Why SpaceX ’s Historic Mission Needs to Wait Until Saturday for a Second Attempt

When you’ve got a 230-ft. tall rocket filled with 76,000 gallons of explosive fuel sitting on the launch pad, the President in the viewing stands and millions worldwide waiting to watch the great machine fly, you’d figure you wouldn’t schedule the event for a spring afternoon in Florida, when bad weather stands to wreck the whole party. Those are exactly the conditions in which the SpaceX Falcon 9 rocket carrying astronauts Bob Behnken and Doug Hurley tried—and failed—to get off the launch pad on May 27, for the historic first crewed launch from American soil since 2011. The scrubbed flight left a lot of people asking, Why don’t NASA and SpaceX just pick a day and time to launch when the forecast is clear? The answer: It’s not up to them. It’s up to physics. If you were trying to launch any old spacecraft into any old orbit you could, indeed, pick pretty much any old time to fly. But things are almost never as simple as that, especially when you’re trying to rendezvous with another object already in Earth orbit — in this case, the International Space Station (ISS). Pulling off so delicate a pas de deux typically requires precise timing, which means launching in a fixed time frame on a fixed day within what’s known as a “launch window.” The most conspicuous orbiting object with which astronauts have attempted to rendezvous is the moon. Back in the days of the Apollo program, the trick was not to aim...
Source: TIME: Science - Category: Science Authors: Tags: Uncategorized Explainer Source Type: news