This artist’s illustration of Bennu and other asteroids represents building blocks of the rocky planets of our solar system. Photo credit: NASA
Asteroids have orbited the sun in space for thousands of millennia, standing as ancient storytellers and holding clues to the formation of the solar system. NASA‘s first mission to collect a sample from an asteroid, the origins, spectral interpretation, resource identification, security regolith Explorer (OSIRIS-REx) has just made its first attempt at collecting the potentially dangerous asteroid Bennu and brought its secrets to Earth. But NASA also has several other asteroid missions with different purposes as well as a dynamic program that allows us to identify and learn more about potentially dangerous objects in defense of our planet.
Not all asteroids are created equal. However, scientists believe that asteroids similar to Bennu could have colonized Earth with water and organic compounds, and are potentially rich in resources and precious metals that could be valuable to humanity in the future, to the exploration of the solar system by robots and humans to advance. Scientists are also keen to find potentially more dangerous asteroids, learn more about their orbits and physical properties, and develop potential protective measures to mitigate the threats to Earth.
Over the next few years, NASA will launch several ambitious missions to study unique asteroids and fill in more pieces of the cosmic puzzle. The Double Asteroid Redirection Test (DART) and Lucy missions will start in July and October 2021, respectively. The Psyche mission follows closely with the start date 2022. And while New Horizons continues to investigate the Kuiper Belt for its worthwhile fly-bys Pluto and Arrokoth, the newest mission to asteroids, Janus, is under development. OSIRIS-REx is slated to begin its journey back to Earth in 2021 with its return in 2023.
NASA’s Planetary Defense Coordination Office (PDCO) tracks and characterizes potentially dangerous objects and investigates strategies to reduce their danger. The PDCO funds projects as part of its NEO (Near-Earth Object) observation program, which uses various ground- and space-based telescopes to search for NEOs, determine their orbits and measure their physical properties.
“Asteroids and small bodies are important keys to understanding the history of the solar system,” said Lori Glaze, director of NASA’s Planetary Science Division. “The technology and engineering required to visit and study them has improved rapidly, and we are excited about the transformation science our missions to asteroids will bring us in the near future.”
ARROW
DART is PDCO’s exciting first planetary defense mission. The mission will test planetary defense technologies to prevent a dangerous asteroid from impacting Earth. DART will be the first demonstration of the kinetic impactor Technique to change the movement of an asteroid in space. The goal is the binary Didymos asteroid system, which consists of the larger Didymos and its smaller ‘Moonlet’ Dimorphos with diameters of ~ 780 and 160 m respectively. The spaceship will hit Dimorphos in September 2022 with an almost frontal impact that will alter the speed and path of Dimorphos. However, there is no worry that the system’s path will ever cross that of the earth. While scientists are using an international observation campaign with earth-based telescopes to determine the change in the orbit of Dimorphos, NASA’s international partnership with the Italian space agency and its Light Italian Cubesat for Imaging will enable a close-up action of Asteroid (LICIACube), which takes images of Picks up impact effects on the surface and the expected ejecta cloud it will create. The Applied Physics Laboratory at Johns Hopkins University in Laurel, Maryland leads the mission for NASA.
LUCY
The Lucy mission is unlike any other space mission in history. It examines eight asteroids orbiting our sun and offers unprecedented insights into planet formation processes. Lucy will take a 12-year journey to study the diversity of a main belt asteroid and seven Trojan asteroids – asteroids trapped within JupiterOrbit – believed to be remnants of the same material from which the outer planets were formed. The suite of instruments on board Lucy, in addition to the satellites and rings of each asteroid, will characterize the surface geology, surface color and composition, and interior and bulk properties. The name of the mission comes from the fossilized human ancestor (called “Lucy” by those who discovered it), whose skeleton gave researchers a unique understanding of the evolution of mankind. Similarly, the Lucy Mission will change knowledge of our planetary ancestors and the evolution of the solar system. Lucy is led by lead investigator Hal Levison of the Southwest Research Institute in Boulder, Colorado.
PSYCHE
Dancing in orbit between Mars and Jupiter is the unique metal asteroid Psyche 16 – the target for NASA’s Psyche mission. Scientists believe this asteroid could be like the inaccessible metal cores of terrestrial planets. In contrast to other rocky or icy bodies, scientists believe that psyche is composed primarily of metallic iron and nickel – similar to the Earth’s core – and possibly the “heart” of an early planet that has lost its outer layers. The mission’s instruments not only characterize the topography, but also help scientists determine whether Psyche 16 is really the nucleus of a protoplanet or whether it is unmelted material. You will also be able to determine the relative ages of regions of the asteroid’s surface and determine whether small metal bodies contain similar light elements that are expected in the high pressure cores of terrestrial planets. Psyche is led by lead investigator Lindy Elkins-Tanton of Arizona State University.
ASTROBIOLOGY
The O in OSIRIS-REx stands for Origins – understanding the origins of the solar system, including the origin of life on earth. Bennu, the target of the OSIRIS-REx mission, will help us answer important astrobiological questions, such as the role asteroids may have played in providing life-building compounds to Earth. It is a primitive carbonaceous asteroid that documents the earliest history of our solar system. Bennu is rich in carbon and may contain organic molecules such as those that make up life on earth. While we were able to study meteorites, they went through extremely hard re-entry into the earth. The sample collected by OSIRIS-REx remains unchanged, which increases the accuracy of scientific research and results.
Asteroids will continue to be a source of intense scientific curiosity for decades to come as these and other missions explore our numerous and diverse neighbors in space. As we grapple with the challenges of protecting ourselves from these ancient space rocks, we will also learn more about our solar system and how these mysterious objects played a role in our past and will affect our future.
