7/5/16 Show feat. Charles Swanson on compact fusion and SpaceX plus Juno on Jupiter/space balloons


Featured Image: A SpaceX Falcon 9 launches from Cape Canaveral, FL, carrying a capsule full of cargo to the International Space Station in April 2015.

We were lucky enough to have a show full of space this week, covering all sorts of travel outside our atmosphere: NASA’s Juno orbiter just reached Jupiter last night, and long-duration atmospheric balloons are almost ready to launch regularly from New Zealand. But best of all, we had Charles Swanson, current PhD candidate in Plasma Physics at Princeton and former employee of SpaceX, tell us about space travel and his views on fusion energy.

Charles had always been looking to space, and he paid attention when Elon Musk’s revolutionary rocket venture SpaceX began in 2002. He earned an internship at the company in 2012, where he worked firsthand on the difficult mission of landing a rocket on the ground. To make spaceflight an everyday venture, we need to be recycling our vehicles: imagine if every airplane flight ended in a crash landing and we had to live with one-time-use 747s! But firing things into space requires immense speeds, so it’s very difficult to have rockets survive both the ascent into orbit and the return down to our planet.

In the end, SpaceX had to engineer its rockets to withstand the brutal vibrations of a

SpaceX’s Falcon 9 rocket under construction. Courtesy NASA.

launch alongside the destructive environments of high atmosphere and outer space. Alongside working on the reusable Dragon capsule, Charles played a crucial role in this endeavor: he tested the self-destruction button for the rocket. In a way, this is the most important part, since making a mistake with the landing is far worse than never landing at all. Of course, engineering a self-destruction button is a big task. The button must never be pressed accidentally (even by shaking during an ascent into space), but if you do press it, the button had better work. Charles’s experience speaks to the true difficulty of designing anything for space: it will have to endure nature at its most severe.

On the whole, Charles is optimistic about the future of spaceflight. He sees the present day as an age where launching rockets is open to companies, not just governments. And this could blow open the space industry–we’ll see a lot more tech development in the field over the next decades, and who knows what possibilities might lie in that direction for consumers and scientists. Charles had a lot to say about Musk’s influence on the company: his decisions happened on every level, from budgeting and big-picture plans to engineering the minutiae of engine wiring.

A cartoon of a tokamak, courtesy of EUROfusion.

After the internship at SpaceX, Charles did the only natural thing and began pursuing a PhD in Plasma Physics at Princeton. In his role as a researcher, Charles studies a special time of fusion reactor (a topic we’ve covered before on this show). But today, the leading choice for making fusion happen is big and costly: the tokamak contains a plasma very well, even if its structure takes years to build. An alternative reactor type that  keeps fusion power cheap and small is the FRC (Field Reversed Configuration).

The FRC’s versatile, simpler design comes from using the plasma itself to act as a magnet. A plasma is just a charged gas, and Charles’s group creates currents in the plasma that help to confine itself. Therefore, the whole system saves on magnet costs and can be much smaller: think small enough to fit on a spaceship or in your garage. An exciting future use for these machines might just be as fusion rockets, which could thrust a rocket across the galaxy using fusion power.

An older version of the Princeton FRC which used to sit in Sam Cohen’s lab. It has since been upgraded, but the machine still fits on a tabletop.

Before and after Charles talked with us, we got to some massive news for space explorers. Our show was timely enough to happen the very day that Juno arrived at Jupiter–and this is years in the making! The spacecraft Juno lifted off from Cape Canaveral here on Earth in


2011, then took two years to circle the sun before arriving back near Earth for a gravitational assist.  Now, three years later, it finally reached the Giant Planet. What we know about Jupiter came from Galileo, a craft launched in 1989: it surveyed the many moons, and gave glimpses into Jupiter’s formation. We’ve had to wait until now for our newest technology, which is capable of seeing through Jupiter’s clouds, to learn more about the giant’s inner makeup. Give it a few years, and we may learn more about how the Solar System formed from its observations.

Stevie closed the show with a final way to travel to space–well, near Earth space, but still far above our atmosphere. Ballooning already gives scientists a great option for seeing the sky without interference from the turbulent air above us. Instead of sending a telescope into space with a rocket, letting it float up on a huge balloon is less violent for the instrument and saves us money. We have places like McMurdo in Antarctica that do this regularly (that’s where Stevie’s SPIDER telescope launched), but having a new path in the sky would let us have longer trips. To this end, NASA wants to build a New Zealand balloon base, capable of sending off long-lasting aircraft–and it’s working on the Super Pressure Balloon to help. The researchers just set a new record for balloon flight, and Stevie is optimistic about where this is headed. Stay tuned for more ways into space and more telescopes scouring the sky!

As always, the playlist is at WPRB.com or below.




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