Development of a Solid-State Inflation Balloon Deorbiter

Abstract

In this paper we report on the current development of the Solid State Inflation Balloon (SSIB), a simple, reliable, low-cost, non-propulsive deorbit mechanism for the full range of small satellites (<180kg). Small satellites typically rely on aerodynamic drag to deorbit within the FAA’s 25 year requirements. The SSIB will enhance aerodynamic drag by inflating a balloon at the end-of-life of a satellite mission. This technology will provide a scalable and non-existing capability, low-cost deorbit, for applications in the full-range of smallsats, from CubeSats to MicroSats. The proposed SSIB system is composed of three major components: a Micro-Electro-Mechanical Systems (MEMS) Solid-State Gas Generator (SSGG) chip, a balloon structure made of thin metallized polyimide films such as Kapton® HN composed of multiple lenticular gores which will form a spherical balloon, and a subsystem package suitable for spacecraft integration. The SSGG is composed of a 2D addressable array of Sodium Azide (NaN3) crystals on a glass substrate. The crystals are contained in wells formed by a thick-film of epoxy polymer (SU-8). Under each well is a resistive heater that is selectively addressed using Metal-Insulator-Metal (MIM) diode networks. When heated to above 350 °C, the NaN3 spontaneously decomposes to generate N2 gas in time scales on the order of 10 milliseconds. Each well can be designed with a typical volume of 10−15 m3 to 10−6 m3 of NaN3. The SSIB system has built-in redundancy due to the fact that the SSGG is a scalable chip design and can incorporate as many gas generating wells as a mission may dictate. Additionally, the SSIB can mitigate balloon leaks by sequential deployment of additional gas wells and can thereby maintain the inflated state of the balloon. The SSIB system will be low power (< 1 W) and have low mass (mass is proportional to the size of the required balloon). Initial simulations have shown that the SSIB can deorbit small satellites from above 1000 km within 25 years.