Planet Mars. Only when Earth and Mars are “favorable” to each other can a spacecraft reach the red planet in about six months. There is such a favorable position every two years or so.
If there is anything the planets orbit tells us, it is when interplanetary space missions leave. This summer, the planets are in good shape and three spacecraft headed for Mars. Interplanetary traffic has not been as busy since the 1970s.
The Mars satellite left on July 19 Al Amal (translated ‘hope’) from the United Arab Emirates. Four days later, the Chinese satellite and lander Tianwen-1 (“heavenly questions”) on the way. Finally, the American Mars rover traveled last Thursday Perseverance (“perseverance”).
But why do so many rockets go to Mars? Scientifically speaking, all these missions can yield relevant results. But the relative ‘accessibility’ of the planet also plays a role, and the (international) recognition that can be reaped for the space agencies.
Arab Al Amal: the weather on Mars
The United Arab Emirates’ Martial Mission Al Amal is the most comprehensive of the three missions and consists of a satellite that observes the planet from a high orbit (between 20,000 and 43,000 kilometers). On board is a camera and infrared spectrometer that tracks weather and seasonal patterns over a long period of time. The probe sees almost the entire planet in about 55 hours. It is the first probe that can provide such a complete picture of the atmosphere over a longer period of time. An ultraviolet spectrograph also aims to clarify the way in which the Martian atmosphere loses hydrogen and oxygen to empty space. Reportedly, Al Amal cost about two hundred million dollars.
The big question
Science is in great demand for Mars. Is or was the planet ever suitable for life? Almost every modern Mars mission contributes in one way or another to answering that question.
An ocean on Mars once contained more water than the Arctic Ocean. 87 percent of that water has disappeared into space.
In the absence of comparative material, researchers mainly look at the conditions that made life on earth possible. A number of general rules can be drawn from this. “The most important thing is that there is energy (in the form of, for example, heat and light – ed.), Nutrients and liquid water,” said Véronique Dehant, professor of planetary science at the Royal Observatory of Belgium in Brussels. “Traces such as old river beds and deltas show that Mars was habitable until about 3.5 billion years ago. We are therefore now looking for fossil traces of life. ”
Dehant says that her ‘favorite’ mission is the American – she is involved in another American Mars mission InSight and the European-Russian Mars rover Rosalind Franklin (more on that later). “Perseverance will soon land on the bottom of an old lake that has preserved traces of possibly old life,” she says. “The most interesting part of the mission is to store soil samples with possible fossil signs of life for a possible return to Earth.”
Soil research is not only relevant for the search for life. In order to explain the notched traces of liquid water, the planet must have had a thick atmosphere in the past, and yet almost nothing remains today. Most of the atmosphere has probably been lost due to the influence of solar radiation and solar wind that blew the upper layers into space, as it were. And with that Mars also lost its quality of life. The Arab satellite is looking at how that process is (still) taking place, specifically how charged hydrogen and oxygen particles escape into space.
Model (1: 4 scale) of the Chinese Mars rover Tianwen-1.
Chinese Tianwen-1: tripper
The Chinese set off with their Tianwen-1, which consists of a satellite and a lander from which a Mars rover rolls. The satellite and rover together have thirteen scientific instruments. In addition to cameras, radars look for geological structures and possibly water (ice) in the ground. Spectrometers determine the composition of rocks and a weather station measures the temperature and movement of the atmosphere. The mission examines traces left by running water and the Martian magnetic and gravitational field. Until now, the Chinese have left little information about things like the budget, the landing spot and earlier even the launch date.
Buy a mission to Mars
The space agencies behind the new Mars missions are very different. The United States and China have more than half a century of experience. The United Arab Emirates Space Agency, the Mohammed bin Rashid Space Centre, was only established in 2006. This Mars mission is therefore rigged with enormous speed. According to Erik Laan, aerospace engineer and consultant for various space organizations, they had a lot of foreign support. For example, the satellite was assembled in the United States and was launched from a Japanese base. Laan finds the Arab space program a positive development. “They want to show that they are not only good in the oil industry but also participate in new technologies. They are open about this and say they want to inspire young people to create a new generation of scientists and engineers. I believe something like that works. ”
China has been in space travel since the 1970s, but seems to have accelerated in the last ten to twenty years. They built their own modest space station around the earth and had carts on the moon in late 2013 and 2019. They also launch many satellites for observation and communication around the Earth. It is a broad package, which may now include countries on Mars. “Everyone is looking at what the American company SpaceX is doing for new developments, but the fact is that the Chinese have launched the most rockets in recent years and also this year,” says Laan.
Wind tunnel parachute test for NASA’s Curiosity Rover. With a diameter of over fifteen meters, it is the largest parachute ever used for landing on another planet. A person can be seen at the bottom right.
The Americans now rely on a lot of experience when it comes to Mars landings. Since the 1990s, they have safely placed four carts on the red planet, which, according to Laan, is a lot more difficult than landing on the moon. “You arrive at Mars at a much higher speed and have to slow down for more than five kilometers for second to a standstill in an atmosphere more than a hundred times thinner than Earth’s, ”he says. This happens in about seven minutes, sometimes referred to by the parties involved as the seven seconds of terror. “You use a heat shield for braking, but especially opening the parachute is a critical moment. You have to do that at exactly the right speed. ” Relatively many Martian landings went wrong in the past, such as an attempt by a European-Russian probe in 2016.
An impression of the helicopter Ingenuity on Mars.
Perseverance takes a small helicopter flying on Mars. Laan thinks it is spectacular. But is it a nice stunt, or is this really going to yield something? Laan thinks a bit of both. “You can use this to reach places that are unreachable for a robber. But you shouldn’t think about the thing crashing on the rover, so I think they are very conservative with their deployment. ”
Laan is also pleased with the collection of soil samples by Perseverance for a possible return to earth. Such a separate return mission could take place in the 1930s. “Such a mission has been talked about for decades, but he is always lost when making the budgets. It is also very expensive at seven to eight billion euros. Yet you can unleash much better experiments on Earth on the Martian stones. An advanced laboratory for a complete analysis on a microscopic scale simply does not fit on a Mars rover, ”says Laan. “What I don’t understand is that Perseverance doesn’t have a much longer drill. Research shows that in the top one and a half meters we do not have to expect so much in terms of molecules of interest to life. They all break down there because of the strong radiation on Mars. ”
The American Mars rover Perseverance takes a test drive in the cleanroom.
American Perseverance: a small city car
Perseverance is the most advanced Mars mission. NASA reportedly paid $ 2.7 billion for it. Perseverance weighs (on Earth) 1025 kilograms more than a city car and is gently placed on Mars with a ‘floating crane’. His slightly lighter predecessor Curiosity was also presented in a similar way in 2012.
Perseverance is similar to Curiosity. Six aluminum wheels, a long movable arm with a drill. On board are an X-ray spectrometer to determine the composition of the soil, a ground radar that can detect water up to ten meters deep and a weather station. A nuclear battery serves as a reliable energy supply, even when the sun is not shining. New is the MOXIE device, which will make a little oxygen as a technological demonstration by chemically converting carbon dioxide from the Martian atmosphere. Perseverance can also store 43 soil samples for a longer period of time.
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Missed the boat
Drilling much deeper into Mars is reserved for Mars rover Rosalind Franklin of the European and Russian space organizations. And while the rover was as good as ready and Mars was right, earthly things threw a spanner in the works for a launch this summer. Last March, ESA announced that the launch will be shifted to 2022. “It was precisely in Italy, where the corona crisis was most severe, that a lot happened in that mission,” said Laan, who was previously involved in the development of some of the rover’s potential instruments. “Also, the parachute did not meet the requirements earlier this year. They were testing a new version in America when everything was shut down there. ”
So that actually meant four new space missions to a planet, isn’t that a bit exaggerated? Can’t we spread our eyes better in space? “We have learned a lot from previous Mars missions, but there are still many questions about it,” said Dehant. “The geophysical features of a planet are linked to the likelihood of life. Think of the composition of atmosphere and soil, the structure, the nature of the planet’s core and interactions with a possible ocean. We are still interested in more information about the origin and conservation of life on planets. ”
Mars is head and shoulders above the rest of the solar system in this respect, Laan thinks. “This is the only accessible place to look for traces of life. Some moons of large planets, such as Jupiter’s moon Europe (or Saturn’s moon Enceladus – ed.) Are also interesting in that respect, but go there… That is much more expensive and a single journey takes years. Our neighboring planet is relatively approachable in that respect. You can go there in about six months. ”