CubeSat Laser Communications

Transceiver for Multi-Gbps Downlink.

NASA SCaN SBIR Workshop: Optical Communication

9/13/17

Ref: 31st Annual AIAA/USU 2017 Conference on Small Satellites

Paper SSC17-XI-09

13605 Dulles Technology Dr.Herndon, VA 20171(703) 471-7671www.fibertek.com

2

Who is Fibertek?

An Optical Instrument Aerospace company

Fibertek has provided >100 systems deployed in UAVs, DoD vehicles and Spacecraft

Aircraft and UAVs Spacecraft and Space Station

Ships and SubmarinesTerrestrial Vehicles Ground

❖ We develop Optical Instruments and subsystems for customer platforms

3

Fibertek is a Space Flight Company:

CALIPSO & ICESat-2

❖ NASA /BATC

❖ Cloud and Aerosol Lidar

❖ NASA ESSP 3-year mission

❖ 11+ years of 24/7 365 days/year

since 2006

❖ NASA ICESat-2 Instrument

❖ Supplied Lasers & Photon

Counting Electronics

❖ 2018 Launch

Photon Counting

Electronics

(120 PMT Channels)

Lasers

CubeSat Laser Com

5

Motivation

❖ Space Lasercom offers Large Bandwidth, Low SWAP.

❖Technology is maturing – TeSAT, Japan and NASA Demos

❖ Key Questions ❖ Can it be compact?

❖ Offer substantial bandwidth performance increase?

❖ Be affordable for USG and commercial operational use?

6

Fibertek Approach: Develop

Multi-function Optical Terminal

Strategy

❖ Develop Small, Low cost multi-purpose laser com terminal

❖ Support variety of NASA missions

❖ Support Ring and Mesh topologies

❖ Use TRL-9 Tech for Coarse Pointing

❖ Applications:

Sensor data ingress, inter sat network, downlink to earth

Small 2 kg Optical

terminal on a 2D Gimbal

Mount 1 or more unit to for

sensor aggregation, planetary

uplink, network cross link

Multi-function Orbiter

Resource

7

NASA SBIR : CubeSat Lasercom Terminal for

Deep Space

❖ Comprehensive functionality in compact, thermally stable package

❖ Precision pointing ensured by:

Fibertek’s multiple layers of isolation and FSM

CubeSat coarse pointing capability and platform stability

❖ Sufficient to support laser com from 1AU distances

6U CubeSat (XB1-Bus)Blue Canyon Technologies

X

Y

Z

CubeSat

Lasercom

Terminal

2x XACT

(0.5U ea.)

Body-Pointing for

coarse steering (3s < ±0.2) 1 10 100 1000DC

Frequency (Hz)

Base

Motion

Tracking

Active

Jitter Control

Passive

Isolation

On

-orb

it V

ibra

tion

PS

D

Pointing & Tracking

2-stage Nested Control Loop

Z20.01-9956 - 1U CubeSat Lasercom Terminal for Deep Space Communication

8

Integrated CubeSat Lasercom

Pump Laser DiodeFor Fiber-Amplifier

MODEM &Processor Board

Optical Transceiver

Card

1.5-mm FiberAmplifier Lasercom

Transmitter

Transmit/ReceiveOptical Head,

with Integrating Pointing Stab.

8”

4”

4”

Optical Engr. 55 (11), Nov. 2016

❖ Modular and Scalable

❖ 1.5 mm downlink (LEO 10G via OOK, 100 Mbps PPM

❖ 1 mm uplink (1G)

❖ Point ahead - PSD or FPA beacon sensors.

❖ Future Plans – Update to include 1.5um receiver in 2018

❖ Laser power from 0.5 to 2 W

SWaP ~ 2 kg, Power ~22 W

9

Optical Head prototype, designed, built

and performance tested

PiezoFSM

Telescope Primary

f = 64 mm

Secondary(f = 10 mm)

CMOSFPA

(1-um uplink)

FiberCollimator

1.5-umFiber LaserDownlink

Transmitter

Piezo cable

❖ Prototype NASA SBIR (AMES) Space Terminal Optical Head

❖ Prototype tested in the Lab

▪ Verified for transmit/receive optical parameters (wave-front, throughput)

▪ Demonstrated closed loop pointing control to ~20-mrad.

❖ Vibe Tested Optical Head Assy. (10Grms)

❖ Laser Transmitter as a separate 2W card, leveraging Fibertek’s space design

10

Telescope Optical Characterization

❖ Telescope measured to be 1/10 wavefront error at 1064nm

❖ Supports deep space laser communications, long distances

0 1.5 3 4.5 6 7.5 9 10.5 12 13.5 15

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Radius From Centroid in µm

Diff. Limit

0.0000, 0.0000 (deg)

0.0000, -0.1000 (deg)

0.0000, 0.1000 (deg)

-0.1000, 0.0000 (deg)

0.1000, 0.0000 (deg)

0.0000, -0.1500 (deg)

0.0000, 0.1500 (deg)

-0.1500, 0.0000 (deg)

0.1500, 0.0000 (deg)

Fibertek, Inc.13605 Dulles Technology Drive

Herndon, VA 20171

CubeSat Telescope v23.20 - TOL - new fringe.ZMXConfiguration 1 of 1

Fraction of Enclosed Energy

FFT Diffraction Encircled Energy

CubeSat telescope v23.20 - Zernike Fringe - #0068/2/2016Wavelength: PolychromaticSurface: Image

Measured Wave-front. P-V of 0.573l, and

RMS of 0.108l at 1064nm.

(If scaled to wavelength 633nm, PV & RMS

are 0.963l and 0.182l, in line with vendor

measurement using interferometer)

Optical Path thru Terminal

11

Passive Isolation Design Verified with 10

Grms random vibe

y-axis

x

y

z

Space Optical TerminalMass mock-up in Vibe Test

z-axis

NASA GEVS profile

▪ NASA GEVS (Acceptance) 10Grms criteria as input ASD

▪ Test & Calibration via Vibe Test of mass mock-up (right)

▪ Significant damping obtained to launch loads.

▪ No damage/change, Verified by pre/post vibe freq. response test.

12

Fine Pointing/Tracking: Initial Results

Optical

Terminal

-200

-150

-100

-50

0

50

-100 0 100 200 300 400

Locked

Unlocked

<20-urad radius

65-urad radius

Jitter BW

= 50 Hz

Duo-Lateral PSD

❖ Duo-Lateral PSD▪ NEP ~ -55 dBm, uplink beacon trade

▪ Improving the control-algorithm

▪ Developing low-noise analog electronics

❖FPA-sensor: ▪ Limited to ~10Hz, by USB3 interface

13

Summary: CubeSat Laser com Terminal

❖ Fibertek has made significant progress to enabling High Performance,

Ultra-compact, Low Swap-C Space Laser Com

❖ Design Modular and scalable to long ranges

❖ Can support commercial thru NASA Class A/B mission quality

❖ Future Work▪ Complete prototype in 2017

▪ Prototype Flight planned for 2018

▪ Bidirectional Capability in Next Generation ~ 2018

Shared-Aperture TelescopeTransmit / Receive

PiezoFSM

Telescope

Primaryf = 64 mm

Secondary

(f = 10 mm)

CMOSFPA

(1-um uplink)

Fiber

Collimator

1.5-umFiber LaserDownlink

Transmitter

Piezo cable

CubeSat LasercomTerminal 2U

Small/Large Sat Space Gimbal