SpaceX's launch of a $340 million sun-observing spacecraft that was initially dreamed up by former US vice president Al Gore was postponed Sunday for at least 24 hours after a late problem.

The unmanned Deep Space Climate Observatory had been scheduled to blast off atop a SpaceX Falcon 9 rocket at 6:10 pm (2310 GMT) from Cape Canaveral, Florida but a range-tracking issue scuttled it with about two-and-a-half minutes left in the countdown.

DSCOVR's goal is to help space weather forecasters by collecting data on solar wind and geomagnetic storms that can cause damage to electrical systems on Earth.

"Air Force tracking radar went down. Launch postponed to same time tomorrow," tweeted Elon Musk, the billionaire SpaceX founder.

He added: "Prob good though. Will give us time to replace 1st stage video transmitter (not needed for launch, but nice to have)."

SpaceX was expected to try again at 6:07 pm on Monday.

After the launch, SpaceX will make another attempt to guide the first stage of its Falcon 9 rocket back to a controlled landing on an ocean platform, as part of the California-based company's goal of making rockets one day as reusable as airplanes.

In January, the rocket attempted a controlled maneuver to land on a powered-barge in the Atlantic, but collided with it instead and broke into pieces.