Humans ins Space

by Manuela Braun

Outer space begins 100 kilometres above sea level – that is, if you adhere to the definition of the International Astronautical Federation (IAF). This is where aviation ends and space travel begins. Only those who have flown above this altitude are considered to be astronauts. But the Association of Space Explorers (ASE) stipulates another condition: to be an astronaut, a person must have completed at least one orbit around Earth. The first human to fulfil both of these requirements was the cosmonaut Yuri Gagarin, who orbited Earth on 12 April 1961 in the Vostok 1 spacecraft. Astronauts have been indispensable to space research since, as they make an important contribution to conducting a variety of experiments under microgravity conditions. While robots or robotic assistants have become capable of taking on or providing support for various tasks, they cannot replace humans when it comes to research.

Humankind’s outpost in space – the International Space Station ISS - orbits the Earth at an altitude of 400 kilometres. It is the biggest collaborative project in space which began on 20 November 1998, when the Russian Zarya module became the first module to be carried into Earth’s orbit. The US Unity module was connected to it 16 days later. On 2 November 2000, the first astronauts – the initial long-term crew – moved into their new home. Since then, this outpost in space has become an important part of space exploration, with over 2500 experiments conducted under microgravity conditions by more than 3600 scientists from 106 different countries. 256 men and women from 22 nations have lived and conducted research on the ISS.

From materials physics to Earth observation

The experiments conducted by DLR on board the International Space Station include investigating the radiation exposure that occurs inside and outside the laboratory module, as well as on the astronauts’ bodies. Through materials physics experiments such as those conducted in the electromagnetic levitator (EML), DLR studies solidification processes to make metallurgical production more efficient on Earth. Among other benefits, this could help to optimise industrial casting processes for turbine blades or motor casings. Earth observation can also benefit from the flying space laboratory. The hyperspectral instrument DESIS (DLR Earth Sensing Imaging Spectrometer) was installed on the MUSES research platform on the exterior of the ISS in 2018 to monitor Earth’s environment and resources. The data acquired indicate changes to the ecosystem on Earth’s surface and make it possible to assess the health of forests, lakes, rivers and agricultural land. These data contribute to the documentation of global change.

Mission to the moon

NASA astronaut Eugene Cernan took the last step on the moon on December 14, 1972. After the Apollo 17 mission, the moon receded from the interest of manned space flight. Now, with NASA's ARTEMIS mission, humans will fly to the moon again before the end of this decade. Their spacecraft will be the Orion capsule. These ‘astronauts’ on board the first Orion flight around the Moon – the ARTEMIS 1 mission this year - will, in fact, be two female phantoms, Helga and Zohra, 95 centimetres tall and made up of 38 layers in which small crystals will record radiation levels on their journey through space. Over 5600 passive radiation detectors, 16 active detectors and a radiation protection vest – this is the equipment with which the DLR space medicine specialists will equip the next two passengers for the MARE experiment (Matroshka AstroRad Radiation Experiment) to determine the radiation risk with greater precision and possibly develop protective measures.

Preserving the astronaut’s health

Greater radiation exposure is just one of the negative effects of prolonged stays under microgravity conditions. If you have ever looked closely at the astronauts floating in front of the camera on the International Space Station (ISS), you will have noticed the effect of weightlessness on the human body: a bloated, pinkish ‘puffy face’ and thin ‘chicken legs’ that quickly set in once the body no longer feels ‘up’ and ‘down’ due to the absence of gravity. A key area of focus is therefore preserving the health of the astronauts: bone and muscle loss, impaired vision, impact on the immune system and cognitive abilities and increased intracranial pressure are health problems in human spaceflight. Research for a better understanding of metabolism and the cardiovascular system and effective countermeasures is thus being conducted within the field of space medicine. The large-scale research facility :enivihab, with an area of 3500 square metres, extends across the DLR site in Cologne like a grounded space-ship.

The negative effects of gravity can be replicated and countermeasures tested under controlled conditions here. Inside the building are a short-arm centrifuge, a PET-MRI, a hypobaric chamber, physiology and biology labora-tories and an area in which the test subjects live during the studies. Re-search is being conducted in the interests of the astronauts’ health, but also to gain a better understanding of the effects of ageing, bedriddenness, immobilisation, and isolation on patients on Earth.

DLR has carried out a large number of bed rest studies in cooperation with partners such as the US space agency NASA, the European Space Agency (ESA) and various universities and research institutions. The first of these was conducted alongside ESA in 2001. In 2015, the RSL bed rest study tested whether training on a horizontal sledge jump system can reduce bone and muscular atrophy. In 2017, the DLR team worked on the VAPER bed rest study with NASA to investigate visual impairment, intracranial pressure and the physiological and psychological impact of a higher proportion of carbon dioxide in the atmosphere. In 2019, AGBRESA marked the first joint DLR, ESA and NASA bed rest study. In this case, the scientists used rides on the centrifuge to expose the test participants to artificial gravity of 1 G.?