Image Credit: NASA

Hi, I’m Rachel, the Astronomer here at the Space Centre.

There is another planet in our solar system that humanity is looking to explore – it's dusty, red, and currently populated by robots. These robotic explorers have found lots of evidence that billions of years ago, Mars was once much wetter and warmer, not unlike Earth. The rocky terrestrial planets Venus, Earth, and Mars formed over 4.5 billion years ago from similar materials and building blocks; but they evolved in remarkably different ways, leading to the drastically different appearance and characteristics they have now.

Like Earth, Mars has seasons, polar ice caps, canyons, extinct volcanoes, and an atmosphere – albeit a very thin one. With all these similarities, scientists are wondering whether life ever arose on Mars. Were these early conditions favourable for the emergence of life? If so, how long did that life last? How would microbial life evolve on Mars?

Artist’s impression of an ancient Mars with oceans, based on geological data.
(Credit: Ittiz Source:

These questions lie at the heart of past, present, and future missions to Mars. To answer them, Mars is being studied intensely by spacecraft and rovers alike. In Martian airspace, six orbiters, one rover, and one lander are currently surveying red planet and collecting data. This month (February 2021), they will be joined by others to study Mars.




1. Mars 2020 (NASA) : the rover Perseverance and its passenger, helicopter Ingenuity, will look for signs of life, the processes and history of the Martian climate and geological system, and explore habitability (for humans)
2. Hope (UAE) : this orbiter will be the first probe to provide a complete picture of the Martian atmosphere, and why it’s leaking hydrogen and oxygen gases into space
3. Tianwen-1 (CNSA) : the orbiter and rover will search for signs of life and study Mars’ environment.

But why are all three Mars missions, all from different space agencies, arriving at the planet at the same time? The reason is efficiency. With the help of a little bit of math and orbital mechanics, we can calculate the trajectory (or orbit) which will require the least amount of energy. This fuel-efficient elliptical orbit is known as the Hohmann transfer orbit. However, in order to pull this gravity-assisted maneuver and ‘slingshot’ spacecraft to Mars, executing a Hohmann transfer requires a bit of patience and impeccable timing. Because Earth and Mars orbit the Sun at different speeds, there is a special window – called the launch window – that occurs about every 780 days (or roughly two years and two months) where a Hohmann transfer can be performed.  Space agencies have capitalized on the last launch window, occurring between July-September of 2020. The next window will be in 2022-2023, when we’ll be sending the next cycle of Mars missions to orbit. Such an orbit, specifically the Earth-Mars Hohmann transfer orbit, takes about 258 days (or roughly 9 months) to traverse.

The Hohmann transfer orbit from Earth to Mars. (Credit: NASA)

So, what do we have to look forward to in the future? In the coming years, we’ll add a few more spacecraft to the robot family:

1. ExoMars Rosalind Franklin (2022, ESA/Roscosmos) : a mission to study the astrobiology, water, and atmosphere of Mars
2. Mars Sample Return (2026, International): a series of missions to return samples from Mars by the early 2030s
3. Martian Moons eXploration (MMX 2024, JAXA): a mission to explore Phobos and Deimos, and will orbit both Mars and the moon Phobos to collect data and a sample from the moon’s surface

In its current state, Mars isn’t quite ready for humans yet. However, humanity is taking huge strides toward leaving the first footprints on the Martian surface. Each mission to Mars gives us more scientific data and information on the red planet, so we can prepare for humanity’s first Martian. Where will we go next?

Read more about Mars from our summer 2020 blog, and check out some of the resources below.

Astronomers of All Ages - Playlist

Discover more about the red planet with NASA’s Solar System Exploration site.

Ask yourself: How does the exploration of Mars compare to exploration of other planets in our solar system?


Read this great article that provides an overview of Mars exploration.


Mars has played a starring role in science fiction for over a century. Check out this list of the top 25 science fiction books featuring the red planet. Which have you read?

Ask yourself: Has any of science fiction in these books has become reality?


Preview the landing of Perseverance with this virtual simulator.

Ask yourself: What do you think will the most dangerous part of the landing?


Discover more about gravity assist and if you are really keen dive more deeply into the basics of space flight.

Ask yourself: Which aspect of planning for space exploration do you find most interesting?