On the 19 th October 2016, Schiaparelli, the Entry Demonstrator Module (EDM) of the ESA ExoMars Program entered into the martian atmosphere. Although it did not complete a safe landing on Mars, it transmitted data throughout its descent to the surface, until the loss of signal at 1 minute before the expected touch-down on Mars' surface. The main objective of the Atmospheric Mars Entry and Landing Investigations and Analysis (AMELIA) experiment was the assessment of the atmospheric science and landing site by exploiting the Entry Descent and Landing System (EDLS) sensors of Schiaparelli beyond their designed role of monitoring and evaluating the performance of the EDL technology demonstrator. Although more limited than expected, the flight data received from Schiaparelli are essential to investigate the anomaly that caused the crash landing and for the achievement of the AMELIA scientific objectives. We will present our methodology and results for the reconstruction of the dynamics of the vehicles during the EDL phases from the available flight data in order to assess the trajectory and attitude of the Schiaparelli EDM and to retrieve the atmospheric profiles.
Current electric propulsion technology is based on families of thrusters able to cope efficiently with different mission profiles. However, they are not versatile enough to allow a unique propulsion system technology for the entire mission. Helicon –source-based plasma thrusters promise to bea very versatile family of systems, able to be adaptedto very different mission configurations with a substantial reduction in costs and increase in reliability. However, their development is mainly confined in theUS and Japan. Moreover, although helicon plasma sources have been proved to be very efficient, theirfundamental physical mechanisms need still to be investigated. The Helicon Plasma Hydrazine.Combined Micro (HPH.com) is a research project funded by the European Committee within the 7th Framework Programme of the EU and conducted by an international consortium. Objective of this research is to significantly improve knowledge on helicon-based plasma thrusters through deep numerical/theoretical investigations and extensive experimental campaigns, and then to apply the results to the design, optimization and development of a space plasma thruster. The thruster will be specifically conceived to be used on board a mini-satellite for attitude and position control in order to allow low-cost demonstration mission. Finally, to further increase versatility of this system, far beyond that of a standard electric thruster, a detailed feasibility study will be also conducted to evaluate the possibility of using plasmas to heat and or decompose a secondary propellant, in order to develop a two-mode system, high-efficiency low-thrust plasma-thruster mode and a low-efficiency high-trust secondarypropellant- plasma–enhanced mode. In the following a general overview of the HPH.com research project and a description of the current project status are presented.
The ESA Rosetta spacecraft, currently orbiting around comet 67P, has already provided in situ measurements of the dust grain properties from several instruments, particularly OSIRIS and GIADA. We propose adding value to those measurements by combining them with ground-based observations of the dust tail to monitor the overall, time-dependent dust-production rate and size distribution. To constrain the dust grain properties, we take Rosetta OSIRIS and GIADA results into account, and combine OSIRIS data during the approach phase (from late April to early June 2014) with a large data set of ground-based images that were acquired with the ESO Very Large Telescope (VLT) from February to November 2014. A Monte Carlo dust tail code has been applied to retrieve the dust parameters. Key properties of the grains (density, velocity, and size distribution) were obtained from Rosetta observations: these parameters were used as input of the code to considerably reduce the number of free parameters. In this way, the overall dust mass-loss rate and its dependence on the heliocentric distance could be obtained accurately. The dust parameters derived from the inner coma measurements by OSIRIS and GIADA and from distant imaging using VLT data are consistent, except for the power index of the size-distribution function, which is $α$=--3, instead of $α$=--2, for grains smaller than 1 mm. This is possibly linked to the presence of fluffy aggregates in the coma. The onset of cometary activity occurs at approximately 4.3 au, with a dust production rate of 0.5 kg/s, increasing up to 15 kg/s at 2.9 au. This implies a dust-to-gas mass ratio varying between 3.8 and 6.5 for the best-fit model when combined with water-production rates from the MIRO experiment.
