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| ESA SP-1323: ESA's Report to the 39th COSPAR Meeting |
The 39th meeting of the Committee on Space Research (COSPAR) was held 14-22 July 2012 in Mysore, India.
This report to COSPAR on the scientific activities of the European Space Agency was written by members of the Directorate of Earth Observation, the Directorate of Human Spaceflight and Operations and the Directorate of Science and Robotic Exploration.
Contents:
- Foreword by Jean-Jacques Dordain, Director General, ESA
- Earth Observation
- Introduction
- The Living Planet Programme
- The Earth Explorer Missions
- ERS and Envisat
- Human Spaceflight and Operations
- Introduction
- Overview: Columbus and ISS Facilities
- Funding Europe's ISS Research: ELIPS
- Research on the ISS
- Ongoing Research Using Other Platforms
- Projects under Development
- Science and Robotic Exploration
- Introduction
- Missions in Operation
- Missions in the Post-Operations and Archiving Phases
- Projects under Development
- Missions under Study
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| Publication date: 30 Jun 2012 |
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| Timescales for electron quasi-linear diffusion by parallel and oblique lower-band chorus waves |
| The loss of relativistic electrons from the Earth's radiation belts can be described in terms of the quasi-linear pitch angle diffusion by cyclotron-resonant waves, provided that their frequency spectrum is broad enough. Chorus waves at large wave-normal angles with respect to the magnetic field are often present in CLUSTER and THEMIS measurements in the outer belt at moderate to high latitudes. An approximate analytical formulation of diffusion coefficients has been derived in the low-frequency limit, leading to a simplified analytical expression of diffusion coefficients and lifetimes for energetic trapped electrons. Large values of the wave-normal angles between the Gendrin and resonance angles are shown to induce important increases in diffusion, thereby strongly reducing the particle lifetimes (by almost two orders of magnitude). The analytical diffusion coefficients and lifetimes obtained here are found to be in a good agreement with full numerical calculations based on CLUSTER chorus waves measurements in the outer belt for electron energies ranging from 100 keV to 2 MeV. Such very oblique chorus waves could contribute to a predominantly perpendicular anisotropy of the global equatorial electron population on the dayside and to a relative isotropization at low energy under disturbed conditions. It is also suggested that they might play a significant role in pulsating auroras. |
| Publication date: 30 Jun 2012 |
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| STE-QUEST Payload Definition Document |
| Reference: SRE-PA/2011-075/TN/PW This document describes the Payload of STE-QUEST, a mission in the Fundamental Physics domain conceived to test to high accuracy the different aspects of the Einstein Equivalence Principle. This document derives directly from the STE-QUEST Science Requirements Document and STE-QUEST Mission Requirements Document. It also integrates elements included in the STE-QUEST proposal (and associated reference documents), the STE-QUEST CDF Study and the STE-QUEST Instruments Mid-Term Review datapackages.
This document provides the baseline description of the payload, its instruments, supporting units and interfaces, as defined at the beginning of the STE-QUEST assessment study. It shall be consolidated as part of the study and shall be formally updated at the end of it. This is the first revision of the document, following the completion and closure of the Instruments mid-term Review held in May 2011. |
| Publication date: 22 Jun 2012 |
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| Ion Acceleration at the Earth's Bow Shock |
| Published online 16 June 2012, in Online First The Earth's bow shock is the most studied example of a collisionless shock in the solar system. It is also widely used to model or predict the behaviour at other astrophysical shock systems. Spacecraft observations, theoretical modelling and numerical simulations have led to a detailed understanding of the bow shock structure, the spatial organization of the components making up the shock interaction system, as well as fundamental shock processes such as particle heating and acceleration. In this paper we review the observations of accelerated ions at and upstream of the terrestrial bow shock and discuss the models and theories used to explain them. We describe the global morphology of the quasi-perpendicular and quasi-parallel shock regions and the foreshock. The acceleration processes for field-aligned beams and diffuse ion distribution types are discussed with connection to foreshock morphology and shock structure. The different possible mechanisms for extracting solar wind ions into the acceleration processes are also described. Despite several decades of study, there still remain some unsolved problems concerning ion acceleration at the bow shock, and we summarize these challenges. |
| Publication date: 16 Jun 2012 |
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| Gaia - ESA's Galactic Census |
Cataloguing the night sky is an essential part of astronomy. Before astronomers can investigate a celestial object, they must know where to find it. Without this knowledge, astronomers would wander helplessly in what Galileo once termed a 'dark labyrinth'.
ESA's Gaia mission will create a detailed map of this labyrinth, finding clues to the origin, structure and evolution of our home galaxy, the Milky Way.
Contents:
- The discovery machine
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Stars as individuals and collectives
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Our Solar System and others
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How does Gaia work?
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Building Gaia
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Launch
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The flood of data
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| Publication date: 15 Jun 2012 |
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| Predictive model of magnetosheath plasma flow and its validation against Cluster and THEMIS data |
| An analytical model of magnetosheath plasma flow is described and compared with a large dataset of magnetosheath ion flow velocity measurements from Cluster and THEMIS spacecraft. The model is based on previous works by Kobel and Flückiger (1994) and Génot et al. (2011) and has been modified to overcome the restrictions of these models on the shape of model magnetopause and bow shock. Our model is compatible with any parabolic bow shock model and arbitrary magnetopause model. The model is relatively simple to implement and computationally inexpensive, and its only inputs are upstream solar wind parameters. Comparison with observed data yields a good correspondence: median error in the direction of flow velocity is comparable with the instrumental error, and flow magnitude is predicted with a reasonable accuracy (relative error in flow speed was less than 25% for 86.5% of observations). |
| Publication date: 12 Jun 2012 |
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| The age of the Milky Way inner halo |
| The Milky Way galaxy has several components, such as the bulge, disk and halo. Unravelling the assembly history of these stellar populations is often restricted because of difficulties in measuring accurate ages for low-mass, hydrogen-burning stars. Unlike these progenitors, white dwarf stars, the cinders of stellar evolution, are remarkably simple objects and their fundamental properties can be measured with little ambiguity. Here I report observations of newly formed white dwarf stars in the halo of the Milky Way, and a separate analysis of archival data in the well studied 12.5-billion-year-old globular cluster Messier 4. I measure the mass distribution of the remnant stars and invert the stellar evolution process to develop a mathematical relation that links this final stellar mass to the mass of their immediate progenitors, and therefore to the age of the parent population. By applying this technique to a small sample of four nearby and kinematically confirmed halo white dwarf stars, I calculate the age of local field halo stars to be 11.4 ± 0.7 billion years. The oldest globular clusters formed 13.5 billion years ago. Future observations of newly formed white dwarf stars in the halo could be used to reduce the uncertainty, and to probe relative differences between the formation times of the youngest globular clusters and the inner halo. |
| Publication date: 07 Jun 2012 |
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| On the origin of high-energy particles in the cusp diamagnetic cavity |
| Published online on 1 October 2011.
To appear in a Special Issue of the journal, in press.
We have analyzed Cluster magnetic field and plasma data during a high-altitude cusp crossing in 2003. The Cluster separation was ~5000 km and provided unique measurements of high energy particle properties both inside the DiaMagnetic Cavity (DMC) and surrounding magnetosheath. Most of the high energy electrons and protons had pitch angles of ~90 degrees in the cavity and the high energy particle intensities dropped as a function of distance from the cavity boundary. By assuming conservation of the first adiabatic invariant for the electrons our analysis indicates that most of the high-energy electrons in the diamagnetic cavity cannot directly originate from the magnetosheath or from the magnetosphere. Our test particle simulations in a local 3-D high-resolution MHD cusp model show that particles can gain up to 40 keV and their pitch angles become nearly 90 degrees in the local cusp geometry due to gradients in reconnection 'quasi-potential' agreeing with the Cluster RAPID observations. These results strongly support a local acceleration of particles in the cusp diamagnetic cavities. |
| Publication date: 05 Jun 2012 |
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European Space Agency
Robotic Exploration Technology Plan
Programme of Work (addendum June 2012) |
Addendum to December 2011 Programme of Work 2009-2014.
This document is an addendum to the December 2011 programme of work and includes new activities in the Exploration Technology Programme (ETP, funded by MREP) that are supporting the implementation of ESA's Robotic Exploration Programme from 2009-2014.
This document is provided for information only and is subject to future updates.
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| Publication date: 01 Jun 2012 |
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