G-Chaser student rocket experiment SPID

The G-Chaser student rocket (also called Rocksat-XN) is part of a long series of Rocksat-X student rockets launched by NASA, within the Colorado Space Grant Consortium. It is also part of the Sounding Rocket initiative Grand Challenge led by Prof. Jøran Moen, UiO. This particular rocket, in a series of ten sounding rockets, will be launched from Andøya Space Center in the beginning of January 2019. There are altogether ten student teams on the G-Chaser rocket: one from Japan, two from Norway (UiO and UiT), and the rest from USA.

At UiT, we participate with an experiment called SPID, an acronym for Smoke Particle Impact Detector. This instrument is designed to detect meteoric smoke particles (MSPs) in situ in the winter mesosphere at altitudes between 60 to 80 km.

It is more difficult to detect MSPs in winter than in summer. The reason is that in summer, the mesosphere is very cold and MSPs are embedded within much larger and heavier ice particles, while in winter the mesosphere is warm such that the very small and lightweight dust particles must be detected directly. In situ detection in winter has been tried at a few occasions, but so far without much success.

The big challenge is that as the particles are very light, they are likely to be deflected by the shock front just ahead of the probe. With the SPID experiment, we try to avoid this problem by an open-ended design, so that the air will flow through the instrument with lesser shock front effect and less deflection.

The main goals of this experiment is thus
- using the new probe design (SPID) that will allow detection of small MSPs
- to detect and measure distribution of Meteoric Smoke Particles (MSPs) in the winter mesosphere. 

Figure 1. The probe design is shown in the left drawing. To the right is shown the airflow through and around the probe. The sharp boundary between blue and green regions above the (1/2) probe features is the shock front where higher gas density is formed.

Design, simulation, qualification.

At UiT altogether nine students, one PhD student, two engineers and four supervisors have participated, based at both the Tromsø and Narvik campuses.

First, an ‘Intent to fly’ form was filled and submitted. We then went through several design reviews with Chris Koehler, the Principal Investigator of the Colorado Space Consortium overseeing all the different teams on behalf of NASA.

In these reviews, we had to show that we made progress in defining goals and design, as well as simulations of the instrument and its performance. In addition, plans for the electronics and the control software for the instrument had to be made. On the basis of in particular the latter, we were formally admitted as a team on the rocket.

Building and testing.
The hardware work started beginning of January 2018. Now we had to build and test what we had designed. Electronics controlling biases for the instrument, collection and amplification of the signals were built, and software to control the electronics and collect data for the telemetry was written. In Figure 2 the electronic circuitry is shown.

Figure 2. The final prototype of the control electronics built in Narvik, to be installed in the box (at right).

After the design of the probe was finalized, the probe itself was constructed and assembled. The electronics was mounted together with the probe hardware on a platform we received from NASA. (Figure 3)

 Figure 3. The instrument assembled and mounted on the platform.

Finally all the hardware and software had to be tested. Testing is a crucial part of building an instrument for rockets. You get only one attempt when the rocket is launched. At that time one has to be sure that all parts are thoroughly tested and working correctly!

Testing and integration at Wallops Testing and Flight Facility, Virginaia, USA.

From August 12 – 17 we visited the NASA Wallops Flight Facility to integrate (assemble all the instruments into the body of the rocket) and test our instruments. This experience was the most exciting highlight of the projects so far.  The reports from Wallops along with pictures and movies can be found on Facebook.

Now we are awaiting the launch from Andøya early January 2019.

The Narvik team. From left: Arne Bjørk, James Alexander Cowie, Vetle Tronstad, Erlend Restad, Christer Nordby, and Christoffer Boothby.

The Tromsø team. From left in the back: Tarjei Antonsen, Markus Floer, Ingrid Mann, Ove Havnes, Yngve Eilertsen, and Sveinung Olsen. In front from left: Henriette Trollvik, Åshild Fredriksen, Rikke Hedelund Hansen og Tinna Gunnarsdottir.

September, 2018.
Åshild Fredriksen.