Multifunctional structures are more than a new material. The ROV-E proposal has considered the multifunctional design concept as a whole and intends to re-design the future exploration Rovers for Mars (eg ExoMars). The multifunctional approach is applied on several Rovers subsystems: mobility, telecom, power and service module.
In space exploration missions, Rovers have served as a platform for “mobile instrumentation” allowing the achievement of the scientific goals. These goals are very challenging and are more demanding. Due to the increasing need for carrying heavier PL, the mass of the Rovers has increased considerably. The trend is an increase in the total rover’s launch mass.
Therefore, mass is a major issue for interplanetary missions as each additional kilogram influences the cost of the mission and it requires more fuel to be carried (the trajectory is very long). Additionally, the autonomy of rover vehicles is too much dependent on its weight for both propulsion and flexibility on their movements. AURORA programs have identified the possibilities to use lightweight and integrated electronics for moon and mars vehicles.
A need for a light-weight wheeled chassis with a performance comparable to the one provided by the current solutions and which satisfies future scientific needs is a “must” for future surface exploration missions.
The approach proposed on ROV-E is to integrate functions within the carrier structures by using lightweight advanced materials. The re-design of the following subsystems is envisaged: mobility, internal chassis, monitoring, power generation and storage. This re-engineering implies the study of the basic technologies required to improve the performance of each subsystem.
The main objective of the ROV-E project is the development of the technologies required to obtain lightweight–fully integrated equipments and subassemblies for exploration rovers based on multifunctional structures.
On a mission to Mars
Now that the Curiosity Rover of the National Aeronautics and Space Administration (NASA) is settled in on the surface of Mars, taking pictures and gathering samples, the European Space Agency (ESA) is building the next robot it plans to send to probe the mysteries of the 'Red Planet'. An EU-funded project was established to re-design ESA's ExoMars.
Expected to launch in 2018, ExoMars will be tasked to find whether life ever existed or is still active today on Mars. It will host a suite of scientific instruments dedicated to searching for life-related signatures, such as isotopes or molecules that can be interpreted as having been produced by a living organism.
To achieve this, the six-wheeled robotic rover will have the capability to travel up to 70 metres each day searching for signs of past and present life. It will be able to collect and analyse samples from within rocky outcrops and from the sub-surface, down to a depth of 2 metres. The 'Lightweight technologies for exploration rovers' (http://www.rove-project.eu (ROV-E)) project identified the need to reduce the mission cost.
Cutting-edge composite materials will be used to reduce the weight of the rover. However, concentrating solely on reducing the weight of each equipment structure does not lead to further reducing the mass of the overall payload.
The solution that the ROV-E project envisioned was to design shielding, health monitoring, data handling, power generation and other components that integrate multiple functions. It considered revolutionary multifunctional structure (MFS) technology that eliminates chassis, electronic boxes and cabling by integrating electronics, thermal control and structure into a single element.
First proposed in the 1990s, this concept for spacecraft architecture consists of placing the majority of electronics on the load-bearing structure. Printed circuits can also be laminated into the structures' face sheets. This approach, coupled with low-density polymer composites made of high-strength fibres, substantially reduces the overall weight.
Specifically, the first phase of the project was devoted to tailoring thermal, mechanical and electrical properties of composites to fit functionalities added to MFSs. A series of tests on different materials were conducted and a numerical model was developed to calculate mass, volume and energy savings achieved with selected materials.
ROV-E's next phase involved the review of basic design parameters in computer simulations recreating conditions that will be encountered on the Red Planet. Particular emphasis was placed on the mobility sub-systems as the robot will face complex shaped obstacles (rocks), rough terrain with pebbles and sand. Based on the findings, directions for improvement were proposed for all-terrain navigation.
The MFS technology developed is very versatile and can be useful in applications where mass and volume are a concern, as in telecommunications and navigation microsatellites. Just the power storage of the developed MFS can provide up to 2 % savings in the system mass and, ultimately, contribute to reduced fuel consumption and mission cost.