Paolo Nespoli, six months out of this world, talks about ALTEA

25 01 2012

From the website www.giovediscienza.org I want to share a public conference during which Paolo Nespoli talks about the period of five months he spent in space onboard the International Space Station. He also describes all the scientific experiments he was involved in during his mission.

At about 12:50 Paolo talks about the ALTEA-Shield experiment he conducted (see ALTEA Shield activity with Paolo Nespoli in 3D and  Paolo Nespoli riattiva l’esperimento italiano ALTEA-Shield, Le immagini della riattivazione di ALTEA on my italian blog). He also describes in the light flash phenomenon:  “This is an experiment because we have a 3D radiation detector that identifies the heavy particles in space which are destroyed or dampened by the atmosphere on Earth, here it doesn’t exist but then here you see that suddenly you feel in space that somebody has taken a photo with a flash and you feel puff!, these are these particles, these are the flashes which take place when one of these radiations go through the eye and through the retina and trigger this reaction”

Enjoy the video!





ALTEA at YRMR 2012 (slides)

23 01 2012

On January 20th I participated to the 3rd Young Researcher Meeting in Rome (read ALTEA at YRMR 2012 (live stream)) with the talk named: "The ALTEA and ALTEA-Shield experiment onboard the International Space Station".

Abstract: Anomalous Long Term Effects in Astronaut’s Central Nervous System (ALTEA) is a helmet-shaped device holding six silicon particle detectors that has been used to measure the effect of the exposure of crewmembers to cosmic radiation on brain activity and visual perception, including astronauts’ perceptions of light flashes behind their eyelids as a result of high-energy radiation. Because of its ability to be operated without a crewmember, it is also being used as a dosimeter to provide quantitative data on high-energy radiation particles passing into the ISS. ALTEA capabilities are also used to give additional information on the exposure of crewmembers to radiation during their stays on ISS for use in health monitoring.
The ALTEA experiment was designed by the Italian Space Agency (ASI) in collaboration with a science team led by Professor L. Narici of Tor Vergata University, Rome. The experiment onboard the International Space Station since July 2006 and it has been used as operative instrument by the Space Radiation Analysis Group (SRAG) of NASA.
Since September 2010 ALTEA detectors are used on a different support for the ESA experiment ALTEA-Shield, which is designed to assess radiation flux in different positions inside the UsLab module. ALTEA-Shield will also provide data about radiation shielding effects by a variety of special materials.
A description of the experiment and a summary of the main results obtained by ALTEA and ALTEA-Shield investigation will be presented.

You can find the slides of the presentation at the following link: (Slides).

If you have any question please feel free to ask with a comment.





ALTEA at YRMR 2012 (live stream)

18 01 2012

The Young Researcher Meeting in Rome is a conference devoted to discussion and interchange of new developments and new ideas in physics. The meeting is primarily aimed at graduate students and postdocs working in physics, who are encouraged to present their work in an informal atmosphere. The main purpose is to create a network of young researchers, both experimentalists and theorists, and fruitful cooperation across the different branches of physics. The meeting is organized in sections, each of them devoted to an active research field in physics: particle and theoretical physics, soft and condensed matter, astrophysics and cosmology, geophysics, biophysics and medical physics, applied physics. Here is the conference program.

ALTEA team will participate with the following talk:“The ALTEA and ALTEA-Shield experiment onboard the International Space Station”

Abstract: Anomalous Long Term Effects in Astronaut’s Central Nervous System (ALTEA) is a helmet-shaped device holding six silicon particle detectors that has been used to measure the effect of the exposure of crewmembers to cosmic radiation on brain activity and visual perception, including astronauts’ perceptions of light flashes behind their eyelids as a result of high-energy radiation. Because of its ability to be operated without a crewmember, it is also being used as a dosimeter to provide quantitative data on high-energy radiation particles passing into the ISS. ALTEA capabilities are also used to give additional information on the exposure of crewmembers to radiation during their stays on ISS for use in health monitoring.
The ALTEA experiment was designed by the Italian Space Agency (ASI) in collaboration with a science team led by Professor L. Narici of Tor Vergata University, Rome. The experiment onboard the International Space Station since July 2006 and it has been used as operative instrument by the Space Radiation Analysis Group (SRAG) of NASA.
Since September 2010 ALTEA detectors are used on a different support for the ESA experiment ALTEA-Shield, which is designed to assess radiation flux in different positions inside the UsLab module. ALTEA-Shield will also provide data about radiation shielding effects by a variety of special materials.
A description of the experiment and a summary of the main results obtained by ALTEA and ALTEA-Shield investigation will be presented.

Follow the 3rd YRMR Meeting in Live Streaming here or on Ustream (http://www.ustream.tv/channel/yrmr-meeting-2012)

The transmission will start on 20 January 2012 at 8.45 until 7.00 pm.

ALTEA presentation will be at 12:20

Send comments and questions if you are registered: the most interesting will be asked to the speakers. For not registered users: you can send questions and comments on the facebook fan page:

http://www.facebook.com/pages/Young-Researchers-Meeting-Rome/275983770232

If you participate and enjoy the presentation, please leave a comment.





Lessons from space

12 01 2012

Expedition 30 crew launched on 22 December from the Baikonur Cosmodrome on a Soyuz spacecraft. The crew is composed by ESA astronaut André Kuipers, Russian cosmonaut Oleg Kononenko and NASA astronaut Don Pettit. They will remain in space for nearly five months as part of the resident, international six-astronaut crew.

During PromISSe long duration mission, André Kuipers will have his eyes on our planet. He will share some of the unique views of Earth from the Station’s Cupola and invite children to become involved in a wide range of educational activities. His observations will support the ESA online lessons designed to help European children strengthen their knowledge in science, technology, engineering and mathematics. These will be part of three themes covering topics such as Life in Space, Biodiversity on Earth and planet Earth’s climate. André will perform experiments on board which can also be carried out by schools. You can follow Andre’s mission here.

Spaceship Earth Theme 1: Life

 

The first lesson of the Life Theme is about radiation. It gives an overview of different types of radiations and how some forms of radiation pose a threat to astronauts. And talking about cosmic ray effects on astronauts a special mention is dedicated to ALTEA. What is ALTEA? What does it do? and What does ALTEA mean for us? are the questions that this lessons does answer.

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You can download this first lesson about radiation here. And of course read all the other lessons. And if you are a student, ask your teachers to download ESA Education kit.

Kit contents:

ISS DVD Lesson 2: Body space
ISS DVD Lesson 3: Space matters
ISS DVD Lessons4: Space robotics
Exploration DVD: The ingredients for Life – on Earth and in Space
Exploration DVD: Feeding our Future – Nutrition on Earth and in Space

Take Your Classroom into Space:
Mass measurement and capillarity
FOAM Stability and Convection
International Space Station Education Kit





Everything you always wanted to know about the International Space Station

11 01 2012

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FREE online from NASA … this tremendously informative, visually captivating, and enriching educational resource: "Reference Guide to the International Space Station — Assembly Complete Edition, November 2010." None really interested of human exploration in space should ever miss this in his personal digital archive. You could learn everything (almost) about your magnificent ISS orbiting at more than 300 Km altitude over your earthly head at 17,500 mph every 90 minutes with multinational humans inside living, working, conducting important science/research experiments, discovering, exploring, and cooperating peacefully. And among the scientific experiments, at page 31, you will find an almost full page dedicated to ALTEA.

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At last a contest: spot ALTEA in a different pic inside the station. Enjoy!





What if you are hit by a cosmic ray?

3 01 2012

Cosmic rays are completely ionized atomic nuclei (without any orbiting electrons) that travel through space at very high speed. We already talked about how they are distributed in LEO orbit (as Space Station and Shuttle orbits) where their intensity increases near the magnetic poles and that there is a trapped component of protons in the inner radiation belt that is crossed by LEO orbits in the South Atlantic Anomaly region.

But what happens when cosmic rays go through matter? Ordinary matter is composed by the same nuclei of the cosmic rays, but in this case the electromagnetic strength binds them to their electrons in order to form atoms. The total charge of electrons is equal and opposite to the charge of the corresponding nucleus in order for the atom to be neutral. The nonintutive fact is that ordinary matter is basically empty. If we look at the simplest atom possible, the hydrogen one, we found a single electron orbiting a single proton (in the classic description): the atom dimension is given by the radius of the electron orbit that is 5.3 * 10-11m, while the nucleus, a proton in this case, has a radius of 10-15m.

To understand the relative dimensions, if you imagine the proton as big as a golf ball (that is about 4 cm) the electron would orbit 1 km far away. The proton mass is 200 times the mass of the electron, so for a 1 kg proton the corresponding electron would weight half a gram. Heavier atoms have slightly different ratios, but the orders of magnitudes are similar.

After this check we are entitled to say that matter is empty and mass is enclosed in a very small space (all in nuclei). So whenever a charged particle (from cosmic rays) crosses matter it has much more probabilities to interact with electron distributions than with nuclei themselves. The particle will lose part of its energy during this interaction and its trajectory will be deflected. These two effects are mainly due to

  • anelastic collisions with atomic electrons
  • elastic collisions with nuclei

Less effective processes are

  • Cherenkov radiation emission 
  • nuclear reactions
  • bremsstrahlung

These interactions happens multiple times during the travelling path and their effect cumulate and cause a total energy loss and deflection. The energy loss by impinging particles is transferred to atoms causing their excitation or ionization. The amount of energy transferred in each collision is a very small fraction of the total kinetic energy of the impinging particle. But the number of collisions is so high that even a small thickness causes a considerable energy loss. A 10 MeV proton loses all its energy in 0.25 mm of copper. The high number of interactions in a macroscopic thickness ends up in reduced statistical fluctuations and it permits to define a mean energy loss for lenght unit, that is called stopping power or dE/dx. In the next post I will talk more about mean energy loss, and we will discover which are more dangerous between low or high energy cosmic rays and why it is so difficult to shield from them.