AGBRESA – strict bed-rest for 60 days
With his head down and legs lifted upwards, Test Participant B is being rolled towards the centrifuge. Or rather, his bed is. He will not be allowed to stand up for the next two months. From his bed, Test Participant B mainly sees one thing as he travels the few metres from the test station to the centrifuge – the :envihab ceiling. The 5400-square-metre building has been home to ESA astronauts Alexander Gerst, Andreas Mogensen, Timothy Peake and Thomas Pesquet immediately following their missions, in order to study the effects of microgravity on the human body. Since 25 March 2019, the :envihab facility at the DLR site in Cologne has housed the test participants taking part in the AGBRESA (Artificial Gravity Bed Rest Study) project, a joint effort by NASA, ESA and DLR. All 12 of them have been lying in their beds since 14 April##markend##
Ground team for the Earth-based 'mission'
Sixty days lying on a bed tilted six degrees downwards towards the head end – no getting up in the morning, no walking over to the shower, no meals at the dinner table and no evenings watching TV on the sofa. Instead, the body fluids of the eight men and four women are expected to shift and their bones degrade, as happens to astronauts in microgravity conditions. But at least the latter can float around the International Space Station (ISS).
The Earth-based 'astronauts' at DLR's :envihab, also require the support of their own ground team for their 'mission' – doctors, project managers, the DLR study team, assistants, physiotherapists, and international teams of scientists from within DLR and other institutions. In addition, over 50 student support staff members push the participants back and forth on their beds, bring them food and conduct around 150 experiments to examine their muscles, bones, intraocular pressure, circulatory system and cognitive abilities, as well as spinning them on the centrifuge.
On a tight schedule
Although bed-rest might have commenced, things are far from quiet during the day; everything runs at full speed in the test station. The running circuit two rooms across from the participants now lies abandoned, and the springboard is unused in the corner – data was still being gathered here two weeks ago, to be compared with the readings that will be taken after the bed-rest study. Now everything is geared towards the prone participants. One of them needs to be taken to the MRI machine. Another is being brought back from the centrifuge. Lunches are starting to be delivered to the single rooms. Like an orchestra performing a masterpiece in perfect synchronisation, the day shift staff are working through a tight investigation schedule. A table that is the result of almost two years of planning is displayed on a large screen in the test station. Coloured boxes show when each of the participants has to be brought to which experiment, who will have to be given food in their room, when blood samples need to be taken and when blood pressure should be measured. Over 24,000 vials for blood samples had to be prepared for the AGBRESA project. By the end of the study, 650 hours of experiments will have been carried out on the 12 test participants.
The strictly regulated head-down position has not yet become second nature to the participants. One shoulder has to remain in contact with the mattress at all times, food must be ingested while lying on their side, so that the head is not raised too high, and their legs should not be propped up on the bed. The student assistants check that the lying position is being maintained using a monitor. The study is set to deliver large quantities of data, but these must be gathered under very precise conditions. "We are trying to make things as pleasant as possible for our test participants," says Project Leader Edwin Mulder. A doctor visits every day, the participants are asked about the food prepared in the :envihab kitchen three times a week, and a physiotherapist massages and stretches their muscles every other day. If they wish, they can have their bed pushed into the common room for an evening of watching TV together. The participants stay in touch with their families and friends via the internet and by mobile phone – visitors are not permitted in the test station, as it would cause too much disruption and disturb the carefully devised schedule. Instead, the age-old letter is back in fashion; today, four thick envelopes have arrived in the post for the test participants.
From one experiment to the next
The doors of :envihab’s centrifuge module open and Test Participant B is wheeled inside. After being connected to the instrumentation, the participant will be spun on the centrifuge for 30 minutes and be subjected to gravity of one G. This could prove to be an effective countermeasure to the effects of simulated weightlessness, but has never been tested in a long-term study until now. The student assistant places a sign at the entrance: ‘Subject B is in here’. The test participants will be spun on the centrifuge for the next 30 minutes, before someone comes to pick them up and take them to the next experiment. This might be a bed-rest study, but things only quieten down in the evening, with dinner at 19:00, followed by a night's sleep. The team will be back and knocking on the doors of the test participants’ rooms at 06:30 the next morning. It will then be time to take blood pressure readings, saliva samples, and for the doctors to go on rounds …
Once the 12 test participants have completed the first campaign in the bed-rest study, preparations will get underway for the next round of the AGBRESA study in early September. Potential test participants can apply until the end of May. The next 12 participants will be chosen after attending an information evening, undergoing a detailed medical examination and taking part in a psychological interview. Although the ‘mission’ of these terrestrial astronauts may be shorter than the six-month stays typically undertaken by astronauts on the International Space Station (ISS), they are no less demanding.