To Longshot Space CEO Mike Grace, rockets are an “overly exquisite solution” to the problem of sending megatons of inert mass into space. Rockets are among the greatest marvels of human engineering.
In a recent interview, he stated, “You need something that is less intelligent and much cheaper to build and operate.”
Longshot’s solution is a kinetic launch system capable of reaching hypersonic speeds and firing projectiles at orbital velocities for less than a monthly Netflix subscription.
It is visually and conceptually distinct from its competitors, namely SpinLaunch, which is developing a spinning accelerator to propel mass into orbit, and Stratolaunch, which uses a large, specialized airplane to launch a hypersonic vehicle in midair.
The primary distinction is that Longshot’s system is extremely horizontal. It is not technically a cannon because it lacks an ignitor; rather, compressed gas forces a wedged projectile through a very long concrete tunnel that is essentially a vacuum chamber. The resulting rates are extremely quick, and they increase proportionally with system size.
Thus, a system capable of Mach 5 will be approximately 80 feet long; a system capable of Mach 10 will be the size of two or three football fields; and systems capable of reaching space at Mach 25 to 30 will be on the order of multiple kilometers in length.
Longshot aims for a very low cost of orbit, as low as $10 per kilogram (compared to the $6,500 per kilogram cost of a Falcon 9 ride-share). According to the company, it is only feasible to maintain low prices by keeping as much of the system as possible on the ground. E
nergy is dispersed across space and time; liberated from the requirements of vertical lift, such systems can be constructed out of concrete instead of aluminum.
However, there is no such thing as a free lunch, particularly in the aerospace industry, and Longshot’s low prices will come with significant drawbacks.
The first is the footprint on the land. In addition to the compressed gas pumps and tunnel, Longshot’s system incorporates an on-site solar farm, which will undoubtedly help keep costs low but increase the overall land-use requirements.
The second compromise is pollution. At these dimensions, the Longshot system will generate an extraordinary sonic explosion. Given that the company will be able to reuse the system as rapidly as it can draw a vacuum in the tunnel, this could result in a significant number of sonic booms per day.
Due to these two factors, the system must be located in an extremely remote location, such as the Australian wilderness or the arid regions of Kenya.
“You would want to be somewhere where an atomic bomb could go off and nobody would notice,” Grace said.
If humanity ultimately realizes its desire to colonize the solar system, these trade-offs may prove to be relatively insignificant. Grace noted that Hawaii imports 13 million tons of goods, including food, fuel for automobiles, and plastics, for a population of approximately 1.4 million.
Without abundant fresh water, atmosphere, soil, and everything else in our biosphere that makes life possible, an off-world colony would need to import more. A lot more.
Grace stated, “Right now, that’s not really feasible.” “I do not believe missiles will ever be practical. The issue then becomes, “How can the cost of placing material in space be driven through the floor?”
SpaceX, led by Elon Musk, is also attempting to address this issue with its super-heavy Starship vehicle, which will be capable of carrying over 250 metric tons to orbit in a disposable configuration. Grace is, however, skeptical that Starship’s economic system will ever be able to completely compete with Longshot’s.
“I anticipate [SpaceX] spending between $5 and $30 billion on Starship before it’s ready to launch,” he said. “They are going to have to recover that money. […] Some of Elon’s more exaggerated statements about the price they will be able to achieve may be true, but only on a 40- or 50-year timescale. They may have to amortize these expenditures over an extended period of time.”
Thus, Longshot would not render Starship obsolete. Longshot’s system would generate an unsuitable quantity of G-forces for the human body, so space travelers would be much better off on a rocket.
Longshot has made remarkable progress with relatively little funding. Since completing a $1.5 million pre-seed round last April with investors including Sam Altman, Draper VC, and SpaceFund and receiving a direct-to-Phase II SBIR from the Air Force Research Laboratory, Longshot has constructed a test accelerator at its headquarters in Oakland, California, and reached speeds of up to Mach 2.2. Grace stated that he expects to demonstrate velocities greater than Mach 5 within a month.
Short-term, Longshot intends to capitalize on the U.S. Department of Defense’s need for hypersonic capability, secure some contracts, and use the resulting revenue to essentially subsidize the development of a really large, really inexpensive space launch system.
Grace stated that on a longer time horizon, the real money will be made not from the launch system but from the expanding demand for Longshot’s space-based services.
“The key to being able to support this is having a system that can do it at an extremely low cost,” he explained. “You need a system that is designed to be as stupid as possible.”
“Make it larger. Don’t make it wiser. That is quite costly.”