Read the passage below about spacecraft orientation systems. Based on the passage, fill in the blank with the term that logically completes the concluding deduction.
Cevap:Spacecraft utilize electrically driven reaction wheels to adjust their orientation in orbit without expending onboard propellant. As external forces gradually accelerate these wheels, they eventually reach maximum rotational speed, losing the ability to provide further torque. In planetary orbits, operators activate magnetic torque rods to decelerate saturated wheels using the ambient magnetic field. However, when operating in deep space where no ambient magnetic field exists, spacecraft cannot use magnetic rods to desaturate their wheels. Therefore, to regain orientation control after wheel saturation occurs in deep space, a spacecraft must expend onboard 【propellant】.
Cevap
propellant (or fuel)
The passage establishes that reaction wheels manage orientation without expending propellant until they reach maximum speed. In orbit, magnetic torque rods reset the wheels using planetary magnetic fields, but in deep space, no magnetic field is present. Consequently, once magnetic and electrical wheel methods are exhausted, the spacecraft must consume onboard propellant to re-establish orientation control.
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Anahtar Kavram
Drawing logical deductions from synthesized functional constraints