Water Vapor Vertical Profiles on Mars in Dust Storms Observed by TGO/NOMAD

It has been suggested that dust storms efficiently transport water vapor from the near‐surface to the middle atmosphere on Mars. Knowledge of the water vapor vertical profile during dust storms is important to understand water escape. During Martian Year 34, two dust storms occurred on Mars: a global dust storm (June to mid‐September 2018) and a regional storm (January 2019). Here we present water vapor vertical profiles in the periods of the two dust storms (Ls = 162–260° and Ls = 298–345°) from the solar occultation measurements by Nadir and Occultation for Mars Discovery (NOMAD) onboard ExoMars Trace Gas Orbiter (TGO). We show a significant increase of water vapor abundance in the middle atmosphere (40–100 km) during the global dust storm. The water enhancement rapidly occurs following the onset of the storm (Ls~190°) and has a peak at the most active period (Ls~200°). Water vapor reaches very high altitudes (up to 100 km) with a volume mixing ratio of ~50 ppm. The water vapor abundance in the middle atmosphere shows high values consistently at 60°S‐60°N at the growth phase of the dust storm (Ls = 195°–220°), and peaks at latitudes greater than 60°S at the decay phase (Ls = 220°–260°). This is explained by the seasonal change of meridional circulation: from equinoctial Hadley circulation (two cells) to the solstitial one (a single pole‐to‐pole cell). We also find a conspicuous increase of water vapor density in the middle atmosphere at the period of the regional dust storm (Ls = 322–327°), in particular at latitudes greater than 60°S

Design, Manufacturing, and Test of a Real-Time, Three-Axis Magnetic Field Simulator

This paper deals with the design, manufacturing, and test of a three-axis magnetic field simulator for space applications. The main aim of this simulator is to reproduce the orbital magnetic field conditions in a definite volume. The simulator makes it possible to carry out the ground calibration campaign of the satellite magnetic sensors and can be used in attitude control system simulations that exploit “hardware in the loop” devices. An overview of the mechanical and electronics design of the system is given; the mathematical model of the expected field is also discussed, achieving design constraints to get the largest homogeneous magnetic field volume. Moreover, test campaign results regarding magnetic field homogeneity are depicted and compared with those expected in theory

Plastic Cubesat: An innovative and low-cost way to perform applied space research and hands-on education

This paper describes the design and the manufacturing of a Cubesat platform based on a plastic structure. The Cubesat structure has been realized in plastic material (ABS) using a rapid prototyping technique. The rapid prototyping technique has several advantages including fast implementation, accuracy in manufacturing small parts and low cost. Moreover, concerning the construction of a small satellite, this technique is very useful thanks to the accuracy achievable in details, which are sometimes difficult and expensive to realize with the use of tools machine. The structure must be able to withstand the launch loads. For this reason, several simulations using an FEM simulation and an intensive vibration test campaign have been performed in the system development and test phase. To demonstrate that this structure is suitable for hosting a complete satellite system, offering innovative integrated solutions, other subsystems have been developed and assembled. Despite its small size, this single unit (1U) Cubesat has a system for active attitude control, a redundant telecommunication system, a payload camera and a photovoltaic system based on high efficiency solar cells. The developed communication subsystem has small dimensions, low power consumption and low cost. An example of the innovations introduced is the antenna system, which has been manufactured inside the ABS structure. The communication protocol which has been implemented, the AX.25 protocol, is mainly used by radio amateurs. The communication system has the capability to transmit both telemetry and data from the payload, in this case a microcamera. The attitude control subsystem is based on an active magnetic system with magnetorquers for detumbling and momentum dumping and three reaction wheels for fine control. It has a total dimension of about 50 750 750 mm. A microcontroller implements the detumbling control law autonomously taking data from integrated magnetometers and executes pointing maneuvers on the basis of commands received in real time from ground. The subsystems developed for this Cubesat have also been designed to be scaled up for larger satellites such as 2U or 3U Cubesats. The additional volume can be used for more complex payloads. Thus the satellite can be used as a low cost platform for companies, institutions or universities to test components in space

Inflatable system based on polyurethanic foam

REDEMPTION experiment for Rexus / Bexus programme allowed to test several solutions to use a particular foam. This substance is a bi-component poliuretanic foam which expands and becomes rigid. Thanks to REDEMPTION it has been possible to test this foam in near space conditions. One of the tests of REDEMPTION experiment was to use this foam like a inflatable rigid structure to deploy a boom. This test was a success also during ground test. This kind of boom can be deployed in a couple of seconds and thanks to a particular property of the foam can be bigger in volume than the two substances boarded on the space system. This boom could also supply a structure with good mechanical properties. Is a project completely conceived, designed and realised within the Space Robotic Laboratory (SRL) of the II Faculty of Engineering of the University of Bologna "ALMA MATER STUDIORUM", based on REDEMPTION (REmoval of DEbris using Material with Phase Transition: IONospherical tests) experiment has been selected to participate to REXUS/BEXUS 2012 Programme. REDEMPTION allowed to test several solutions to use a particular foam. This substance is a bi-component poliuretanic foam which expands and becomes rigid. The paper describes the IBS inflatable system's characteristics, the mission's configuration, concept, design, process, mechanical assembling and the expected results.©2012 by the International Astronautical Federation

Euclid: Testing the Copernican principle with next-generation surveys

The Copernican principle, the notion that we are not at a special location in the Universe, is one of the cornerstones of modern cosmology and its violation would invalidate the Friedmann-Lemaître-Robertson-Walker (FLRW) metric, causing a major change in our understanding of the Universe. Thus, it is of fundamental importance to perform observational tests of this principle. We determine the precision with which future surveys will be able to test the Copernican principle and their ability to detect any possible violations. We forecast constraints on the inhomogeneous Lemaître-Tolman-Bondi model with a cosmological constant $\Lambda$ ($\Lambda$LTB), basically a cosmological constant $\Lambda$ and cold dark matter ($\Lambda$CDM) model, but endowed with a spherical inhomogeneity. We consider combinations of currently available data and simulated Euclid data, together with external data products, based on both $\Lambda$CDM and $\Lambda$LTB fiducial models. These constraints are compared to the expectations from the Copernican principle. When considering the $\Lambda$CDM fiducial model, we find that Euclid data, in combination with other current and forthcoming surveys, will improve the constraints on the Copernican principle by about $30\%$, with $\pm10\%$ variations depending on the observables and scales considered. On the other hand, when considering a $\Lambda$LTB fiducial model, we find that future Euclid data, combined with other current and forthcoming data sets, will be able to detect Gpc-scale inhomogeneities of contrast $-0.1$. Next-generation surveys, such as Euclid, will thoroughly test homogeneity at large scales, tightening the constraints on possible violations of the Copernican principle