Enlarge/ A European ATV cargo freighter reenters the atmosphere over the Pacific Ocean in 2013.
Since the beginning of the year, landowners have discovered several pieces of space junk traced to missions supporting the International Space Station. On all of these occasions, engineers expected none of the disposable hardware would survive the scorching heat of reentry and make it to Earth’s surface.
These incidents highlight an urgency for more research into what happens when a spacecraft makes an uncontrolled reentry into the atmosphere, according to engineers from the Aerospace Corporation, a federally funded research center based in El Segundo, California. More stuff is getting launched into space than ever before, and the trend will continue as companies deploy more satellite constellations and field heavier rockets.
“The biggest immediate need now is just to do some more work to really understand this whole process and to be in a position to be ready to accommodate new materials, new operational approaches as they happen more quickly,” said Marlon Sorge, executive director of Aerospace’s Center for Orbital and Reentry Debris Studies. “Clearly, that’s the direction that spaceflight is going.”
Ideally, a satellite or rocket body at the end of its life could be guided to a controlled reentry into the atmosphere over a remote part of the ocean. But this is often cost-prohibitive because it would require carrying extra fuel for the de-orbit maneuvers, and in many cases, a spacecraft doesn’t have any rocket thrusters at all.
In March, a fragment from a battery pack jettisoned from the space station punched a hole in the roof of a Florida home, a rare instance of terrestrial property damage attributed to a piece of space junk. In May, a 90-pound chunk of a SpaceX Dragon spacecraft that departed the International Space Station fell on the property of a “glamping” resort in North Carolina. At the same time, a homeowner in a nearby town found a smaller piece of material that also appeared to be from the same Dragon mission.
These events followed the discovery in April of another nearly 90-pound piece of debris from a Dragon capsule on a farm in the Canadian province of Saskatchewan. NASA and SpaceX later determined the debris fell from orbit in February, and earlier this month, SpaceX employees came to the farm to retrieve the wreckage, according to CBC.
Pieces of a Dragon spacecraft also fell over Colorado last year, and a farmer in Australia found debris from a Dragon capsule on his land in 2022.
Enlarge/ A Falcon 9 rocket lifts off Thursday from Cape Canaveral, Florida.
Upgrades at SpaceX’s most-used launch pad in Florida got a trial run Thursday with the liftoff of a Falcon 9 rocket with a Dragon cargo ship heading for the International Space Station.
SpaceX’s Cargo Dragon spacecraft launched at 4: 55 pm EDT (20: 55 UTC) Thursday from Space Launch Complex 40 (SLC-40) at Cape Canaveral Space Force Station in Florida. This mission, known as CRS-30, is SpaceX’s 30th resupply mission to the space station since 2012.
The automated Dragon supply ship took off on top of a Falcon 9 rocket, heading for a monthlong stay at the International Space Station, where it will deliver more than 6,000 pounds of hardware, fresh food, and experiments for the lab’s seven-person crew.
In the last few months, SpaceX has outfitted the launch pad with the equipment necessary to support launches of human spaceflight missions on the Crew Dragon spacecraft. The Cargo Dragon capsule is the same size and shape as SpaceX’s Crew Dragon, but it’s filled with cargo racks and storage platforms rather than seats and cockpit displays.
This week, SpaceX technicians used the newly installed launch tower and crew access arm at SLC-40 to load time-sensitive experiments and supplies into the Cargo Dragon capsule atop the Falcon 9 rocket.
“CRS-30 will be our first Dragon to launch from Pad 40 since we put that brand-new crew tower in place,” said Sarah Walker, SpaceX’s director of Dragon mission management, in a prelaunch press conference.
Building new capability
Starting last year, construction crews at Cape Canaveral erected segments of a more than 200-foot-tall metal lattice tower at SLC-40, right next to the starting blocks for SpaceX’s Falcon 9 rocket. Before then, SLC-40 was based on a “clean pad” architecture, without any structures to service or access Falcon 9 rockets while they were vertical on the pad.
In November, contractors raised the crew access arm to an attach point near the top of the tower. This walkway will allow astronauts to crawl into the Crew Dragon spacecraft during a launch countdown. It also provides access to the hatch on the Cargo Dragon spacecraft for final cargo loading.
Earlier this year, SpaceX tested an escape chute at SLC-40 that would be used in an emergency to help astronauts and ground crews quickly get away from the pad. The chute is similar in function to slide-wire baskets in use for decades at LC-39A, but instead of riding a basket from the top of the tower, personnel escaping a pad emergency would slide down a chute to carry them several hundred feet from the rocket.
SpaceX employees tested the pad escape chute last month at SLC-40. Gwynne Shotwell, SpaceX’s president and chief operating officer, took the ride down the chute. “Astronaut and personnel safety is SpaceX’s highest priority, which is why I had to personally test the new slide,” she posted on X, alongside a wink emoji.
“The team took commercially available off the shelf technology and applied it to the crew tower,” Kiko Dontchev, SpaceX’s vice president of launch, wrote on X. “You are trained on it the same way you are trained on using an emergency exit door on airplane. Only takes a couple of quick physical actions to deploy the slide and anyone can effectively do it.”
As more people travel to space, particularly on larger vehicles like SpaceX’s Starship, simplifying safety systems will be important.
“This system will help us scale to bigger towers and spaceships (think 100 people on Starship),” Dontchev wrote.
SpaceX and its contractors completed all of this work as Falcon 9s fired off SLC-40 every few days with Starlink satellites and other missions.
For the last four years, all of SpaceX’s crew and cargo launches to the space station have departed from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center, a few miles up the coast from SLC-40. In 2018 and 2019, SpaceX outfitted LC-39A for Cargo Dragon and Crew Dragon missions ahead of the company’s first human spaceflight mission in 2020.
Walker said the new infrastructure added at SLC-40 is “nearly functionally identical” to the equipment for crew missions at LC-39A. The primary differences are the means of pad escape—the chute instead of slide-wire baskets—and a more robust elevator in the tower at SLC-40.
Previously, SpaceX used both SLC-40 and LC-39A for launches of its now-retired first-generation Dragon cargo capsules, which had their final supplies loaded before SpaceX raised the rocket vertical for launch. Like regular satellite launches on Falcon 9s, both pads could support the first-generation Dragon cargo missions.
“Thanks to this new state-of-the-art crew tower required for our human spaceflight missions, that late-load cargo operation got a massive upgrade, too,” Walker said. “It is much easier to load a huge complement of time-critical NASA science into our Dragon spacecraft in the flight orientation.”
SpaceX has drastically ramped up its launch cadence since building LC-39A for Dragon missions. The company plans nearly 150 Falcon 9 or Falcon Heavy launches this year. When you’re flying rockets every two or three days, it’s inevitable two missions will end up vying for the same launch slots. Most recently, that happened in February, when a NASA crew mission was ready to launch from LC-39A around the same time as a narrow launch window for Intuitive Machines’ first commercial lunar lander. Both had to go off of LC-39A.
“Historically, Pad 40 has kind of become our high rate pad,” Walker said. “We’ve gotten the time between launches down to just a couple of days.”
LC-39A has seen less use, primarily for Dragon crew and cargo flights, Falcon Heavy missions, and other “uniquely complex” missions like the Intuitive Machines lander, Walker said.
