RESEARCH
Interplanetary CubeSats
The DART group focuses its research to enable autonomous operations of Interplanetary CubeSats. CubeSats are are shoebox-sized spacecraft characterized by a compact and modular LEGO-like structure. Each module, also known as unit, is a cube with edges of 10 cm whose mass is approximately 1.3 kg. This standardized unit is also called 1U. More units can be plugged togheter to create more complex geometry, such as the 12 units (12U) ESA M-Argo CubeSat. Their standardized structure and their reduced size enable to lower the associated manufacturing cost and they ease their deployment at launch.
Traditionally, CubeSats have been launched as secondary payloads of bigger space missions, and their application has been limited to the low-Earth orbit. In recent years, the advances in space technology and research enabled CubeSats to be used for interplanetary exploration. A milestone in this regard was NASA’s MarCO CubeSats (Mars Cube One) which supported InSight landing operations. Given the high benefit in CubeSat use and their reduced costs, ESA financed several interplanetary CubeSat missions to the inner Solar System.
The DART group is strongly involved in the design and operations of the ESA interplentary CubeSats fleet: Milani , LUMIO and M-ARGO.
The research activity of the DART Group focuses on three main areas:
AUTONOMOUS GUIDANCE AND CONTROL
The current paradigm of how space missions are operated imposes that engineers have to frequently communicate with interplanetary spacecraft to update the control actions required to maintain its nominal trajectory. This is a time and resources-consuming process. We are currently working on enabling autonomous guidance and control of deep-space CubeSats, which would allow extremely low-cost interplanetary missions for celestial bodies exploration and exploitation.
AUTONOMOUS NAVIGATION
Navigation is the task of determining the trajectory of the spacecraft. For all interplanetary missions, navigation is currently performed by teams of expert operators, that routinely receive data from the probe in order to determine its position and velocity. This approach increases the cost of the mission and limits the scientific outcome. Our team is working to enable autonomous deep-space navigation, which will employ innovative techniques to allow the spacecraft to reconstruct autonomously its trajectory. This will disrupt the current operational concept of interplanetary probes and will be a key step to democratize deep-space.
TRAJECTORY DESIGN AND OPTIMIZATION
The design of space missions is generally driven by severe requirements on the DeltaV budget. As a consequence, an increased complexity in the trajectory design is needed, ultimately leading to employing high-fidelity models already in the early stages of the design. Flying in highly nonlinear gravity fields allows exploiting unique features, such as libration point orbits, ballistic captures, and low-energy transfers. These features are achieved by exploiting the sensitivity in initial conditions of highly nonlinear environments, and open up new scenarios for spacecraft characterized by very limited thrust authority. However, the dynamics being highly sensitive to initial conditions makes the preliminary trajectory design more challenging, and thus dedicated solutions need to be devised.