Reuse, Reliability Will Launch Future, Study Says
Driving down the price of taking people and cargo into space or to the other side of the world in two hours will depend on developing a system so reliable and reusable that a thousand flights or more can take place in a year, a space launch expert told a group of engineers and others Aug. 31 at NASA's Kennedy Space Center.
It's not a launch scenario envisioned for the immediate future, but it could develop in the decades afterward, Jay Penn of Los Angeles-based The Aerospace Corporation said during his "Beyond Next Generation Access to Space" presentation. The company studied potential business cases for pursuing different launch strategies.
The cost of taking a pound of anything into space ran about $10,000 aboard the space shuttle, but that price tag would fall dramatically if space agencies and companies model their research on developing launch systems on the commercial airline and air cargo industries, Penn said.
"Commercial aircraft operate at $2 to $3 per pound of payload around the world, but space is 5,000 times that," Penn said.
Getting the space transportation business down to that cost means building vehicles that are designed for operability – that is much less maintenance between flights with rapid turnaround to support much higher flight rates. Evolving systems that deliver people and cargo to anywhere on the planet in less than two hours, for example, will need to make multiple trips in the same day and operate out of three or more hubs around the world.
His study has shown that some new applications could emerge in the coming years to accelerate the demand for frequent and lower cost access to space. In fact, the development of such reusable and operable systems will require the promise of higher demand to justify their development. Among the markets that could provide that spark are orbital space tourism, even limited demand for space-based solar power generation, and high speed transport services to travel from point-to-point on the planet.
"That's where you need to spend your energy, to make aircraft-like operations for these kinds of vehicles," Penn said.
Kennedy, with unique facilities such as the Vehicle Assembly Building and a runway long enough to host space-going vehicles, could find itself in key support roles for the new spacecraft.
Jim Ball, the deputy of Kennedy's Center Planning and Development Office, said his office is leading the effort to craft a future development concept and revised master plan for KSC to position it for future needs. The plan will provide a guide for the overall development of the center for the next several decades, Ball said.
Penn's study was not necessarily a prediction of where the space launch industry will be in the coming decades as much as a look at what it could be. For now, NASA is focused on a budding commercial industry aiming to launch cargo and astronauts to the International Space Station. The agency is also working toward a launch and space infrastructure supporting astronauts on missions to an asteroid, the moon or Mars.
So what would the spacecraft look like that could accomplish an unprecedented flight rate? Well, it would have a large first stage booster with wings and landing gear so it could land on a runway. It would weigh about as much as today's jumbo jets but may be a bit smaller.
The booster's main engines would operate on existing fuels, either kerosene or liquid hydrogen and it might even make its own oxygen in flight. Penn emphasized using fuels that can be handled easily on Earth between flights, and both kerosene and hydrogen have a long history of safe handling and remote loading.
The second stage would be either a similar winged booster with a small cargo bay, or a second stage holding a satellite. If the design is versatile enough, then two first stage boosters could be combined to launch a particularly large payload.
Getting that kind of design will start with combining new technologies rather than trying to come up with a single revolutionary invention, Penn said. Pulse detonation engines powering a Waverider-type craft made from carbon nanotubes would be a possible combination.
Designers also must focus on modular concepts that give operators flexibility. But mostly, they need to come up with space-worthy craft that operate like airplanes, with one kind designed for space operations and another destined to fly in and out of the atmosphere without going into orbit for carrying passengers and cargo between destinations on earth.
"It's going to be very challenging to build one vehicle to do both roles," Penn said.
In both cases, Penn said it is not necessarily an advantage to design a spacecraft that takes off from a runway like an airplane because additional weight would mean the craft would weigh up to three times more than a 747 or A380.
There is also the prospect of space tourism, he believes, with most of the demand being for going into orbit instead of just going into space briefly.
"We think there's a sweet spot where you can have 1,000 flights a year and get the ticket prices down to the point where people will want to pay," Penn said.
His advice for the future development of KSC? Be flexible and ready to adapt to these potential future markets that could dramatically increase flight rates and spur the development of vehicle systems that require much faster turnaround, and efficient ground servicing.
NASA's John F. Kennedy Space Center