Sailing to an Asteroid on the Light of the Sun

Episode Summary

Executive Summary: The episode centers on NASA’s NEA Scout solar sail mission, a 6U CubeSat on the first Space Launch System flight, and how it compares with the Planetary Society’s LightSail 2. Les Johnson explains the sail’s asteroid flyby objectives, deployment mechanics, operational challenges, and broader solar-sail future, while Bruce Betts adds skywatching, mission history, and a trivia contest. Emily Lakdawalla also reports on BepiColombo’s launch and imagery.

Main Topics: NEA Scout mission overview: Les Johnson describes NEA Scout as NASA’s first interplanetary solar sail and first sail mission required to accomplish science, not just demonstrate technology. It will travel to near-Earth asteroid 1991 VG for a close reconnaissance flyby. Solar sail engineering and deployment: The conversation details the sail’s 86-square-meter area, its four 21-foot booms, the tension-driven deployment method, and the use of party balloons during testing to prevent the booms from dragging under Earth gravity. Comparison with LightSail 2 and shared heritage: Johnson explains that NEA Scout and LightSail 2 differ in sail geometry and spacecraft design but share technology lineage from NanoSail-D and benefit from close collaboration between NASA Marshall and the Planetary Society. Mission operations and trajectory control: The team must continuously balance thrust, power, and communications, reorienting the sail throughout the mission. The spacecraft will use autonomous operations after initial intensive control periods and a cold gas thruster for launch safety and attitude control. Future applications of solar sailing: Johnson outlines potential uses for solar sails in advanced solar storm warning, solar polar science, low-cost asteroid reconnaissance, and eventual interstellar beamed-energy sailing. BepiColombo launch and planetary reporting: Emily Lakdawalla discusses ESA/JAXA’s BepiColombo mission, its successful launch, solar panel deployment confirmation, complicated Mercury-bound trajectory, and an infrared launch video captured by a mission scientist. Bruce Betts segment: skywatching, history, and trivia: Betts covers evening sky targets, Mars Odyssey’s 17-year anniversary, the naming origin of BepiColombo, and a primorial-based trivia contest centered on the BepiColombo mission sequence.

Key Arguments: NEA Scout is NASA’s first interplanetary solar sail and must perform science, not merely a technology demo. Solar sails provide continuous low-thrust propulsion without running out of propellant, enabling mission flexibility and possible return flybys. The spacecraft’s tiny 6U form factor severely constrains payloads, so the mission carries only a camera plus flight systems. Deployment is technically difficult because large booms store high strain energy; controlled, slow extension is required to avoid damage. NEA Scout and LightSail 2 have different sail architectures but represent related steps in a shared solar-sail development path. A cold gas thruster is required both for lunar-avoidance safety after SLS deployment and for attitude-momentum management during flight. Solar sails may be especially valuable for solar storm warning missions, high-latitude solar observations, and low-cost asteroid reconnaissance. Beamed-energy sails and metamaterial-based sails are promising future directions, though material and engineering challenges remain. BepiColombo’s successful launch and solar panel deployment were validated with onboard cameras and highlighted by an infrared launch recording. Public enthusiasm, educational outreach, and collaboration across agencies and institutions are presented as essential to advancing spaceflight technology.

Data Points: NEA Scout sail area: 86 square meters - Les Johnson describes the size of the sail compared to a school bus-sized area Sail boom length: Over 21 feet long - Each of the four booms used to deploy the sail Spacecraft form factor: 6U CubeSat - NEA Scout must fit as a fully functional interplanetary spacecraft in a very small CubeSat package Asteroid target: 1991 VG - Near-Earth asteroid selected for NEA Scout’s flyby reconnaissance Closest flyby distance: About half a kilometer - Planned close approach for imaging the asteroid Cruise duration: About 2 to 2.5 years - Estimated travel time to the target depending on launch timing Launch vehicle ride: Space Launch System (SLS) - NEA Scout flies as a secondary payload on the first SLS mission Number of CubeSats on SLS upper stage: 13 - Johnson says there are 13 6U CubeSats riding along BepiColombo trajectory duration: Seven years - Emily notes the mission’s long trajectory to Mercury Mercury flyby/orbit sequence: Earth, Venus twice, Mercury five or six times - Complex gravity-assist trajectory described in the BepiColombo discussion Mars Odyssey age: 17 years - Bruce Betts cites Mars Odyssey’s anniversary in this week in space history Trivia contest answer: Saturn 1B - The rocket that launched Apollo 7 was identified by a winning listener Interstellar sail concept: One meter wide sails - Bruce references Breakthrough Starshot’s extremely small sail concept Material strength reference: 300 times stronger than steel by weight - Description of graphene during Johnson’s discussion of advanced materials

Pivotal Quotes: "The Near-Earth Asteroid Scout is going to be the U.S.'s first interplanetary solar sail, and it'll be the first mission that NASA will have flown with a sail that actually has to go achieve science." — Les Johnson: Mission definition and significance of NEA Scout "With a solar sail, you really can't stop. The sun's always shining." — Les Johnson: Explaining continuous low-thrust propulsion and why the mission is a flyby rather than a stopover "What if when the light hits the sail, instead of reflecting off according to the laws of just standard optics, you can direct that light to emit from the sail in whatever direction you want?" — Les Johnson: Discussion of metamaterials and future sail control possibilities

Implications: Solar sails are moving from demos to real science missions. NEA Scout may prove low-cost deep-space reconnaissance and help pave the way for future solar, asteroid, and even interstellar missions.