Back to Venus armed with laboratory findings

Venus's impenetrable atmosphere has long made it difficult to conduct a thorough investigation of our neighbouring planet. In a step forward, by conducting laboratory experiments scientists from the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt; DLR) have now developed a way of determining the nature of the planet's surface using new instruments from orbit. The entire surface of Venus can now be mapped mineralogically for the first time, addressing a large gap in planetary research. Venus is Earth's sister planet. It is almost exactly the same size and orbits on average only 40 million kilometres closer to the Sun. However, the two planets developed in very different ways. On Earth, continents formed, separated by oceans. Then some three and a half billion years ago, life emerged under its atmosphere and evolved into the vast variety of organisms that we know today. Things happened very differently on Venus, which is surrounded by an atmosphere of gas a hundred times thicker than that of Earth. Within it, the extreme greenhouse effect results in a constant surface temperature of 470 degrees Celsius - a temperature at which water would instantly evaporate and even lead would melt. The planet is permanently enveloped in thick clouds of sulphuric acid, making it impossible for telescopes on Earth or instruments on board spacecraft to acquire even a glimpse of the surface. Scientists have managed, however, to map its landscape using radar. And now, through a series of laboratory experiments, DLR researchers have developed a new method for determining the nature of the planet's surface from orbit.

"For a good ten years, we have been using a unique laboratory facility to measure the emission properties of various rocks of the kind we might expect to find on Venus under the same extreme conditions that prevail on the planet," says Jorn Helbert, Head of DLR's Planetary Spectroscopy Laboratory (PSL) and lead author of a research paper that has now been published in Science Advances magazine. "The reflectance and emissivity of rocks change when they are exposed to the high temperatures that you find on Venus. As a result, spectral profiles measured at terrestrial temperatures cannot simply be applied there. But now, we have a tool that we can use as the basis for new instruments on the next planned missions to Venus that will finally allow us to determine which types of rock exist there."

Concordance with existing surface measurements from Venus
The four-person research group made up of researchers from DLR, the Planetary Science Institute in Tucson, Arizona, and Mount Holyoke College in Massachusetts have used the results of their laboratory experiments to devise a new 'spectral library' for various types of rock. "Determining the emission spectra in this way has enabled us to reconstruct the iron oxide content at the landing site of the Soviet Union's Venera 9 and Venera 10 landers for the very first time," says DLR Planetary Scientist Alessandro Maturilli. "In 1975, the two landers transmitted images from Venus and provided important measurements. However, they were not equipped with an instrument that could directly measure iron oxide content."

The two landers provided the only direct spectral measurements of Venusian rocks. The emission profiles determined in the laboratory and the spectra determined by the Venera missions are in very good agreement. "As such, we have demonstrated the accuracy of our new method, which represents a big step forward," says Jorn Helbert. Although further Venus lander missions are currently under discussion, global mapping of the planet can only be conducted from orbit. However, the atmosphere of Venus is impenetrable to wavelengths of visible light - those that the human eye can see. To make mapping of the surface possible despite the planet's atmosphere, scientists are focusing on what are known as 'atmospheric windows'. These are narrow bands of wavelengths at which the atmosphere of Venus is transparent, and thus allow a view of the surface. Five such 'windows' exist at wavelengths close to 1000 nanometres (one micrometre). These wavelengths are in the near-infrared, which is adjacent to the visible portion of the electromagnetic spectrum (approximately 400-700 nanometres).

Venus returns to the focus of planetary research
Through their experiment, the researchers have shown that for rock types measured in the laboratory, the spectra and their characteristic profiles can be used to reliably identify them from orbit. "Our aim is now to create the first global map of rocks on Venus," says Helbert. "That would be a major achievement! After all, we know far too little about Venus. In its infancy, the planet may have had water, like Earth, and may also have been less hostile to life." The scientists are looking to use the Venus Emissivity Mapper (VEM) instrument to implement their plan, mapping emissions in the few atmospheric windows available at near-infrared wavelengths. VEM could be installed on the EnVision mission of the European Space Agency (ESA) and on NASA's VERITAS orbiter later this decade.

Venus, Earth's celestial neighbour and often described as its sister planet, was the first target for interplanetary spacecraft. The Soviet mission Venera 1 launched in 1961 and the American Mariner 2 in 1962. Despite a number of spectacular successes, particularly the Soviet space programme's initial orbiters and then eight landings between 1970 and 1983, the planet named after the Roman goddess of love later fell somewhat out of favour in planetary research. Between 1990 and 1994, NASA's Magellan orbiter mapped Venus using radar, revealing myriad details of its multifaceted surface in high-resolution. From 2006 to 2015, ESA's Venus Express mission investigated the planet across a series of seven experiments.

However, we still know little about the nature of the planet's surface. For Earth's other immediate neighbours, the Moon and Mars, determining rock types, mineralogical composition and the abundance of chemical elements was far easier. As a result, nowadays we have a fairly thorough understanding of them. The astronauts involved in the Apollo missions and the robotic missions of the Soviet Union returned 400 kilograms of sample material from the Moon to Earth. Half a dozen landers have been able to analyse the rocks on Mars. A landing on Venus would be a heroic feat, as the lander descends into an increasingly hot oven. The high temperatures and atmospheric pressure - which reaches 92 bar on the ground (equivalent to the pressure at 900 metres underwater on Earth) - would put the electronics under immense strain. The Venera 13 lander was able to withstand these conditions for the greatest amount of time so far and, on 30 October 1981, succeeded in transmitting data from the furnace-like surface of Venus for almost two hours. The new method developed in this laboratory study would allow the surface of Venus to be studied systematically from orbit over a period of many years, without having to run the risk of a landing.

Germany invests 3.3 billion euro in European space exploration and becomes ESA's largest contributor

The German delegation at the European Space Agency (ESA) Council Meeting at Ministerial Level, 'Space19+', was headed by the Federal Government Coordinator of German Aerospace Policy, Thomas Jarzombek, who is a member of the Federal Parliament. He was accompanied and supported by representatives from the Federal Ministry for Economic Affairs and Energy (Bundesministerium fur Wirtschaft und Energie; BMWi) and the Federal Ministry of Transport and Digital Infrastructure (Bundesministerium fur Verkehr und digitale Infrastruktur; BMVI). Walther Pelzer, German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt; DLR) Executive Board member responsible for the Space Administration, also participated in the negotiations. Together with his team from the Space Administration in Bonn, Pelzer prepared working-level German position papers for the meeting in consultation with Federal Government officials. At the end of the conference, Thomas Jarzombek stated that: "After two days of intensive negotiations, Germany has committed a total of 3.3 billion euro for European space programmes over the next three to five years. In setting out our priorities, we have shown that we are a reliable partner for ESA. To achieve our goal of strengthening small and medium-sized German space companies, we have doubled our funding for the relevant programmes. To address the challenges of climate change, Germany has increased its investment in Earth observation to 720 million euro. We have also succeeded in enabling the European lunar mission with a high level of commitment - 55 million euro."

At 'Space 19+', a total of 14.4 billion euro were committed. At 22.9 percent, Germany is now ESA's largest contributor, ahead of France. Specifically, Germany has committed approximately one billion euro to the ESA mandatory programmes. In addition to the general budget, these include the science programme and the European Spaceport in French Guiana. Approximately 2.3 billion euro of the German contribution will go towards what are referred to as the optional programmes: ~720 million euro for Earth observation, ~330 million euro for telecommunications, ~160 million euro for technology programmes, 84 million euro for space situational awareness and security, ~490 million euro for space transport and operations, and ~550 million euro for human spaceflight, microgravity research and exploration.

The German financial commitments in detail

Launch systems
From the end of 2020, Ariane 6 will be the new European launcher for carrying payloads into space, and Germany will contribute ~23 percent of the total development costs. The industrial prime contractors are ArianeGroup, with sites in Germany at Bremen and Ottobrunn, and MT Aerospace in Augsburg and Bremen. Germany is contributing a total of ~90 million euro to the further development of Ariane 6, including the preparation of the future upper stage. Germany is investing ~230 million euro in the optional Launchers Exploitation and Accompaniment (LEAP) programme and will be investing ~95 million euro for the operation and modernisation of the European Spaceport in French Guiana up until the end of 2024.

Germany is participating in the Future Launchers Preparatory Programme (FLPP) with ~137 million euro. The focus will be on the development of a cost-effective lightweight upper stage (for example, constructed using carbon-fibre reinforced composite materials), improving the performance of existing and new engines (Vulcain NEO, Vinci Evolution) and the implementation of new processes and methods (for example, additive manufacturing). Under the name 'Commercial Space Transportation Services and Support' (CSTS), ESA is taking forward a new optional programme in the context of NewSpace. Germany is contributing ~28 million euro to the 'Commercial Space Transportation Services' element, which broadly supports industry in the development of new space transport services, particularly in the field of microlauncher technology.

Science
The Science Programme makes a significant contribution to the development and maintenance of Europe's space infrastructure. It finances research satellites and their launch and operation. The scientific instruments are developed by the Member States themselves. By 2035, 11 new missions will have been launched to explore and analyse the Solar System and the Universe at large. With a budget contribution of 20.7 percent of the total, Germany is the largest contributor to this programme, committing ~578 million euro over five years. Large and medium-sized missions with significant German participation are: Solar Orbiter (solar research, scheduled launch: 5 February 2020), JUICE (Jupiter mission, scheduled launch: 2022), EUCLID (dark energy/dark matter, planned launch: 2022), PLATO (exoplanet mission: 2026), ATHENA (X-ray telescope mission: 2031) and LISA (gravitational wave observatory: 2034).

Earth observation for climate protection and collaborative development
Germany is a world leader in Earth observation - both in scientific and technological terms, and in the use and processing of data for the analysis of the Earth system. With ~520 million euro (30 percent of the budget), Germany will retain its leading role in the currently operational Copernicus European Earth observation programme. This will involve the further development and expansion of the system to include new satellites (Sentinels 7-12) and services for climate monitoring and climate protection, agriculture, mobility, security and disaster prevention. German expertise could also be incorporated into the planned Copernicus hyperspectral mission.

In addition, Germany is contributing ~170 million euro (~26 percent) to the 'FutureEO' scientific programme. Ten million (out of 50 million euro) has been allocated to the new 'Global Development Assistance' (GDA) programme. 'InCubed+' is aimed at short-duration commercial Earth observation activities with private sector backing -Germany is contributing 15 million euro. In addition, Germany is supporting a small Arctic satellite mission (Demonstrator, NewSpace approach) to improve short- and medium-term weather forecasts in the Arctic region with 7.5 million euro.

Telecommunications
In telecommunications (ARTES programmes), the aim is to support innovative technologies and products for the global commercial market. The main focus is on the Core Competitiveness (CC) programme, optical communications (ScyLight), commercial applications (Business Applications and Space Solutions; BASS), Secure Satcom for Safety and Security (4S) and the Partnership Programme. With a financial contribution of 80 million euro for ScyLight and 60 million euro for 4S, Germany has secured a leading role. In the CC Programme, Germany increased its contribution to 67 million euro and doubled its BASS contribution to 37 million euro. Germany contributed 65 million euro to the Partnership Programme, including Electra with an in-orbit demonstration, and 13 million euro to the framework programme for the support of satellites needed for the 5G mobile communications networks.

"Germany is very well positioned in the satellite telecommunications sector. Our aim is to increase the competitiveness of components and support system capabilities with a focus on secure communications - the keyword here is quantum encryption - to integrate satellite technology and applications into the new 5G mobile networks and above all to continue technological and political leadership in optical laser communication," says Walther Pelzer. One example is the planned optical communication network Hydron, which is designed to provide fast connections for users with high data transfer requirements, supplementing and complementing the terrestrial fibre optic network.

Space security
Space weather, observations of near-Earth objects and space debris are as relevant to science as they are to society. Germany is therefore contributing some 12 million euro to the core element of this programme. In addition, Germany will provide 60 million euro for the Hera mission and assume responsibility for system management. Together with NASA's Double Asteroid Redirection Test (DART) mission, Hera will investigate how asteroids can be diverted from their trajectory where there is a risk of collision with Earth. HERA's target is the double asteroid Didymos / Didymoon. The craft will perform observations and analyses in connection with the impact of the NASA DART spacecraft on the smaller asteroid, Didymoon, planned for September 2022. The findings will be used for fundamental research as well as for the preparation of possible defence missions against asteroids. Germany is also contributing ~12 million euro to a mission for the active removal of space debris (ADRIOS).

Technology development
German participation in the General Support Technology Programme (GSTP) aims to maintain, expand and strengthen the industrial competitiveness of small and medium-sized enterprises (SMEs), particularly start-ups. New priorities include the digitalisation of production cycles, technologies for the sustainable use of space, Industry 4.0 compatible production methods, robotics and modern sensor technologies, AI-supported applications on satellites, and the development and use of quantum technologies. Germany has increased its contribution by a factor of 2.5 to 160 million euro. The programme aims to close existing gaps in technological development and focuses on the maturation of core technologies and components for future missions.

E3P - the European Exploration Envelope Programme
All robotic and astronautic exploration activities will be brought together under the 'European Exploration Envelope Programme' (E3P). This combines the European science and technology programme for the use of near-Earth orbits for space research with the exploration of the Moon and Mars. Sub-programmes will be the operation of the ISS and its utilisation (German share: 416 million euro). As the principal constructor and funder of the European Service Modules (ESM 1-4), the supply component of the US Orion spacecraft, Germany is an indispensable part of NASA's Artemis lunar programme.

This is supported by a strong role for SMEs, which Germany is aiming for through its subscription of 25 million euro for European gateway activities. In addition, Germany will play a leading role in the sustainable robotic exploration of the Moon with a contribution of 55 million euro. Germany is also contributing 20 million euro to the Exploration Preparation, Research and Technology (ExPeRT) programme, which will conduct mission studies and technology development for other exploration topics, including a commercial approach. For the consolidation of ExoMars (launch: July 2020) and selected technology elements of the 'Mars Sample Return' mission being planned in cooperation with NASA, Germany is providing ~37 million euro.

Testing the value of artificial gravity for astronaut health

Test subjects in Cologne, Germany will take to their beds for 60 days from 25 March as part of a groundbreaking study, funded by European Space Agency ESA and US space agency NASA, into how artificial gravity could help astronauts stay healthy in space. Carried out at the German Aerospace Center's (DLR) :envihab facility, the long-term bedrest study is the first of its kind to be conducted in partnership between the two agencies. It is also the first to employ DLR's short-arm centrifuge as a way of recreating gravity for participants. But just how easy is it to stay in bed for 60 days and what is the relevance of adding artificial gravity for space researchers? We pull back the covers on this unique investigation as preparations get underway. Bedrest has long been used to mimic some of the changes our bodies experience in the weightlessness of space. Humans are made to live on Earth and without the constant pull of gravity it is common for muscles and bones to start wasting away. Currently, astronauts on board the International Space Station exercise for up to 2.5 hours per day and maintain a balanced diet to help mitigate microgravity's effects, but scientists believe adding a dose of artificial gravity could be key during longer-term missions. Though it may sound simple for the 8 male and 4 female volunteers involved, lying in bed for a full 60 days, plus a further 29 days of acclimatisation and recovery, is not quite as restful as it seems. Throughout the course of the study, all 24 participants will need to remain at :envihab on the DLR campus. There they will be kept in beds with the head end tilted 6 below horizontal and must ensure one of their shoulders is touching the mattress at all times.

As blood flows to their heads and muscle is lost from underuse, researchers will investigate changes and test techniques from diet to physical exercise. Artificial gravity is one of the techniques under the spotlight this time around and will see some of the participants sent spinning.

Recreating gravity
Once a day, a selection of the study's participants will lie in DLR's short-arm centrifuge. There they will be spun to encourage blood to flow back towards their feet and allow researchers to understand the potential of artificial gravity in combating the effects of weightlessness.

The intensity of the centrifugal force is able to be adapted to each person according to their size. DLR can also adjust the centre of spin so that subjects are spun around their heads or their chests. Changing the position in this way could have far-reaching consequences for rehabilitation but, as this is a new domain, these consequences are currently unknown.

A number of different experiments will be carried out over the course of the study, looking at cardiovascular function, balance and muscle strength, metabolism and cognitive performance among other factors. Seven of these experiments will be conducted by European-led research groups, with a view to validating the findings on the International Space Station during future missions.

An international effort
ESA team leader for research Jennifer Ngo-Anh says the international nature of the long-term bedrest study reflects the international collaboration necessary as ESA plans future missions to the Moon and beyond.

"To make these missions possible, various risks to astronaut health must be minimised. This study allows us to address the issue of muscular atrophy caused by weightlessness, but also other stressors such as cosmic radiation, isolation and spatial restrictions."