Safety officials finally have a good idea of what a big rocket explosion can do

Last week’s explosion of a New Glenn rocket at Cape Canaveral, Florida, was clearly a setback for Blue Origin and NASA, but it was a learning experience for safety officials looking to open up the spaceport to hundreds more launches per year.

The launch base on Florida’s Space Coast is gearing up for a flurry of new arrivals. SpaceX is building multiple launch pads for its super-heavy Starship rocket, which will operate within a few miles of launch pads operated by SpaceX rivals Blue Origin and United Launch Alliance. Two other companies, Stoke Space and Relativity Space, are also developing launch sites along a narrow stretch of coastline at Cape Canaveral Space Force Station.

All of them have, or will soon have, rockets burning methane or liquified natural gas, replacing legacy launch vehicles fueled by kerosene, liquid hydrogen, or solid propellants. There are good technical reasons for making the switch, but until last week, engineers had scant real-world data on the damage that millions of pounds of methane and liquid oxygen would cause if a fully loaded rocket exploded on the launch pad or soon after liftoff.

By 2036, the Space Force projects that the spaceport could support up to 500 launches per year, five times last year’s total. The combination of these lofty launch forecasts and the Space Force’s conservative safety protocols has caused some tension at the Cape Canaveral spaceport.

Competitors of SpaceX have worried that daily launches and landings of the company’s reusable super-heavy Starship rocket might force evacuations of their own facilities for safety reasons. The US Space Force, which runs the spaceport, maintains strict rules for methane/liquid oxygen, or methalox, rockets. Comparatively, kerosene and hydrogen are known quantities.

For now, military officials are treating any methalox rocket with “100 percent TNT blast equivalency” and maintaining wide keep-out zones around their launch pads when the rockets are loaded with propellant. Their intention is to ensure the safety of the public and workers at the spaceport. With more data on how methane-fueled rockets explode, officials expect the keep-out zones to get smaller over time. To this end, NASA, the Space Force, and SpaceX have conducted sub-scale ground tests to gather measurements on methane’s explosive yield.

Artist’s illustration of Starships stacked on two launch pads at the Space Force’s Space Launch Complex 37 at Cape Canaveral, Florida.

Credit: SpaceX

Real-world data

The 100 percent blast equivalency policy was in effect at Cape Canaveral last Thursday, when Blue Origin loaded its New Glenn booster full of methane and liquid oxygen at Launch Complex 36. The smaller second stage was filled with liquid hydrogen and liquid oxygen as Blue Origin’s launch team counted down to a brief test-firing of the rocket’s seven BE-4 engines.

A fireball enveloped the rocket as the engines lit, destroying the launch vehicle and much of the launch pad. The explosion knocked Blue Origin’s only launch facility out of commission. The company says it aims to repair the site and resume launching by the end of the year, but past launch pad rebuilds have taken at least twice as long. It took SpaceX about 15 months to return one of its launch pads to service after a Falcon 9 rocket exploded during a similar test in 2016. That event was not as powerful as the Blue Origin incident last week.

“New Glenn is the biggest rocket we’ve launched here off the Eastern Range, and with that, it had the most fuel,” said Col. Brian Chatman, commander of the Space Force unit that operates the Cape Canaveral spaceport. “That makes it the largest explosion that we’ve had out here.”

There were no injuries to any personnel. The explosion destroyed Blue Origin’s transporter-erector that supports the rocket during horizontal rollout and raises it vertically on the pad. Blue Origin says it won’t replace the transporter-erector and will instead employ an “alternative vertical conop” (concept of operations) when it resumes New Glenn operations at Launch Complex 36, which the company leases from the Space Force.

Exploding rockets are nothing new in the launch business. Launch vehicles routinely blew up on the launch pad in the early years of the Space Age. The only rocket bigger than New Glenn to fail with a full load of fuel on or near its launch pad was the Soviet Union’s N1 rocket more than 50 years ago.

The Blast Danger Area (BDA) for last week’s ill-fated New Glenn test—based on the assumption of 100 percent blast equivalency—spanned a diameter of 7,174 feet, or an average distance of 3,587 feet from the pad, according to the Space Force. That is approximately two-thirds of a mile. All personnel were evacuated from this area before Blue Origin started fueling the rocket.

The farthest debris found so far was thrown a half-mile from the launch pad, Chatman said. He said engineers collected “phenomenal data” from the explosion, and officials will use the measurements to improve models on methalox rocket explosions. “As the teams are now going out and looking at the surrounding area, we’ll have a good feel for what overpressure impacts look like across the range and what that explosion looked like in and around the area,” Chatman said.

“Blue Origin also had some sensors and collected some data inside their integration facility and is working in lock step with the government, both on the Space Force side and on the NASA side, to help us evaluate and work that data into our models.”

SpaceX’s combined Starship and Super Heavy booster is the only methane-fueled rocket larger than New Glenn with plans to launch from Cape Canaveral. Starship already flies from SpaceX’s private base in South Texas, which operates under guidelines set by the Federal Aviation Administration. The only launch facilities there are owned by SpaceX, eliminating any concern about interference with competitors.