Gossamer Systems for Satellite Deorbiting: The Cubesail and DEORBITSAIL Missions

Professor Vaios Lappas

University of Surrey

Space Vehicle Control Group Email: v.lappas@surrey.ac.uk

Presentation Contents

• Space at Surrey

• Space Debris:

• The problem

• Missions:

•Cubesail (2012/2013)

•DEORBITSAIL (2014)

• The Future

• InflateSAIL (2015)

•Gossamer DEORBITER (2015)

•Active Debris Removal Demonstration Mission (2016)

Introducing Surrey….

Surrey Space Centre: formed in 1979 at the University of Surrey, pioneering

microsatellites — now 90 academic researchers specialising in space engineering.

Surrey Satellite Technology Ltd: formed in 1985 by the University of Surrey, is a British

satellite manufacturing company; £40M revenues & 320 staff; SST-US in Denver, Co; EO

services (DMCii); launch services; recently acquired by EADS.

SSTL+SSC+ Astrium: achieving a synergy of academic research and commercial

exploitation

• “Pushing the Boundaries of Low Cost Small Satellite Applications and

Technologies”

• Training the next generation of space engineers, scientists,

entrepreneurs and business leaders

• Hands-on education and research using in-orbit assets

• Largest space engineering research group

The University of Surrey

SSC’s Ground-Station and Satellite Development Lab Surrey’s SNAP-1 6.5 kg Nano-Satellite (2000)

Space Debris, a problem? (Image - NASA)

The Problem: Space Debris

• Satellites with a completed service

• Launch vehicle upper stages remain in

space for years

– Some explode due to depleted tanks

• 5,500 tones of space debris in low earth

orbit

• Threat to:

– Space assets

– Astronauts/space stations

– Environment

• Space: Expensive Real-Estate

– Earth observation,

telecommunications, navigation

Image courtesy of ESA/ESOC

Debris on Earth

Current Issues: Envisat

Space Debris in LEO

Image courtesy of ESA/ESOC

Operational payloads

6%

Non-operational payloads

26%

Rocket bodies 18%

Mission-related objects

10%

Fragments 40%

Orbital Debris

Distribution

• Largest portion (2/3) of orbital debris is

concentrated in LEO

• Only 6% of Earth orbiting objects are operational

payloads

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Altitude Distribution in LEO

Orbital Debris Projection

• Liou, Johnson and Hill 2010, NASA/JSC

Debris Evolution

• Euroconsult forecast for next 10 years shows 400 out of 1200

anticipated launches will be in LEO – only includes satellites >

50kg

• NASA LEGEND study predicts non-linear growth for LEO

region if no mitigation is followed

• To have a sustainable LEO population requires:

• Implementation of commonly adopted mitigation measures

• Active Debris Removal (ADR) of 5 objects or more…

Satellite/Space Debris Evolution

ADR-Active Debris Removal

25 Year Deorbiting Requirement

• Orbital debris mitigation guidelines have been debated in great

detail in the space community.

• In February 2007 and after a multi-year effort the United

Nations' Committee on the Peaceful Uses of Outer Space

(COPUOS) adopted a set of space debris mitigation guidelines

which includes a 25 year deorbit requirement from LEO.

• The guidelines were accepted by the COPUOS in June 2007

and endorsed by the United Nations in January 2008.

• To become the law in many countries in Europe

Debris Removal/Mitigation

• Many proposed solutions

• Chemical propulsion

• Electric propulsion

• Electrodynamic tethers

• Drag augmentation

•Decrease velocity/altitude of debris and burn up safely in

the earth’s upper atmpospherer-no debris on earth

(hopefully!)

• And some exotic ideas...

Tractor Beam?

Lasers?

• Can we develop a simple, low cost deorbiting system for

satellites or upper stages to stop the problem getting worse?

• Can we clean up space from space junk?

Debris Removal/Mitigation

• No single or ‘silver bullet solution’ solution

• Where possible, use propulsion (e.g. electric propulsion)

• Mass penalty, assumes satellite in operation/active

• Surrey Deorbiting strategy/steps:

1. Drag augmentation devices/demonstrate feasibility

• Cubesail, DEORBITSAIL, Inflatesail

2. Commercialise for spacecraft as a ‘bolt on’ system

• Gossamer Deorbiter (ESA funded)

3. Find a way to attach deorbit systems to uncooperative

debris/targets (long term research)-RemoveDEBRIS mission

CubeSail Mission Objectives

• Demonstrate deployment of 25 m2 solar sail (5m x 5m) • Test satellite deorbiting • Use drag for deorbiting

• Test Solar Sail propulsion • Change in inclination ≈ 2-3°/year in 700 km orbit

• Implement a 3-axis active ADCS to align sail to orbit plane for minimum drag in LEO

• Measure solar force over a minimum 1 year period • Funded by EADS Astrium • Launch date: 2012/early 2013 • Complete spacecraft specifications: 3U Cubesat, 3 kg, 10 x 10 x

30 cm

CubeSail: ‘Solar Sail’

• Use of photons from the Sun (free!)

• Build up of a significant velocity (continuous reflection of photons) in time

• ‘Propellant-less’ propulsion system

CubeSail mission concept

Solar propulsion demonstration

Cubesail: ‘Drag Mode’

• In Drag-Sail mode the deployed membrane will be used to increase the

area of the spacecraft

• It will interact with the atmospheric particles, causing an increase in drag

and result in a more rapid deorbiting.

Cubesail: The Technology

Early Deployment

System Concept (2009)

• Back-to-back tape measures for booms

• 4x booms coiled around a centre spindle

• Sail membrane attached to boom ends and lifted above the coiling plane

• Simple, robust, ultra-light (< 2 kg)

Cubesail Deployment System

Satellite Bus-Cubesat 3U

1.7x1.7m 4-Quadrant Sail prototype

4 x1.3m 0.3mm Co-coiled Booms (two

tape-springs held front-to-front)

In-house heat-treatment of Becu flat

strips to provide curvature

Coated with aluminized Kapton tube

(sheath) for thermal control

Sail Deployment Subsystem

Sail membrane

Membrane

spindle

25mm boom

Spindle release

Batteries

Control

electronics

CubeSat base

Central Shaft

• 4 Booms co-coiled around a single spindle • Sail folded in a volume below the coiled booms • Boom properties dictate the rest of the design

Generic Sail Deployment (2009-current)

(a) TRAC mast (b) Lenticular boom

(c) STEM with overlap

(d) Tape spring

(e) ()-shaped boom

(f) STEM without overlap

Metallic booms • 2 Copper-beryllium half-shells with

Kapton sleeve make a lenticular shape • Booms extend linearly • Deployment mechanism has to

constrain booms inside mechanism

BRC (bi-stable reeled composite) booms

• Single half-shell is made to be bi-stable • Carbon-fibre Reinforced Plastic (CFRP)

booms • Deployment energy is present only at

transform between two states • Booms unfurl from the spindle

SSC working on 2 different designs

Sail deployment

• 2 Copper-beryllium tape springs in a Kapton sleeve

Metal booms

Cubesail Deployed

1.7 x 1.7 m sail

Uncontrolled Deployment

(b)

(e)

Deployment on the Airbearing

Improved 1.7 x 1.7 m Sail

Sail Deployment

• Bi-stable reeled composites (BRC): stable in coiled and uncoiled form

• Manufacturing: • New manufacturing technique for producing bistable CFRP

deployable booms with a thermosetting matrix has been developed • Dry carbon fibre in a biaxial braid sleeve and unidirectional form • Impregnation with a space qualified epoxy resin film

BRC booms

Sail deployment

(a) Folding pattern 1

(b) Folding pattern 2

(c) Folding pattern 3

(d) Spiral folding pattern for single square sail

Sail folding

(a) Folding pattern 1 stored and deployed

(b) Folding pattern 3 stored and deployed

Cubesail Sail Deployment System

• Currently building 5 x 5 m BeCu and CFRP systems

• Similar deployment mechanism

• Booms are complete/ready for testing

• Currently testing 1 x 1m sail systems (BeCu and CFRP) in

vacuum, thermal facilities and functional tests

• Testing of 5 x 5m systems in August 2012

• Other subsystems have been procured

• Will select with Astrium which technology to fly in Cubesail

• Deciding on launch options - piggyback payload for Q1 2013

Status Update

Sail Deployment Subsystem

In house manufacturing facility of metal (CuBe) tape-springs

Various forming tube sizes for different boom curvatures

CFRP Booms

CFRP 3.6m Booms

• Different ways of using solar force for attitude control: • Change sail orientation: control vanes, tilt-able structure • Change sail reflectivity: electro-chromatic panels (like IKAROS) • Change centre-of-mass (CM) to centre-of-pressure (CP) vector

• Focussing on the latter method: • The satellite will rotate around its centre of mass (CM). • The centre of pressure (CP) is the middle of the effective sail area. • If the CP/CM vector is not aligned with the force vector, a torque is generated

Attitude control How can we control large structures?

Centre of

mass

Centre of

pressure

SRP

• Sensors: • Sun and Nadir optical sensors (camera’s) – determine sun and nadir

vector in spacecraft body coordinates • 3-Axis magnetometer • Y-axis aligned MEMS gyroscope

• Actuators: • Magnetic torquer rods • Novel 2-axis translation stage – uses controlled CP/CM offset to

generate torque

Sail attitude control

ADCS Avionics (flight hardware)

Translation Unit • 2-Axis translation stage between satellite bus and sail • Creates a controllable offset between the centre-of-mass and centre-of-pressure • Stepper motor drives rack-and-pinion system to move stage along linear slides

Translation Stage

Simulation: Detumble

SS Cubesat - Detumble(MT on-time = 7897.8 sec)

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Simulation: 3-Axis control (1)

SS Cubesat - Magnetic & Sail 3-Axis control(MT on-time = 290.7 sec)

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SS Cubesat - Magnetic & Sail 3-Axis control(MT on-time = 290.7 sec)

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• 3U CubeSat form factor • Custom structure with deployable solar panels

Cubesat Structure manufacture

• Progress • Mechanical design completed • EM structure manufacture complete and assembled (excluding bottom

plate) • Passed fit-check with electronics modules

Structure manufacture

• Demonstrate deorbiting • Demonstrate deployment of 25 m2 solar sail • Implement a 3-axis active ADCS to align sail to orbit plane =>

minimum drag in LEO • Measure solar force over a minimum 1 year period • Based on COTS, 3U Cubesat • Funded by the European Commission (2011) • Budget of 2.8 million Euros including launch • Framework 7 program –FP7 • Difference to CubeSAIL:

• Carbon Fiber booms/deployment system designed by DLR

• Fit in a 3U Cubesat nanosatellite, launch in 2014 • www.DEORBITSAIL.com

The Team

Name Country Main role in the project

1 Surrey Space

Centre UK

Coordinator; Sail Mission requirements; sail technology

survey; solar sail mechanism/deployment; flight model

functional testing; management

2 Caltech USA Solar Sail modelling and simulation; finite element analysis

3 ASTRIUM UK Solar Sail materials, Solar Sail testing

4 DLR Germany Development, manufacturing and test of deployable

gossamer booms

5 Stellenbosch

University South Africa Spacecraft attitude determination and control

6 University of

Patras Greece Cubesat (satellite) CF structure, thermal analysis

7 Athena Greece Satellite electronics,testing, dissemination and

communications

8 METU Turkey Sail boom controls/damping

9 SSTL UK Flight operations, flight data analysis, ground station support

10 ISIS The

Netherlands

Satellite subsystems (power, RF), integration, flight campaign

and launch vehicle integrator

Project objectives

• Design, manufacture, and launch of a satellite providing:

• Research in the field of deorbiting

• Validated deorbiter design

• Effective sail propulsion technology

Sail Mechanism-DLR

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IM-Carbon 0/90/0

HT-Carbon 0/90/0

HT-Carbon 0/±45

Boom structural analysis results

Boom cross-section (DLR)

Thermal balance of spacecraft

• Analysed by SSC in ESATAN-TMS

• Sail thermal effects are tolerable

• More detail possible as bus layout and power consumption are

developed

D1.5 – Thermal balance of spacecraft

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ESA Gossamer Deorbiter

• Gossamer Deployer: deorbiting device for future

space equipment

• Deployable sail for end-of-life manoeuvres using

aerodynamic drag and solar sailing

• Funded by ESA

Mission Concept

ESA Gossamer Deorbiter

• Telescopic extension based on P-POD deployer for CubeSats

• Extends sail past satellite appendages, allows for universal

mounting

Deployment

ESA Gossamer Deorbiter

ESA Gossamer Deorbiter Telescopic deployment

CFRP vs. metal booms (25 sqm sail)

CFRP CuBe DLR

Mass 19 g/m 50 g/m 25 g/m

Mass for 5-by-5-m

sail with four booms

260 g 700 g 360 g

Coiled height 45 mm 25 mm 65 mm

Torsional stiffness

(JG = τL/φ)

7-9 mN·m2/radian 32-37

mN·m2/radian

TBC

Deployer mass 408 g 365 g < 500 g

Boom system mass 668 g 1065ng 960 g

With 10 μm Kapton

sail (355 g)

1023 g 1420 g 1315 g

Collision Probability with Debris

Collision Analysis For Iridium/Orbcomm

Iridium Orbcomm Initial altitude (km) 781 725 EOL Bus mass (kg) 526 100 Bus area (m2) 12 1 Drag area (to de-orbit within 25 years) (m2)

45 12

Time to de-orbit unassisted (years)

100 110

Catastrophic collision probability Probability of impact during

non-assisted de-orbiting 15.6% 1.4 %

Probability of impact

during drag assisted de-orbiting

2.4% 0.22 %

Non catastrophic collision probability Probability of debris impact

with sail membrane 17.8% 1.45 %

Probability of sail impact

with functional satellite 0.05% 0.004 %

InflateSAIL: A Scalable Deorbiter

DEPLOYTECH Project

• The objective of DEPLOYTECH is to develop 3 specific,

useful, robust and innovative large space deployable

technologies:

• 3.3 m diameter inflatable sail – Inflatesail – Surrey/Astrium

• 1m x 5m deployable solar array – RolaTube/Surrey

• 14m solar sail booms - DLR

• The aim is to develop these technologies from a current TRL

of 2-3 to 6-8 within the 3 years of the proposed

DEPLOYTECH project.

• FP7 Funded, 2.8 million Euros, kick off in March 2012

The Team

* NASA Marshall Space Flight Center participating as a cooperating partner

Inflatable sail QB50 payload - Concept

• Circular sail supported by inflatable structure • Sail area of ~10m2 (3.3m diameter)

• Inflatable torus frame stretches sail to full size • Suspended from satellite bus by 3 inflatable booms • Stowed volume of 10 x 10 x 20 cm • Inflation by Cold Gas Generator (CGG) • Structure made from self-rigidizable material • Similar concept to L’Garde Inflatable Antenna

Experiment

• Scalable, Lowest mass solution • EU funded, flight testing in 2015 on QB50 mission • www.DEPLOYTECH.eu

InflateSAIL

3.3 m diameter

3 x 2 m booms

for deployment

3U Cubesat

Deployable arrays

Mylar or CP-1

InflateSAIL Inflation System – Cold Gas Generator

• Nitrogen CGG – manufactured by CGG Technologies B.V. and TNO

• Successfully tested as a thruster on ESA’s PROBA-2 satellite

• 15.3g of nitrogen produces 13.3 litres of gas

• Cylindrical shape • diameter: 35mm • Length: 65mm

• Includes actuation and filter • Electrical ignition: 10W power

required for 10s

RemoveDEBRIS: A Low Cost, Active Debris

Removal Demonstration Mission Concept

The Next Step/Future: RemoveDEBRIS

• Propose a low cost Active Debris Removal Mission with small

satellites in LEO (400-500 km):

• Active Microsatellite with a deployable net/tether, capable

ADCS for detumbling, propulsion and a drag-sail

(Cubesail/DEORBITSAIL)

• Passive satellite: a 3U Cubesat with video/imagers, intersatellite

link

• Microsatellite captures a 3U cubesat, sail is deployed and then

deorbited in a combined manner in the earth’s atmosphere

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Ground test: Dec. 2009, Rocket test

planned summer 2012

Outreach-Public Interest

Conclusions

• Space Debris, an important problem, need to act now!

• An interesting, complex, interdisciplinary technical problem with some

commercial potential, strong academic/engineering outputs

• UN 25 year deorbiting recommendation, becoming the law..

• Surrey approach:

• Demonstrate drag augmentation based deorbiting using

• Cubesail, 5 x 5m, 2012/2013

• DEORBITSAIL, 5 x 5m, 2014-CFRP booms

• Inflatesail, scalable inflatable device, 2015

• Commercial deorbit ‘bolt-on’ system, Gossamer Sail, ESA funded, 2014

• Active debris removal demonstration mission using nanosatellites

Acknowledgements

• The Surrey Team:

• Johnny Fernandez, Lourens Visagie, Nasir Adeli, Theo

Theodorou, M. Muhadri, Dr. Olive Stohlman, Dr George

Prassinos

• DEORBITSAIL, DEPLOYTECH project partners

• European Commission, Framework 7 Program

• EADS Astrium