Predicting advanced composites use in launches to the moon, Mars

Like millions of others around the globe, I watched the live Webcast on YouTube of the SpaceX Falcon Heavy launch on Feb. 6 with fixated interest. The rocket was designed with the largest thrust and payload capability since NASA’s Saturn V rocket was retired in 1973 — we were witnessing a moment in history. Although the launch was originally scheduled for early afternoon, high-altitude winds halted the countdown, threatening to postpone the launch by a day. By no means was success guaranteed (it never is with rocket launches). In an interview with one of the US national networks, SpaceX founder and CEO Elon Musk cautiously offered a 50-75% probability that all would go well.

With just minutes to go before the day’s launch window would close, the countdown resumed unabated, and Falcon Heavy left the launchpad, both side boosters disengaged and — spectacularly — returned to touch back down, perfectly upright on Earth-based landing pads, in a fashion that looked more like ballet than rocket science. Meanwhile, the center core continued upward, and delivered its test payload, Musk’s red carbon fiber-bodied Tesla Roadster, into space, headed to an intended orbit of the sun near that of Mars. Despite the center core missing its landing on a drone platform at sea, this first launch was declared a success, paving the way for future, large-cargo missions.

SpaceX has managed this despite launching its first rocket less than 10 years ago. There is no question that Elon Musk is nothing if not unconventional and provocative, as I’ve written briefly about him in this column in January 2016. He’s a definite risk-taker, as evidenced by the number of ventures he has started, most notably Tesla Motors, producer of battery-powered cars, and more recently, heavy trucks. To provide the batteries for its vehicles, as well as its in-home Powerwall storage systems, Tesla built a giant facility, named the Gigafactory, in Nevada, with plans for additional factories. Tesla also has introduced residential shingles that double as solar panels (feeding energy to their home storage systems), and Musk has launched both Hyperloop and The Boring Co. to speed up transportation within and between large cities.

With Falcon Heavy, Musk clearly has set his sights on establishing a colony on Mars, with the Moon as an intermediate base station, and on doing so within the next decade. This goal is supported by the current US administration’s directive to NASA that it move forward with returning humans to the Moon, and eventually, sending humans to Mars. 

SpaceX is not the only rocket company sensing opportunity in this arena. Boeing, Lockheed Martin and Blue Origin, founded by Amazon’s Jeff Bezos, also are working on heavy launch vehicles that are able to deliver big payloads into deep space.

Irrespective of what launch vehicles provide transport for colonization efforts to the Moon or Mars, advanced composites are sure to play an enabling role. Although only the interstages and payload fairing of the Falcon 9 and Falcon Heavy are composites, it is the payloads themselves that these and other rockets will carry that matter most. For decades, satellites, probes and space telescopes have relied on lightweight carbon fiber composites to achieve their missions and allow extra fuel and instruments to be carried aboard.

The strength-to-weight and stiffness-to-weight ratios of carbon fiber composites compared to metals make them essential to effectively setting up bases on the Moon and Mars. Limits on payload capability are defined by the thrust needed to overcome Earth’s gravitational pull. By using lower-density materials like composites, more building materials needed to establish base structures can be sent with each mission. Speaking of gravity, that force on the Moon is only one-sixth that on Earth. On Mars, it’s just over one-third vs. Earth. Although such structures will have the same mass as on Earth, the supported weight, which is proportional to the force of gravity, will be much lower, further enabling lighter structures. Of course, any buildings erected on these distant orbs will need to withstand other environmental forces, such as wind, erosion and impacts. 

Who says everything must be sent to space already fabricated? Common elements, like composite sheets, rods and tubes, which can be packed neatly, make sense to fabricate down here. But such missions offer opportunities for novel composite materials and technologies. Why not send up several 3D printers along with containers of carbon fiber-reinforced polymers, and just fabricate connectors, vehicle components and other items onsite? Surface transportation is most likely to be battery-powered, and lightweight vehicles made of advanced composites produced via 3D printing make perfect sense. Whether such vehicles will look at all like a Tesla Roadster is still anyone’s guess.