15.07.2021
NASA Solar Sail Asteroid Mission Readies for Launch on Artemis I
Illustration of NASA’s NEA Scout with the solar sail deployed as it flies by its asteroid destination.
Sailing on sunlight, NEA Scout will capture images of an asteroid for scientific study.
NASA’s Near-Earth Asteroid Scout is tucked away safely inside the agency’s powerful Space Launch System (SLS) rocket at NASA’s Kennedy Space Center in Florida. The solar sailing CubeSat is one of several secondary payloads hitching a ride on Artemis I, the first integrated flight of the agency’s SLS and the Orion spacecraft.
NEA Scout, a small spacecraft roughly the size of a large shoebox, has been packaged into a dispenser and attached to the adapter ring that connects the SLS rocket and Orion spacecraft. The Artemis I mission will be an uncrewed flight test. It also offers deep space transportation for several CubeSats, enabling opportunities for small spacecraft like NEA Scout to reach the Moon and beyond as part of the Artemisprogram.
“NEA Scout will be America’s first interplanetary mission using solar sail propulsion,” said Les Johnson, principal technology investigator for the mission at NASA’s Marshall Space Flight Center. “There have been several sail tests in Earth orbit, and we are now ready to show we can use this new type of spacecraft propulsion to go new places and perform important science.”
The CubeSat will use stainless steel alloy booms to deploy an aluminum-coated plastic film sail – thinner than a human hair and about the size of a racquetball court. The large-area sail will generate thrust by reflecting sunlight. Energetic particles of sunlight, called photons, bounce off the solar sail to give it a gentle yet constant push. Over time, this constant thrust can accelerate the spacecraft to very high speeds, allowing it to navigate through space and catch up to its target asteroid.
“This type of propulsion is especially useful for small, lightweight spacecraft that cannot carry large amounts of conventional rocket propellant,” Johnson said.
NEA Scout is also a stepping-stone to another recently selectedNASA solar sail mission, Solar Cruiser, which will use a sail 16 times larger when it flies in 2025.
Sailing on sunlight, NEA Scout will begin an approximate two-year journey to fly by a near-Earth asteroid. Once it reaches its destination, the spacecraft will use a science-grade camera to capture images of the asteroid – down to less than four inches (10 centimeters) per pixel – which scientists will then study to further our understanding of these small but important solar system neighbors. High-resolution imaging is made possible thanks to the low-velocity flyby (less than 100 feet, or 30 meters, per second) enabled by the solar sail.
The data obtained will help scientists understand a smaller class of asteroids – those measuring less than 100 meters (330 feet) across – that have never been explored by spacecraft.
“The images gathered by NEA Scout will provide critical information on the asteroid’s physical properties such as orbit, shape, volume, rotation, the dust and debris field surrounding it, plus its surface properties,” said Julie Castillo-Rogez, the mission’s principal science investigator at NASA’s Jet Propulsion Laboratory.
Near-Earth asteroids are also important destinations for exploration, in situ resource utilization, and scientific research. In the past decade, detections of near-Earth asteroids have steadily risen and are expected to grow, offering expanded opportunities as exploration destinations.
“Despite their size, some of these small asteroids could pose a threat to Earth,” Dr. Jim Stott, NEA Scout technology project manager, said. “Understanding their properties could help us develop strategies for reducing the potential damage caused in the event of an impact.”
Scientists will use this data to determine what is required to reduce risk, increase effectiveness, and improve the design and operations of robotic and human space exploration, added Castillo-Rogez.
NEA Scout is developed under NASA’s Advanced Exploration Systems division. The CubeSat is designed and developed by NASA Marshall in Huntsville, Alabama, and JPL in Southern California.
Quelle: NASA
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Update: 21.01.2022
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NASA Solar Sail Mission to Chase Tiny Asteroid After Artemis I Launch
NEA Scout is composed of a small, shoebox-sized CubeSat (top left) and a thin, aluminum-coated solar sail about the size of a racquetball court (bottom left). After the spacecraft launches aboard Artemis I, the sail will use sunlight to propel the CubeSat to a small asteroid (as depicted in an illustration, right).
Credit: NASA
NEA Scout will visit an asteroid estimated to be smaller than a school bus – the smallest asteroid ever to be studied by a spacecraft.
Launching with the Artemis I uncrewed test flight, NASA’s shoebox-size Near-Earth Asteroid Scout will chase down what will become the smallest asteroid ever to be visited by a spacecraft. It will get there by unfurling a solar sail to harness solar radiation for propulsion, making this the agency’s first deep space mission of its kind.
The target is 2020 GE, a near-Earth asteroid (NEA) that is less than 60 feet (18 meters) in size. Asteroids smaller than 330 feet (100 meters) across have never been explored up close before. The spacecraft will use its science camera to get a closer look, measuring the object’s size, shape, rotation, and surface properties while looking for any dust and debris that might surround 2020 GE.
Because the camera has a resolution of less than 4 inches (10 centimeters) per pixel, the mission’s science team will be able to determine whether 2020 GE is solid – like a boulder – or if it’s composed of smaller rocks and dust clumped together like some of its larger asteroid cousins, such as asteroid Bennu.
“Thanks to the discoveries of NEAs by Earth-based observatories, several targets had been identified for NEA Scout, all within the 16-to-100-foot [5-to-30-meter] size range,” said Julie Castillo-Rogez, the mission’s principal science investigator at NASA’s Jet Propulsion Laboratory in Southern California. “2020 GE represents a class of asteroid that we currently know very little about.”
2020 GE was first observed on March 12, 2020, by the University of Arizona’s Catalina Sky Survey as part of its search for near-Earth objects for NASA’s Planetary Defense Coordination Office.
Developed under NASA’s Advanced Exploration Systems Division by Marshall Space Flight Center in Huntsville, Alabama, and JPL, NEA Scout is a science and technology demonstration mission that will enhance the agency’s understanding of small NEAs. Using a six-unit CubeSat form factor, it will ride as one of 10 secondary payloads aboard the powerful Space Launch System (SLS) rocket, which will launch no earlier than March 2022 at NASA’s Kennedy Space Center in Florida. NEA Scout will then be deployed from a dispenser attached to the adapter ring that connects the rocket and Orion spacecraft.
The mission will act as a nimble scout for future human and robotic missions that may utilize asteroid resources – and will gain important planetary defense insights about this class of NEA.
Fully interactive, Eyes on Asteroids uses science data to help visualize asteroid and comet orbits around the Sun. Zoom in to travel along with your favorite spacecraft as it explores these fascinating near-Earth objects.
“Although large asteroids are of most concern from a planetary defense perspective, objects like 2020 GE are far more common and can pose a hazard to our planet, despite their smaller size,” said Castillo-Rogez. The Chelyabinsk meteor was caused by a small asteroid about 65 feet (20 meters) in diameter – it exploded over the Russian city on Feb. 15, 2013, creating a shockwave that broke windows all over the city and injured more than 1,600 people. That was the same class of NEA as 2020 GE.
Low Mass, High Performance
Learning more about asteroid 2020 GE is only part of NEA Scout’s job. It will also demonstrate solar sail technology for deep space encounters. When released from its dispenser after launch, the spacecraft will use stainless steel alloy booms to unfurl a solar sail that will expand from a small package to a sail about the size of a racquetball court, or 925 square feet (86 square meters).
Made from plastic-coated aluminum thinner than a human hair, this lightweight, mirror-like sail will generate thrust by reflecting solar photons – quantum particles of light radiating from the Sun. The sail will provide most of NEA Scout’s propulsion, but small cold-gas thrusters with a limited propellant supply will also assist with maneuvers and orientation.
“The genesis of this project was a question: Can we really use a tiny spacecraft to do deep space missions and produce useful science at a low cost?” said Les Johnson, the mission’s principal technology investigator at Marshall. “This is a huge challenge. For asteroid characterization missions, there’s simply not enough room on a CubeSat for large propulsion systems and the fuel they require.”
Sunlight acts as a constant force, so a tiny spacecraft equipped with a large solar sail can eventually travel many miles per second. Solar sails are a high-performance propulsion system for low-mass and low-volume spacecraft, according to Johnson. NEA Scout will maneuver by tipping and tilting its sail to change the angle of sunlight, altering the amount of thrust and direction of travel, similar to how a boat uses the wind to sail.
In September 2023, asteroid 2020 GE will make a close approach with Earth, and with a gravitational assist from the Moon, NEA Scout will have gathered enough speed to catch up. Mission navigators will fine-tune NEA Scout’s trajectory before the spacecraft approaches within a mile of the asteroid.
“NEA Scout will accomplish probably the slowest flyby of an asteroid ever – at a relative speed of less than 100 feet [30 meters] per second,” said Castillo-Rogez. “This will give us a few hours to gather invaluable science and allow us to see what asteroids of this class look like up close.”
NEA Scout sets the stage for future solar sails: NASA’s Advanced Composite Solar Sail System will demonstrate novel, lightweight booms to deploy a solar sail from a CubeSat following its 2022 launch. After that, Solar Cruiser, an 18,000-square-foot (nearly 1,700-square-meter) solar sail technology demonstration, will use sunlight to travel toward the Sun in 2025, enabling future missions to better monitor space weather.
Quelle: NASA