The entry follows one instrument. There were, by the institute’s count, between 95 and 106 others, and most of them were run by the crew on each other. This piece sets out what the ones with published results found, grouped by what they measured, so that the wrist counters’ record can be read beside them.

The questionnaires

The Penn group, besides the watches, had each man fill in, once a week on his laptop, the Beck Depression Inventory with the suicide question removed “for reasons of cultural sensitivity”, the short Profile of Mood States, a conflict questionnaire written for the study, and a row of 100-millimetre scales from happy to unhappy, healthy to sick, energetic to exhausted, sharp to fatigued, calm to stressed, fresh to tired, good sleep to poor, and low workload to high; 444 of each over seventy-four weeks, with no gaps. Before the hatch closed each man also took a seventeen-item test of social desirability, “distorting one’s self-presentation to make a favorable impression upon others.” The scores, out of 100: a 81, b 69, c 56, d 56, e 25, f 81. The instructions were in Russian for the Russians and English for the rest.

The crew’s averages were those of healthy men: a depression score of 2.2 out of 100 across the mission, a total mood disturbance of 10.4, unhappiness 19.8, stress 14.3, workload 34.8 and highest in the first quarter. The depression score was higher in the second half of the mission than the first, 3.1 and 2.8 against 1.5 and 1.4, and feelings of sickness and confusion rose; vigour was lowest in the second quarter. Nothing in the averages approached a clinical threshold.

The individuals were another matter. Crewmember e reported symptoms of depression in 93 percent of the mission’s weeks: mild in seven of the seventy-four and moderate in one, with “changes in sleep patterns”, “punishment feelings”, “tiredness and/or fatigue”, “guilt feelings” and “loss of pleasure” the commonest items; his average score was 12.1 where the next highest was 0.5, and he scored highest on every scale of distress and lowest, 22.0 out of 100, on vigour. He was also the man with the lowest social-desirability score. Crewmembers a, b and c “checked off none of the 20 items during all 74 administrations.” Crewmember f reported the highest stress, tiredness, workload and poorest sleep; he was the man with the lowest sleep time. The paper draws the inference carefully: “Although crewmember e was the only subject to report these symptoms, it is unclear whether he was the only subject that experienced them, as the other subjects showed much higher social desirability bias scores.” More than half the variance in every self-report, 55 percent on average, was stable difference between individuals, present from the first weeks.

Conflicts were reported forty-one times with mission control and eight times among the crew, 23 of the forty-one in the first half and 12 in the second, with the peak in the thirty days around the landing. Crewmembers e and f reported 85 percent of them, 51 and 34 percent respectively. In the debriefs on the second day outside, each man named the two crewmates he had talked with most; c and d were the names, a was named by nobody and f by one. The paper’s summary: only c and d “showed neither behavioral disturbances nor reports of psychological distress during the 17-month period of mission confinement.”

The badges

Two days a week each man wore a small radio sensor from Bernd Johannes’s group at the German Aerospace Center that registered the presence and distance of the other five sensors and of fixed sensors placed around the modules. Two sensors agreed with each other 91.0 percent of the time, and the badges agreed with a video survey of the facility on day 475 95.7 percent of the time. From the time any two men spent within range the group built a “crew relation time index”, and tested it against a sociometric questionnaire (correlations of 0.35 to 0.55) and against Carole Tafforin’s ethological scoring of the breakfast videos (0.45 to 0.66), but only for the afternoons and only when the men were active; in the mornings, with the crew in their cabins, the badges measured privacy. The index fell across the mission, which the authors found “consistent with Basners’ et al. report concerning crew hypokinesis in the same study,” and reached its deepest minimum for more than a hundred days on day 470, the day the voice link returned, before recovering. The group’s aim, stated plainly, was a system that could warn a crew of “isolation in isolation.”

The belt and the force plate

Daniel Belavý’s group at the Charité in Berlin had the crew wear a belt accelerometer, the actibelt, for six days at a time, thirteen times across the mission, starting on the fourth day. The “activity temperature”, the average acceleration of the body’s centre of mass with gravity removed, “decreased progressively over the course of isolation”; distance walked fell marginally and gait speed did not change, and the one burst of walking, at about day 280, was the session after the departure from Mars. Twenty-eight times during the mission the men did maximal jumps on a force plate and ten single-leg hops: jump power and hop force fell, grip strength did not. The men’s motivation, measured by questionnaire, rose a little. The group’s conclusion was that “prolonged confinement is a form of physical inactivity.” A second study from the institute with King’s College London, using an isokinetic dynamometer every thirty-five days, found calf strength held but quadriceps and hamstring force fell across the 520 days, with vibration exercise and the MDS resistance device giving the best protection. Both groups note that the crew did not always do the volume of exercise prescribed and that “detailed information on exercise actually executed was not made available.”

The radiograms

The institute’s psychologists, with a Hungarian team using the NooJ corpus software, took the 340 written radiograms the crew sent to the ground, 36,659 words in Russian and English, and counted the categories: needs, activity, negation, communication, and composite phrases for commitment, blaming, trust and resistance. The language “discriminated ‘normal range’ phases from those with significant deviations”, with sharp changes in the week of silence and during the landing. The published summary of the whole communication record says the “period of high autonomy was featured by drastic reduction of the number of crew questions and requests”, that key events changed the messages “radically attesting to misperception of time, emotional involvement, want of CC feedback and draining out negative emotions”, and that after the week of silence the crew’s traffic “was noted to become very light.” The institute’s name for the pattern, after Kanas and Manzey, is “detachment”, and it was found again in the SIRIUS runs of 2017 and 2019 in the same chambers.

Values, pictures and the third quarter

Gro Sandal’s group in Bergen gave the crew a portrait-of-values questionnaire at intervals and interviewed them before and after. The men’s perception of how alike they were rose over time and value differences became less of a source of tension; achievement orientation and tradition fell; and “crew members were highly reluctant to express negative feelings towards each other, which increased towards the end of the mission.” The Czech psychologists Iva Šolcová and Iva Poláčková Šolcová, with Alla Vinokhodova, measured emotional energy, work self-efficacy and perceived similarity monthly and found all three rising, with “no evidence for a so-called third quarter phenomenon.” Wang Yue’s own group at the Astronaut Centre of China, scoring the crew’s ratings of standard emotional pictures against four plasma hormones, found the men rating unpleasant pictures more positively as time passed and “a stage-changing pattern of psychological adaptation of the Mars500 crew, which is similar to the third-quarter phenomenon.” The Penn group found no third-quarter effect in any of its measures. The Czech group’s post-mission “flight story” interviews put the high points at New Year’s Eve, video contact with families and the landing, and the low points at communication delays and losses, “misunderstandings with ground personnel”, and the monotony of the second half.

Carole Tafforin’s scoring of the breakfast videos every two weeks, and of a group discussion every month, found the frequencies of personal actions, visual interactions and facial expressions tied to phases of the mission, and verbal communication in English and Russian “associated with place preferences and preferential relationships.” Set against the six who drifted 507 days in the Arctic ice aboard the schooner Tara, the Mars-500 crew showed more collateral acts and more personal actions, and the Tara crew more visual interaction; her conclusion was “that confinement generates stress manifestations vs. isolation, that isolation enhances social relashionships vs. confinement.”

The salt

Jens Titze’s group in Erlangen fixed the crew’s salt at twelve, nine and six grams a day for months at a time, with potassium held at four grams, and collected every urine. Of 27,279 individual servings, 83.0 percent were eaten entirely, 16.5 percent rejected entirely and 0.5 percent partly. Urine recovered 92 percent of the salt eaten, so the men were in long-term balance; but day by day they were not. Sodium excretion rose and fell on a roughly weekly rhythm tied to aldosterone, and total-body sodium swung by 200 to 400 millimoles on rhythms of a month and longer, without change in weight or body water and “independent of salt intake.” A single 24-hour urine, the clinical standard, correctly told a three-gram difference in intake only 49 percent of the time; seven of them, 92 percent. Nobody had controlled a diet that long before, and the result, ESA said in January 2013, “is showing why we participated in the Mars500 study.”

The blood, the arteries, the microbes

Alexander Choukèr’s group in Munich, with the institute’s immunologists, found in saliva and blood “elevated cortisol levels, increased lymphocyte amount and heightened immune responses”, and read them as chronic stress producing “poorly controlled immune responses.” A reanalysis in 2020 of blood DNA methylation found the men’s epigenetic age falling during the mission, with one measure still lower a week after it. Philippe Arbeille’s group in Tours taught the crew to scan their own carotid and femoral arteries, portal, jugular, femoral and tibial veins with a hand-held probe; 80 percent of the scans were usable, no vessel changed diameter, and the wall thickness of both arteries rose by 14 to 28 percent in all six, was still raised two days after the mission and normal six months later. The Berlin group of Hanns-Christian Gunga, with a sensor on the forehead and one on the breastbone recording core temperature for two nights at a time, found normal daily rhythms before the mission, marked changes after 250 days, most pronounced in the sixty-eighth week, and normal rhythms again two weeks after the end; the Chinese group, with EEG caps, found “majority of the crew members’ total sleep time and sleep efficiency were identified reduced” below 450 minutes and 90 percent.

Petra Rettberg’s group at the German Aerospace Center had the crew take 360 samples of air and surfaces from twenty sites at eighteen times. The surfaces carried a community dominated by Staphylococcus and Bacillus, at loads within the space station’s limits, concentrated where the men were most active, with the crew “the main source for microbial dispersal”; opportunistic pathogens and stress-tolerant organisms were predicted to persist throughout, and “the overall microbial diversity dropped significantly over time.” The Bologna group followed the men’s gut flora through the 520 days and for a year after and found it “inherently dynamic, capable of shifting between different steady states”, individual, and resilient; a Moscow metagenomic study of five of the six found the greatest change in the first fourteen to thirty days and only partial recovery two weeks after the end. A reanalysis in 2021 found gut changes in common with astronauts in flight.

What the pile shows

Each instrument measured a different thing, on its own schedule: the questionnaires weekly, the badges two days in seven, the belt six days in forty, the scans every two months, the samples at eighteen points. Each found something. Several disagree with each other on the one question that had a name, the third quarter. And only the wrist counters ran every minute, which is why the entry follows them.

Sources

• Mathias Basner and colleagues, “Psychological and behavioral changes during confinement in a 520-day simulated interplanetary mission to Mars”, PLOS ONE 9 (3), e93298, 2014, CC BY. The questionnaires, Tables 1 and 2, the conflicts, the debrief sociogram. doi:10.1371/journal.pone.0093298
• Bernd Johannes and colleagues, “Wireless monitoring of changes in crew relations during long-duration mission simulation”, PLOS ONE 10 (8), e0134814, 2015, CC BY. doi:10.1371/journal.pone.0134814
• Daniel L. Belavý and colleagues, “Progressive adaptation in physical activity and neuromuscular performance during 520d confinement”, PLOS ONE 8 (3), e60090, 2013, CC BY; Christopher J. Gaffney and colleagues, “The effect of long-term confinement and the efficacy of exercise countermeasures on muscle strength during a simulated mission to Mars”, Sports Medicine – Open 3, 40, 2017, CC BY. doi:10.1371/journal.pone.0060090, doi:10.1186/s40798-017-0107-y
• Institute of Biomedical Problems, International Symposium on the Results of the Experiments Simulating Manned Mission to Mars (Mars-500): Abstracts Book, Moscow 2012: the abstracts of Ehmann, Balazs, Shved and Gushin on the radiograms; Sandal, Bye and van de Vijver on values; Poláčková Šolcová, Šolcová and Vinokhodova on the flight stories; Gunga and colleagues on core temperature; Lv and colleagues on the Chinese biorhythm study. PDF
• D. M. Shved, V. I. Gushchin, B. Ehmann and L. Balazs, “Characteristics of the signal lag effect on crew–control center communications in the 520-day simulation experiment”, Aviakosmicheskaia i Ekologicheskaia Meditsina 47 (4), 2013, abstract; Natalia Supolkina and colleagues, “External communication of autonomous crews under simulation of interplanetary missions”, Frontiers in Physiology 12, 751170, 2021, CC BY. pubmed 24032160, doi:10.3389/fphys.2021.751170
• Iva Šolcová, Vadim Gushin, Alla Vinokhodova and Jiří Lukavský, “Emotional energy, work self-efficacy, and perceived similarity during the Mars 520 study”, Aviation, Space, and Environmental Medicine 84 (11), 2013, abstract; Yue Wang and colleagues, “During the long way to Mars”, PLOS ONE 9 (4), e87087, 2014, CC BY; Carole Tafforin, Aviation, Space, and Environmental Medicine 84 (10), 2013, and Aerospace Medicine and Human Performance 86 (2), 2015, abstracts. pubmed 24279233, doi:10.1371/journal.pone.0087087, pubmed 24261062, pubmed 25946738
• Natalia Rakova and colleagues, “Long-term space flight simulation reveals infradian rhythmicity in human Na+ balance”, Cell Metabolism 17, 2013, abstract; Kathrin Lerchl and colleagues, “Agreement between 24-hour salt ingestion and sodium excretion in a controlled environment”, Hypertension 66, 2015, abstract; ESA, “Choosing the right people to go to Mars”, 16 January 2013. pubmed 23312287, pubmed 26259596, esa.int
• Bing Yi and colleagues, “520-d isolation and confinement simulating a flight to Mars reveals heightened immune responses and alterations of leukocyte phenotype”, Brain, Behavior, and Immunity 40, 2014, abstract; Jamaji C. Nwanaji-Enwerem and colleagues, Cell Reports 33, 108406, 2020; Philippe Arbeille and colleagues, PLOS ONE 9 (1), e83063, 2014, CC BY. pubmed 24704568, doi:10.1016/j.celrep.2020.108406, doi:10.1371/journal.pone.0083063
• Petra Schwendner and colleagues, “Preparing for the crewed Mars journey: microbiota dynamics in the confined Mars500 habitat”, Microbiome 5, 129, 2017, CC BY; Silvia Turroni and colleagues, Microbiome 5, 39, 2017, CC BY; A. V. Mardanov and colleagues, Acta Naturae 5 (3), 2013, CC BY; Nicholas J. B. Brereton and colleagues, Computational and Structural Biotechnology Journal 19, 2021, CC BY. doi:10.1186/s40168-017-0345-8, doi:10.1186/s40168-017-0256-8, PMC3848073, PMC8099722