Launch of SQUID in portrait Rexus rocket

Short Facts


  • SQUID is a sounding rocket experiment developed at the Royal Institude of Technology in Stockholm Sweden, and is aiming to be part of ESA's REXUS student rocket expierment programme.
  • SQUID stands for Spinning Quad Ionospheric Deployer. The name highlights the main part of the experiment, the deployment of four long wire booms from the spinning probe.
  • The SQUID experiment will be launched on board a sounding rocket from Esrange, the Swedish Space Corporation's space center, outside Kiruna in Northern Sweden.
  • The rockets in the REXUS project are 5.6m long and have a total mass of over 500kg. They can carry a total of three student experiments, one of which can be mounted under the nose cone and ejected near apogee.
  • During launch, the rocket accelerates the experiments for a total of 26 seconds, subjecting them to a maximum acceleration of 20g. After motor burn-out at an altitude of 22km, the speed is great enough to continue carrying the rocket up to its apogee at around 95km. The rocket spins at around 4Hz to stabilize it; the SQUID experiment will continue spinning as it is ejected from the top of the rocket.
  • The SQUID probe is ejected after the rocket has reached high enough to be free of drag from the atmosphere. Right afterwards, it will start deploying its main scientific payload, the four long wire booms.
  • An important part of the project is making sure the wire booms are deployed in such a way that there is no swinging motion once they are fully extended, which would otherwise interfere with the measurements.
  • Metal spheres at the end of the wire booms will become charged by the electric fields of the ionosphere, and it is this data that is of interest in the future scientific application of the experiment design. Understanding of the ionosphere is important for planning satellite programmes, as well as for understanding the aurora and similar "space weather".
  • In future scientific use of the SQUID experiment, multiple probes are to be released from each rocket. This allows for data collection from multiple points in the ionosphere simultaneously, but since simultaneous data downlinking from multiple probes would be complicated, the probe needs to survive landing and be trackable so the recorded data can be found and recovered.
  • Once the booms have been fully deployed and measurements have been taken, they will be retracted before reentry into the atmosphere occurs, at which time temperatures on the surface of the probe can reach 200 degrees C.
  • At an altitude of around 6 km, the top cover the probe will open and a streamer will be deployed. This will pull out a parachute to brake the descent before landing.
  • After landing, the probe will be tracked using GPS signals and a recovery beacon.