Planet Labs Ground Station Network

Bryan Klofas [email protected] 21 April 2016 13th Annual CubeSat Developers Workshop Cal Poly SLO Intro to Planet Labs Space Startup

• Planet Labs is driven by a mission to image the entire Earth every day, and make global change visible, accessible, and actionable • 300+ employees • Based in , CA ○ Satellite offices in Lethbridge and Berlin (RapidEye) • $183 Million in VC funding

• 133 satellites successfully launched • 2 rocket failures with 34 satellites lost (Orb-3, SpaceX-7) • 100 satellites successfully deployed • 32 satellites launched and waiting on ISS (Orb-4, OA-6) • 36 satellites still in orbit

Slide 2 A Typical Satellite Basics

• 3U form factor with 6 fold-out panels • CCD camera • 20km swath width at 3.5m GSD from 400 km • Onboard JPEG2000 compression • 13 Hardware Revisions • COTS SSD • Ubuntu

Slide 3 A Typical Satellite UHF Radio

• UHF radio: TI wireless MCU • Power amplifier: RFMD 1 watt output • Monopole antenna

• Ground station is identical hardware and software • Presented at CubeSat Summer Workshop 2014 ○ Design will be open-sourced soon (up and downlink encrypted and secured) ○ Follow-up presentation at SmallSat 2016

Slide 4 A Typical Satellite S/X Radio

• S-band uplink ○ 250 kbps BPSK ○ NACK-based file protocol ○ Needed for downlink ACM • X-band downlink ○ 12.5 Mbps up to 100+ Mbps ○ 8.2 GHz at 2 watts ○ DVB-S2 standard with Generic Stream Encapsulation ○ Fixed 24 Mbaud symbol rate ■ Upgrade to 56 Msps on next sats ○ Variable modulation: QPSK, 8PSK, 16APSK, 32APSK ○ Variable FEC: 1/4 up to 9/10 ○ GSE allows IP connectivity to satellite

Slide 5 Satellite Control Open 9am-5pm M-F

• “Spaceship Captains” operate all satellites ○ Mostly anomaly resolution and testing ○ Normal operations: “Automate ourselves out of a job” ○ If they all call in sick, everything still works (for a few days) ○ 24/7 on call support for emergencies • Mission Control is fully automated, runs on AWS ○ Scheduling happens frequently ○ All software done in house, allowing us to fix bugs quickly ○ No existing products fit our needs • System is fully automated and tolerant of missed passes ○ Greatly reduced operational costs vs. 100% downlink guarantee ○ Missed data is downloaded next pass ○ Decreased operational costs allow smaller team to manage satellites and have a “normal” life (no graveyard shifts) ○ Continuously developing/updating software

Slide 6 A Typical Ground Station UHF

• TT&C only • Uplink at 450 MHz, up to 100 Watts • Downlink at 401.3 MHz • Encrypted 4800 baud GFSK • Yaesu G-5500 • Separate M2 yagis • Open-source radio design

Morehead State University

Slide 7 A Typical Ground Station UHF Ranging

• When not scheduled to talk with a satellite, each ground station opportunistically ranges with all available satellites • Post processed errors at 1 day: ○ JSpOC: 1 to 3km ○ UHF ranging: 0.5km • Ranging data fed back into Space Data Association

• Open orbit data at http://ephemerides.planet-labs.com

• See AAS 15-524, “Orbit Determination and Differential-Drag Control of Planet Labs CubeSat Constellation,” by Cyrus Foster, Henry Hallam, James Mason

Slide 8 A Typical Ground Station Washington State

• 5m dish • Combined S/X feed • Up to 100 W S-band uplink • 29 dB/K at X-band • Integrated UHF feed on other dishes • Dektec PCI DVB-S2 receiver card

Brewster, Washington

Slide 9 A Typical Pass Washington State talking with Flock 2b, March 16th • 55 degree max elevation • X-band lock for 435 seconds = 7.25 min • Variable data rate up to 84 Mbps • Modcod up to 24 • Downloaded: 4.2 GBytes = 650 pictures = 170k sq km * • Pictures uploaded to AWS for rectification

* Including frame overlap, clouds, ocean, etc. Only 20- 50% of downloaded pics are acceptable for consumers Slide 10 An Average Day New Zealand schedule for March 16th UTC

Spacecraft ID

Slide 11 An Average Day New Zealand on March 16th UTC

• 33 passes scheduled for 16 satellites • 25 passes successful, 75% ○ Satellite not transmitting or pointing correctly, ground station pointing error, software bugs • 99 GBytes downloaded = 23k pictures = 6M sq km *

Slide 12 The Ground Station Network Global View

HSD + LST

• 7 CGC 5m dishes • 7 Omnispace/ICO 7.6m dishes • 4 L3 Datron 5m dishes • 32 yagi stations

Slide 13 A Typical Day Global View

Spacecraft ID

Colors indicate ground station Slide 14 A Typical Day March 16th UTC

● UHF: ○ 333 passes scheduled, 239 good passes, 71% ○ 97k commands received ● X-Band: ○ 207 passes scheduled, 157 good passes, 76% ○ 559 GBytes downloaded = 161k pics = 39M sq km * ○ CONUS is 8M sq km ● Best day: 777 GB

Slide 15 Mission 1 Image all land, every day

• Image all the earth, every day • 6 TBytes of land images to download every day ○ Equipment already installed in Iceland ○ More locations to come later this year ○ Continuous improvement process ○ Increasing downlink rate past 75% allows us to download oceans, ice, etc

Slide 16 Questions?