In a certain sense, it’s easy to keep things in orbit around Earth. However, it’s hard to keep satellites in a specific orbit, which is what matters most for communicating with them and they with us, whatever task they’re designed to perform. Thanks to the work of rocket engineer Yvonne Brill in the early 1970s, the process is remarkably automatic.

Brill’s design eliminated this redundancy and lightened the spacecraft in the process. She also used a type of fuel called hydrazine, which is so reactive you don’t need oxygen or another chemical injection to ignite it. (On Earth, we’ve got lots of oxygen available for making things burn, but in space, you need to carry your own fuel for fire.) Brill’s system pumped liquid hydrazine through an aluminum nozzle. The chemical composition of the nozzle reacted with it, splitting it into smaller molecules and releasing a lot of energy. [Read more…]

I’m no rocket scientist, but I can appreciate the challenges of engineering something that needs to stay in the same orbit for years or decades. Yet the New York Times obituary for Brill mentioned her remarkable achievements as a sort of afterthought, as though they weren’t very important, really, in the scheme of things. My piece isn’t an obituary—I mostly write explanatory pieces about science, after all—but Brill’s contribution to spaceflight in general and the communications satellite revolution of the 1980s is astounding.

Yvonne Brill and the technology keeping satellites in orbit

The business end of a Rocketdyne F-1 rocket engine, used in the first stage of the Saturn V rockets. Five of these engines were used to launch the Apollo missions into space. Note the picnic tables at left for scale comparison.

For the next two weeks, I am on the move, traveling to various observatories in the American south and southwest, as part of the research for my book-in-progress Back Roads, Dark Skies: A Cosmological Journey. This morning, I will be visiting the Laser Interferometer Gravitational-wave Observatory (LIGO) near Livingston, Louisiana, before heading west to other observatories in Texas, New Mexico, and Arizona. My full itinerary is over at Galileo’s Pendulum:

Being a travel book, though, I am also seeking a new way to see through travel and exploration. Cosmology is a very familiar field to me, but often the person closest to a subject is the worst to try to explain it to a lay audience. By going to particle physics labs and astronomical observatories, I am learning to see my own discipline in a new way, in hopes that it will help me bring it to my readers. As you can tell, this book is different from most cosmology books (A Brief History of Time is perhaps the best example), where the focus is on highly speculative ideas and Big Theories. While theory will always inform the research I discuss—and, being a theorist myself, I can’t help but discuss theory—the primary emphasis of Back Roads, Dark Skies is on experiment and observation. Without these things, theory is nothing but the ramblings of creative people, unconnected to reality. [Read more…]

While the scientific part of the agenda begins today, I haven’t been idly driving without keeping an eye out for interesting things. To wit: yesterday, I saw a wild alligator and one of the engines from the Saturn V rockets, which were used to launch the Apollo missions and the Skylab space station.

The Bowler Hat is on the move