Hall Effect Thruster (HET)

A Hall-effect thruster is a spacecraft propulsion system developed within the scope of electric propulsion technologies, which generates thrust by accelerating ionized gases using an electromagnetic field. In these systems, xenon—a noble gas—is commonly used; after being converted into plasma, it is expelled at high velocity through magnetic field guidance. This process imparts a thrust force on the spacecraft in accordance with Newton’s third law of motion.

History and Development

Research on electric propulsion systems in Türkiye was institutionalized with the “Hall-Effect Thruster Development Infrastructure Project (HALE),” initiated in 2010 and led by TÜBİTAK UZAY.

Through this project, the necessary infrastructure for the design, manufacturing, testing, and integration of indigenous Hall-effect thrusters was established. Additionally, under the leadership of the Türkiye Space Agency (TUA), the HALE project aimed to enhance domestic production capabilities and reduce external dependency in the space sector.

HALE Project

Under the HALE project, the following infrastructure was established at TÜBİTAK UZAY:

Clean room, mechanical and electronic workshops, and work offices (total ~300 m², of which 100 m² is clean room).

Vacuum test facilities:

Tank with diameter 2.3 m × depth 4.5 m (pressure range 2×10⁻⁷ – 13×10⁻⁶ Torr, up to 1.5 kW power).

Tank with diameter 0.6 m × depth 1.1 m (pressure 10⁻⁸ Torr) – for low-power thrusters.

Tank with diameter 1.2 m × depth 2 m – for sub-level testing.

Test equipment: Plasma diagnostic probes (Faraday, Langmuir), magnetic field setups, thermal cameras, flow control devices, vacuum and temperature test chambers.

Automation infrastructure: Sufficient automation for thruster lifetime tests and thermal/cryogenic start-up tests (–150 °C to +125 °C) was commissioned by 2025.

Products and Technical Specifications

The HALE infrastructure includes the following subsystems, primarily centered on two thruster types:

• HALE‑1500 (1.5 kW)
• HALE‑300 (300 W)

In addition, fuel feed units, power processing and control units (PPCU‑1500, PPCU‑300), and fuel tanks have also been developed.

HALE‑1500 Specifications

• Nominal power: 1 500 W
• Thrust: ≥ 70 mN
• Specific impulse: ≥ 1500 s
• Efficacy: ≥ % 45
• Maximum exhaust gas angle: 35° (total 70°)
• Anode voltage: 250–300 V; Anode current: 3–5.5 A
• Mass: 4.5 kg
• Fuel: Xenon, Krypton, Argon

HALE‑300 Specifications

• Power: ≤ 300 W
• Thrust: ≥ 10 mN
• Specific impulse: ≥ 1000 s
• Efficacy: ≥ % 45
• Anode voltage: ~250 V; Anode current: 0.8–1 A
• Mass: ~2 kg
• Fuels: Same

Subcomponents

• Fuel Feed Unit (FFU): 5–150 bar inlet, 2.5 bar outlet, 2.8 kg, 1–5 mg/s flow rate
• Power Processing and Control Unit (PPCU‑1500): 1750 W, 90% efficiency, 16.8 kg
• Fuel tank: Titanium + composite, 150 bar operating pressure, 8.1 l capacity, 4 kg mass

Vacuum Tank (TÜBİTAK)

Technical Operating Principle

In Hall-effect thrusters, a cylindrical plasma chamber is used. A ring-shaped anode is located at the closed end, while the cathode is positioned externally. A high voltage applied between the anode and cathode ionizes the gas (typically xenon).

The magnetic field directs electrons into spiral trajectories, while positive ions are directly accelerated and expelled through the exhaust, thereby generating thrust on the spacecraft. This system is well suited for long-duration and efficient thrust production but is insufficient for launch from Earth’s surface.