Anthropometric Changes in Spaceflight

Objective This study aims to identify the change in anthropometric measurements during spaceflight due to microgravity exposure. Background Comprehensive and accurate anthropometric measurements are crucial to assess body shape and size changes in microgravity. However, only limited anthropometric data have been available from the astronauts in spaceflight. Methods A new photogrammetry-based technique in combination with a tape-measure method was used for anthropometric measurements from nine crewmembers on the International Space Station. Measurements included circumference and height for body segments (chest, waist, bicep, thigh, calf). The time-dependent variations were also assessed across pre-, in-, and postflight conditions. Results Stature showed a biphasic change with up to 3% increase at the early flight phase, followed by a steady phase during the remaining flight. Postflight measurements returned to a similar level of the preflight. Other linear measurements, including acromion height, showed similar trends. The chest, hip, thigh, and calf circumferences show overall decrease during the flight up to 11%, then returned close to the preflight measurement at postflight. Conclusion The measurements from this study provide critical information for the spacesuit and hardware design. The ground-based assessments for spacesuit fit needs to be revalidated and adjusted for in-flight extravehicular activities from this data. Application These data can be useful for space suit design as well as habitat, vehicle, and additional microgravity activities such as exercise, where the body shape changes can affect fit, performance, and human factors of the overall design.

Space suit concerns make US moon landing delay likely

Headline UNITED STATES: NASA moon project will face delays

The importance of lunar dust mitigation during future human led lunar missions

<p>With the Artemis mission set to launch in 2024, returning humans to the lunar surface for the first time in over half a century, it is imperative to ensure human health and safety on a variety of fronts. Lunar dust exposure is one of many areas of concern regarding astronaut health and safety. During the Apollo missions it was reported that lunar dust was a nuisance and induced allergic-like symptoms upon exposure. In addition, it was also reported that instruments became coated with dust that was difficult to remove, and that the dust adhered to everything and tore through space suit fabric. Numerous inhalation studies have determined that lunar dust is more toxic than analogous terrestrial materials but less so than silica dust. Apollo dust mitigation systems were successful on some missions but failed on others. As humans are to stay on the lunar surface for extended periods relative to the Apollo missions, it is vital to fabricate instruments that would address the lunar dust problem with greater reliability. There must be multiple steps to remove all lunar dust, including the ultra-fine <10 µm fraction which was the most difficult dust size to remove. There must be multiple steps regarding lunar dust removal including a chamber to remove dust and de-suit, and a vacuum with high level HEPA filtration to remove dust. The first chamber would be to filter out any dust that comes into the module from the outside. Once all the air is clear, then the next step would be to remove any remaining dust on the suits using a hand-held vacuum with a HEPA H14 filter which only allows up to a maximum 0.005% of particles 100 nm in size to pass through the filter. Then, it would be safe to de-suit. It would be wise to have a second chamber between the first chamber and the command center of the lunar module that would vacuum any remaining dust before opening to the main command chamber. Ultra-high quality HEPA filters of both the chamber and hand-held vacuum systems should be replaced frequently to maintain optimal dust mitigation. Investing time and resources into lunar dust mitigation should be a top priority for the upcoming Artemis mission to avoid the issues encountered on the Apollo missions.</p>

Propellant Off-Gassing and Implications for Triage and Rescue

INTRODUCTION: Hypergolic propellants can be released in large amounts during space launch contingencies. Whether propellant-contaminated suit fabric poses a significant risk to rescue crews, due to off-gassing, has not been explored in detail. In this study, we addressed this issue experimentally, exposing space suit fabric to propellants (dinitrogen tetroxide [N2O4] and monomethyl hydrazine [MMH]).METHODS: The NASA Space Shuttle Program Advanced Crew Escape System II (ACES II) is similar to the NASA Orion Crew Survival System (OCSS) and was utilized here. Suit fabric was placed and sealed into permeation cells. Fabric exterior surface was exposed to constant concentrated hypergolics, simulating permeation and leakage. Fabric was rinsed, and permeation and off-gassing kinetics were measured. Experimental parameters were selected, simulating suited flight crewmembers during an evacuation transport without cabin air flow.RESULTS: The fabric allows for immediate permeation of liquid or vaporized MMH and N2O4. NO2 off-gassing never exceeded the AEGL-1 8-h level (acute exposure guideline level). In contrast, MMH off-gassing levels culminated in peak levels, approaching AEGL-2 10-min levels, paralleling the drying process of the fabric layers. DISCUSSION: Our findings demonstrate that MMH off-gassing is promoted by the drying of suit material in a delayed fashion, resulting in MMH concentrations having the potential for adverse health effects for flight and rescue crews. This indicates that shorter decontamination times could be implemented, provided that suit material is either kept moist to prevent off-gassing or removed prior to medical evacuation. Additional studies using OCSS or commercial crew suits might be needed in the future.Schwertz H, Roth LA, Woodard D. Propellant off-gassing and implications for triage and rescue. Aerosp Med Hum Perform. 2020; 91(12):956961.

Evaluating Lumbar Shape Deformation With Fabric Strain Sensors

Objective To better study human motion inside the space suit and suit-related contact, a multifactor statistical model was developed to predict torso body shape changes and lumbar motion during suited movement by using fabric strain sensors that are placed on the body. Background Physical interactions within pressurized space suits can pose an injury risk for astronauts during extravehicular activity (EVA). In particular, poor suit fit can result in an injury due to reduced performance capabilities and excessive body contact within the suit during movement. A wearable solution is needed to measure body motion inside the space suit. Methods An array of flexible strain sensors was attached to the body of 12 male study participants. The participants performed specific static lumbar postures while 3D body scans and sensor measurements were collected. A model was created to predict the body shape as a function of sensor signal and the accuracy was evaluated using holdout cross-validation. Results Predictions from the torso shape model had an average root mean square error (RMSE) of 2.02 cm. Subtle soft tissue deformations such as skin folding and bulges were accurately replicated in the shape prediction. Differences in posture type did not affect the prediction error. Conclusion This method provides a useful tool for suited testing and the information gained will drive the development of injury countermeasures and improve suit fit assessments. Application In addition to space suit design applications, this technique can provide a lightweight and wearable system to perform ergonomic evaluations in field assessments.

The Model A-7LB Space Suit

This chapter outlines the features of the advanced model A-7LB space suit (or Omega suit) and discusses the various Apollo missions this model suit was flown aboard.

Developing the State-of-the-Art Space Suit

What is the definition of a space suit? This chapter explains and chronicles the development of the model XMC2-ILC pressure suit for the early U.S. Air Force high-altitude aircraft.