All-Electric CubeSat Propulsion Technologies · PDF fileApproved for public release;...

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All-Electric CubeSat Propulsion Technologies

6th International Interplanetary CubeSat Workshop

May 31st 2017

Dan CourtneyMichael Tsay

Nathaniel Demmons

Approved for public release; distribution is unlimited. Copyright May 2017. 2

Busek Co. Inc.

A History of Innovation and Space Flight

Largest Staff in the Industry devoted to Electric

Propulsion

Five propulsion technologies; design, development,

manufacture in-house

Close cooperation with universities ISO 9001:2008 and AS9100C certified

Registered Manufacturer and Exporter

with the US Dept. of State/DDTC

HOW WELL WE DO IT …

• Established the Domestic Hall Thruster Industry

• First US designed/built Hall thruster in space

• First micro-pulsed plasma thruster in space

• First flight-demonstrated electrospray thrusters

• First iodine fueled Hall thrusters & Ion engines

WHAT WE DO

• Engines for Spacecraft

• Compact Power Electronics

• Space Environment Testing

• Terrestrial R&D


Missions: Past and Present


Busek CubeSat Propulsion Systems

BmP-220: Micro Pulsed Plasma

• No moving parts, valves

• No pressure vessel

• Teflon propellant

• Low Power

• System volume <1/3U

BET-100: Mini Electrospray

• Passive feed

• No pressure vessel, valves

• Low Power

BIT-3: 3 cm Micro RF Ion

• No internal cathode

• Tested up to 3,500s Isp

• Iodine compatible

BGT-X5 System: 1U/0.5N

Green Monoprop

• High thrust (high

acceleration)

• High density Isp

• Low-toxicity propellantBHT-200: 200W Hall Effect

• Flight heritage

• High thrust-to-power

• Suitable for MicroSats

Compatible with 3U or 6U CubeSats

Compatible with >12U CubeSats


Busek BIT-3 RF Ion Thruster

• Unprecedented performance per volume

– Up to 2.9km/s deltaV for 6U/14kg CubeSat

– >35kNs total impulse

– 1.6U system envelope

– 3.0kg wet, 1.5kg propellant loading

– 0.66-1.24mN thrust and 1,400-2,640sec Isp (56-80W throttleable system input )

• 2-axis, ±10o gimbal integrated to thruster

• Volume efficient, conformal iodine tank

– Lightweight, 22.5psig proof pressure

• Rad-tolerant, miniaturized PPU

– 28V regulated input, RS-485 comm

– SOA, 90% efficiency RF power generators

– “Rad-Hard Fence” providing 37MeV SEU immunity

• 80W power draw fits within capability of SOA solar arrays (120W for 6U)

Thruster

Cathode

Prototype BIT-3 Thruster Firing on I2


0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

28 30 32 34 36 38 40 42 44 46 48 50 52

Measu

red

Th

rust,

mN

Measured Thruster Head Power (Not System Input Power), W

Xe I2

Busek BIT-3 RF Ion Thruster Performance

Xe vs. I2 Thrust Comparison per Thruster Head Power

Latest BIT-3 System Performance (Calculated)

y = 0.0242x - 0.6968

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

56 58 60 62 64 66 68 70 72 74 76 78 80

Th

rust,

mN

Est. PPU Input Power within Throttleable Range, W

y = 51.6700x - 1,487.1953

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

56 58 60 62 64 66 68 70 72 74 76 78 80

To

tal

Isp

, sec

Est. PPU Input Power within Throttleable Range, W

Prototype BIT-3 Thruster Firing on Xe

Adaption of Iodine Technology by Busek’s Mini RF Ion Thrusters (Engines)

• Iodine stored as a solid low pressure, high density propellant storage

• The BIT series thrusters (1-7cm sized) are inherently iodine compatible

• The 3cm BIT-3 thruster is the world’s first gridded ion thruster using iodine

Prototype BIT-3 Thruster Firing on I2


Busek BIT-3 RF Ion Thruster Mission Applications

6U/14kg Lunar IceCube in Stowed and

Flight Configurations

BIT-3 System Enables New Mission Concepts via High ΔV

Two lunar missions, to be launched via NASA EM-1 (SLS, 2019)

• Busek BIT-3 RF to achieve lunar capture and science orbits

• 6U CubeSats

Lunar IceCube

• Morehead State University

• Detection of water / other volatiles from LLO

LunaH-Map

• Arizona State University

• Detection of hydrogen (water)

BIT-3 entering CDR for flight hardware deliveries end of CY17

Img: NASA, D. Folta


NASA/JPL Disturbance Reduction SystemFlown on ESA LISA Pathfinder mission

• Technology demo for future gravity wave mission

• Delivered 2008, launched 2015,

• On-orbit success, >1500hrs/thruster

8 Busek systems in total

Null disturbances

• Maintain spacecraft position to test masses

Required to hold position <10 nm/Hz1/2

Busek Electrospray Thrusters Aboard LISA Pathfinder

Img: NASA/JPL

Other Missions• Comet ‘crumb’ detection

• Full LISA missionImg: NASA/JPL


Busek’s BET-100 and BET-300-P Passive Thrusters

Fully integrated, unpressurized propellant supply

Low power, highly variable thrustCompact / high performance

thrusters for CubeSats

BET-100

Precision thrust control

• <5 to 65μN @ 1μN resolution

• Closed loop thrust control via PPU

Compact 0.5U system

• Fully integrated propellant reservoir

• Unpressurized propellant tank

• 50Ns+ total impulse

Low power, <6W max. system power

Under development

• Qual. Testing Q2 2017

• Flight in 2018 on 6U AMES Pathfinder

Highly scalable technology

• BET-300-P thruster head

• Directly measured 300μN @ <6W

Modular/distributable form factor

In active development

• Presently at TRL 3

9.5cm

4.3cm


Electrospray Thrusters as a Precision CubeSat RCS

Compare with reaction wheels

~0.5uNm resolution

Mech. jitter > 10mNm

Passive Electrospray Thrusters as Precision RCS

• 100’s of nN resolution; 10’s of nNm torque on CubeSats

• Stable output, no sources of mechanical vibration

• Highly throttleable

• Precision low thrust maneuvers and fast slews

• Slew a 6U S/C through 180o in minutes

• Numerous applications:

• Pointing for observations, laser comms…

• Formation flights, disturbance reduction

Small Form Factor Retains LISA-Proven High Precision

e.g. 6U S/C


Applications to CubeSat Attitude Control : Example Mission Scenario

6U CubeSat observatory tasked with taking long exposure inertial-stare images

• Precision ACS via electrospray holds target centroid to sub-arcsec

(w/appropriate feedback sensor) over 10’s of seconds

• Same ACS used to slew to next image positionImages 100/day

Impulse /image 1.7mNs/img

Impulse /year 125Ns/yr

Margin 100%

Total impulse 250Ns/yr

Mprop @ 1650s Isp 15g/yr

Mprop @ 65s Isp

(e.g. cold-gas)

400g/yr

High Isp, highly throttleable electrosprays could serve as sole ACS


Applications to Small Spacecraft Trajectory Control: Formation Flight

Circular relative motion example

Precision Formation Flight

• Maintain static or dynamic separation in LEO or beyond earth

• Offset environmental disturbances


Busek All-Electric Propulsion Systems for CubeSats

BIT-3 system

• Advancing towards TRL-6 in 2017

• High impulse density ~20kNs/U

• Thrust up to 1.24mN

• Iodine propellant

• Compact, low pressure tanks

• Scheduled for two 6U lunar missions launched via EM-1

Busek Electrospray Thrusters

• Unique precision trajectory and attitude control capabilities

• Extremely quiescent, no moving parts

• Applications to precision pointing, formation flight, disturbance compensation…

• BET-100uN

• Highly throttleable precision thrust from <5 to 65μN

• Fully integrated, unpressurized propellant supply

• Advanced PPU with thrust control

• Scheduled for flight on NASA Ames Pathfinder Tech. Demonstrator, 2018

• Upcoming developments

• Scaled up thrust up to 300μN demonstrated

• Compact, multi-axis system architecture


Facilities


Thruster Space Qualification and Simulation Chambers

T4 T6

T8 T18 T8T6 T9


Acceptance Testing, Manufacturing and Assembly

Designation Area (SF) Image Certification Function/Major Equipment

CR-1

Microfluidics200

ISO-8

(Class 100,000)

Used for assembly of electrosprays/flight HW. Contains an

ISO-5 laminar flow hood for enhanced cleanliness

operations'. Propellant drying station, various special tools,

microfluidic diagnostics. Nikon SMZ-10 stereoscopic

microscope with fiber-optic illumination, Olympus BH2

binocular microscope with video output, GR-202 laboratory

balance, 0.0001g resolution and 104X ultrasonic cleaner

CR-2

Metrology

Welding

Specialty Operations

300ISO-8

(Class 100,000)

Used for incoming parts inspection w/ CMM & optical 3D

microscope. Assembly, calibration, testing of micro-valves.

Contains orbital & laser welder, inductive brazing unit,

optical particle counter, and xenon loading cart

CR-3

Assembly

Integration & Test

1,000ISO-8

(Class 100,000)

Used for assembly, integration and testing of major flight

HW. Contains electronic GSE, instrumentation, test

benches, overhead gantry. 100 SF parts cleaning annex

accessible from within CR3, automated 3-axis transition 3-

axis magnetic probe

Designation Area (SF) Image Certification Function/Major Equipment

CR-1

Microfluidics200

ISO-8

(Class 100,000)

Used for assembly of electrosprays/flight HW. Contains an

ISO-5 laminar flow hood for enhanced cleanliness

operations'. Propellant drying station, various special tools,

microfluidic diagnostics. Nikon SMZ-10 stereoscopic

microscope with fiber-optic illumination, Olympus BH2

binocular microscope with video output, GR-202 laboratory

balance, 0.0001g resolution and 104X ultrasonic cleaner

CR-2

Metrology

Welding

Specialty Operations

300ISO-8

(Class 100,000)

Used for incoming parts inspection w/ CMM & optical 3D

microscope. Assembly, calibration, testing of micro-valves.

Contains orbital & laser welder, inductive brazing unit,

optical particle counter, and xenon loading cart

CR-3

Assembly

Integration & Test

1,000ISO-8

(Class 100,000)

Used for assembly, integration and testing of major flight

HW. Contains electronic GSE, instrumentation, test

benches, overhead gantry. 100 SF parts cleaning annex

accessible from within CR3, automated 3-axis transition 3-

axis magnetic probe


Selected Customers

Busek is proud to serve a variety of academic, government and commercial

customers in the U.S. and abroad.

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