How Spacesuit Architecture 'SmartSuit' Can Create Better Environment For Astronauts During Spacewalks

SmartSuit: It works on three key improvements to the current suit design, namely, increased mobility, enhanced safety, and informed interaction between the environment and the astronaut.

NASA astronaut Peggy Whitson during a spacewalk on Jan. 6, 2017. The Extravehicular Activity (EVA) was performed during Expedition 50 aboard the International Space Station. | Credit: NASA

New Delhi: More than 50 years back, humans walked on the Moon for the first time. Since then, several feats have been achieved in space exploration. Now, NASA plans to send humans to the Moon again, through the Artemis Mission. 

Therefore, researchers are trying to design spacesuits which are more advanced and create a more suitable environment for astronauts during spacewalks. 

Scientists at Texas A&M University in the United States are working on a new spacesuit architecture called 'SmartSuit'. According to the scientists, SmartSuit would create a safer and better spacesuit environment for Extravehicular Activity (EVA) on planetary surfaces.

The findings of their research were recently published in the journal npj Microgravity, Aerospace Medicine and Human Performance. 

What Is SmartSuit?

The SmartSuit is a spacesuit architecture which focuses on three key improvements to the current suit design, namely, increased mobility, enhanced safety, and informed interaction between the environment and the astronaut, according to the study. 

SmartSuit is proposed by Ana Diaz Artiles, one of the study authors. The researchers at Texas A&M recently collaborated with Robert Shephard, an associate professor at Cornell University, to develop prototypes of soft-robotics assistive actuators for the knee joints. An actuator is a device that produces a motion by converting energy and signals going into the system. The motion can be rotary or linear. 

How Are Current Spacesuits Designed?

In a statement issued by Texas A&M University, Diaz Artiles said that the current spacesuit has been designed for microgravity conditions. She explained that in these conditions, astronauts do not need to walk or move around using their lower body, they typically translate themselves using their upper body. 

Diaz Artiles added that when astronauts are on a planetary surface, they need to walk, bend, kneel, pick up rocks and many other similar activities that require better mobility in the lower body.

How Do Soft-Robotic Knee Prototypes Work?

According to the study, the soft-robotic knee prototypes work by using gas pressure to expand the internal chambers, so that they push against each other. 

As each internal chamber expands, the actuator bends. By using a soft material, the actuator forms to the human body. This creates a more comfortable fit and potentially reduces the risk of injury. 

Logan Kluis, the lead author of the study, said that soft robotics would allow the actuators to conform to the astronaut's body. This would greatly increase their comfort compared to more rigid hard surface actuators. 

The Robotic Actuators Reduce Metabolic Cost

Astronauts wearing the current spacesuit feel as though they are in a pressurised balloon. They need to fight against the suit, which is not only difficult, but also expends energy they will want to conserve when conducting EVA missions. According to the study, the energy spent moving against the suit contributes to the metabolic cost. The assistive robotic actuators are able to reduce the metabolic cost by 15 per cent, according to simulations specifically developed to investigate the effects of these actuators. 

Kluis said that a lot of energy is spent when astronauts are out collecting samples and doing tests. He said that when astronauts will be sent on missions to the Moon and Mars, they will either have to take all the food with them, or will have to grow it. Hence, any sort of savings one can have on energy will be very helpful, he added.

How Will A Full-Body Layer Help Astronauts?

The scientists' recent work focused on actuators for the knee joints. However, their ultimate object is to integrate actuators into a full-body layer. This will enhance motion in several body joints, according to the study. 

The full-body layer would press relatively hard against the astronaut, providing extra mechanical counterpressure (MCP), which increases mobility.

In the late 1950s, NASA and the United States Air Force had developed a mechanical counterpressure (MCP) suit which applied stable pressure against the skin by means of skintight elastic garments. It was developed again in the late 1960s, but the designs were never used.

Diaz Artiles said that pressure and mobility have an inverse relationship. The more pressure one has in a spacesuit, the lower the mobility. The less pressure an astronaut has, the easier it is to move around. 

The authors noted in the study that the pressure refers to the gas pressure the spacesuit provides to protect the wearer. The atmospheric pressure is about 14.7 pounds per square inch, and the current spacesuit provides a pressure of about 4.3 pounds per square inch, which pulses against the astronaut's body and contributes to the balloon effect. However, if a full-body soft-robotic layer could provide one pound per square inch, that would lower the amount needed for the suit to only 3.3 pounds per square inch. This means, there will be less pressure, and more mobility.

Kluis said that when one wears really tight under armour or really tight leggings, he or she feels additional pressure. The idea with the SmartSuit is that it would use both mechanical pressure and gas pressure. 

What Is Decompression Sickness?

Mechanical counterpressure can lower the risk of decompression sickness (DCS), which refers to injuries caused by rapid decrease in the pressure of air or water surrounding a person. It can also occur during unpressurised air travel. When an astronaut enters a lower pressure spacesuit, inert gas bubbles are formed in the human tissue. According to NASA, astronauts must take precautions to avoid decompression sickness that could occur when going on spacewalks. 

According to the study, decompression sickness can happen when the gas pressure surrounding a person decreases relatively fast, as a result of which the nitrogen in the body emerges as bubbles inside the body tissues. 

Breathing pure oxygen for up to four hours before conducting an EVA is the current solution to avoiding decompression sickness within the spacesuit. Through implementation of mechanical counterpressure, astronauts can spend less time on pre-breathe requirements, and more time on space exploration. Also, they will not have to worry about decompression sickness.

According to the statement, the researchers are still working on the SpaceSuit architecture. The actuator prototypes will help create a more accommodating and resourceful spacesuit for future planetary missions. 

The researchers' main aim is to create a spacesuit which will make astronauts feel that they are moving without a spacesuit.