Enlarge / Firefly Aerospace's fourth Alpha rocket lifted off December 22 from Vandenberg Space Force Base, California. (credit: Firefly Aerospace/Trevor Mahlmann )

Welcome to Edition 6.25 of the Rocket Report! We hope all our readers had a peaceful holiday break. While many of us were enjoying time off work, launch companies like SpaceX kept up the pace until the final days of 2023. Last year saw a record level of global launch activity, with 223 orbital launch attempts and 212 rockets successfully reaching orbit. Nearly half of these missions were by SpaceX.

As always, we welcome reader submissions , and if you don't want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets, as well as a quick look ahead at the next three launches on the calendar.

Firefly's fourth launch puts payload in wrong orbit. The fourth flight of Firefly Aerospace's Alpha rocket on December 22 placed a small Lockheed Martin technology demonstration satellite into a lower-than-planned orbit after lifting off from Vandenberg Space Force Base, California. US military tracking data indicated the Alpha rocket released its payload into an elliptical orbit ranging between 215 and 523 kilometers in altitude, not the mission's intended circular target orbit. Firefly later confirmed the Alpha rocket's second stage, which was supposed to reignite about 50 minutes after liftoff, did not deliver Lockheed Martin's satellite into the proper orbit. This satellite, nicknamed Tantrum, was designed to test Lockheed Martin's new wideband Electronically Steerable Antenna technology to demonstrate faster on-orbit sensor calibration to deliver rapid capabilities to US military forces.

Enlarge / SpaceX's Falcon Heavy rocket lifted off Thursday night from NASA's Kennedy Space Center in Florida. (credit: SpaceX )

It seems like SpaceX did everything this year but launch 100 times.

On Thursday night, the launch company sent two more rockets into orbit from Florida. One was a Falcon Heavy, the world's most powerful rocket in commercial service, carrying the US military's X-37B spaceplane from a launch pad at NASA's Kennedy Space Center at 8:07 pm EST (01:07 UTC). Less than three hours later, at 11:01 pm EST (04:01 UTC), SpaceX's workhorse Falcon 9 launcher took off a few miles to the south with a payload of 23 Starlink Internet satellites.

The Falcon Heavy's two side boosters and the Falcon 9's first stage landed back on Earth for reuse.

A SpaceX Falcon Heavy rocket is seen outside the company's hangar at Kennedy Space Center, Florida. (credit: SpaceX)

SpaceX and the US Space Force thought they were ready to launch the military's mysterious X-37B spaceplane this week, but ground teams in Florida need to roll the Falcon Heavy rocket back into its hangar for servicing.

This is expected to push back the launch until at least late December, perhaps longer. SpaceX and Space Force officials have not divulged details about the problems causing the delay.

SpaceX called off a launch attempt Monday night at NASA's Kennedy Space Center in Florida to resolve a problem with a ground system. A senior Space Force official told Ars on Wednesday that additional issues will cause an additional delay in the launch.

Enlarge / SpaceX's Falcon Heavy rocket stands on Launch Complex 39A in Florida, hours before its scheduled liftoff with the military's X-37B spaceplane. (credit: Trevor Mahlmann/Ars Technica)

CAPE CANAVERAL, Florida—A SpaceX Falcon Heavy rocket is poised for launch as soon as Tuesday night from the Kennedy Space Center in Florida, and the US military's mysterious X-37B spaceplane is fastened atop the heavy-lifter for a ride into orbit.

Although the Space Force is keeping details about the military spaceplane's flight under wraps, we know it's heading into an unusual orbit, probably significantly higher than the X-37B's previous sojourns that stayed within a few hundred miles of Earth's surface.

SpaceX's launch team called off a launch attempt Monday night "due to a ground side issue" and reset for another launch opportunity as soon as Tuesday night at 8:14pm EST (01:14 UTC). When it lifts off, the Falcon Heavy will light 27 kerosene-fueled engines to power the rocket off its launch pad overlooking the Atlantic coastline.

Enlarge / The military's X-37B spaceplane landed last November to end the program's sixth mission. (credit: US Space Force/Staff Sgt. Adam Shanks )

The US military's reusable X-37B spaceplane will launch on the next flight of SpaceX's Falcon Heavy rocket, scheduled for December 7, officials announced on Wednesday.

This was unexpected because the spaceplane's six previous missions launched on medium-lift Atlas V or Falcon 9 rockets. This next mission, the seventh by an X-37B spaceplane, will fly on a heavy-lift launcher for the first time.

The payload for the next Falcon Heavy rocket was a secret before the military's announcement on Wednesday. The mission was known simply by the designation USSF-52, and it will take off from NASA's Kennedy Space Center in Florida.