Above Image: The face of the planet Mars © Public Domain
Destination Mars: Journey to Another Planet
Mars is visible in the night sky without the help of a telescope, so it has fascinated people for thousands of years. We have learned a lot about the conditions on Mars by using powerful telescopes, sending robotic orbiters to study the planet from space, and placing landers and robotic rovers on the Martian surface. The next big step is a human mission to Mars.
Why Go to Mars?
Mars is a cold, dry planet with a suffocating atmosphere containing 96% carbon dioxide and almost no oxygen. But Mars has many features that are similar to Earth, such as polar ice caps, seasons, clouds, and a rocky surface with canyons and mountains (see Earth and Mars: Comparison of Planetary Neighbours Backgrounder).
Billions of years ago, Mars may have been more like Earth, with warmer temperatures and abundant liquid water. This makes Mars the most likely planet in our solar system, other than Earth, to have supported the evolution of life. Finding signs of past life is a big goal of missions to Mars. Scientists believe that Martian life was probably microbes, like bacteria. It is exciting to wonder if Martian microbes could still be living in protected areas. Even if life is never found outside Earth, exploring other planets satisfies human curiosity about our place in space.
Learning more about the Martian climate and geology, and how they have changed over time, are additional goals of Mars missions. This data will help scientists figure out if Mars was habitable in the past, and if it can be habitable for humans in the future.
Amazing Robotic Missions
Since the 1960s, NASA (National Aeronautics and Space Administration of the United States) has launched many successful robotic missions to Mars. The earliest missions sent spacecraft on a planetary "fly-by". Then, orbiters were sent to study Mars from a stable orbit (like a satellite), and eventually landers reached the Martian surface (See Figure 1).
Right now, NASA has three orbiters studying Mars from space and two rovers on the planet's surface. The rovers, called Opportunity and Curiosity, are investigating Martian geology, looking for liquid water, and searching for signs of life in soil and rocks (See Figure 2). There are also several inactive landers and rovers from past Mars missions still on the planet's surface.
In 2018, NASA plans to launch its InSight lander mission to explore under the surface of Mars to learn how rocky planets, like Earth, are formed and changed over time. The Mars 2020 Rover is scheduled for launch two years later. It will continue to search for life and gather data that will help future astronauts survive on Mars.
In March 2016, the European Space Agency and Russian Federal Space Agency (Roscosmos) jointly launched the first phase of the robotic ExoMars mission. Its main purpose is to look for signs of life on Mars, by studying atmospheric gases and exploring the surface. The Indian Space Research Organisation has had its Martian Orbiter Mission studying the Martian atmosphere and surface from space since September 2014.
SpaceX, a private American aerospace company, plans to land a spacecraft on Mars in 2018, with technical support from NASA. SpaceX's Dragon capsule, launched by the Falcon 9 rocket, has been delivering supplies to the International Space Station since 2012. More powerful versions of the capsule and the rocket, called Dragon 2 and Falcon Heavy, will be used for the Martian mission.
The Challenge of Getting People to Mars
Mars is our closest planetary neighbour but it is still very far away. The distance between Earth and Mars is constantly changing due to their orbits around the Sun. The closest Mars gets to Earth is around 56 million kilometres. It would take 64 years of non-stop driving to travel this distance at a highway speed of 100 km/h. With current space technology, robotic missions take about 8 months to reach Mars.
To send people and supplies to Mars, NASA is developing the most powerful rocket ever made. The Space Launch System (SLS) will launch up to four astronauts in a spacecraft called Orion (See Figure 3). Before going all the way to Mars, the SLS will be tested during a mission to Earth's moon, which is 386,000 kilometres away. In the 2020s, NASA plans to capture a piece of an asteroid and pull it into orbit around the moon. The SLS will send astronauts aboard Orion to explore the captured asteroid and test new technologies that will be needed for the journey to Mars. This asteroid capture is a controversial mission, so it may not happen as planned. The crewed mission to Mars is planned for the 2030s, so the first humans to set foot on Mars could be today's elementary students.
The Challenge of Living on Mars
So far, NASA has no plans for establishing a permanent settlement on Mars. But even for a mission with a short stay on the surface, keeping astronauts healthy during the voyage will be challenging. The International Space Station (ISS) is in low Earth orbit, 350 kilometres above the surface, and has been continuously occupied since November 2000. Keeping astronauts healthy on the ISS has really been the first step in getting to Mars.
Research aboard the ISS is helping scientists figure out what kind of exercise is best for astronauts, how their immune system and vision are affected by long space missions, how to protect them from cosmic radiation, what kind of food is best to send from Earth and how fresh fruits and vegetables can be grown in a spacecraft. Just as important is learning how to ensure good mental health for astronauts living in a small space for a long time with just a few other people.
On the journey to Mars, the further astronauts get from Earth, the more challenging communication becomes. Two-way communication between Earth and Mars takes about 20 minutes. That is a long time to wait for an answer from Earth in case of an emergency millions of kilometres away from home.
Scientists are building on the success of the International Space Station and robotic missions to Mars to realize the ambition of sending humans to our neighbouring planet. It is an exciting time for space exploration!
Martian landers are stationary robots (controlled from Earth) that sit on the surface of Mars. They send pictures and data back to Earth. A lander can also be the protective shell that delivers a rover to the Martian surface.
Typically single-celled organisms that cannot be seen without a microscope. Bacteria and certain fungi, such as yeast, are examples of microbes.
A spacecraft that orbits a planet and does not land. Some Martian orbiters were sent with attached landers or rovers that were then dropped to the surface of Mars. Orbiters send pictures and data back to Earth.
Martian rovers are mobile robots (controlled from Earth) that drive around the surface of Mars. They are delivered to the surface inside a lander. Rovers send pictures and data back to Earth, as they explore different areas of Mars.
An instrument that uses lenses and/or mirrors to make distant objects appear larger and closer. Telescopes are used to study objects in our solar system (the Sun, planets, asteroids, etc.), other solar systems in our galaxy, and even other galaxies in the universe.
Mars Today: Robotic Exploration: Mars Overview - NASA (Retrieved April 18, 2016). This webpage summarizes NASA's overarching goal for missions to Mars – seeking signs of life.
NASA Rover Finds Conditions Once Suited for Ancient Life on Mars - NASA (Retrieved May 4, 2016). This article discusses how NASA's Curiosity rover found chemicals in rock samples that suggest Mars could have supported microbial life in the past.
Mars Exploration Past Missions - NASA (Retrieved April 18, 2016). This webpage summarizes NASA's completed robotic mission to Mars, including links to detailed mission information.
Mars Exploration Current Missions - NASA (Retrieved April 18, 2016). This webpage summarizes NASA's robotic missions to Mars that are still active, including links to detailed mission information.
Journey to Mars Overview - NASA (Retrieved April 18, 2016). This webpage summarizes how NASA's past and current space exploration paves the way for future robotic Mars missions (InSight and Mars 2020 Rover) and a crewed Mars mission. (A video version was posted March 2, 2016: https://www.youtube.com/watch?v=Oqj3s4RoB_M)
The ExoMars Programme 2016-2018 - European Space Agency (ESA) (Retrieved April 18, 2016). This article provides a summary of the goals of the ESA/Roscosmos ExoMars missions.
SpaceX says it will fly to Mars in 2018 – what are its chances? - New Scientist (Retrieved May 4, 2016). This article discusses SpaceX's plans to land its Dragon capsule on Mars with technical support from NASA.
No Small Steps Episode 1: Getting To Mars - NASA's Marshall Center (Retrieved April 18, 2016). This video discusses the challenges of launching rockets into space and introduces the Space Launch System (SLS) as the most powerful rocket ever made. (Episodes 2 and 3 give details about the SLS rocket boosters and what kinds of fuel SLS will use.)
NASA's asteroid mission isn't dead – yet - Ars Technica (Retrieved May 4, 2016). This article discusses the controversy around NASA's plan to redirect a piece of an asteroid into orbit around the moon to test its Space Launch System before a Mars mission.
Top Ten Ways ISS Is Helping Us Get To Mars - NASA (Retrieved April 18, 2016). This article explains how future Mars missions will benefit from research on the International Space Station, especially with respect to keeping astronauts healthy.