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.
You can watch the launch using SpaceX’s live video feed on X, the social media platform, or if you prefer YouTube, third-party streams are available from Spaceflight Now and NASASpaceflight.
The exact altitude the X-37B will be flying through is unclear, but hobbyists and amateur sleuths who use open source information to reconstruct trajectories of top-secret military spacecraft suggest the Falcon Heavy will haul the winged vehicle into an orbit that could stretch tens of thousands of miles above the planet.
What’s more, the Falcon Heavy will apparently take a flight path toward the northeast from Florida’s Space Coast, then ultimately release the X-37B on a trajectory that will take it over Earth’s polar regions. This is a significant departure from the flight profile for the military spaceplane’s six previous missions, which all flew to space on smaller rockets than the Falcon Heavy.
In a statement, the Space Force said this flight of the X-37B is focused on “a wide range of test and experimentation objectives.” Flying in “new orbital regimes” is among the test objectives, military officials said.
“It seems to me like it might be a much higher orbit that it’s going to,” said Brian Weeden, director of program planning for the Secure World Foundation, which promotes sustainable and peaceful uses of outer space. “Otherwise, I don’t know why they would use a Falcon Heavy, which is a pretty big thing.”
Covering more ground
The X-37B spaceplane has attracted a lot of attention and speculation since its first mission in 2010. Across multiple administrations, Pentagon officials have consistently walked a narrow line between acknowledging the existence of the spaceplane, and divulging limited information about its general purpose, while treating some details with the utmost secrecy. The military does not talk about where in space it flies. With a few exceptions, defense officials haven’t publicly discussed specifics of what the X-37B carries into orbit.
The military has two Boeing-built X-37B spaceplanes, or Orbital Test Vehicles, in its inventory. They are reusable and designed to launch inside the payload fairing of a conventional rocket, spend multiple years in space with the use of solar power, and then return to Earth for a landing on a three-mile-long runway, either at Vandenberg Space Force Base in California or at NASA’s Kennedy Space Center in Florida.
It resembles a miniature version of NASA’s retired space shuttle orbiter, with wings, deployable landing gear, and black thermal protection tiles to shield its belly from the scorching heat of reentry. It measures 29 feet (about 9 meters) long, roughly a quarter of the length of NASA’s space shuttle, and it doesn’t carry astronauts. The X-37B has a cargo bay inside the fuselage for payloads, with doors that open after launch and close before landing.
The Space Force made a surprise announcement on November 8 that the next flight of the X-37B, sometimes called OTV-7, would launch on a SpaceX Falcon Heavy rocket. All six of the spaceplane’s past flights launched on smaller rockets, either United Launch Alliance’s Atlas V or SpaceX’s Falcon 9.
The Falcon Heavy can lift about three times the payload mass as a Falcon 9, but it has the same payload volume. The X-37B’s wingspan and length are fixed and known. This mission will include a service module mounted to the rear of the spaceplane to carry additional hardware, but the last X-37B had the same add-on and still didn’t need a Falcon Heavy.
Knowing this, and armed with the military’s admission this mission would explore new orbital regimes, outside observers surmised the military could be sending the X-37B to a higher altitude on the next flight.
The evidence points to this being the case. Airspace and maritime hazard notices released to warn pilots and sailors to steer clear of the rocket’s flight path suggest the Falcon Heavy fly northeast from Kennedy Space Center rather than the Falcon Heavy’s typical flight path to the east. The rocket’s two side boosters will return to land at Cape Canaveral, where SpaceX will refurbish them for another launch next year with NASA’s Europa Clipper science mission to study one of Jupiter’s icy moons.
The Falcon Heavy’s center core will fall into the Atlantic Ocean east of North Carolina, while the upper stage will continue propelling the military’s spaceplane into orbit. Then, the mission will enter a military-imposed news blackout. We don’t expect any more official updates on the progress of the launch or information about the X-37B’s progress until it eventually comes back to Earth.
Another maritime navigation warning covering an area of the Pacific Ocean south of Alaska also appears to be linked to this launch and likely delineates the area where the Falcon Heavy’s upper stage will reenter the atmosphere after deploying the X-37B. Most of the spent upper stage will burn up in the atmosphere. If this is related to the military spaceplane launch, the warning suggests the Falcon Heavy will ultimately release its payload into an elliptical, or egg-shaped, orbit ranging tens of thousands of miles above Earth, according to Marco Langbroek, an expert in satellite tracking.
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I have again updated my blogpost on tonight’s #USSF52 launch of the #X37B spaceplane mission #OTV7.
The update reflects some new insights leading to a revision of my orbit estimates.https://t.co/1Y7T6IcTcZ pic.twitter.com/VtCA0fLNyW— Dr Marco Langbroek (@Marco_Langbroek) December 11, 2023
This would require at least two burns by the Falcon Heavy’s upper stage, with the second engine firing steering the X-37B into a high-inclination orbit, perhaps tilted at an angle of 70 degrees or more to the equator. This would give the X-37B, and whatever it carries onboard, sustained views over the polar regions, whereas the spaceplane’s earlier missions covered ground closer to the equator.
During the past flights of the military’s spaceplane, hobbyist skywatchers could track the spacecraft’s orbit. The spaceplane was easily visible around dawn and dusk, but this time, the X-37B could be soaring much higher and not as readily observable from the ground with the naked eye.
“It will be interesting to see in what orbit it eventually goes, although with all uncertainty, it might be difficult to locate once on-orbit,” Langbroek wrote on his website.
Here’s what else we know about the X-37B’s seventh flight. This mission will “expand the envelope” of the spaceplane’s capabilities with “multiple cutting-edge experiments for the Department of the Air Force and its partners,” said Lt. Col. Joseph Fritschen, the X-37B program director.
These experiments include investigations into new “space domain awareness technologies,” the Space Force said. Space domain awareness refers to the military’s ability to know what other entities, ranging from commercial operators to potential adversaries like China, are doing with their spacecraft in orbit.
“These tests are key to ensuring safe and responsible operations in space for all users of the space domain,” the Space Force said.
The X-37B also carries a NASA experiment to expose plant seeds to the harsh radiation environment of long-duration spaceflight. While the NASA payload is almost certainly a secondary objective for this mission, Weeden said the presence of a radiation experiment gives some legitimacy to suggestions this mission will fly farther from Earth. “That kind of lines up with an orbit that kind of goes through multiple altitudes and multiple parts of the Van Allen Belts,” he told Ars.
Some observers, including Russia and China, have claimed the X-37B might be a weapons platform or could approach other satellites in orbit for inspection. There’s no evidence this has occurred on the X-37B missions to date, according to the Secure World Foundation. China has twice launched its robotic spaceplane that appears to be similar in size and shape to the X-37B.
“I’ve been saying for several years now that the most likely mission for the X-37B is to flight test new sensor technologies and new in-space hardware, solar panel technologies, all that kind of stuff,” said Weeden, who worked on space and missile programs in the Air Force, but not the X-37B.
Examples of experiments the X-37B has flown on prior missions include electric thrusters and advanced thermal control technologies. Past X-37B missions have also deployed small satellites, both covertly and overtly.
Putting the X-37B into a higher orbit could be a natural extension of these previous trials and experiments. The Pentagon is transitioning away from legacy military satellite programs, in which small numbers of billion-dollar spacecraft were tasked with supplying communications and tracking missile threats. In their place, the military is developing new constellations of dozens to hundreds of less expensive satellites to do the job, often in different orbits.
“Maybe there’s some of that experimentation (on the X-37B) tied to, ‘OK, let’s actually fly this kind of sensor in this kind of orbit and see how effective it is,” Weeden said.
It’s also possible this X-37B flight carries an electric propulsion system—like the one tested on a prior flight of the spaceplane—to drastically reshape its orbit after launching on the Falcon Heavy rocket. This could help the spaceplane spiral out to an even higher orbit or help bring it back to a lower altitude to enable a gentler reentry at the end of the mission.
“There’s such hyperbole around the X-37B,” Weeden said. “I don’t think the DOD [Department of Defense] is doing itself any favors by, on the one hand, publicly talking about it and hyping up how amazing it is, and how revolutionary it is, but then not providing any details at all about what it’s actually doing.
“Conversely, we’ve now seen China do a couple of test flights of its Shenlong [spaceplane], which appears to be very similar to the X-37B, and we’re seeing the US military get hyperbolic about that, about it’s a potential weapon, and we don’t know what it is, and it could be a threat,” Weeden said.
2-for-1 Tuesday
The Falcon Heavy launch with the X-37B spaceplane will get more attention, but it’s not the only SpaceX flight on tap Tuesday night. A few miles south of the Falcon Heavy launch pad, SpaceX is readying a Falcon 9 rocket for liftoff at 11:02 pm EST (04:02 UTC) with another batch of 23 Starlink Internet satellites.
These two launches will be the 94th and 95th of the year for SpaceX, including two test flights of the company’s giant new Starship rocket from Texas. SpaceX is on pace for around 100 launches this year, which would meet a goal set out by Elon Musk, SpaceX’s founder and CEO. The company aims to raise that to 144 launches in 2024, an average of about 12 missions per month.
If both rockets take off as scheduled Tuesday night, it would be the shortest time between launches in SpaceX’s history—at 2 hours and 48 minutes. It would also be the shortest turnaround between two orbit-class launches from Cape Canaveral since 1966.
The saying goes that records are made to be broken, and with the launch cadence making the Cape Canaveral spaceport sometimes feel like an airport, we’ll probably be reporting on another launch doubleheader soon.
Dec. 11, 2023: This story was updated to reflect the delays in the Falcon Heavy and Falcon 9 launches Monday night.