Home▸Space & Astronomy▸Watchdog Timer & Safe-Mode Cascade (2D)

Watchdog Timer & Safe-Mode Cascade (2D)

Interactive 2D spacecraft watchdog-timer simulator: freeze a subsystem's heartbeat on a radial fault diagram, watch its watchdog timer expire and force a reboot, and see repeated resets inside a rolling window cascade the whole spacecraft into Safe Mode.

Space & Astronomy2DModerate60 FPS📱 Mobile-adapted⇄ 3D version

Details

CategorySpace & Astronomy

RenderingCanvas 2D

DifficultyModerate

Target FPS60

ControlsInject Random Fault button (freezes one subsystem's heartbeat); Auto-inject toggle with interval slider (1-15s) for continuous fault injection; Reset Spacecraft button; Watchdog timeout slider (0.5-4s); Safe-Mode reset threshold slider (2-6 resets per 20s window); Simulation speed slider (0.25x-3x); drag the radial diagram to rotate it, scroll/pinch to zoom.

Canvas 2DWatchdog TimerSafe ModeSpacecraft SoftwareFault ToleranceFDIR

Related simulations

FDIR: Autonomous Spacecraft Fault Detection, Isolation & RecoveryA spacecraft too far from Earth for real-time ground control must handle its own failures.…

Radiation Bit-Flip Detector: SEU & Memory ScrubbingCosmic-ray strikes flip bits in a spacecraft's onboard memory as a Poisson process. Watch a…

Spacecraft Autonomous Safing Sequence (2D)Interactive 2D spacecraft safety simulator: inject subsystem faults, watch limit-checking… ⊞ All 1241 in Space & Astronomy →

A spacecraft's software resilience often comes down to a very simple mechanism: every critical task sends a periodic heartbeat, and an independent watchdog timer force-reboots any task that goes silent too long. This 2D radial diagram models four onboard subsystems — attitude control, communications, payload and thermal — each running its own watchdog around a central bus. Inject a fault to freeze a subsystem's heartbeat and watch its watchdog arc drain and force a reboot; trigger enough resets inside a rolling time window (tracked live on the reset-window strip below the diagram) and the mission's fault manager escalates into Safe Mode, shedding every non-essential subsystem and holding only power, thermal and attitude until the vehicle proves stable again. Drag to rotate the diagram, scroll to zoom, and tune the watchdog timeout and Safe-Mode reset threshold to see the trade-off between fast local recovery and cautious mission-level escalation.

⚙ Under the hood

Interactive 2D radial-diagram simulator of a spacecraft's watchdog timers: freeze a subsystem's heartbeat, watch its watchdog arc drain and force a reboot, and see repeated resets inside a rolling 20-second window cascade the whole spacecraft into Safe Mode. Drag to rotate the diagram, scroll to zoom.

Canvas 2DWatchdog TimerSafe ModeSpacecraft SoftwareFault ToleranceFDIR

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install