The radio telescope at the National Research Foundation's (NRF) Hartebeesthoek Radio Astronomy Observatory (HartRAO) has been recommissioned, after the successful completion of a major engineering project to replace the main bearing in its polar shaft.
According to the NRF, the telescope was built in 1960 as part of NASA's Deep Space programme to send spacecraft to explore the moon and planets.
However, the 26 metre HartRAO telescope exhibited irregularities in its functioning during October 2008, the NRF reveals.
“These irregularities were found to be due to the failure of the main bearing in the polar shaft,” it says. This failure necessitated an immediate shut down of observations in order to prevent potential catastrophic failures, it adds.
According to the president and CEO of the NRF, Albert van Jaarsveld, the 2008 shut down of the HartRAO telescope represented a major blow for Africa as it had lost its only operational radio telescope.
“After consulting various experts on whether the antenna should be repaired, rebuilt on a new mounting, or replaced with a new telescope, we decided that repairing the telescope was the best option,” he says. This decision was fully backed by the minister of science and technology, Naledi Pandor, who made the necessary funding available.
“We are pleased that the HartRAO telescope is functional again. For many years, this telescope has helped the South African and international astronomy communities conduct world class research,” comments Pandor.
According to Pandor, the fact that SA successfully completed such a complex engineering project “underwrites our ability to build and maintain the SKA”.
Project commencement
The NRF says the physical repair process commenced in March 2010, and was successfully completed in July 2010. “This was a significant engineering feat since it had only been done once before, on a sister NASA antenna in Spain.”
The foundation says the repaired Hartebeesthoek telescope was first driven on the new bearing on 20 July, and the first test observations were made on 22 July - exactly one year from the decision to repair.
This was followed by the first spectroscopic and pulsar observations on 23 July followed by the first operational 24-hour Very Long Baseline Interferometry observation session linked with telescopes on other continents, it adds. “That contributes to our measurements of continental drift, on 11 August.”
Routine measurements have since resumed their previous weekly schedule.
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