1. The signal and the silence

Carl Sagan’s Contact is about a radio astronomer who detects a signal from somewhere else. The book spends as much time on the politics of who gets to listen and who gets to speak as it does on the science. That is the right frame for spectrum and remote sensing licenses. The desktop must both listen to commands and, if it carries sensors, look at Earth. Both actions require permission.

Entry 285 covered launch licensing. This entry covers the operational licenses that allow the desktop to communicate and observe.

2. Spectrum as a finite resource

Radio frequencies are shared. Satellites, aircraft, ships, emergency services, and broadcasters all need spectrum. Without coordination, signals interfere and nobody is heard.

The International Telecommunication Union divides spectrum into bands and allocates them to services such as:

  • Fixed satellite service.
  • Mobile satellite service.
  • Earth exploration satellite service.
  • Space operation service.
  • Amateur satellite service.

The desktop will likely use bands in S-band, X-band, or Ka-band for telemetry, command, and payload data. Each band has different propagation characteristics, antenna sizes, and regulatory status.

3. The ITU coordination process

Before a satellite can use a frequency, its operator must coordinate with other users of the same band. The process involves:

  • Filing advance publication information with the ITU.
  • Submitting detailed coordination data, including orbit, frequencies, power, and antenna patterns.
  • Negotiating with administrations whose satellites might be affected.
  • Obtaining a favourable finding before launching.

Coordination can take years for congested bands. For small satellites in less congested bands, the process may be shorter, but it still requires planning.

4. National spectrum licensing

The ITU coordinates internationally, but actual licenses are granted by national regulators. In the United States, the FCC grants licenses for non-federal satellite communications. The license specifies:

  • Frequencies and bandwidth.
  • Power limits.
  • Modulation and emission characteristics.
  • Orbital positions or parameters.
  • Authorized earth stations.
  • Reporting and compliance requirements.

The desktop’s communications architecture must match the license. Changing frequencies or adding earth stations after launch usually requires regulatory approval.

5. Remote sensing license

If the desktop carries a camera or other Earth-observing sensor, it may need a remote sensing license. In the United States, NOAA licenses commercial remote sensing space systems.

The license considers:

  • Spatial resolution of the sensor.
  • Revisit rate and coverage.
  • Data policy, including who can access the data and under what conditions.
  • Shutter control: the government’s ability to restrict imaging of certain areas during certain periods.
  • Foreign involvement or foreign customers.

A sensor that images only the desktop itself or the space around it may not need a remote sensing license. A sensor that images Earth probably does.

6. Data policy and sovereignty

Remote sensing data is not just a product. It is a political object. Governments care about:

  • Whether high-resolution imagery of their territory is sold to foreign customers.
  • Whether imagery is available in near-real time.
  • Whether the operator can be compelled to withhold data.

The desktop’s data policy should be designed with these sensitivities in mind. A customer who buys imagery and then finds it unavailable due to shutter control will not be happy.

7. Radio quiet and orbital neighbours

Spectrum coordination is not only about paperwork. It is also about behaviour:

  • The desktop must transmit only on authorized frequencies.
  • It must control out-of-band emissions.
  • It must share spectrum with neighbours according to coordination agreements.
  • It should have a plan to stop transmitting if commanded.

Good neighbours in orbit do not shout over each other.

What this changes

  • Spectrum is treated as a finite, shared resource requiring ITU coordination and national licensing.
  • The desktop’s communications bands, power, and earth stations must match its licenses.
  • Earth-observing sensors require a remote sensing license and a data policy that accounts for shutter control and sovereignty concerns.
  • Operational licences are as critical as launch licenses.
  • The next entry will cover debris mitigation and export control.