Podcaster:  Chris Impey

Title: Go Boldly, Go Small

Organization:  University of Arizona

Link :

Description: This week Professor Chris Impey, from the University of Arizona and author of the book: Beyond: Our Future in Space, presents his fourth in a series of five podcasts on human space exploration, beginning with the recent growth in private sector space launches and looking to the future of human spaceflight.

Bio: Chris Impey ( is a University Distinguished Professor and deputy head of the astronomy department at the University of Arizona. His astronomy research focuses on observational cosmology, using telescopes and other instruments to study the large-scale structure and evolution of the universe. He also does research on education and science literacy. Chris is also the the creator of the Teach Astronomy website (, which supports non-science majors, and he is teaching free massive open online classes (MOOC) through Udemy and Coursera with over 40,000 students enrolled. He has taught cosmology to Tibetan monks as the astronomy faculty leader for the Science for Monks program, and is an author of multiple books, the most recent of which is titled: Beyond: Our Future In Space.

Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. We still need sponsors for many days in 2016, so please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this webpage, or contact us at

Space travel is hard.

Lifting humans into Earth orbit requires a large amount of energy to overcome the gravity that keeps us all pinned to the planet. Once there, they’re subject to the disorienting and sometimes debilitating effects of weightlessness. They’re peppered with cosmic rays and harmful ultraviolet radiation. Only a slender metal sheath separates them from the gut-busting vacuum outside.

About 550 people have slipped the bonds of gravity, ten times fewer than the number who have climbed Mount Everest. The club of those who have set foot on another world is even more exclusive: twelve.

It’s easier and safer to let machines do the exploring. Our robotic space probes span the Solar System. Messenger is orbiting Mercury, and New Horizons is fast approaching Pluto. Cassini is inspecting Saturn and its moons, while Rosetta is orbiting a comet, and Dawn is checking out the largest asteroid. Mars currently has four orbiters and the Opportunity and Curiosity rovers trundle around the surface looking for signs of habitability.

These missions are highly complex assemblies of hardware. They cost over a billion dollars each and each took a decade to design and launch. What if getting into space could be easier, cheaper, and quicker?

It can, if we reap the benefits of miniaturization in consumer technology and build miniature satellites.

A CubeSat is the size of the original Rubik’s Cube. It emerged from Bob Twiggs at Stanford University, who was frustrated by the expense and the long lead times of the commercial satellite industry. Twigg came up with an optimum size based on a box used to display Beanie Babies. It’s designed to weigh no more than a kilogram; its modular design means that CubeSats can be combined to perform complex tasks for a small fraction of the cost of a traditional satellite.

CubeSats are booming. After a decade during which less than 100 were launched, the next five years should see over 1000 launched at a typical cost of $100,000 each. That’s low enough that universities and student groups can participate, often using crowd-funding web sites to pay the bills.

Smartphones already contain cameras, accelerometers, GPS receivers, and devices for measuring magnetic fields, and now those capabilities can be deployed in orbit. A crowd-funded project at Cornell University packed all the basic components of a satellite into “sprites” the size of a postage stamp, costing just $25 each.

So far, CubeSats are looking down on the Earth and are in captive orbits, but this will change. Benjamin Longmier did propulsion research at NASA’s Johnson Space Center and founded a company that’s close to producing a miniaturized propulsion system using water or solid iodine as a fuel. Other groups are working on tiny pulsed plasma thrusters. NASA is encouraging this development with a $5 million prize for any group that can prove their technology in deep space.

The best form of propulsion is free. The Planetary Society has raised $4.5 million to build something called LightSail. In their concept, a nanosatellite will unfurl a huge sail made out of Mylar that can harness sunlight to push it out of Earth orbit. The acceleration is modest but the uninterrupted power from a solar sail means the spacecraft could travel throughout the Solar System, or beyond.

Within a decade, tiny spacecraft will ply the Solar System. Their payloads will be hundreds or thousands of motes or units of “smart dust.” Each mote will contain a computer, sensors, a power source, and a wireless antenna, yet will be no bigger than a grain of rice. The military is already using motes for remote sensing of battlefields, and environmental scientists are using them to go where humans can’t venture.

We can imagine legions of these motes floating down to the surface of Titan to test the conditions there, or robotic versions crawling across the surface of Mars to look for life. Research groups with different goals could combine to pay for launch costs. Competition would spur innovation.

As a stretch goal for the space program, consider this. The Kepler mission has shown that there are twenty billion Earth-like, habitable worlds in the Milky Way. The closest may be in the double star system Alpha Centauri, just 4.3 light years from Earth. As proposed by NASA researcher Greg Laughlin, we could send waves of miniaturized spacecraft to the system, powered by solar sails, that would relay information back long the chain. Large numbers would guarantee redundancy. Traveling at 20% of light speed, it would take two generations for the first data to come back. But imagine the excitement as humanity got to see on live TV whether or not there’s life on the nearest Earth-like world.

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365 Days of Astronomy
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