D-Sat is a three-unit CubeSat designed, built, and operated by D-Orbit. It will be launched into a 500 km sun-synchronous orbit.
D-Sat was launched on June 23rd, 2017 with the goal to validate our solid propellant motor in Space.
Moreover, as we also wanted to make sure that this mission would harness the full potential and opportunities granted by sending a satellite to space, we partnered with several institutions to include three experiments that will be performed throughout the mission’s lifetime. In tune with our philosophy, all three experiments have a social impact.
To understand the importance of this mission, first we need to address the problem that makes it relevant: space debris.
The problem: space debris
Our world is increasingly dependent on space-based assets for applications like Earth observation, weather forecast, global navigation, disaster prevention, high-precision farming, and self-driving cars.
This technological progress is leaving Earth’s orbit crowded by an increasing population of man-made objects that no longer serve a useful purpose, like nonfunctioning satellites, rocket’s upper stages, and other objects released during a space mission. A collision between two larger pieces of debris and the explosion of rocket bodies are the kind of events that can create further smaller debris. According to NASA, there are hundreds of thousands of pieces of debris ranging in size between 1 cm (0,4 inches) and 10 cm (4 inches) traveling around Earth, and this number is likely to increase if we keep leaving nonfunctioning satellites in orbit.
OUR SOLUTION: SElf-decommissioning satellites
While there is not much we can do for space junk that is already in orbit, we realized that things could quickly improve by following a simple principle: everything that goes up must come down as soon as it is not useful.
To make this possible we imagined a device with three key characteristics. First of all, it needed to be compact and lightweight, easy to integrate it inside existing satellite platforms during design and manufacturing. Second, it had to be able to execute a precise direct re-entry maneuver at the end of the satellite’s mission. Finally, it had to be independent from the main spacecraft’s systems, so it would work even in case of major malfunction of the hosting satellite.
After months on the drawing board, we came up with D-Orbit Decommissioning Device (D3), a smart propulsive system that can be scaled to easily fit any size spacecraft. Its compact solid rocket motor is designed to execute a high-trust burn to quickly remove a spacecraft form orbit. Its independent control unit and communication system ensures that the system can be activated and controlled from the ground even if the spacecraft has ceased operations.
Other than technology validation, the other main goal of the D-Sat mission is scientific investigation.
In fact, throughout its mission D-Sat will perform three experiments: SatAlert, Debris Collision Alerting System (DeCas), and Atmosphere Analyzer.
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SatAlert, designed in collaboration with the National Inter-University Consortium for Telecommunications (CNIT), University of Florence Research Unit, is an in-orbit validation of the Multiple Alert Message Encapsulation (MAMES) protocol, defined by ETSI (European Telecommunications Standards Institute). MAMES is an extensible multiple alert message encapsulation protocol for transporting alert messages of different formats over satellite links. It guarantees the timely distribution of alert messages to the people affected by critical situations in context with limited network coverage.
During the experiment D-Sat will collect MAMES emergency messages sent from a ground station, store them onboard, and re-broadcast them to national public safety entities upon receiving a trigger command. This experiment will validate a typical emergency scenario where civil defense agencies need a means to broadcast instructions in areas affected by natural disasters when the ground telecommunication infrastructures have been damaged.
DeCAS (Debris Collision Alerting System), developed by Aviosonic Space Tech, is a patented system able to determine the dynamics of the debris footprint area associated to the re-entry of the hosting satellite During re-entry, DeCAS activates itself, determines its own position and broadcasts its location and the debris footprint dynamics forecast to civil protection agencies. In a real-world scenario, this information would be processed on ground and then transmitted in real-time to airplanes flying over that zone through the Air Traffic Control Center, and to the populated areas below through national public safety agencies.
During the in-orbit validation phase, the forecast of D-SAT simulated re-entry footprint will be encapsulated inside MAMES messages that will be transmitted to Aviosonic’s ground station at Andrea Ponti Institute in Gallarate, Italy, validating all the DeCAS communication phases and the three segment DeCAS system (space, ground, and user).
During re-entry phase, DeCAS will perform a final test in operational conditions, demonstrating the viability of the technology.
Atmosphere Analyzer is a data collection experiment aimed at collecting in-situ atmospheric data from the lower ionosphere during the re-entry maneuver. Before breaking up, D-Sat will cross the region between 80 km and 150 km. This is the least studied region of the atmosphere because it can’t be reached by satellites or stratospheric balloons. By doing so, D-SAT will validate an innovative approach for an in-situ data collection system that will be further developed in a dedicated mission in 2019.
These emergency scenarios are becoming increasingly common, given the tight correlation between climate change and extreme weather conditions like hurricanes, wildfires, tornadoes, extreme rainfalls, and floods, and for this reason SatAlert may help saving thousands of lives.