STS055-233-019 (26 April-6 May 1993) --- Terence T. (Tom) Henricks, STS-55 pilot, wears a special collar for a space adaptation experiment in the science module onboard the Earth-orbiting Space Shuttle Columbia. The Baroreflex (BA) experiment is designed to investigate the theory that light-headedness and a reduction in blood pressures upon standing after landing may arise because the normal reflex system regulating blood pressure behaves differently after having adapted to a microgravity environment. These space-based measurements of the baroreflex will be compared to ground measurements to determine if microgravity affects the reflex.
STS-55 Pilot Henricks with baroreflex collar in SL-D2 module onboard OV-102
STS055-22-004 (26 April-6 May 1993) --- Four of the seven crew members who spent 10 days aboard the Space Shuttle Columbia are pictured during a brief shift overlap period in the Spacelab D-2 Science Module. Left to right are Jerry L. Ross, Ulrich Walter, Bernard A. Harris, Jr. and Hans Schlegel. Ross, STS-55 payload commander, is changing a sample in a materials processing furnace; Walter, a German payload specialist is in the midst of a baroreflex test and fellow payload specialist Schlegel assists mission specialist and physician Harris with a physiological test at the "Anthrorack".
STS-55 crewmembers work in the SL-D2 module onboard OV-102
S85-26571 (Feb 1985) --- Wearing a special collar, Millie Hughes-Fulford, payload specialist, practices medical test operations scheduled for the Spacelab Life Sciences (SLS-1) mission. Robert Ward Phillips, backup payload specialist, looks on.  The collar, called the baroflex neck pressure chamber, is designed to stimulate the bioceptors in the carotid artery, one of the two main arteries that supply blood to the head.
SLS-1 crewmembers in high fidelity mockup of the Spacelab