Friday, November 25, 2016

A map of all the space junk that has re-entered over Australia

Today someone wrote to me to ask for help in identifying a piece of space junk which had been found in Queensland some years ago. Dr Space Junk is always happy to help, so I sent off a brief explanation.

This made me think, though, of how interesting it would be to map the location of all known re-entry events. There'd be a whole bunch of Skylab in Western Australia, some material from the Europa launches from Woomera in the 1960s in the Northern Territory and Queensland, and many pressure vessels used in rocket fuel systems - globally, these are the most common component to survive re-entry as they're usually made from titanium, stainless steel and/or carbon-carbon. Because of Australia's location, many rocket bodies fall back to Earth over our landmass. We're well situated for observing and tracking the LEOP (Launch and Early Orbit) phase of launch so it makes sense that the second and third stages are likely to re-enter in our vicinity.

You could compare the distribution of this junk with the meteorite entries being mapped by the Western Australian Fireballs in the Sky project, which asks citizen observers to send in data whenever they see some flaming object heading towards Earth. And of course there's also the tektite strewn fields.

I might just expand it to include anything that falls from the sky, as it's likely there's stuff that my Friday-arvo brain has forgotten about at the moment. The more I think about it, the more I think this could be an extremely interesting map to create and I wonder why I've not thought of it before. Such a deliciously simple idea that could lead to - well I don't really know just yet, but it's sure to be something!

Sunday, November 06, 2016

Do objects and people cast shadows inside the International Space Station?

Do astronauts cast shadows in space?

Astronaut Mike Hopkins casts a spoon shadow. Image courtesy of NASA.

I've been thinking about shadows a lot, and also space stations. This has involved reading about habitability studies, an area I started to investigate when I was writing about Skylab a few years ago. The point of this line of enquiry is whether shadows are considered when the interiors of space stations are designed. Perhaps they contribute to creating a feeling of homeliness. Perhaps a lack of shadows is something characterising a laboratory environment, or a solitary confinement cell, or a padded cell, and hence to be avoided. Astronauts are, after all, under constant surveillance. You can hide things in shadows. Things can hide themselves in shadows.

It's worth observing that a shadowless environment can occur when you have no light, or when you have too much light.

Part of the answer to this is how, when, where and with what the ISS is illuminated. It appears that the lighting at present is a combination of fluorescent and LED.  

A perusal of images of the interior shows that there are certainly shaded areas, and more highly illuminated areas. The restricted interior space, and the curvature will also have an impact on the appearance of shadows. Have a look at this one:

Image courtesy of NASA
Of course, when we see images of the inside, they are generally illuminated. But the space station is also darkened at 'night'.  Recently astronaut Alexander Gerst took a series of rather spooky pictures with the lights turned off. Clock this and tell me it doesn't send chills down your spine:

Image courtesy of NASA
Do you see that the helmets are hooded? Is this from fear of what you might see if you looked through the visor?

Perhaps illumination inside the ISS is designed to avoid the ever-present uncanny, always just out of sight, in another module, or outside the window....

Monday, October 03, 2016

Tsiolkovsky imagines the Earth seen from orbit in 1920

In 1920, the great Russian space visionary Konstantin Tsiolkovsky published Outside the Earth, in which Galileo, Newton, Franklin, Helmholtz, Ivanov and Laplace build a rocket. Along with a crew of 16 men, their colleagues elect Newton, Laplace, Franklin and Ivanov as first cosmonauts, while they stay behind in the Himalayan castle the scientists had built as a retreat from the world. 

It's a charming conceit, which Tsiolkovsky uses as a didactic device to explore all kinds of practical aspects of human spaceflight. What makes it especially interesting, from my perspective, is that he also creates a phenomenology of space through translating science into the experience of a human body. This is a theme which permeates his work, and he's rather brilliant at it.

In the passage below, he describes the Earth as it appears from orbit. I'll remark upon a few points of interest when you've finished reading it.

The Earth, taken from TIROS-1 in 1960.
Image courtesy of NASA
Men at the other portholes saw the Earth at a distance of a thousand kilometres. They didn't realise at first that they were looking at the terrestrial globe. But then they began to recognise the familiar contours of lakes and islands and continents amidst patches of clouds. It was like a huge, distorted map of a hemisphere. In actual hemisphere maps, the edges are clear and their scale is double that of the central portion. Here the reverse was true: the edges were reduced radially and very vague.
"...The edges are uneven and in some places they're jagged because of the mountain peaks. Something like a mist lies further in from the edges and there are many elongated grey spots - clouds darkened by the thick layer of the atmosphere. The spots stretch around the Earth's circumference. The further they are from the edges the lighter and broader they seem, and toward the centre they're rounded or irregular in shape, not stretched out".
"....Gentlemen," Newton said, "our rocket is circling the Earth once every 100 minutes. The solar day lasts 67 minutes, and the night, 33 minutes. In 40 or 50 minutes we shall enter the Earth's shadow. the Sun will set almost instantaneously. We'll hardly see the moonlit Earth, but its edges will shine brightly with all the colours of the dawn. This light will be our substitute for moonlight.
I'm warning you in advance what to expect to prepare people whose nerves are not strong..."
Meanwhile the Earth continued to wane and at the terminator the oblique shadows of mountains and elevations grew longer and longer. The impression was as if the stars were falling to the jagged sunlit edges of the Earth in tens, hundreds and thousands, so large was the portion of the sky occupied by the Earth and so great was the number of stars that could be seen in the void....they could see cities, large villages, rivers more than 100 metres wide. Sometimes the land below assumed one colour, as if covered with snow, and it was difficult to see anything....
The sky was so tightly packed with stars that there was hardly an empty space left: a black sky powdered with silver stardust, with the exception of the so-called coal-sacks, which were as black and empty as viewed from the Earth.
Binary, ternary, multiple and vari-coloured stars could be seen everywhere. The moment of eclipse, or night, was approaching.

It takes a little while for the rocket crew to realise that they are even looking at the Earth. Tsiolkovsky notes the difference from the world as portrayed in maps, which are always projections which have to be distorted in various ways to accommodate the globe to two dimensions. To these cosmonauts, it is the world which seems distorted rather than the more familiar map projections.

For us, in nearly 2020, the image of the blue Earth is so entrenched in our collective consciousness that it comes as surprise to see this feature absent from Tsiolkovsky's vision. However, right up until the 1960s, many depictions of the Earth from the outside were in grey tones. Even when Major Tony Nelson and Jeannie went into space, the Earth was greyscale. This was partially because many of the images from early human spaceflights and satellites, like TIROS 1, were taken with black-and-white film.

Tsiolkovsky argued that the atmosphere made the sky appear blue when on Earth, and outside the atmosphere, this effect was removed. Nonetheless, the Earth is in fact blue when seen from space, because of the oceans. This was something that he didn't predict, for all his feats of imagination.

From Tsiolkovsky's Album of Space Travel, 1933.
Image courtesy of the Russian Academy of Science

At a distance of 1000 km, especially in the 1920s, it is unlikely that our fictional cosmonauts would have seen many signs of human occupation. Large cities, perhaps, but probably not large villages. In 1962, Yuri Gagarin orbited at around 200 km. In a speech given after his return, he said that "Clearly distinctive are large mountain ranges, large rivers, large forest areas, shorelines and islands".  No Great Walls of China!

Newton issues a warning that the sight of the Earth passing into the shadow of night might be a bit much for some. I'm reminded of Asimov's classic story Nightfall (1941), in which the sight of the stars in the first black night for two thousand years causes madness. And indeed viewing this unfamiliar hyperobject does have its effects:

The men were stunned by the sight, some felt exhausted and moved away from the portholes. Other, alarmed by their cries, hesitated to look out. Many flew away to their cabins, drew the shutters, and lit dim electric lights. Others, however, darted excitedly from porthole to porthole with cries of surprise and delight.

I think this is what I like most about Tsiolkovsky's vision, that he takes into account the emotions, and allows for different reactions to this extraordinary experience. And there's no 'Overview Effect'. I have a healthy skepticism about the presumed universal experience of the Overview Effect - the feeling, described by so many astronauts when they go into orbit, of deep connection to a fragile world where humanity is united. There is no doubt something significant here, but the trope is so strong that you rarely hear dissenting views, such as those of African-American astronaut Mae Jemison. Astronauts are such a narrow and elite class; as diversity in their ranks grows, there will no doubt be more diverse reactions to the overview.

Finally, I note that our intrepid scientists and their crew do not appear on the rather wonderful Wikipedia list of fictional astronauts, for which they meet all the criteria. I might have to do something about this!

Tsiolkovsky, K. 1920 [nd] Outside the Earth. In V. Dutt (ed) The Call of the Cosmos, pp 161-332. Moscow: Foreign Languages Publishing House

Wednesday, August 24, 2016

From aerospace to everyday life: the trajectory of cable ties.

This is our poster for the World Archaeological Congress in Kyoto in a few days time! My co-author is the wonderful Aylza Donald, who has caught the cable tie love.

Saturday, July 30, 2016

A funny thing happened on the way to the spaceport

Back in 2005, I was lucky enough to visit the Centre Spatial Guyanais in French Guyana. This is where the Ariane rockets are launched. It was amazing. I spent a couple of days in the archives, and drank a lot of ti-punch. Later, I incorporated some of my research into an article.

There were a few other people on the official part of the visit, and we took a group shot at the end. An acquaintance thought it might be amusing to re-imagine the Kourou spaceport as a landing rather than a launching site.....

Friday, June 03, 2016

"Tonight she was glittering and wild": an eclipse of the moon.

A couple of years ago I made an excursion into lunar poetry to commemorate the 45th anniversary of the Apollo 11 moon landing in 1969. At the moment I'm investigating the cultural significance of the entire moon in the context of proposed lunar mining. A random train of connections led to this evocative poem by Elizabeth Ridell. I like the conjunction of small domestic events and sensations with the astronomical event happening in the skies above, and the moon wild and glittering.....

Eclipse of the Moon

Elizabeth Ridell

This is a profitable night, the moon’s eclipse
at last a reason for not sleeping.
There is a reason to wake every hour
to observe the shape and size of door and window
and wall and picture frame,
turn on the lamp, open the book
and let it fall away, reason to rise, make tea,
pad to the door,
stand on cool tiles
to watch the invaded moon.
I see a jagged one third of her beauty left
and somewhere, black layers back,
a rim of light.
Sometimes the moon strays into daytime skies
Tonight she was glittering and wild
until the mask slid down,
erasing all her gold.

Source: The ABC Book of Australian Poetry: a treasury for young people compiled by Libby Hathorn (ABC Books 2010)
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