Duncan Steel

Duncan Steel is based in Nelson but works for the Xerra Earth Observation Institute with its HQ in Alexandra. He has worked in space research for almost forty years, with times spent with NASA, ESA, various universities and observatories, and also running his own company. Duncan is the author of four books, over a hundred research papers, and more than a thousand articles for newspapers and magazines. He has also appeared in hundreds of radio and TV programmes. Minor planet/ asteroid (4713) Steel is named for him, as is a lunar-roving robot in one of Arthur C. Clarke's SciFi novels.

Harry Hindmarsh Atkinson: obituary - Out of Space

Jan 27, 2019

Harry Atkinson in 2012 (courtesy William Tobin). Harry Atkinson was one of those able New Zealanders who went overseas to study, fully intending to return one day to these shores to live, but due to their great success in their adopted homelands never did so. A physicist by training, he moved into science advice and administration in Britain and rose to considerable heights both within the UK Government and also international organisations such as the European Space Agency. Dr Harry Hindmarsh Atkinson (HHA) was born in Wellington and came from a prominent NZ family, his paternal grandfather being Harry Albert Atkinson (HAA), four-time Prime Minister between 1876 and 1891. The Atkinsons were related by marriage to the Richmond family (see also here), who were also active in politics. HAA had three children by his second wife, the … Read More

Satellite Orbits: Global Positioning System - Out of Space

Jan 24, 2019

Most of us use GPS everyday in some way, either driving in our cars or finding our way on a map displayed on our smart phones as we walk around town. Few know what sorts of orbits are occupied by the satellites making all this possible, though. (Part 2 in a series of posts concerning satellite orbits.)   In a previous post I described satellites in geostationary orbit, these remaining above one point on the equator and being used for radio communications or whole-disk imaging of the Earth for meteorological and other purposes. Such satellites take precisely one sidereal day (almost four minutes short of a mean solar day) to orbit the planet, travelling at a speed just above 3 km/sec (11,000 kph). The geostationary altitude is around 35,790 km above the equator, making it 42,168 km from … Read More

The invention of the geostationary communications satellite - Out of Space

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 television for very long. When I was a child in the UK in the 1960s we would need to wait for days for film of major events in the US to be flown across the Atlantic and shown on TV. After I first arrived in New Zealand in 1982, highlights of British football games played on a Saturday were shown on TV the Sunday afternoon eight days later – unless the tape missed the flights out. The introduction of rapid, … Read More

Satellite Orbits: Geostationary - Out of Space

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 bigger than your mobile phone. Indeed if one counts the International Space Station as being a satellite – as we surely must – objects constructed in orbit can be larger still. My intent in this series of blogs is to describe different types of satellite orbit around Earth (geocentric orbits), and the uses to which they are put. It’s all quite simple, and I hope that educators might find the series (and in particular the graphics and movies) useful. Read More

Space War and NZ’s Position - Out of Space

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 many other announcements showing how our exploration of the solar system is proceeding apace. Exciting times. In future posts I will turn my attention to several of these giant leaps, but immediately there is something more important to discuss and closer to home. In the latter half of 2018 the announcement by the present President of the United States that the nation would be establishing a new service within the US military, a ‘Space Force’, attracted much derision in the … Read More

It’s crowded at the edge of the solar system   - Out of Space

Jan 01, 2019

Looking out at the stars it would be easy to think that the solar system is mostly empty, bar the handful of planets circuiting the Sun and the occasional comet we see passing by. The reality, we now know, is that the edge of the solar system contains a vast population of substantial objects orbiting just beyond Neptune, one of which is currently being visited by NASA’s New Horizons spacecraft.   Sometimes the mechanics of the heavens lead to things happening at inopportune times. I am not talking about astrology. What I mean is that NASA’s New Horizons spacecraft is just flying past a minor planet out beyond the orbits of Neptune and Pluto, and it’s January 1st. That will have played havoc with the seasonal festivities of all involved – heck, I’ve been following the events … Read More

Numbering our New Years - Out of Space

Dec 31, 2018

New Year is coming in a few hours (as I write), at least on the calendar used as the global standard. Not everyone counts years in quite the same way, though.     It takes most of us a week or two to get used to the number of the year having changed. In the days when we still wrote cheques, the first few such slips of paper each year would often carry the signs of hasty corrections in the very last digit at upper right. But imagine what it is like if you also use a different dating system to that which has become the world standard. In my preceding post I wrote about how our common dating system uses a radix defined by the traditional day of the circumcision and naming of Jesus Christ: 1st January in … Read More

And so this is Christmas… - Out of Space

Dec 19, 2018

The date of Christmas is a matter many find confusing, and yet the adopted anniversary is easy to understand if you follow through the history, astronomy and human biology that are involved.  Why is the Nativity commemorated on December 25th, when it is clear Jesus was not actually born on that date? And how can a year be termed “Before Christ” if he was born in that year? This is a topic that crops up often in the media and online discussions as the holiday (‘holy day’) season approaches… and yet I have never seen a correct explanation being given. The answers are a mixture of science (astronomy and physiology), religious observances and historical contingencies, but if one follows it through step by step it’s all quite simple. Before going further I should make clear that I have no religious … Read More

Skywatching southerners have chance to see selenelion this Saturday morning - Out of Space

Jul 26, 2018

A few minutes after 8am this Saturday those further south in New Zealand will have a once-in-a-lifetime chance to witness a rare celestial event: a selenelion (or selenehelion). What is that? It’s when the eclipsed Moon can be seen on one horizon, whilst the rising Sun can also be observed near the opposite horizon. One might think this to be impossible – because an eclipse occurs when the Sun, Earth and Moon are in a straight line, and so if the Moon is above the horizon then the Sun must surely be below it. But the bending (refraction) of the rays of light caused by our atmosphere makes it feasible to see both the eclipsed Moon and the Sun at the same time — so long as you are in the right place. The areas of our … Read More