On Tuesday morning, SpaceX attempted an altitude test of its next generation rocket for the fourth time and it exploded for the fourth time.

Through a series of test flights since December, SpaceX has successfully launched prototypes of Starship that will one day take people to Mars and demonstrated a controlled belly flop back to the ground after reaching an altitude of several miles. But each time the missile encountered problems during or after landing, resulting in spectacular explosions.

This time something went wrong earlier when the engines re-ignited at the beginning of the landing process. The SpaceX video then froze at 5:49 minutes after launch.

Reporting from NASASpaceflight, a space enthusiast website, showed shards of metal raining around the launch site, including debris hitting one of the cameras.

“Looks like we’ve had another exciting test,” said John Insprucker, a SpaceX engineer who shared the company’s webcast.

The start was shrouded in early morning fog and only seen by cameras on Starship.

Elon Musk, the founder and CEO of SpaceX, said on Twitter that there appeared to be a problem with one of the engines during the ascent and that it wasn’t working properly when it reignited on landing. But, he added, it shouldn’t have been used.

SpaceX takes a fail-safe and fastest possible approach. The tests are used to identify design flaws and make adjustments on subsequent flights.

The previous test on March 3rd produced an achievement that none of the previous flights had managed: the spaceship landed back at the launch site, but leaned against the landing pad.

Shortly after SpaceX commentators declared this test successful and completed the live webcast, a camera maintained by NASASpaceflight captured the rocket exploding on the ground.

Mr Musk later said on Twitter that the engine thrust was less than needed to slow the missile, which hit the ground at a speed of 10 meters per second, or 22 miles per hour. The force of impact squeezed the legs and part of the bottom of the missile together.

Mr. Musk’s company has become successful in the start-up business and is now one of the most valuable private companies in the world. The Falcon 9 missiles have become a dominant workhorse for sending satellites into orbit. It routinely carries cargo to the International Space Station and has lifted NASA astronauts there twice in 2020. Further trips are planned for this year.

However, many are skeptical of Mr. Musk’s claim that the company is only a few years away from sending a spaceship to Mars, saying he has repeatedly set schedules for SpaceX that have proven far too optimistic.

When he released an update on Starship’s development in 2019, he said that an altitude test would take place within months and that orbital flights could take place in early 2020.

Instead, several catastrophic failures occurred due to faulty welding. When the fuel tanks stopped bursting, two of the prototypes made short successful flights last year. These earlier Starship prototypes resembled spray paint cans with the labels removed and soared nearly 500 feet on a single rocket engine before being returned to the test site in Texas.

With the recent failure, Starship is far from ready for a trip to orbit. But SpaceX already has future tests in mind that will lift subsequent Starship prototypes to much greater heights. Earlier this month, Mr. Musk shared a picture of a prototype of the large booster stage needed for a trip into space. It’s over 200 feet tall.

Although that prototype won’t fly by itself, Musk said the company’s goal is to have a second model out on the market by July.

Tuesday’s Texas test wasn’t the only SpaceX activity that caught attention towards the end of the week. Late on Thursday, people in the Pacific Northwest discovered mysterious bright lights in the night sky. The light show did not consist of airplanes or meteors, but of the debris from a SpaceX rocket.

Jonathan McDowell, an astronomer at Harvard University’s Center for Astrophysics, wrote on Twitter that the grazing objects were part of a Falcon 9 rocket that was launched in early March. The debris returned to the atmosphere after 22 days in orbit, he said.

Mike Ives contributed to the coverage.