Imagine strapping a giant rocket engine on the International Space Station (ISS), inflating a few balloon-like structures to hold your luggage, and adding a spinning carousel-wheel for artificial gravity.
This ungainly-sounding assemblage, dubbed Nautilus-X, (“Non-Atmospheric Universal Transport Intended for Lengthy United States eXploration”) has been proposed by the NASA Technology Applications Assessment Team at the Johnson Space Center in Houston, Texas. The group is chartered with examining key technologies that can advance space exploration in a timely and affordable manner.
The designers optimistically believe that such a planet-roaming “space station with rockets” could be ready by 2020 at a cost of under $4 billion. If this number is realistic, the vehicle would be cheaper than the projected costs for the “Apollo-on steroids” Orion capsule.
NASA has already spent approximately $5 billion on Orion since 2006, and will need roughly another $6.6 to 7.1 billion to meet a 2015 launch.
The real ISS could be used to test components of the Nautilus, and no doubt the experience with the ISS would provide applicable spin-off technology.
Like building a house with room for additions, the Nautilus has a modular design that can expand with mission requirements. The central core is a linear truss with a 40-foot diameter giant rotating inner tube structure that serves as the low-gravity habitat. A nuclear, chemical or solar-electric propulsion system could be bolted at one end of the truss.
The trickiest piece of engineering is the inflatable spinning torus that would provide partial artificial gravity. The ring would need to spin at 10 RPM to provide a force one-half Earth gravity. The bearings, slip rings for power, liquid metal seals, and counter-rotating flywheel would be an engineering challenge. A scale working model of the centrifuge would be externally attached to the ISS for testing.
Various inflatable modules would be attached to the truss to provide maximum volume for supplies and storage. Like the ISS, the vehicle would have multiple docking ports for various spaceships. An onboard radiation “storm cellar” lined with liquid water or hydrogen slush would provide shielding from solar flares that would irradiate the vehicle.
But several additions don’t make sense to me. First, there are hangars for landing vehicles for use on asteroids or the Martian surface. To significantly lower mass and therefore reduce transit time, why not simply send unmanned landers ahead and put them into a parking orbit to wait until the crew arrives.
The Nautilus has a huge deep-space antenna where laser transmission may make more sense. It also has a shuttle-derived remote manipulator arm which also seems like excess weight.
Over the past several decades there have been a wide variety of designs for interplanetary manned vehicles. The simplest are inflatable so-called Transhab modules strapped onto a nuclear propulsion stage. The most imaginative was a parasol-looking nuclear electric-ion propelled Mars vehicle, designed by rocket engineer Ernst Stuhlinger in 1954, that had a huge saucer-shaped heat radiator.
The Nautilus would be fully assembled and tested on the ISS. Two or three heavy lift booster launches would be needed to deliver the pieces to the ISS for assembly and integration.
The vehicle could go to Mars with a six-person crew, or fly out to the Earth-Moon Langranian point L1 to serve as a base, or visit an asteroid.
L1 would be a great staging point for launching manned lunar landers. Just don’t tell Congress this is funding for yet another space station — albeit one that can change zip code.
As Volkswagen use to say about their classic Beetle: “it’s ugly but it get you there.”