cubesat technology and systems dr. siegfried...

THE AEROSPACE CORPORATION CORPORATE OVERVIEW 2013

CubeSat Technology and

Systems

Dr. Siegfried Janson

Presented to the USGIF Small Satellite

Working Group , 27 May 2015

THE AEROSPACE CORPORATION Cubesat Technology 5/27/15

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About Aerospace Corp

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scientists, and

managers

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Trustees

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corporation

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employees

The Aerospace Corporation – an FFRDC



Aerospace Benefits

• Evaluates complex technologies – Supports governments’ technical depth

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– Serve on any source selection

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El Segundo, CA

Colorado Springs, CO Chantilly, VA

Onizuka Air Force Base, CA

Vandenberg Air Force Base, CA

Pasadena, CA

Kirtland Air Force Base, NM

Albuquerque, NM

Peterson Air Force Base, CO

Denver, CO

Offutt Air Force Base, NE Wright-Patterson

Air Force Base, OH

Huntsville, AL

Houston, TX San Antonio, TX

Patrick Air Force Base, FL

Cape Canaveral Air Force Station, FL

Columbia, MD

Washington D.C. (area)

Rosslyn, VA

Falls Church, VA

Corporate Offices

Decatur, AL San Diego, CA



Customers

59% 31%

10%

FTE Deliveries

FY12 Revenue and Deliveries

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Civil, Commercial & Int’l Market



Aerospace Principal Functions

• Architecture planning

& development

• Assess design &

performance risk

• System acquisition

support

• Flight Certification &

lifecycle

implementation



Cubesat Technology –

Background and context

Cubesat Technology

9

Nanosatellite Launch History; 5 years ago

Nanosatellite launch rates were rising rapidly above a legacy 3 per year rate. A disruptive technology called CubeSats had started.

10

• 1998 AFOSR/DARPA/AFRL Workshop

on Micro/Nanotech for Micro/Nanosats

- 1998 DARPA seed money for PICOSATs

- DARPA/AFOSR funding for Stanford OPAL microsat

• OPAL ejects six Picosats in 2000

- Stensat and Jak (4” x 3” x 1”)

- Thelma and Louise (8” x 3” x 1”)

- PicoSat 1.0A & -B (4” x 3” x 1”)

CubeSat Genesis: Containerized PicoSats

Stanford OPAL Spacecraft

Aerospace

PicoSats (2)

DARPA funded Stanford to fly the “Orbiting Picosatellite Automated Launcher” in 1998.

(OPAL). This microsatellite ejected six picosatellites; 2 were from Aerospace.

11

Scaling Up the Picosatellite Ejector: CubeSats

• 4 x 4 x 10-inch payload

• 3.5-kg capacity

Aerospace 4410 Launcher

Aerospace 5510 Launcher

• 5 x 5 x 10-inch

payload

• 7-kg capacity

• Heaters

P-POD

CubeSat

Launcher

• 5-kg capacity

• 10 x 10 x 30 cm payload

• Standardized:

- Shape

- Operation

- Electrical

- Containment

Stanford Picosatellite Launcher

• 1 x 3 x 8-inch payload

• 0.5-kg capacity

THE AEROSPACE C O R P O R A T I O N



The Winner: CubeSats

The CubeSat standard evolved from the OPAL launcher and was developed by Stanford

and Cal Poly San Luis Obispo for expendable boosters. The Aerospace launchers

were developed for U.S. Space shuttle launches.

12

AeroCube-3 CP-6

HawkSat-1

P-POD

• Containerized delivery of satellites - Orbital deployer provides physical

containment of secondary satellites

- Less risk for primary satellite

- Container gets flight-qualified for a

launch vehicle, not individual spacecraft

• Improved access to space - Wide variety of international launch

options every year A-POD for Space Shuttle

Standard P-POD with three CubeSats

The CubeSat standard allowed ejectors to be flight-qualified for any launch vehicle only

once as long as the CubeSats within met certain specifications. Major cost savings.

CubeSats:

13

Date Vehicle Country MicroSats NanoSats PicoSats 1U 1.5U 2U 3U PQ Total

Jan. 30, 2013 KSLV-1 South Korea 1 1

Feb. 25, 2013 PSLV-C20 India 1 2 1 1 5

April 19, 2013 Soyuz-2-1a Russia 1 4 1 6

April 21, 2013 Antares United States 3 1 4

April 26, 2013 CZ-2D-2 China 1 1 1 3

May 7, 2013 Vega European Union 1 1

Aug. 3, 2013 H-2B-304 Japan 3 1 4

Sept. 29, 2013 Falcon-9 United States 2 3 5

Nov. 20, 2013 Minotaur-1 United States 12 8 8 28

Nov. 21, 2013 Dnepr Russia 4 2 1 10 2 7 4 30

Dec. 5, 2013 Atlas-V United States 3 4 5 12

Dec. 15, 2013 Soyuz 2.1v Russia 1 1

TOTALS: 10 7 1 38 12 3 25 4 100

2013 Small Satellite Launches CubeSats

PQ = PocketQube; a new sub-CubeSat variant

There were twelve launches of micro- and smaller satellites in 2013; over 80% were

CubeSats. Nine launches from a variety of countries supported CubeSats.

14

Date Vehicle Country Micro Nano Pico 0.5U 1U 1.5U 2U 3U 6U PQ Total

Jan. 9, 2014 Antares 120 United States 4 1 28 33

Feb. 27, 2014 H-2A Japan 2 2 4 8

April 18, 2014 Falcon-9 United States 1 1 3 5

May 24, 2014 H-2A Japan 3 1 4

June 19, 2014 Dnepr-1 Russia 8 2 2 4 4 14 2 36

July 8, 2014 Soyuz-2-1B Russia 2 1 1 4

July 13, 2014 Antares 120 United States 1 31 32

Aug. 4, 2014 CZ-2B China 1 1

Aug. 19, 2014 CZ-4B China 1 1

Sept. 8, 2014 CZ-4B China 1 1

Sept. 21, 2014 Falcon-9 United States 1 1

Oct. 28, 2014 Antares 130 United States 1 28 29

Nov. 6, 2014 Dnepr-1 Russia 4 4

Dec. 3, 2014 H-2A Japan 2 2 4 8

TOTALS: 25 8 4 2 14 0 7 105 2 0 167

2014 Small Satellite Launches New New

There were fourteen launches of micro- and smaller satellites in 2014; 78% were

CubeSats. Seven launches from a variety of countries supported CubeSats.

Red: Launch vehicle failure

More small satellites made it into orbit in 2014 than in any previous year

15

Twenty Years of Small Satellite Launches

The sudden increase in small satellite launch rates is primarily due to CubeSats.

16

Cost and Schedule

• Launch cost for a 10-cm “1U” CubeSat is $50,000 to $120,000 - Multiply this base cost by the “U” size of your spacecraft

- Cheapest way to get into space, if you’re paying for the flight

• NASA offers free flights through the CubeSat Launch Initiative - “To participate, investigations should be consistent with NASA's Strategic

Plan and the Education Strategic Coordination Framework.”

- “The research should address aspects of science, exploration, technology

development, education or operations.”

- High schools and universities have gotten free flights

- URL: http://www.nasa.gov/directorates/heo/home/CubeSats_initiative.html

• Multiple (on the order of 10) flight opportunities each year - U.S., Russian, Chinese, Indian, Japanese, and European launchers

- Mostly flights to Low Earth Orbit

- Geosynchronous and interplanetary trajectories are becoming available

CubeSat flights are relatively cheap and happen often. New missions using 1,2, or 3

CubeSats with significant technology development can cost $3 to $14 million (NASA

Edison program).

http://www.nasa.gov/directorates/heo/home/CubeSats_initiative.html

http://www.nasa.gov/directorates/heo/home/CubeSats_initiative.html

17

The Real Revolution

• Traditional “large” spacecraft took 5 to 10 years to build - Technology freeze dates could be 7 years before launch

- The flight computer could be two generations out-of-date at launch time

- Significant amounts of ground testing, plus simulations, required to achieve

high reliability

• CubeSats can be designed, built, tested, and flown within 1 year - Get real flight data within a year to improve device design

- The evolutionary cycle for space hardware, that can fit on a CubeSat, has

been reduced by a factor of roughly 7.

- Get two or three successive flight validations before committing to a new

technology; “Fly as you Fly”

- Take advantage of the latest commercially-available technologies

The “Fly as You Fly” approach leverages the low cost and frequent flight opportunities

for CubeSat technology demonstrations.

18

What Can I Fly?

• Software - Software can consume more than 50% of the development cost for a new spacecraft,

even for CubeSats!

- Not all data input combinations, especially with radiation-induced errors, can be

tested on the ground.

• Sensors - Attitude sensors (sun, Earth, and star sensors, rate gyros, accelerometers)

- Proximity sensors (laser and RF rangefinders, cameras, etc.)

- Payload sensors (focal planes, plasma sensors, antennas, etc.)

• Electronics - Microprocessors, memory, signal processors, field-programmable gate arrays, etc. in

a relevant, or higher, radiation environment

- Communications systems; RF and optical

• Actuators - Reaction wheels, magnetic torque rods, deployment mechanisms, filter wheels, etc.

- Thrusters and solar sails

- Cryo coolers, thermal control systems, etc.

A high radiation environment, like geotransfer orbit, can be used to simulate a more

moderate environment like geostationary orbit at an accelerated rate.

19

What Can I Fly? (Continued)

• Materials and Surface Treatments - Solar UV exposure plus atomic oxygen; monitor degradation and erosion

• Space biology experiments - Monitor simple organism (bacteria, fungi, etc.) responses to zero-gravity and

radiation over time

- Automatic decontamination at end of mission (re-entry)

• Exoplanet telescopes - Measure light curve for a single star for weeks, months, and years

.

Image courtesy of NASA

NanoSail-D:

Solar Sail Testing

O/OREOS:

Space Biology Expts.


PhoneSat 2.5:

Smartphone Satellite


Space material exposure experiments, most recently done on the International Space

Station, can now be carried out on CubeSats as long as sample return is not required.

20

• General perception of limited CubeSat capability

• Statistically high infant mortality

• Many CubeSats are built by “first-timers”

• Aerospace also had issues with reliability in early flights

CubeSat Capability and Reliability

Success Rates

Of First Launches

2000 - 2014

Primary

Success

Some

Operations

Early

Failure

Dead

On

Arrival

Launch

Failure

Data from “The First 100 200 272 CubeSats,” Michael Swartwout, EEE Parts for

Small Missions Workshop, NASA-Goddard Space Flight Center, 11 Sept. 2014

Success rates and mission capabilities improve as CubeSat builders gain

experience.

21

CubeSat Communications: Transmit Frequencies

as of 2014

Total CubeSat Transmitters in Dataset: 172

Amateur Radio 2-meter band (145 MHz) 13

Amateur Radio 70-cm band (435 MHz) 112

Other UHF 13

ISM Experimental 915 MHz (13 from Aerospace) 14

S-Band 13

C-Band 1

X-Band 4

Data from: “CubeSat Radios: From Kilobits to Megabits,” Brian Klofas,

Ground Systems Architecture Workshop, Los Angeles, CA, Feb 2014.

The majority of CubeSats have used Amateur Radio 70-cm downlinks

Some CubeSats, like ours, have 2 transmitters per spacecraft

The majority of CubeSats have used Amateur Radio frequencies.

22

CubeSat Downlink Data Rates as of 2014

Total CubeSat Transmitters in This Dataset: 144

< 9600 baud (Morse Code, 400 baud, 1200 baud, etc.) 85

9600 baud 36

9600 to <1 Mbps (13 from Aerospace) 16

1 Mbps and greater 7

Data from: “CubeSat Radios: From Kilobits to Megabits,” Brian Klofas,

Ground Systems Architecture Workshop, Los Angeles, CA, Feb 2014.

The majority of CubeSats transmit at 9600 baud or slower.

Megabit/second and faster rates are now being implemented

The majority of CubeSats use really slow downlink data rates.

We really want multi-megabit/s rates, and would love gigabit/s rates.

23

Server

Gainesville, FL

#3 Antenna

El Segundo,

CA

#1+4 Antenna

College Station, TX

#2 Antenna

D8 Station

TX Station

FL Station

• Aerospace Ground Network

– 4 dishes deployed in 2012 with

2 more in 2014

– Currently download 5 MB/day

– Automated capability to reduce

costs

Hawaii

#5 Antenna

(FY14)

Mission Control

The Aerospace Ground Station Network

We’ve found that multiple, geographically-separated, ground stations are very

useful for on-orbit checkout, re-programming, and mission ops.

24

Orbital Debris Concerns

Low Earth orbit satellites Geosynchronous

Earth orbit satellites

• The U.S. currently tracks about 20,000 objects in Earth orbit

• The vast majority of these objects are 5 to 10 cm in size

• So far, this class is dominated by orbital debris

The Aerospace Corporation has a Center for Orbital and Reentry Debris

Studies (CORDS): http://www.aerospace.org/cords/

What will happen if we launch hundreds of CubeSats per year over the next

twenty years?

http://www.aerospace.org/cords/

25

• AeroCube-3: - Contained a gas-pressurized balloon to increase drag.

- It failed to deploy fully, but it doubled the drag

• AeroCube-4 Series: - AeroCube 4A contains a deployable drag chute to increase drag 10X.

- Not deployed yet because spacecraft is functional and useful.

- Deployable/retractable wings were used to modify ballistic coefficient.

- Satellite rephasing, using variable spacecraft drag, was demonstrated.

• AeroCube-5A&B: - Both spacecraft contain Tethers Unlimited CubeSat Terminator Tapes.

- Not deployed yet because both spacecraft are functional and useful.

• AeroCube-6A&B: - Both spacecraft have deployed wings that significantly increase drag.

- Satellite rephasing, using variable spacecraft drag, was demonstrated

Aerospace’s Past Efforts to Minimize The CubeSat

Debris Hazard

Changing a spacecraft effective cross-sectional area using attitude control

Can be a useful tool to prevent a collision if enough notice is given.

26

Aerospace Corporation Small Satellite History

1999 2001 2003 2005 2007 2009 2011 2013

OPAL PicoSats (2)

Minotaur I

250 grams

MEPSI

STS-113

800 grams each

MEPSI

STS-116

1.1 and 1.4 kilograms

AeroCube-3

Minotaur I

1.1 kilograms

PSSC Testbed-2

STS-135

3.6 kilograms

MightySat II.1 PicoSats (2)

Minotaur I

250 grams

AeroCube-2

Dnepr-1

998 grams PSSC Testbed

STS-126

6.4 kilograms

AeroCube-4.0 (1)

AeroCube-4.5 (2)

Atlas V, NROL-36

1.3 kilograms

AeroCube-1

Dnepr-1

999 grams

Failed to

Reach orbit

First University

CubeSat Launch

REBR2 (2)

H-IIB

4.5 kilograms

with heat shield

REBR (2)

H-IIB

4.5 kilograms

with heat shield

(Not to relative scale)

(Not to relative scale)

We started building small satellites in 1999.

REBR = Re-entry Breakup Recorder.

27

Aerospace Corporation Active Projects in Small Satellites

2013 2014 2015 2016 2017

AeroCube-7A (1)

OCSD Lasercom AeroCube-9

ISARA

Integrated Solar Array and

Reflectarray Antenna (JPL)

REBR-W-1 (A&B)

REBR Wireless AeroCube-5A&B

AeroCube-6 (2)

Radiation Dosimeters AeroCube-8 A&B (2) R3 - TOMSat (2) AeroCube-7 B&C (2)

Lasercom & Prox-Ops We’ve delivered 4 spacecraft so far this year.

We’ll deliver 3 more before 2016.

AeroCube-5C

28

Spacecraft Launch Date Design Life Operational Life

PicoSat A&B Jan. 26, 2000 5 days 2.5 days (primary batteries drained)

PicoSat C&D July 18, 2000 5 days 1 day after 1-year on-orbit storage (primary

batteries drained)

MEPSI 1 Nov. 23, 2002 7 days 0 days; some beacons received, but no two-

way communications

AeroCube-1 July 26, 2006 7 days Launch Failure

MEPSI 2 Dec. 9, 2006 7 days 3.5 days (spacecraft was put to sleep for

Christmas break and never woke up)

AeroCube-2 April 17, 2007 6 months 1 day (solar charging problem)

PSSCT-1 Nov. 14, 2008 6 months 3.5 months (lost comm. after 109-days)

AeroCube-3 May 19, 2009 6 months 6.7 months (lost comm. after 203 days)

PSSCT-2 July 8, 2011 1 year 4.5 months (re-entered)

AeroCube-4A&B Sept. 13, 2012 1 year 33 months and counting

AeroCube-5A&B Dec. 6, 2013 1 year 18 months and counting

AeroCube-6A&B June 19, 2014 1 year 12 months and counting

Operational Lifetimes of Aerospace Pico/Nanosatellites

Since 2009, we’ve implemented backup communications transceivers, added radiation-

tolerance, and increased ground-testing times to improve mission assurance and

operational lifetimes. AeroCube-2 was our first satellite with solar arrays.

29

• TRL-raising missions

• Orbit control

• New kinds of missions

Mother/daughterships

Satellite augmentation

Distributed assets

Capability progression Radio

Rechargeable power system

Flight computer (robust)

Camera (low resolution)

Magnetic field sensors

Rotation rate sensor (low stability)

Reaction wheels

Torque coils

Tethers

Sun and Earth sensors

Cold gas propulsion

Solid rocket motor

On-orbit reprogrammability

Encrypted communication

Camera (med resolution)

Rotation rate sensor (inertial grade)

Deployable solar panels

Attitude control algorithms

Launch environment logger

Autonomous ground operations

Optical beacon

Proximity radar

Laser communication (10MB/s)

Local Area Networks (LAN)

Continuous Command & Control

Electric propulsion

Autonomous satellite operation

Key:

Multiple Flights

Single Flight

Under Development

2005

2015

Evolving Aerospace PICOSAT

Technologies

30

• Dunsborough, West Australia

• 20 seconds between photographs

T=0s T=20s T=40s T=60s

T=80s T=100s T=120s T=140s

T=160s T=180s T=200s T=220s

Go

og

le M

ap

s

Demonstrates pointing precision of better than 3 degrees.

AC4 tracking a ground point

31

Hurricane Sandy from Medium Field-of-View Camera

Another example of 3o pointing accuracy achieved on AeroCube-4

32

Example: AeroCube-6

• AeroCube-6 is two 0.5U CubeSats.

• Science goal: measure spatial scales of

radiation in LEO.

• Launched: 19 June 2014 aboard Dnepr.

• Orbit: 620 x 700 km x 98 deg.

• Payload: 3 dosimeters on each satellite.

– Including 3 new variants that have never

flown before.

• Nominal sample rate is 1 Hz.

– Dosimeters A1 and B1 can burst at 10 Hz.

• Using differential drag to control

spacecraft in-track separation.

S/C ID# Dosimeter Measures

A 1 Thin Window Low

LET Variant

>50 keV electrons &

>600 keV protons

A 2 Thin Window High

LET Variant

>600 keV protons

A 3 Standard Teledyne >1 MeV electrons &

>10 MeV protons

B 1 Thin Window Low

LET Variant

>50 keV electrons &

>600 keV protons

B 2 Thin Window High

LET Variant

>600 keV protons

B 3 High LET Variant >10 MeV protons

Dosimeter

Payload:

AeroCube-6A and 6B are 0.5U CubeSats with radiation-monitoring payloads.

The A3 version of the dosimeter is commercial, off-the-shelf.

33

Half of the AeroCube-6 “1U” configuration • AeroCube-6, alone

AeroCube-6 uses the 0.5U form factor, plus two deployable wings that include

experimental solar cells. The top is anti-sun pointing.

The spin axis can be aimed 30o off of sun nadir. This enables differential drag

between the two spacecraft to control inter-satellite spacing.

34

The Making of a Binary Satellite • Mating two 0.5U AeroCubes

The wings of each AeroCube-6 wrap around the body of the other, creating a

package that conforms to the 1U CubeSat standard.

Nesting two 0.5U spacecraft together enables launch as a single 1U CubeSat.

This spacecraft has 4W of solar power in sun-pointing mode.

35

Space Weather Monitoring

A1: >50 keV e-, >600 keV H+ A2: >600 keV H+

AC6 investigating spatial and temporal behavior of radiation environment.

Thousands of orbits of data have been collected thus far.

South Atlantic Anomaly

This 1U mission was used to advance the TRL of modified dosimeters. One

journal article based on flight measurements has already been submitted.

36

Example: AeroCube-7A,B,&C

• Funded by NASA’s Small Satellite Technology Program -Optical Communications and Sensors Demonstration (OCSD)

• Original Goals: - Demonstrate a 5 Mbit/s laser downlink from a 1.5U CubeSat

- Demonstrate proximity operations using 2 1.5U CubeSats

- Demonstrate on-orbit propulsion for a CubeSat

• Current Goals: - Test attitude control accuracy using AC7-A

- Test laser downlink at 5 to 50 Mbit/s using a single 1.5U pathfinder (AC-7A)

- Make software and hardware improvements, if time permits, to AC-7B&C

- Demonstrate 100+ Mbit/s laser downlink in early 2016 using AC7-B&C

- Demonstrate proximity operations and propulsion using AC-7B&C

- Demonstrate 3-axis attitude control with at least 0.1o pointing accuracy

This mission requires 3-axis attitude control with at least 0.1o pointing accuracy.

The single pathfinder flight will be used improve overall mission assurance.

“Fly as you fly”

37

Laser Transmitter

• OOK modulation at 5 - 200 Mbps

• 5 W output power

• Efficiency: > 20% wallplug

• DT ~ 250 C

• 0.35 degree FWHM beamwidth

• 10 x 10 x 2.5 cm footprint

TopView:2ndstageampside

2ndstageamppumpdiode

Pump/signalcombiner

Isolator

Side view: fiberoptics with integrated electronic controller board

Electronic controller board

Tx aperture

7A Flight Unit Lab Prototype Unit

AeroCube-7 (OCSD) is the most complex CubeSat we’ve built so far.

The avionics and attitude control system will be used in future AeroCubes.

The laser “flight unit” will be a flight prototype unit for the future flights.

38

AeroCube-7A As Delivered (Stowed Wings)

Laser Retro-

reflecter

Stowed

Wing

LED Beacon

2-Axis Sun

Sensor

Earth Horizon

Sensor

Star

Tracker

Camera

GPS

Antenna

Medium Gain

Comm. Antenna

Laser

Rangefinder

2-Axis Sun

Sensor

AC-7B&C will also have an additional steam propulsion module. Proximity operations

will use variable drag and warm gas propulsion for maneuvering.

39

PI: Renny Fields, The Aerospace Corporation

LMPC (AeroCube 9)

Infrared Linear Mode Photon Counting CubeSat

Co-Is: James B. Abshire, Xiaoli Sun; GSFC Jeffrey D. Beck; DRS-RSTA

Key Milestones

Objectives • Demonstrate that an IR detector with photon

sensitivities at 1, 1.5, & 2 microns with linear mode response can be achieved in a Earth observing orbit over a meaningful life with on-orbit radiation exposure

• Demonstrate that the Infrared Detector can be integrated with its cooler and accommodated with radiation and IR test devices within a 3U CubeSat

• Measure detector dark current and radiation dosage throughout the mission

• Analyze results in terms of detector suitability for candidate Decadal Survey missions

Approach • Integrate a 16 element detector & preamplifier chips

into an integrated dewar cooler assembly previously used on a Black Brandt rocket flight

• Adapt detector/cooler assembly into the Aerospace 3U cubesat

• Include optical test sources & adapt cubesat avionics package for this experiment

• Operate experiment in space for a year [?] with test sources, sunlit Earth &/or ground beacons as resources permit

TRLin = 5

• Program Start 08/2013

• System Requirements Review 09/2013

• Preliminary Design Review 12/2013

• Critical Design Review 05/2014

• Test Readiness Review 02/2015

• Pre-ship Review 12/2015

• Mid-flight Mission Review L+6 mo

• Final-flight Mission Review L+1 yr

LMPC CubeSat

1 Dewar 2 Sterling cycle cooler 3 Reaction wheels 4 IDCA power pack 5 Avionics power pack 6 Avionics 7 Sensor FOV 8 LMPC chip (not visible)

40

Satellite Class RF Output Power

(W)

Data Rate for 2-m dia.

Receiver (Mbps)

Data Rate for 4-m dia.

Receiver (Mbps)

Microsatellite 1.4 – 12 2.8 – 24 11 – 97

Nanosat/CubeSat 0.30 – 2.5 0.61 - 5.1 2.4 – 20

Picosatellite 0.065 – 0.53 0.13 – 1.1 0.53 – 4.3

Femtosatellite 0.015 – 0.12 0.031 – 0.24 0.12 – 0.97

Attosatellite < 0.025 < 0.051 < 0.20

2500-km range, 10-dBi transmit antenna,

RF output @ 25% of orbit average bus power

In LEO, microsatellites can have 10’s of Mbps data rates,

Picosatellites can attain a few Mbps

Downlink Data Rates

41

Theoretical Ground Resolution

A 5-cm aperture can provide 4 to 6-m ground resolution at 500-km altitude

A 28-cm aperture on a 27U CubeSat could provide 1-meter resolution.

42

Earth Coverage vs. Altitude and Elevation Angle

Only 3 GEO satellites are required for complete Earth coverage,

But more than 50 are required in LEO.

43

Constellation

Morphing:

These are all the same Walker constellation, but with different satellite phase factors.

44

The Future of Small Satellites

• Microsatellites will become even more capable

• Nanosatellites (CubeSats) will perform operational missions

• Picosatellites will perform operational missions

• Useful Femtosatellites will be flown

• Moore’s Law will continue for at least another decade

• Photonics integration is on path exceeding Moore’s Law

• Miniaturized RF technologies will continue to develop

• Sensors will continue to shrink in size, mass, and power

• Networking will infiltrate ground stations and spacecraft

• ITSNTS: It’s the system, not the satellite

Small satellites in all size classes will grow in capability

45

Near-Term: Highly-Capable CubeSats

• Watts of orbit average power

• Data rates > 1 Mbps

• Orbit change capability

• Pointing to < 0.1 degrees

• 5-meter ground resolution

Cubesats from “1/2” U through “6U” size will proliferate. 12U (20 x 20 x 30 cm) and 27U (30 x 30 x 30 cm) CubeSats are on the horizon.

Predicted in 2009:

• Proliferation of 3U and 6U CubeSats

• 200 to 400 CubeSats per year

• 10 to 20 W of orbit-average power

• Required orbit change capability

- Deorbit, collision avoidance

• 3-axis pointing to < 0.02 degrees

• 2-meter ground resolution (6U)

• Commercially-available 5-meter visible ground resolution (PlanetLabs)

New Predictions:

46

Mid-Term: Satellite Assistants (as predicted in 2009)

• Augment CPU and/or memory

• Add new receive capability

• Add low-power cross-links

• Add on-orbit inspection capability

• Interplanetary flybys - Extra “eyes”

- Impacts for spectral analysis

Host Satellite

with km-range

LAN (optical,

microwave, or

mm-wave)

Micro/nanosat

LAN

Existing Uplink New Uplink

Satellite assistants will augment legacy spacecraft. Adoption date still 5 to 10 years in the future.

47

• Plug-and-Play modules with electronics, mating ports, and actuators

- Mass-producible modules

- Spacecraft can grow in time as more modules are added

- Spacecraft geometry can change to adapt to new missions

- Spacecraft electronics can be upgraded incrementally over time

• Applications

- Large geosynchronous bus for “plug-and-play” payloads

- Phased array that grows with time

- Phased array with variable aperture

- Spacecraft that physically disperse

- Spacecraft that interchange

components as needed

Long-Term: Modular Reconfigurable Spacecraft

Reconfigurable spacecraft offered a new space paradigm, and still do!

48

Long-Term: Free-Flying Reconfigurable Spacecraft

• Sparse aperture arrays

– UHF through mm-wave antennas

– Kilometer-scale effective diameters for narrow beam widths

– Hundreds-to-thousands required for good antenna pattern

J.E. Pollard, C.C. Chao, and S.W. Janson, “Populating and Maintaining Cluster Constellations in Low Earth Orbit,” AIAA paper 99-2871, 35th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Los Angeles, CA, June 1999.

U.S. Patent

6,725,012

Earth

Normal Vector of

Cluster Plane

Nadir Vector

(Towards center of Earth)

30o

Normal Vector of

Reference Orbit

Reference

Orbit

Subsatellite Orbit 60o

Cluster plane

at t=1/2P

Cluster plane

at t=0

Two papers and one patent on local cluster creation and maintenance.

49

Formation-Keeping in Local Clusters

• Cluster rotates once per orbit as a rigid body

• Subsatellite orbit correction burns occur 3 times per orbit

• DV requirements are modest

– 67 m/s/year for 1-km radius cluster at 700-km altitude using 10 cm

positional accuracy and 1 mm/s velocity accuracy

– Average impulse is 4 mN-s/kg for 1-km radius at 700 km altitude

– DV is a function of position and velocity measurement accuracy

– DV drops rapidly with altitude

Yearly velocity increment requirements are modest for 1-km radius in LEO

51

Summary

• About 300 CubeSats have been launched

• CubeSat launch rates could exceed 300 per year in a few years

• This is a world-wide phenomenon

• Plenty of launch opportunities exist each year

• You can fly new technologies at reasonable cost

• You can design, build, fly, and get flight data within 1 year

• “Fly as you fly” has become a viable technology development option

• The downside is that we will have many more spacecraft in LEO

• We will need to add deorbit devices to future CubeSats in higher orbits

• The Aerospace Corporation has, and is, flight-testing deorbit devices

• The Aerospace Corporation has flown 25 small satellites since 2000

• We use the “fly as you fly” approach to develop new bus technologies

• We will continue to do so for the foreseeable future

52

Acknowledgment I thank The Aerospace Corporation’s Independent Research

and Development program for supporting

research in small satellites.

I also thank the Space Test Program, NASA, and the DoD for supplying funding

and flight opportunities.

Image of U.S. Space Shuttle Atlantis taken by Aerospace Cubesat PSSCT-2.

cubesat technology and systems dr. siegfried...

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