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19 November 2024 | Story Pat Lamusse | Photo Supplied
Space and satellites 2024
During the visit to the Naval Hill Planetarium, were from the left, Dr Mart-Mari Duvenhage and Prof Matie Hoffman from the UFS Department of Physics, Consul General Stephanie Bunce and Vanessa Toscano from the US Consulate, and Dinah Mangope from the Department of Physics.

A delegation from the United States (US) Consulate General in Johannesburg, including Consul General Stephanie Bunce and Public Affairs Officer, Vanessa Toscano, visited the Bloemfontein Campus of the University of the Free State (UFS). Consul General Bunce met with the acting Vice-Chancellor and Principal of the UFS, Prof Anthea Rhoda, and the Dean of the Faculty of Natural and Agricultural Sciences, Prof Paul Oberholster. The US delegation also visited the Naval Hill Planetarium.

The UFS recently received a grant from the US Embassy to fund a project to promote science education by highlighting the role of satellites in our lives. Colleagues from the Department of Physics had the opportunity to demonstrate first-hand how the planetarium technology will be used to implement the project, which poses the question – what if something happens in space that interferes with the thousands of satellites we use for communication, weather prediction, navigation, banking … surveillance?

Thanks to this grant, the UFS will explore these questions and contribute to space situational awareness (SSA) and space domain awareness (SDA). SSA involves knowledge about the orbits of spacecraft and space debris. SDA refers to the knowledge and understanding of all activities occurring within the space domain.

There are currently at least 10 000 active satellites in Earth orbit, most of which are in low Earth orbit (LEO). However, in addition to satellites, there are well over 45 000 objects larger than 10 cm in orbit, including more than 35 000 pieces of space debris, such as dead satellites, rocket bodies, and pieces from breakups and collisions. Since 1991, there have been at least six unintentional collisions between active satellites and space debris.

Space turned out to be not as big as once thought, especially not in low Earth orbit (LEO – altitude less than 2 000 km). To make things worse, there are plans to launch up to 100 000 new satellites into LEO over the next decade.

Prof Matie Hoffman from the UFS Department of Physics notes, “We live in an era when the space economy is growing fast and the number of objects in Earth orbit, including satellites and space debris, is increasing rapidly. This poses risks to operational satellites. Recent publicity around Elon Musk’s Starlink satellites has generated additional interest around this topic. It is important to raise awareness of the challenges, which will allow scientists to mitigate them.”

The project will involve expertise in optical satellite observations from the University of Michigan through Prof Patrick Seitzer, international patron of the Friends of Boyden Observatory, and the American Museum of Natural History (AMNH). The grant will fund planetarium upgrades that will enable education on space and satellites, as well as optical satellite observations from Boyden Observatory. Beneficiaries will include learners, higher education institutions (both locally and in the US), and the public. South African project partners will be the South African National Space Agency (SANSA), the Future African Space Explorers’ STEM Academy (FASESA), and satellite-related companies in South Africa.

The Boyden Observatory is ideally situated to provide valuable optical satellite observations in an area of the sky that is not accessible from existing satellite observing facilities, especially for objects in LEO. In fact, the first observation of space debris in geosynchronous orbit was from Boyden Observatory in 1967.

The project will be rolled out from the end of 2024, harnessing facilities at both Boyden Observatory and the Naval Hill Planetarium.

News Archive

Research eradicates bacteria from avocado facility
2017-01-17

 Description: Listeria monocytogenes Tags: Listeria monocytogenes

Listeria monocytogenes as seen under an electron
microscope. The photo was taken with a transmission
electron microscope at the microscopy unit of the UFS.
Bacteriophages (lollipop-like structures) can be seen
next to the bacterial cells.
Photo: Supplied

“The aim of my project was to identify and characterise the contamination problem in an avocado-processing facility and then to find a solution,” said Dr Amy Strydom, postdoctoral fellow in the Department of Microbial Biochemical and Food Biotechnology at the University of the Free State (UFS).

Her PhD, “Control of Listeria monocytogenes in an Avocado-processing Facility”, aimed to identify and characterise the contamination problem in a facility where avocados were processed into guacamole. Dr Strydom completed her MSc in food science in 2009 at Stellenbosch University and this was the catalyst for her starting her PhD in microbiology in 2012 at the UFS. The research was conducted over a period of four years and she graduated in 2016. The research project was funded by the National Research Foundation.

The opportunity to work closely with the food industry further motivated Dr Strydom to conduct her research. The research has made a significant contribution to a food producer (avocado facility) that will sell products that are not contaminated with any pathogens. The public will then buy food that is safe for human consumption.


What is Listeria monocytogenes?

Listeria monocytogenes is a food-borne pathogenic bacterium. When a food product is contaminated with L. monocytogenes, it will not be altered in ways that are obvious to the consumer, such as taste and smell. When ingested, however, it can cause a wide range of illnesses in people with impaired immune systems. “Risk groups include newborn babies, the elderly, and people suffering from diseases that weaken their immune systems,” Dr Strydom said. The processing adjustments based on her findings resulted in decreased numbers of Listeria in the facility.

The bacteria can also survive and grow at refrigeration temperatures, making them dangerous food pathogens, organisms which can cause illnesses [in humans]. Dr Strydom worked closely with the facility and developed an in-house monitoring system by means of which the facility could test their products and the processing environment. She also evaluated bacteriophages as a biological control agent in the processing facility. Bacteriophages are viruses that can only infect specific strains of bacteria. Despite bacteriophage products specifically intended for the use of controlling L. monocytogenes being commercially available in the food industry, Dr Strydom found that only 26% of the L. monocytogenes population in the facility was destroyed by the ListexP100TM product. “I concluded that the genetic diversity of the bacteria in the facility was too high and that the bacteriophages could not be used as a control measure. However, there is much we do not understand about bacteriophages, and with a few adjustments, we might be able to use them in the food industry.”

Microbiological and molecular characterisation of L. monocytogenes

The bacteria were isolated and purified using basic microbiological culturing. Characterisation was done based on specific genes present in the bacterial genome. “I amplified these genes with polymerase chain reaction (PCR), using various primers targeting these specific genes,” Dr Strydom said. Some amplification results were analysed with a subsequent restriction digestion where the genes were cut in specific areas with enzymes to create fragments. The lengths of these fragments can be used to differentiate between strains. “I also compared the whole genomes of some of the bacterial strains.” The bacteriophages were then isolated from waste water samples at the facility using the isolated bacterial strains. “However, I was not able to isolate a bacteriophage that could infect the bacteria in the facility.

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