{"id":"orbital-radiation-recovery","level":"infrastructure","name":"Radiation effects, detection and recovery","shortName":"Radiation effects, detection and recovery","role":"Connects mission-specific particle exposure to device behavior and retained workload correctness.","description":"Space radiation can accumulate damage over time or trigger immediate effects from individual particles. Total ionizing dose, displacement damage and single-event effects are different mechanisms and need different tests. A corrected memory error, a reboot, silent corruption and permanent damage also have different operational consequences. NASA’s radiation guidance emphasizes the environment and device response; Suncatcher provides a specific accelerator test example with important limits. Shielding changes exposure but adds mass and does not eliminate every particle mechanism. A useful computing service must detect unacceptable output changes and recover state, not merely keep an accelerator powered after irradiation.","specs":[{"label":"Dose versus event rate","value":"rad(Si) or Gy versus events/time","context":"Accumulated dose is not a count of single-event upsets."},{"label":"Failure classes","value":"Corrected, detected, silent and destructive","context":"Each requires a different mitigation and evidence path."}],"interfaces":[{"name":"Mission radiation environment","direction":"in","signal":"Particle spectrum, shielding and time-dependent exposure"},{"name":"Reliable workload state","direction":"out","signal":"Detected/corrected results or controlled restart"}],"tradeoff":"Shielding and redundancy improve some margins but add mass, power and complexity; error detection also consumes resources and may miss some failures.","whyAI":"Silent corruption can spoil model state without an obvious crash, so application checks and durable recovery matter beyond hardware survival.","related":["orbital-replacement-mass","checkpoint-retained-work","dram-die"],"sources":[{"title":"Space Environments Testbed: What is space radiation?","url":"https://lws-set.gsfc.nasa.gov/space_radiation.html"},{"title":"Towards a future space-based, highly scalable AI infrastructure system design, v2","url":"https://arxiv.org/html/2511.19468v2"}],"scale":"Payload electronics to fleet and lifecycle; conditional scenarios","kind":"architecture","branch":"Frontier infrastructure","subbranch":"Orbital reliability and lifecycle economics","mechanism":["Define orbit, shielding geometry and expected particle environment for the mission.","Test dose accumulation and single-event susceptibility with methods suited to the device and failure mechanism.","Separate memory, logic and host-system responses rather than generalizing from one subsystem.","Apply detection, correction and recovery appropriate to the consequences of each error class.","Scale event expectations and retained-work loss to fleet size while preserving test limitations."],"misconception":"Surviving a total-dose test does not prove immunity to single events or silent data corruption in an entire mission.","check":{"question":"Why must silent corruption be distinguished from a reboot?","options":["It can change results without triggering obvious recovery","It always consumes no energy","It is identical to accumulated dose"],"answer":0,"explanation":"A reboot is visible; undetected wrong state can propagate through a long computation unless higher-level checks catch it."},"science":[{"title":"Simple fleet event expectation","equation":"Nevents = Ndevices λ t","explanation":"λ is events/(device·time), t uses the same time unit and Nevents is expected count.","assumptions":"Independent constant-rate approximation; correlated solar events and heterogeneous devices violate the simplest model."}],"prerequisites":["checkpoint","dram-die"],"learningObjective":"Separate radiation mechanisms, measured test limits and workload-level recovery.","workstream":"W12","visualFamily":"orbital-system","engineeringExample":"Synthetic fleet of 1,000 devices with one relevant event per device-year expects about 1,000 events/year. Even a low individual rate can require substantial monitoring and recovery capacity at scale.","evidenceNotes":"The source test reported HBM irregularities at a lower dose than its maximum single-chip test. Neither threshold is a universal orbital qualification limit.","labId":"library","scope":"Browse the numerical library; no current calculator directly models this lesson’s central mechanism.","labScope":"Browse the numerical library; no current calculator directly models this lesson’s central mechanism."}