Science Payload

A primary component of the UW Dawgstar nanosatellite design is the science payload to conduct ionospheric measurements. The three ION-F university partner nanosatellites – UW, Utah State University (USU), and Virginia Polytechnic Institute (VT) – would make simultaneous ionospheric measurements for a two-dimensional analysis of spatial and temporal changes in the ionospheric topography. 

The three nanosatellites would be launched together using either the Pegasus launch vehicle or a Space Shuttle mission. Since the launch vehicle selection will be made at a later time, all system components must be designed to accommodate either launch vehicle.

Based on the two proposed launch vehicles' orbit insertion profiles, the UW nanosatellite's orbit will be neither polar nor equatorial. As a result, there will be no opportunity to study geographically specific ionospheric phenomena such as the equatorial anomaly or the polar auroras. It is assumed that the nanosatellite will encounter random ionosphere topography. The proposed nominal altitude of the craft will begin at 375 km. This region of the ionosphere is characterized as F2.

The plasma impedance probe (PIP) being developed by USU is a new instrument which combines previously established technologies by combining them on the same PC board with high-speed circuitry. This instrument would be used to obtain fairly accurate values for electron-neutral species collision frequency, and electron temperature, as well as values of electron density. 

USU indicates that lab testing of the PIP instrument will begin mid-Summer 1999. At that time, more information may become available, and a more detailed integration for the science payload can be designed.

The PIP requires instrument measurements beyond the plasma sheath of the spacecraft. It incorporates two monopole antennas extending 180^o opposite. These booms must deploy from the satellite's body after orbit insertion

Designers at USU are considering two such boom designs. The first design is a "tape measure" type antenna, which unrolls to deploy. The second is a tent-pole tube construction consisting of nested tubes which are extended to deploy.