Sahda Haroon conducting an EVA at SAM, Biosphere 2

All Extra-Vehicular Activities (EVAs) at SAM are conducted in pressure suits (“space suits”) designed and built by Smith Aerospace Garments. The air is delivered from the SAM Test Module by means of an oil-free compressor, gas transfer manifold, and umbilical line.

At the start of the EVA, one SAM crew members enters the SAM airlock. The crew seal the interior hatch. The crew member in the airlock opens a valve that releases the interior pressure until it equals that of the exterior ambient. When the Magnehelic pressure gauge reads zero, the crew member opens the exterior airlock hatch and welcomes Trent inside. The rest of the SAM facility remains pressurized.

Trent then assists with the donning (putting on) of the pressure suit, while another SAM staff member (Matthias Beach) runs the 100′ umbilical from the gas manifold to the airlock where Trent attaches it to the pressure suit helmet. Radio communication with the crew inside of SAM engages the air compressor, confirmation of adequate gas flow, and the helmet is secured to the suit.

The suited crew member confirms both sending and receiving radio communications inside the suit using a push-to-talk function. At this time, the crew member is on his or her EVA and walks from the airlock landing down to the Mars yard. The SAM staff are present for the entire EVA, standing by to assist. This is the ONLY part of the SAM analog experience in which the SAM staff are directly engaged due to the inherent dangers involved in breathing through an umbilical, physical exhaustion, and potential falls when wearing a pressurized suit.

In the summer Arizona days, EVAs are conducted after 8 pm or before 6 am to avoid excess heat, as the interior bladder traps the energy generated by the human body, and heats up quickly. While cooling garments do work to reduce discomfort, these late and early hours give the crew the most flexibility in form and function.

Once the EVA is complete, the crew member returns to the airlock, doffs (takes off) the suit with the assistance of Trent, and the airlock is again pressurized such that the crew member may return to the interior of the SAM pressure vessel.

We are honored to have engaged Dr. Cameron Smith, professor of archaeology and anthropology at Portland State University and founder of Smith Aerospace Garments for the design and fabrication of two fully functional pressure suits for SAM.

In February of 2021 Dr. Smith brought a field prototype to SAM for our first pressure suit test with Biosphere 2 Deputy Director John Adams inside. We then contracted Smith Aerospace Garments to design and fabricate a next generation EVA suit for use by crew members in the SAM Mars yard.