NASA Suit Sensor Design

Problem

Problem Overview

Challenges in Astronaut Suit Design:

Astronauts frequently experience discomfort and injuries due to poor spacesuit interactions.

Many astronauts, due to their military backgrounds and competitive nature, tend not to report discomfort.

Impact of the Problem

The Human Cost of Space Exploration

Intense conditions during space missions can mask immediate sensations of discomfort and pain.

Delayed reporting leads to exacerbation of injuries, highlighting the need for more sensitive monitoring.

Current Methods and Limitations

Inadequate Solutions

Existing methods rely on post-mission reports and fail to capture precise or immediate data.

There's a significant lack of methods that effectively integrate objective and subjective data points.

Solutions

Innovative Approach

Precision Wearable Technology

Introduction of a wearable sensor array combined with a comprehensive survey.

Bridges the gap between objective data (like bruises) and subjective experiences (like verbal feedback).

Design & Development

Tailored Testing System

Components like sensor-embedded socks and modified boots specifically designed to detect pressures on critical areas like the dorsum of the foot.

Enhanced sensitivity to detect subtle discomfort during critical operations.

Potential & Scalability

Beyond Space – Broader Applications

Initially designed for space applications, with potential for use in sportswear and medical orthotics.

Represents a revolutionary step in the design of wearable equipment, emphasizing enhanced performance and comfort across various fields.

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Research

Understanding the Relationship Between Injury and a Written Survey

To make the project more tangible considering the limited time, we decided to focus on a specific component of the space suit. After conducting research, we learned that 60% of astronauts surveyed said that boot contact caused dorsal foot pain. Based on this notion, along with related factors we decided to work on the dorsum area.

We then studied existing space suit boots.

Pebble Study

Each member placed objects into their socks and then observed the sensations we experienced over the course of an hour.

Chronic Pain Assessment Questionnaires

Taking inspiration from Chronic Pain Assessment Questionnaires.

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Wong-Baker’s faces Pain Rating Scale

Wong-Baker’s faces Pain Rating Scale was useful because it is easier for people to relate to. We added our own pain reference such as getting poked and stepping on a LEGO.

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Test &
Survey
Development

We made the participants to wear socks similar to the ones that the astronauts have to use, and we placed plastic buttons in specific areas of the sock following a nerve map from the dorsal area of the foot.

We made participants wear a snow boot that mimicked the characteristics of having a big size boot (one size fits all)

Then, we attached straps on the boot mimicking the pressure from the straps on the actual space boots. We also asked participants to hold on to bars by using their feet dorsum, similar activity that happens when astronauts complete EVA’s and have to place their feet in restraints, so that they do not drift away.

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Survey Test Scenario

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Survey

Link to Online Survey

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Survey Result

Once the Sensor Garment is developed, we will redo the button test in order to test for accuracy and establish the relationship between the survey (subjective data) and sensors (objective data)

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Sensor Array Development

We explored various ways of approaching the sensor garment, including FSR Sensors and conductive fiber & thread. Ultimately, we landed on a method that used conductive thread and neoprene.

The way this sensor operates is by interrupting a circuit with a sheet of pressure sensitive film called velostat. One side of the sensor has one continuous positively powered thread, and the other side contains individual threads that each lead to their own output, forming an individual sensor. Without velostat, every circuits would be powered on, but adding the velostat generates resistance to the circuits, which decreases when pressure is applied, increasing the current.

A: Conductive Fabric

B: Conductive Thread

C: Neoprene Fabric

D: Velosta

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Prototyping the Sensor Array

Sewing & Wiring of the sensor

Below is a display of the sensor and the conductive thread inside of it look like. The chalk lines indicate where the thread travels inside the neoprene. Neoprene is two layers of fabric joined by a spacer material. Using neoprene, we sewed within the two layers, insulating the conductive thread.

Connecting

E-Textile to Electronics

The fabric ribbon cables terminated in conductive thread loops. We then hooked female headers into, which could be plugged into with traditional male headers and wires and connected to the Arduino boards. Due to the tight spacing between leads, we added an insulating material in between them to avoid interference.

Final Sensory Garment

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Modifying the Boot

To make it more efficient to don and doff the boot with the sensor on, we cut the side of the boot. We subsequently sewed velcro to the cut sides to garner an adjustable fit. Finally, we sewed buttons on pieces of velcro so we had the ability to arrange them as needed inside of the boot in order to create the discomfort necessary to test our survey and sensor.

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Testing

We had participants perform six tasks in total, including standing, walking on uneven terrain, climbing steps, pulling up on a foot bar, coming up onto their toes, and squatting, gathering useful information on fit while actively moving

Raw Data from Test Day

Below is a video showcasing a participant walking on uneven ground, which mimics a rocky terrain and further tests for discomfort. The objective was to create a terrain that mimics the environment on Mars. As observed in the video, the participant would wear left and right sensors while team Kepler integrants would follow along to collect the data.

Data Analysis

We analyzed the data was by timing when the participants realized each aforementioned task. For example, from second 0 to 8 would be walking, from 8 to 16 climbing on stairs and so on. After, we would link the moment when the sensors tested the most pressure during each activity.

Result

For those who felt obvious discomfort, the locations in their drawing match the location determined by the data. We also discovered that the evaluation for two of seven participants for the pressure they felt across all tasks deviated from the data and common trend. As observed from the bottom two pictures, walking was marked as moderate difficulty and climbing steps was marked as slight difficulty. Nonetheless, the data supports that standing on toes caused the most pressure and climbing steps actually caused more pressure than walking.

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Project Growth

Sensor Calibration

Units in pounds of pressure rather than voltage

Processing Software

Better data visualization, storage, and retrieval

Pushing Sensor Garment Design

Bluetooth capability

Improving accuracy

Increasing scope

Real World Implantations

With simple adjustments, the testing system can be used on a diverse array of components of the body for astronauts. Furthermore, this system is also suitable for sportswear and medical use when detection and quantification of discomfort are required.

Team Kepler (from left to right): Alejandro Espina, Eugene Brukhman, Woody Wei.

Woody Wei