Motivation: Why Artificial Gravity? Current countermeasures are not sufficient to prevent the detri m ent a l physiologi cal ef fects of long- d urati o n s p ace fli g ht Types of Artificial Gravity h ttp ://p er m a n e n t .co m /sp - etst a. h t m l The Potential New R x ? “Spin in the Gym” ? “Prescribed AG Dosage” ? “AG Sleeper” Intermittent Short-Radius Centrifugation ? Cost-effective ? Space-ef ficient ? Relatively easy to implement ? Fits w i thin ISS/Spacehab Intermittent Short-Radius Centrifugation Out-of-plane head movements d u ring rotation produce sensory conf lict vestibular vs. visual and kinest hetic – Inappropriate non-compensatory n ystagmus – Motion sickness – Illusory tilt sensations – Postural instability Artificial Gravity Level Tradeoff 30 0 5 10 15 20 25 30 35 40 45 50 55 Radius (in m) 4- m a n Ehrick e 8- m a n Von Br aun PG Kr am e r & B y e r s 1.0g 0. 277 g Schnit z er MIT Di am andis Major Features of Rotating Environment Artificial Gravity Level (Centripetal Accel.) r ωωωω 2 Cori olis Forces -2 m ( ωωωω x v ) Gravi ty Gradien t s h/r Cross- coupled Angul a r Accelerati o ns ωωωω SRC x ωωωω Head Stimul us Schematic of MVL Short-Radius Centrifuge mo t o r lights t a c h o m et er r e ducer co unt erweigh t belt pitch dial slip ring 1. 9 m head r e st ca m e ra foot plate eye dat a ti m e r 0:10:25 co nt roll er TV TV for cam era VCR VCR w i rele ss hear t rat e m o n ito r MIT Short-Radius Centrifuge ? 2 meter radius platform ? Variable ro tation ra te ? 100 % gravity gradient along lon g itudinal b o dy axis Hypothetical Canals Right Ear Do wn Position (RED) Nose Up Position (NU) Roll Ca nal Pitch Canal Pitch Canal Roll Ca nal Response of the cupula 90 degree yaw head turn on a 23 rpm centrifuge from the “right ear down” to “nose up” position Base d on Y o u n g - Oma n L a p l a ce t r an sf er f u n c t i o n mo del Semicircular Canal: Cupula Dynamics 0 5 10 15 20 25 30 35 40 -0 . 5 0 0.5 1 1.5 2 2.5 Roll Canal 0 2 4 6 8 10 12 14 16 18 -0 . 5 0 0. 5 1 1. 5 2 2. 5 3 3. 5 Yaw Canal 0 5 10 15 20 25 30 35 40 -2 . 5 -2 -1 . 5 -1 -0 . 5 0 0. 5 1 1. 5 2 2. 5 Pitch Canal E xperimental findings (MVL 2000) – Head movements during short-radius centrifugation have disturbing side-effects, not all of w h ich can be predicted by a semicircular canal model – All side effects are subject to partial adaptation – Generaliz a tion of adaptation to different head- movements and to different rotating environments remain to be investigated – Short-radius centrifugation is a most promising stepping stone to stay healthy on the way to Mar s