Why are the “launch windows” so short for rendezvous missions?
Missions that rendezvous with the International Space Station, or other satellites like the Hubble Space Telescope can save fuel (and have more room for payload) if they wait until the ground track for the spacecraft they want to rendezvous with passes overhead. Then they launch into a slightly lower orbit, and chase down the target. You get the right time to launch twice a day, but one time will be more optimal than the other (due to climactic conditions at The Cape), and that’s when mission planners will schedule the flight for. You can also read A NASA provided explanation.
Missions that rendezvous with the International Space Station, or other satellites like the Hubble Space Telescope can save fuel (and have more room for payload) if they wait until the ground track for the spacecraft they want to rendezvous with passes overhead. Then they launch into a slightly lower orbit, and chase down the target. You get the right time to launch twice a day, but one time will be more optimal than the other (due to climactic conditions at The Cape), and that’s when mission planners will schedule the flight for.
