Pushing frontiers in satellite research

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Singapore – Singapore’s Nanyang Technological University (NTU) has launched two more satellites to collect data on Asia’s tropical climate, test new navigation and communications systems and evaluate hardware to protect satellite’s memory.

The Satellite Research Centre (SaRC) in NTUs School of Electrical and Electronic Engineering (EEE) developed the two satellites, which are called VELOX–CI and VELOX–II respectively. The SaRC scientists had previously also built and launched four other satellites, including the X–Sat, Singapore’s first locally built satellite.

The two VELOXes hitchhiked on the Indian Space Research Organisation’s Polar Satellite Launch Vehicle, which was sent into space from India’s Satish Dhawan Space Centre in December 2015.

Supported by Singapore’s Economic Development Board, the mini–fridge–sized, 123kg VELOX–CI will orbit Earth for three years and gather data about Asia’s tropical climate and weather, including its upper atmospheric temperature, humidity, pressure and total electron count. This information will be useful for long-term climate studies.

It will also test NTU’s new Global Positioning System (GPS) hardware and software, which can determine a satellite’s position and velocity to within fifteen centimeters and few millimeters per second accuracy respectively. NTU scientists will be able to use this technology to better pinpoint the VELOX–CI’s real–time position and reconstruct its trajectory. By applying an advanced signal processing technique to the data, they can also ascertain the satellite’s orientation.

The smaller, 12kg VELOX–II’s main mission is to test an innovative and space–qualified data relay technology developed by Singaporean firm Addvalue Innovation. Traditional satellite communications systems that use radio signals require a line of sight, which means that a satellite would only be able to link to NTU, for example, when it is near Singapore. A satellite with the new relay technology could be contacted by NTU from anywhere in the world.

VELOX–II also contains a fast GPS tracking algorithm developed by NTU that can determine its position accurately within one minute.

The satellite will also be used to evaluate new radiation–resistant hardware designed by EEE to protect the critical data stored in a satellite’s memory. Energetic particles found in space and caused by cosmic rays and solar flares could erode satellite’s memory and lead to mission failures. The EEE hardware is an integrated circuit that can detect and correct small errors in the memory.

NTU established radio contact with both VELOX–CI and VELOX–II during their first ground pass, and the telemetry data showed that both satellites had deployed their solar panels and communication antennas successfully. The subsequent in–orbit experiments have demonstrated that they performed according to the design specifications.

Professor Low Kay Soon, director of the SaRC, said: “Our satellite team has worked very hard over the past few years to advance our satellite technology. What makes us so unique is that we have the capability to complete the design and development of satellite missions in different classes, from micro–satellites to nano- and pico–satellites.”

The scientists are now working on a series of nano-satellites. Their next one slated for space, called AOBA VELOX–III, will be launched by the Japan Aerospace Exploration Agency in 2016.