Australian Student Joins the RAIN Sounding Rocket Experiment in Sweden


Australian Student Joins the RAIN Sounding Rocket Experiment to Collect Aerosol Particles in Northern Sweden

William Reid is a Bachelor of Mechatronics and Computer Science student from the University of Melbourne currently on exchange at the Royal Institute of Technology (KTH) in Stockholm, Sweden. In March 2012 he will be part of the team launching a REXUS sounding rocket from Esrange Space Centre in Northern Sweden. On board this rocket will be an experiment called RAIN (Rocket deployed Atmospheric probes conducting Independent measurements in Northern Sweden). The primary scientific objective of the RAIN experiment is to develop a proof of concept of a multi-point aerosol collection technique to find vertical distribution, size and composition profiles in the middle atmosphere.

The launch of an earlier REXUS sounding rocket mission from Esrange Space Centre.

Some of the RAIN team after a long day of experiment testing.

The RAIN experiment has been developed by a group of university students from the Royal Institute of Technology (KTH) and Stockholm University in Stockholm, Sweden. RAIN is part of the REXUS/BEXUS program run by EuroLaunch, a cooperation between the Swedish Space Corporation (SSC) and the German Aerospace Centre (DLR). The team is currently in its final months of preparation, with experiment delivery in mid-November of this year. The team is a diverse group representing seven different countries including Sweden, Russia, Iran, Romania, Germany, China, and even Australia.

The experiment itself is made up of two atmospheric aerosol collectors known as Free Falling Units or FFUs. These collectors take the form of short aluminium cylinders, containing a parachute recovery system, electronics for power, data collection and control and a turntable collection system used to collect aerosol particles.
The three test FFUs without their recovery systems attached. These three will be followed by a further two flight FFUs.

The RAIN experiment’s flight timeline will of course start with the rocket launch. 57 seconds into the flight, at 60 kilometers, the FFUs will be ejected from the rocket and continue to rise to an apogee of 80 kilometers and then begin their respective falls back to Earth. At this stage each of the turntable collection systems will be activated.  A rotating plate will incrementally expose aerosol collection samples via an exposure window in the base of each FFU. By exposing samples in this manner, an aerosol distribution profile of the middle atmosphere will hopefully be found. At 15 kilometers the FFUs will finish their collection plate rotations and seal their precious particle payloads. At 6 kilometers single parachutes on board each FFU will deploy, reducing the FFUs’ fall speeds so that safe landings are ensured. With help from GPS coordinate and radio beacon transmissions from each of the FFUs, a helicopter recovery crew will go out to find them. Upon retrieval of the experiments the RAIN team will observe the exposed aerosol collection samples with a scanning electron microscope.

An FFU during a drop test after the successful deployment of its parachute.

Currently, the RAIN team is engaged in verifying that the experiment functions as it should. Countless tests are being run to prove that the FFUs deploy their parachutes properly, that they transmit their landing locations, that they work in the frigid Lapland winter conditions, that they are ejected from the rocket at the proper speed and orientation, and much more. Given the harsh conditions that the experiment will be exposed to, it is extremely important that the system is tested in similar or even worse conditions beforehand.

More information about the RAIN experiment and the team can be found at The team also regularly posts status updates at the RAIN blog: and the RAIN Facebook page: