Changing the economics of space

1

Space Technology Needs:Satellite Systems – Technology Trends

April 2010

Dr Kathryn Graham

Mission Concepts Team Leader

Surrey Satellite Technology Ltd

April 2010 – SSTL, UK

22

Contents

• Small satellites and the SSTL perspective

– What is a small satellite?

• Technology Trends – small satellites

• Example small satellite missions

• Where next

– Future trends

• Enhanced capability

• Constellations

• Nano satellites

• Responsive space

• Conclusions

3

What is a small satellite

• Low mission cost– NTE budgets: What can be achieved given a budget of ‘X’– “low cost” depends on context, e.g.

• <US100k to $1m in educational missions• <US$10m for private missions• <US$50m for small national missions• <US$200m in Space Agencies

• Short schedules– From 12 months up to 36 months

• “Innovative” or different approach from the norm

• Effective Design and Implementation Philosophy– Engineering approach

• E.g. COTS– Management principles

• E.g. What is important for this mission?– Organisational structure

• E.g. no major sub-contractors– Simple operations concept

4

What are small satellites?

• A widely accepted classification of satellites is as follows, though there are variations amongst different organisations:

Group name Wet Mass

• Large satellite >1000kg

• Medium sized satellite 500-1000kg

• Mini satellite 100-500kg

• Micro satellite 10-100kg

• Nano satellite 1-10kg

• Pico satellite 0.1-1kg

• Femto satellite <100g

• Generally all spacecraft under 500kg are referred to as small satellites

• Note that in the GEO satellite communications sector, the term “small satellite” is used differently, for satellites with power less than approximately 2.5kW.

Small Satellites

5

Why use small satellites

• Reducing the cost of entry into space– Achieving more missions within fixed budgets– Ownership for all - a mission focused and dedicated to the owner’s specific task,

rather than sharing a government mission that has aggregated demand

• Reducing the time to get into orbit– More frequent mission opportunities– Responding rapidly from initial concept to orbital operation

• Making constellations and formation flying financially viable– Higher spatial coverage– Higher temporal resolution– Larger apertures

• Making new space opportunities financially viable– Scientific investigations– Commercial ventures– Public good

Currently operational satellites launched in the last 10

years

0

10

20

30

40

50

60

70

80

90

100

1999 2001 2003 2005 2007 2009

Number of launches

all

small

large

6

Example small satellites

• Small Satellites used for a wide range of applications

– Including

• Science

• Earth Observation

• Communications

• Education

• Technology demonstration

• Security

0

2

4

6

8

10

12

14

16

199019

9119

9219

9319

9419

9519

9619

9719

9819

9920

0020

0120

0220

0320

0420

0520

0620

0720

0820

09

EO missions

no of science missions

Smallsat application evolution

<500kg

0%

20%

40%

60%

80%

100%

197019

7219

7419

7619

7819

8019

8219

8419

8619

8819

9019

9219

9419

9619

9820

0020

0220

0420

06

Communications

EO

Education

Science

Tech demo

Security

7

Example smallsat EO missions

• Smallsat capabilities now becoming compelling for many users with scientific or operational needs.

• DMC Daily global multispectral wide swath imaging

• Beijing-1 Operational high resolution imaging

• TOPSAT Tactical surveillance

• BIRD Hot spot detection and monitoring

• PROBA Hyperspectral imaging

• RapidEye Constellation of EO imaging satellites

• NigeriaSat 2 Highly agile optical imagingEO Smallsats <500kg

0

1

2

3

4

5

6

7

199019

9119

9219

9319

9419

9519

9619

9719

9819

9920

0020

0120

0220

0320

0420

0520

06

8

Disaster Monitoring Constellation

• DMC features– International cooperation with

individual satellite ownership– Ultra-wide swath, 32m

multispectral, 4m pan (Beijing-1)– Latest generation 22m

multispectral data– Daily revisit

• Six operational spacecraft– AlSAT-1 (2001), UK-DMC,

NigeriaSat-1, Beijing-1 (2005)– Deimos1 and UK DMC 2

launched 2009– and NigeriSat-2 due 2010

• Global daily imaging capability – stimulates new EO applications

and services

First internationally coordinated constellation

ALSAT-1

UK-DMC1 and 2

NigeriaSat-1

Beijing-1

Deimos-DMC

N2(2010)

9

Beijing-1 project

• Mission– Systematic mapping of China over a 5 year period– Participate in Disaster Monitoring Constellation (DMC)

• Platform– SSTL 150, 166kg mass, 50 W OAP– Stable and Flexible Attitude Control

for Off-Pointing Imaging– Off-nadir pointing

• ±30º Roll– Control 0.1 º (3-σ), stability 2.5mdeg/s– GPS navigation– Xenon electro-thermal propulsion, 17m/s– S band TM/TC

• High resolution payload– 4-metre GSD pan (SIRA Ltd)

– 24km swath width 3,000km swath length

– X band downlink (40Mbps)– 3 Gbytes solid-state storage– 240 Gbytes hard disk storage system

• DMC payload– 32-metre GSD multi-spectral (3-bands)– >600km swath width– 8Mbps S-band downlink– 1.5Gbytes Solid State Storage

Launch - Oct05

10

TopSat Mission

• Spacecraft– 112 kg Enhanced microsatellite, 686km sun sync orbit

– 2.8 m resolution panchromatic imaging

– 5.6 m resolution, 3-band (R,G,B) multi-spectral imaging

– 5 images per orbit

– Nominal 1 year lifetime – still operating

• Agile spacecraft – to provide Motion-compensated Time Delay Integration

• Ground segment– RAPID Mobile Ground Station

• Ground station rack and data processing

• X-band 2.7m antenna receive at 11 Mbps

– West Freugh fixed system

• Payload data return at X band, 13m antenna

– SSTL ground station

• S band TM/TC

15km

Pushbroom with TDI x8 (~16 secs)

15km

Pushbroom with TDI x1 (~2 secs)

RutherfordAppletonLaboratory

11

BIRD

• Earth science: hotspot detection

– Hotspot detection

– Vegetation analysis

• Commissioned and primed by German Space Agency DLR

– Launched 2001, operated until 2005

– 30kg payload on 92kg platform

• JPEG compressor

• 1Gbit data recorder

• 2Mbps S-band

• 2 star cameras

– Platform

• Deployed solar panels, 120W

• NiH battery

• 4 x PowerPC MPC623

• 3-axis control,

– Control 0.1deg

– Knowledge 0.003deg False color image of Etna eruption, and measured lava temperature

1219 km

Beginimaging

Endimaging

Line of sightof imager

Image 2Image 4Image 5 Image 1Image 3

1

23

45678

9

10

PROBA

• Technology demonstration and Earth Science

– Hyperspectral imaging (17m GSD, 19 bands)

• Highest resolution H/S achieved in orbit

– Panchromatic imaging (5m GSD)

• Primed by Verhaert for European Space Agency

– Launched 2001, still operational

• 94kg spacecraft with 25kg instrument and 30kg technology payload

– 17m GSD hyperspectral imager

• Platform

– Agile 3-axis control

• 150arcsec absolute accuracy, 10arcsec of relative pointing over 10s, 1deg/s slewing, 2 headed star tracker

– S-band 1Mbps downlink

– 100 MIPS computer

– 1.2Gbit data storage

– 120W peak, LiIon Batteries battery

Hyperspectral cube

CHRIS Hyperspectral Imager

PROBA Spacecraft

Typical h/s image sequence

13

RapidEye constellation

• Mission prime MDA, platform provider SSTL, payload Jena

• 5 Spacecraft, single Dnepr launch• World’s first commercial remote sensing

system• 80km swath at 6m resolution in 5 visible

/ NIR bands• Ability to image any point on Earth

within 1 day• Capacity to image the world’s major

agricultural areas every two weeks• 1 million square km of imagery per

spacecraft, per day

14

SSTL 300 Optical Imager

• 3 Imagers– Panchromatic 1.2 m resolution; 15 km swath

– 4 Band Multi-Spectral 5.6 m resolution; 15 km swath

– 4 Band Multi-Spectral 15 m resolution; ~200 km swath

• Multiple Operational Modes– Spot, Strip, Fast-response, Area, Stereo

– Possible additional modes include: Low-elevation,

Line of communication, Super-resolution, Change Detection,

Joystick Control

• High accuracy pointing (better than 15 m geolocation)

• 2 Day Revisit to Anywhere on Earth

• Fast slewing in roll and pitch

• 7 Year Life

• 150-400 images per day

• Mass - 300 kg

15

SSTL 300 Very High Agility

• Small satellites can achieve much faster attitude-change manoeuvres than larger platforms

• SSTL 300 can achieve

– Roll manoeuvre of 35 degrees in 20 seconds

– Ability to slew to any attitude within a 45 degree cone from nadir

• Accurate pointing maintained during slew through precisely calibrated inertia tensor

• Opportunities for data downlink between imaging activities

• Provides a range of image modes

12

16

Small Space Science missions

• Smallsat missions are widely used in space and Earth science

– Generally funded by smaller space agencies or government research councils

– 2-6 missions/year

• Applications

– Optical and Gamma ray Astronomy

– Space environment

– Solar science

– Upper atmosphere science

– Magnetospheric science

– Many more… Scientific Smallsats <500kg

0

2

4

6

8

10

12

199019

9119

9219

9319

9419

9519

9619

9719

9819

9920

0020

0120

0220

0320

0420

0520

06

17

Small Space Science missions• Examples

– ORSTED (TERMA for Danish Space Agency)

• Magnetospheric science

• 62kg, 350x450x680mm

– DEMETER (French Space Agency)

• Earthquake science

• 130kg, 600x600x900mm

• 14meuro (US$17m) program

– SCISAT (Magellan Aerospace for CSA)

• Atmospheric science

• 150kg, 500mm x 1500mm Ø

• US$40m programme

– MOST mission (Dynacon for CSA)

• Space Astronomy (stellar invariability)

• US$6m spacecraft (CAN$10m)

• 51kg, 630x580x250mm

• Inertial pointing to arcsecond precision

– HETE-II Mission (AeroAstro for NASA)

• Space Astronomy (Gamma Ray Burst)

• 30 month contract to launch readiness

• US$8.5m platform, US$14m launch

• 120kg, 890mm x 660mm Ø

• Inertial pointing, rapid data alertsHETE-II (2000)

MOST (2003)SCISAT (2003)

DEMETER (2004)

ORSTED (1999)

18

Trends in small satellite launches

• Mini satellites (100-500 kg) tend to average 14 launches per year

• Micro satellites (10-100 kg) average ~17 launches per year

• Nano satellites (<10 kg), much fewer launches, but the trend is increasing and is expected to increase further

Small satellite launches

0

10

20

30

40

50

60

70

80

197119

7319

7519

7719

7919

8119

8319

8519

8719

8919

9119

9319

9519

9719

9920

0120

0320

0520

0720

09

Number

mini

micro

nano

19

Performance Trends

• Orbit average power generated is typically less than 1W for each spacecraft kg.

– Inertial pointing missions or those with tracking panels can perform better

• Typical payload mass fractions are ~30%

Small Satellite mass vs payload mass

1

10

100

1000

10 100 1000

Total Mass (kg)

Payload mass (kg)

Interplanetary

Small Satellite mass vs generated power

1

10

100

1000

10 100 1000

Mass (kg)

Orbit Average Power (W

)

LEO comms

20

SSTL EO satellite trends

• General trend for improving resolution

• Area coverage (for any given resolution) improving.

• Number of pixels taken per day is improving

0

200

400

600

800

1000

1200

1988 1993 1998 2003 2008 2013

GSD (m)

0

2000000

4000000

6000000

8000000

10000000

12000000

Area Coverage (km2)

GSD

Area Coverage

0

200

400

600

800

1000

1200

1988 1993 1998 2003 2008 2013

GSD (m)

0

5000

10000

15000

20000

25000

Million pixels per day

GSD

million pixels per day

21

SSTL EO satellite trends

• Payload data downlink rates and data storage capabilities improving.

• If examine SSTL satellites over the last 25 years, its clear improvements are broadly following MooresLaw

– Order of magnitude improvement with every decade

– Future concepts

show this trend continuing

Surrey missions - payload data rate

0.0001

0.001

0.01

0.1

1

10

100

January-80

December-84

January-90

January-95

January-00

January-05

Launch date

Data rate (Mbps)

Surrey missions - Data Storage

1

10

100

1000

10000

100000

1000000

January-80

December-84

January-90

January-95

January-00

January-05

Launch date

Data Storage (Mbyte)

0

50

100

150

200

250

1987 1992 1997 2002 2007 2012

Payload data downlink rate (Mbps)

0

5

10

15

20

25

30

35

On-board Data Storage (GB)

downlink rate

downlink storage

22

– Power:

• Solar Array Efficiencies Have Increased from 18% to 28%

• DC/DC Converter Efficiencies Have Increased from 86% to 93%

• FET Switches Have Nearly Zero ON Resistance

• Li-Ion Batteries Greatly Improve Specific Energy Storage Values

– RF Systems:

• Greatly Enhanced and FASTER Design and Modelling Tools

• SSPA DC-to-RF Efficiencies Have Improved from 30+% to 50+%

• FEC Coding Has Reduced Eb/No Requirements by more than 2 dB*

• Evolved from VHF to S and now X band for payload data downlinks

93%86%DC/DC converter efficiency

28%18%Solar cells

20071992Example in improvement

Improvements in small satellite technology since the mid 90’s

* Compared to Best Coding Performance Known in 1990

23

• Attitude Control and Computing Technologies

– On-Board Computation and Signal Processing Have Improved by 2 Orders of Magnitude (Tracking Moore’s Law)

– Data Storage Capacity Has Improved by 3 Orders of Magnitude (better than Moore’s Law)

– MIPS/Watt are Higher by 2 Orders of Magnitude (Moore’s Law)

– Real “Small Satellite” Reaction Wheels Exist

– Small Satellite High Accuracy Sensors Are in Common Use

• Propulsion

– In the early 90’s it was uncommon for small satellites to have propulsion.

– As miniaturised propulsion components become available propulsion systems have developed and greater Delta V capabilities have evolved from 11m/s on the early DMCs to 35m/s on SSTL 150s

– With de-orbit regulations propulsion and/or use of de-orbit technologies will improve and be developed in the future

Improvements in small satellite technology since the mid 90’s

24

• Structures and Mechanical Engineering Technologies

– Mechanical Design and Modelling Tools Have Advanced by at Least One Order of Magnitude in Capability and Speed

– Composite Structures Are Now Applicable for Small Satellites

– Small Satellite Missions Now Embrace Appropriate Deployable Technologies (e.g. deployable solar panels)

ADCSData handlingStructures

Smaller &Cheaper

Improvements in small satellite technology since the mid 90’s

25

Where next?

• Greater capabilities– With continuing improvement in small satellite capabilities opens up

opportunities for more enhanced missions, e.g,

– higher resolution visible imagery, aiming for sub metre

– Use of different sensors, e.g. hyperspectral, IR, SAR, altimeters

– Gap filling missions, e.g.

• S5P

– Science missions, e.g.

• Climate change initiatives, several agencies/countries

looking at potential for this– E.g. Carbonsat (DLR), miniCarb (CNES)

• Exploration e.g. Moonlite

• Low cost, but effective capabilities opens up potential for more satellite constellations, e.g.– EO observation constellations to provide improved

spatial and temporal sampling

– Altimetry constellations

26

Where next?

• Nano satellites

– Already a trend for more nano satellites – both for educational and operational missions

– As COTS technologies improve this trend is expected to continue

– Use of small/ nano satellites in formation to provide capabilties traditionally provided by larger satellites, e.g.

• FIRST radio interferometry (Psi Tran, SEP, IRF, NPL, ESA),

• AAReST (SSC, Caltech, NASA/JPL)

– Reconfigurable space telescope concept

• Cubesail (SSC, Astrium)

– A deployable sail from a nano-satellite

• Responsive space

– Small satellites are generally built and launched in much shorter timeframes.

– Growing interest in small satellites being used for responsive space needs, particularly for security applications

27

Where Next?

• Technology Demonstration

– The use of COTS relies on components proving to be flight worthy.

– Small satellites provide an ideal testbed for providing flight opportunities for new technologies

– TechDemo satellite

• Primary aim is to flight qualify new UK space equipment – both satellite subsystems and payloads.

• SSTL Space segment and mission prime, Vega is Ground Segment lead

• Platform is the SSTL 150 product.

• 10 payloads have been down-selected for inclusion at this stage, based on

– Business potential

– Suitability of the technology to

the heritage SSTL satellite facility

– Payload development, risk and

programmatic factors

• Payload providers include:

– Selex Galileo, SSTL, RAL/Oxford Uni,

QinetiQ, Aerosekur, ComDev, MSSL,

Surrey Space Centre, Langton Star

Centre

28

Conclusions

• Small satellites are playing an increasing role and their performance and capabilities are expanding

• As this trend continues this opens up a new range of capabilities for the future.

• Thank you for your time.