Julie Payette is still waiting to blast-off. The Endeavour space shuttle, which is supposed to take the Canadian astronaut to the International Space Station, is stuck on the ground for the second time in less than a week, thanks to a hydrogen gas leak. The problem is with ground equipment, not Endeavour itself, but still poses too much of a risk for NASA to allow a launch until the leak is fixed. The launch has been pushed back until July, when the shuttle will carry hundreds of pounds of food and the last segment of a Japanese designed laboratory to the International Space Station. The mission will be historic once it is off the ground—Payette will join Robert Firsk, a Canadian astronaut already in orbit, marking the first time two Canadians have ever been in space together. There will also be a total of 13 people at the space station, the most ever in orbit at once. In the meantime, Payette will be hitting the simulators to keep up her skills while she waits for lift-off.