Carl Sagan’s wisdom and vision, and how far we’ve come since his time

Even Carl Sagan may never have dreamed that habitable exoplanets could be so abundant. Sagan speculated that other stars may have planets in orbit around them, but he passed away in 1996 just as the era of exoplanet discovery began. He never got to learn just how abundant exoplanets are. Scientists recently combined data from NASA’s Kepler space telescope and the European Space Agency’s Gaia mission to estimate there could be 300 million habitable planets in our own galaxy. The new estimate takes into account star temperatures and the frequency of rocky worlds that could host liquid water on their surfaces. Pictured: An illustration representing the legacy of NASA's Kepler space telescope, the mission that expanded our awareness of the abundance of exoplanets. Image credit: NASA/Ames Research Center/W. Stenzel/D. Rutter.

The European Space Agency’s Philae comet lander tumbled through ancient ice in 2014 that was “fluffi­er than cap­puc­ci­no froth.” The conclusion comes from a new reconstruction of Philae’s path as it bounced across comet 67P before coming to a rest in a dark crevice. The fluffy ice likely dates back to the dawn of our solar system and could be easily sampled by a future space mission. Learn why we study asteroids, comets, and other small worlds.

NASA has released additional images and video from the OSIRIS-REx spacecraft’s historic sample collection on asteroid Bennu on 20 October. The mission has yielded some fresh science, too: A new study predicts Bennu probably began its life in the main asteroid belt before gravity from other worlds nudged it closer to Earth 1.75 million years ago.

A new video shows how the orbits of our solar system’s giant planets may have changed since their births. Jupiter, Saturn, Uranus, and Neptune are all thought to have been born closer to the Sun and then moved, according to the Nice model, named after the city in France where it was developed. New research by Matt Clement at the Carnegie Institution for Science provides a more detailed explanation of what may have happened, as shown in the video.

What does the future hold for asteroid mining? At least two ambitious, smart asteroid mining companies have gone bust. On this week’s Planetary Radio TransAstra Corporation’s Joel Sercel makes the case that his company’s new effort comes at a much better time, and with a better approach. Pictured: The TransAstra Mini Bee is a technology demonstrator of the company's much larger Honey Bee spacecraft. It may be tested in space as soon as 2023. Image credit: TransAstra Corporation.

How have presidents affected space exploration? Join Planetary Society board member and George Washington University Space Policy Institute professor emeritus John Logsdon on 10 November in a free webinar, ‘Presidential Leadership in Human Space Exploration Yesterday and Today.’ Logsdon will explore the impact of past U.S. presidents on human space exploration, and will speculate on the future of human spaceflight under the next administration.

Administrations change; our space policy priorities don’t. As we finalize the content of this newsletter, a highly contentious U.S. presidential election is being decided. The Planetary Society is a nonpartisan organization committed to working with a presidential administration of either party to advance space science and exploration. Regardless of the outcome, our space policy priorities remain the same.