From the distance, asteroids don't seem much more than a space rock, but NASA has good reasons to rank them as high priority targets. There are currently more than 1.1 million identified and known asteroids. The total count for the solar system is expected to be much higher with new discoveries being made constantly.
Many confuse asteroids, comets, and meteorites or believe they are all the same. Asteroids are rocky objects that vary with strange shapes. Some asteroids even have orbiting “moon asteroids”, and all asteroids orbit the sun. A comet also orbits the sun but is made of ice and dust. A meteorite is a small fragment of an asteroid or a comet, and is called a meteor when it gets close to Earth.
Earth security, science, and space resources are the three main reasons why NASA is interested in asteroids. NASA has two active missions in space on route to asteroids, DART and Lucy. The third mission also heading to an asteroid, called Psyche, will launch in 2022. These missions will help NASA to not only understand how the Earth was formed, but also help the space agency better understand asteroids that could collide with the planet.
Rocky, Life-Giving, Dangerous Treasures
Every day the planet is bombarded with tons of interplanetary material. Most of the incomings are very small and burn up in the atmosphere. Some that are large enough can be seen as falling meteors or meteor showers. A very small percentage of killer-planet asteroids, like the ones that caused the extinction of the dinosaurs, are on a very close collision path to Earth. The NASA DART mission will test how to protect Earth by impacting an asteroid with a spacecraft years or months in advance to slowly correct its trajectory and save the planet.
Asteroids are leftover fragments of when the solar system was forming. The cosmic material that did not accumulate to form planets or moons is still out there untouched for the past 4.5 billion years. The NASA Lucy mission is traveling to the Trojan asteroid near the giant Jupiter to take a close look at asteroids. NASA says it will be like looking at fossils billions of years old that can give humankind clues to the beginning of life.
Asteroids are also estimated to be worth billions of dollars in metals, volatiles, and other materials. NASA's Psyche mission will route to the asteroid Psyche, rich in nickel and iron. The asteroid is believed to be an early planet's inner core that had its outer layers blown off during violent cosmic collisions. The interest in space mining for oxygen, metals, rare elements, hydrogen for rocket fuel, water, helium, and other useful elements is also a rapidly growing trend. Asteroids hold the secret to life, are treasures for science and mining, and have the power to destroy planets and transform solar systems. It's no wonder NASA is dedicating so many resources to studying them.
Source: NASA
