Status Report #2

Status Report #2

MAE 435: Project Design and Management II

CubeSat Project

Old Dominion University

Virginia CubeSat Constellation

March 14th, 2018

Advisors: Dr. Robert Ash and Dr. Dimitrie Popescu

Team: Robert Bossinger, Jordan Byrd, Zachary Campbell, Mariano Chacon, Charles Chiou, Avery Corbett, Thomas Crouse, Justin Hernandez, Westin Messer, Susannah Miller, Cody Steele, Joseph Vogel, Kimberly Wright, Wade Yeary

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NOTE: Completed tasks have been added onto the existing lists from the first status report. Any current issues have been updated from first report.

Mechanical (completion 70%)

• Design (completion 90%)

• Objectives

• Deliver a completely fabricated and assembled CubeSat chassis that will house the stacks, containing electrical hardware and boards. Determine a hinge design for the drag brake payload, that will withstand the forces experienced during deployment of brake petals.

• Completed

• The chassis skeleton has been machined without screw or switch holes. Lars has completed chassis design files and will be finishing up structure in the coming weeks. The drag brake hinges have undergone new design iterations and a design has been chosen and analyzed with Patran, a Finite Element Analysis (FEA) tool. The FEA analysis has been reviewed by Dr. Hou and has been approved. Action ToolKit Services has final drawing files and will be fabricating hinges in the coming weeks. Deployment switches have been chosen and purchased. The antenna team has sent final antenna assembly to Windform for printing. Actual components were received over Spring Break.

• Issues

• Design phase is nearly over, so the team will have to switch gears to testing and integration. There will be a learning curve the team will have to overcome in order to successfully test and integrate the mechanical and electrical components.

• Lead-time required to complete chassis and anodization.

• Assembling all the chassis components and making sure everything fits properly. We need to determine how and who will be doing it.

• ADCS (completion ?%)

• Objectives

• Determine and control orientation of the CubeSat. ADCS is necessary to accurately measure density of the Earth’s atmosphere in Low Earth Orbit (LEO), optimal power generation, and drag brake deployment.

• Completed

• Earth Orientation Vector – The algorithm is ready to be turned over to electrical/software for implementation.

• Albedo Sun Sensor Filtering – The C++ code needs to be verified for implementation by electrical team.

• Attitude Determination from Sun Vector – The algorithm is written in MATLAB and needs to be turned over to electrical and software team for integration. A sixth sun sensor was purchased to simplify the algorithm since all sides of the CubeSat will be able to receive intensity readings. Collaboration with industry support and the other universities will help in developing a proper testing methodology.

• Issues

• Still no information/software turnover from the previous ADCS subject matter expert. Some items have been recovered from the drive.

• Previous version of detumble script has been acquired; we will need to become familiar with the script and make any updates/ adjustments necessary.

• The graduate student is still aiding in the completion of the team objectives. Industry support has been presented to the team and a technical summary detailing what has been completed has been sent to the company. The industry/graduate support has concluded that using our current magnetorquers to project control for a third axis is not feasible. Further research into the effects of loss of control for this axis needs to be a priority moving forward; however,

• Thermal (completion 90%)

• Objectives

• Determine the various CubeSat heat sources and determine the effects it will have on the functionality of the satellite, during the orbital lifetime. The thermal analyses performed will identify the temperature tolerance range, the satellite can withstand and still function properly, within the parameters of the mission.

• Completed

• The temperature range the CubeSat can withstand, while still functioning properly has been identified, 150 C to -80 C. This range of values was determined through Systems ToolKit (STK) software. The temperature range data will assist in the determination of the optimal deployment time. STK was also utilized to determine solar energy received by satellite. The power supplied to the various systems were determined from analysis data.

• Issues

• There are no current issue in this subteam.

• Orbital (completion 90%)

• Objectives

• Determine and model the expected orbital path of the CubeSat, for the duration of the mission. This model will allow for the determination of the best-case-scenario deployment window, ensuring the satellite will be preferable positions/ locations to receive maximum sunlight and solar radiation.

• Completed

• An orbital model has been created, simulating and tracking the expected flight path of the CubeSat. The reference frame of this analysis was the International Space Station (ISS). This information will become crucial when calculations and simulations are run to determine the ideal deployment window, from NanoRacks. This time window will ensure maximum solar energy/ sunlight exposure for the solar panels on the satellite. This information will then be presented to NASA to provide justification for requesting a deployment time/ window. A satellite lifetime, orbits per day/ number of times satellite passing over ground station, orbital decay, and optimal launch window analysis has been completed.

• Issues

• There are no current issues in this subteam.

• There is a large launch window and unknown deployment date (more of a concern/ not issue affecting current work progression)

Electrical

• Hardware (Completion: hardware design - 100%, hardware manufacturing - 30%)

• Objectives

• Design a multi-board, PC/104 PCB stack. There are eight boards in total and seven of will be disengaged by ODU. The eighth board is a pre-built EPS from GOMspace. The seven boards designed by ODU consist of the main processing, UHF radio, UHF antenna, GPS, GPS antenna, Z-axis sun sensor and temperature sensor, and prototype sun sensor and temperature sensor board.

• Design of auxiliary systems in the PC/104 stack that include burn wire mechanisms, deployment confirmation systems, EMI and radiation shielding, power production and storage, and hardware-based fail-safe systems.

• Completed

• All of the electrical schematics and PCB have been completed.

• A partial run of just the radio and GPS antenna PCBs were sent off to be manufactured. These two boards have impedance matched routes and require physical verification of compatibility with the pre-built board. Once these boards are approved, then the remaining boards will be ordered.

• Issues

• Unmotivated individuals on the ODU electrical team.

• Loss of team members – we went from 12+ people to 4 people.

• Making sure all the boards meet the build tolerances of the manufacturer.

• Ordering the PCBs proved far more time-consuming than anyone initially anticipated.

• Potential redesign needed for radio and GPS boards

• Software (Completion: software design- 65%, software build - 15%)

• Objectives

• Create a custom port of the µC/OS-III RTOS for the Atmel SAM4E16C MCU.

• Develop an adaptive data management and housekeeping system (DM-HK).

• Develop an adaptive, multi-staged, total-system, run-time diagnostic and digital triage system (RTD-DT).

• Integrate the OS with ADCS algorithms.

• Integrate all subsystems together.

• Data collection and storage rates need to be officially decided

• Completed

• The port of µC/OS-III was completed in addition to the task block framework.

• The operational order and frequency of tasks has been decided, but will need optimization once initial full system testing begins.

• Unofficial data collection and storage rates were decided so that development could continue while the official rates are being deliberated about.

• Issues

• Unmotivated individuals on the ODU electrical team.

• Loss of team members – we went from 12+ people to 4 people. This caused workloads to be shifted towards hardware development and testing. So software development hasn’t been heavily worked on lately, but now that PCBs are done, workload is shifting back to software.

Virginia CubeSat Constellation (VCC)

• Licensing (completion 45%)

• Objectives

• Submission of individual licenses for each university to obtain an FCC license.

• Completed

• First round of information submission completed. Each university has received reviews and is currently making necessary adjustments and revisions. Adjustments and updated information will be resubmitted for a final review and submitted for approval by the FCC. Template for SpaceCap data will be the next step.

• Issues

• Data missing for submission of FCC Data Sheet

• Nature of custom antenna on satellite; design and signal TBD

• Further forms to fill and submit; missing data

• There is still the concern about the project/ delivery timeline.