A SpaceX Falcon Heavy rocket lifts off from historic launch pad 39-A at the Kennedy Space Center in Cape Canaveral, Florida, U.S., February 6, 2018.

The second flight of the most powerful rocket in operation is about three weeks away, people familiar with the plans told CNBC on Friday.

SpaceX's massive Falcon Heavy rocket is scheduled for its next launch no earlier than April 7 at 6:36 pm ET (22:36 UTC), the people said, who spoke on condition of anonymity.

The mission, called Arabsat 6A, will launch a large communications satellite for Saudi Arabian corporation Arabsat. Built by Lockheed Martin, the satellite is described by Lockheed vice president Lisa Callahan as one of "the most advanced commercial communications satellites we've ever built."

Arabsat 6A was previously targeting as early as the third quarter of last year but has slipped several months, one of the people noted. SpaceX has not conducted a test fire of the rocket on its launchpad at NASA's Kennedy Space Center, which is typically done one or two weeks before.

This will be the first flight of Falcon Heavy since its nearly flawless maiden launch in February 2018. With a price tag between $90 million and $150 million per launch, Falcon Heavy has racked up a valuable manifest of future launches, even though it's only flown once. Additionally, the U.S. Air Force certified Falcon Heavy for national security launches last year, as well as gave SpaceX a $130 million contract to launch an Air Force Space Command satellite.

SpaceX built Falcon Heavy out of three of the company's Falcon 9 rockets — a system that has now completed dozens of successful launches over the last few years. The three cores stand side by side to create a 27-engine colossus. SpaceX founder and CEO Elon Musk has said the central core needed "to be buffed up a lot" but the Falcon 9 cores on each side "use most of the same airframe."

SpaceX did not immediately respond to CNBC's request for comment.