Lecturer: Anders Svedevall et al.
Date: 2013-05-28 10:30
Place: Aula

REXUS/BEXUS - SOLAR from space education to spacesoldering

Large funding is required each year for maintaining the International Space Station (ISS) due to
components in need of replacement. The cost of this maintenance could be reduced by repairing
equipment on site. However, the current method of soldering joints in reduced gravity generates
defective components, thus making the repairs insufficient in outer space.
The main problem is to solder metals in reduced gravity without obtaining an increase of void
fractions, which are inherent due to the lack of buoyant forces on flux and gases. Earlier tests done
by NASA, in reduced gravity alone, show an increased amount of void fraction by up to three times
as compared to solder created in normal earth gravity.
The proposed solution is to solder in a reduced gravity and low pressure environment which enables
minimization of void fractions. In vacuum a repairing sequence can be simulated similar to the
setting at the ISS but with a reduced pressure. The experiment will be able to melt three samples in
vacuum environment and three samples in pressurized environment. To ensure accurate data the
solder joints will be melted and cooled while in milligravity.
This is carried out as the REXUS experiment SOLAR (Soldering Alloys in reduced gravity) in
cooperation with several space agencies throughout Europe.
The SOLAR experiment was launched with a sounding rocket from Esrange Space Centre, Kiruna
(Sweden) in May 2013.
After the flight the samples has been analysed at the Kemi-Tornio University of Applied Sciences
in Finland by using an X-ray scanner to inspect the void fractions in two dimensions.
The result of the reduced gravity soldering is being compared to the similar studies done in the
SoRGE and CLEAR projects by NASA, and to the samples created in the pressurized environment
of the SOLAR experiment. Suggestions on how to obtain improved soldering joints in space will be
given based on the final test results.

Created 2013-05-23 13:02:38 by Uwe Raffalski
Last changed 2013-05-23 13:11:27 by Uwe Raffalski