Press Release

Physical and life science experiments “tested” in absence of gravity

By SpaceRef Editor
October 12, 2001
Filed under , ,

On 16 October the Airbus A-300 “Zero-g” will take off from
Bordeaux-Mèrignac airport in France for the first of three parabolic
flights designed to carry out experiments in weightlessness before they
are conducted in real spaceflight.

Parabolic flights are practically the only terrestrial means of
reproducing weightlessness with human operators on board. During a
parabolic flight, the Airbus A-300 “Zero-G” pilot – flying at an altitude
of approximately 6000 metres, usually in a specially reserved air corridor
above the Bay of Biscay – first performs a nose-up manoeuvre to put the
aircraft into a steep climb (to 7600m). This generates an acceleration of
1.8g (1.8 times the acceleration of gravity on the ground) for about 20
seconds. Then the pilot reduces engine thrust to almost zero, injecting
the aircraft into a parabola. The plane continues to climb until it
reaches the apex of the parabola (8500m), when it starts descending. This
descent lasts about 20 seconds, during which the passengers in the cabin
float in the weightlessness resulting from the free fall of the aircraft.
When the angle below the horizontal reaches 45°, the pilot accelerates
again and pulls the aircraft back up to steady horizontal flight. The
manoeuvres are repeated 30 times per flight.

During the 15-19 October parabolic flight campaign, the 31st organised by
ESA, preparations will be made for experiments to be conducted later on a
Russian Foton satellite and on board the International Space Station. The
campaign will focus on physical sciences, life sciences
and biology. Ten experiments proposed by international teams of
investigators, five in physical sciences, three in human physiology and
two in biology, including one from a group of students, will be performed.

In the physical sciences field, one of the experiments is related to fluid
physics, a combustion experiment will study diffusion flames, another
experiment will investigate plasma and the last two will study
interactions of cosmic and atmospheric particle systems in the framework
of an international research programme.

In life sciences, three experiments will measure physiological parameters
in human subjects and two biology experiments will investigate movements
of plants and fish.

All these experiments have been reviewed and selected by peers prior to
flight. A list of the experiments and scientists involved in the 31st
parabolic flight campaign is attached.

The next (32nd) ESA parabolic flight campaign is scheduled for spring 2002
and will have a mixed complement of experiments in life and physical
sciences, including experiments proposed by students.

Further information on ESA parabolic flights can be found on ESA’s special
parabolic flight internet pages at:

http://www.spaceflight.esa.int/users/file.cfm?filename=miss-parafl

For further information:

Vladimir Pletser

ESA/ESTEC

Directorate of Manned Spaceflight and Microgravity

Tel : +31.71.565.3316 (+33.(0)5.56.34.05.99 during the campaign)

Fax: +31.71.565.3141

e-mail : [email protected]

Anna Brueck

ESA/ESTEC

Manned Spaceflight and Microgravity

Tel : + 31.71.565.5445

Fax: + 31.71.565.4499

e-mail : [email protected]

Experiments and scientists involved in the 31st parabolic flight campaign:

1.”Liquid diffusion model experiments in low gravity” by Prof. G.
Frohberg, Dr A. Griesche (Berlin Technical University, D) and Dr G.
Matthiak, Dr R. Willnecker (DLR, Köln, D). This experiment will study
diffusion coefficients of liquids which are difficult to measure on ground
due to other mass transport induced by gravity-caused natural convection.
In microgravity, diffusion experiments are conducted in long capillary
cells and diffusion coefficients can be measured by separating parts of
the cell volume after diffusion took place. The technique of shearing
parts of the cells will be further investigated on different cell designs
to prepare for a space experiment to be flown on the Russian Foton M1 in
Autumn 2002.

2.”Laminar diffusion flames representatives of fires in microgravity
environments”
by Prof. P. Joulain (CNRS, Poitiers, F) and Dr J.L. Torero
(University of Maryland, USA). This experiment will study and characterize
the structure of laminar diffusion flames in microgravity. Diffusion
flames in the absence of natural convection, that removes hot gases from
the combustion site in favor of cold gases, allow to study and better
understand the transport in microgravity of the flame chemical components
by diffusion only. An Ethane flame, subjected to a forced air flow in a
combustion chamber, will be observed by advanced diagnostics techniques,
including CCD visualization, spectroscopy, radiated flow measurements and
thermocouples. The final experiment goal is to provide the scientific
background necessary for the evaluation of material flammability in
microgravity, allowing to reduce the risk of fire on board manned space
vehicles.

3.”Preliminary tests for the International Microgravity Plasma Facility
(IMPF)”
by Prof. G. Morfill, Dr H. Thomas and U. Konopka (Max Planck
Institute, Garching, D). This experiment will investigate the shape and
geometry of newly improved experimental chambers in which a complex
(dusty) plasma, i.e. a mixture of ionized gas and microparticles, is
formed, stimulated by radio-frequency electrodes. New effects were seen
recently on previous microgravity flights, e.g. first, the interaction of
electrostatic Coulomb forces transforming the disordered complex plasma
into an ordered fluid and crystalline phase, a so-called “plasma
crystal”, and second a homogeneous distribution of microparticles in the
plasma. These effects and the impact of the chamber geometry and shape is
further investigated in order to improve the design of the IMPF for a
future flight on the International Space Station.

4.”Tests of an ICAPS facility for ISS” by Prof. J. Blum and Dr T. Poppe
(University of Jena, D). This experiment will study processes of
aggregation of cosmic dust particles, an important step in the formation
of planets in our Solar System. Previous experiments have shown that, in
addition to mechanical and electrostatic effects, magnetic coagulation of
proto-planetesimal dust proceeds rapidly forming aggregates in a few
seconds. In this experiment, magnetized and non-magnetized dust is
injected in turn in an aggregation vacuum chamber by pyrotechnical and
mechanical devices. The dust aggregates are imaged by in-situ microscopy
and collected for later analysis.

5.”Aerosol particle motion in temperature and concentration gradients”, by
Prof. J.C. Legros and Dr A. Vedernikov (University of Brussels, B) and
Prof. F. Prodi (Istituto ISAO-CNR, Bologna, I). This experiment will study
the thermophoretic movements of particles suspended in heated gas, i.e.
the movement caused by the different momentum and energy transferred to
the particles by gas molecules colliding with them from their hot and cold
side. A digital holographic microscope is used a main diagnostic tool,
allowing real-time three dimensional image analysis and tracking of micron
sized aerosol particles. The study of their motion in an aerosol gas gives
information on the nature of chemical reactions taking place at the
surface of the particles, to improve the understanding of the chemistry of
gas-particle systems. These processes are important in several engineering
fields (surface coating, gas cleaning, optical fiber production) and in
atmospheric physics (interaction of atmospheric gases with water droplets
and pollutant particles).

The experiments 4 and 5 prepare for the ICAPS facility to be developed for
long term experiments on board the International Space Station.

6.”Dynamics of prehension in microgravity and its application to robotics
and prosthetics”
by Prof. J.L. Thonnard, Dr O. White (University of
Louvain, B). This experiment will study the hand-eye coordination in
subjects requested to move a hand held load in a rhythmic manner. Previous
parabolic flight studies on the hand prehension dynamics have shown
differences in the strategy adopted by subjects accustomed to microgravity
and naive subjects when requested to perform up and down arm movements
with a hand held mass, or ‘manipulandum’ that measured grip and tangential
finger forces. The present study will focus on the hand-eye coordination
and the visual feedback by varying the arm trajectory and the subject
posture while performing arm movements while holding an improved
‘manipulandum’. These experiments have applications in robotics and
prosthetics where the balance between external forces acting on the object
and the minimal grasping effort is the key to dexterous robotic hand.
Future development could be applied to improve the functional restoration
of humans with handicaps of the upper limbs.

7. “Does weightlessness induce peripheral vasodilatation ?” by Dr P. Norsk
(DAMEC, Copenhagen, DK). This experiment will test the hypothesis of the
dilatation of the heart and the peripheral vascular system that could be
caused by weightlessness, following measurements on human subjects on
ground, during water immersion and during previous ESA parabolic flight
campaigns. According to this hypothesis, the organism may have a
protective mechanism that protect the heart and the brain in microgravity
from an increase of arterial pressure by dilating the vascular system to
cope with the body fluid shift from the lower to the upper part of the
body in 0 g. During the present experiment, the maintenance of arterial
pressure is investigated in several human subjects. Several physiological
parameters are measured, including the cardiac output by the non-invasive
rebreathing method, using a specially designed portable device.

8. “Imaging autonomic regulation during parabolic flight” by Prof. M.
Moser, Dr D.M. Voica (University of Graz, AU) and Prof. A. Noordergraaf
(University of Pennsylvania, USA).This experiment will investigate the
adaptation of the vegetative nervous system before, during and after
parabolic flights. Several sets of physiological parameters are recorded
on human subjects with two portable devices, the Heartman and the Kymo.
First, the heart rate variability (HRV) is recorded by the Heartman and
the HRV structural changes are analyzed by the method of Autonomic
Imaging, specially developed by the Investigators. Second, three other
parameters, the cardio-respiratory coherence (or triggering of breath by
heartbeat), the pulse wave velocity and ballistocardiograms, are recorded
by the Kymo to support the analysis of the data obtained by the Heartman.

9. “Investigation of physiological parameters of gravitaxis in Euglena
gracilis”
by Prof. D.-P. Häder (University of Erlangen-Nuremberg, D). This
experiment will investigate the phenomenon of gravitaxis, the motion away
from the center of gravity. On Earth, without other stimuli, Euglena
gracilis, a fresh water flagellate orients itself upward in the water
column. Some theories claim that gravitaxis is exclusively based on
passive buoyancy effects. The experiment investigates possible
physiological mechanisms in the gravitactic orientation, involving
physico-chemical reactions inside the cells which contribute to the
phenomenon of gravitaxis.

10. “Flying fish” by a group of Students from the University of Lund,
Sweden, has been selected from the group of thirty experiments that flew
in July during the fourth ESA Student campaign organized by ESA’s Outreach
Department. In this experiment several fishes are observed in an aquarium.
Two light sources are located on top and at the bottom of the aquarium.
The behaviour of the fishes in 0g is recorded during several parabolas
with the light coming from the top and during other parabolas with the
light coming from the bottom. It appears that fishes use the light as a
reference in microgravity to orient themselves. The goal of this
investigation is to assess whether an external reference frame given by
light conditions can be used in space to stabilize fish movements and to
allow fishes to have quasi-normal functions during long term space
flights, to be used eventually as a food source for astronauts.

SpaceRef staff editor.