Space probes

Space is a dangerous place to explore. There is strong cosmic radiation, asteroids and debris can destroy spacecraft, there is no water, and no air to breathe. Space is so large, that even reaching the planets closest to Earth takes months, or years! All this makes travelling to other planets quite impossible for humans for now. Yet, we can still reach other planets, moons or asteroids to collect information about them.

How? Scientists and engineers construct robotic devices that can travel into space and operate on their own, without any people on board. Equipped with a set of tools and scientific instruments, these devices collect data and take pictures. This information is then sent back to Earth, usually by radio, so scientists can analyse it and use it in their research. Such devices are known as space probes.

The purpose of different space probes varies, and each probe is usually designed with a specific mission in mind. We can divide space probes into different groups based on how and where they collect information. Some space probes travel through interplanetary space and fly by other planets, often visiting more than one. These are called interplanetary space probes. Maybe you've heard of Voyager 1 and Voyager 2, two interplanetary space probes, sent out into space in 1977.

Their primary mission was to fly by Jupiter and Saturn, study Saturn's rings, and the larger moons of the two planets. However, as the mission went on, the Voyager space probes managed to carry out close flybys of the two furthest planets in our Solar system, Uranus and Neptune. Thanks to the Voyager space probes, we were able to discover new moons and rings of those planets, and even observe active volcanoes on one of Jupiter’s moons. The probes also collected information about magnetic fields and solar winds. Today, nearly forty years since their launch, the mission continues.

In 2012, Voyager 1 entered interstellar space outside of our solar system, followed by Voyager 2 in 2018. Both probes are still sending information back to Earth. Another type of space probe is normally placed in the orbit of an astronomical object, such as a planet or a moon. Going around for several months or years, such probes can collect information about the magnetic or gravitational field of a planet, take pictures of its entire surface, as well as observe any changes that occur while the probe stays in orbit. Such space probes are called orbiters.

An early example of an orbiter space probe was Mariner 9 launched in 1971. It was the first spacecraft to orbit another planet. By the end of its mission, Mariner 9 had measured the composition and structure of the Martian atmosphere and sent thousands of pictures of Mars’ surface back to Earth. There are also space probes that actually land on the surface of astronomical objects. These are called landers or impactors.

Landers are only able to explore astronomical objects that have hard surfaces - such as rocky planets. Scientists have used landers to explore Venus, Mars, Mercury, some moons, and several asteroids and comets. Landers often carry robotic space probes that can move and drive on the surface of the planet — rovers. A well-known example of a rover is Curiosity that has been exploring the surface of Mars since 2012. It’s investigating the Martian climate, geology, and radiation levels, as well as searching for signs of water or potential life.

Even though we can’t really explore other planets ourselves just yet, thanks to space probes, we can study space and learn about our universe from right here on Earth!