1. The ALTEA and ALTEA-Shield experiments onboard the International Space Station
L. Di Fino, M. Larosa, L. Narici, V. Zaconte
University of Rome Tor Vergata

2. Scientific goals
ALTEA (Anomalous Long Term Effects on Astronauts) – PI: Prof. L. Narici
Exposure of crew to space radiation poses one of the most significant hazards to space permanence.
A quest for understanding the risks for the Central Nervous System (CNS) during long permanence in space due to cosmic rays exposure.
Rationale:
anomalous Light Flash perceptions suggest that abnormal (though possibly transient) CNS functional states may result
Theoretically predicted by Tobias: Tobias C.A J. Aviat. Med
First observed in 1969 by Aldrin during Apollo-11 mission
Scientific strategy:
detailed measurement of radiation environment (DOSI)
measurement of transient/long-term functional effects of space environment and cosmic radiation on the CNS (CNSM)
survey of the radiation environment in space habitats (Survey)
test of shielding materials as countermeasures for CNS functional risks (Shield)

3. ALTEA-Space facility Particle Detector (Silicon Detector System)
6 Silicon Detector Units (SDU)
6 silicon planes – 8x16 cm2, 380 mm thick
Geometrical factor
SDU 230 cm2sr
SDS 1180 cm2sr
Detectable LET range: KeV/mm
DOSI – CNSM configurations
EEG, VSU, Pushbutton
DAU
Survey configuration

4. ALTEA facility onboard ISS
Onboard ISS since July 2006
ASI experiment
NASA-SRAG experiment
ESA experiment
> 800 days of acquisition time
> 1 billion triggers

5. ALTEA facility onboard ISS
2006
2007
2008
2009
2010
2011
2012

6. ALTEA configurations DOSI (Dosimetry) ALTEA-Shield Survey
Realtime measurement of radiation flux
Total acquisition time
: 224 days
: 320 days
ALTEA-Shield Survey
Same as DOSI
Different 3D holder
Measurements in 4 different positions
Total acquisition time
: 281 days
CNSM (Central Nervous System Monitoring)
During a 90-minute session the astronaut wears EEG cap, slides under the SDS and signals LF perceptions
: 7 sessions

7. Realtime data
ALTEA data are downloaded and analyzed in realtime at the ALTEA User Home Base (UHB) at University of Rome Tor Vergata.
A subset of ALTEA realtime data is publicly available through the NASA iNTEGRATED SPACE WEATHER ANALYSIS SYSTEM (iSWA) web application.

8. Particle Rate 6 SDUs, triggered particles
pole/equator and orbit precession modulations
increment during passages on the SAA

10. Particle flux and ion abundances
Filter fast particles (ΔE ~ Z2)
Fit with a sum of Landau functions

11. December 2006 Solar Particle Event

12. Integrated Particle Fluxes and LET rates
Integrating Particle flux and LET rate:
X e Y direction: theta e phi ± π/8 intorno all’asse
Z direction: θ < 3/16 * π

13. Particle flux anisotropy
LET rate

14. Conclusions
The ALTEA-Space facility onboard ISS is used since 2006 in different experiments supported by all major space agencies.
It delivered a detailed measurement of the radiation environment inside the UsLab, several measurements on astronauts and a survey of the radiation environment in different positions.
A strong anisotropy (up to a factor 3 in LET) was found when considering high LET particles (LET > 50) coming from different directions.
The second step of ALTEA-Shield (Shield) experiment is planned in 2012 to test the effectiveness of different shielding materials and thicknesses
A collaboration with Jaxa is under consideration for further measurements on astronauts
At last… we are looking for students!

15. Thank you for your attention!