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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

Sunflowers are satellite dishes for sunshine, or are they?
2016-07-20

Eighty-six percent of South Africa’s
sunflowers are produced in the
Free State and North West provinces.

Helen Mirren, the English actress, said “the sunflower is like a satellite dish for sunshine”. However, researchers at the University of the Free State (UFS) have found that too much of this sunshine could have a negative effect on the growth of sunflowers, which are a major source of oil in South Africa.

According to Dr Gert Ceronio from the Department of Soil, Crop, and Climate Sciences at the UFS, extremely high soil temperatures play a definite role in the sprouting of sunflower seedlings. Together with Lize Henning, professional officer in the department, and Dr André Nel from the Agricultural Research Council, he is doing research on biotic and abiotic factors that could have an impact on sunflowers.

Description: Sonneblom 2 Tags: Sonneblom 2

Various degrees of deformity (bad-left
to none-right) in seedlings of the same
cultivar at very high soil temperatures.
Photo: Dr Gert Ceronio

Impact of high temperatures on sunflower production

The Free State and North West provinces, which produce 86% of South Africa’s sunflowers, are afflicted especially by high summer temperatures that lead to extremely high soil temperatures.

Dr Ceronio says: “Although sunflower seeds are able to germinate at temperatures from as low as 4°C to as high as 41°C, soil temperatures of 35°C and higher could have a negative effect on the vegetative faculty of sunflower seedlings, and could have an adverse effect on the percentage of sunflowers that germinate. From the end of November until mid-January, this is a common phenomenon in the sandy soil of the Free State and North West provinces. Soil temperatures can easily exceed the critical temperature of 43°C, which can lead to poor germination and even the replanting of sunflowers.”

Since temperature have a huge impact not only on the germination of sunflower seeds, but also on the vegetative faculty and sprouting of sunflower seedlings, Dr Ceronio suggests that sunflowers should be planted in soil with soil temperatures of 22 to 30°C. Planting is usually done in October and early November. Unfortunately, this is not always possible, as soil moisture is not optimal for growth. Farmers are then compelled to plant sunflowers later.

Impact of herbicides on sunflower growth

“High soil temperatures, combined with the herbicide sensitivity of some cultivars, could lead to the poor development of seedlings," says Dr Ceronio.

The use of herbicides, such as ALACHLOR, for the control of weeds in sunflowers is common practice in sunflower production. It has already been determined that ALACHLOR could still have a damaging effect on the seedlings of some cultivars during germination and sprouting, even at recommended application dosages.

“The purpose of the continued research is to establish the sensitivity of sunflower cultivars to ALACHLOR when exposed to high soil temperatures,” says Dr Ceronio.

 

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