ROCKY: RDR BRIEFING TEAM CD

PMEric

Powell

LSEJanelle

Williams

ESTACAPCE

Nathan Sandlin

CoC

AEQiao

AE Ricardo

Environment Austin

Sci Ops Jeremiah

SCEJustin Smith

UTEPDaniel

ThermalAndrew

StructureHagen

TuskegeeKhiante”

Team CD

ROCKY

Goal: Design and Develop a 3U CubeSat•Measures lift, drag, magnetic fields, radiation, and GPS Performance

in LEO•Actively controls descent into the atmosphere to maximize duration

in LEO

Customer: U.S. Army Space and Missile Defense CommandProcess: Agile SE processes

Stakeholder: U.S. Army Space and Missile

Defense Command

StakeholderRequirements for ROCKY

Magnetic Fields

Lift and Drag

GPS Performance

in LEO

Radiation

Actively Controls

Descent into Atmosphere

from LEO

At lease 1 Science

enhancement Option

REQUIREMENTSPROJECTSpecifications

● 3U Cubesat < 10kgDRM:

● 300 km circular orbit @ 28.5°● 1000 km x 100 km orbit @ 28.5°● 150 km circular orbit @ 28.5°

Measures:● Lift & Drag, Magnetic

Fields, Radiation, GPS Additionally:

● Actively Controls Descent into Atmosphere from LEO

● At least one science enhancement option, TBD

FUNCTIONAL● Sensory● ADAC● COMM● Command and Data

Handling● Power● Thermal● Structural● Propulsion

ENVIRONMENTAL● Survivable in LEO

Radiation, magnetic fields and Temperature fluctuations

● No space debris after 25 years

SubSystem RequirementsThermal-Thermal subsystem must provide the correct heat distribution across the space craft required to keep all electrical components within their optimum operation range temperatures.ADACS-The attitude determination and control system must perform the duties of stabilizing the space craft and meet the pointing requirements required by the payload’s mission.Communications-Communications must provide reliable communication to a ground station on earth in order to transmit/receive data and commands.Structural-The structural component must provide a secure base for all components to secure to and still maintain its 3U format size. It must also provide shielding from debris and radiation.

Driving Requirements

• Outer structure must be 340.5X100X100 mm

• Must be powered off from time of integration to time of deployment

• CubeSat must have method to constrain deployables

• No pyrotechnics may be used on the CubeSat

• No components can extend past 6.5 mm normal to outer surfaces

Requirements-Space Craft

Thermal ADACS Communications Structural Structural (cont’d)

Build materials must adhere to NASA standards

No pyrotechnics may be used on the cubeSat

Radio output <= 1.5 at TX antenna input Must have 1 deployment switch on rail standoff

Rail must have 75% contact with PPOD rail

Total mass loss <= 1% Propulsion systems must adhere to AFSPCMAN 91-710 Vol 3.

CubeSat must have 2 independent RF inhibits All parts of structure must remain intact Maximum mass of CubeSat is 10kg

Collected volatile condensable materials <= .1%

Propulsion systems must have 3 fail safes to activate system

Operators must be licensed for proper radio frequencies and have proper documentation

Build materials must adhere to list of NASA approved materials

CG must be within 2 cm of geometric center in X and Y direction

Must have battery protection circuit to prevent cell unbalancing

Must be powered off from time of integration to time of deployment

Radio systems must adhere to U.S. radio license agreements and restrictions

Outer structure must be 340.5X100X100 mm

CG must be within 2 cm of geometric center in Z direction

Thermal vacuum bakeout must be performed to specs of a launch provider

Antennas must wait 30 minutes after ejection from P-POD before deploying

+Z face must be inserted first into PPOD Aluminum 7075, 6061, 5005, 5052 must be used for main structure and rails.

Radio system cannot generate or transmit signal from time of integration until 45 mins after deployment

No components can extend past 6.5 mm normal to outer surfaces

Rails and standoffs must be hard anodized aluminum

CubeSat must have method to constrain deployables

Must perform random vibe test to specs of the launch provider

Rails must have min width of 8.5 mm, surface roughness <1.6 mm, and edge radius of at least 1 mm

REQUIREMENT PERTURBATIONS• Active descent measures will most likely require propulsion

• Sensor suite will require thermal management to stay within its performance envelope

• Uncertainty factors in measuring lift and drag

• Space debris/Radiation: Any large space debris/radiation could disable/dismember CubeSat

• External Inertial forces: Excess momentum could overcome the recovery limits of ADACS system

• Lack of Solar power: Create decreased life cycle for components dependent on solar power

• Temperature fluctuations: Extreme changes in temperature could cause flexing/warping

CUBESAT SOA TECHNOLOGY

• 2003 AAS Paper on satellite life extension by precision pointing and orbital maneuvers, i.e. Hohmann Transfer

• 2001 Paper by AIAA on the use of tethers to extend the usable life of small satellites

• Measuring differential drag by adapting a study by Matthew Horsley

PARTNER COMMUNICATION

UTEP TUSKEGEENone at this time

ESTACANone at this time

College of Charleston Contact Established Delegation of

responsibilities begun integration of

personnel into appropriate subsystems

Contact Established Rough team structure

known Research progress

update

Backup

Payload Sensory Subsystem•Acquires scientific data as well as monitoring the health and progress of the various subsystems of the

CubeSatInstrument Considerations

•the payload sensors subsystem should be light in weight, consume a small amount of power, be high in sensitivity, and should be able to produce undistorted analog and digital signals

•supplied with required controlling commands from CD&H subsystem•Output will be transmitted to the ground station through the Communication Subsystem

• Working Closely with the College of Charleston

WBS Definitions

Attitude determination and control subsystem•Measures and controls spacecraft’s angular orientation

•Simplest spacecraft are either uncontrolled or achieve control by passive methods such as spinning or interacting with Earth’s magnetic or gravity fields

•May or may not use sensors to measure attitude and position

•Capability of attitude control system depends on the number of body axes and appendages to be controlled, control accuracy and speed of response, maneuvering requirements, and disturbance environment

WBS Definitions cont’d…

Command and data handling subsystem•Distributes command and accumulates, stores, and formats data from spacecraft and payload•Could be combined with communication to form tracking, telemetry, and command subsystem•Includes: general processor (computer), data buses, remote interface units, and data storage units•Data rate and data volume determine size

Power subsystem•Provides electric power for equipment on spacecraft and payload•Consists: power source (solar cells, RTG), power storage (battery), power conversion and distribution equipment•Power needed to operate equipment and power duty cycle determine subsystems’ size

•Must consider power requirements during eclipses and peak power consumption

•Must account for solar cell and battery life limits•Beginning-of-life (BOL) •End-of-life (EOL)

WBS Definitions cont’d…

WBS Definitions cont’d…Thermal subsystem•Controls spacecraft equipment’s temperatures•Ways

•Passive•Active

•Passive•Physical arrangement of equipment•Thermal insulation and coatings

•Active•Electrical heaters, high-capacity heat conductors, heat pipes

•Amount of heat dissipation and temperature required for equipment to operate and survive determine size

Structural subsystem•Carries, supports, and mechanically aligns spacecraft•equipment•Cages and protects folded components during boost and•deploys them in orbit•Primary structure – load-carrying structure sized by

•Strength needed to carry spacecraft mass through launch accelerations and transient events during launch•Stiffness needed to avoid dynamic interaction between spacecraft and launch vehicle structures•Secondary structure – consists of deployables and•supports for components, designed for compact packaging and convenience of assembly

WBS Definitions cont’d…

Propulsion subsystem•Controls spacecraft orientation •Actively controls decent with orbital maneuveringPropulsion types

•Cold Gas - simple and reliable •MonoPropellant - low thrust, and ineffecient, but reliable •Resojet - energy demanding•ION/Hall-effect Thruster - inefficient at small size

WBS Definitions cont’d…

Communication Subsystem•Provides linkage to relay data and send commands

•Information flowing to spacecraft consists of commands and ranging tones•Information flowing from spacecraft consists of status telemetry, ranging tones, and payload data•Basics: receiver, transmitter, wide-angle antenna•Receives and demodulates commands, modulates and transmits telemetry and payload data, and

receives and retransmits range tones•Data rate, allowable error rate, communication path length, and RF frequency determine size

•Working Closely with UTEP

2003 AAS Paper on satellite life extension by precision pointing and orbital maneuvers, i.e. Hohmann Transfer

2001 Paper by AIAA on the use of tethers to extend the usable life of small satellites

Measuring differential drag by adapting a study by Matthew Horsley