Boeing Starliner Launch Delayed by Propulsion Problem

United Launch Alliance, the joint venture between Boeing and

Lockheed Martin Corp.

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that handles the rockets that would ferry the Starliner into space, will begin removing propellant from the rocket it planned to use for the flight.

NASA is testing the capsule ahead of its planned first flight with astronauts on board later this year. The agency said the next available window to launch the Starliner from Cape Canaveral Space Force Station in Florida is Aug. 4 at 12:57 p.m. ET.

Boeing said its engineers conducting prelaunch checks of the Starliner initially detected the issue after electrical storms on Monday near the launch site.

“We’re disappointed with today’s outcome and the need to reschedule our Starliner launch,” said

John Vollmer,

a Boeing vice president overseeing the program.

“Human spaceflight is a complex, precise and unforgiving endeavor, and Boeing and NASA teams will take the time they need to ensure the safety and integrity of the spacecraft and the achievement of our mission objectives,” he said.

A botched effort in late 2019 dented the record of a company that has been at the forefront of U.S. space exploration, including the Apollo missions to the moon. The Starliner is the latest of an array of new rockets, capsules and other vehicles aimed at furthering U.S. ambitions in a new space race to the moon, Mars and beyond.

The Starliner would give the U.S. more options to reach low earth orbit and the space station. U.S. astronauts had to hitch rides on Russian Soyuz spacecraft to get there following the retirement of the Space Shuttle in 2011. NASA opted to outsource a replacement through its Commercial Crew Program and picked Boeing and Space Exploration Technologies Corp., the formal name for

Elon Musk’s

SpaceX, to provide space taxi services.

The CST-100 Starliner is slated to deliver more than 400 pounds of NASA cargo and crew supplies, and bring back material including oxygen tanks. A mannequin named Rosie the Rocketeer is expected to be on board, equipped with sensors to capture data ahead of a crewed mission.

What went wrong with the last mission?

The first uncrewed Starliner test flight in December 2019 failed to reach the space station. A software error left the spacecraft in the wrong orbit, ground controllers had difficulty communicating with the vehicle and another computer problem affected its thrusters. The spacecraft returned safely to Earth after two days, though NASA said it could have made it to the space station if astronauts were on board.

Boeing and NASA have completed multiple reviews and tests ahead of the latest launch. Working under a fixed-price contract with NASA, Boeing took a $410 million charge to pay for the second test mission, and will ferry the cargo to and from the space station for free.

When will the Starliner carry astronauts?

A second Starliner capsule is scheduled to carry astronauts to the space station as early as November, if the testing goes as planned. The reusable spacecraft is designed to fly 10 times and can be refurbished in six months.

How does it compare to the SpaceX Crew Dragon capsule?

The Starliner can carry seven astronauts or a mix of crew and cargo. It is launched on the same Atlas V series rockets developed by the joint venture between Boeing and

Lockheed Martin Corp.

that are used for military satellites. The spacecraft is autonomous, though there are backup controls that allow it to be piloted. It is designed for land-based returns, descending under parachutes, with air bags to cushion the landing.

The SpaceX Crew Dragon has carried cargo to the space station since 2012 and took its first astronauts to the space station in May 2020. The fully autonomous Dragon is launched on the SpaceX Falcon 9 rocket and has seven seats, though like the Starliner only four are used for NASA missions. It is designed to land under parachutes in the ocean.

What else does Boeing do in space?

Boeing is one of the world’s largest space companies, with analysts estimating annual revenue of around $6 billion from the business last year. It has already helped refurbish the International Space Station this year and builds a range of satellites.

It is a pivotal year for Boeing’s space ambitions. Beyond the Starliner, it makes the main body of the Space Launch System, an enormous deep space rocket that will carry astronauts. After years of delay, a ground test in March paved the way for a potential launch by the end of the year as part of NASA’s Artemis moon exploration program.

Write to Micah Maidenberg at micah.maidenberg@wsj.com and Doug Cameron at doug.cameron@wsj.com