NASA resolved to abandon its space shuttle in 2011, but a mysterious company hopes to breathe new life into the concept.
Among the multitude of private companies that have embarked on the adventure of aerospace, Radian has long been one of the most mysterious little thumbs. She has finally just published the subject of her work, spotted by Interesting Engineering: she is working on an ambitious project for a fairly revolutionary horizontal take-off aircraft.
First particularity of this machine: its shape, halfway between the Concorde and the space shuttle. A design far removed from more traditional rockets, including SpaceX’s groundbreaking reusable rockets. And for good reason: as you have probably guessed from its wings, this machine is designed to take off horizontally, a bit like an airliner.
A rather exotic approach
This is a concept that is not new and that we already find in many more or less viable projects. But in practice, these machines do not run the streets. At present, the only functioning machines in this category belong to Virgin Galactic, which caused a stir in shipping its CEO to the frontier of space last summer.
But despite this precursor status, Virgin’s ship has many drawbacks. For example, he is not able to take off alone; he needs the help of a second vehicle capable of carrying the first to high altitude. Same observation for this good old space shuttle was absolutely unable to take off alone and had to be attached to a vertical launcher.
Radian’s craft, on the other hand, is very different. It is not only designed to take off horizontally, but it is also an SSTO, or Single Stage To Orbit. This acronym means that the device is designed to reach orbit in a single step, unlike all current commercial devices.
If you’ve ever attended a launch, you’ve certainly found it to be a well-oiled choreography. After takeoff, the machine usually gets rid of all superfluous equipment along the way, including empty fuel tanks and engines – much like a marathon runner throwing away his empty water bottle. This approach makes it possible to lighten the machine and therefore optimize engine performance, which is an absolutely fundamental problem in aerospace.
One floor, zero worries
But for SSTOs, the reverse approach is preferred. Instead of dismantling the machine in mid-flight and trying to recover the remains as best they can, these machines take their entire package with them. Inevitably, this implies some sacrifices in terms of performance; by definition, an SSTO can never be as efficient as the traditional model. This technology therefore seems rather ill-suited to the current context; for example, the almost complete recovery of the material is already almost part of the routine at the house of SpaceX.
But that doesn’t mean it’s all tossed around in this concept; a lot of water has flowed under the bridge since NASA abandoned the idea in 2011. SSTOs indeed have many logistical advantages that could weigh heavily in the balance thanks to new innovations in this sector. Because the real particularity of this concept is that it could work without the colossal infrastructure essential to the launch of a rocket.
Indeed, the Radian One could depart from any airport runway like a standard aircraft! It would begin by taking off using three liquid propellant engines. Once at altitude, it would then fire its rocket engines in order to garner the speed needed to reach orbit.
Once its mission accomplished, it would also be able to perform the reverse route, provided it had a long enough landing strip (~3km minimum). All that would then remain was to refuel the machine in order to allow it to set off again. And all without having left a single piece on the way.
Resurrection or last stand?
Eventually, Radian hopes that his machine will be able to fulfill the role that once seemed promised to the Space Shuttle: that of a routine utility vehicle, capable of serving commercial space stations like the ones Jeff Bezos wants to build.
Radian hopes to be able to offer operational gear before the end of the decade; it will be very interesting to see if SpaceX’s progress on recycling and recapture will eventually render the concept of the SSTO obsolete once and for all, or if the concept will find its audience by then.