By Bart Van Hove*
1- Why do we keep going to Mars?
There are several reasons. Mars is the most similar planet to Earth, and not very far away. We have developed robust technology to land on Mars, which has reduced cost and increased the amount of scientific return per mission. Financially, we are capitalizing on previous investments. Scientifically, it may seem that the big questions about Mars have been answered. Water has been found (mostly frozen under the surface), and Mars does not seem to be crawling with life (it may still exist under the surface, of which we know little). The focus of Mars science has shifted to its geology, atmospheric dynamics, and climate history. Technologically, it is very challenging to land on Mars. Developments in sensors, digital imaging, communications, robotics, power systems, aerodynamics, navigation, etc. also help technologies on Earth – and Elecnor DEIMOS does research in several of these areas.
2 – Does Mars teach us about Earth?
Mars is an interesting example of an Earth-like planet, which stopped being hospitable to life. The study of Mars involves many of the same scientific methods and models used to investigate Earth. Today’s questions about Mars include how the atmosphere changed so dramatically, how and where most of the water disappeared, how climate and weather are affected by the planet’s motion and orbit around the Sun, and how climate history can be observed in geological data. It is possible that Mars contains large deposits of methane gas, a powerful greenhouse gas, frozen underground. Such deposits exist on Earth, and their sporadic release is a major but uncertain component of climate predictions on Earth. Mars is a fascinating and useful second example of a planet in our Solar System, but which has gradually lost its volcanism, atmosphere, water cycle, and magnetic field, which make Earth such a pleasant habitat for life today.
3 – When will humans visit Mars?
The main challenges for human exploration of Mars are landing technologies, resource generation, and health and safety measures. Elecnor DEIMOS is helping to develop landing technologies in several projects. The current plan by NASA is to explore Mars with humans in the 2030’s. They would stay on Mars several months, before returning to Earth. The first human missions to Mars will resemble the polar exploration on Earth. Scientists, engineers, and doctors will be the first to travel to Mars, for constructing and maintaining temporary research stations. In the 2040’s, a permanent colony could be established. Also depending on political ambitions, most of the technologies could be developed in the coming two decades. An important stepping stone is to bring back rocks to Earth, called Mars Sample Return, using robotic missions. These missions will be the first to launch a rocket on Mars, which makes it back to Earth safely. Already, NASA and ESA are working on a collaborative Mars Sample Return mission. The Perseverance rover takes the first step of storing rocks in containers, which are left on the Martian surface for pick-up by future missions.
4 – Who has landed on Mars?
Actually, the first landing was by Russia, with Mars 3 in 1971. Unfortunately, the Mars 3 lost radio contact minutes after landing. The first really successful landing, which also performed science on Mars, was the NASA Viking mission in 1976. After Viking, NASA performed 6 more successful landings. Landing on Mars is very difficult, and some missions were lost (e.g. the Mars Polar Lander in 1999). Historically, NASA had a strong background to land robotic missions on Mars, after landing humans on the Moon in the 1960’s, and especially returning them safely to Earth.
Europe has almost landed on Mars twice. Both Beagle 2 in 2003, and ExoMars Schiaparelli in 2016, were very nearly successful. This just means the stakes are high for the next European mission, the ExoMars Rover and Surface Platform, in 2022. It is as ambitious as the heaviest NASA missions, and Elecnor DEIMOS has been involved in its development. Later this year, also China will try to land on Mars. The Tianwen-1 mission is already in orbit around Mars. In May of 2021, it will perform Entry, Descent, and Landing. It is China’s first interplanetary mission. Other future European Mars missions, possibly including a successor to ExoMars Schiaparelli, are being studied by ESA and Elecnor DEIMOS.
5 – Is it expensive to go to Mars?
Yes and no. The first successful Mars landers (the Vikings in 1976) would cost about 7 billion EUR today. After this initial investment, later missions can use many components and systems again, which reduces cost. Medium-sized landers, for example the 2008 Phoenix and 2018 InSight missions, cost less than 1 billion. Larger missions, e.g. the 1000 kg Perseverance rover, now cost around 2-3 billion EUR.
Those are big numbers, but they deserve context. The money is spent over several years, sometimes spread over a whole decade. The money mainly comes from government, and is directly injected into the economy. It pays for the development of advanced technologies, and the training of specialized workforces like that at Elecnor DEIMOS. The technology developments also benefit Earth. For example, heat shield materials designed to survive atmospheric entry, can be used to make buildings more fire-resistant. Navigation on Mars and in space is challenging. Navigation solutions developed for space missions, are found on today’s airplanes and drones. Advances in digital image sensors, developed for Mars and other destinations, have found their way into smartphones and computers.
6 – How does visiting Mars help Earth?
In three ways. First, it provides us with a better scientific understanding of how planets in the Solar System are created, how they evolve, and when they can support life. The climate conditions on Mars have changed dramatically, and do not support life anymore. Understanding the climate history of Mars, improves our understanding of Earth. Second, going to Mars is very difficult, and the solutions and technologies developed to achieve it have benefits on Earth. This includes communications, digital imaging, efficient power sources, aerodynamics, sensors, and navigation. Many technologies that were developed for Mars, and other space exploration missions, have found their way into aircraft, consumer products, telephones, communication technology, medicine, and much more. The heat shield materials used to protect a spacecraft during atmospheric entry, can even be used to improve the fire-proofing of steel buildings. Thirdly, visiting Mars has always been a romantic adventure, with strong emotions in both cases of mission success or failure. Setting very ambitious goals is the best way to get younger people excited about science and engineering.
7 – Why is it difficult to land on Mars?
We all played with skipping stones! It’s all about finding the right shaped stone and hitting the water surface at the right angle. A re-entry vehicle has to perform a similar mission, just at hypersonic speed! It must run on a tightrope between burning in the atmosphere and skipping out freezing in space, between fire and ice and between hitting and missing the target.
This is known as the entry corridor and it is driven by the forces and the thermal loads generated by the friction of the vehicle with the planet’s atmosphere.
On Mars the atmosphere is so thin that you have to efficiently produce drag before you hit the ground but it’s also thick enough to produce temperatures of thousands of degrees. Finding the right trajectory is a challenge and the vehicle has to perform a sequence of events such as opening a parachute or igniting engines, in perfect timing. Being at tens of millions of kilometres from Earth this has to be performed in full autonomy. This is why the Mars Entry Descent and Landing is also known as the 7 minutes of terror.
Future technologies to land heavier spacecraft on Mars, for robotic and human exploration, are being researched worldwide and at DEIMOS Space. These include controlled entry, descent and landing, inflatable heat shields or supersonic retro propulsion to precisely land heavier payloads in areas never explored before. They will contribute to make the 7 minutes less terrorific but, if possible, even more exciting!
8 – Can Mars landing technology be used on other planets?
Many of the subsystems needed for planetary exploration, like precise automatic navigation, radio communication power systems, and scientific instruments, are applicable to many other planetary exploration missions. This includes Venus, Titan (a Saturn moon), the gas giants Jupiter and Saturn, and the ice giants Uranus and Neptune. Only Earth, Mars, Venus, and Titan have atmospheres in the Solar System. The atmosphere of Mars is much thinner than at those other destination. As a result, some of the specifics of Mars landing technology would have to be adapted. However, flight qualifying Mars landing technologies, accelerates the technology development for other missions. Likewise, the missions to Mars benefit from developments for other missions. For example, DEIMOS Space is involved in the EFESTO project, which develops inflatable heat shields that can be shared between Earth and Mars landing missions. Another example is the supersonic parachute of the 2016 ExoMars Schiaparelli mission. It was based on the parachute for the Huygens mission, which landed on Titan in 2003.