This story was updated March 11

WASHINGTON — Representatives from the U.S. launch industry’s two biggest rivals — SpaceX President Gwynne Shotwell and United Launch Alliance Chief Executive Tory Bruno — will face off at a U.S. House subcommittee hearing March 17.

The two executives will testify before the House Armed Services strategic forces subcommittee as part of an industry panel on “Assured Access to Space.” The subcommittee originally invited SpaceX CEO Elon Musk to the hearing, but a witness list released March 11 shows Shotwell will represent the company.

The two companies are battling for the U.S. government’s launch business but also for the hearts and minds of U.S. lawmakers, many of whom have complained about the current high cost of launching national security missions.

This would not be the first joint appearance before Congress by the top executives of SpaceX and ULA. Last March, Musk and Michael Gass, Bruno’s predecessor, squared off before the Senate Appropriations defense subcommittee, where they were offered the opportunity to submit written questions to one another.

Musk’s questions zeroed in on the roughly $1 billion ULA receives annually in so-called Evolved Expendable Launch Vehicle Launch Capability funding, which covers costs that are not necessarily tied to individual missions. He challenged Gass to fold those costs into a single overarching EELV contract whose value is divided on a mission-by-mission basis.

Gass, for his part, forced Musk to acknowledge that SpaceX currently is capable of handling only 60 percent of the Defense Department’s payloads and that government requirements would tend to drive SpaceX launch prices higher than the company’s advertised rates.

Bruno is a former Lockheed Martin vice president — ULA is a Boeing-Lockheed Martin joint venture — who took over ULA in August. He has proved more outspoken than Gass, using social media, mainly Twitter, to advocate for his company and take jabs at Musk.

Following the industry panel will be a second session in which witnesses include: Katrina McFarland, assistant secretary of defense for acquisition; Bill LaPlante, assistant secretary of the Air Force for acquisition; Gen. John Hyten, commander of Air Force Space Command; and Mitch Mitchell, vice president at the Aerospace Corp., which provides engineering advice on U.S. national security space programs.