• Baloon
• Modular
• Multi-purpouse
• Platform
• Sounding balloon
• Standardized
• Yaw-stabilized

Reduction of costs related to space missions and advancements in electronics which have happened in recent years have been reflecting on space industry. Increasing investments are especially directed towards small single satellites or constellations of small satellites orbiting in LEO, which have significantly low cost with respect to larger satellites or other types of space missions. Nevertheless, they require many years of development and large sums on an absolute scale, therefore it is of primary interest the development of new facilities that can cut costs during this phase and offer an higher overall profit margin. One of the main cost item is the development and testing of space hardware, which must be exposed to high-vacuum and high-level-radiation environment, that is both extremely difficult and expensive to recreate in laboratory. A convenient option is the use of near-space platforms lifted by balloons and currently the ones mostly employed are large-scales ones, that is zero-pressure and super-pressure, but even in such cases launch cost is hundreds of thousand of euros. Significantly cheaper options are small-scale sounding balloons, whose launch cost rarely exceeds 1000€, but they are less commonly employed because some instrumentation require a stabilized frame that is not currently a feature offered gondolas for said type of balloons. Applications for platforms with active attitude stabilization are however not limited to space component testings, but they can also compete with LEO satellites, for example in radio occultation and regional monitoring missions, now that technologies for altitude stabilization that can extend the duration of sounding balloon flights are being developed.

The work presented in this thesis shows a successful attempt at designing and realizing a low-cost yaw-stabilized stratospheric platform, that is capable of stabilizing around a set heading direction. Active attitude stabilization was achieved via the use of a single reaction wheel placed along the main vertical axis of the platform, managed by a PI-controller. Tests shows that a stabilized position can be achieved within ±5° of the selected pointing direction, which can be preset or directly inputted by the user during platform operation. Wireless connection between the user and the on-board micro-processor was achieved via the use of a WiFi network. To promote decoupling from roll-pitch motion, passive attitude stabilization techniques were also employed such as the use of guide pieces for suspension ropes, a high quality swivel and control in mass distribution around the rotational axis.

In this thesis, a first application of the platform to host a payload consisting in four solar cells is presented, but particular emphasis was given during design phase so that the integration of a different payload would require the minimum amount of re-design as possible. Therefore, the platform was developed following a modular approach.