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November 10, 2011

Telerobotics and Telepresence from Earth-Moon Lagrange Points

Low-Latency Lunar Surface Telerobotics and Telepresence from Earth-Moon Lagrange Points by Dan Lester (27 pages)

* Latency smaller than our “cognitive timescale” leads to ”telepresence”
* When 2-­‐way latency exceeds our “cognitive timescale”, the brain works differently. “Move and wait” to avoid instability – inefficient.

Cognitive Timescale is about half of one second

• Human reaction time for visual stimulus is ~200 ms, ~150 ms for audio (probably smaller for haptic)
• High performance online gaming depends on latencies of less than 100-­‐200ms
• Telerobotic surgery (cutting, suturing, knot tying) requires less than 500 ms
• Telerobotic mining (driving bulldozers, drilling) assume ~500 ms
• Drone piloting with latencies of ~1000 ms (but flying is easy!)

Two way communication range within the cognitive time is 75,000km




Tying a knot with 2 seconds latency can take ten minutes

Lagrange points are the best for lunar teleoperation

400 ms delay from the Earth-­‐Moon L1/L2

Earth-­‐Moon L1/L2 offer cognitive connection between human brain and lunar surface equipment.

Operating robots from closer distances offers very few advantages.

Earth moon L1/L2 is enabling site for lunar surface telerobotics
• Latencies less than 6 times from Earth, 400 ms -­so cognitive operations
• Continuous access to the near-­or far-­‐side (except poles …)
• Communication LOS with Earth is stable and reliable
• Little orbit maintenance needed – of order tens of m/s/yr
• Control options for multiple surface sites
• Avoid putting humans in deep gravity wells in near term

People can still go the lunar surface.

Telepresence strategy is extensible throughout the solar system For Mars, ops from Phobos or Deimos
–(Deimos-­‐to-­‐Mars -­‐ latencies of 130 ms.)

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