Deep-Space Telehealth Delay Simulator

Telehealth Link Target

Mission Timeline

Mission day (orbital phase) 0

Medical Data Payload

Payload type

Link data rate 4 kbps

Link Status

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Distance

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One-way light delay

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Round-trip delay

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Payload transfer time

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Total time until Earth has the full data

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How it works

Two independent, additive delays govern any deep-space medical link — this simulator computes both from real orbital mechanics rather than a fixed number:

Earth-Mars distance (coplanar circular approx):
  d = sqrt(rE² + rM² − 2·rE·rM·cos(θE − θM))
  rE = 1.000 AU, rM = 1.524 AU
  θE = 2π·day/365.25,  θM = 2π·day/686.98

Propagation delay (speed of light, fixed by distance):
  t_prop(one-way) = d / c,   c = 299,792.458 km/s

Transmission delay (bandwidth-limited, independent of distance):
  t_xfer = payload_bits / data_rate

Total one-way delivery:  t_total = t_prop + t_xfer

Mission day moves Earth and Mars along their orbits, so distance — and therefore delay — genuinely varies between ≈54.6M km (opposition) and ≈401M km (conjunction), giving a one-way light delay of roughly 3 to 22 minutes for Mars. The Moon is modelled at its near-constant ≈384,400 km, a ~1.28 s one-way delay.
Payload + data rate model the second, independent bottleneck: even with zero propagation delay, pushing a 300 MB imaging batch down a Deep Space Network downlink measured in kilobits per second takes real time. NASA's actual DSN links to Mars run from a few kbps up to a few Mbps depending on distance, antenna and mission priority — the slider spans that realistic range.
Recommended mode is a simplified round-trip-delay heuristic mirroring real mission-medicine guidance: under ~3 s the crew can hold a live conversational video call; under ~4 min a delayed video/audio exchange is still watchable; up to ~40 min, store-and-forward telemetry (ECG, labs, imaging) with asynchronous physician review is the working model; beyond that, onboard AI must render an autonomous first-pass diagnosis and only notify Earth afterward, because no round-trip consultation can happen in clinically useful time.

This is exactly why the two proposals discussed for real Mars missions — AI-assisted diagnosis and pre-loaded telemedicine protocols — exist: light-speed alone puts a hard floor under any live consultation the moment the crew leaves cislunar space.

Sun Earth Mars Moon Signal pulse

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