On-board computer
The On-board computer (OBC) from Orbix designer contains and executes the user flight program of a "space probe". It is the software running on it that determines the sequence in which data from sensors should be collected, how to interpret them, what control commands to issue, when to activate and deactivate the payload (take a picture), and when and what information to transmit to "Earth".
You can read about how to write a simple program for the designer in The First Program section.
Sensors of the spacecraft
Magnetometer
Most often, when designing space vehicles operating in low orbits, one of the orientation determination devices (usually complementing solar sensors) used is the magnetometer.
The magnetometer measures the magnetic field around it, outputting three components of the magnetic field induction vector in units measured in Tesla. Under ideal conditions, the magnetometer on board a spacecraft measures the Earth's geomagnetic field - the one that makes a compass needle turn for terrestrial users. However, in real life, any device's construction contains magnetic materials (for example, permanent magnets in electric drives), so the magnetometer measures a combination of the Earth's field and the spacecraft's field - the so-called field superposition.
Comparing the magnetometer readings with the calculated values of the geomagnetic field model allows the estimation of the orientation (and in some cases, the position) of the spacecraft in space. When conducting experiments with the Orbix designer, it is assumed that the magnetometer will be used as a device for both orientation and position determination of the spacecraft in orbit, i.e., for navigation. The "geomagnetic" field measured by the magnetometer on board is created by a special Terra laboratory set-up and is controlled by a computer according to a pre-defined and known control law.
Angular velocity sensor
The Angular velocity sensor (AVS) allows measuring the current angular rates of the spacecraft along three axes (figure 1). Depending on the sensor's placement, one of these measurements, namely the rotation speed around the thread, will be critically important for controlling the spacecraft, while the other two will help assess the oscillations of its center of mass relative to the local vertical, which can also be used in control.