Moon

It is the only celestial body (except the Earth) on which humankind has left its footprint – the astronauts of NASA’s Apollo 11 mission were the first ones in 1969. In 1970, the Soviet Union landed the first remote-controlled vehicle on another celestial body: “Lunochod”. In 2024, the USA intend to take humans to the Moon again – as a preparation for a subsequent Mars mission.

In fact, there are concrete plans for the future to choose the Moon for settling on a foreign celestial body for the first time: China is planning to build a Moon station for astronauts in the late 2020s.

© ESA - T. Reiter

ESA is pursuing plans for the Moon, too, from a moon station to the use of moon water. For solving the problem of expensive transport of building material, an interesting idea came up: the Moon consists of rock, with which a 3D printer could be fed that would be able to print the materials for a complete building within one week. The technology is working; it has been tested on Earth with moon-like rock.

© Dr. Barbara Imhof, LIQUIFER, “Growing structures: bioinspired innovation insights for architecture and robotics”, as part of Living Machines 2020 July 28, 2020.

The #Mars “Mole” by DLR

In 2018, NASA’s InSight probe landed on Mars. On board: the DLR experiment HP. The ram penetrometer hammers itself into the Martian soil to measure its thermal conductivity – this knowledge can contribute to a better understanding of the history of Mars (and of all planets). Moreover, a seismometer listens underneath the Martian surface after quakes to provide better insights on the inner structure of Mars.

© DLR CC BY 3.0

In 2021, the ExoMars mission of ESA and Roskosmos is to drop a large Mars rover on the surface to search for traces of life. Since then, the possibility to build a Mars station where astronauts could live – or at least launching manned spaceflight to Mars – has been investigated by ESA and NASA. The time may come in the 2030s. At present, first tests are carried out that first and foremost deal with the long journey: how do humans behave if they have to live in a very confined space and isolated from the environment for hundreds of days?

© ESA/ATG medialab

Mars – the cosmic brother of the Earth. Since 2003, the Mars Express probe has been orbiting Mars. It is continuously transmitting new, spectacular, high-resolution images (in stereo and in colour) for creating a map of Mars. At the pole caps of Mars, water ice (thickness: one kilometre) has been detected. Finally, in 2012, NASA’s Mars rover Curiosity has landed, which is not only transmitting images but brought a drill and analysis instruments with it. In 2013, at the borders of an old riverbed (evidence for former running water), the “components of life” (hydrogen, oxygen, carbon, nitrogen, phosphor, and sulphur) were found. So, there is a theoretical possibility that life would have originated on Mars about four billion years ago.

© ESA/NASA/DLR/RPIF

Sun

ESA’s Solar Orbiter probe was launched in 2020 into an orbit around the Sun. With hitherto unprecedented precision, the probe will investigate how the Sun creates and influences its heliosphere – this space full of particles and force fields that influences the Earth as well. What is the origin of solar wind? How is the coronal magnetic field of the Sun generated? How do turbulences develop? How do electrically charged particles behave? And how do they originate? A NASA probe, too, is currently exploring the Sun: Parker Solar Probe, which will deliver insights about solar winds and stardust (= falling stars).

© ESA/AOES

Pluto

Previously it was considered a small planet; today it is classified as a dwarf planet. The NASA probe New Horizons is exploring it right now, after a long journey that started as early as 2006. The aim: to learn more about the geology, chemical composition, and atmosphere of Pluto. Before the mission, our image of Pluto was very indistinct.

Today we know: there are 4,000-metre mountains consisting of adamant cold water ice with a temperature of -230 °C and enclosed hollows with a depth of 3,000 metres as well as glaciers consisting of frozen nitrogen and frozen methane. What additional mysteries will this icy wonderworld reveal? A mission with a lander could find out more.

Jupiter

In 2016, NASA’s probe Juno reached it (as successor of NASA’s Galileo mission). Is its core rocky? What data are delivered by gravitational and magnetic field? How much water is in the atmosphere (there are clouds of water ice)? And oxygen? What is it all about the thunderstorms that can reach velocities of more than 600 kilometres per hour, and – as clearly visible in the picture – drive clouds in front of them? And: how did Jupiter originate in the first place? The first good images of Jupiter were delivered by the Galileo mission (from 1989 to 2003) and, in 2000, by the Saturn mission Cassini-Huygens during fly-by.

Jupiter ice moons (e.g. Europa)

Ganymed, Europa, and Callisto – all of them are icy Jupiter moons. The JUICE mission of ESA is scheduled for launch in 2022 and will reach the ice moons presumably in 2030 to reveal their secrets, for example, the composition of the ice or the oxygen content in the atmosphere. Interesting aspect: underneath their ice crust, oceans of liquid water are presumed – a possible habitat for simplest life-forms.

Mercury and the MESSENGER probe

2011: NASA’s MESSENGER probe, as the first probe ever – entered into an orbit around Mercury, the planet closest to the Sun and delivered data for a period of four years. MESSENGER is delivering ten thousands of measuring values and high-resolution surface images. Thanks to these images, it could be proven that there is volcanic activity on Mercury, which, in turn, implies a liquid core. Truly surprising: there is plenty of water on Mercury, however, only in the exosphere, the outermost layer of the atmosphere. DLR scientists are evaluating data from several instruments for this mission.

In 2018, the BepiColombo mission of ESA and JAXA (Japan) was launched. Supposedly it will take about seven years to reach Mercury. Its aim: to answer hitherto unclarified questions regarding Mercury (inner composition, magnetic field, and other things) and to draw conclusions as to the genesis of our solar system.

Venus

ESA’s Venus Express probe orbited Venus from 2006 to 2014 – with the aim to research on the climate and weather on Venus in order to get a better understanding of climate mechanisms and climate change. Because of the thick cloud coverage (thickness: 20 kilometres), you can hardly see anything with a telescope from Earth. This is why the probe generates infrared images. First insights: there is an ozone layer in the atmosphere as well as a thin layer of dry ice (carbon dioxide). Moreover, lightning is much more frequent than on Earth. Oceans might have existed in former times, too. Furthermore, huge volcanos can be found on Venus – with a diameter of up to 700 kilometres.

Saturn and Cassini

Since 2004, the Saturn orbiter Cassini has been observing many fascinating phenomena in the Saturnian atmosphere and radioed extraordinary images and measuring data to Earth. Thanks to Cassini, ten new moons could be discovered. In 2014, Cassini instruments proved that on the moon Enceladus, besides geysers, there is a subsurface sea consisting of liquid salt water. And where water can be found, life could exist (microorganisms) – or could have existed. Larger molecules were found that could be precursors of amino acids – and thus of life …

Titan (Saturnian moon) and Huygens

On January 14, 2005, the atmospheric probe Huygens as part of the Cassini/Huygens mission flew through the atmosphere of the Saturnian moon Titan for two and a half hours, explored it and shortly after landed with a parachute and fully functional on the surface of the cold trabant with a temperature of -180 degrees Celsius.

Titan, a moon the size of Mercury, distinguishes from the relatively small Saturnian ice moons. Its surface is less dominated by water, instead, there are large-scale seas of methane and ethane. On this moon alone, a hundred times more “natural gas” is stored than on Earth.

It is raining methane from the clouds of Titan. In total, the atmosphere and the surface of this moon form a unique chemical low-temperature laboratory, in which complex, “exotic” processes are running from the view of Earth standards. These processes have been further researched on the spot by the Cassini orbiter until the end of 2017.

Kuiper belt

Pluto is not alone far afield in our solar system. It is located in the Kuiper belt, a region full of icy objects in the shape of a donut that begins at Neptune. There, hundreds of thousands of objects could be existing with a minimum diameter of 100 kilometres. Some of them are dwarf planets like Pluto that partly have their own moons. In the picture: Arrokoth, discovered in 2014 with the Hubble space telescope and inspected in 2019 by the NASA probe New Horizons in fly-by. As yet, Arrokoth, 35 kilometres in length, is the space object farthest from Earth that has been explored by a probe.

Gaia maps the Milky Way

Unfortunately, there is no good map of our galaxy, the Milky Way, available as yet. To change this, the Gaia mission was started in December 2013, a telescope that generates images of about one million pixels through the largest digital camera in space. The map will initially cover one per cent of the Milky Way. 1.7 billion stars have already been measured. ESA reckons that, among other things, about 7,000 new planets will be discovered outside our solar system. More information on the mission is available in an app named “Gaia Mission”.

Hayabusa1: mission to the Itokawa asteroid with return ticket

Itokawa. An asteroid. A cosmic piece of rock flying across space. The Japanese Hayabusa1 mission approached it (distance: about Earth–Sun), touched down despite technical problems, collected samples – and flew back again. In doing so, scientists succeeded for the first time in returning a probe from a far-away celestial body. This was such a great challenge, since from the outset the double amount of fuel had to be transported. In addition, the probe was not to burn up upon re-entry into the Earth’s atmosphere.

With Hayabusa2 on the way to Ryugu

In 2014, the Japanese Hayabusa2 mission took off to the Ryugu asteroid. In 2019, the probe dropped off the landing module MASCOT that had been developed in Germany. For research purposes, MASCOT is equipped with a radiometer, a camera, a magnetometer, and a spectrometer. In 2019, Hayabusa2 took soil samples at several places and brought them to Earth in a capsule that landed with a parachute.

MASCOT

The German MASCOT lander does not have its own propulsion system and landed uncontrolled on Ryugu’s surface since it was simply ejected from the probe. Due to minor gravity, it impacted nine times with low velocity. However, that was exactly the plan since a propulsion unit has a considerable weight and remote control from Earth makes no sense given the signal runtime of 17 minutes per direction. Thus, MASCOT had to orientate itself by means of sensors (it was lying on its back) and “turn” to the right side. For “getting up”, a pivot arm is installed in the interior that enables change of position and even bouncing.

OSIRIS-REx fetches samples from Bennu

Bennu is an asteroid with its own orbit around our Sun. It might be possible that it will collide with Earth in the next century (probability: 1:2700 – roughly comparable with that of four numbers in lotto). NASA’s probe OSIRIS-REx set off in 2016, arrived in 2018, takes samples with one arm in fly-by and is scheduled to return to Earth in 2023 and drop off the container with the samples. An astonishing discovery: the asteroid is not static, it has strong temperature fluctuations, and hurls out particles that might measure ten centimetres.

Rosetta flies to Churyumov-Gerasimenko

From 2014 to 2016, the comet Churyumov-Gerasimenko had been the research target of the Rosetta mission. Rosetta orbited the comet core at different distances and accompanied it on its orbit around the Sun. Upon its approach to the Sun, it was strongly heated up and emitted gas and dust particles that were exactly measured. In this way, one could very well observe how a comet changes over time. Above all, the landing of the DLR lander Philae was a scientific and technical sensation – after a ten-year journey.

Vesta, Ceres, and probe Dawn

„Dawn” is the NASA mission that started in 2007 to the asteroids Vesta (arrival 2012) and Ceres (arrival 2015). Since their evolution four and a half billion years ago, both celestial bodies have presumably hardly changed at all. They are located in the asteroid belt between Mars and Jupiter. They are ideal research objects to cast a glance far back into the past, virtually back to the “dawn” of our cosmic home. Dawn discovered organic molecules on Ceres … was life possible there in former times? The size of Ceres makes it a dwarf planet like Pluto.

Probe Voyager 1

Voyager 1 was launched by NASA in 1977. As the first man-made object it entered interstellar space in the year 2012, meaning it left our solar system. And it is continuing its flight at a speed of 61,000 kilometres per hour and will never return. Its flight route amounts to 520 million kilometres per year. Viewed from Earth, the probe is now in the Ophiuchus constellation. It will have enough fuel for position alignment up to 2025, however, presumably it will not make it to the next star. It will take Voyager 40,000 years until it reaches the “vicinity” of the Gliese 445 star, however, the distance in fly-by will still be 1.6 lightyears.

Alpha Centauri

Alpha Centauri is the solar system closest to ours. It is “only” 4.34 lightyears away and has two suns. Which planets are orbiting these suns and whether there are traces of life on them is still unexplored. One star in this triple star system is Proxima Centauri, which is orbited by Proxima Centauri b. As yet, it is the only planet outside our solar system known to mankind – and there might be the possibility that it is habitable.

Hubble

The space telescope Hubble, launched in 1990, has been the first telescope in space and carries several instruments on board that have been exchanged and improved over the years time and again. The biggest advantage of a space telescope: from space, you have a clearer view on the universe, without disturbing atmosphere. For 25 years now, Hubble has made important contributions to various astronomic fields (planet research, cosmology, and exploration of different objects and processes in our galaxy).

JWST

JWST, the James Webb Space Telescope, is to be Hubble’s successor starting 2021. Its place of deployment will be at a distance of 1.5 million kilometres from the Earth orbit instead of near the Earth like that of Hubble. A giant: with a weight of 6.5 tons and a telescope mirror diameter of 6.5 metres.

JWST will be in operation for ten years, and, among other things, search for (infrared) light from the first stars and galaxies after the Big Bang. Moreover, JWST – similar to Hubble – will make a contribution to a complete series of scientific issues around the evolution, development, and structure of outer space. Science is hoping to get new insights as to the evolution of stars, planets – and life.

Cheops

We have relatively comprehensive knowledge about stars, that means suns – about 1.7 billion of them have already been mapped. However, we only have sparse knowledge on the roughly
4,000 planets that have been identified so far using different methods. With the help of the small space telescope CHEOPS, several hundreds of (exo)planets which have been detected by using a certain method should be monitored with another method which determines their density. In this way, it becomes clear whether they are rock, ice or gas planets.  

Euclid

Euclid, a new space telescope of ESA, was developed to explore dark matter and dark energy for a period of about six years starting around 2022 (from the Lagrange point L2, an orbit at a distance of 1.5 million kilometres from the Earth). As yet, it is not clear what dark matter consists of. Since it does not emit light, its presence can only be derived from the effect of its gravitational force. It is assigned an important role in forming the structure of the universe. Without its gravity, galaxies, stars and planets – and thus life on Earth – would not have been able to develop. It is virtually the glue holding our universe together. However, up to now, the composition of this dark matter has not been clarified.

From the deviation of the light caused by dark matter, the distribution of the dark matter itself is to be determined. To this end, researchers aim to draw conclusions as to the geometry of the universe from the data.

We know even less about dark energy than we do know about dark matter. According to today’s model of the cosmos, its share of dark energy is 75 per cent. Dark energy is to be accountable for the fact that the universe is expanding faster and faster. Scientists are hoping for first insights on the nature of this dark energy from the Euclid data.

Plato

Under what conditions do planets evolve – and how did life originate? Plato is a space-based telescope presumably starting in 2026 that will intensify the search for planets and other stars. It is to scan millions of stars to find out, if any and which planets are orbiting them.

Plato does kind of an “inventory” of planetary systems – scientists are hoping for answers to the questions “What particular planetary systems are existing?” and “What does their structure look like?” All the same or all different?

Who knows? Perhaps Plato will find a second Earth.