Whether in real life or Kerbal Space Program, the holy grail of spacecraft is the single stage to orbit vehicle, or SSTO for short. Such a vehicle would, for obvious reasons, be the pinnacle of reusability.
SSTOs were widely pursued in the 1990s, for example, by NASA and Lockheed Martin developing the X-33. That program, like many others, was canceled due to technical difficulties. With technology having advanced and matured since then, could it be time to give it another shot?
On January 19, Radian Aerospace announced that they'd raised $27.5 million of venture capital to start developing what they claim to be the first crewed SSTO, the Radian One. The small startup, based in Renton outside Seattle, has been in “stealth mode,” focusing on conceptual design and only developing a few critical technologies.
Unlike the space shuttles of the past, Radian One will take off horizontally and conserve fuel on takeoff; a sled will be used in a way comparable to how aircrafts are launched off aircraft carriers. G-forces will be low, making the flight comfortable and safe reducing passenger training. The One will then enter low-earth orbit and stay there for up to five days, performing assigned missions.
These missions include the ability to deliver and retrieve supplies and personnel to and from public and private space stations and retrieve, refuel, and service satellites. Beyond supporting the space agencies and industries of the world, Radian also envisions the new aircraft as a fast means of traveling around the globe, with a capability of taking either passengers or cargo of below 5000lbs to any place on earth in less than an hour(!).
Upon completing its mission, the spacecraft will land on a regular runway if desired to do so. Their long-term vision is to operate as regularly as an airline, something in part made possible by a turnaround time of 48 hours.
“Over time, we intend to make space travel nearly as simple and convenient as airliner travel,” says Richard Humphrey, Radian's chief executive and co-founder.