Live signal transmission

How a continuous high-resolution Earth view could travel from the lunar surface back to viewers on Earth. These are conceptual options, not a chosen system.

Direct path

Line of sight from the lunar surface to Earth

From a near-polar site on the Moon's Earth-facing side, Earth stays almost fixed above the horizon — which keeps a transmitting antenna pointed at the same patch of sky for long stretches. A direct downlink to ground stations on Earth is the simplest route: no intermediaries, just the open distance between the two worlds.

  • Roughly 1.3 seconds of one-way light delay, set by distance alone
  • Best raw image quality when the link budget allows it
  • Limited to the hours when a given ground station can see the Moon
Moon locations Camera systems
Twenty years of hourly Earth positions in a candidate site's lunar sky — the compact window a fixed antenna would cover
What a fixed dish on the Moon must cover: twenty years of hourly Earth positions over the real skylines of the two featured sites (JPL DE440 + NASA LOLA). The target barely moves — the antenna, like the camera, points at one small patch of sky.

Relay path

Relay satellites in lunar orbit

When a ground station cannot see the Moon, or the terrain blocks the direct view, a satellite in lunar orbit could pick up the signal and pass it on. A relay extends coverage toward continuous service and softens the gaps a single direct link would leave — at the cost of an extra hop and a more complex link to design and depend on.

  • Coverage during windows when no Earth station has line of sight
  • An additional hop adds latency and another point that must stay healthy
  • Treated here as an option — exax does not operate or claim a relay
Project concept Power supply
The sub-Earth point's two-century wander as a scatter cloud — the Earth-facing geometry that direct and relay links share
The geometry every link shares, direct or relayed: two centuries of the sub-Earth point's wander (JPL DE440, 1900–2100), bounded within ±8.14° east–west and ±6.87° up–down. A relay adds coverage when Earth stations lose sight of the Moon — it does not change this stable Earth-facing geometry.

Shared infrastructure

Integration with existing lunar communications

A growing set of deep-space and lunar communication systems already carries data between the Moon and Earth. Rather than build everything from scratch, the concept assumes the camera's stream could ride on this established infrastructure where capacity is available — gaining redundancy and reach without reinventing the network.

  • Reuse of proven ground-station and deep-space links instead of bespoke hardware
  • Shared capacity means schedules and bandwidth are not exclusive to one feed
  • A high-resolution live stream is demanding, so available capacity is the constraint
Getting there Watch
Computed figure: Earth's monthly libration arc above the Gioja East Highland skyline
The stream's subject, over one month: Earth's libration loop above the Gioja East Highland skyline — computed from JPL DE440, three real phases, disc to scale. The patient, predictable signal that existing deep-space networks would carry.

Comparison

Trade-offs between the three paths

Each route balances image quality, latency, and reliability differently. The right answer depends on the chosen site, the available infrastructure, and how much continuity the live view needs.

Signal quality

A direct downlink can offer the cleanest, least-compressed image when the link budget allows. A relay or shared network may need more compression to fit available capacity, which softens fine detail.

Latency

Earth and the Moon sit roughly 1.3 light-seconds apart, so the direct path is already near that floor. Every relay or extra hop adds a little more delay on top — small, but real for a live feed.

Reliability

A single direct link goes dark whenever the ground station loses sight of the Moon. Relays and shared infrastructure add redundant routes, so the view can continue when one path is unavailable.

Earth and the Moon drawn at true relative size and true mean separation, with the direct downlink beam and its 1.3-second light time
The distance behind every trade-off, drawn to true scale: both worlds and the 384,400 km between them at real proportion. Light needs about 1.3 seconds one way — the floor no path can beat; every relay hop re-crosses this same gap.
Project concept Camera systems

Help carry the signal home

Returning a live high-resolution Earth view from the Moon is one of the hardest parts of the concept. Follow how the transmission question develops, or help bring a permanent window on Earth a step closer.

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Earth above the lunar horizon, seen from the surface of the Moon