Research

Together with “traditional“ approach, in the last years a new concept of planetary surface exploration is being introduced and investigated also within the European Space Agency (ESA). The concept is quite simple and consists in spreading around a certain number of sensors communicating among themselves in a wireless networked fashion. Those sensors, all together, basically constitute a distributed instrument with the potentiality of broadening the capability of making science on and around a planetary body.

In effect, with respect to big and monolithic planetary probes whose new payloads could be able to realize high quality local measurements (i.e. imaging, samples) allow mapping larger planetary surfaces and/or volumes over a large time span. This concept resulting particularly suitable to retrieve localized simple measurements such as pressure, temperature, humidity, gas type, etc that could help supporting the major interest of space exploration, named 1) determine if life never arose on a certain celestial body, 2) characterize the geology and topology of the body surface, 3) characterize its climate and 4) to prepare for human exploration.

In line with this tendency ESA has started project RF-WIPE: RF Wireless for Planetary Exploration project together with the consortium lead by GMV with SUPSI and UPM.
An important aspect of this activity is to identify and characterize possible exploration scenarios suitable to exploit the capabilities of sensors network technologies maximising the scientific return. In addition to this, considering that the existing differences, as well as the possible benefits of using wireless sensor network (WSN) for space exploration is more evident when compared with “traditional” exploration strategies and instruments a certain effort has been dedicated to review the foreseen European and international space missions and the carried payloads.
Within this activity the focus has been limited to planetary surface exploration. Two main categories have been analysed within the RF-WIPE project, with the first one splitting into two different ones:

  • In situ instrumentation and experiment design.

In this case multiple web nodes are spread in or over a large area at the scope of forming a kind of virtual payload able to retrieve planetary data used to map the targeted planetary area. Depending on the environment where the network is deployed, the data can be retrieved from either the surface of the planetary body or from its atmosphere:

  • Surface data retrieval, covering not only the in situ sensing of not easily accessible sites, but also the deployment of a distributed payload for extended coverage and time evolution analysis of the parameters under study.
  • Aerial/atmospheric data retrieval, for the exploration of the atmosphere by deploying the network from an orbiter or other atmospheric element.
  • Support to robotic mean to facilitate surface exploration. In this case the wireless sensors are used both for navigation and localization, and for communication.

RF-Wipe project will design and test in simulation environment and both in laboratory and outdoor a virtual payload able to retrieve planetary data used to map the targeted planetary area. This payload will perform weather characterization by measuring linear evolution of meteorological processes.

Network topology will include linear hoping and multi-hooping in a mesh distribution. For the overall instrument special attention is paid to network robustness, power consumption and deployment mechanism of mote sensors.
Effort is also dedicated to the problem of the web deployment. A simple mechanism will be designed and used within one of the reference scenario.