Thanks to a lead from Ars Technica's Rocket Report this week, we learn that SpaceX has won approval to build a plant to extract and liquefy both Oxygen and Nitrogen from air.
Cameron County has given SpaceX the green light to build an air separator facility, which will be located less than 300 feet from the region’s sand dunes, frustrating locals concerned about the impact on vegetation and wildlife.
The commissioners voted, 3-1, to give Elon Musk’s rocket company a beachfront construction certificate and dune protection permit, allowing the company to build a modern-day factory akin to an oil refinery to produce gases needed for space flight launches.
The plant will consist of 20 structures on 1.66 acres. The enclosed site will include a tower that will reach 159 feet, or about 15 stories high, much shorter than the nearby launch tower, which stretches 480 feet high. It is set to be built about 280 feet inland from the line of vegetation, which is where the dunes begin. The factory will separate air into nitrogen and oxygen. SpaceX utilizes liquid oxygen as a propellant and liquid nitrogen for testing and operations.
Saying the facility is "akin to an oil refinery" is a rather wrong picture as I understand the process. It's an air compressor that compresses air sucked into a cylinder which is then cooled to remove the heat added in compressing the gasses, causing the air to liquefy. The resultant liquid air is separated into O2 and N2 by controlling the temperature carefully around the boiling points, letting one boil off as the other remains liquid.
If you've watched operations around Starship test flights you might have a feel for how much LOX and LN2 they need for launches; I thought I had a feel for it but I was surprised. SpaceX says they need more than 200 trucks of liquid nitrogen and oxygen delivered for each launch. I know I've seen several trucks at a time going through the side gates into the area around the launch mount but saying 200 trucks worth surprised me. Think of the fuel that gets consumed just getting those trucks to SpaceX's area on the island from where the current provider liquefies the gasses.
With their application, SpaceX submitted a plan to mitigate expected negative effects on 865 square feet of dune vegetation and 20 cubic yards of dunes, as well as compensate for expected permanent impacts to 7,735 square feet of dune vegetation and 465 cubic yards of dunes. While the project will be built on property owned by SpaceX, the county holds the authority to manage the construction that affects Boca Chica's dunes.
Of course, the liquid oxygen is used as the oxidizer in SpaceX's methane/oxygen (methalox) system - both Starship and Super Heavy. They also use liquid nitrogen in many places around the operation; testing and other operations.
April 5th, 2024 Super Heavy static firing. LOX and Methane
burning, with LN2 in many places. Image
credit: SpaceX
About time. That will cut down a lot on tanker traffic.
ReplyDelete