Search

As the testing and implementation of CubeSat technologies on-orbit becomes more prolific, the need for high-efficiency, low-mass propulsion systems continues to grow. Ionic propulsion systems have emerged as a potential technology to fill the niche of CubeSat propulsion. BeaverCube, a student-built 3U CubeSat from the Massachusetts Institute of Technology, will host an ionic propulsion system demonstration in low Earth orbit. Slated to launch no earlier than October 2020, BeaverCube seeks to demonstrate the Accion Systems Inc. Tiled Ionic Liquid Electrospray propulsion system. This system utilizes an ionic liquidas propellant, giving BeaverCube the ability to make high-efficiency, low-thrust maneuvers. A successful system demonstration will be able to detect a translational maneuver using the NovAtel OEM-719 Global Positioning System receiver onboard BeaverCube. Detectability requires the altitude change of a maneuver to be at least 9 meters, which is 3 standard deviations above the expected GPS altitude error. The goal of this work is to determine the duration of translational maneuver that will result in the highest probability of detection while producing the smallest error in thrust calculation. From simulations performed in Systems Tool Kit, a 3.5 hour maneuver was determined to be optimal, resulting in an altitude change of 280.6 meters.

BeaverCube is a student-built 3U CubeSat that has two main objectives: one science objective and one technology objective. The science goal of BeaverCube is to demonstrate that it is possible to develop and apply platforms that can leverage statistical relationships between temperature and co-varying bio-optical properties, such as light absorption by colored dissolved organic matter. The technology goal of BeaverCube is to demonstrate electrospray propulsion for CubeSats, enabling more coordinated and targeted science missions among multiple spacecraft. The science objective for BeaverCube involves measuring temperature and color, which are key oceanographic properties, through a low-cost platform. Temperature and salinity are used to determine the density of watermasses. This is then used to physically classify them. Thermohaline circulation is a part of large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. Thermohaline circulation plays an important role in supplying heat to the polar regions; it influences the rate of sea ice formation near the poles, which in turn affects other aspects of the climate system, such as the albedo, and thus solar heating, at high latitudes. Small- and meso-scale ocean features such as fronts and eddies canal so be identified and tracked solely using sea surface temperature properties. BeaverCube will track warm core rings on the Northeastern section of the US coast, one of the regions in the world that is heating the fastest due to climate change. Wide geospatial coverage with near-simultaneous measurements of thermal and bio-optical ocean properties by a CubeSat has the potential to address many important oceanographic questions for both basic science and Naval applications. The majority of space-borne optical oceanographic parameters observed from CubeSats rely on atmospheric corrections to provide useful data. BeaverCube will both obtain data and help determine to what extent supplemental data will still be required for atmospheric corrections. BeaverCube will make sea surface and cloud top temperature measurements using three cameras: one visible and two FLIR Boson LWIR cameras. In-situ measurements will be coordinated with an array of ocean buoys to support calibration and validation. The student team successfully tested the LWIR camera on a high-altitude balloon launch in November 2019 to an altitude of 110,000 feet, demonstrating the imaging functionality in a near-space environment. The technology goal for BeaverCube is to demonstrate the operation of the Tiled Ionic Liquid Electrospray (TILE2) propulsion technology from Accion Systems, Inc. for orbital maneuvering. BeaverCube will be deployed in Low Earth Orbit from the International Space Station. The plan is to change the altitude of BeaverCube by 480 meters using 50 micro-Newtons of thrust, detected by an onboard GPS receiver. With a goal of launching in late 2020 or early 2021, BeaverCube passed Critical Design Review in Spring 2020, with subsystems designed and procured, including components from AAC Clyde Space (power), ISIS (ADCS), Near Space Launch (BlackBox with GlobalStar simplex radio and NovAtel GPS), and others (OpenLST radio and Raspberry Pi based C&DH board). Assembly and integration prior to environmental testing are planned for late summer 2020.