A    Large    Human    Centrifuge    for    Exploitation    and    Exploration Research The   Human   Hypergravity   Habitat ,   H 3 ,   is   a   large,   ground   based,   rotating   platform   which   can house   human   subjects   for   periods   of   weeks   to   months   while   exposing   them   24/7   to   higher than   normal   gravity   levels.   The   dimensions   of   the   system   are   such   that   a   crew   of   at   least   8 persons   can   live,   work   and   leisure   in   the   closed   habitat   as   if   they   would   be   living   on   a   planet with higher than Earth’s 1 g. Long-duration   stay   in   microgravity   on   the   various   space   stations   demonstrated   how   gravity, or   the   lack   thereof,   has   an   impact   on   many   aspects   of   human   physiology:   loss   of   calcium from   the   bones,   suppression   of   the   immune   system,   reduced   cardiac   capacity   and   many other   changes   as   if   the   subjects   were   ageing   prematurely.   Hypergravity   research,   on   the other   hand,   has   shown   in   animal   studies   the   reverse   line   an   increased   bone   density   and loss   of   fat   mass.   This   inspired   the   idea   that   this   hyper-g   environment   may   be   useful   for research   into   countermeasures   for   modern-day   health   issues   like   obesity   and   osteoporosis in   our   ageing   population.   Another   spin-off   and   valorization   for   the   H 3    may   be   found   in   top sports,    where    training    in    this    environment    may    lead    to    increased    muscle    and    maybe cardiovascular   performance.   It   would   also   be   interesting   to   explore   the   possible   benefits   of long   duration   hypergravity   to   support   high   speed   aircraft   pilots   to   withstand   high   g-load maneuvers. Since   the   H 3    will   house   at   least   8   persons   for   periods   of   weeks   or   months   in   a   closed environment,   the   facility   is   a   suitable   test-bed   for   group   psychology   and   operations.   This closed   environment   with   the   need   to   support   human   life   also   provides   the   opportunity   to   test (biological)   life   support   systems   that   are   required   for   long   missions   to   Mars   or   on-surface systems    foreseen    for    the    Moon.   A    number    of    studies    imply    the    use    of    large    rotating spacecraft   when   going   on   long   duration   missions   like   to   Mars.   However,   very   little   is   known about   the   human   response   of   long   duration   rotation   in   large   diameter   systems.   The   H 3 ,   with a   projected   diameter   of   175   meter,   would   be   an   ideal   platform   to   explore   the   applicability   of such future spacecraft. The   H 3    cannot   only   be   used   to   explore   the   effects   of   moderate   hypergravity   (max.   2g)   but, also   that   of   lowered   gravity,   i.e .   when   the   rotation   is   stopped.   From   that   moment   on   the body   has   to   adapt   to   a   relatively   lower   g-level.   The   type   and   direction   of   physiological adaptations   will   be   similar   to   those   when   going   into   microgravity,   although   with   an   expected reduced amplitude. Finally,   when   the   H 3    is   built   as   a   disk-shape   structure   it   should   be   explored   to   use   the   facility as a very large Coriolis platform for atmospheric and oceanic mass transfer research. The   H 3    concept   has   emerged   from   a   Topical   Team   (TT)   study   supported   by   the   European Space   Agency,    ESA ,    where,    over    time    a    group    more    than    70    persons    have    become involved.   They   cover   disciplines   as   human   physiology   and   psychology,   engineering,   sports, public   outreach   /   education,   life   support,   operations   as   well   as   the   representatives   of   various European science organizations. Overview    of    both    Ground-Based    (spin-off)    and    Space    Exploration    (spin-in)    related application   areas   for   the   H 3 .   For   ground   based   these   are:   basic   research   in   gravitational physiology,   platform   for   contemporary   diseases   and   ageing,   valorization   for   athletics   and training   and   as   Coriolis   platform.   For   Space   Exploration   spin-in   one   can   use   the   H 3    for research    related    to    large    rotating    spacecraft,    gravity    transitions,    the    reduced    gravity paradigm,   group   psychology,   habitat   and   life   support   systems   research.   For   both   Ground Based   and   Exploration   oriented   activities   the   H 3    can   be   used   for   education   and   outreach programs. References: 1:   White   paper   after   "Artificial   Gravity   Workshop".   Chairs:   William   Paloski   and   John   B. Charles.   Ames   Research   Center,   February   19–20,   2014.   NASA   2014   NASA   NASA/TM- 2014-217394 . 2:   A   large   human   centrifuge   for   exploration   and   exploitation   research.   J.J.W.A.   van   Loon   et al. Annales Kinesiologiae ,  3,1, p. 107-121, 2012 3:   The   large   Radius   Human   Centrifuge   'A   Human   Hypergravity   Habitat,   H3.   Jack   J.W.A.   van Loon,   Floris   Wuyts,   et   al.   Paper   IAC-09.A1.2.3 ,    60th   IAC   Congress.   Deageon,   South-Korea, 12-16 Oct. 2009. 3:   Study   on   Artificial   gravity   research   to   enable   human   space   exploration.   Edit   L.   Young,   K. Yajima and W. Paloski. I nternational Academy of Astronautics   (IAA), Sept. 2009. 4:   The   Human   Centrifuge.   J.J.W.A.   van   Loon.   Microgravity   Sci.   Technol.   21   (1-2):203-207, 2009. Countries involved during this study phase of H 3 : Austria,    Belgium,    Canada,    Denmark,    France,    Germany,    Ireland,    Italy,    Japan,    Slovenia, Sweden, Switzerland, United Kingdom, United States, The Netherlands. Next Steps From   the   Topical   Team   study   we   gained   quite   a   good   insight   on   potential   for   the   various applications   of   such   an   H 3    facility   both   in   health   and   space. As   a   next   step   towards   actually achieving   the   realization   of   this   H 3    large   and   unique   rotating   system   is   that   we   need   set clear   and   detailed   user   requirements   for   an   H 3    infrastructure,   using   a   bottom-up   approach involving   scientists   from   different   disciplines,   sectors   and   countries,   and   define   the   minimum radius   for   the   H 3    facility   based   on   a   series   of   vestibular   tests.   These   requirements   will   be combined   and   form   the   basis   of   a   conceptual   engineering   design   and   cost   estimates   of   the H 3    facility.   Based   on   interests   and   an   analysis   of   other   research   infrastructures,   a   market analysis   of   the   envisioned   H 3    facility   would   also   help   to   identify   its   use.   Since   we   foresee   to have   the   H 3    as   a   large   and   international   research   infrastructure   we   also   need   to   address   a suitable   governance   structure   and   potential   for   funding   and   a   communication   plan   to   inform the   science   and   technology   community   and   various   other   stakeholder   that   can   make   use   of such   a   unique   and   novel   facility.   All   these   points   will   be   addressed   in   a   study   that   we proposed   for   the   European   Commission    via   grant   on   Large   Research   Infrastructures    by   a group    of    some    80    scientists    and    engineers    from    Europe,    USA,    Japan,    Canada    and Australia,   as   well   as   a   group   of   European   and   international   science   organizations:   European College   of   Sport   Science   ( ECSS ),   Federation   of   European   Nutrition   Societies   ( FENS ), European   Society   of   Movement   Analysis   in   Adults   and   Children   ( ESMAC ),   European   Low Gravity   Research   Association   ( ELGRA ),   European   Society   for   Muscle   Research   ( ESMR ), European   Association   for   the   Study   of   Obesity   ( EASO ),   European   Association   of   Social Psychology    ( EASP )    and    the    International    Society    for    Gravitational    Physiology    ( ISGP ), supporting   a   project   team   by   VU-University    in   Amsterdam   (NL),   Iv-Consult ,   Papendrecht (NL),    University    of    Minho     (PT),    Cimolai ,    Porcia    (IT),    Let’s    Involve ,    Copenhagen    (DN), European    Science    Foundation     (ESF),    TNO    Soesterberg    (NL),    Strasbourg    (FR),    and      Liquifer Systems Group , Vienna (AT).

Historic Concepts Rotating space stations have been proposed starting with the pioneering work of the Russion visionnaire Konstantin  Tsiolkovskiy in the very early years of the 20 th  century. Tsiolkovskiy proposed a rotating space system including trees and humans. Later, in 1928, the Kroatien Herman(n) Potočnik (also known as Hermann Noordung) published a work with his rotating concept. Nordungs’ rotating spacecraft. One of the best known rotating space station is most likely the von Braun donut as presented in the early 1950 th . In this concept whole cities, lakes and forests were to be included in this rotating space craft. von Braun’s rotating space station One of the more recent studies regarding rotating spacecraft is a the NASA Fire Baton concept. With such a system one can apply artificial gravity during a trip to Mars in order to mittigate or even eliminate the compromizing effects of microgravity (near weightlessness) during the voyage. the NASA Fire Baton spacecraft. Although engineering concepts have been developed, it is still not clear how a human being would behave in such large rotating platforms for long periods of time. Also, we do not know what gravity level would be sufficient when going to e.g. Mars. This is where the H3 concept might shed some light. Future Prospects From paired controlled long duration animal studies where e.g. rodents, hamster, rat, guinea pig, and rabbit or chicken have been exposed to long duration chronic accelerations we know that fat mass decreases while bone density and cardiac capacity increases. Such observations deserve appropriate chronic hypergravity studies to see how these effects translate to humans. On the other hand it has been shown that human stem cells exposed to simulated microgravity are driven towards adipocytes compared to 1g controls while astronauts exposed to weightlessness for more than weeks show increased blood glucose and insulin concentrations suggesting insulin resistance. Obesity, contemporaty disease in current society The impact of gravity on glucose and insulin metabolism and related fat mass and obesity, makes hypergravity an interesting paradigm to explore especially in light of observations of increased obesity and diabetes in present-day communities as a result of escalated inactive and sedentary behavior in (mainly) the western society. Research using human chronic hypergravity, as foreseen for the H3 facility, will provide new insights to issues as insulin resistence and obesity.