SpaceX delays Polaris Dawn astronaut launch to Aug. 28 due to helium leak

A black and white rocket topped by a white space capsule stand on a launch pad under a darkening evening sky.

We'll have to wait at least another day to see SpaceX's historic Polaris Dawn astronaut mission lift off.

Polaris Dawn, which will conduct the first-ever private spacewalk, had been scheduled to launch early Tuesday morning (Aug. 27) from NASA's Kennedy Space Center in Florida. But a helium leak has forced a delay of at least 24 hours.