CAPE CANAVERAL, Fla – It was one of the rocket designs that appeared during the early days of the space age, a concept that now appears to be given a second life at NASA’s Kennedy Space Center in Florida. It also saw a variant of the concept appear during the early days of the NewSpace movement. What is it? A spacecraft – with rotor blades.
Engineers are currently investigating whether or not spacecraft with rotors like a helicopter could be a viable way to slow spacecraft returning back to Earth. These rotors could potentially be used in place of the parachutes that are used in capsule-based spacecraft.
It is thought that this system could impart the stability and control that helicopters possess onto the Orion Multi-Purpose Crew Vehicle (MPCV). The system would not be powered; instead it would be moved by the force of the wind moving over the rotors. This process is called auto-rotation and while proven in rotary-wing aircraft, it has never been tried on a returning spacecraft.
Models are being constructed and drop-tested within the cavernous Vehicle Assembly Building or “VAB” located at NASA’s Kennedy Space Center in Florida. The procedure is a far cry from what the public generally thinks of when they think of a NASA tests.
According to NASA.gov, team members spread out on various levels inside the VAB and dropped a two-pound model from 480 feet up inside the expansive building. Using a helicopter remote control, a team member adjusted the rotor’s pitch, slowing the model several times as it descended to a landing atop a foam stack.
While, at first blush, this might seem a simplistic and unreliable method in which to test the viability of a design, it provides engineers with the basic knowledge of whether-or-not a design is worth pursuing.
If the concept proves sound, it still has a long way to go before it is entrusted with the lives of crew. Future tests could see a test article hoisted into the air via balloon and then released. A further test could see a small capsule return to Earth using the rotor system from the International Space Station (according to the article on NASA.gov this test flight would use science samples as cargo).
“The purpose of the testing we’re doing here is to study how to get the rotor starting to spin,” said Jeff Hagen, an engineer at Johnson Space Center in Houston. “We’re trying to build as much of that story as we can.”
This could possibly lead to spacecraft that could land virtually anywhere. NASA looked at all the different locations where helicopters land today and envisioned spacecraft that were capable of landing in those same areas.
The rotors would only be one component in a broader system. Fins, like those used on bombs and missiles, would also be incorporated into the capsule’s design, they would be deployed to help stabilize the Orion spacecraft, to prevent the capsule from rotating along with the rotor blades.
Rotors might even be used in spent rocket stages. As it stands now, these spent boosters reenter the Earth’s atmosphere and burn up. Boosters with rotor blades as part of their design could, potentially, return home and the expensive engines could be salvaged.
“A hundred years ago, there were cameras and there were phones and there were wireless devices to send Morse code and they were all separate technologies on their own,” said Les Boatright, an engineer at Kennedy. “Now you have a telephone that does all three of those things and it’s a merger of technology. Well, this is taking the capsule entry technology and helicopter rotor technology and merging those in an innovative way to make something that didn’t exist before out of two things that did exist before.”
This effort by NASA to test the viability of this system has, as mentioned above, been proposed before. As reported on Vintage Space, this concept was proposed during the Apollo era.
So why were rotors not used on Apollo spacecraft? Time. With the race to the Moon with the Soviets, the system was deemed to have required too much time to develop and NASA went with the simpler parachute system.
The concept bore fruit in the early 1990s when a small company based out of Mojave, Calif., built a spacecraft that employed a rotor. The Rotary Rocket Company built the Roton rocket that would have had tip jets. These would have been used to get the spacecraft through the densest part of the atmosphere, when the air became too thin it would have used a rocket engine the rest of the way to orbit with the rotor serving as an enormous turbopump.
Orion is being developed by NASA along with the space agency’s Space Launch System heavy-lift booster to send astronauts to destinations beyond Earth’s orbit for the first time in over four decades.