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Assessment of the effects of isolation, confinement and hypoxia on space-flight piloting performance for future space missions -The SIMSKILL experiment in Antarctica

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Abstract and Figures

Interplanetary human missions to Mars and beyond will suppose a very demanding physical and psychological environment for future astronauts. Isolation, con nement, hypoxia or hypercapnia in a reduced pressure atmosphere, darkness and other factors are expected to endanger a mission's success, directly in uencing human performance. In order to study the e ects of such environmental conditions on human beings, the SIMSKILL Experiment aims to investigate how spacecraft piloting performance decays over time by deploying a Soyuz ight simulator on the Antarctic research stations Halley VI and Concordia, which feature similar living conditions as those of a space mission, leading to muscular atrophy, loss of cognitive capacities, and reduction of psycho-motor skills. This paper o ers an up-to-date analysis on the recorded data from the scienti c campaigns in Antarctica, compared to those of the control group subjects in Stuttgart. An overall total of 69 subjects and more than one thousand approach and docking ights to the ISS performed in the simulator have been analysed using mathematical models. The results obtained from this analysis show how the in uence of isolation, con nement and hypoxia in Antarctica is crucial to understand how di erences in performance appear between subjects. A thorough assessment of collective trends is presented, by showing how reaction times, error events, visual perception, among others, are essential parameters to understand a pilot's skill evolution and propose optimal training and maintenance of acquired skills should be de ned in future space missions.
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Assessment of the eects of isolation, connement and hypoxia on space-ight
piloting performance for future space missions - The SIMSKILL experiment in
Miquel Bosch Brugueraa,
, Andreas Finka, Valerie Schrödera, Emilie Dessyb, Floris P. van den Bergc, Greig
Lawsond, Carole Dangoissec, Carmen Possnigc, Nadja Albertsenc, Nathalie Pattynb, Reinhold Ewalda
aInstitute of Space Systems, University of Stuttgart, Pfaenwaldring 29, 70569 Stuttgart, Germany
bRoyal Military Academy, Rue Hobbema 8, 1000 Brussels, Belgium
cEuropean Space Agency - ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, Netherlands
dBritish Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom
Interplanetary human missions to Mars and beyond will suppose a very demanding physical and psychological en-
vironment for future astronauts. Isolation, connement, hypoxia or hypercapnia in a reduced pressure atmosphere,
darkness and other factors are expected to endanger a mission’s success, directly inuencing human performance.
In order to study the eects of such environmental conditions on human beings, the SIMSKILL Experiment aims
to investigate how spacecraft piloting performance decays over time by deploying a Soyuz ight simulator on the
Antarctic research stations Halley VI and Concordia, which feature similar living conditions as those of a space
mission, leading to muscular atrophy, loss of cognitive capacities, and reduction of psycho-motor skills. This paper
oers an up-to-date analysis on the recorded data from the scientic campaigns in Antarctica, compared to those
of the control group subjects in Stuttgart. An overall total of 69 subjects and more than one thousand approach and
docking ights to the ISS performed in the simulator have been analysed using mathematical models. The results
obtained from this analysis show how the inuence of isolation, connement and hypoxia in Antarctica is crucial to
understand how dierences in performance appear between subjects. A thorough assessment of collective trends is
presented, by showing how reaction times, error events, visual perception, among others, are essential parameters
to understand a pilot’s skill evolution and propose optimal training and maintenance of acquired skills should be
dened in future space missions.
Keywords: Soyuz, Antarctica, Human Performance, Flight Simulator, Hypoxia, SIMSKILL
?This document is part of the research project funded by the Fed-
eral Ministry for Economic Aairs and Energy (BMWi) with Funding
Nr. 50WB1531.
??The presented article has been selected from the proceedings of
the 70th International Astronautical Congress, Washington D.C., 21-
25 October 2019.
Abbreviations: BAS, British Antarctic Survey; DLR, Deutsches
Zentrum für Luft- und Raumfahrt; ESA, European Space Agency;
FA, Final Approach; FF, Frequent Flyer Group; IF, Infrequent Flyer
Group; IPEV, Institut Polaire Français, Paul-Émile Victor; ISS, Inter-
national Space Station; NASA, National Aeronautics and Space Ad-
ministration; PNRA, Programma Nazionale die Ricerche in Antar-
tide; RF, Regular Flight; RMS, Root Mean Square
Corresponding author
Email address:
(Miquel Bosch Bruguera)
1. Introduction
1.1. Background
The investigation and assessment of astronaut skills
has been a key focus-point since the very beginning of
human space-ight. The search for an optimal train-
ing methodology with the aim of maximizing human
performance in space has become an essential aspect
for the success of crewed space missions. The method-
ologies to analyse and improve astronaut performance
have been constantly upgraded while new technologies
appeared. Consequently, the radical improvement of
computing performance has allowed, not only to dras-
tically improve the reliability and performance of rock-
ets and spacecraft, but also to enhance in the develop-
Preprint submitted to Acta Astronautica August 11, 2020
ment of training and evaluation tools for the crew, and
accordingly, improve the astronauts’ performance.
The analysis of piloting performance has undergone
a radical change with the availability of more real-
istic ight simulators and more sophisticated statisti-
cal models that require higher computational perfor-
mance. Statistical analyses by usage of linear models
have been proposed by Salnitski, Dudukin, Johannes et
al. [1] by assessing the relation between ight relia-
bility and the so-called "psychophysiological cost", in
order to understand which are the human factors that
dene a pilot’s performance. The ndings by Salnit-
ski and Johannes state that an intermission of about 30
days without training deteriorate ight reliability sig-
nicantly, although this can be recovered quickly with
latter training sessions. The assessment of piloting per-
formance is expected to play even a bigger role in the
future, where longer space missions might require long
training breaks among the crew.
The goal of space agencies and private companies
to perform interplanetary human missions in the up-
coming decades, principally within the Artemis pro-
gramme and ESA’s Lunar roadmap [2], requires a mul-
titude of preliminary research and development pro-
cesses, in order to enable the proper understanding
of the challenges presented by such missions and en-
sure their success. In the case of long duration human
space-ight, the existence of critical psychological and
physiological factors could put in risk the normal de-
velopment of a deep space mission. The environmen-
tal conditions in which astronauts will be exposed will
be partly unknown and require new approaches when
dening the training procedures, as explained by Ngo-
Anh and Rossiter [3]. As a consequence, space agencies
and other scientic institutions have been performing
research on both real space missions in the ISS and pre-
vious orbital laboratories/stations (see Johannes et al.
[4]), in ground-based, simulated mission environments
(the so-called analogue missions [5, 6, 7]) as well as in
certain scientic facilities such as Antarctic research
stations (Ngo-Anh et al. [8]) , natural caves, lava tubes
and underwater facilities such as the ESA CAVES and
NASA NEEMO programmes (Bessone et al. [9], von
Eherenfried [10] , Todd and Reagan [11]). Such envi-
ronments oer the possibility to develop and test new
frameworks and procedures based on the future Lunar,
Martian and other foreseen space ights. One of the
most singular platforms where to put in practice a real-
istic space simulation is Antarctica, which has captured
the interest of the space community for a long time, as
the living conditions are of full isolation, forcing the the
crew-members to be fully autonomous in every task.
Figure 1: Concordia Station. Credits: M. Bosch Bruguera
The European Space Agency is coordinating a series
of experiments in the Franco-Italian Concordia station
and the British Halley VI station in Antarctica (see Fig-
ure 1) in order to investigate the eects of isolation,
connement and hypoxia on astronauts during long-
term space missions. The implementation of space-
related experiments in such environments permits to
research of critical aspects of crewed missions and en-
hances the development of counteractive solutions for
current and future applications.
The dierent environmental conditions to which the
subjects are exposed, as well as their own personal con-
dition, are expected to play a big role on how their per-
formance evolves throughout the one year overwinter-
ing experiment, as explained by Sgobba and Sandal [12]
and Kanas [13]. Hence, the eects of isolation and con-
nement in Concordia and Halley VI, plus hypoxia in
Concordia, should be stressors for a faster performance
decay. Table 1 shows the details of each research sta-
1.2. Goals
The SIMSKILL experiment (SIMulation SKILLs), is
a research project carried out by the University of
Stuttgart and the Royal Military Academy of Belgium,
and collaborating with the University of Rome "La
Sapienza", in the framework of the Antarctic research
opportunities oered by the ESA. SIMSKILL aims to
investigate how piloting performance evolves during
the overwintering campaigns in Antarctica, by mak-
ing use of an adapted and transportable Soyuz-TMA
space-ight docking simulator (see Figure 2). The main
research questions that this experiment targets are as
Performance degradation: Understand and as-
sess in which measure does piloting performance
Research facility Environmental factors Crew origin
Halley VI Station Isolation, connement UK
Concordia Station Isolation, connement, hypoxia FRA, ITA + Research Medical Doctor (EU)
IRS Stuttgart Normal lifestyle DE
Table 1: Research platform details.
evolve and potentially decrease due to the eects
of isolation and connement, as well as hypoxia,
and extend the ndings to future long-term space
Training Enhancement: Identify how previous
training aects a pilot’s performance and propose
eective solutions for the enhancement of astro-
naut performance.
Furthermore, this experiment expects to obtain a
better understanding on how subjects interact with the
cockpit and nd out which features should be present
in order to enhance mission safety and reliability.
Figure 2: Participant during a Soyuz simulator test at the Concordia
Station. Credits: M. Bosch Bruguera / I. Bruni
2. Methods
2.1. Participants
The subjects of the Halley VI and Concordia stations
were personnel already selected by the respective polar
institutes (BAS, IPEV and PNRA) meant to perform sci-
ence, maintenance and station keeping. The diversity
in tasks and qualication of the crew in all four Antarc-
tic campaigns was high. Each crew was provided by
at least two medical doctors, a cook, technical per-
sonnel responsible for station maintenance, and scien-
tic crew-members such as glaciologists, astronomers
and meteorologists. Consequently, age, qualication
and computer knowledge/gaming backgrounds were
implicitly very diverse. The selection of the control
group participants was tted to the crew distribution
in Antarctica, in order to oer comparable results. In
Figure 3 the age distribution of all experiment subjects
can be observed.
20 30 40 50 60 70
Figure 3: Age distribution of all 69 participants
2.2. Experiment Protocol
The experiment protocol proposed by SIMSKILL is
designed in a way that dierences between groups can
be recognized, depending on the living conditions the
participants experience during the campaign, thus un-
derstanding whether isolation and hypoxia, as well
training frequency, play a signicant role in the de-
velopment and reliability of piloting skills. Additional
parameters such as age, gender, background, etc. will
also be considered. As seen in Table 2, a total of 69 par-
ticipants completed the experiment successfully. Two
Campaign Subjects Female Male
Halley VI 2015 10 2 8
Halley VI 2016 11 3 8
Concordia 2018 12 1 11
Concordia 2019 12 2 10
IRS Stuttgart 2016 25 5 20
Total 69 (+1 drop-out) 13 (18,8%) 56 (81,2%)
Table 2: Subjects overview for each Antarctic campaign and control study.
overwintering campaigns in both Halley VI and Con-
cordia were performed. In addition, a control group in
Stuttgart was tested with the same protocol. A time-
line of the campaigns is shown in Figure A.1.
In order to understand which performance dier-
ences appear due to lack or reduced frequency of train-
ing during a mission, each crew was split in two groups:
frequent and infrequent yers (FF and IF, respectively).
The FF group would perform all the tests in the proto-
col every four weeks, whereas the IF group would still
perform basic experiments as frequently as the FF, but
wouldn’t be tested in the space-ight simulator only
in a twelve-weeks basis, as represented in Figure A.2.
The division of both groups was done after the train-
ing sessions, in order to balance the amount of pro-
cient and less-procient pilots in each group. The train-
ing phase took place during the Antarctic summer and
was performed by an instructor on site. It included 3
hours of instructed training and 6 hours of unsuper-
vised ight. After training completion, a check-ight
was performed by all the crew, which set the ocial
start of the experimental campaign.
Each session of the experiment was performed with
the same procedure, as shown in Figure 4. First, a set of
two ight scenarios was own (three at RF0, RF3, RF6
and RF9. See Figure A.2), which contained an instru-
mental ight, where the pilot could y with the support
of the docking instrumentation on the cockpit panels;
a visual ight, where the pilot could only rely on the
periscope view, and if doing a 3-ights session, an "ISS-
Pitch" scenario, where the target station was spinning
with a constant local angular rate of 2 deg/s. This last
scenario was meant to challenge the pilot under an un-
expected situation and required continuous correction
of the approach path. After the ight tests, two well-
known tests were performed, in order to assess both
the psychomotoric and the cognitive status of the sub-
ject. The Vienna Test System test battery "MLS - Motor
Performance Series" was used to test the motor skills
(see [14, 15]). Additionally, a mental cognition test with
the "Cognition" software battery was performed (see
Basner et al. [16]). Finally, two questionnaires were
handled to the participants: the Pittsburgh Sleep Qual-
ity Index (PSQI) and the State-Trait Anxiety Inventory
(STAI). The results obtained from the described tests
are not in the scope of this paper and should be later
clustered with the ight performance results, in order
to nd correlations between the mentioned measure-
ment systems.
Simulator Flig hts Vienna Test
System (VTS) Cognition Questionn aires
Instrumental Vis ual ISS Pitch
(every 3 sessi ons)
Flight Scenarios
Figure 4: Session’s testing procedure.
2.2.1. The Soyuz-TMA simulator
At the Institute of Space Systems of the University of
Stuttgart, a Soyuz-TMA spacecraft simulator has been
used for training and research during the last decade
(see Noll et al. [17]). Dierent ight phases have been
under focus, most especially the close-range approach
and docking to the Russian segment of the ISS. The
spacecraft docking simulator, a self developed set-up
with a core based on the Orbiter Spaceight Simula-
tor (Schweiger [18]) is capable of recreating a realis-
tic docking manoeuvre and requires a high level of
skill performance from the pilot, who needs to con-
trol a 6 degrees-of-freedom spacecraft while monitor-
ing other ight parameters displayed in the featured
cockpit. The simulator’s hardware is a simplied ver-
sion of the real Soyuz cockpit, but it features the main
and necessary controls and systems that are needed to
perform a rendezvous and docking procedure (propul-
sion, radar, communications,...). The limited space and
weight to be shipped to Antarctica lead to the design
of an adapted one-seater simulator, which nevertheless
provided the same features for the pilot, as seen in Fig-
ure 5.
The ight procedure is represented in Figure B.1, as
it shows a typical ight prole for an approach tra-
jectory with the Soyuz-TMA spacecraft to one of the
four Russian docking ports of the ISS (Zvezda, Pirs,
Poisk, Rassvet). This procedure is a simplied trajec-
tory which doesn’t consider far-range staging points,
as the ight duration would be too long.
The ights to be performed during the experiment
were divided in a set of pre-dened scenarios, to en-
hance comparability. Table 3 describes how the scenar-
ios were distributed during the campaign. The ight
data was recorded and saved for posterior analysis. No
feedback on ight performance was given in real-time
but the parameters provided by the simulator’s instru-
mentation. As explained in Bosch Bruguera et al. [19],
a ight analysis methodology has been developed in
order to process the raw parameters obtained from the
simulator. Such parameters were lineal and angular o-
sets to the relative target docking port, lineal and angu-
lar rotation rates of the spacecraft, fuel status and con-
trol inputs in each axis. More signicant parameters
regarding a certain ight phase, such as lateral oset
to the ideal trajectory, amount of inputs, among oth-
ers, were calculated out of the raw parameters recorded
every simulation time-step (0.2 s). See Table C.1 for a
description of the recorded and processed ight param-
The pilots had to follow a previously learned proce-
dure by performing the ight phases shown below:
Systems activation
Final approach (FA)
A detailed description of the phases can be found in
Appendix B and in Bosch Bruguera et al. [19].
2.3. Statistical Analyses
A total of 1298 ights have been performed through-
out the experiment. In order to facilitate the assessment
of piltoing performance, the obtained ight parame-
ters and post-processed data, as shown in Appendix C,
have been analysed, rst, by visualizing trends, ight
trajectories and, posteriorly, by means of linear mixed-
eects models (LME). Such mathematical models oer
the possibility to correlate a predictor variable to mul-
tiple xed and random eects, as explained by Bates et
al.[20] and the UCLA [21]. In this case, LME models al-
low to correlate which experiment factors have played
a bigger role in the evolution of the ight performance
of the pilots. The presented models focus on the ef-
fect of the main grouping variables Campaign, Group,
Flight Type, Session ID and Pilot, which should show
how the application of the same experimental proto-
col in dierent conditions leads to signicant ight per-
formance dierences. Figure 6 depicts how the experi-
ment grouping variables are linked to each other. Note
that each pilot belongs to a specic group (FF or IF), and
this group is directly linked to a Campaign. Such rela-
tion is considered as "nested", as will be shown when
implementing the model.
The LME models run to analyse the ight data have
been assessed by performing ANOVA comparisons,
which showed in which extent a model provided better
predictions. The analysis of the models has been car-
ried out with the use of the lme4 package for R by Bates
et al. [22] and the data has been processed with help
of the R package sjPlot by Lüdecke [23]. Additionally,
the odds ratios for ight success haven been estimated
by means of Generalized LME (GLME) using a bino-
mial function, which allows to understand which are
the probabilities of mission failure. The odd ratio rep-
resents the ratio between successful and failed ights.
Hence, a higher value is desired for the best reliabil-
ity. Further detail on the statistical analysis is available
upon request.
3. Results
3.1. Flight Trajectories
A useful tool to understand how pilots performed is
to plot the ight trajectories of each ight according
to the scenario own. Figure 7, Figure 8 and Figure 9
show the ight trajectories of all the own scenarios
in the SIMSKILL experiment. Note how the the tra-
jectory distribution diers between scenarios. Instru-
mental scenarios are own with much higher reliabil-
ity, as most of the pilots aligned to the center of the
approach corridor with better accuracy. Moreover, the
approach speed was monitored and adapted with ex-
actitude, causing a rainbow-coloured alignment path
since the majority of pilots kept the required speed.
It is however important to remark that a considerable
amount of pilots accelerated towards the ISS before en-
tering the safety zone dened by the virtual corridor, as
seen by the more diagonal trajectories.
The visual ights shown in Figure 8 present a rather
dispersed distribution, both in terms of alignment and
Left MFD Right MFDPeriscope
Computer (Main)
Figure 5: Overview of the mobile Soyuz-TMA simulator. MFD: Multi-Functional Display. RHC and LHC: Right and Left Hand Controllers.
Scenarios Frequency Initial conditions Description
P os[m]; ˙
P os[m/s]; ~
Ang[º]; ˙
Ang [º/s]
Instrumental Every session (68.201,5.211,-12.670); (-0.033,-
0.008,0.0140); (34.734,8.777,-3.623);
Use of docking instrumentation al-
Visual Every session (69.741, 17.865,5.055); (0.030,-
0.058,0.004); (-47.131,-2.866,-13.283);
Only use of periscope view.
ISS-Pitch Every 3 sess. (79.797,-24.279,3.517); (-0.063,-
0.146,-0.015); (-0.141,-2.458,21.337);
Use of instrumentation limited to ap-
proach velocity monitoring. Addi-
tional diculty due to ISS pitch rota-
tion rate.
Table 3: Scenario description
Of f : Relative position to target’s port (Long., Vert., Horiz.).
Ang: Relative angle to target’s port main axis (Roll, Yaw, Pitch).
approach velocity. Note how some of the trajectories
are still outside the approach corridor within the last
meters to contact the station.
Finally, the ISS-Pitch scenario is depicted in Figure
9. The use of the instrumentation enhanced the capa-
bility of the pilots to align correctly inside the corridor,
although with less precision to the rst scenario. The
fact that the target station rotated continuously proves
how some trajectories permanently oscillate, even tres-
passing the corridor’s limits.
3.2. Performance Assessment
The grouping variables Campaign, Group, Session
ID, Flight Type and Pilots presented in section 2.3
have been implemented as factors for the analysis
of three performance-relevant parameters: Alignment
time, amount of Steering errors and, nally, the amount
of unsuccessful ights. The data trends have been
visualized by using a combination of box-plots (see
MATLAB "boxplot"[24]), histograms and, later, anal-
ysed with LME and GLME models.
3.2.1. Training Frequency - Pilot Groups
A dierence on ight performance between frequent
and infrequent yers is expected in the later months
after the rst checkight (RF0). Figure 10 shows how
the percentage of failed ights in all the scientic cam-
paigns decreases clearly for FF pilots: initially, approx-
imately a 12% of the performed ights couldn’t be
docked to the target docking port. A much lower per-
Instrumental ISS-Pitch
Stugart 2016 Halley VI 2015 Halley VI 2016 Concordia 2018 Concordia 2019
Frequent Flyers
Infrequent Flyers
Only on RF0,3,6,9
Flight Scenario
Figure 6: Representation of the relation between the experiment grouping variables.
centage of unsuccessful ights happens for the IF group
in the session RF0. The initial dierence between FF
and IF is caused by a singular pilot in one of Halley
VI campaigns. The use of a Generalized Linear Mixed-
Eects binomial model allows to integrate the eects
of singular pilots as random variables and obtain pre-
ciser estimations on how the risk of mission failure
should evolve, according to the data recorded. The ob-
tained model results prove that the odds-ratio of mis-
sion success for frequent yer pilots is higher on all
subsequent ight sessions, with an estimate value rang-
ing from 35,02 (p<.001, condence interval 95%) up to
59,50 (p<.001) on the last experiment’s session RF9. On
the other hand, the infrequent yer group starts very
reliably, but decreases its performance already at the
next session RF3, with a value of 14,82 (p<.001). On RF6
and RF9 the reliability slightly improves, ending with a
value of 29,16 (p<.001).
The eects of interrupted training frequency can
also be assessed by observing the duration of the Sys-
tems Activation phase or "Alignment Start" in this doc-
ument. This can be observed more especially in the in-
strumental scenarios of each session, since they are run
rst. As seen in Figure 11, the time that pilots required
for activating the spacecraft prior to alignment and ap-
proach is clearly aected by the training frequency.
The rst check-ight (instrumental, RF0) shows very
similar times with a median of approximately 36 sec-
onds (p<.001), whereas the later sessions tend to show
an increase of time required by IF pilots up to 70 sec-
onds (p<.001). Instead, FF pilots take more time until
session RF3, but improve their systems activation dura-
tion and keep it constant to a value of about 40 seconds
during the whole experiment.
The amount of steering input errors that happen in
each ight has been evaluated along the experiment
time-line, as shown in Figure 12. Note how frequent
yer pilots do more errors during the RF3, RF6 and
RF9 sessions, which include the more dicult scenario
"ISS-Pitch". The presented data has been analysed by
means of an LME that takes into consideration Cam-
paign, Group and Pilots as nested random eects, plus
an additional random eect on the intersect for the
Flight Type. The dierences between FF and IF groups
have proven to be statistically signicant at the level of
Figure 7: Flight Trajectories on the Instrumental Scenario. Flight samples: 406.
Figure 8: Flight Trajectories on the Visual Scenario. Flight samples: 377.
3.3. Environmental conditions: Isolation, Connement
and Hypoxia - Campaigns
In order to understand how piloting performance
and reliability are aected by factors such as isola-
tion, connement or hypoxia, a comparison between
the campaigns in Concordia, Halley VI and Stuttgart
needs to be done. Figure 13 displays the distribu-
tion of amount of steering input errors for each cam-
paign. The black boxes representing the groups of fre-
quent yers show how each of the campaigns kept an
amount of approximately 25 to 30 errors. However,
the blue boxes representing the infrequent yers pi-
lots group are placed at higher values, diering de-
pending on which campaign. Note that the Concordia
campaigns show a higher dierence between FF and
IF. In Halley VI, the dierence between both groups
still exists, whereas in Stuttgart both groups deliver
the same amount of errors. The only campaign that
presents statistically signicant dierences is Concor-
dia 2018 (p<.05), with an estimate of 56 input errors per
Figure 9: Flight Trajectories on the ISS Pitch Scenario. Flight sam-
ples: 267.
The systems activation phase has been also com-
puted in order to compare which role could the ex-
perimental environment play, that is, the campaign.
As seen in Figure 14 . A statistical signicance has
been found out in the IF group of Concordia 2018 (90
s, p<.05) and the results of Stuttgart 2016 are also real-
itvely signicant with p=0.152. See how the frequent
yer groups deliver a similar value for all campaigns,
while the Antarctic campaigns have shown to lead to a
longer Alignment Start duration for infrequent yers.
An extended analysis of the ight data described in
Appendix C has not been considered in the scope of
this paper and are expected to be analysed in further
4. Discussion
4.1. Training frequency
The presented results show how training periodicity
is a key factor to ensure piloting reliability, as an activ-
ity that requires high concentration and psycho-motor
skills. As proven by Salnitski et al. in previous ISS and
Mir missions, a three-month period of training causes
a critical decay of skills and endangers mission success.
SIMSKILL conrms such a statement by providing a de-
tailed comparison by FF and IF pilots, where dierences
between both groups are signicant in later phases of
isolation. It is important to note that studied param-
eters have shown substantial dierences between fre-
quent yers and infrequent yer groups. In the rst
case, a contstant performance has been delivered by
most of the subjects, although an initial degradation
happened from phases RF0 to RF3. One of the reasons
for that behaviour can be explained by the sudden in-
terruption of training, since subjects had been trained
Session (RF)
Percentage of failed ights
Figure 10: Percentage of non-docked ights in each experimental
phase. Flight samples: 1298.
in a one to two day basis before performing the initial
check-ight (RF0). A test after one month was at rst
challenging, but then proved to stabilize throughout
the experiment. On the other hand, infrequent yers
were applied a three-month training frequency, show-
ing a clear decay of performance. Thus, the application
of training sessions with at maximum a month of dif-
ference ensures a constant piloting performance, even
an improvement in certain pilots. However, a longer
interruption of training leads to erratic piloting and sig-
nicantly reduces the mission success rate.
4.2. Isolation and Connement
Despite the existing individual dierences, a rst
assessment of the dierent crews and campaigns has
shown that isolation and connement, as well as hy-
poxia in Concordia, can be factors that increase the de-
cay of piloting performance as well of that of other
activities that require a high level of cognitive and
psycho-motor skills. The dierences in performance
between each campaign show that the crew-members
in Stuttgart delivered a more stable performance, both
FF and IF pilots, whereas in Antarctica, especially in
Concordia, the reliability of the pilots decreased sub-
stantially, as shown in Figure 13.
The so-called third quarter phenomenon (see Wil-
son [25]) has been assessed but no remarkable ndings
could be pointed out. Further analysis on that matter
will proceed after clustering the data from other tests.
Alignment Start [s]
Figure 11: Start of the alignment phase in instrumental ights. F light
samples: 490.
4.3. Hypoxia
The inuence of hypoxic conditions in Concordia
could be one of the performance degradation cataly-
sers. The higher values obtained in both Concordia
campaigns, compared to those of the Halley VI station
lead to consider the eects of hypoxia to skills degra-
dation, although the presented data is not conclusive,
as more factors need to be analysed in order to assure
the direct link of hypoxia to performance decay.
4.4. Additional factors
A multitude of extra variables play a big role on
the obtained results, mostly the personal dierences
between subjects. Age, qualication, gender, cultural
background, experience with gaming devices are pa-
rameters that dene how pilots performed. Some re-
sults have been found to be diering between crews,
which could imply a direct inuence of the training
procedure prior to session RF0. The eect of the train-
ing performed by a selected ight instructor can not be
underestimated, even if a very strict experimental ight
protocol had been designed. Finally, it is also important
to mention that besides the purely physical factors such
as hypoxia and isolation, the inter-personal relations
between each crew in Antarctica can be an additional
factor to be considered when analysing performance of
the crew. As an example, the already challenging con-
ditions that the Concordia Station poses to the crew
Total Input Errors
Figure 12: Total steering input errors per ight. Flight samples: 1298.
could be magnied by intra-cultural dierences in a
multinational environment.
4.5. Performance degradation countermeasures
In order to ensure mission success, it has been recog-
nized that training frequency is the main factor, since
frequent yers in all campaigns performed similarly.
As already seen in astronaut training, the denition
of standard training procedures as well as contingency
planning are crucial for the astronaut to evaluate and
solve any issues on board. A predened training rou-
tine is consequently essential.
The inuence of the hardware set-up can’t be ig-
nored, as piloting performance can vary strongly de-
pending on the human-computer-interfaces such as the
joysticks and displays. Therefore, a ight simulator
with a realistic astronaut cockpit position has been de-
5. Conclusions
The use of an adapted, but realistic Soyuz-TMA
spaceight simulator in Antarctica and in the Institute
of Space Systems of the University of Stuttgart has pro-
vided a big dataset that allows to understand how pi-
loting performance is aected by isolation and con-
nement, hypoxia and interrupted training periodicity.
An experimental protocol was dened accordingly, and
has allowed to gather a valuable dataset, not only from
Total Input Errors
Figure 13: Total steering errors on all campaigns. Flight samples:
the simulator ights, but also from additional testing
devices.Parameters such as the cockpit activation dura-
tion, the amount of steering errors showcase how hu-
man memory and precision decrease after long periods
without training, and should be further correlated to
the Cognition and Vienna Test System tests performed
in parallel.
The application of linear mixed-eects models for
the data analysis has proven to be a reliable tool when
it comes to assess parameters aected by multiple vari-
ables. The possibility to integrate random variables
into the model allows not to only t the model more
precisely, but to nd out which additional factors play
a bigger role in the variability of the data. In this
experiment’s case the skill dierences between pilots
have shown the biggest variance, which has inevitably
caused the appearance of non statistically signicant
The presented paper is an overview of the obtained
data from the recently completed SIMSKILL experi-
ment. Further results and an enhanced performance
analysis methodology are expected to give deeper de-
tail on which are the most critical factors for the deni-
tion of a reliable human long duration space mission.
Alignment Start [s]
Figure 14: Start of the Alignment phase for the last experimental
session, RF9. Flight samples: 67.
The current work is fruit of a wide range of partners
and participants. Thanks to the DLR and BMWi for
sponsoring the project. Acknowledgements to IPEV,
PNRA and BAS for their incalculable support on im-
plementing this experiment in both Concordia and Hal-
ley VI stations. Special thanks to the SciSpaceE Team
of the ESA for opening the possibility to perform sci-
ence in such a singular environment and coordinating
the many dierent participants. Finally and most im-
portantly, a big acknowledgement to all volunteer par-
ticipants of the SIMSKILL experiment as well as the
ESA Research Medical Doctors in Antarctica, who con-
tributed to this project during a whole campaign for the
sake of science and space research.
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Appendix A. Experiment Protocol
Halley VI
Brunt Ice Shelf
0 m AMSL
Dome C
3200 m AMSL
IRS Stuttgart
500 m AMSL
Figure A.1: Chronological representation of the ve dierent SIMSKILL Campaigns performed in Concordia, Halley VI and Stuttgart (control
group). AMSL - Above Mean Sea Level
12/12/2018 30/9/2019
Frequent Flyer
Frequent Flyer
Group Frequent+Infrequent
Flyer Groups
Frequent+ Infrequent
Flyer Groups
Initial Checkflights (RF0)
Initial Checkflights (RF0)
Final Checkflights (RF9)
Final Checkflights (RF9)
Figure A.2: Example of an experiment campaign. In this case, Concordia 2019. RF: Regular Flight
Appendix B. Flight Prole
20 m 0 m
safety corridor
Start of the
Figure B.1: Typical ight prole for the approach and docking procedure of the Soyuz spacecraft.
Phase Description and rules
Systems activation Start of the propulsion and docking systems: Activate Propulsion System’s valves and RCS;
Initiate docking instrumentation; Lock on to target docking port; Observe periscope and
plan a ight strategy.
Alignment Point spacecraft to target docking port. Keep zero approach velocity. Move laterally to
align with approach corridor. Avoid losing visibility in periscope.
Approach Once in approach corridor, approach is allowed. Fire THC forwards to the required ap-
proach speed. Correct attitude and alignment as needed. Reduce speed as distance to target
decreases. Monitor docking instrumentation if allowed.
Final Approach Once within the last 20 meters to target port, keep approach speed to 0,10 m/s. Do minimal
corrections and focus to the docking marker, if visibility is enough.
Table B.1: Flight Phases description
Appendix C. Flight Parameters
Each of the ight parameters shown in Table C.1 has been analysed for all three active ight phases (Alignment,
Approach and Final Approach (FA). Some parameters are provided with the average (AVG) and root mean square
(RMS) throughout a whole ight phase. Root Mean Square should provide a better insight to the variability of the
parameter during the time period, although not being able to show negative signs.
Parameter Units Description
Phase Start s Start time of the ight phase.
Phase Duration s Time elapsed between start and end of a phase.
Docking Time s Total time until docking contact.
Time out of corridor s Total time outside the approach corridor
Fuel spent kg Amount of propellant spent during a phase
Lateral Oset m Lateral oset from target’s docking port main axis, as a function of
Of fyand Offz, respective lateral osets on the target port’s local axes.
LatOf f =qOff 2
y+Of f 2
Time without visibility s Time of ight without direct periscope view to the target docking port.
Steering Inputs - Amount of steering inputs per phase for each axis of the RHC and LHC.
Steering Average Duration s Average duration of the steering inputs on each axis.
Steering Errors - Amount of steering errors on each phase.
Induced Errors - Amount of errors provoked on a joystick axis due to the input on another
axis of the same joystick.
Combined Joysticks - Number of times where both joysticks were actuated simultaneously.
Combined LHC Axes - Number of times where any of the LHC axes are activated simultane-
Combined LHC (YZ) Axes - Number of times combining axes Y and Z of the LHC.
Combined RHC Axes - Number of times where any of the RHC axes are activated simultane-
Combined RHC (YZ) Axes - Number of times combining axes Y and Z of the RHC.
Combined Time s Average time spent on each of the above combinations.
Lateral Oset AVG/RMS mLateral Oset calculated throughout a ight phase.
Approach Velocity AVG/RMS m/s Approach Speed calculated throughout a ight phase.
Lateral Velocity AVG/RMS m/s Lateral Velocity calculated throughout a ight phase.
Angle AVG/RMS ºPitch, Yaw and Roll calculated throughout a ight phase.
Angular Rate AVG/RMS º/s Pitch, Yaw and Roll rates calculated throughout a ight phase.
Fuel Spent on Error Inputs kg Amount of propellant spend for wrong inputs.
% Steering Errors - Percentage of steering error, in relation to the total amount.
% Fuel on Errors - Percentage of fuel spent on erratic steering inputs, in relation to the total
AVG fuel consumption kg/s Mass of fuel spent on average for the whole ight duration.
Table C.1: Flight parameters overview.
ResearchGate has not been able to resolve any citations for this publication.
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Manual piloting of manned spacecraft during its diverse flight phases has become progressively less frequent as automated systems achieve better reliability. Nevertheless, the assessment and maintenance of piloting skills is still a crucial part of manned space missions. As an example, the final approach phase of the Soyuz spacecraft to either the MIR or ISS space stations, due to technical irregularities, has been recurrently one of the most manually steered flight phases and has been proved as a challenging manoeuver for the spacecraft's commander. In the early phases of manned spaceflight, space agencies mainly resorted to the use of the flight instructors' subjective rating during simulator or airplane training. Nowadays, highly parametrized trainings can be analysed with higher detail to assess flight performance. Within the framework of the SIMSKILL experiment, which aims to investigate the effects of confinement and hypoxia for long term space missions in the Antarctica research stations Halley VI and Concordia, as well in Stuttgart, Germany, the Soyuz-TMA spaceflight simulator developed by the University of Stuttgart offers the possibility of training the docking procedures undertaken by the astronauts in a high fidelity simulation. Consequently, a flight evaluation methodology has been developed in order to analyse the flights performed by the participants in the simulator. The raw data obtained from the simulator (spacecraft speed, position, angles, joystick inputs i.a.) is processed by means of spacecraft dynamics and control algorithms and, subsequently, the flight performance can be assessed, providing a better insight on which are the critical parameters during each flight phase. With the use of statistical analysis, this evaluation method enhances the recognition of individual patterns, environmental influences such as isolation, hypoxia or lack of daylight, and weaknesses caused by different flight strategies undertaken by the pilots. This document describes the operating principles of the flight evaluation methodology, and gives a detailed description on the computational techniques used to process the flight data recorded from the experimental sessions undertaken both in Germany and the Antarctica. The use of such feature on simulator training procedures is therefore an interesting implementation, which offers additional feedback on flight performance besides personal advice from the instructors, enhancing the assessment of stressing mission phases.
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