ASTEP Life in the AtacamaCarnegie Mellon Limits of Life in the Atacama: Investigation of Life in the Atacama Desert of Chile Communication System Design Michael Wagner The Robotics Institute Carnegie Mellon University

ASTEP Life in the AtacamaCarnegie Mellon Requirements Transmit science data with Mars-relevant restrictions Latencies of several minutes MSL bandwidths Robust links important in treacherous Atacama terrain Be able to debug and collect enough data for 2 nd and 3 rd year improvements

ASTEP Life in the AtacamaCarnegie Mellon Component Overview Rover to mobile camp Operations (uplink / downlink) channel Mars-relevant bandwidth Reliability and range Debugging / telemetry logging channel High-bandwidth Less range acceptable Mobile camp to server in Pittsburgh At least as fast as ops channel Pittsburgh to science team

ASTEP Life in the AtacamaCarnegie Mellon Daily Communications 1. Direct to Earth (DTE): Critical downlink data required to do science planning 37+ Mb per sol in MSL scenario 2. UHF Downlink: Remaining downlink data 58 Mb per sol in MSL baseline scenario 3. Direct from Earth (DFE): Uplink commands for next sol 1 Mb per sol in MSL scenario

ASTEP Life in the AtacamaCarnegie Mellon Sample Communication Schedule Assumes: 9.6 kbps link Baseline MSL

ASTEP Life in the AtacamaCarnegie Mellon MSL Telecom Orbiter Scenarios Three UHF scenarios, based on telecom orbiters Baseline: MSL and MRO 58 Mb per sol Mid-range: MSL and PREMIER 155 Mb per sol Best case: MSL and Guglielmo Marconi Orbiter (GMO) 436 Mb per sol

ASTEP Life in the AtacamaCarnegie Mellon Keeping up with MSL Iridium Ham radio, Radio modems Cellular INMARSAT

ASTEP Life in the AtacamaCarnegie Mellon Current System Design Mobile Camp Ops channel is patched into ISP Insert latency here? Rover Debugging: ~1 Mbps, Up to 10 km, Intermittent availability, No latency Ops: ~10 kbps, Up to 50 km, Scheduled availability, Insert latency here? ISP Relay ISP: at least 10 kbps, Scheduled availability, No latency May use 2.4 GHz wireless Ethernet

ASTEP Life in the AtacamaCarnegie Mellon Current System Design NASA Ames Univ. of Tennessee NASA JSC CMU RI Univ. Catolica del Norte CMU Biology ISP Relay ISP: at least 10 kbps, Scheduled availability, No latency Internet Data formatted into science interface, released and archived Commands collected and uplinked

ASTEP Life in the AtacamaCarnegie Mellon Implementation Plan Construct a “bit budget” How much data will each instrument generate? What is the priority of each instrument’s data? DFE: needed for science planning UHF: lower priority

ASTEP Life in the AtacamaCarnegie Mellon Implementation Plan Evaluate operations channel options 140 MHz (2 m) ham radio equipment 900 MHz radio modems Test in noisy metro environment We hope to understand: Relationship between SNR, distance and terrain Probability of multipath interference Directionality of signal

ASTEP Life in the AtacamaCarnegie Mellon Implementation Plan Compare ISP relay options Best option depends on infrastructure available at field site INMARSATIridiumCellularHam Radio Pros Up to 64 kbps Reliable link No infrastructure needed Portable Reliable link No infrastructure needed 14.4 kbps + Cheap 9.6 kbps Long range Cons Expensive Fast options are bulky Only 2.4 kbpsRequires cell infrastructure Multipath

ASTEP Life in the AtacamaCarnegie Mellon Implementation Plan Introduce Mars latency to rover comm software Unlike other systems (e.g. PlanetNet) we are only introducing latency into two applications Rover telemetry manager Command uplink software So, we only need to alter the OSI application layer We can use standard networking protocol software