Surface Composition of Vesta: Issues and Integrated Approach

The instruments on the Dawn spacecraft are exceptionally well suited to characterize and map the surface composition of Vesta in an integrated manner. These include a framing camera with multispectral capabilities, a high spectral resolution near-infrared imaging spectrometer, and a gamma-ray and neutron spectrometer. Three examples of issues addressed at Vesta are: (1) What is the composition of Vesta??s interior and differentiation state as exposed by the Great South Crater? (2) How has space weathering affected Vesta, both globally and at a local scale? and (3) Are volatiles or hydrated material present on Vesta??s surface? We predict that Dawn finds many surprises, such as an olivine-bearing mantle exposed near the south-pole, a weakly or un-weathered surface that has been relatively recently resurfaced, and a very thin layer of surficial volatiles derived from interaction with the solar wind.     

A systematic spatial bias in remembering eye positions

Categorical bias in location memory in geometric spaces is well established. The present study assessed the presence of the bias in locating eyes in images of human faces. Participants were presented with digital faces and indicated the position of one of the eyes in both upright and inverted orientations. Biases resulted from participants using multiple sources of accessible information. No differences were found for upright vs. inverted face images. Overall, the data were consistent with the retrieval category adjustment model. These distortions may be considered within the forensic context, when eyewitnesses work with a sketch artist or use a computer program to generate an image of the culprit.     

Effects of solar modulation on the cosmic ray positron fraction

We implemented a 2D Monte Carlo model to simulate the solar modulation of galactic cosmic rays. The model is based on the Parker’s transport equation which contains diffusion, convection, particle drift and energy loss. Following the evolution in time of the solar activity, we are able to modulate a local interstellar spectrum (LIS), that we assumed isotropic beyond the termination shock, down to the Earth position inside the heliosphere. In this work we focused our attention to the cosmic ray positron fraction at energy below ∼10 GeV, showing how the particle drift processes could explain different results for AMS-01 and PAMELA. We compare our modulated spectra with observations at Earth, and then make a prediction of the cosmic ray positron fraction for the AMS-02 experiment.     

Vee-tail conceptual design criteria for commercial transport aeroplanes

Vee-tail configuration is an unconventional tail configuration for commercial transport aviation, the use of which could suppose reductions on CO2 emissions. The conceptual design criteria have been selected inspired on the certification requirements established by the aviation regulation in force. They are static stability in cruise, control after Critical Engine Failure(CEF),control in crosswind landing, and trim in these three conditions. The study is carried out through a combination of semi-empirical techniques and Vortex-Lattice Methods(VLM) and thus this analyses the consequences of applying these criteria to a reference aeroplane substituting its conventional tail by a parametrised Vee-tail configuration. The Vee-tail is defined by four parameters:span, root chord, taper ratio and dihedral angle. The results of the study establish a relation between the parameters in order to accomplish the proposed conceptual design criteria. To sum up, minimum and maximum limits are obtained for dihedral angle depending on the combination of the rest of parameters. In addition, a design restriction to the yawing trailing-edge tail control is reached when the results are analysed, demonstrating that its minimum size must be between 60%and 80% of the half-span of the tail, depending on the Vee-tail geometry.     

PANIC – A surface science package for the in situ characterization of a near-Earth asteroid

This paper presents the results of a mission concept study for an autonomous micro-scale surface lander also referred to as PANIC – the Pico Autonomous Near-Earth Asteroid In Situ Characterizer. The lander is based on the shape of a regular tetrahedron with an edge length of 35 cm, has a total mass of approximately 12 kg and utilizes hopping as a locomotion mechanism in microgravity. PANIC houses four scientific instruments in its proposed baseline configuration which enable the in situ characterization of an asteroid. It is carried by an interplanetary probe to its target and released to the surface after rendezvous. Detailed estimates of all critical subsystem parameters were derived to demonstrate the feasibility of this concept. The study illustrates that a small, simple landing element is a viable alternative to complex traditional lander concepts, adding a significant science return to any near-Earth asteroid (NEA) mission while meeting tight mass budget constraints.     

InSight Mars Lander Robotics Instrument Deployment System

The InSight Mars Lander is equipped with an Instrument Deployment System (IDS) and science payload with accompanying auxiliary peripherals mounted on the Lander. The InSight science payload includes a seismometer (SEIS) and Wind and Thermal Shield (WTS), heat flow probe (Heat Flow and Physical Properties Package, HP³) and a precision tracking system (RISE) to measure the size and state of the core, mantle and crust of Mars. The InSight flight system is a close copy of the Mars Phoenix Lander and comprises a Lander, cruise stage, heatshield and backshell. The IDS comprises an Instrument Deployment Arm (IDA), scoop, five finger “claw” grapple, motor controller, arm-mounted Instrument Deployment Camera (IDC), lander-mounted Instrument Context Camera (ICC), and control software. IDS is responsible for the first precision robotic instrument placement and release of SEIS and HP³ on a planetary surface that will enable scientists to perform the first comprehensive surface-based geophysical investigation of Mars’ interior structure. This paper describes the design and operations of the Instrument Deployment Systems (IDS), a critical subsystem of the InSight Mars Lander necessary to achieve the primary scientific goals of the mission including robotic arm geology and physical properties (soil mechanics) investigations at the Landing site. In addition, we present test results of flight IDS Verification and Validation activities including thermal characterization and InSight 2017 Assembly, Test, and Launch Operations (ATLO), Deployment Scenario Test at Lockheed Martin, Denver, where all the flight payloads were successfully deployed with a balloon gravity offload fixture to compensate for Mars to Earth gravity.     

Study of magnetic flux emergence and related activity in active region NOAA 10314

We study the extremely complex active region (AR) NOAA 10314, that was observed from March 13–19, 2003. This AR was the source of several energetic events, among them two major (X class) flares, along a few days. We follow the evolution of this AR since the very first stages of its emergence. From the photospheric evolution of the magnetic polarities observed with SOHO/MDI we infer the morphology of the flux tube that originates the AR. Using a computation technique that combines Local Correlation Tracking with magnetic induction constrains, we compute the rate of magnetic helicity injection at the photosphere during the observed evolution. From our results we conclude that the AR originated by the emergence of a severely deformed magnetic flux tube having a dominantly positive magnetic helicity.     

Inter-satellite links for satellite autonomous integrity monitoring

A new integrity monitoring mechanisms to be implemented on-board on a GNSS taking advantage of inter-satellite links has been introduced. This is based on accurate range and Doppler measurements not affected neither by atmospheric delays nor ground local degradation (multipath and interference). By a linear combination of the Inter-Satellite Links Observables, appropriate observables for both satellite orbits and clock monitoring are obtained and by the proposed algorithms it is possible to reduce the time-to-alarm and the probability of undetected satellite anomalies.