TRAAC

About This Satellite

TRAAC combined an attitude-control experiment with measurements of neutrons escaping from Earth's atmosphere. Cosmic-ray interactions produce these secondary particles, making them relevant to investigations of the inner radiation belt. The APL instrument measured particle counts, not pictures of Earth or the visible shape of the belt.

Coated and uncoated detectors served different purposes

The payload contained twenty silicon detectors arranged in two groups. Boron-coated units detected charged particles produced by neutron interactions; uncoated units monitored the charged-particle background. Comparing those responses helped distinguish the neutron contribution from other particles capable of triggering the electronics.

The intended two-direction measurement was not achieved

The boom mechanism failed, preventing the planned Earth-facing and outward-facing alignment. Noise also disabled the eight neutron-sensitive detectors on one side. APL nevertheless analysed measurements from the remaining usable package. The authors report that ten-minute pass averages were inadequate and accumulated observations over longer intervals. Its results should not be presented as a fully functioning, directionally stabilized neutron instrument.

Mission reference: Johns Hopkins APL: Williams and Bostrom, The Earth's Albedo Neutron Flux. Editorial review: 2026-09-14.

Motor current was evidence of an attempted deployment, not success

NASA's deployable-boom review reports that TRAAC's extension motor drew stall current for about five minutes without extending the boom. A command and an electrical response therefore did not establish that the mechanical structure reached its intended position. This distinction is important when reconstructing an experiment from telemetry: the actuator can consume power while the hardware remains stuck.

Reference: NASA SP-8065: TRAAC boom extension failure.

The suspected cause remains qualified in the engineering record

The same NASA review attributes the failure to possible payload-fairing damage but explicitly calls the evidence inconclusive. That is a proposed explanation, not a confirmed forensic finding. The documented outcome is the absent boom extension; the more specific claim about what physically obstructed deployment must retain the uncertainty recorded by the engineers.

Reference: NASA SP-8065: uncertainty about the cause of TRAAC mechanical interference.

Reading this orbital snapshot

Based on TLE epoch: 2026-09-05. Estimated altitude ranges from 951 km at perigee to 1,102 km at apogee, a difference of 151 km. The orbital period is about 105.7 minutes. Eccentricity 0.01023 shows why a single altitude cannot describe the whole path. In a two-body approximation, perigee speed is 1.02 times apogee speed. These are mean-element estimates, not instantaneous measurements. Distance per orbit uses an ellipse approximation.

Saved build snapshot. If a valid TLE is retrieved, this explanation and the orbit panel update together. Otherwise this dated snapshot is retained.

Ground track is not sensor coverage

An inclination of 32.44 degrees implies approximate geocentric ground-track limits of 32.4 degrees north and south. This is a prograde orbit, moving in the same general direction as Earth rotation. The plotted line marks the point beneath the object. It does not represent camera coverage, radio reception, or a guaranteed visible pass.

Accuracy and missing information

The introductory record describes the build snapshot. The orbital snapshot explanation and orbit panel share any successfully retrieved TLE; check the displayed epoch. Reentered objects retain historical data only. Mission history is not rewritten by TLE updates. TLE/SGP4 positions are predictions and can change after maneuvers or updated observations. The 14-day stale-data cutoff is a display safeguard, not an accuracy guarantee. Local passes are geometric predictions, not a visibility forecast. No verified operator or mission status means unknown, not active. Do not use this catalog for collision avoidance or operational flight decisions.

Catalog sources: CelesTrak SATCAT: NORAD 205 · GCAT: S00205 (source update 2026 Sep 4 2345:57). Supplementary metadata: SatNOGS DB, retrieved 2026-09-05T12:57:25.375Z. Page assembled 2026-09-15. GCAT phase codes describe trajectory phases, not mission health.

Learn more: TLE data · Perigee and apogee · Ground tracks · JOT (Jewawud Live Orbital Map)

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