Team TEFNUT Home Page

 

Background - What is TEFNUT?

A team of Thayer Students have applied to NASA's Microgravity University this year. The students hope to test a prototype they are designing and building for Engs 89/90: Engineering Design Methodology. Team TEFNUT(Thermal Exchanger for Null-gravity hUmidity Transport), named after the Egyptian god of moisture, is currently hard at work designing and optomizing a Porous Media Condensing Heat Exchanger (PMMCHX) for use on future manned space vehicles. The project is sponsored by NASA's Glenn Research Center and will be completed in March 2011.

Meet Team TEFNUT

Team Members:

    • Sean Currey [Team Contact, Flyer]
    • Broghan Cully [Flyer]
    • Maxwell Fagin [Flyer]
    • Michael Kellar [Flyer]
    • William Voigt [Flyer]
    • Julianna Scheiman [Alternate]

     

Bios of the team members involved in Engineering Design Methodology can be found here.

Project Abstract

NASA is designing the Crew Exploration Vehicle (CEV) to propel humanity beyond the grasp of our home planet to nearby asteroids, Lagrangian points, and eventually Mars. These long-duration missions will require light and compact life support systems that can function reliably with little maintenance for periods of up to two years.

One essential component of life support is maintaining a constant level of humidity in the crew capsule.  Environments that are too humid or too dry are uncomfortable and can damage equipment.  Current dehumidifying systems used in orbit are large, mechanically complex, and must be serviced often.  To solve this problem, NASA Glenn Research Center is developing a promising new system, known as a porous media condensing heat exchanger (PMCHX), to remove moisture from the cabin via the use of porous graphite.

Our team will design, fabricate, and test a condensing heat exchanger that uses porous media to both extract and replenish moisture into the environment.  Our product must be very light, reliable, able to handle peak moisture levels, and able to function in both microgravity and on planetary surfaces.  We will select material for the cooling system pipes, a geometry for the flight-ready exchanger, and the size of the system.  After designing and building our system based on these three variables we will test our prototype using flow and heat transfer modeling, finite element analysis, and analytical models.  Numerical and ground test results detailing the effectiveness of our system will be compared with microgravity flight results.  The flight results will prove the effectiveness of a PMCHX in microgravity and quantify the importance of gravity on the system’s efficiency.

View a copy of the proposal here.

Outreach Program

As part of our project, we have created an outreach program, titled project MISSION, to reach out to underrepresented, geographically isolated students in New Hampshire and Vermont. Stay tuned, out social media pages are still under construction.

Past Dartmouth Projects

This was not the first proposal submitted to Microgravity University by Dartmouth students. Check out the table below for descriptions of past projects.

Research Project Team Members Proposal
Preparation of Intravenous Fluid Bags in Microgravity (2009)
On long voyages in space, it will be necessary for astronauts to prepare intravenous (IV) fluid solutions in microgravity during a medical emergency.  In this experiment, we have engineered a method of mixing IV solutions and removing the air from an IV bag in a timely manner.  First, we will test the effectiveness of using a magnetic stirring device to mix a capsule of solute into 1L of water.  We will then compare this to manually shaking the bag. Next, we will test the how effectively a centrifuge removes air from the bag.  Finally, we will combine the two processes and attempt to mix the bag while it is in the centrifuge.  Removing this air will prevent symptoms similar to decompression sickness and other illnesses associated with the accidental injection of air into a patient.  We will score the results by looking for air bubbles in the IV tube.  The results of this experiment will reveal how effective our equipment designs are, as well as identify areas of improvement in the IV fluid preparation process.

Sean Currey

Derek Lyon

Jason Mintz

Julianna Scheiman

Tom Collier

dartmouth2009
Free-Floating Resistance Exercises for Maintaining Postural Muscles in Weightlessness: A closer lookA Reflight and Enhancement of the 2004 Study (2006)
Multiple studies have shown reductions in muscle cross section area and strength in weightlessness. This affects mainly the anti-gravity (postural) muscles. Currently, astronauts use the following regimen for exercise and training in space: a one hour session of aerobic conditioning 2 days/week, a one hour session of resistive exercise 6 days/week, interval training 4 days/week, and EVA training as needed (1). For the 2004 NASA Reduced Gravity Student Flight Opportunity, a group of students from Dartmouth College tested the effects of short, intense resistive exercises on the activation of postural muscles. These simple exercises could be done by the astronauts at any time during the day, without special equipment, to help maintain the antigravity muscles. They called these exercises the Dartmouth Resistance Exercises for Antigravity Muscles (DREAM). Observation of the electromyogram (EMG) recording on the KC-135 in 2004 indicated that the DREAM exercises were indeed effective in muscle activation. Also, the exercises could be performed easily in weightlessness. We will expand upon the successful initial demonstration of these exercises by: (a) testing a new exercise that activates the hip adductors and abductors along with the others, (b) providing visual feedback on muscle activation during the exercises so the crewmember will know they are providing sufficient muscle activation and (c) improving the electromyogram (EMG) data analysis. Our regimen will be titled DREAM+. Using EMG to quantify the results, we will record the stimulation of muscles from these exercises in a microgravity environment. We will develop a software package to analyze the results and provide the test subject visual feedback on his or her performance. This tool will allow the subject to modify the exercises and movements as they are being performed for maximum efficiency. Our ultimate goal is to develop a set of validated, simple, anti-gravity muscle exercises that could be performed by astronauts at their convenience without special equipment.
2006
 
Volume and Mass Measurement in Liquids in Microgravity For Urine Analysis (2006)
The weightless environment of long-term space flight leads to bone loss as calcium leaves bone and is excreted into the urine. Measurements of urine calcium excretion can be used as a marker for bone loss, helping to determine the effectiveness of bone loss countermeasures. Measuring urinary calcium output requires a measurement of urinary calcium concentration and volume. The focus of this project is on measuring urine volume in space. (Buckey) Hamilton Sundstrand is currently developing an automated system for measuring urine volume in space, the Urine Monitoring System. This system may not be available on all spacecraft or may malfunction, in which case a simple method to measure volume may be needed. In our project we will design, fabricate and test simple methods for determining the volume of urine samples. This device could be used in combination with other simple devices such as the iStat for monitoring urinary calcium output or other biomarkers.(Knaus) For our system, we plan to assume constant urine density, so that mass and volume are interchangeable. This assumption has an associated error of 2 to 3%. We plan to pursue two volume measurement schemes. Our first scheme is to use a simple measurement of centripetal force to determine the mass of a sample: the hand-spun centrifuge. The second scheme involves coupling the urine mass to a spring-mass system and determining the urine mass from the period of oscillation of the spring: a simple harmonic oscillator. In order to test the accuracy and precision of each of our volume/mass analyzers, we will test water in bags similar to the urine collection bags that astronauts have used in the past. We will determine the accuracy of both schemes in microgravity by measuring sample bags of known volume. After the flight, we will make a recommendation as to which approach is preferred based on accuracy results obtained in microgravity and other factors such as the system mass and measurement
2006
 
Free-Floating Resistance Exercises for Maintaining Postural Muscles in Weightlessness (2004)
Muscle atrophy is a big problem for astronauts on long-term assignments in weightlessness. These astronauts particularly suffer upon return to Earth’s gravity due to postural muscle atrophy. The current measures of prevention use heavy, bulky equipment and astronauts are scheduled for daily two-hour exercise periods to maintain muscle mass and aerobic fitness. Evidence exists showing that frequent, brief periods of intense exercise throughout the day may be as effective or more effective than a single daily exercise session. If astronauts had a series of simple exercises they could do on their own without the need to deploy exercise equipment, they could perform this series frequently throughout the day. This may allow them to maintain their muscles more efficiently than with a single exercise session. The goal of this project is to design a set of simple, free-floating exercises targeting five postural muscles that astronauts could perform on their own throughout the day. This series of exercises will be called the Dartmouth Resistance Exercises for Antigravity Muscles (DREAM). The effectiveness of these DREAM exercises in weightlessness will be determined by comparing the level of muscle activation in weightlessness with the activation that occurs when postural muscles are activated in daily life on Earth (ie. standing, toe raises, stair climbing). Four subjects will perform these normal daily activities on Earth prior to the flight on the KC-135, activating our five targeted postural muscles. The activation of these five postural muscles in daily activities in Earth’s gravity will be compared to the muscle activation of these five muscles when targeted with resistance band exercises in weightlessness. Muscle activation will be determined using a surface electromyogram (SEMG). We hypothesize that muscle activation in-flight using the DREAM resistance exercise program will be as great or greater than muscle activation in daily activates. If the weightless exercises do produce substantial muscle activation, they would become a pilot suite of effective exercises that crewmembers could perform to maintain muscle mass while in space.
2004