The PIOneERS experiment is a technological demonstration designed to validate the performance of two space sub-systems, an ionospheric electron density impedance probe, ImP; and a fast-deploying, telescopic boom; Neil. This experiment will be hosted on board a sounding rocket provided as part of the German-Swedish student programme REXUS/BEXUS. The data provided by ImP in the bottom-side ionosphere will be compared to already available data to determine its performance. Once the ImP data will be validated, it will be used to provide in-situ electron density measurements from the top-side ionosphere, from on board other spacecraft hosting it.
ImP will be mounted at the end of a boom sub-system, Neil. This is a boom of 1.75 m in length, thus keeping ImP away from the artificial magnetic field generated by the REXUS rocket body. At this distance, the worst case percentage error in the measurements ranges from 7% at an altitude of 85 km to 16% at an altitude of 75 km. The ImP instrument itself will be making measurements of the upper hybrid resonant frequency of the ionospheric plasma, and by combining those measurements with magnetic field intensity measurements obtained from an inertial measurement unit, the value of the electron density is obtained.
ImP will be transmitting a frequency chirp ranging from 100 kHz to 10 MHz. This will excite the plasma around the probe and induce a current inside the probe. Through the necessary signal conditioning and processing, this current will be converted to voltage and the resonant frequency will be determined. The magnetic field intensity will be measured by a magnetometer as part of an inertial measurement unit (one of two), fitted just underneath the ImP sensor at the end of Neil.
Neil will consist of a telescopic boom made up of several concentric carbon fiber sections that fit inside each other. These will be deployed when the REXUS rocket reaches the desired altitude of slightly less than 75 km, to start the upper hybrid resonant frequency and magnetic field intensity measurements required. Data provided by two inertial measurement units, one placed at the end of Neil and another within the REXUS rocket body will enable the validation of Neil’s performance (i.e. deployment speed, oscillatory behaviour and structural stability) in a micro-gravity environment.
A third sub-system, Mike, is part of the experiment to jettison the Neil and ImP sub-systems just prior to atmospheric re-entry. Pyro-cutters will cut the steel cabling holding the Neil and ImP sub-systems as part of the experiment to ensure that these do not get tangled in the rocket’s parachutes as these deploy. Last but definitely not least, the Buzz sub-system will consist of the experiment electronics and on-board computer, controlling all the different aspects of the experiment and ensuring that the data required form the experiment is recorded and stored onto SD cards on board the experiment.
This test flight will increase the technological readiness level, and also act as a precursor to future orbital flights for both systems.