DEvice for the study of Critical LIquids and Crystallization - Alice Like Insert-Refurbishment (DECLIC ALI-R) - 03.07.18

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
DEvice for the study of Critical LIquids and Crystallization Alice Like Insert-Refurbishment (DECLIC-ALI-R) studies liquids at the verge of boiling. The flow of heat during boiling events is different in microgravity than it is on Earth. Understanding how heat flows in fluids at the verge of boiling helps scientists to develop cooling systems for use in microgravity.
Science Results for Everyone
Information Pending

The following content was provided by Gabriel Pont, and is maintained in a database by the ISS Program Science Office.
Experiment Details


Principal Investigator(s)
S├ębastien Rouquette, Ph.D., Centre National d'Etudes Spatiales, 31400 Toulouse Cedex 4, France

Burger Herve, M.S., Centre National d'Etudes Spatiales, Toulouse, France

Information Pending

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
NASA Research Office - Space Life and Physical Sciences (NASA Research-SLPS)

Research Benefits
Earth Benefits, Scientific Discovery

ISS Expedition Duration
April 2017 - August 2018

Expeditions Assigned

Previous Missions
DECLIC-ALI-R is a continuation of the DECLIC-ALI experiment and an experiment conducted aboard the Mir Space Station and the Space Shuttle.

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Experiment Description

Research Overview

  • Any fluid can be characterized by a temperature and a pressure that defines its critical point, beyond which the gas and the liquid can no longer be distinguished (the two phases coexist in a critical phase).
  • DEvice for the study of Critical LIquids and Crystallization Alice Like Insert-Refurbishment (DECLIC-ALI-R) DECLIC-ALI-R studies how heat flows in liquids which are just below the critical point in microgravity.
  • This experiment uses a thermostat to measure heat in certain liquids just below the critical point.
  • This investigation is important for the development of cooling systems for use in space as well as systems which may be useful in waste disposal and recycling on earth.


DEvice for the study of Critical LIquids and Crystallization Alice Like Insert-Refurbishment (DECLIC-ALI-R) studies the transformation of fluids from the state of liquid/vapor coexistence to the supercritical single phase state. The objective of the ALI study is to use the DECLIC facility in the ISS to study a variety of equilibrium and non-equilibrium phenomena using such near-critical fluids. These phenomena have in common the study of new, unexplored behavior of near critical fluids from which several breakthroughs can be expected.
ALI is intended to study near-ambient critical fluids (SF6 in first increments and possibly carbon dioxide (CO2) in future increments) and is installed in the Experiment Locker (EXL) of the DECLIC instrument. It provides the environment (set temperature in the range 30°C to 52°C-) and stimuli for the 2 cells containing samples under study. One cell is used for direct observation, the other for interferometric (pertaining to the science of combining two or more waves) observation. The mechanical part accommodating the two fluid cells is called SCU (Sample Cell Unit).
These two experimental fluid cells housed in the SCU have a temperature that is monitored by a very accurate thermal regulation of the DECLIC facility. All the high-resolution and high-speed optical diagnostics are synchronized with in situ temperature and pressure measurements. The cells are adjusted to the selected monitoring rate of the thermal stimuli produced by the two heaters (thin resistive transparent layer or massive fluxmeter [instrument that measures the change of flow]).
The main objective of the ALI-R (refurbishment) is to replace the direct observation cell by an identical cell filled with SF6, as close as possible to the critical density. To do so, ten new cells are being manufactures and integrated. These are filled and tested on the ground, and the best (i.e. SF6 density closest to the critical density) are selected and integrated in the ALI insert.
The ALI-R measures experimentally the effects of the non-zero value of the Green-Fisher exponent in the liquid-gas critical point for the first time. By analyzing the theoretical predictions, a measurement of the turbidity of the SF6 sample with a precision better than 0.3% near the critical temperature (~1mK above the Tc) in microgravity condition could test the theoretical predictions. In order to achieve this goal, a new sample cell has to be prepared such that the average density is closer to the critical density (< 0.1%) than the current ALI-R sample cell.

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Space Applications
The knowledge gained enhances understanding of the behavior of cryogenic (very low temperature) rocket propellants especially the dynamics regarding near-ambient temperature critical fluids. DECLIC is designed for telescience from the ground, and it offers scientists the capability to remotely control experiment conditions onboard the ISS provided by DECLIC lockers.

Earth Applications
The use of near-critical fluids allows important parameters such as compressibility of supercritical fluids, density of gas and liquid phases, and surface tension to be manipulated in a scalable way by using small changes in temperature. The readily variable properties of near-critical fluids make them appealing candidates for studying numerous interesting phenomena valid for all fluids, which can ultimately lead to the development of improved chemical solvents which also could be less harmful to the environment.

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Operational Requirements and Protocols

The DECLIC-ALI-R Experiment is scheduled over a period of 74 days. DECLIC-ALI-R requires the collection of both temperature and pressure measurements. The DECLIC-ALI-R operation consists of a number of thermal cycles under various diagnostics. The first 2 cells, filled with SF6, are studied simultaneously in the same insert during approximately a 2-month period of experiment running time. The status of the ongoing experiment is reported to the ground via telemetry. The experiment survey by the crew is limited to occasionally checking the front panel LEDs. In case of alarm (red LED), the crew may report to ground and wait for instructions (either leave as is; ground initiates recovery of experiment; or it can be switched off to end the experiment).

The ISS crew installs the DECLIC hardware into an EXPRESS Rack in the U.S. Laboratory. After the first insert (ALI) is installed into DECLIC, the facility must be powered on to begin commissioning. The commissioning goes through a sequence of steps initiated from the ground to check the hardware integrity and software functions. Once commissioning is complete, the run is started. Crew participation is not required during the runs. The ALI-R insert is installed into DECLIC for the first run of the DECLIC-ALI-R series of experiments (74 days). Tape change-out by the crew is required at selected stages in the run(s).

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Decadal Survey Recommendations

Applied Physical Science in Space AP5
Fundamental Physical Sciences in Space FP4

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Results/More Information

Information Pending

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Related Websites
DECLIC: French experiment on ISS reveals new insights -

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The ALI is a thermostat for critical fluid experiments between 30 and 65 degrees Celsius. The thermostat is an adapted ALICE-II design. The top part of the insert consists of the so-called electronic box. This box has three printed circuit boards (PCBs) one for the temperature control, one for the power distribution and one for the sensor acquisition and actuator commanding of the science experiment. Image courtesy of CNES.

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