WASHINGTON — Three U.S. government agencies are undertaking studies to look at the questions of safety related to a brand new generation of launch vehicles that use liquid oxygen and methane propellants.
At a May 15 meeting of the Federal Aviation Administration’s Industrial Space Transportation Advisory Group (COMSTAC), FAA officials described efforts which might be underway to grasp the explosive effects of that propellant combination within the event of a launch accident.
That propellant combination has been used on two launches of American vehicles up to now: Relativity Space’s Terran 1 on March 22 and SpaceX’s Starship April 20. It can even be used on engines that can power Relativity’s larger Terran R in addition to Blue Origin’s Recent Glenn, Rocket Lab’s Neutron and United Launch Alliance’s Vulcan Centaur.
Firms are drawn to liquid oxygen (LOX) and methane because it offers the next specific impulse, a measure of efficiency, and burns cleaner than LOX and kerosene, noted Brian Rushforth, the manager of the innovation division within the FAA’s business space transportation office. But, there’s little information in regards to the explosive potential of that propellant combination.
“We just don’t know the yield of the explosive enough from the FAA perspective, in order that’s why we’re conducting experiments,” he said on the COMSTAC meeting. The priority is that each LOX and methane are miscible, meaning that they readily mix together, increasing its explosive potential.
Understanding that explosive potential, he said, will support FAA work on public safety, resembling establishing hazard areas and refining calculations of the utmost probable loss that launch providers have to insure against.
The FAA has arrange a test stand on the Dugway Proving Ground in Utah. A crane 43 meters tall shall be used to drop stainless-steel containers containing mixtures of LOX and methane. A series of tests is planned to start out in June on three-week intervals to measure the explosive power of that propellant combination.
A second phase, tentatively scheduled for next yr, will conduct similar tests with various velocities. He said the information from those tests shall be shared with other government agencies, resembling NASA and the U.S. Space Force, together with launch vehicle developers.
That study is separate from one which NASA and the Space Force are working on discussed at a May 16 meeting of the human exploration and operations committee of the NASA Advisory Council. That work, agency officials said, is targeted on range issues, including the effect of LOX/methane launches on operations at other pads.
“It’s really to try to understand what, if any, mitigations we want to do for among the adjoining launch pads,” said Tonya McNair, deputy associate administrator for management in NASA’s Space Operations Mission Directorate. That work is being funded through NASA’s Launch Services Program, with some cost-sharing with the Space Force.
On the COMSTAC meeting, Rushforth said there may be some coordination between the FAA and NASA/Space Force studies to avoid gaps and overlap. He noted that NASA will use the identical tower for LOX/methane tests after the FAA completes its first phase of its test campaign.
He said that, for now, the FAA is taking a conservative approach in its safety analyses. “We don’t have a solid feel for the TNT equivalent of LOX/methane, so there may be a level of conservatism that we’ve introduced,” he said. “The hope is that, once we validate this, if we’re being too conservative we are able to lessen the necessities.”
