Currently the impact load imparted to crewmembers landing in the Soyuz vehicle is unknown. This study is the first systematic assessment of the number and types of injuries associated with Soyuz landing. To date, we have found that nearly a third of United States Orbital Segment (USOS) crewmembers are experiencing injuries. Most of these injuries are minor, but they exceed expected rates based on analysis of seat accelerometer data from airborne and drop tests of the vehicle. The yet to be answered question is whether spaceflight deconditioning renders crewmembers more susceptible to landing impact injuries. Another possibility is that the Soyuz landing load is higher than our current estimates. It could also be that our analytical tools are insufficient to predict injury rates accurately for space vehicles. A final possibility is that some combination of these factors are responsible.

Current occupant protection requirements levied upon future NASA space vehicles are based, in part, on the mathematical prediction that minor injuries due to Soyuz landings have less than a 5% probability of occurrence. Understanding the risk of injury during Soyuz landings and the validity of current crew risk models will allow for improved crew protection in future spacecraft designs.

The following are the specific aims for this task:

Aim 1: This aim consists of data collection from two sources. One is flight medical records from a database maintained by the NASA Lifetime Surveillance of Astronaut Health (LSAH). This data is only obtainable for US astronauts. The other data source is from a survey that crewmembers are asked to complete. The survey requires an additional consent process.

Aim 2: The study team has not had success obtaining Soyuz seat acceleration data, and NASA management has abandoned any future effort of obtaining it. However, NASA is supporting a Small Business Innovation Research (SBIR) grant for the development of miniaturized accelerometers that can be worn by astronauts during dynamic phases of spaceflights. The conceptual design would allow the crew to adhere these sensors to locations such as the head or spine.

Aim 3: An analysis has been performed to identify the expected rates of Soyuz injury using the Brinkley model. These expected rates are compared with the actual injury rates uncovered by this study.