NASA’s First Solar Sail Will Hitch a Ride on Artemis I
There is a tiny asteroid in our solar system known simply as 2020 GE. Astronomers discovered it in 2020, but it’s spent billions of lonely years drifting through space. It’s about to get some company, though. NASA has announced that its Artemis I lunar mission will include a small cubesat called the Near-Earth Asteroid Scout (NEA Scout). After hitching a ride on NASA’s new mega-rocket, NEA Scout will use a first-of-its-kind solar sail to visit 2020 GE.
Artemis 1 is currently slated for March 2022, but it might slip later as NASA struggles to get the Space Launch System ready. This rocket will eventually carry astronauts to the moon for the first time in 50 years, but it will also be able to launch numerous secondary payloads with each launch. There will be 10 of them on Artemis 1, which is an uncrewed flight around the moon and back. After the Orion capsule detaches for its lunar voyage, the NEA Scout will be released to begin its trip out to see 2020 GE.
This space rock is far from unique — it’s not even very large at just 60 feet across. That’s what makes it worth checking out, though. We have never studied an asteroid smaller than 100 meters (330 feet) up close. We don’t know much of anything about these minor asteroids because they’re impossible to observe with any reasonable amount of detail from Earth. However, they can still be dangerous if they hit Earth at the right angle. The Chelyabinsk meteor that exploded over Russia in 2013 was even smaller than 2020 GE.
Thus, NEA Scout will use its small cold-gas thrusters to set course for 2020 GE, but it’s the solar sail that will do the heavy lifting. NASA has toyed with solar sails in the past, but this is the first official agency mission to use one. A solar sail generates thrust from the force of solar wind, allowing for very efficient propulsion. The drawback: solar sails are huge. The shoebox-sized NEA Scout will be 925 square feet (86 square meters) when fully deployed, which is about half of a tennis court.
It’s going to take two years for NEA Scout to reach its target, following a 2023 gravity assist from the moon. At that point, it will be able to rendezvous with the asteroid and gather data with its limited suite of instruments. A successful showing for NEA Scout could help the agency prepare for additional solar sail designs like the Advanced Composite Solar Sail System, scheduled for a demo flight in 2022. The Solar Cruiser will test an 18,000-square-foot (nearly 1,700-square-meter) solar sail when it launches in 2025.