphere enclosing the structure. Early research considered the problem of departure and arrival points lying on the surface of an orbiting sphere. This led to a pair of necessary conditions called the tangential departure and tangential arrival conditions.

Path-constrained rendezvous open-in-new

Path-constrained rendezvous