XM Satellite Radio has learned a lesson about hyping something too early. Last Friday at the Consumer Electronics Show in Las Vegas, the digital radio service promoted Monday’s launch of the first of two satellites the company will use as the first serious step toward hitting the airwaves this summer. But plans were quickly scrapped Monday — about 30 seconds before the planned liftoff. Boeing-led Sea Launch Co. of Long Beach did not explain the cancellation. Weather conditions were favorable at the Odyssey launch platform in the Pacific Ocean, 1,300 miles south of Hawaii. There’s no word on when the launch will be attempted again. Washington, D.C.-based XM Satellite Radio plans to offer 100 channels of subscription digital programming broadcast directly to U.S. customers. Service will initially be available to people who purchase new car satellite radios and pay a $10 monthly service fee.