Sierra Space and Radian Are Developing Ultra-Fast Spaceplanes
If Mach 1+ sounds too slow for that transatlantic flight, how about Mach 22.5, or 17,400 mph? That may soon be an option, thanks to a fleet of spaceplanes readying to take flight.
While the latest generation of both supersonic and hypersonic aircraft mostly use jet engines and atmospheric oxygen for combustion, spaceplanes, generally speaking, also have wings but use rocket engines and carry O2 on board. They also reach speeds of at least 17,400 mph, the rate at which centrifugal force equals gravity. In non-engineering terms? Fast enough to leave the atmosphere and enter Low Earth Orbit (LEO).
Radian One in Low Earth Orbit.
Radian Aerospace
“The experience will be more comfortable and more like flying on a regular jet than a rocket,” says Richard Humphrey, CEO of Radian Aerospace, which has already flown a one-tenth demonstrator version of its coming spaceplane, Radian One. “And winged vehicles can perform in ways a typical rocket can’t. When a rocket slows down, it goes down, but one with wings can dip down and go back up, it can turn, it can invert.”
Sierra Space has reached the final phase of testing its Dream Chaser spaceplane, co-developed with NASA for missions beyond the stratosphere, and it will make its first flight in the second half of this year. Like the Radian, it will be reusable, with turnaround times ranging from two days (Radian) to a few months (Sierra).
Sierra Space Dream Chaser “Tenacity” is scheduled to make its first flight to the ISS later this year.
Sierra Space
After an initial focus on scientific research, including Sierra’s partnership with Jeff Bezos’s Blue Origins on developing a private space station, the Dream Chaser will be involved in commercial operations by hauling cargo and shuttling scientists and researchers to and from space stations.
Both Sierra Space and Radian also have space-tourism aspirations that go beyond much of what’s currently available, including 11-minute flights by Virgin Galactic and Blue Origin, and longer space-balloon flights by companies like Space Perspective and Zephalto that do not reach Low Earth Orbit. “Passengers will be able to go up and stay in orbit,” says Humphrey, whose company has the most developed passenger plans right now. “We can go around the planet in about 95 minutes, so a typical trip will probably be three laps.”
Visits to one or more of the six space stations currently under development lie ahead as well. “We’re calling it purposeful tourism,” says Angie Wise, Sierra’s chief safety officer and SVP of mission and quality assurance. “You’ll get the experience of going to space, but we’ll also put you to work helping with experiments.”
Radian’s PFV01 scaled prototype has made initial test flights.
Radian Aerospace
At the end of the trip, spaceplanes enjoy a quiet glide back to Earth and a gentler landing on commonly available runways, which opens another intriguing option—point-to-point travel around the globe.
“In that scenario,” Humphrey says, “we will travel out of the atmosphere briefly, at near orbital speeds [greater than Mach 10], and then re-enter and ‘fly’ down to a runway.” Virgin Galactic has hinted at similar plans for its new Delta-class spaceship.
New York to Sydney is roughly 10,000 air miles. At Mach 13, that would be a one-hour flight.
