aiaa panel on small, distributed, fractionated spacecraft 1 long beach, ca sept. 18, 2007...

AIAA Panel on Small, Distributed, Fractionated Spacecraft 1 Long Beach, CA Sept. 18, 2007

• Introduction

• THEMIS Overview

• Lessons Learned

• Importance of a Micro-Sat Program

THEMIS:An Example of

a Cost-Effective Mission ofSmall, Distributed, Fractionated

Spacecraft, a Pathfinderfor a Micro-Sat Program

Vassilis Angelopoulos, UCLAWith contributions from:

Peter R. Harvey, Ellen R. Taylor, Greg Delory, SSL/UCBMichael J. Cully, Warren Chen, Kevin Brenneman, ATK Space

And an incredible THEMIS team!


Maximizing Substorm Science on THEMIS:Probe Alignments

Vassilis Angelopoulos,UCLA ESS April 13, 2006

Simulation: J. Raeder, UNH

Visualization: Tom Bridgman,GSFC/SVS


Mission overview

Instrument I&TUCB

Mission I&TUCB-JPL

Encapsulation

& launch

BGS

OperationsUCB

Probe instruments:ESA: Thermal plasmaSST: Super-thermal plasmaFGM: Low frequency magnetic fieldSCM: High frequency magnetic fieldEFI: Electric field

Ground

SST

ESA

EFIa

EFIs

FGM

SCM

Tspin=3s

Release

D2

925

-10

@ C

CA

S

Bus I&TATK


Modular Science-craft Design

• Power positive in all attitudes • Passive thermal design• Passively spin stable under all

deployment conditions• S-Band COM system always in view

of earth every orbit at nominal attitude. In view for greatest part of orbit in any attitude

• Mono-propellant blow-down RCS (propulsion) system is self balancing on orbit

• Modular tanks, instruments, panels• Highly integrated bus and instruments:

thermally, mechanically, electrically and electronically


Standard Delta 10 ft. Fairing Static Envelope

3712 PAF

Probe Carrier Assembly (PCA = 5 Probes + Probe Carrier) on L/V

Probe Carrier Assembly (PCA = 5 Probes + Probe Carrier) on L/V

THEMIS Launch Configuration

THEMIS Launch Configuration

Probe Carrier Assembly (PCA) on Delta 3rd StageProbe Carrier Assembly (PCA) on Delta 3rd Stage

Launch Configuration

• Dedicated launch accommodated within standard Delta 7925-10 vehicle configuration and services

• 10’ Composite Fairing required to accommodate five Probes on the Probe Carrier in the “Wedding Cake” configuration

• PC stays attached to Delta 3rd stage after probe dispense

• Each probe dispense from the PCA is coordinated with but independent of the other probes

• No single probe anomaly precludes dispense of remaining probes

Star 48 3rd Stage


Production Line Approaches: Development and Instrument I&T

EFI Instrumentproduction Bus production

Instrument Integration: assembly line


First round: F2 VibXYJPL: 144-100 April-May, 2006

Second Round: PCA VibXYJune 25 – Aug 16, 2006

Production Line Approaches: Environmental testing at JPL in 2 rounds

First Round:F2 Thermal Balance/T-Vac

Second Round:Two-at-a-time mini TB/TV


Launch Processing:Round-robin w/ one primary EGSE

Spin Balance Dry Weigh & Pressurize Final checks

PCA Integration

Transportation to Pad 17B: Feb

33rd stage mating


Successful mission attributes:It’s a small team of happy people!


The Feat:Outstanding Science at Reasonable Cost

THEMIS is now poised to resolve themystery of substorms in its prime missionin January-April 2008, as proposed.

THEMIS came at a cost of $0.1B compared to $1-2B for similarspace physics missions in the past (Cluster) and future (MMS). How?

THC

THE

THDTHB

THA

the 1st Substorm

…was captured by THEMIS

On March 23, 2007


Successful multi-probe mission attributes:Small satellites with modular design

Small satellites:Enforce small team mentality (too many cooks spoil the broth)

“Projectized”, lean team, operating efficientlyConsists of multi-talented, multi-tasking individuals

Modular satellite design:Ensures clear interfaces and clear team organizationFacilitates parallel development, and I&T process

Small and modular both facilitate production line approach:First probe needn’t be completely error-free for line to benefitMost important benefit is schedule, comes from staggeringOther benefits:

Reduces errors (same person does same thing)Increases productivity and quality (twice the time to do 5)Corrections forwards and backwards are more robust


The importance of a Micro-satellite program

Scientific problems requiring constellations of small satellites abound. We are only now beginning to explore the wavenumber domain of space plasma interactions. There are very few missions like THEMIS to learn from. A line of micro-sat launches can provide a much needed test-bed for Small Distributed Fractionated Spacecraft.

Why micro?Launch is easier, task/schedule smaller

Why a program?Continuity ensures heritage in core teamsCan be modeled after NASA’s rocket program

Benefits: Rapid Science DiscoveriesContinuous Instrument Development for New CapabilitiesEducation / Workforce DevelopmentFeeds Into Larger Missions / Indirect Science Discovery

aiaa panel on small, distributed, fractionated spacecraft 1 long beach, ca sept. 18, 2007...

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