New Space Churn
A version of this article appears in the August 25 issue of Aviation Week & Space Technology.
As entrepreneurial “New Space” grows up, veterans of its early days are finding innovative ways to tackle old problems and enter emerging markets that did not exist when their industry was an infant—a decade ago.
Thomas E. Markusic, a propulsion engineer who cut his New Space teeth running Elon Musk’s flight-test center in Texas and later held senior posts atand Blue Origin, has kicked off a startup called Firefly Space Systems that is developing a low-cost Falcon 1-class launch vehicle to launch small satellites using a methane-fueled aerospike engine and composite cryotanks.
Going from a standing start early this year, Markusic and a handful of like-minded entrepreneurs have self-funded a rapid buildup to 30 employees. They have opened facilities in Austin, Texas, and Hawthorne, California (not far from the factory), and started buying fiber-winding gear for composite tanks to be built using an out-of-autoclave process tested at this summer. They have also bought land for a test site within commuting distance of Austin.
“One thing I learned at SpaceX, if you don’t have your own test site you’re not going to go anywhere, really,” says Markusic. “I wanted to keep everything co-located too. Austin allowed me the possibility to have a relatively closely co-located test site, so right now we’re in a suburb of Austin with our engineering offices, and we just bought a 215-acre test site in Briggs, Texas.”
The aerospike rocket-engine technology that Firefly will test at the Briggs site builds on the way a rocket’s plume expands as it ascends through the atmosphere. Without a bell-shaped nozzle to contain it, the plume basically assumes the most efficient shape for the ambient atmospheric pressure, allowing the engine to operate with greater efficiency.
The technology has been tried repeatedly over the years, and once was considered for the space shuttle main engine. The suborbital X-33 reusable launch vehicle prototype built by the Lockheed Skunk Works featured a ground-tested Rocketdyne XRS-2200 linear aerospike engine integrated into the lifting-body vehicle’s tail (AW&ST June 7, 1999, p. 57), and while that vehicle never flew, a team from California State University, Long Beach, and Garvey Spacecraft Corp. flew a small ethanol-fueled aerospike in September 2003.
In Firefly’s planned “Lumen” engine, which uses what is known as a plug aerospike configuration, a ring of 10 combustion chambers surrounds a truncated spike (see inset illustration). As the plumes from the combustors expand with the dropping ambient air pressure as the vehicle ascends, the interior parts of them push against the so-called plug to generate additional thrust.
“We come off the pad with, effectively, a 30:1 area ratio nozzle, which dramatically increases our performance,” Markusic says. “That’s the theory. In practice it doesn’t quite work that way. The aerospike actually goes through kind of a closed-wake and an open-wake regime, and you really don’t start seeing the benefits until the pressure starts going down a little bit in practice. But if you integrate over the whole boost trajectory you definitely see an enhancement.”
Just as Firefly is drawing on a lot of government research in its aerospike technology, the company is using a key element of the SpaceX Merlin engine—the pintle injector—in its new engine’s combustion chamber. Markusic, who jumped ship fromto SpaceX after the agency sent him to Kwajalein Atoll in the Marshall Islands to observe the first flight of the Falcon 1, says he started working on the technology—also used on the Apollo program’s lunar-descent engine —at SpaceX and when he was developing a liquid-fuel alternative to the hybrid engine used on Virgin Galactic’s SpaceShipTwo.
“A pintle injector is a great injector for a startup company because it’s bulletproof,“ he says. “There’s never been a pintle injector that’s been shown to be unstable.”
But while it is willing to borrow pintle technology from the Merlin and other engines, Firefly is using methane fuel instead of kerosene as a way to avoid the expense and operational difficulty associated with the helium used to pressurize propellant tanks. Helium is hard to contain, and SpaceX has learned the hard way that helium leaks can cause costly delays (AW&ST June 11, p. 22). With methane, Firefly is able to use a heat-exchanger built into the aerospike plug to boil both of the engine’s propellants—methane and liquid oxygen—for autogenous pressurization.
Methane gives higher engine-exhaust velocity than kerosene, but it is much less dense, which in a launch vehicle means more weight for the larger tanks needed to hold enough of it to get to space. To attack that problem, Firefly is working toward lightweight composite tankage and other structure, using engineers who honed their skills developing the composite structures on Virgin’s WhiteKnightTwo carrier aircraft. The company is also watching the results of composite tankage tests just wrapping up at Marshall Space Flight Center.
scuttled the X-33 program in part because an experimental composite liquid hydrogen tank failed during tests at Marshall in 1999. built the tanks used in the tests this summer using a new out-of-autoclave curing process, and Markusic—who worked at Marshall for five years—says he and his colleagues have been following the test series closely. Firefly has just signed a Space Act Agreement with NASA for help with the tank technology and other development issues.
SpaceX dropped its Falcon 1 program after three launch failures and two successful orbital flights, and moved on to the medium-lift Falcon 9. Firefly hopes to pick up where Musk left off, using a high flight rate and the mass production it enables to hold down the price of a launch with its two-stage “alpha” vehicle to $8-9 million. That would put 409 kg of payload into a circular 500-km equatorial orbit, or 218 kg into polar orbit at the same altitude. The goal is to tackle the smallsat launch market emerging on the coattails of advances in the tiny cubesat form factor, which has far more spacecraft built or in development than rides to space to accommodate them (AW&ST Aug. 4, p. 19).
“There are two fundamental approaches to lowering costs,” Markusic says. “The first is mass production, and the second one is reusability. To tap into this mass-production avenue, you have to have something to be mass produced. Now the only launch vehicle that can honestly be mass produced is a small launch vehicle, because that is the only kind of launch vehicle that has a lot of payloads. There is an availability of an order of magnitude more launches for small satellites than there is for large satellites.”
Firefly is “definitely set for the near term,” but its funding needs are moving deeper than the pockets of its founders. The principals have started fundraising in earnest, with “one hard commitment that will give us a multi-tens-of-million-dollar injection in about the next month [and] we have a couple of fairly solid leads,” Markusic says, noting that there is a shortage of places for investors who want to get into New Space to put their money.
“What we’re finding is that there’s a scarcity of investment opportunity,” he says. “People like the team we’re building, and like the idea that they can actually get some capital in and potentially have a high payoff.”