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Space and satellites: awareness and observations

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

Fight against Ebola virus requires more research

2014-10-22

Dr Abdon Atangana
Photo: Ifa Tshishonge

Dr Abdon Atangana, a postdoctoral researcher in the Institute for Groundwater Studies at the University of the Free State (UFS), wrote an article related to the Ebola virus: Modelling the Ebola haemorrhagic fever with the beta-derivative: Deathly infection disease in West African countries.

“The filoviruses belong to a virus family named filoviridae. This virus can cause unembellished haemorrhagic fever in humans and nonhuman monkeys. In literature, only two members of this virus family have been mentioned, namely the Marburg virus and the Ebola virus. However, so far only five species of the Ebola virus have been identified, including: Ivory Coast, Sudan, Zaire, Reston and Bundibugyo.

“Among these families, the Ebola virus is the only member of the Zaire Ebola virus species and also the most dangerous, being responsible for the largest number of outbreaks.

“Ebola is an unusual, but fatal virus that causes bleeding inside and outside the body. As the virus spreads through the body, it damages the immune system and organs. Ultimately, it causes the blood-clotting levels in cells to drop. This leads to severe, uncontrollable bleeding.

Since all physical problems can be modelled via mathematical equation, Dr Atangana aimed in his research (the paper was published in BioMed Research International with impact factor 2.701) to analyse the spread of this deadly disease using mathematical equations. We shall propose a model underpinning the spread of this disease in a given Sub-Saharan African country,” he said.

The mathematical equations are used to predict the future behaviour of the disease, especially the spread of the disease among the targeted population. These mathematical equations are called differential equation and are only using the concept of rate of change over time.

However, there is several definitions for derivative, and the choice of the derivative used for such a model is very important, because the more accurate the model, the better results will be obtained. The classical derivative describes the change of rate, but it is an approximation of the real velocity of the object under study. The beta derivative is the modification of the classical derivative that takes into account the time scale and also has a new parameter that can be considered as the fractional order.

“I have used the beta derivative to model the spread of the fatal disease called Ebola, which has killed many people in the West African countries, including Nigeria, Sierra Leone, Guinea and Liberia, since December 2013,” he said.

The constructed mathematical equations were called Atangana’s Beta Ebola System of Equations (ABESE). “We did the investigation of the stable endemic points and presented the Eigen-Values using the Jacobian method. The homotopy decomposition method was used to solve the resulted system of equations. The convergence of the method was presented and some numerical simulations were done for different values of beta.

“The simulations showed that our model is more realistic for all betas less than 0.5. The model revealed that, if there were no recovery precaution for a given population in a West African country, the entire population of that country would all die in a very short period of time, even if the total number of the infected population is very small. In simple terms, the prediction revealed a fast spread of the virus among the targeted population. These results can be used to educate and inform people about the rapid spread of the deadly disease,” he said.

The spread of Ebola among people only occurs through direct contact with the blood or body fluids of a person after symptoms have developed. Body fluid that may contain the Ebola virus includes saliva, mucus, vomit, faeces, sweat, tears, breast milk, urine and semen. Entry points include the nose, mouth, eyes, open wounds, cuts and abrasions. Note should be taken that contact with objects contaminated by the virus, particularly needles and syringes, may also transmit the infection.

“Based on the predictions in this paper, we are calling on more research regarding this disease; in particular, we are calling on researchers to pay attention to finding an efficient cure or more effective prevention, to reduce the risk of contamination,” Dr Atangana said.

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