HokieSat IntroductionHokieSat Introduction

Daniel PedrazaDaniel PedrazaSystems & OperationsSystems & Operations

HokieSatHokieSatdpedraza@vt.edudpedraza@vt.edu22 August, 200222 August, 2002

OverviewOverview

1. Introduction2. Mission & System

Overview3. 3CS Mission4. ION-F Mission5. Design/

Configuration6. Structure/Mass7. Propulsion8. Testing

Mission and System OverviewMission and System Overview

• Air Force Research Laboratory (AFRL)– “TechSat-21”

• Investigate small, distributed spacecraft systems

• Missions of larger, single platforms

• University Nanosatellite Program (UNP)– Purpose:

• help explore and implement technologies of small satellites

• 10 schools

Participating UniversitiesParticipating Universities

Emerald Orion 3-Corner Sat

ION-FNanosat-1Nanosat-1 Nanosat-2Nanosat-2

Mission Flight

Program InstitutionAnticipated

Shuttle FlightMin Alt / Incl

/ On-Orbit LifeStanford USanta Clara

MITStanford U

Utah State UU of Washington

Virginia TechArizona State U

U of Colorado at BoulderNew Mexico State U

350 km / 36 deg / 2 months

Nanosat-2

Three Corner Sat

ION-F

June '03

Nanosat-1Emerald

April '03325 km / 28.5deg

/ 2 monthsOrion

Mission and System OverviewMission and System Overview

• VT-ISMM– Virginia Tech Ionospheric Scintillation Measurement Mission– Single satellite investigation– Design quickly integrated with:

• Utah State University

• University of Washington

• VT-ISMM =====> ION-F

Mission and System OverviewMission and System Overview

• ION-F Formation Flying Mission– NASA-Goddard Space Flight Center (GSFC)– Many algorithms developed at GSFC– Earth Observer 1 (EO-1) flies with Landsat 7– Three (3) satellites with propulsive capabilities– Demonstrate more involved formation flying routines

Nanosat-2 Brief Milestone Nanosat-2 Brief Milestone ScheduleSchedule

Mar01Mar01 Sep01Sep01 Mar02Mar02Jun01Jun01 Dec01Dec01

MSDS Fabrication

CDR

Phase 0/1SafetyReview

NanosatDelivery

Integrationand Test

01 December 01

15 July 01

25 May 01 (est.)

04-06April 01

Phase 2 SafetyPackage Development

Phase 3 SafetyPackage Development

University Nanosatellite Program University Nanosatellite Program OverviewOverview

NASA Shuttle Hitchhiker Experiment

Launch System (SHELS)

AFRL Multi-Satellite

Deployment System (MSDS)

University Nanosatellites

DESCRIPTIONNine U.S. universities are producing nine nanosatellites.

The nanosats will be deployed via 2 flight missions from Space Shuttle SHELS hardware (Nanosat-1 and Nanosat-2)

The nanosats are organized into 3 subclusters for the purposes of demonstrating formation flying, inter-satellite collaborative processing/ communication, and autonomous control operations and data downlink

Each nanosat cluster incorporates unique technology demonstrations and science measurement capabilities

• Sponsors: Air Force Research Labs, NASA’s Goddard Flight Center

Three Corner Sat

Introduction/Systems

Arizona State University

New Mexico State University

University of Colorado at Boulder

3 CS Introduction/System3 CS Introduction/System

• 3 universities working together to develop constellation of 3 identical satellites

• ~2 year development schedule• Launched as stack on NASA Space Shuttle• Each university emphasizing its past heritage • Innovative, low-cost solutions & development

encouraged

3CS Mission3CS Mission

3CS Mission Objectives3CS Mission Objectives

•Inter-satellite Communications

•Virtual Formation Flying

•Distributed & Automated Operations•Imaging

•Modular, Generic Design

•Micropropulsion Experiment

•Student Education

ION-F

Introduction/Systems

Virginia Tech

University of Washington

Utah State University

ION-F Introduction/SystemION-F Introduction/System

• Investigate satellite coordination and management technologies and distributed ionosphere scintillation measurements

• Coordinate on satellite design, formation flying, management mission development, science instruments, mission

• Design and implement internet-based operations centers, enabling each university to control its satellite from a remote location

ION-F MissionION-F Mission

MissionMission

3CS

ION-F

USUSat

Dawgstar

HokieSat

Multiple Satellite

Deployment System

Configuration:

Scenario:

1 . Launc h

3 . Nanosat Deploym ent from M S DS

2. M SDS Deploym ent fromShuttle O rbite r

4. Individual Nanosat deployment

MSDS: Multi- Satellite Deployment System

Separation ScenariosSeparation Scenarios

T4T1 = TSafe, All Systems ExceptRecontact Hazards

= 20 minutes

= 0:00 T3 = T SEP

= T0 + 96 hours, 4 secs

= TSEP, Nanosat

Stack separation signalreleases both stacks

Intersatellite separationMSDS is 20 minutes outfrom Orbiter,timers

time-out

T0

Safety inhibits removedfor all MSDS systems

without recontacthazards.

Safety inhibits removedfor Nanosat systems

without recontacthazards.

MSDS released fromOrbiter/SHELS

MSDS timers initiatedRecontact hazard inhibits

removed aboardNanosats

Recontact hazard inhibitsremoved aboard MSDS

T2 = TSafe,Recontact Hazards

= T0 + 96 hours

INHIBITS STATUS MSDS AND NANOSAT

RecontactHazards

All othersystems

In-place

In-place

In-place

Removed

Removed

Removed Removed

Removed

Removed

Removed

= T0 + 102 hours, 4 secs

T4T1 = TSafe, All Systems ExceptRecontact Hazards

= 20 minutes

= 0:00 T3 = T SEP

= T0 + 96 hours, 4 secs

= TSEP, Nanosat

Stack separation signalreleases both stacks

Intersatellite separationMSDS is 20 minutes outfrom Orbiter,timers

time-out

T0

Safety inhibits removedfor all MSDS systems

without recontacthazards.

Safety inhibits removedfor Nanosat systems

without recontacthazards.

MSDS released fromOrbiter/SHELS

MSDS timers initiatedRecontact hazard inhibits

removed aboardNanosats

Recontact hazard inhibitsremoved aboard MSDS

T2 = TSafe,Recontact Hazards

= T0 + 96 hours

INHIBITS STATUS MSDS AND NANOSAT

RecontactHazards

All othersystems

In-place

In-place

In-place

Removed

Removed

Removed Removed

Removed

Removed

Removed

= T0 + 102 hours, 4 secsT4T1 = TSafe, All Systems ExceptRecontact Hazards

= 20 minutes

= 0:00 T3 = T SEP

= T0 + 96 hours, 4 secs

= TSEP, Nanosat

Stack separation signalreleases both stacks

Intersatellite separationMSDS is 20 minutes outfrom Orbiter,timers

time-out

T0

Safety inhibits removedfor all MSDS systems

without recontacthazards.

Safety inhibits removedfor Nanosat systems

without recontacthazards.

MSDS released fromOrbiter/SHELS

MSDS timers initiatedRecontact hazard inhibits

removed aboardNanosats

Recontact hazard inhibitsremoved aboard MSDS

T2 = TSafe,Recontact Hazards

= T0 + 96 hours

INHIBITS STATUS MSDS AND NANOSAT

RecontactHazards

All othersystems

In-place

In-place

In-place

Removed

Removed

Removed Removed

Removed

Removed

Removed

= T0 + 102 hours, 4 secs

T4T1 = TSafe, All Systems ExceptRecontact Hazards

= 20 minutes

= 0:00 T3 = T SEP

= T0 + 96 hours, 4 secs

= TSEP, Nanosat

Stack separation signalreleases both stacks

Intersatellite separationMSDS is 20 minutes outfrom Orbiter,timers

time-out

T0

Safety inhibits removedfor all MSDS systems

without recontacthazards.

Safety inhibits removedfor Nanosat systems

without recontacthazards.

MSDS released fromOrbiter/SHELS

MSDS timers initiatedRecontact hazard inhibits

removed aboardNanosats

Recontact hazard inhibitsremoved aboard MSDS

T2 = TSafe,Recontact Hazards

= T0 + 96 hours

INHIBITS STATUS MSDS AND NANOSAT

RecontactHazards

All othersystems

In-place

In-place

In-place

Removed

Removed

Removed Removed

Removed

Removed

Removed

= T0 + 102 hours, 4 secs

Multiple Satellite Deployment Multiple Satellite Deployment System (MSDS) System (MSDS)

T4T1 = TSafe, All Systems ExceptRecontact Hazards

= 20 minutes

= 0:00 T3 = T SEP

= T0 + 96 hours, 4 secs

= TSEP, Nanosat

Stack separation signalreleases both stacks

Intersatellite separationMSDS is 20 minutes outfrom Orbiter,timers

time-out

T0

Safety inhibits removedfor all MSDS systems

without recontacthazards.

Safety inhibits removedfor Nanosat systems

without recontacthazards.

MSDS released fromOrbiter/SHELS

MSDS timers initiatedRecontact hazard inhibits

removed aboardNanosats

Recontact hazard inhibitsremoved aboard MSDS

T2 = TSafe,Recontact Hazards

= T0 + 96 hours

INHIBITS STATUS MSDS AND NANOSAT

RecontactHazards

All othersystems

In-place

In-place

In-place

Removed

Removed

Removed Removed

Removed

Removed

Removed

= T0 + 102 hours, 4 secs

T4T1 = TSafe, All Systems ExceptRecontact Hazards

= 20 minutes

= 0:00 T3 = T SEP

= T0 + 96 hours, 4 secs

= TSEP, Nanosat

Stack separation signalreleases both stacks

Intersatellite separationMSDS is 20 minutes outfrom Orbiter,timers

time-out

T0

Safety inhibits removedfor all MSDS systems

without recontacthazards.

Safety inhibits removedfor Nanosat systems

without recontacthazards.

MSDS released fromOrbiter/SHELS

MSDS timers initiatedRecontact hazard inhibits

removed aboardNanosats

Recontact hazard inhibitsremoved aboard MSDS

T2 = TSafe,Recontact Hazards

= T0 + 96 hours

INHIBITS STATUS MSDS AND NANOSAT

RecontactHazards

All othersystems

In-place

In-place

In-place

Removed

Removed

Removed Removed

Removed

Removed

Removed

= T0 + 102 hours, 4 secs

T4T1 = TSafe, All Systems ExceptRecontact Hazards

= 20 minutes

= 0:00 T3 = T SEP

= T0 + 96 hours, 4 secs

= TSEP, Nanosat

Stack separation signalreleases both stacks

Intersatellite separationMSDS is 20 minutes outfrom Orbiter,timers

time-out

T0

Safety inhibits removedfor all MSDS systems

without recontacthazards.

Safety inhibits removedfor Nanosat systems

without recontacthazards.

MSDS released fromOrbiter/SHELS

MSDS timers initiatedRecontact hazard inhibits

removed aboardNanosats

Recontact hazard inhibitsremoved aboard MSDS

T2 = TSafe,Recontact Hazards

= T0 + 96 hours

INHIBITS STATUS MSDS AND NANOSAT

RecontactHazards

All othersystems

In-place

In-place

In-place

Removed

Removed

Removed Removed

Removed

Removed

Removed

= T0 + 102 hours, 4 secs

T4T1 = TSafe, All Systems ExceptRecontact Hazards

= 20 minutes

= 0:00 T3 = T SEP

= T0 + 96 hours, 4 secs

= TSEP, Nanosat

Stack separation signalreleases both stacks

Intersatellite separationMSDS is 20 minutes outfrom Orbiter,timers

time-out

T0

Safety inhibits removedfor all MSDS systems

without recontacthazards.

Safety inhibits removedfor Nanosat systems

without recontacthazards.

MSDS released fromOrbiter/SHELS

MSDS timers initiatedRecontact hazard inhibits

removed aboardNanosats

Recontact hazard inhibitsremoved aboard MSDS

T2 = TSafe,Recontact Hazards

= T0 + 96 hours

INHIBITS STATUS MSDS AND NANOSAT

RecontactHazards

All othersystems

In-place

In-place

In-place

Removed

Removed

Removed Removed

Removed

Removed

Removed

= T0 + 102 hours, 4 secs

Leader / Follower FormationLeader / Follower Formation

Orbit Ground Track

Same Ground Track FormationSame Ground Track Formation

Orbit Ground Track

• Isogrid Structure• Composite Side Panels

– 0.23” isogrid– 0.02” skins

DesignDesign

HokieSat• 18.25” (~ 45 cm) major

diameter hexagonal prism• 12” tall (30 cm) • 39 lbs (~18 kg)

Data Port

Crosslink Antenna

Uplink Antenna

Downlink Antenna

SciencePatches

LightBand

GPS Antenna

Pulsed PlasmaThrusters

Solar Cells

Camera

External ConfigurationExternal Configuration

Torque Coils (3)

Rate Gyros (3)

Downlink Transmitter

Cameras

Camera

Electronics Enclosure

Battery Enclosure

MagnetometerCamer

a

PowerProcessing Unit

Crosslink Components

Pulsed PlasmaThrusters (2)

Internal ConfigurationInternal Configuration

VT Structures OverviewVT Structures Overview

Panel 6 Panel 5 Panel 4

Panel 1 Panel 2 Panel 3

Nadir/Zenith Panel

HokieSat StructureHokieSat Structure

•Description: Nadir and Zenith

•Heritage: None

•Manufacturer: In-House/Techsburg

•Properties: Al 6061 T-6, Class 3 Irridite (MIL-C-5541-E)

•Mass: 1.70 lbm (0.773 kg)

•Status: Prototype Complete

I O N - FUtah State University - University of Washington - Virginia Tech

Top View of End Panel

Al 6061 T-651

Class 3 Irridite

AA21301-DWG02-1

1 of 1

Rabin, D. 18/02/01

FCTBD

0.010"0.005" 0.5°

To

p V

iew

of E

nd

Pan

el

1 o

f 11

18/02/01

1.70 lb 1 : 4

Ø0.190x3 Thru

HardwareHardware

COMPONENT MASS lbm (kg) QUANTITY DESIGN MARGIN (10%) SOURCEIsogrid Side 1 1.13 (0.514) 1 0.113 (0.0514) MeasuredIsogrid Side 2 1.13 (0.514) 1 0.113 (0.0514) MeasuredIsogrid Side 3 1.12 (0.509) 1 0.112 (0.0509) MeasuredIsogrid Side 4 1.13 (0.514) 1 0.113 (0.0514) MeasuredIsogrid Side 5 1.12 (0.509) 1 0.112 (0.0509) MeasuredIsogrid Side 6 1.14 (0.518) 1 0.114 (0.0518) MeasuredSkin Side 1 0.246 (0.112) 1 0.0246 (0.0112) AutoCADSkin Side 2 0.25 (0.114) 1 0.025 (0.0114) AutoCADSkin Side 3 0.247 (0.112) 1 0.0247 (0.0112) AutoCADSkin Side 4 0.242 (0.110) 1 0.0242 (0.0110) AutoCADSkin Side 5 0.247 (0.112) 1 0.0247 (0.0112) AutoCADSkin Side 6 0.247 (0.112) 1 0.0247 (0.0112) AutoCADEnd Panel 1.7 (0.773) 2 0.17 (0.0773) MeasuredBracket 1 0.0519 (0.0236) 1 0.00519 (0.00236) MeasuredBracket 2 0.0160 (0.00727) 1 0.0016 (0.000727) MeasuredBracket 3 0.0127 (0.00579) 1 0.00127 (0.000579) MeasuredFasteners 0.008 (0.00364) 82 0.00008 (0.000364) MeasuredLightband 1.76 (0.800) 1 0.176 (0.0800) PSCHoneycomb 0.510 (0.232) 1 0.051 (0.0232) AutoCADEpoxy 0.487 (0.221) 1 0.0487 (0.0221) Estimated

Total Mass = 16.6 lbm (7.57 kg)Total Mass = 16.6 lbm (7.57 kg)

MassMass

Total Mass = 118.8 lb (54 kg)

Mass Breakdown (Stack)Mass Breakdown (Stack)

PropulsionPropulsion

• Propulsion subsystem requirements

• Schematic• VT thruster arrangement• System parameters• Operations summary

Propulsion Subsystem Propulsion Subsystem RequirementsRequirements

• Provide thrust required for the formation flying mission (phase 1)– 22 m/s V required

• Orbit raising to extend life (phase 2)– Remaining propellant

• Augment torque coils for yaw attitude control

Top View

12

3

4

VT Thruster ArrangementVT Thruster Arrangement

SchematicSchematic

Anode

Cathode

Ultem Isolator

Mica-paper / FoilCapacitor

Teflon Fuel Bar

Spring

Ultem 2300 Thruster Assembly

Boron NitrideInsulator

Thruster mount

System ParametersSystem Parameters

Translational DV (m/s) 54Rotational DV (m/s) 54Specific Impulse (s) 485Impulse Bit (mNs) 56Thrust - 1 Hz Fire Rate (mN) 56

Power

Component Orbit Ave Power (W)

Peak Power

(W)

Voltage (V)

Propulsion System

0.65 13 28

• Structural– 4 thruster nozzle holes, sized and placed as defined in

drawings– 2 thruster mounts, attached directly to isogrid nodes

• Power– Requires 13 watts at 28 volts for translation – System can tolerate a decrease in voltage to 16.5 volts – No power required when system not in use– Approximate duty cycle:

• 3% for formation keeping

• 10% for formation maneuvering

InterfacesInterfaces

Solar CellSolar Cell

• Tecstar Triple-Junction 24% Cascade cells

• Heritage on DS-1, MightySat, SMEX, TRACE, others

• Cell Dimensions: 2.497” x 1.522” (6.25 x 3.75 cm)

• 0.030” spacing between cells

• Cells supplied kitted

– Cover glass

– Diode on each cell

– Interconnects

Composite structure comprised of 0.23” isogrid and 0.02” skin

FabricationFabrication

Strength & stiffness test of structure without skin panels

Strength & stiffness test of loading fixture

Static TestingStatic Testing

Strength & stiffness test of structure with skin panels

• Experiment demonstrated a 32% gain in stiffness in the cantilever mode due to

addition of skins• Skins added less than 8% to the total mass

Static TestingStatic Testing

Modal (tap) Testing of Side Panels

• Hammer provides impulsive input• Accelerometer measures

accelerations used to characterize natural frequencies

• Tap testing with and without skins• Verification of predictions of finite

element analysis

Dynamic TestingDynamic Testing

Up-Link Antenna PicturesUp-Link Antenna Pictures

Clean Room PicturesClean Room Pictures

•Air Force Research Laboratory•Air Force Office of Scientific Research•Defense Advanced Research Projects Agency•NASA Goddard Space Flight Center•NASA Wallops Flight Facility Test Center•University of Washington•Utah State University•Virginia Tech•Professor A. Wicks•Professor B. Love•Members of ION-F

AcknowledgementsAcknowledgements

AFOSR Goddard Space Flight Center STP

Defense Advanced Research Projects Agency