Station Science Top News: July 7, 2023

by ISS Program Science Office | 2023-07-07

Research results suggest that weak X-ray bursts measured from pulsar SAX J1808.4-3658 are triggered by gravitational accumulation of temperature-sensitive hydrogen. Increased observation of weak bursts could contribute to understanding of Neutron burst phenomena and extreme gravity.

The NICER telescope monitors X-ray bursts that cannot be tracked from within the Earth’s lower atmosphere. Researchers captured two types of peak thermo-nuclear bursts from J1808 in 2019 and state that the less frequently studied weaker bursts produce much less energy and show peak fluxes about a factor of 25 less than the bright photospheric radius expansion (PRE) events. The study of extraordinary physics within pulsars may uncover some of the mysteries of ultra-dense matter on the edge of collapse to a black hole.

Learn more here.

View of a radiator pane, solar array and the Alpha Magnetic Spectrometer - 02 (AMS-02) as seen by the External High Definition Camera (EHDC1). Also visible are Neutron star Interior Composition Explorer (NICER) and Materials ISS Experiment Flight Facility (MISSE-FF). — View of a radiator pane, solar array, and the Alpha Magnetic Spectrometer - 02 (AMS-02) as seen by the External High Definition Camera (EHDC1). Also visible are Neutron star Interior Composition Explorer (NICER) and Materials ISS Experiment Flight Facility (MISSE-FF).

***

Researchers report six years of solar electron and proton count rates, validating a method used to determine proton count rates during the 11-year solar cycle. Observations of long-term solar modulation are important in the study of cosmic ray effects on the Earth by the Sun and external sources.

The CALET telescope seeks to detect discrete sources of high energy particles and examine fluctuations of galactic cosmic ray (GCR) intensity. Between 2015 and 2021, the CALET data predicted and verified variations of intensity between GCR and the tilt angle of the Sun’s heliosphere with respect to the Earth’s position in the solar system. These results could improve monitoring of solar particle variation at the Earth’s poles and within the solar system’s heliosphere, which shields planets from particles generated far away in the universe.

Read more here.

Photos of the Imaging Calorimeter (left) and of the Total Absorption Calorimeter. Credit: JAXA — *Photos of the Imaging Calorimeter (left) and of the Total Absorption Calorimeter. Credit: Japan Aerospace Exploration Agency (JAXA)*

***

Researchers report an improved computational fluid dynamic model for predicting changes in coolant fluid behavior as it responds to different physical changes in microgravity. This result allows researchers to make predictions prior to experimentation to improve heat dissipation in space and even suggest which facilities on ISS might need optimization of their cooling systems.

Using high-speed video, FBCE researchers captured the changes occurring in a coolant fluid with varied heat and momentum (i.e., mass velocity) transitioning from its boiling to its condensation phase in microgravity. The computational fluid dynamic model considered turbulence, surface tension, boiling flow, coalescence, and detachment. Parameters show agreement with the experimental interphase and heat transfer data and provide detailed 3D predictions of heat transfer characteristics. Improved control of coolant flow dynamics could enhance heat transfer systems such as those that protect astronauts against the extreme hot and cold temperatures of outer space.

FBCE video.