ALI DEREYURT
2022TÜRKSAT MODEL SATELLITE — CRITICAL DESIGN REVIEW

Model satellite CDR

A full critical design review of a rocket-deployed model satellite: a five-layer modular payload, an actively controlled landing system that holds altitude on PID-driven counter-rotating motors, pyrotechnic smoke capsules for visual tracking, and real-time YOLOv4-tiny object detection on the ground station feed.

TEAM TALIA 4A · TEAM #405365 · FATIH SULTAN MEHMET UNIVERSITY · MARCH 2022 · ROLE: SYSTEM LEAD & OPERATION CONTROL OFFICER

DOWNLOAD THE CDR (PDF)→
FIG 01MISSION PROFILE
700 M400 M200 M150 MGROUND1ASCENTDEPLOY @ 700 M2DESCENTPARACHUTE3SEPARATION@ 200 M · SMOKE4HOVER10 S @ 150 M5RECOVERYMOTORS CUT @ 5 M6LANDINGGPS + BUZZERPARACHUTE — PASSIVE DESCENTSMOKE CAPSULE DEPLOYCARRIER FALLS SEPARATELYTELEMETRY 1–5 HZ + LIVE VIDEO
ASCENT → DESCENT → SEPARATION @200 M → HOVER @150 M → RECOVERY → LANDINGSWIPE →

PRIMARY MISSION

  • Deploy from the rocket at 700 m
  • Autonomous separation at 200 m
  • Active landing on PID-controlled motors
  • Real-time telemetry at 1–5 Hz plus live video

CUSTOM MISSIONS

  • Smoke capsules — colored smoke for visual tracking
  • YOLOv4-tiny object detection on the video feed
  • Hold altitude at 150 m for 10 seconds
  • Dual-channel comms (WiFi + NRF24)
TAB 01SYSTEM BUDGET

<1500 g

TOTAL MASS

5

PAYLOAD LAYERS

20.2 Wh

ENERGY BUDGET

39/39

REQUIREMENTS MET

FIG 02FIVE-LAYER PAYLOAD ARCHITECTURE
ACTIVE LANDING2× 2205 BLDC · COUNTER-ROTATING 4" PROPSL1SEPARATION3-GEAR SERVO · 2× SMOKE CAPSULESL2POWER4S 850 mAh LiPo — 14.28 WhL3ELECTRONICSESP32 · NRF24L01 · MS5611 · MPU9250 · GPS M8NL4CAMERAFOXEER RAZER MINI 1200TVL · DTX03 TX · SDL5PAYLOADSEPARATIONCARRIER (SEPARATES)2S 800 mAh · ESP32 · PARACHUTE
MODULAR STACK — LOW CoG, SERVICEABLE LAYERS, CRASH PROTECTIONSWIPE →

DESIGN GOALS

  • Every layer reachable without disassembling the stack
  • Mass distributed for a low centre of gravity
  • Thermal isolation between the pyrotechnics and the electronics
  • Crash-protection ribs around the PCB layer

MY SCOPE

  • System architecture and the five-layer breakdown
  • Six post-PDR mechanical revisions — FDM printed in PETG/ABS
  • Separation-mechanism gearing and motor mounts
  • Three-phase integration plan; drop, thermal and vibration tests
TAB 02SUBSYSTEM HIGHLIGHTS

ACTIVE LANDING

  • PID gains Kp 15.0 · Ki 0.5 · Kd 8.0
  • Target descent 8–10 m/s; 10 s altitude hold at 150 m
  • Counter-rotating props cancel yaw; gyro corrects drift
  • Motors cut at 5 m, 150 s timeout, battery watchdog

SMOKE CAPSULES

  • 3D-printed double-wall body — thermos-style isolation
  • 60% KNO₃ + 40% sugar, dye and baking soda, 3 g charge
  • ~20 s burn, visible beyond 500 m, exterior stays under 40 °C
  • 10/10 ignitions on an electric fuse at 100 mA

DUAL-CHANNEL COMMS

  • Primary WiFi 2.412 GHz — telemetry and commands, ~1 km
  • Secondary NRF24 2.437 GHz — async 300 KB video pull
  • TL-ANT2424B dish on the ground side
  • 25 MHz channel separation keeps the links from stepping on each other
FIG 03FLIGHT SOFTWARE STATE MACHINE
YERDEYÜKSELİŞDÜŞÜŞAYRILMASABİTKURTARMABİTİŞEEPROM-PERSISTED · SURVIVES POWER LOSS · MANUAL OVERRIDE (KOMUT)
AUTONOMOUS PHASE SEQUENCINGSWIPE →

CRITICAL TRANSITIONS

  • YÜKSELİŞ → DÜŞÜŞ when altitude starts decreasing
  • DÜŞÜŞ → AYRILMA below 200 m
  • SABİT holds for 10 s, then hands back to descent

GROUND STATION & AI

  • C# WPF console: telemetry graphs, GMap.NET GPS map, live video
  • 3D attitude visualisation with HelixToolkit
  • YOLOv4-tiny aircraft detection, ~10 FPS, RarePlanes dataset
  • Pre-flight checklists, mission monitoring, GPS-guided recovery
TAB 03TEAM TALIA 4A

ALI DEREYURT

System lead · mechanical · integration

ABDULLAH SELİM KÖKSAL

Landing control · electrical

ABDUSSAMET KACI

Communication · data processing

NAGKICHAN MOUSTAFA IMPRAM

Flight software · testing

FARUK BERA ZÜLALOĞLU

Ground station · image processing

TEAM MEMBER

Sensors · altitude stabilization

FATIH SULTAN MEHMET UNIVERSITY · TEAM ID 405365 · 28 MARCH 2022