The reusability challenge: economics, not technology

Shortly before 1 a.m. on the morning of July 18, a Falcon 9 first stage descended through the skies above Cape Canaveral, Florida, after launching a Dragon cargo spacecraft. A series of engine burns brought the stage down on a landing pad just south of the launch site, as sonic booms echoed across Florida’s Space Coast to herald its arrival.

The landing was the fifth time in seven months that SpaceX had successfully recovered a first stage. Prior to the launch, Hans Koenigsmann, a SpaceX vice president, said the company was in discussions with a potential customer for the first launch on a reused first stage, perhaps this fall. Blue Origin, meanwhile, has been flying its reusable New Shepard suborbital vehicle, which launched for the fourth time in June with minimal maintenance between flights.

To many, those accomplishments might suggest the arrival a new era of reusable rocketry. Yet, a panel of industry experts, speaking at a recent American Institute of Aeronautics and Astronautics (AIAA) conference in Salt Lake City, seemed to have some doubts, based more on economics than technology.

“Today’s technology does appear capable of addressing the known tech issues associated with the reuse of ballistic systems,” said Ben Goldberg, a senior director of science and engineering for Orbital ATK’s propulsion systems division. He discussed models he developed about the technology and economics of reusability.

However, he seemed skeptical that reusability, as currently being approached, would do much to lower costs. “You’re not going to get 100-fold,” he said, referring the magnitude of cost reductions. “You’re going to get 30 percent. That’s what all these models show.”

Goldberg said tweaking the model, including how the vehicle is recovered and how often it’s reused, doesn’t help much. “These numbers aren’t going to change by an order of magnitude,” he said. “That’s the state of where we are today.”

In the future, he suggested “technology and disruptors” might enable steeper decreases in costs. Another panelist agreed. “We’re laser-focused on building our Alpha launch vehicle,” said Tom Markusic, chief executive of Firefly Space Systems, referring to small expendable launch vehicle his company is developing. “But every company has to have a vision.”

Markusic’s vision for a future reusable launcher involved winged vehicles, rather than the vertically landing boosters Blue Origin and SpaceX have demonstrated. “We should soup up airplanes. We should build rocketplanes with increasingly more advanced propulsion systems,” he said, including the use of ramjets and scramjets. “It can provide a much better path to reusability and lowering cost to space than the conventional ‘lunar lander’ type of approaches that others are taking right now.”

The panelists have a point: while companies are demonstrating that launch vehicles could be reused, the economics of reusability are still uncertain. Goldberg’s estimate of a 30 percent decrease in price matches what SpaceX President Gwynne Shotwell said earlier this year, when asked what discount the company would offer for Falcon 9 missions with a reused first stage.

That doesn’t seem like much, but at least companies are actively working on those vehicles, rather than describing visions of the future or refining models. Notably absent at the AIAA panel were representatives of Blue Origin and SpaceX: panel moderator Dan Dumbacher said they were invited, “but were unfortunately unable to attend because of other commitments.”

Maybe they were busy working. Just a few days after the panel, SpaceX did a successful “full-duration” — about two and a half minutes — test fire of one of its recovered Falcon 9 stages at its Texas test site. That may offer a better handle on the state of reusable launch vehicles than a PowerPoint presentation, anyway.