Welcome to space, Air Force — the Marines have been here for years
President Trump's Space Force came as a shock and surprise to many, even if the U.S. Air Force isn't quite sure how to move forward with it. NASA's chief executive wants it. America's pop culture astrophysicist Neil deGrasse-Tyson says it isn't a weird move. Even the Trump-critical Washington Post says now is the time.
The Marines thought it was time more than a dozen years ago.
Only back then the thinking was using space to bridge the time it took to get Marine boots on the ground. Earth's ground. Writing for Popular Science, David Axe described this new way of getting troops to a fight as a delivery system of "breathtaking efficiency."
Small Unit Space Transport and Insertion, or SUSTAIN (as the Corps' idea wizards called it) was designed to be a suborbital transport vehicle that flew into the atmosphere at high speed 50 miles off the Earth's surface, just short of orbiting the Earth. There, in the Mesosphere, gravity waves drive global circulation but gravity exerts a force just as strong as on the surface. It's also the coldest part of the the atmosphere and there is little protection from the sun's ultraviolet light. These are just a few considerations Marines would need to take.
This is also much higher than the record for aircraft. Even balloons have only reached some 32 miles above the Earth, so this pocket of Earth's sky is an under-researched area that not much is known about. What the Marine Corps knows for sure is that going that high up means it doesn't have to worry about violating another country's airspace, and it can drop Marines on the bad guys within two hours.
The SUSTAIN craft would need to be made of an advanced lightweight metal that could be used in the liftoff phase but also handle the heat of reentry into the atmosphere. Each lander pod would hold 13 Marines and be attached to a carrier laden with scramjet engines and rocket engines to get above the 50-mile airspace limit.
Objects moving in Low-Earth Orbit (admittedly at least twice as high as the SUSTAIN system was intended) move at speeds of eight meters per second, fast enough to circumnavigate the globe every 90 minutes. But the project had a number of hurdles, including the development of hypersonic missiles, a composite metal that fit the bill, and the size of a ship required to carry the armed troops and their equipment.
At the time the project wasn't feasible unless ample time to develop the technology needed to overcome those hurdles was given to researchers. But if the SUSTAIN project was given the green light in 2008, maybe we'd have a Space Corps instead of a Space Force.