Duncan Steel • Mar 04, 2019 •
As I write, the Dragon capsule – a spacecraft intended to loft US astronauts into orbit – has been docked with the Space Station for almost 18 hours on its initial test flight. It happens that you will be able to see the station plus capsule passing over New Zealand each evening for the next week or so, before the … Read More
Duncan Steel • Feb 22, 2019 •
The International Space Station (and many other satellites) can easily be viewed passing overhead using the naked eye, so long as you know when to look, and where. But why can we see it, and how does it return so often? In a blog post a few days ago I presented tables of times when the International Space Station (ISS … Read More
Duncan Steel • Feb 19, 2019 •
It’s easy to see the International Space Station passing overhead: you just need to know when and where to look. Oh, and a clear sky. The International Space Station (ISS) regularly passes across New Zealand, a little more than 400 km above our heads – rather less than the distance between Auckland and Wellington. Most of these transits … Read More
Duncan Steel • Feb 12, 2019 •
The ongoing fires in the Nelson-Tasman region have quite rightly provoked much alarm. The response of Fire and Emergency New Zealand, the NZ Police, the NZ Defence Force, and many private individuals, has been magnificent. However, the utilisation of satellite imagery for assessing such fires and then planning and responding is deficient in NZ compared to much of the rest … Read More
Duncan Steel • Feb 09, 2019 •
The area burnt in the ongoing bush fire in the Nelson-Tasman region, largely around Pigeon Valley near Wakefield, can easily be seen in satellite imagery collected in recent days. Earth observation satellites frequently cross New Zealand and, clouds allowing, collect imagery of the land and sea below. In later posts I will discuss such data collection in more detail, but … Read More
Duncan Steel • Feb 05, 2019 •
Apart from the US-provided Global Positioning System (GPS) used by most commercial navigation systems – such as in your car, or mobile phone – there are several distinct networks operated by other space agencies deploying their own satellite fleets. Here I describe the orbits employed by the Russian, European Union and Chinese GNSS constellations. (Part 3 in a series of … Read More
Duncan Steel • Jan 18, 2019 •
The idea of satellites beaming radio communications around the globe was discussed by science-fiction author Arthur C. Clarke in 1945, though he imagined huge geostationary space stations permanently staffed by astronauts who would be needed to change the electronic valves in the onboard radio transmitters. We’ve not been able to watch live cricket matches from around the globe on … Read More
Duncan Steel • Jan 16, 2019 •
What sorts of orbits around Earth do we use for different types of satellite, and why are those paths chosen? In this, Part 1 in a series of blog posts, geostationary orbits are described. Satellites come in all sorts of shapes and sizes, ranging from half the size of a bus down to something not much … Read More
Duncan Steel • Jan 09, 2019 •
With regard to tracking military satellites newly-launched from eastern Asia and potentially of concern to our allies, New Zealand’s geographical position is of huge (yet overlooked) significance. Surely no-one could imagine that space-wise there is not a lot going on at present, with another probe just landed on Mars, three other spacecraft missions having encounters with asteroids, and … Read More
Guest Author • Mar 29, 2018 •
Melissa de Zwart, University of Adelaide This article was originally published on The Conversation. Read the original article. The defunct Chinese space station Tiangong-1 is falling back to Earth and about to crash land some time over the next few days. Most experts expect much of it to burn up as it enters the atmosphere, … Read More