P16104: Microfluidic Spectroscopy for Proteins within CubeSats
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Systems Design

Table of Contents

Team Vision for System-Level Design Phase

During the systems design phase, we planned to determine which type of protein imaging we would use for the bioassay, as well as create a complete overview of each of the systems required to make the bioassay a success once it reaches orbit. We also planned to reach out to other faculty and staff at RIT to find further expertise with regard to our total system. Additionally, we each set individual goals at the end of Problem Definition that we each planned on accomplishing by the end of Systems Design.

In addition to completing all of the assigned weekly tasks in MSD, we were also able to accomplish our group goal. Using the tools given to us in MSD we were able to determine that we will be using FRET to image proteins. With this determination, we have been able to identify the other systems we will need to focus on to reach success. We also were able to reach out to additional faculty to help us with not only the bioassay, but also the mechanical and electrical systems. With regard to our individual goals, we were each able to meet many of our goals and as a team can move forward to the Subsystem Design.

Problem Statement

Current State: Three CubeSats have successfully launched and performed biological experiments but none have examined proteins folding directly.

Desired State: A functional prototype that performs folding analysis of proteins and contains on-board electronics that store and transmit data for analysis.

Project Goal: Design an automated bioassay that can be integrated into a CubeSat to study protein folding in microgravity.

Functional Decomposition

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Engineering Requirements Mapping

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Benchmarking

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Morphological Chart and Concept Selection

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Selection Criteria

  1. Protein data is reliably stored and collected
  2. Protein data is reliably transmitted
  3. CubeSat survives launch
  4. Device fits within 3U CubeSat
  5. Cost-effective
  6. Reliance on orientation

Concept Development

Pugh Chart with GeneSat as Datum
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Pugh Chart with PharmaSat as Datum

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Pugh Chart with O/OREOS as Datum

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Systems Architecture

Flow Down Charts

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Primary Concept

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Secondary Concepts

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Feasibility: Analysis, Simulation

Imaging System

LED based fluorometry is feasible according to the diagram below.

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http://link.springer.com/chapter/10.1007/11493785_35

Power Consumption

The below values are preliminary pending parts selection. Despite this uncertainty in our specific parts selection these numbers show that the total power consumed by the electronics in the well within the overall power budget for the CubeSat.

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UV LED and Tryptophan Fluorescence

The below information proves that this UV LED can be used as the light source for protein analysis.

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For our project we are analyzng hemoglobin which has intrinsic tryptophan fluorescence. According to the Oregon Medical Laser Center, the excitation wavelength of tryptophan is 270 nm and the maximum emission wavelength is 354 nm. This means that the tryptophan will excite under ultraviolet light and the emission wavelength will transmit using a UV Bandpass Filter.

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The filter UV-Vis has the appropriate band pass filter properties to capture the emitted tryptophan wave length.

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Microfluidic Mixing and Design

Feasibility of evenly mixing a small amount of solid (20-100ug) with a small amount of liquid within a microfluidic system was analyzed. Concentrations of lyophilized proteins can range from 100 to 200 ug/mL and we would like to use a much smaller volume.

A commonly used tool in spectroscopy is a Corning 96 well plate. This plate was used as a benchmark, and the diameter of a single well was used to do further calculations. Only a single well was considered because during spectroscopy, the light is focused into only one of the small wells which makes it a good candidate size. Using the diameter given by Corning online, and a goal volume of 250mL, the size of the main chamber that would sit beneath the light was calculated. All calculations were done considering the solid and reagent must remain separate until the experiment is to be conducted.

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As for the actual channel itself, preliminary ideas were brainstormed as to how to mix the protein and the reagent. The diagram below shows a situation in which the components would be forced together using pressure via needles and a motor.

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Thermal Stability

As a satellite orbits the earth it goes in and out of the path of the sun’s rays. This is often referred to as going in and out of eclipse. As a result the satellite experiences very hot and very cold temperatures. This creates an environment of Thermal Instability.

Multilayer Insulation, pictured below was utilized by O/OREOS, PharmaSat, and GeneSat. Kapton MLI blankets prevent the spacecraft from excessive heat due to radiation and excessive heat loss from components during eclipse. Currently we do not have the ability to manufacture it here at RIT. It is not feasible for us to purchase due to cost. A single layer kapton MLI blanket - $4000 per square ft. An alternative is Kapton tape, which is much cheaper, but not as effective.

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Heat Pipes are small tubes or pipes with high thermal conductivities which allow them to Direct heat away from vital components. They are often made from multi-walled carbon nano-tubes with a diameter of about 200nm. They are a feasible option if manufactured at RIT. Currently RIT manufactures amorphous carbon nanotubes at RIT which do not have the same properties as their hexagonal counterparts.

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Vibrations

Materials and Coatings

Specialized coatings and materials allow for increased thermal regulation of vital components. Gold plating: high heat retention - α/ε = 10 White paint: low heat retention - α/ε = 0.31 Use low conductivity materials to isolate payload i.e. Ultem and Delrin This is a relatively inexpensive option making it feasible for integration.

Spring/damper systems reduce oscillations on payload from vibration testing By simply looking at a spring, and the spring equation: F = kx Only about 0.5cm space per each spring which is not enough room to be feasible.

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Design and Flowchart

This flowchart shows the general breakdown for designing a CubeSat. The aspects that are within the scope of this project are highlighted in green.

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Risk Assessment

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Design Review Materials

The following presentation was given on October 1, 2015: Systems Design Review.

This handout was given out to the audience during the review: Phase 2 Review Handout.

Plans for next phase

Next Phase Gantt Chart:
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Personal Goals for Next Phase

August Allen's Three Week Plan: August's Goals.

Mallory Rauch's Three Week Plan: Mallory's Goals.

Anna Jensen's Three Week Plan: Anna's Goals.

Andrea Mazzocchi's Three Week Plan: Andrea's Goals.

James Lewis's Three Week Plan: James's Goals.

Matthew Glazer's Three Week Plan: Matthew's Goals.

Darin Berrigan's Three Week Plan: Darin's Goals.


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