Ion engine for Small Spacecraft › lecture › Chap9(Microsatellite...Propulsion and Energy Systems; Dec 21st (2015) Concept by Univ. Surrey for 3U-cubesat Propulsion module: ¼U

Propulsion and Energy Systems; Dec 21st (2015)

Micro-satellite propulsion KOIZUMI Hiroyuki

(小泉宏之)

Graduate School of Frontier Sciences, Department of Advanced Energy

& Department of Aeronautics and Astronautics

(基盤科学研究系先端エネルギー工学専攻，工学系航空宇宙工学専攻兼担)

Huge cost

Failure is never excused

Conservative and long-time design

No growth of technology and human

Compensation by money ant time

Small satellite

・Welcome, new service

・Quick technology cycle

Innovation

・Quick human-resource development

Small satellite

Small satellites

Microsatellites

Nanosatellites

100 – 500 kg

10 – 100 kg

1 – 10 kg

Cubesat Unit: 10 x 10 x 10 cm3

Mass

Power

Typically 10 – 20% of the satellite mass

Typically If parallel to the mission: < 20% If dependent from the mission: < 80%

Typical power generation： 1–3 W/kg （e.g 10 kg satellite → 10–30 W）

Small propulsion; Resource

Typical budget for propulsion would be 10-20%

Budget

Law Strict limitation for High-pressure gas, explosives, toxic materials.

Small propulsion; Resource

Don’t lose the merit of small sat.

LEO; 100km altitude change 60 m/s

LEO 300km, 1-year drag compensation （50kg, 50cm x 50cm, CD1.4）

50 m/s

GEO; NSSK (1year) 50 m/s

LEO; 1 degree orbit inclination 130 m/s

Lunar orbit from GTO 2000 m/s

ΔV

Small Chemical Propulsion

・Cold-gas thruster ・Gas-liquid equilibrium thruster ・mono-propellant propulsion using hydrogen peroxide ・Micro-solid array ・Solid microthruster

Cold-gas thruster


Cold-gas thruster；Principle

gcCI Fsp /*

Blow-down from a high pressure tank

Specific impulse by gas and temperature

M/kg mol-1

Density (24 MPa)

Isp/s

He 4 0.04 180

N2 28 0.28 80

Xe 131 2.74 31

Resisto-jet thruster

Heater


Cold-gas thruster

The simplest

Already used in micro-/nanosatellites

Low specific impulse

Large high-pressure system

Not for high ΔV

Merit

Demerit

Heritage


1) SSTL; Gas Propulsion System

Dry mass: 6.7 kg Dimensions: 400 x 254 x 215 mm3

Propellant: 500g Xe or 176g N2 Thrust: 20 – 50 mN Isp : 42 s Xe or 100 s N2 Total impulse: 380 Ns

50 kg S/C

ΔV = 6.4 m/s


Cold-gas thruster

Dry mass: 7.3 kg

Propellant: 12 kg Xe Thrust: 18 mN Isp : 48 s Total impulse: 5644 Ns

SSTL; Microsatellite Gas Propulsion System

50 kg S/C

ΔV = 110 m/s

For ΔV of ～100 m/s?

Gas-liquid equilibrium thruster


Gas-liquid equilibrium thruster

One of the gold-gas thrusters

Propellant storage in liquid phase

No high pressure system

→Reducing system volume

Needing a heater for vaporization

Needing a gas/liquid separation device

Specific impulse is the same as cold-gas thruster

Merit

Demerit


1) Thruster for IKAROS

Propellant: 20 kg HFC-134a Dry mass: 約20 kg Thrust：400 mN Isp：40 s Total impulse: 7000 Ns

Molecular mass：102 g/mol Vapor pressure: 0.57 MPa Liquid density: 1225 kg/m3

No high-pressure system

Metal foam for the separation

using surface tension and temperature gradient

Mono-propellant thruster


Hydrogen peroxide thruster

Hydrogen peroxide + catalyst

→Isp: 80 s

Propellant feeding →Bladder + High-pressure gas

Propellant tank×２＋Pressure tank ×１


Thruster for Hodoyoshi-1/3

Power 3.4W

Mass 5.8kg, including 2 kg propellant

Size 265×270×85 mm3

Thrust 350 mN

Isp >80 s

ΔV 30m/s

Thruster for Hodoyosh-3


Hydrogen peroxide thruster

High Isp as CP

Hodoyoshi-1/3

Toxity of H2O2

Rejected for H2A secondary payload (UNIFORM1)

Merit

Demerit

Heritage

Needing on-site charge

Solid-propellant thruster


Micro-solid array

Digital control of micro-solid propellant

MEMS fabrication Micro Electro Mechanical Systems using semiconductor device fabrication technologies


マイクロソリッドアレイ

Small ΔV

Ultra miniaturization without gas system

e.g. 30 μNs by 1shot

300 mNs by 100x100 array

ΔV = 0.3 m/s @ 1kg S/C

長所

短所

Easy fabrication of arrayed structure


Laser ignition, solid microthruster

Boron & potassium nitrate

Laser ignition of multiple pellets


Laser ignition, solid microthruster

Isp:150s, 60 shots, 300-cc

Cubesat compatible 10 m/s class ΔV

ΔV : 30 m/s for a 3kg Cube-sat

Merit

Demerit ΔV less than 100 m/s

Needing rotating mechanism

Small Electric Propulsion

・Pulsed plasma thruster ・Vacuum arc thruster ・Arc-jet thruster ・Ion thruster ・Electrospray ・Microwave engine ・Hollow cathode thruster

Pulsed Plasma Thruster


Pulsed plasma thruster

Solid propellant (not explosive), passive feed

Pulsed discharge of capacitor energy

Electromagnetic acceleration


パルス型プラズマスラスタ；特徴

Simple feeding mechanism

EMI (electro magnetic interference)

Geometric limitation of propellant and ΔV

Several verifications

Component life time of 1 billion shots

Merit

Demerit

High specific impulse（500-1000 s）

Heritage


Thruster on EO-1

EO-1 by NASA Launch: 2000 Mass: 570 kg

Impulse bit: 0.86 mNs Isp：1370 s Power：70 W (1Hz) Total mass: 4.95 kg Propellant: 0.14 kg Total impulse: 460 Ns →ΔV = 0.81 m/s

←!!

Spacecraft

Propulsion


Concept by Univ. Surrey

for 3U-cubesat

Propulsion module: ¼U Pulsed power module: ¼U

Mass 0.34 kg

Power 1.5

Volume 480 cm3

Isp 320 s

Propellant 1.1 g

ΔV for 4.5 kg 2.7 m/s


PROITERES by OIT (大阪工大)

PROITERES

Launch by PSLV (Indian rocket) in 2012

10 kg, 30x30x30 cm3, 10 W

Coaxial pulse plasma thruster

Electrothermal acceleration, no feeding system Wet mass: 2.0 kg (Head:0.3kg, Cap.:0.2kg PPU:1.0kg, Cables:0.5 kg) Total impulse: 5 Ns（ΔV 0.5 m/s）


• Compatible from cubesat to 100 kg S/C

• High technical maturity

• Few actual usages, so far

• ΔV limitation • Electromagnetic interference

Pulsed plasma thruster; Summary

Ion thruster


Ion thruster

Plasma source Ion acceleration

electron emission

Propellant

Power

Ion

Electron

Neutral Inevitable electron emission

Electrostatic acceleration of ions


Ion acceleration

Ion beam

Outside

Inside

Example of the ion beam

Appropriately-designed grids system converges the ion beam

Beam trajectory

Electrostatic potential


Types of the plasma generators

• Direct current (DC) electron discharge

• Radio frequency (RF) discharge

• Microwave discharge


DC-discharge ion thruster

Electron emission

magnetic field

Anode 30 V

Gas injection


RF-discharge ion thruster

Induced magnetic field Insulating body

RF coil

Gas injection

Induced current

ICP


Microwave discharge ion thruster

Microwave emission

magnetic field

Gas injection

Antenna Coaxial cable or waveguide

Electron cyclotron resonance

𝑓microwave = 𝑓cyclotoron


Ion thruster

High Isp (1000-3000 s)

High-pressure tank and feeding system

Complicated = a number of parts

Merit

Demerit

Heritage

The most heritage in standard-size S/C Small ion thruster: Hodoyoshi-4, PROCYON

High ΔV mission Storage in a tank


μRIT by Univ. Giessen

The smallest thruster in RIT series

RF plasma

Developed for LISA

RIT for (four thruster heads)

Dry mass: 14 kg Propellant: 0.4 kg Xe Thrust: 7 – 100 μN Power: 60-86 W (PCU: 26 W)

Max. thrust 600 μN


Research by JPL & UCLA

DC-discharge, 30 mm of beam diameter Thrust：3.0 mN Specific impulse：1700 – 3200 s Ion production cost: 400 – 600 V/ion *not included the neutralizer DC-discharge = two cathodes Inside for plasma Outside for neutralizer


Research by KU (九州大学)

Microwave discharge (μ10’s neutralizer based plsma source)

Thrust 790 μN Isp 4100 s Microwave power 8 W Beam power 20 W

システムには45W必要 (8/0.4 + 20/0.8)

*not included the neutralizer


Mass: 8.1 kg (incl. 0.9 kg Xe)

Volume: 39 x 26 x 15 cm3

Power: 27 W

Thrust: 210 μN

Isp: 740 s

Delta V: 140 m/s (50 kg S/C)

MIPS Flight Model

Performance summary

MIPS, flight model

Earth gravity assist

A small secondary payload of HAYABUSA-2

Flyby observation of a small asteroid

1. Wheel unloading by RCS

2. High ΔV for orbit transfer

3. Trajectory correction maneuver

Multiple thrusters

Electric propulsion

Chemical propulsion

PROCYON needs

©Google

Xenon-gas system

Ion thruster

Controller

Control

Gas

Power supplies Microwave

High voltages

MIPS Miniature Ion

Propulsion System

Xenon-gas system

Ion thruster

Controller

Control

Gas

Power supplies Microwave

High voltages

I-COUPS Ion thruster and COld-gas thruster

Unified Propulsion System

Cold-gas thrusters

Cold-gas thruster

Thrust (single) 22 mN

Specific impulse 24 s

Number of thrusters 8

Power consumption 7 W

(2 thrusters)

Cold-gas thruster Thruster valve

Cold-gas thrusters 0.41 kg

Controller 0.95 kg

Power supplies 1.31 kg

Ion thruster 0.38 kg

Gas system

4.5 kg !!

Xenon 2.57 kg

Sharing gas system is superior to increasing Isp

Gas system1 (Tank) 2.01 kg

Gas system2 (others) 2.25 kg

0

50

100

150

200

250

Accu

mu

late

d o

pera

tion

tim

e/h

ou

rs

I-COUPS; ITU全運転(5分平均プロット ) 論文用 from Dec 28 (2014) to Mar 12 (2015); 運転判定条件:SPS-I (mA)>1.00

Tota

l opera

ting t

ime/h

ours

223 h

©Hodoyoshi-3&4, The University of Tokyo

COTS-based micro-EP subsystems, including the high-pressure gas system, have been in good health.

The cold-gas-thruster RCS are successfully working over 103 operations

The ion thruster operated in 223 hours.

The miniature propulsion system of PROCYON has operated for more than 6 months, as the first interplanetary micropropulsion.


Iodine ion thruster by Busek

54

Thrust 600 μN Specific impulse 2000 s Power 30 W System Dry Mass 1.7 kg Propellant Mass 1.5 kg

Lunar Ice Cube; launch in 2018


• Studies are increasing, but fewer than PPT

• Few thrusters completed as a system

• UT launched/operated the first one, and may be followed by Busek.

• Xenon limits the dry mass as >3 kg

• The highest ΔV potential

Ion thruster; summary

Other Electric Propulsions


Microwave engine

Developed in Hokkaid Univ. (北海道大学)

μ10’s neutralizer based plasma source

= Double discharge, cusped field Hall effect thruster

Electrostatic acceleration, no grids

Endurance test

Components development for Hokkaido satellite (no information update)


Microwave engine

Including PPU eff.

18.5W

38.5W

57 W total power

T: 0.6 mN Isp: 1015 s


Small arc-jet thruster

Micro-Multi-Plasma-jet Array

Small arrayed nozzle by laser etching

Needing high pressure feeding system

Thrust 1.1 mN Power < 10 W Isp 70 s (N2)

by 3x3 array


Electrospray thruster

Emission of charged particles from liquid surface by strong electric field

liquid metal Oil Ionic liquid

FEEP

Isp depends on specific charge and mass

Colloid thruster

10,000 s 100 s 1000 s

MEMS, μm-needle → array

No plasma → High efficiency

～100 kV/mm


FEEP: Field Emission Electrostatic Prop.

In-FEEP: using Indium

LMIS (Liquid Metal Ion Source) is not a thruster but has a lot of space utilization heritage

Thrust：0.1 – 100 μN Isp: 5,800 s @ 25 μN Total Impulse: 6100 Ns Propellant: 15 g Indium

9 LMIS Assembly

Ultra-accurate attitude control


Vacuum-arc thruster

Surface discharge in vacuum

Propellant: electrodes ＋ insulator (dielectric material)

One type of the pulsed plasma thrusters

（using a capacitor, but not using an ignitor）

Merit/demerit is similar as PPT


Hollow cathode thruster

Hollow cathode（electron source）as thruster

Acceleration: electrothermal ＋ plasma potential

Merit: already developed for space utilization

Thrust 1.6 mN Power 55 W Isp 85 s

Needing high pressure

PPU: 260 x 86 x 23 mm3

Similar with resisto-jet


Microthruster

Motivation of small sat: Easy, Quick, Cheep

Motivation of small prop.の魅力: same

Abundant researches for microthrusters （more than standard sized propulsion）

Few flight heritage

Point 1: Don’t trust specific impulse

Point 2: Total system mass & power

Point 3: Check the sub-components

Check points for microthrusters


Specific impulse

Quite attaractive

Case 1) EP; Isp 3000s, Max Prop. 10 g, Dry M. 5 kg

Case 2) CP; Isp 30s, Max Prop. 1000 g, Dry M. 4 kg

Which is better? Both have the same wet mass, but Case 2 has shorter firing time

Total impulse is the most important

ITotal = Isp * g * MProp

Case 3) Isp 300 s, Max Prop. 1 kg, Dry M. 4 kg


System mass and power

No thruster operate without sub-components

System (total) mass and power are important

Thruster: 10g, Sub-component: 1 kg ??

Few direct drive by satellite bus voltage

Needing PPU (high vol.，DC→AC, etc）

High voltage supplies: 50-90% efficiency

Mcirowave ：20-40% efficiency

Gas-feeding system has dominant mass

Does it have a neutralizer?


Sub-components

e.g. ion thruster of HAYABUSA-1/2

Ion thruster by NEC (research by ISAS) Power and system assembling by NEC High-pressure system by MHI

Who is responsible for the microthruster?

Completeness of the subcomponents

Simple subcomponents are merits


Summary

No standard microthrusters

Important: non high-pressure and non toxic

S/C of >20 kg ΔV < 100 m/s → Cold-gas thruster

Pulsed plasma thruster

ΔV > 100 m/s → Ion thruster

S/C of <20 kg ΔV < 10 m/s → Pulsed plasma thruster

Solid microthruster

ΔV > 10 m/s → No candidate

My perspective:

Thank you

Ion engine for Small Spacecraft › lecture › Chap9(Microsatellite...Propulsion and Energy Systems; Dec 21st (2015) Concept by Univ. Surrey for 3U-cubesat Propulsion module: ¼U

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