The purpose of this agreement is to build ships that could deliver people and cargo anywhere on Earth or into space within three hours. The Pentagon needs shuttles to increase the speed of response to emerging threats.
In the early 2000s, the Dream Chaser space glider was supposed to be created in passenger and cargo versions. The designers carefully studied the American Space Shuttle, which stopped flying in 2011, and even visited Russia, where they were introduced to the BOR-4 reusable spacecraft project. "Dream Runner" outwardly almost a complete copy of it.
To reduce weight, the body of the American device is made of composite materials with ceramic thermal protection. The current version of Dream Chaser is cargo. It has a pressurized compartment and a shooting cargo module Shooting Star ("Shooting Star"). In general, the shuttle is capable of lifting over 5 tons of cargo into low Earth orbit, and returning about 1.8 tons. Another 3.4 tons are placed in the module, which is dropped before entering the atmosphere and burns up. This is how waste will be disposed of. Sierra Nevada, of which Sierra Space became a division, has already awarded a seven-flight resupply mission to the International Space Station from NASA starting in 2023. By this time, the Dream Chaser is planned to be ready to carry passengers as well. The future passenger version will be able to deliver up to seven people into space in a pressurized compartment.
The Dream Runner is planned to be launched into space by Vulcan and Atlas-5 rockets. Unlike the Space Shuttle, which was attached to the side of the booster body, the Dream Chaser will sit on top of the first stage. It was this arrangement with the carrier that the Soviet designers adhered to. Landing - horizontal, aircraft is carried out on any runways, the length of which should not be less than 2.5 kilometers.
The US military has been exploring the possibility of moving the military and their equipment on spaceships for more than half a century. So far, all the available proposals did not satisfy them - too expensive and unreliable. But the dream does not leave the generals. After all, the C-17 Globemaster III military transport aircraft takes at least 15 hours to reach the far corners of the globe. Sea transport - generally weeks. It's tempting to get a delivery vehicle that only needs a couple of hours at the most.
The US military does not disclose its expectations for the payload of military shuttles. It is obvious that they can count on the full load of the "Running", all five tons, only in the case of launching cargo into orbit. But when the military and weapons are transferred from one point of the planet to another, serious weight restrictions come into force.
Probably, the current limit of seven crew members can be pushed back and the redeployed contingent can be increased. But the total tonnage of 1.8 tons allowed for landing is a hard limit. And this is not very much for military operations. The transfer of tanks, armored vehicles, artillery is out of the question. In this case, the lifting capacity required is hundreds of tons.
The new shuttle cannot handle such weight categories - the Dream Chaser is a quarter smaller than even the decommissioned Space Shuttle. Its relatively small payload makes transporting military personnel and supplies under any circumstances impractical and uneconomical.
In addition, having delivered cargo to an airfield with a sufficiently long runway, the shuttle will not be able to return to its starting point on its own. And there are radically fewer spaceports in the world than airfields. Returning a transporter is not an easy task and not cheap.
But the deal between the Pentagon and Sierra Space still makes sense. This partnership of an almost unlimited military budget and the technical intelligence of the designers will enable the technology to be worked out for the larger and more powerful spacecraft that may appear in the future.