4 CHAPTER 1 What is the Solar Sistem A solar system is a star and the A galaxy is a clump of billions of solar objects that travel around it systems Our Solar System is in the including planets asteroids and Milky Way galaxy This is a spiral-shaped comets Our Solar System centers on spiral-shaped galaxy that contains several the Sun The Sun's gravity a force that hundred billion stars including our attracts objects holds Earth and other Sun The Milky Way is about 100,000 planets and objects in orbit around it light years across A light year is the Some planets are orbited by moons distance light travels in a year which is Mercury is the closest planet to the around 5 9 trillion miles 9 5 trillion km Sun One of the most distant objects is On a dark night you can sometimes see Sedna It is not classified as a planet the Milky Way as a thick band of stars It is one of the many objects in the in the sky Our Solar System is in one of outer reaches of our Solar System the galaxy's four spiral arms Neptune Uranus Saturn Jupiter Mars Earth Venus Mercury This artwork shows the order of the planets in our Solar System in relation to the Sun
In a galaxy such as the Milky Way stars and their solar systems are bunched in long arms that form a flat spiral shape Many stars have planets circling around them There could be billions of other planets in the Milky Way alone Some solar systems possess more than one star Binary star systems have two stars Multi-star systems have three or more stars in one solar system Chasing Space In the United States the National Aeronautics and Space Administration NASA improves our understanding of the Solar System by exploring the planets their moons and small bodies such as comets Its research seeks to learn about the origin or beginning and history of our Solar System NASA scientists are also looking out for the possibility that life exists elsewhere in space The 2018 Global Exploration Roadmap is a document that shows the plan of 14 space agencies that have come together with a common goal to expand human presence in our Solar System The plan starts with missions to the International Space Station ISS which orbits Earth then advances to the Moon and then to Mars Cooperation between the agencies will be the key to success 5
Hayabusa2’s mission has been to study Ryugu and to also carry four separate landers to investigate the comet’s surface Why Explore Our Solar System is made up of the Sun eight planets and their moons at least five dwarf planets millions of asteroids and probably billions of comets Despite knowing all this about our Solar System however there are still many unanswered questions There is a lot to discover Human and robotic exploration will help find answers Learning More The Japanese Hayabusa2 spacecraft arrived at the asteroid Ryugu on June 27 2018 A few months later it sent a lander to collect samples from the asteroid After Hayabusa2 left the asteroid it began to travel back to Earth When it arrives scientists will study the samples the spacecraft collected These samples may help them understand how asteroids formed in the early years of our Solar System Research such as this expands our understanding of our Solar System Focus of Innovation Space exploration also helps drive new ideas on Earth Some of the technology developed to build the spacecraft and have it land on an asteroid will filter down to have an impact on different aspects of everyday life 6
MISSION Space Science NASA’s OSIRIS-REx was launched in September 2016 to land on an asteroid named Bennu just over two years later Bennu is a small asteroid measuring 1,600 feet 488 m in diameter It was selected as a target from more than 500,000 known asteroids because it is close to Earth Its ancient rocks may hold clues to the origin of life Its surface of loose soil dust and broken rock should be easy for a lander to collect OSIRIS-REx returned its first images of Bennu in August 2018 when it was still 1 4 million miles 2 2 million km away Its influence could include anything from new materials for the transportation industry to communications systems and advances in computer technology New Partnerships The challenges of exploring space are driving new partnerships between governments industries universities and research centers around the world Hayabusa2’s lander MASCOT is operated by the German Aerospace Center DLR and the French Space Agency FSA The agencies consulted 100 international and national partners before choosing a final landing site on Ryugu This artwork imagines asteroids surrounding a young planet when our Solar System was new 7
