The design of the tri-axial magnetometer uses Anisotropic Magneto-Resistive (AMR) sensors which are co-located with oset compensating circuitry. The offset compensating circuitry nulls the characteristic offset voltage of the AMR sensor and enhances the sensors performance. The sensor provides x-, y- and z-axes magnetic field component measurements, as well as a sensor temperature measurement which is used for the temperature compensation of the magnetic field measurement. Ideally mounted outside the spacecraft at the end of a rigid boom the NewSpace Systems magnetometer includes low noise, precision processing and analogue-to-digital conversion circuitry; all of which improves the linearity and reduces the drift sensitivity of the sensor head. The integrated processing circuitry and sensor head provide the mission an accurate and stable magnetic field measurement at low power consumption. The power requirement is a regulated 5 V DC supply while the measured x-, y- and z-axes magnetic field components are available as 0-5 V analogue outputs or optionally on a digital serial interface.