The worlds smallest space probe is called Sprite. It is the size of a Saltine cracker. It is 400 miles (644 kilometers) above us, orbiting Earth.
Countries all around the world have sent Explorer 1 into orbit. All of these early probes studied Earth from space.
Explorer 1s mission ended on May 23, 1958. It returned to Earth in 1970.
SPACE FACT:
NASA stands for the National Aeronautics and Space Administration. Its headquarters is in Washington, D.C.
A PROBES JOB
As technology advanced, scientists sent probes farther into space to study other planets, moons, and .
Today there are three kinds of space probesinterplanetary probes, orbiters, and landers. Some probes have powerful telescopes to study far-away stars and planets. Some fly around in space, while others orbit one object. Still others land on planets and conduct experiments.
Space probes must be able to withstand extreme environments and function properly for long periods of time. Not all probes are successful. Some crash into the object theyre supposed to land on. Some simply dont work. But scientists learn from these mistakes. They continue to make better spacecraft for the future.
An orbiter probe travels around Earth.
CHAPTER THREE
INTERPLANETARY PROBES
Interplanetary probes fly past objects in space. These objects can be planets, moons, stars, asteroids, or objects we havent discovered yet. As it flies by, the probe captures images. It also gathers information about the material the object is made of, as well as the objects shape, size, and .
One of the most exciting interplanetary probes in space today is Neptune. It contains space rocks and other icy objects.
The New Horizons probe collected information from Pluto.
Scientists want to know what kind of material is in the Kuiper Belt. Theyve made educated guesses but they dont know for sure. Scientists also want to study the rocks that float nearby. One of those space rocks is called Ultima Thule.
SPACE FACT:
Ultima Thule is 1 billion miles (1.6 billion km) past Pluto.
On January 1, 2019, New Horizons made contact with Earth, confirming it had flown by Ultima Thule. This is the farthest that any probe has traveled to explore a planetary body. When New Horizons sent images back to Earth, scientists saw the first pictures of this faraway space rock.
The Madrid Deep Space communication complex is part of NASAs Deep Space Network.
SPACE FACT:
New Horizonss radio message was picked up by NASAs Deep Space Network antenna in Madrid, Spain.
CHAPTER FOUR
ORBITERS
Orbiter probes are designed to collect data from a certain planet or moon. Orbiters travel around their object, take pictures, and send the information back to scientists on Earth.
The Hubble Space Telescope is an orbiter. It is the size of a school bus and weighs as much as two elephants. The Hubble has been orbiting Earth for almost 30 years, taking pictures of distant stars and objects in deep space. Soon its mission will end.
A new space telescope will begin its mission in 2021. The . Hopefully it will send back pictures of objects that weve never seen before.
the Hubble Space Telescope in 2002
Other orbiters have been studying planets in our Saturn in 2004. It was the biggest and most expensive probe ever launched.
Cassini studied Saturn and its icy moons for more than 10 years. It traveled 4.9 billion miles (7.9 billion km) and orbited Saturn 294 times.
The Japanese probe Akatsuki began orbiting the planet Venus in 2015. Earth and Venus are often called twin planets. They are about the same size. They were also formed around the same time. But the planets are very different. The surface of Venus is too hot for humans to survive. Earths atmosphere has oxygen, which humans need to live. Akatsuki is studying Venus atmosphere, which is mostly carbon dioxide. It also has clouds made of sulfuric acid, a dangerous chemical for humans.
The Akatsuki probe studied the thick clouds that cover Venus.
In 2013 India became the fourth country to successfully send a probe to Mars. Its probe is called Mars Orbiter Mission, or Mangalyaan. Using this probe, scientists are studying Marss atmosphere and surface. India hopes to have more missions to Mars. One day it may send astronauts to explore the planet.
The Mangalyaan probe has been orbiting Mars since September 24, 2014.
SPACE FACT:
Mangalyaan means Mars craft in Sanskrit. Sanskrit is an ancient Indian language.
Scientists study the sun and how it affects planets. Earth is 93 million miles (149 million km) away from the sun. Getting closer to the suns surface will help scientists learn more about it. On November 4, 2018, the Parker Solar Probe got closer to the sun than any other human-made object before it. By 2024 the probe will be even closer3.83 million miles (6.2 million km) away.