P18104: High Altitude Balloon Instrumentation Package
/public/

Systems Design

Table of Contents

Previous Phase: Problem Definition | Team Page: Home | Next Phase: Preliminary Detailed Design

Project Recap

The High Altitude Balloon Instrumentation Platform (HABIP) is a multi-functional system that allows users to collect and analyze data from near-space experiments. The device records internal data, and also telemeters data that has been gathered from an array of sensors to a ground communications center. The goal of this project is to create the aforementioned array in a configuration that is lightweight, cheap to manufacture, and highly reliable. The final product will undergo a mission lasting for several hours in harsh conditions, and will parachute back to Earth from an altitude of over 100,000 feet to be recovered and analyzed. This project seeks to improve upon the progress of two former MSD groups: P17104 and P17105, and is intended to be a design which can be further improved in the future.

Team Vision for System-Level Design Phase

Phase Summary:

Functional Decomposition

Purpose

Define the total list of functions and subfunctions, based on the Customer and Engineering Requirements, that must be delivered by the final design. This establishes the need for specific concepts necessary to deliver the overall objectives of the project

Method

To create this document, the engineering specifications and customer requirements were reviewed to understand the most basic needs of the HABIP. Some systems achieve the goals of many requirements, while other functions are singular. In this way, each system concept that is generated throughout this phase is done so with the purpose of satisfying at least one of the lower-level functions set forth in this document.
Functional Decomposition

Functional Decomposition

To view the full document, click here.

Benchmarking

Purpose

Avoid redundant work by identifying already available solutions and concept options. Most benchmark products were found by previous HABIP teams, here complied for analysis.

Temperature

Temperature

Temperature

Pressure

Pressure

Pressure

Humidity

Humidity

Humidity

Camera

Camera

Camera

Reaction Wheel Motor

Motor

Motor

GPS

GPS

GPS

APRS

APRS

APRS

Transceiver

Transceiver

Transceiver

GRSS Buzzer

Buzzer

Buzzer

Concept Development

Purpose

To generate new concept options or combinations that can potentially exceed the benchmark concepts

Morphological Chart

Categorical list of multiple concept options to satisfy each necessary function. Brainstorming leads to some concepts that are more feasible than others, though this tool can be used to create a conglomerate system that serves all necessary customer requirements.
Morphological Chart

Morphological Chart

To view the full document, click here.

Feasibility: Prototyping, Analysis, Simulation

Purpose

  1. Confirm that the selected concepts can deliver functionality.
  2. Understand what is physically available as a jumping-off point for testing and prototyping.
  3. Support the evaluation of concepts with quantitative information.

Background

Dr. Patru has requested that the design stay generally the same as previous models apart from modifications to the following systems:

The customer will be consulted with regard to any ideas about how to (re)design a system, part, or software. Otherwise, the previous design will be iterated in pursuit of satisfaction of all requirements.

Method

Most of the action in this phase was centered around using the efforts from last year to understand what steps can be taken moving forward. The physical and digital systems were reviewed and restored to analyze what worked and what failed, as well as what systems could be treated as a direct continuation of previous work (as opposed to starting with a blank slate). The research that was conducted last year was also reviewed, as this information remains the guiding force in what is feasible in a final product.

Simulation/Understanding of Previous Systems

Research

The vast majority of this research was modified from information found on previous projects. Data and Telemetry Transmission
For data and telemetry, we will be using the 2m frequency band, a common Amateur radio band, which uses a frequency of (144-148 MHz). Previous teams used a 2m Yagi antenna (brand: C3i, model: FO12-144). It had a gain of 12.6 dBi.
The antenna used on previous METEOR designs is a dual-band Comet SBB-1, which had a gain of 1.5dB for 2m.
Based on the transmit and receive antenna gains, the total combined antenna gain for the 2m system is 14.1dB.
Previous research based on the free space path loss formula (below) indicates that a 9 dB gain adjustment is necessary to account for adjustment from 70cm to 2m antenna. Thus, the total gain used to determine power requirements for data and telemetry transmission is 23.1 dB. Since the required distance of transmission is roughly 26.5 miles, it follows using the graph below that a 2m antenna will require of between 1W and 5W (approximately 2W).
Free Space Path Loss Equation

Free Space Path Loss Equation

2m Antenna Gain, Distance, and Power

2m Antenna Gain, Distance, and Power

Environmental Factors
From the vertical temperature profile, temperature will range from room temperature (about 23 degrees Celsius) to -57 degrees Celsius. In the Troposphere, temperature decrease 6.5 degrees Celsius per km; the jet stream is also at this level of the atmosphere. The Tropopause is the border between the Troposphere and Stratosphere; air temperature is constant in this layer. Temperature increases with height from the base of the Stratosphere until the service ceiling of the HABIP is reached.
As altitude increases, atmospheric pressure and the concentration of water vapor/particulate all decrease.
These considerations are important as it will affect the ability to heat and cool the components on the HABIP. Previous projects have had to focus primarily on cooling, because the ATV is a significant source of thermal energy that cannot be dissipated easily at high altitude (where convention is minimal). Since the new design will utilize digital video, the need to cool the system will be less significant, though more research will have to be done to determine if there is a need to heat components in the new configuration.
Environmental Factors (Vertical Temperature Profile, Atmospheric Pressure and Particulate Concentration by Altitude)

Environmental Factors (Vertical Temperature Profile, Atmospheric Pressure and Particulate Concentration by Altitude)

Weight
A preliminary estimation of component weights was compiled, with conservative estimates made when exact weights were not known. The target weight is between 6-10 lbs, which this estimate satisfies. Additional steps will be taken to understand if an additional ~2 lbs can be shed from the design, in order to bring the weight below 6 lbs (which reduces the FAA regulatory requirements that would govern a launch). It is notable that none of the components that are being replaced face an increase in weight.
Weight Approximation

Weight Approximation

Concept Identification and Selection

Purpose

  1. Develop multiple concept options to deliver the required list of functions.
  2. Ensure that concepts (means) are available to deliver every required function.
  3. Select the optimal set of concepts that can be integrated to meet the project objectives.

Restate Engineering Specifications

The Engineering Specifications defined in the last phase are reiterated below to indicate what the functional goals of concept selection are.
Engineering Specifications

Engineering Specifications

To view the full document, click here.

Pugh Chart

The Pugh Chart is used to select a concept based on the scores of various categories. The classification system is kept consistent with the previous iteration of this project, and the final design of the HABIP from 2016-17 is used as the datum for reference.
Pugh Chart

Pugh Chart

To view the full document, click here.

Systems Architecture

Purpose

Define system functions, as well as flow of energy, information, and forces, on a high level. Determine how sub-systems are interrelated.

Previous Block Diagram

Block Diagram

Block Diagram

Flow Diagrams

Flow Diagrams

Flow Diagrams

To view the full document, click here.

Block Diagram

Block Diagram

Block Diagram

To view the full document, click here.

Risk Assessment

Technical

Resource

Safety

Environmental/Societal

Plans for Next Phase

The next phase of the project involves the completion of several key tasks:

Design Review Materials

Functional Decomposition
Morphological Chart
Engineering Specifications
Pugh Chart
Flow Diagrams
Block Diagram

Home

Problem Definition | Systems Design | Preliminary Detailed Design | Detailed Design

Build & Test Prep | Subsystem Build & Test | Integrated System Build & Test | Customer Handoff & Final Project Documentation