Research Fellows, Training and Stagiaires Activities

Please click on the name to expand.
 
John Lyons - Stagiaire from June to September 2009
John Lyons
(Trinity College Dublin)

Calibration of SREM with Neural networks

An investigation into the use of Neural Networks for performing the counts to flux conversion was performed. Neural networks were trained with countrates derived from analystical spectral forms (exponential in energy, power law, AE-8 model). These networks were then evaluated for use as a counts to flux conversion mechanism.

Supervisor(s): H. Evans




Martin Siegl - Stagiaire from February to June 2009
Martin Siegl
(Luleå University of Technology, Dept. Space Science, Kiruna)

SREM - Simulation and Inner Belt Flux Anisotropy Investigation

The work focussed on the PROBA-1/SREM (Standard Radiation Environment Monitor) and the simulation of the instrument's response to the low altitude anisotropic fluxes found in the South Atlantic Anomaly (SAA).

An existing Geant4/GDML model of the SREM was simplified and a set of angular response functions generated using GRAS and the GDML model. These angular response functions were used with flux predictions from the AP-8 radiation belt model and the Badhwar-Konradi anisotropy model to obtain the countrates of the instrument for those models. These results were then compared with flight data.

Simulated results of PROBA-1/SREM response without (above) and with (below) the Badhwar-Konradi anisotropy model.
Simulations of the PROBA-1/SREM using the AP-8 model without (above)
and with (below) the Badhwar-Konradi anisotropy model.



Stagiaire report: ESTEC Working Paper 2360, Aug 2009
Thesis available from LTU: here
Presented at RADECS-2009

Supervisor(s): H. Evans, E. Daly





Alex Hedlund - Stagiaire from June to August 2008
Alex Hedlund
(University of Jyväskylä)

Investigation of SEE effects in memory devices

The work focussed on the "ESA reference SEU monitor", an Atmel memory device conceived as reference for ground testing and in-orbit validation.
  • A review was made of SEU and MBU basic mechanisms in SRAM CMOS memory devices, including diffusion, funnelling, ion track structure.
  • Radiation transport simulations for various shape configurations and charge collection efficiencies were performed with the GEMAT and GRAS Geant4-based tools. The 3-D geometry and response models were successfully validated by comparison to accelerator ground test ion data at several tilt angles.
  • In-orbit predictions were made for the SEU monitor device onboard the Technology Demonstration Payload on AlphaSat.
  • Several upgrades of both the GEMAT and the GRAS tools were instrumental for the achievement of the final results, resulting in a significant improvement of the capabilities of these tools funded by ESA for the space radiation effects community.
Supervisor(s): G. Santin, P.Nieminen





R. Ernst - stagiaire from July 2007
R. Ernst
(University of Aachen),

Subject: Analysis of Hipparcos micro-particle impact data

 

The Hipparcos satellite measured during its operational lifetime several small attitude changes, which are assumed to result from hypervelocity micro-particle impacts. These changes were observed during the Hipparcos attitude reconstruction. Robert will analyse the Hipparcos catalogue with the discrete rate changes and compare the results with our micro-particle flux model predictions.

After this analysis, Robert will use the Hipparcos data to predict the effects of impacting micro-meteoroids for the GAIA mission. This analysis could be used in addition to our (statistical) micro-particle impact risk analysis.

 

Supervisor: G. Drolshagen

 







A.-L. Salagoity - Stagiaire from February to July 2007
A.-L. Salagoity
(Ecole d'ingénieurs MATMECA Bordeaux)

Subject: Design of a Martian wind mill

The first aim of this research is to prove that the Rover of the Martian exploration can work, or at least can be kept in life, thanks to wind power energy. The idea is basically to build a windmill on top of the rover’s roof in addition to the existing solar panels. This windmill could enable to make run the rover when the solar panels are not efficient anymore (during Martian dust storm and during Martian polar night).
The second part of the study is to define, thanks to propeller and blade theories, the more suitable design for this Martian windmill (horizontal or vertical axis, number of blades, blade bank angle, blade radius, blade chord length…).
Once the Martian design defined, similarity method will allow us to calculate the dimensions of an equivalent Earth windmill – a wind mill whose performances on Earth would be equal to a wind mill on Mars. From this calculation, an experimental model of the Earth windmill could be built and performances tests could be conducted.
Anne-Laure used the results of her stage work for her Master thesis.

Supervisor(s): J.-P Huot

 

 





W. Kuiper - Stagiaire from January to June 2006.
W. Kuiper
(Delft University of Technology)

Subject: Verification and application of ESABASE2/DEBRIS impact risk assessment tool

 

Wim performed two main tasks during his stage:

 

First he validated the newly developed software tool ESBASE2/DEBRIS. This PC based tool allows the assessment of the impact risk from meteoroids and space debris objects to spacecraft in orbit. To verify the proper functioning of ESABASE2 Wim established a test plan, wrote several small test programs himself and compared results of ESABASE2 to those from other existing tools where possible. He identified several errors in the code which were subsequently corrected.

 

Next he used the tool to assess the impact risk to future ConeXpress missions. ConeXpress is a planned service spacecraft intended to extend the lifetime of telecommunication spacecraft in the geostationary orbit. The tanks of ConeXpress were identified as being most at risk from hypervelocity impacts. Wim also studied options to enhance the impact protection and calculated that a second protective layer spaced several cm from the tank would greatly reduce the impact risk.

 

Wim used the results of his stage work for his Master thesis.

 

Supervisor(s): G. Drolshagen

 

 





R. Lindberg - YGT from April 2005 to October 2006
R. Lindberg
(Lulea University of Technology)

Subject: Investigation of the effect of radiation transport techniques and tools to space environment engineering margins

 

The work consisted of several activities aimed at the investigation of the uncertainties related to the radiation transport techniques commonly used at the Agency and in Industry for the assessment of the radiation effects to space missions.

 

R. Lindberg made a detailed comparisons of Monte Carlo and Sector Shielding analysis for space applications including:

  • Review of physical interaction models and comparison of radiation transmission probability after shielding
  • Assessment of the radiation transport techniques in simple and complex geometry models, in lightly and heavily shielded systems.
  • Detailed assessment of Total Ionising Dose induced by the space proton and electron environment for a realistic geometry and orbit model, with the ConeXpress mission chosen as example.

 

The results of Ronnie's analyses were published on the refereed journal IEEE Transactions in Nuclear Science.

 

Supervisor(s): G. Santin

 





Felix van der Sommen - Stagiaire from January 2004 to July 2004
Felix van der Sommen
(University Utrecht)

 

Subject: Orbital Evolution of Objects in GEO

 

Felix studied numerically the orbital evolution of uncontrolled objects in the geostationary orbit.

 

He modified and applied an existing tool which was originally developed by ESOC. For his analysis he considered all important perturbing forces: the non-spherical shape of the Earth, the effects from the gravity of the sun and moon and the solar radiation pressure. He studied the long term evolution of objects of different sizes. The area to mass ratio was identified as main parameter which leads to a spread of objects which originate from the same source.

 

Felix also studied the most likely impact velocities and angles of these drifting objects to spacecraft in GEO. His calculations were in perfect agreement with recent optical measurements of drifting objects in GEO.

Felix used the results of his stage work for his Master thesis

 

Supervisor(s): G. Drolshagen

 





R. Lindberg - Stagiaire from September 2003 to April 2004
R. Lindberg
(Lulea University of Technology)

In this work, a model for finding the location of INTEGRAL spacecraft entry into the trapped radiation belts as well as the exit from them was developed using data from the INTEGRAL Radiation Monitor (IREM) instrument. This was done to see if the available science time could be increased by observing possible seasonal variations of the radiation belts as seen by INTEGRAL. Emphasis was on detecting entry in or exit from the outer, electron dominated radiation belt by looking at the count rate of electrons with energy greater than 0.5 MeV.

 

Furthermore, an algorithm was developed to predict the space environment for INTEGRAL in the radiation belts using data from the SREM instrument on the PROBA-1 satellite. The algorithm uses the calculated flux for the two satellites to scale the measured count rate onboard PROBA-1 to a predicted count rate for INTEGRAL.

 

Results from the radiation belt entry and exit model showed a variation over the 13-month period analysed (November 2002 to December 2003). A seasonal variation was detected for the exit points, but similar results for the entry points were difficult to resolve. This was due to INTEGRAL's orbit in which the satellite enters the outer belt in a region where the belt is highly dynamic and variable. The analysis also considered the L-shell, altitude, time from perigee, and local time of the entry and exit points.

 

The results of Ronnie's analyses were used in his Master in Science degree.

 

Supervisor(s): P. Nieminen







L. Rosenqvist - YGT from July 2002 to September 2003.
L. Rosenqvist
(Uppsala Tekniska Högskola)


Subj: Solar proton environment modelling for space missions

 

The work consisted on various activities related to statistical modelling of MeV solar proton fluence for space mission radiation effects assessments. She performed 3 main tasks:

  • review of a solar proton fluence database developed by University of Barcelona of which she found various weaknesses and proposed significant improvements.
  • development of heuristic models to investigate the influence of the dynamics of the solar proton source in the integrated fluence and especially its heliocentric distance gradient.
  • assessment of data processing and quality on the output of solar proton fluence models and development of a procedure for generating model update.

Supervisor(s): A. Hilgers







B. Thiebault - Stagiere from February 2002 to August 2002.
B. Thiebault
(MATMECA, Bordeaux, France)

Subj: Study of a Non-grid aligned inner boundary condition for Poisson equation in PIC codes. Applications to PicUp3D.

 

Supervisor(s): J. Forest







S. Guegan - Stagiaire from June 2000 to September 2000.
S. Guegan
(Ecole MATMECA, Bordeaux, France)

Subj: Preparation of the infrastructure of the Spacecraft Plasma Interaction Network in Europe (SPINE).

 

The training consisted on several items related to the development of SPINE infrastructure. It included: the development of the web site for SPINE, the improvement of the Freja charging database interface, the preliminary work required for the preparation of a proposal for an European training network and a review of the potential of the code PicUp3D as a community simulation tool.

 

Supervisor(s): A. Hilgers







P. Beltrami - Stagiaire from February 2000 to July 2000.
P. Beltrami
(Technical University Braunschweig)

Subj: He performed a very detailed and elaborate meteoroid and space debris impact risk analyses for the Automated Transfer Vehicle (ATV, a resource module for the International Space Station).

 

Using the ESABASE/DEBRIS impact risk assessment tool he studied different options for shielding enhancements of various ATV subsystems and the related mass penalties. He also developed an improved ESABASE model of the Crew Rescue Vehicle (CRV) which can be used for future impact studies

 

Supervisor(s): G. Drolshagen







J. Idestrom - Stagiaire from February 2000 to April 2000.
J. Idestrom
(University of Oldenburg)

Subj: He developed and applied a software tool which calculates the angle between the viewing direction of the GORID impact detector in the geostationary orbit and any fixed user specified direction (e.g. the direction of the sun or of a given meteoroid stream).

 

Supervisor(s): G. Drolshagen







L. Rosenqvist - Stagiaire from June 1999 to August 1999.
L. Rosenqvist
(Uppsala Tekniska Högskola)

Subj: A model of the annual and diurnal variation of the XMM plasma sheet crossing duration was developed. This model improved the long term prediction of the occurrence of background induced in the XMM detectors.

 

Supervisor(s): A. Hilgers







V. Jaffrézic - Stagiaire from June 1999 to September 1999.
V. Jaffrézic
(GMM-INSA, Toulouse, France)

Subj: Long Term prediction of solar proton fluence: scaling based model and comparision with JPL-91.

An investigation of the applicability of the multi-fractal analysis on solar proton fluence time series has been performed.

 

Supervisor(s): A. Hilgers







J.-P. Braeunig Stagiaire from February 1999 to June 1999.
J.-P. Braeunig

Subj: Study of the influence of chlorophyll on the diurnal and annual cycles of the ocean, using a coupled mixed-layer and thermocline model.

 

Supervisor(s): J.-P. Huot







T. Bieler (Stagiaire from University of Aachen) from November 1998 to April 1999.
T. Bieler

Subj: Modelling of impacts from meteoroid streams.

Final report Modelling of Impacts from Meteoroid Streams


Supervisor: G. Drolshagen







N. Crosby - Research Fellow from April 1998 to August 1999.
N. Crosby

Subj: Space weather activities; solar particle event models and predictions.







J. Forest - Stagiaire from March 1998 to July 1998.
J. Forest
(Univ. Versailles St Quentin, DEA Modèles Mathématiques, Simulation et Applications de la Physique)

Subj: Numerical modelling of magnetic interactions on Langmuir probe current in space plasma.

 

Supervisor: A. Hilgers







L. Wedin - Stagiare from June 1998 to December 1998.
L. Wedin
(Uppsala Tekniska Högskola)

Subj: Study and simulation of spacecraft charging in auroral plasma.

 

Supervisor: A. Hilgers







D. Grystad - Stagiaire from April 1997 to July 1997
D. Grystad
(Space Engineering Program of Umeå University, Kiruna)

Subj: Analysis of Meteosat P2 anomaly with the Space Environment Monitor.

 

Supervisor: A. Hilgers







P. Moreno - YGT from April 1997 to April 1998
P. Moreno
(Royal Institute of Technology, Stockholm)

Subj: Installation and testing of Martian Global Circulation Models (GCM).

 

Supervisor: J.-P. Huot







M. Pankhurst - Stagiare from June 1997 to September 1997
M. Pankhurst
(University College London )

Subj: Extending and updating the TEC-EES webpages. Evaluation of the web server usage.

 

Supervisor: E. Daly







U. Svensson - Stagiaire from April 1997 to July 1997.
U. Svensson

(Space Engineering Program of Umeå University, Kiruna)

 

Subj: Simulation of Freja charging events using Polar code.

 

Supervisor: A. Hilgers







S. Tucker - Stagiaire from June 1997 to September 1997
S. Tucker
(University of Bristol, Dept. Aerospace Engineering)

Subj: Analysis of cosmic dust and space debris data obtained from geostationary orbit impact detector (GORID).

 

Supervisor: G. Drolshagen







V. Génot - Stagiaire from March 1996 to July 1996.
V. Génot
(Univ. Versailles St Quentin, DEA Modèles Mathématiques, Simulation et Applications de la Physique)

Subj: Self consistent methods for the computation of non monotoneous electrostatic potential around electron-emitting bodies in space.

 

Supervisor: A. Hilgers






A. Glover - Stagiaire from June 1996 to September 1996 .
A. Glover
(University College, London)

Subj: Analysis of data from the Radiation Environment Monitor instrument and Graphical presentation of dose results for future missions.

 

Supervisor: E. Daly






S. Hamzavi - Stagiaire from Feb 1996 to Aug 1996.
S. Hamzavi
(T.U. Delft, Technical Informatics)

Subj: Langmuir probe measurements reduction using a feed-forward neural network.

 

Supervisor: A. Hilgers






S. Hauptmann - YGT from March 1996 to March 1997.
S. Hauptmann

Subj: Implementation, analysis and enhancement of the 1996 release of the NASA space debris environment reference model, including comparison to existing models and measurement data from retrieved satellite surfaces.

 

Supervisor: G. Drolshagen






A. Zaragoza Gray - Spanish trainee from January 1996 to December 1997.
A. Zaragoza Gray

Subj: (i) Study to include directionality of fluxes of meteoroid streams into ESABASE/DEBRIS; (ii) Hypervelocity impact damage analysis for the Columbus Orbital Facility; (iii) Data processing using IDL and CDF for the Ulysses Data

System; (iv) Radiation analysis using ESABASE/RADIATION for the SREM.

 

Supervisor: G. Drolshagen






J. Bakker - Stagiaire from March 1995 to December 1995
J. Bakker
(Stagiaire from U. Delft, Dept. Aerospace Engineering)

Subj: Cosmic Radiation Induced Interference in Earth-Observation Instrumentation

 

Supervisor: E. Daly






F. Camermans - YGT from March 1995 to March 1996.
F. Camermans

Subj: (i) Visualisation of REM data taken from the STRV-1b satellite; (ii) Extraction of X-ray flux data from the GOES satellite; (iii) Investigation of Meteosat Time-Tagged Anomalies on the Basis of the GOES satellites' Electron Flux Data

 

Supervisor: E. Daly






F. J. López Honrubia - Spanish Trainee from Aug. 1995 to Aug. 1996.
F. J. López Honrubia

Subj.: Non-linear relationship between Meteosat Anomalies and the high-energy electron environment at geostationary orbit using a LVQ neural network.

 

Supervisor: A. Hilgers






P. Nieminen - YGT from April 1994 to April 1995.
P. Nieminen

Subj: (i) Standard Radiation Environment Monitor Detector Design and Simulations; (ii) Simulation of Energetic Particle Effects on the STEP Fundamental Physics Payload; (iii) Electron Induced Fluorescence Flashes and Cerenkov Radiation in the GOME Lens System

 

Supervisor: E. Daly






C.Trenkel - YGT from January 1993 to November 1993.
C.Trenkel

Subj: (i) Comparison of GEANT 3.15 and ITS 3.0 Radiation Transport Codes; (ii) Software Simulation of and Enhanced Radiation Environment Monitor

 

Supervisor: E. Daly






M.Rolfe - Stagiaire
M.Rolfe
(University of Bristol, Dept. Aeronautics and Astronautics)

Subj: (i) O/O+ Ratios for 6 LEO Missions; (ii) Atomic Oxygen Study for Eureca Post-Flight Investigation

 

Supervisor: G. Drolshagen






P. Nieminen - Stagiaire from June 1992 to December 1992
P. Nieminen
(U. Helsinki)

Subj: (i) Lithium-drifted silicon detectors on space radiation measurements: (ii) A study of a compact sensor for space radiation monitoring

 

Supervisor: E. Daly






R. Danner - Stagiaire from February 1992 to August 1992
R. Danner - Stagiaire from February 1992 to August 1992
(Max-Plank-Institut for Extraterresrial Physics)

Subj: Charged-Particle Induced Background Expected on XMM, based on analysis of ISEE particle data and GEANT Monte-Carlo simulation.

 

Supervisor: E. Daly






F. Heck - Stagiaire from November 1991 to March 1992
F. Heck
(U. Karlsruhe)

Observation of Radiation Environment with CRRES Data

 

Supervisor: E. Daly