Light · Data · Heat / Orbit to pixel
A planet in view. A signal in the dark.
At 35,786 km above Earth, a geostationary satellite keeps pace with the planet’s turn. A separate civil example, Landsat 9’s TIRS-2, has a focal plane designed for 43 K. Follow infrared light from hot gas through the machinery that turns radiation into information.
Personal educational project based on cited public sources. Not an official publication of my employer or of the agencies or companies discussed. Models are schematic; estimates and assumptions are identified.
As drawn: schematic positions, compressed orbit spacing, enlarged satellites.
Choose your path
Start with a question at each level, inspect a component, then continue inward. Related views return you to where you left off.
01 / The ring
A geostationary satellite follows a circular orbit over the equator in step with Earth’s rotation. It stays above the same point on the ground.
The orbit explains the familiar ring. The spacecraft positions shown here are schematic; this illustration introduces the geometry.
Explore the ringTap a label beside a figure to see the source and the passage behind it.
Open the source register02 / The satellite
The payload observes. The spacecraft supports it with power, communications, and paths for heat to leave.
The infrared payload collects incoming radiation and directs it toward a detector.
Electronics read the detector, process observations, and pass data through communications links.
Thermal paths move heat toward radiators. ABI provides a published example of a radiator releasing instrument energy to space.
Inside the vehicle / A published civil example
GOES-R documents how a spacecraft supplies, points, and cools its instruments. Follow a component below to inspect its role in the representative cutaway.
Battery branch · Charge from available array power; support eclipse and peak demand.
Momentum management · Propulsion also supports attitude and orbital control.
Isolation and blankets · Limit unwanted exchange while preserving the intended rejection path.
03 / The payload
Optics, detectors, electronics and cooler controls work together as one instrument. Start with the assembled hardware, then open its enclosures to see the boards and connections inside.
The drawing connects the telescope to the detector. In the named ABI instrument, the telescope forms a scene image at the focal-plane detectors.
Follow the optical path · Read every payload component
Physical assemblies / ABI civil example
ABI’s Sensor Unit contains the optical train, detector modules and Sensor Unit Electronics. A separate Electronics Unit houses coordinated cards on a common parent board. Cooler-control electronics mount separately to the spacecraft.
A supplier’s responsibility, a physical enclosure and an electrical function describe different boundaries. Lockheed Martin’s 2014 SBIRS release names the prime and payload provider and describes payload delivery for bus integration; it reveals no internal electronics layout.
At integration, mounting, power, commands and timing, science data and thermal interfaces connect the instrument to the spacecraft. NASA describes controlled interfaces and verification throughout design and integration. Explore the assembly and interface map
Functional path / Inside the same instrument
The steps below describe what the electronics does. Readout and conversion belong to sensor-side electronics; packet handling and the spacecraft interface are cards inside the common Electronics Unit.
Instrument controller and clocks coordinate operation.
Cryocooler control closes a separate temperature-feedback loop.
Explore the complete instrument diagrams
The blocks show functional responsibilities; their spacing and the linked cutaway are representative.
04 / The focal plane
At the focal plane, light becomes an electrical signal. Cooling can reduce thermal noise, a benefit described in NIST's cryocooler review.
Supports, electrical connections, and thermal paths meet at the detector assembly. ABI's published design moves heat from its focal planes through the cooler toward loop heat pipes and a radiator. The assembly above remains representative.
05 / The pixel
A semiconductor detector converts absorbed light into an electrical response. Readout electronics measure that response and pass it onward.
The absorber, contact, and readout cell illustrate a sequence. ABI's published component roles provide a named example of photon-to-electrical conversion and electronics reading detector arrays. The drawing does not reproduce an ABI pixel.
06 / The photon
Hot gases emit infrared radiation in characteristic molecular bands. A civil combustion study supplies the band examples here.
Emission at the source and transmission through air are separate questions. Atmospheric gases absorb some wavelengths while transmitting others. This qualitative view supplies no transmission curve or real-system performance.
From pixel to ground
Readout is the beginning of a data path. GAO's description of the Proliferated Warfighter Space Architecture names a spacecraft bus, infrared payload, mission processor, and communications equipment. These are public component roles.
In a separate architecture, GAO's description of the planned FORGE ground system identifies spacecraft operations and mission-data processing. These examples explain responsibilities across architectures; they do not specify a single connected system or a warning timeline.
Follow the ground rolePublished instruments / The civil twins
Weather and Earth-observation instruments let us examine infrared hardware with figures that belong to a named sensor.
ABI observes Earth across visible and infrared channels. This specification belongs to ABI.
TIRS-2 uses a cooled focal plane. This design temperature belongs to the Landsat 9 civil instrument.
The evidence rule
A published specification, an attributed report, a calculation, and an assumption are different kinds of statements. Their labels stay beside the figures.
Each active label opens its source or assumption. Sources that could not be opened remain marked unchecked and support no claim.
Explore the evidenceBehind the project
Reed directs the project, reviews the sources, and chooses the scope. AI coding assistants help build and check it. Blender scripts produce the representative geometry.
This review edition connects the orbit, spacecraft, payload, detector, and emitting gas with ground and civil-instrument side views. Independent orbit and radiation examples show their inputs and formulas. Source, type, and browser checks keep the work reviewable.
Read the method