Stevens Institute of Technology - New Jersey Space Grant Consortium with

Rutgers University

Critical Design Review

Mike Giglia, Ethan Hayon Robert HopkinsMark Siembab, Sean Watts, and Jenny Jean

Mission OverviewRob Hopkins

Mission Overview

• To collect and analyze data for future space research operations through various experiments designed and implemented on a payload.

Mission Overview - Theory of Requirements

• At launch we will begin to take atmospheric readings. As the rocket ascends and the ports are opened completely, air will flow in the dynamic port across our sensors and out the static port.

• This will be able to show us different levels of various gases at changing altitudes.

• Gathered information will provide future payloads an example of what they will come in contact with during flight to avoid using anything that may malfunction or receive interference as a result of the environment. 

• The Earth's atmosphere is composed of 71% Nitrogen, 21% Oxygen, 8% CO2, and 1% various other gases.

Requirements

• One Static Atmospheric Port

• One Dynamic Atmospheric Port

Mission Expectations

• We expect to retrieve a CO2 and H20 concentration gradient as the rocket ascends to apogee as well as descent to earth.

• The data retrieved will assist in environmental studies.

• The physical data will aid in the design of future payloads.

Team Organizational Chart

Example ConOps

Expected Results

• At the beginning of the flight, we expect to have a CO2 concentration of roughly 390 ppm which decreases with altitude.

• We expect a slight increase of temperature due to air friction on the skin of the rocket.

• The strongest vibration should be experienced during the initial Orion burn.

Design DescriptionEthan Hayon

De-Scopes

• Elimination of all gas sensors except CO2 due to heating and cost concerns.

• Simplification of the Latch Circuit using a Thyristor instead of an NPN-PNP chain system.

Off-Ramps

• Problem: Possibility that the pinch valve will not remain open during the flight, causing a catastrophic loss of data.

• Solution: Possible dedicated battery for the pinch valves.

Off-Ramps

• Problem: It may be difficult to mount the ACV securely due to its cylindrical shape.

• Solution: The shape of the ACV can be changed to a rectangular prism to allow for more secure mounting.

Off-Ramps

• Problem: The center of mass of the payload is offset 0.37 inches from the center along the Z-axis.

• Solution: This will be solved by moving components between the two plates until there is an even weight balance between them.

Prototyping/AnalysisMike Giglia

Prototyping/Analysis

• A latch circuit was successfully prototyped using a thyristor PNP-NPN system.

• Humidity, Pressure, Temperature sensors have also been tested.

Electrical DesignMark

Siembab

Electrical Schematic

Text

The ATMega displayed is an Arduino Mega

The SEN is essentially a breakout board, the

schematic is not displayed.

Power Latch Circuit

Power Budget

Mechanical DesignMike Giglia

Payload Isometric View

Center of Mass

Center of Mass (offset from origin)

Center of Mass

• The center of mass calculated by SolidWorks:o X: 0.00 incheso Y: -0.08 incheso Z: 0.36 inches

• We will work to improve the center of mass of our payload.

• The center of mass along the Z axis can be corrected by relocating objects between the plates to balance them better.

Dimensioned Drawing

RisksMark Siembab

Risk Walk-Down

• The biggest risk addressed in the PDR was the exceedingly long heating time associated with the original gas sensors.

• Since then, we have reduced our gas sensors to just one infrared CO2 sensor which does not have a heating element and thus requires not heating period.

Risk 1

• Rsk.1: Low sample time establishes a poor CO2 gradient

• Rsk.2: Startup period not complete by T minus zero

• Rsk.3: Power loss prevents redundant valve opening

Software DesignSean Watts

Software Flowchart

User Guide Compliance

Mark Siembab

User Guide Compliance

• Mass without canister according to SolidWorks = 1.7 lbs.o CG is within the 1x1x1 envelope. It is located off the center of the

payload by (0, 0.8, 0.37)o Batteries: 4 x 9 Volt alkaline in series to provide 32V to be used around

the payload.o Thyristor-based latching circuit with g-switch activation supplied power

to the payload.o High voltage, low current pulses produced by piezo vibration sensor.

These pulses will then be reduced using resistors to permit data collection. This component will be insulated with conformal coating to inhibit spark jumps.

o One static and one dynamic port are used, both of which are protected by redundant safety valves.

Sharing Logistics

• We are sharing the canister with Mitchell Community College.o They are harvesting electrical energy throughout the

rocket flight.

• Teleconference scheduled for next week.

• The platform interfacing strategy is to be determined during the conference call.

Manufacturing PlanMike Giglia

Mechanical Elements

• What needs to be manufactured?o ACV out of PolyCarbonate

• Scheduleo SolidWorks 3D Modelo Parts Orderedo Mechanical Assemblyo Testing

Electrical Elements

• What needs to be manufactured?o Sensor Board (SEN)

• Scheduleo Eagle schematics createdo Schematics converted to eagle

board fileo Board file sent to PCB fab-houseo Electrical components orderedo Assembly of electrical

components onto PCBo Testing

Software Elements

• Blocks of code to complete:o Flash (SD) card I/Oo Sensor reading (CO2, H20, Vibration, Temperature)o Data Protection (latch)

• Scheduleo Acquire development platform (Arduino Mega)o Refine flowcharto Prototype code segmentso Implementationo Assemble the code segmentso I&T (Integration and Testing)

Testing PlanSean Watts

System Level Testing

• ACV Pressure Testingo Ensure that the ACV can handle the dynamic pressure during

the rocket flight.o Utilize SolidWorks to simulate a pressure testo Pressurize the finished vessel with an air compressor.o The test passes if the ACV remains in tact and there are no

leaks.

• The CO2 sensor will be tested by filling the ACV with CO2o This also will ensure that the AVR is correctly reading the

sensoro Also a useful software test

• These tests will be performed in February as the components are being completed.

Project Management Plan

Ethan Hayon

Schedule

Budget

Conclusion

• Issueso Sourcing a rechargeable battery which can supply 24+

volts and replace the 9V alkaline arrangement while falling within size and mass requirements.

• Final components will be purchased and the majority of the project time will be devoted to construction.

• Over winter break the ACV will be machined and pressure tested. If necessary, the layout inside the ACV will be adjusted to optimize airflow to the CO2 sensor.