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1

2

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z [g

]

0 50 100 150 200 250 300 350 400−2

0

2

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Gyr

o.x

[Hz]

0 50 100 150 200 250 300 350 400−2

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Gyr

o.y

[Hz]

0 50 100 150 200 250 300 350 4000

1

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[Hz]

Preliminary Results From the MUSCAT Experiment Launched on REXUS-13

Marco Tito Bordogna and Emilio Lozano Space and Plasma Physics, Royal Institute of Technology (KTH)

Introduction

The objective of the MUSCAT (MUltiple Spheres for Characterization of Atmospheric Temperature) experiment is to develop a proof of concept of a technique to derive temperature and wind profiles in the stratosphere and mesosphere using active spherical probes.  

Methodology Four free falling units (FFUs) are ejected at an altitude of 58 km. Upon ejection, the FFUs record raw GPS data as they travel through the atmosphere. At 5 km altitude the FFUs deploy parachutes. GPS location is sent to a ground station via VHF link and a satellite modem for a recovery crew to locate and recover the four units. Raw GPS data are then post-processed. From the acceleration profile of the sphere during free fall, it is possible to derive the temperature and the density of the atmosphere.  

Figure 1: The rocket mounted unit (RMU) holds t h e f o u r F F U s u n t i l ejection.  

Result The experiment was launched on the 9th of May at 0600 CET from Esrange onboard REXUS-13 sounding rocket, reaching an apogee of 83 km. FFUs’ ejection, parachute deployment and landing occurred nominally and the probes were recovered within 50 minutes after liftoff.

Conclusion The MUSCAT experiment has proven the engineering functionality of multiple ejectable active falling spheres. Future work includes the analysis of the collected data to derive density, horizontal wind and temperature profiles.

Figure 2: Post processed panorama view of the FFUs ejected from REXUS-13 while it was spinning at 4 Hz.

Figure 4: Drag coefficient of the FFUs for different va lues o f Mach and Reynolds numbers.  

Figure 3: Sensor data of a flight FFU after ejection: Acceleration in z direction and x, y and z component of the angular rate.  

Figure 5: FFU after landing.  

Figure 6: Tracking position of the FFU after parachute deployment. Purple spots are the landing positions.  

Reynolds number [−]

Mac

h nu

mbe

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101 102 103 104 1050

0.5

1

1.5

2

2.5

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1

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2.5