Research activities of the Radio Science and Planetary Exploration Laboratory include: - analysis of radiometric data transmitted by interplanetary probes - radio science experiment requirements definition for future deep-space missions (phase A) - engineering software support to radio science experiments (phases B/C/D). The lab is working on several interplanetary missions, in partnership with space agencies throughout the world: NASA/JPL, ESA, ASI.
The team has been involved since 2001 in the analysis of Doppler data from Cassini, in order to carry out experiments regarding general relativity and gravimetry studies of Saturn and its major rocky moons, including Titan. A significant result has been achieved in the understanding of how numerical errors affect the accuracy of the orbit determination process.
The so-called “Pioneer Anomaly” is an acceleration that causes the Pioneer probes to travel away from the Sun faster than predicted. The work done by the Forlì team suggests that the anomaly can be explained by the anisotropy in the thermal emission of the probe itself rather than by physics phenomena yet to be discovered.
BepiColombo is an ambitious mission to Mercury, expected to achieve range accuracies smaller than 20 cm. In the framework of a partnership with ASI and other universities, the lab is developing a pre-processing routine for the removal of noise signals due to solar plasma and Earth’s atmosphere. Furthermore, the team is involved in the Mercury rotation experiment, based on an optical survey of the planet. The information content of surface pictures will be maximized by choosing the locations to be photographed with a genetic algorithm currently under development. Our lab is also in charge of the definition of a data exchange standard among the agencies involved in the mission, including the programming of reading/writing routines.
The NASA/ASI probe Juno is currently cruising towards Jupiter. The Forlì team will support the gravimetry radio science experiment providing the transmission media noise (plasma and atmospheric) removal algorithm, and by conducting orbit determination analyses.
ESA just selected JUICE (formerly LAPLACE and EJSM, now Jupiter Icy moon Explorer) as its new large-class mission for the Cosmic Vision program, expecting the launch for 2022. The lab is part of the Joint Science Definition Team for this mission.
The lab, as a subcontractor of the DIAA department from University of Rome “la Sapienza” within an ESA tender, participated in the development of a code aimed to determine the angular position of a probe flying through the solar system, by means of a correlation between radio signals transmitted by probes and natural sources and received simultaneously by two separate tracking stations on Earth. The code has been validated successfully by ESA-ESOC’s Flight Dynamics team during the 2005 Venus Express orbit injection maneuver.
Earth’s troposphere contains water vapor, which causes, due to refraction, a path delay in radio waves traveling through the atmosphere. This delay is a noise source that reduce the accuracy of range and Doppler data used for deep-space orbit determination. The team is developing a code that estimates the tropospheric path delay affecting a “rover” GPS receiver (placed nearby the deep-space tracking antenna) by integrating its measurements into a global network of geodetic GNSS receivers (IGS). The same physical quantity can be retrieved by dedicated instruments called Microwave Radiometers: the lab joined a study aimed to the definition of a new generation radiometer capable to achieve high levels of accuracy and temporal stability of the path delay time series.
The Asteroid Impact and Deflection Assessment (AIDA) mission is a project which will demonstrate the kinetic effects of crashing an impactor spacecraft into an asteroid. The mission is intended to test and validate impact models of whether a spacecraft could successfully deflect an asteroid on a collision course with Earth. The project will joint efforts from NASA and ESA. A large US impactor called Double Asteroid Redirection Test (DART) will crash on Didymos B in late 2022 while the Italian cubesat LICIACube will withness the event and observe the immediate effects of the impact. ESA's orbiter, Hera and the two cubesats Juventas and APEX will reach the Didymos system two years later to orbit the asteroid moon and study the crater.
Discover more: ASI LICIACube, HERA