Project Persephone

"Galvanize public interest ..."

SpaceX is a company that started with Elon Musk's dream of a greenhouse on Mars. In that, one of the company's original motivations resembles one of Project Persephone's: to bring life to the barren reaches of space. But as so often with new ventures, there was a pivot. Originally, Musk was going to do it on somebody else's rocket.¹

Put a few plants on Mars, green against red soil -- could it inspire a human mission costing thousands of times more? It seemed worth a try. But how to get it to Mars at all?

This founder-dreamer considered the low-cost leader in interplanetary space launchers: Roskosmos. But he was discouraged: Russian launch brokers started with lower prices but kept raising them.

Musk decided he had to start his own launcher company, in hopes that, even in America, with its higher labor rates, there might be some unexploited technological edge to be gained. Hence: SpaceX. In that, there was another resemblance to Project Persephone's motivations: making access to space cheaper. The company has achieved a major reduction in costs through a combination of launcher design and management structure. The combination is arguably Russian: standardize on one engine, to be used in clusters in the lower stage, and keep almost all design and production under one, highly localized, corporate roof, to enable a more "agile" engineering and production style.

Can a company like Space X make projectile space launch an idea whose time is past?

Projectile launch competitor to Space X? Or enabler of further cost reductions?

There is a complex relationship between projectile space launch and SpaceX's striving toward cheaper launch. Are they competitive? Complementary? It's not impossible that, with high enough launch rates, SpaceX could show such dramatic reductions in launch cost that there's no longer any point in investing in anything much cheaper, especially since projectile launch is limited to naturally G-tolerant and G-hardened payloads. Indeed, when SpaceX finally launched about 4 times cheaper than the next-cheapest American launcher, John Hunter of Quicklaunch, which had proposed to put fuel supplies into orbit with a light gas gun system, seemed to give up on the whole idea. If SpaceX achieved some reusability (and it was always Elon Musk's goal to reach 100% reuse) then $1000/kg with Quicklaunch wouldn't be competitive. And it seemed likely that SpaceX would eventually reach that goal.

First stage return - only 35% cheaper?

Upper stage return was repeatedly demonstrated, to some exultation in the aerospace community, except perhaps where it sparked fear among competitors. However, Gwynne Shotwell, the chief executive of SpaceX, assessed lower stage return as a clear engineering success but as only a qualified success in business terms: the end-to-end cost savings of first-stage return could be as low as 35%. Returning an upper stage seemed possible, using the extra fuel margin possible with Falcon Heavy. But it wasn't necessarily a bargain. Investing in lower-stage return had also cost SpaceX a lot, and that investment had to pay dividends somehow.

John Hunter has since started yet another light gas gun launcher company (his fourth, after Jules Verne Gun, Teklaunch, and Quicklaunch), called Green Launch. His hypothetical customer for Quicklaunch would have been a humans-to-Mars mission, since the fuel requirements for getting a significant mission to the surface and back to Earth would be truly enormous. This new startup could have a more practical purpose: launching fuel to orbit to help return upper stages to Earth, intact, to be reused, for the satellite launch industry. The company that seemed to encourage, then kill, Hunter's chances will perhaps finally breathe new life into the idea.

Light gas guns are only one technology that's been proposed to shoot things into space at near orbital velocity. There are perhaps half a dozen more basic ideas. Elon Musk has a bigger dream, for which the Martian greenhouse was to be only a kind of PR bootstrap, or igniter of political will. It is to make Mars a second planetary home for humanity. There's not much to be said for certain about that goal, except that it will require launching a lot of non-human mass to low Earth orbit. For as long as SpaceX remains stalled at diminishing returns to effort in its attempts to make space access truly cheap, the projectile space launch option can't be foreclosed.

¹ Here's The Wacky Reason Elon Musk Founded SpaceX, Ajai Raj, Business Insider, Oct. 14, 2014 ⇑