When Neil Armstrong became the first man to set foot on the Moon July 20, 1969, Thomas Reiter was 11 years old and watched the event glued to the television screen. A good 26 years later, on September 3, 1995, Reiter is an astronaut himself and on his way to the Russian space station Mir. Part of the mission is a spacewalk - the first to be undertaken by a German astronaut. 2006 a mission to the ISS followed. Reiter spent a total of 350 days in space, making him the European with the second longest stay in space after Alexander Gerst. After his active career as an astronaut, Reiter joined the Executive Board of the German Aerospace Center (DLR) in 2007, where he was responsible for space research and development. From 2011 to 2015, he was Director of Human Spaceflight and Operations at the European Space Agency (ESA). Today, Thomas Reiter is a consultant to ESA Director General Jan Wörner and coordinator for international space agencies.
Let your thoughts drift back to July 20, 1969. Do you remember where you were and how you watched the lunar landing?
Thomas Reiter: Indeed, I do. I was eleven years old at the time. It was an event you never forget. It was early in the morning and my father had woken me. We had been invited to the neighbors, who already had a color TV! The transmission was in black and white of course, but the documentaries before that were shown in color, I still remember it very well. We all sat in front of the TV together and watched Neil Armstrong take his first steps. And, to be quite honest, there wasn’t really much else to see. Still, it was an incredible moment.
Springen Sie bitte mal gedanklich zum 20. Juli 1969. Wissen Sie noch, wo Sie waren und wie Sie die Mondlandung gesehen haben?
Thomas Reiter: Aber natürlich. Ich war damals elf Jahre alt. Das war ein Ereignis, das man nicht vergisst. Es war frühmorgens, mein Vater hatte mich geweckt. Wir waren bei Nachbarn eingeladen, die hatten schon einen Farbfernseher! Die Übertragung war natürlich schwarz-weiß, aber die Dokumentationen davor wurden in Farbe gezeigt, daran erinnere ich mich noch genau. Wir saßen dann alle zusammen vor dem Fernseher und haben die ersten Schritte von Neil Armstrong verfolgt. Wobei man sagen muss, dass nicht wirklich viel zu erkennen war. Dennoch: Es war ein unglaublicher Moment!
What went through your mind as you were watching the TV? Can you still remember?
Reiter: Yes, I can. I wondered what it must feel like to stand on the surface of another celestial body. And this enthusiasm has never faded to this very day. This idea still arouses in me the same enthusiasm today as it did back then.
A human landing on the Moon is an entirely different challenge. Humankind held its collective breath on that day.
What is the Moon?
The Moon is the Earth's faithful companion. It orbits the Earth at a mean distance of 384,400 km and, with a diameter of 3476 km, is about a quarter of its size. The Moon is thought to have formed about 4.5 billion years ago when the proto-Earth collided with another celestial body. The impact hurled matter from the Earth's crust and the mantle of the impacting body into an Earth orbit, where it massed together to form the Moon. The energy of the impact also led to the impacting body merging with the proto-Earth, forming the Earth.
Der Mond ist der treue Begleiter der Erde. Er umkreist die Erde in einem Abstand von 384.400 km und ist mit einem Durchmesser von 3476 km ungefähr ein Viertel so groß. Entstanden ist der Mond vor etwa 4,5 Milliarden Jahren, als die Protoerde mit einem anderen Himmelskörper kollidierte. Durch den Aufprall wurde Materie aus der Erdkruste und dem Mantel des einschlagenden Körpers in eine Erdumlaufbahn geschleudert, wo sie sich zusammenballte und schließlich den Mond formte. Die Energie des Aufschlags führte zudem dazu, dass der einschlagende Körper mit der Protoerde zur Erde verschmolz.
Why do planets have moons?
The Earth is not the only planet orbiting the Sun with a companion. With the exception of Mercury and Venus, all planets in our solar system are orbited by moons. The number of moons is varied: while Mars has only two moons, Saturn and Jupiter both have several dozen. But how do planets get to have moons in the first place? The formation process described for Earth's moon, the collision of two large celestial bodies is not the norm. The Earth and its moon are relatively similar in size, whereas the moons of the other planets are much smaller in comparison. These moons are either asteroids captured by the gravity of the planet or they formed billions of years ago together with their planet by the agglomeration of matter. Therefore the largest planets in our solar system, Saturn and Jupiter, are also the planets featuring the highest number of moons.
Die Erde ist nicht der einzige Planet, der einen Begleiter aufweist. Bis auf Merkur und Venus werden alle Planeten in unserem Sonnensystem von Monden umkreist. Die Anzahl der Monde ist dabei sehr unterschiedlich: Während der Mars lediglich zwei Monde besitzt, haben Saturn und Jupiter mehrere Dutzend. Aber wie kommen Planeten überhaupt zu Monden? Die für den Mond der Erde beschriebene Entstehungsgeschichte durch den Zusammenprall zweier großer Himmelskörper ist nicht der Regelfall. Dafür spricht auch der geringe Größenunterschied zwischen Mond und Planet. Die Monde der anderen Planeten sind im Verhältnis deutlich kleiner und sind entweder durch die Schwerkraft des Planeten eingefangene Asteroiden oder vor Milliarden von Jahren gemeinsam mit ihrem Planeten durch die Zusammenballung von Materie entstanden. Dadurch erklärt sich auch die hohe Anzahl der Monde von Saturn und Jupiter: Saturn und Jupiter sind die größten Planeten in unserem Sonnensystem, der Saturn ist zehnmal und der Jupiter elfmal so groß wie die Erde.
Is there life on the Moon?
The Moon is a rather inhospitable celestial body. Unlike the Earth, it has no atmosphere and the surface temperature is subject to high fluctuations due to the slow rotation - the Moon rotates only once per revolution around the Earth. Thus the temperature is about 130 °C during daytime and drops to -160 °C at night. Due to the lack of atmosphere, meteoroids hit the Moon on a regular basis, pockmarking the surface with craters. In contrast to the sand found on the Earth, the regolith, the largely pulverized rock material which covers the Moon, was not formed by wind and water, but rather by the constant impacts of other celestial bodies. For this reason the Moon dust is not round in shape, but sharp-edged and consists to a large extent of electrostatically charged nanoparticles. The lack of atmosphere also means that any water exposed to the solar radiation inevitably escapes into space. Water in the form of ice can only be found in permanently shaded areas, for example in some craters in the polar regions. To date, only tiny traces of water have been found in the regolith. All in all, the Moon is a hostile celestial body. However, in 2010 scientific research has enabled OHB to create a controlled environment, which allows higher plants to grow on lunar soil. Since then, the technology has been further developed and represents a decisive step towards the feasibility of a future Moon base.
Der Mond ist ein eher unwirtlicher Himmelskörper. Anders als die Erde besitzt er keine Atmosphäre und die Oberflächentemperatur unterliegt aufgrund der langsamen Rotation -der Mond dreht sich pro Umlauf um die Erde nur ein einziges Mal- hohen Schwankungen. So beträgt die Temperatur mit der Sonne im Zenit ungefähr 130 °C und fällt in der Nacht auf -160 °C. Aufgrund der fehlenden Atmosphäre schlagen auf dem Mond zudem immer wieder Meteroiden ein, die die Oberfläche mit Kratern überziehen. Auch das oberflächliche und weitgehend pulverisierte Gesteinsmaterial, das Regolith, das den Mond bedeckt, wurde anders als irdischer Sand nicht von Wind und Wasser geformt, sonders ist durch die ständigen Einschläge anderer Himmelskörper entstanden. Aus diesem Grund ist der Mondstaub nicht rund geschliffen, sondern scharfkantig und besteht zu großen Teilen aus elektrostatisch aufgeladenen Partikeln mit einem Durchmesser im Nanometerbereich. Die fehlende Atmosphäre führt zudem dazu, dass jegliches Wasser, das von der Sonne beschienen wird, unweigerlich in den Weltraum entweicht. Lediglich in dauerhaft beschatteten Gebieten kann sich Wasser in Form von Eis halten. Im Regolith konnten bisher lediglich winzigste Spuren von Wasser nachgewiesen werden. Alles in allem ist der Mond somit ein lebensfeindlicher Körper. Durch wissenschaftliche Forschung ist es bei OHB allerdings bereits 2010 gelungen, eine kontrollierte Umgebung zu schaffen, in der höhere Pflanzen auf Mondgestein wachsen können. Seitdem wird die Technik weiterentwickelt und stellt in Hinblick auf die Versorgung einer zukünftigen Mondbasis einen entscheidenden Schritt dar.
Why does the Moon shine?
The Moon itself does not shine. And since its entire surface is covered in dark grey regolith, its mean planetary albedo, i.e. its mean reflectivity, is not even particularly high at 0.12 either. For comparison: the Earth's mean planetary albedo is 0.31 and Saturn's moon Enceladus, which is covered by ice, even has a mean planetary albedo of 0.99. The planetary albedo is calculated from the ratio of reflected to incident light. An albedo of 0.12 thus corresponds to 12 % reflected light. The fact that the Moon nevertheless appears dazzlingly bright in the night sky in comparison to the stars is partly due to its proximity to Earth. In addition, the human eye adapts to the lower light conditions. At night, the pupils open wide, allowing more light to reach the retinae, which is why the moon appears much brighter than it actually is.
This is interesting because alongside Alexander Gerst you are the German who has spent the most time in space. Still, it must be quite different to actually land on another celestial body ...
Reiter: ... definitely!
Reiter: From an altitude of 400 kilometers you can see the curvature of the Earth, but you don’t see the planet as a whole in space. That’s one of the differences. You also know that in an emergency you can get back to the surface of the Earth from the ISS within three and a half hours. And finally, it is a different technical challenge to land on a celestial body. Apollo 11 bounced over a crater with the last drop of fuel it had before actually landing.
So, you’re saying that the flight on board the ISS was not exciting enough for you.
Reiter: (laughs) I’m deeply grateful to have had this opportunity. But landing on the Moon as a human being is simply an entirely different challenge. Humankind held its collective breath on that day. The whole world sitting on the edge of their seats is something I don’t think we have seen in this form ever again.
The last humans landed on the Moon in 1972 and no one has been there since. How did the view of the Earth from the Moon change humanity?
Reiter: The image of the Earth rising over the lunar horizon was transmitted back to the Earth during the Apollo 8 mission at Christmas 1968 and has massively influenced people’s sense of what the Earth really is. It shows that the Earth is only a small, vulnerable dot in the infinite blackness of space. You also have this feeling to some extent when you view the Earth from the space station, but not in the same way. This impression is certainly amplified many times over the further you move away from the Earth. The awareness of our environment, the sense of what our planet really is, was completely changed by this image.
The view of the Earth from space makes us realize that we can only solve the problems facing the world by working together but never if everyone only looks out for their own interests. This is one of the core insights of space flight.
Today, consciousness of the Earth’s vulnerability to climate change, the destruction of the environment and other problems is far greater than it was 50 years ago. Wouldn’t it be important for this reason alone to enable as many people as possible to expand their consciousness in this way?
Reiter: You’re absolutely right about that. I also think that all my fellow astronauts would agree. Alexander Gerst has also said this on various occasions. It is only the view of the Earth from space that makes us realize that we can only solve the problems facing the world by working together but never if everyone only looks out for their own interests. This is one of the core insights of space flight. And what’s more, it is only when people acknowledge this at an emotional level that it has any effect. Images of probes alone are not capable of generating this change of consciousness.
How many people have been on the Moon?
How many Apollo missions were there?
NASA's Apollo program included a total of 17 missions. Primarily known, however, are Apollo 8, Apollo 11 and Apollo 13. The mission AS-204, later renamed Apollo 1, where all three astronauts died in a ground test, also gained sad fame.
Apollo 1: Apollo 1 was designed as the first crewed mission of the Apollo program. The astronauts Virgil Grissom, Edward White and Roger Chaffee were scheduled to fly a test version of the new Apollo spacecraft into low Earth orbit on February 21, 1967. During a launch rehearsal test at Cape Kennedy Air Force Station Launch Complex 34 on January 27, 1967, a fire broke out in the pure oxygen atmosphere of the capsule, killing all three astronauts. The launch of the mission was cancelled and all manned Apollo flights were suspended for 20 months while the cause of the fire was investigated.
Apollo 8: Apollo 8 was launched on December 21, 1968. It was the mission within the Apollo program that brought the first humans into lunar orbit. Frank Borman, James Lovell and William Anders orbited the moon ten times before returning to Earth on December 27, 1968. During the mission, William Anders took a photograph of the Earth rising above the lunar horizon. This picture, later titled “Earthrise”, has become world-famous, as it shows the fragility of the Earth in the vastness of space.
Apollo 11: After all the necessary maneuvers had been tested in the Moon's orbit during the Apollo 10 mission in May 1969, it took NASA only a few weeks to launch Apollo 11. On July 16, 1969, NASA astronauts Neil Armstrong, Edwin Aldrin and Michael Collins departed from Kennedy Space Center in Florida and reached the Moon's orbit on July 19. While Collins remained behind in the command module of the Columbia spacecraft, Armstrong and Aldrin took the Eagle Lunar Module and made a soft landing on the lunar surface the next day. A few hours later, Armstrong descended the ladder of the Lunar Module and became the first human to set foot on the Moon. Aldrin followed a little later. Around 600 million people around the world watched the event on television.
Apollo 13: Apollo 13 was the seventh crewed mission in the Apollo space program and the third intended to land on the Moon. NASA astronauts James Lovell, John Swigert and Fred Haise set out from Kennedy Space Center in Florida on April 11, 1970. On April 13, 1970, at a distance of around 300,000 kilometers from Earth, one of the two oxygen tanks in the spacecraft's service module exploded. As a result, the water, oxygen and power supplies collapsed. The mission had to be aborted and Apollo 13 had to return to Earth as quickly as possible. Since the condition of the main engine was unknown after the explosion, the astronauts had to perform a swing-by maneuver using the gravitational field of the Moon to set course for Earth. Since the few remaining resources of the command module had to be saved for re-entry, the astronauts used the lunar module as a "lifeboat". The lunar module’s life-support system, however, had not been designed to sustain three people for the four-day return flight. The air purification system was overloaded and had to be equipped with an adapter improvised from bags, flight plans, adhesive tape and even a sock, to connect it to the air purification system of the command module. In order to conserve the limited reserves of the lunar module, the astronauts had to switch off all electrical consumers that were not essential for survival. As a result, the temperature inside the lunar module dropped almost to the freezing point. The astronauts stayed in the lunar module until the last possible moment, changing into the undamaged landing capsule only a few hours before re-entry. On April 17, 1970, the mission came to a happy ending: Lovell, Swigert and Haise splashed down safely in the Pacific and were picked up by a US warship.
NASA later called the mission a "successful failure", as the astronauts returned to Earth unharmed despite the catastrophe. Only a few months later, in January 1971, Apollo 14 reached the Moon and landed on the site originally intended for Apollo 13.
This all sounds like you think that it’s time to send people to the Moon again.
Reiter: Yes, I think it would make a lot of sense...
... probably also because there is still so much to discover on the Moon.
Reiter: Of course. To answer this question properly, let’s take a step back: what expectations were there in the early seventies? It was assumed that things would continue as they had started. Humans had been on the Moon for a few days at a time, and the next step was to build a lunar station. However, these plans didn’t eventuate. Why not? Because in those days, the Cold War was mainly about demonstrating technological leadership and space capabilities.
But today things are different ...
Reiter: ... of course. A lunar mission is highly interesting from a scientific point of view. The Moon would tell planetary researchers a great deal about the origins of the solar system and particularly about our Earth. The consensus opinion of researchers today is that the Moon originated from a gigantic impact by a meteorite on the primordial Earth four and a half billion years ago. This means that the conditions prevailing on Earth at that time have been frozen in time on the Moon, so to speak. That is why there is so much to learn and find out. That’s the scientific side.
What other aspects are there?
Reiter: Economic ones. There is evidence that significant resources lie slumbering on the Moon. Water is held in the polar regions. Water is an important resource for a longer stay on the Moon as you can drink it, convert it into hydrogen and thus energy, electrolyze it and produce oxygen for breathing. This is important because it would mean that all these resources would not have to be carried to the Moon from the Earth. There are also indications of deposits of raw materials such as rare earths, but it remains to be seen whether it would be worth mining them.
The Chinese recently caused a sensation when they landed a probe on the dark side of the Moon. Why was this so significant?
Reiter: The side of the Moon facing away from the Earth is an excellent observation point for radio and optical astronomy. Above all, it is important for planetary defense.
What does this mean?
Reiter: It is crucial to be able to detect at an early stage whether an asteroid is on a collision course with the Earth in order to deflect it. This is important for the security of the planet. Moreover, the Moon is also a wonderful springboard for further journeys into space, because it has only one sixth of the Earth’s gravitational pull.
You have given three good reasons to return to the Moon. Which one of them is the most important?
Reiter: Not all three can be fulfilled at the same pace. Given the current possibilities for transportation that we have, it is hardly conceivable for resources to be carried from the Moon to the Earth. So, we would probably use the resources locally. Take water for example: if you could find water on the Moon and use it for self-sufficiency, you could stay on the lunar surface for a longer period of time. Consequently, our first priority should be to fly to the polar regions in order to perform these local activities. However, a number of technological steps are still required before we can start producing water for self-sufficiency purposes. We must first prove that this is technically possible before we start transporting humans to the Moon in the second half of the next decade.
When you say people in the second half of the next decade, are you talking about Europeans?
Reiter: This depends on the role that we are willing to play in these activities. With the service module for Orion and possible elements for the Lunar Orbital Platform, we at least have the possibility of gaining a seat at the table, this being a prerequisite for an astronaut from Europe to be able to get to the Moon in the future. The purpose of the Lunar Orbital Platform is to land people on the surface of the Moon. This shows that the lunar project is now more long-term and sustainable in nature than it was at the beginning of the 1970s. If we can get involved here, I think it is very likely that a European will stand on the Moon some day. That would be my wish and I believe that it will be possible in the second half of the decade.
Let’s go one step further: how realistic and, above all, sensible is it to travel to Mars?
Reiter: As things currently stand, it is not yet technically possible. We still have to complete some technical groundwork before we can do this.
What aspects require further work?
Reiter: Protection from radiation, for example. There’s no protective magnetic field on the journey to Mars. Then there is the question of supplies. With the propulsion systems available today, the journey would take two years and all the provisions needed would have to be carried on board. So, before you consider such a scenario, you first have to test it with shorter distances. Accordingly, it is logical not to embark on such an adventure until the technologies required have been developed. When you are ready, you can then take the leap from the Moon.
But Elon Musk says he wants to settle on Mars in 2025 ...
Reiter: ... it’s great for Elon Musk to be able to attract attention to himself with such a vision. Yet, I doubt whether the ability to build an admittedly great launcher is enough on its own to get to Mars and back again. We’re simply not far enough down the road to make this happen by 2025. Visionaries are important to drive us forward, but what they say must also be technically feasible. They don’t have any magic formula. It is not possible to defy the laws of physics.
OHB founder Manfred Fuchs was a visionary of a very different kind. He was advocating a German lunar mission many years ago. In retrospect, how would you rate OHB’s lunar activities?
Reiter: Back when I was responsible for space research and development at DLR, we tried to execute a national lunar mission. This mission was driven not least of all by the ideas that Manfred Fuchs had developed. It was important for such a mission to be endorsed by research institutions and agencies and also to be actively supported by industry. And this was the case with OHB and Manfred Fuchs. This mission was only a hair’s breadth away from reaching fruition.
We can see the Moon every evening and it is the subject of legends and great stories. Above all, however, it is within our reach.
OHB founder Manfred Fuchs also wanted reach the Moon
OHB founder Prof. Dr. h. c. Manfred Fuchs was always fascinated by Moon research and promoted the implementation of corresponding projects. As part of the Mona Lisa project initiated by Manfred Fuchs, program proposals for the exploration of the Moon were developed, which can now be found in the lunar programs of DLR and ESA. In the NEXT Lunar Lander (later renamed to Lunar Lander) study conducted under the direction of OHB, key technologies for an autonomous precision landing were developed on behalf of ESA between 2007 and 2010 in preparation for the soft landing of probes and manned landing modules on the lunar surface.
After his death in 2014, Manfred Fuchs was honored by a special commemorative mission: On October 23, 2014, the Manfred Moon Memorial Mission (4M) was launched from the Chinese Xichang spaceport as a piggyback payload of the Chang'e 5-T1 lunar probe. While passing the Moon, the 4M probe sent messages, which were previously fed into the system by the Fuchs family, friends and companions of Manfred Fuchs, in a continuous loop. The messages were received by radio amateurs from all over the world.
When was this?
Reiter: In 2008, 2009. But unfortunately it didn’t work out for various reasons. The project was then taken to a European level. The Lunar Lander was tabled at the Conference of Ministers in 2012 but ultimately failed for financial reasons. I greatly regretted that decision.
Back to you again: Imagine you are at the beginning of your career, so you could start from scratch again. Would the possibility of landing on the Moon be something that would motivate you?
Reiter: Yes, absolutely. I believe that this has something to do with the fact that we humans are genetically predisposed to always exploring the unknown. This disposition is more pronounced in some people than in others. Yet, the basic tendency to discover new things has always been a driving force for humanity. We want to overcome borders. We can see the Moon every evening and it is the subject of legends and great stories. Above all, however, it is within our reach. I have no doubt that people will return to the Moon one day. And to return to your question: of course I would attempt to land humans on the lunar surface again. I find it fascinating to get to places that technology rather than evolution can take us. I still get goose bumps when I imagine it, just like when I was eleven and sitting in front of our neighbors’ TV set to watch Neil Armstrong take his first step on the surface of the Moon.