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Posts Tagged astronomy

Most of us missed this one Ken Perrott Jan 17

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Karl Battams reports (The Mercury Transit You Probably Missed) there was a transit of the sun by Mercury recently. Despite this being a rare event nothing was made of it – because it wasn’t visible from earth!

Here is a video of the transit taken by the NASA STEREO-A satellite At the moment this is on the opposite side of the Sun from Earth.

Fascinating that we have enough presence in the solar system now to make such a record.

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Christmas present from NASA Ken Perrott Dec 16

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Photography can produce some great abstract art. Even if it’s of the very large or very small.

Here’s some really beautiful abstract art based on photograph of earth taken from orbit.

Great-Salt-Desert

The Dasht-e Kavir, or Great Salt Desert, is the larger of Iran’s two major deserts, which occupy most of the country’s central plateau.

From the introduction:

In 1960, the United States put its first Earth-observing environmental satellite into orbit around the planet. Over the decades, these satellites have provided invaluable information, and the vantage point of space has provided new perspectives on Earth. This book celebrates Earth’s aesthetic beauty in the patterns, shapes, colors, and textures of the land, oceans, ice, and atmosphere. The book features 75 stunning images of Earth from the Terra, Landsat 5, Landsat 7, EO-1, and Aqua satellites. Sensors on these satellites can measure light outside of the visible range, so the images show more than what is visible to the naked eye. The images are intended for viewing enjoyment rather than scientific interpretation. The beauty of Earth is clear, and the artistry ranges from the surreal to the sublime.

Earth as art—enjoy the gallery.

NASA Science Mission Directorate

Earth Science Division

Download your gift:

As a PDF

As the Accompanying iPad App

via NASA – “Earth As Art”.

Thanks to ebook friendly

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A sundial on Curiosity? Ken Perrott Aug 15

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When I saw the first reports of this on Twitter I thought it was a joke. A sundial on Curiosity? Just in case the computer packs up they can still tell the time? I thought some wag was pulling our collective legs with a photo of one of the rover’s antennae.

But, turns out this is something like a sundial. Its a Marsdial – actually a calibration target enabling photographs to be corrected for colour. BIll Nye, from the Planetary Society, describes its role in Curiosity’s Marsdial is on Mars!

“As I’m sure you’re aware, geologists love rocks, and they especially love the rocks on Mars. The first thing they all want to know about a rock is what’s it made of. For that, it’s good to just take a look at the color of the rock surface. When everything is being done on the alien landscape of another world, it’s easy enough to electronically get the color wrong, or not quite right. To that end, artists, photographers, and a few scientists have noticed that by looking at the color of a shadow on a neutral white or gray background, you can infer the color contributed to the scene by the sky.

On Earth, shadows take on a sky blue tinge (what I like to call “cerulescence”). On Mars, it’s a salmon color (what I like to call “arangidescence”). And so, the MarsDials bear a small metal post that casts a shadow onto some white and gray rings of known value or grayness.”

The NASA animation above is made up from four Mastcam images of the calibration target — the Marsdial. They were taken on Curiosity’s sol 3 (August 9, 2012) over a period of about 8 minutes. In that time, the shadow moved slightly, marking time on Mars with a sundial. (You may need to click on the photo to see the animation).

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Scientific shift work Ken Perrott Aug 14

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Some of the people on teams managing the rovers on Mars call themselves “Rover drivers” or “Mars drivers.” Of course, things are not that simple. It is not possible to drive a vehicle on Mars in real-time from Earth. Instead, computer code must be uploaded to enable the vehicle to carry out planned manoeuvres, analyses, etc., autonomously.  And the computer code can only be written after the results of the previous commands are known.

In practice, this involves large teams of engineers, software experts and scientists. Each team has their own work – and the teams need to interact to plan the rover’s work, iron out priorities, and deal with problems. This work has to occur at strange times, and with deadlines, to fit in with the activity and day/night programme on Mars. Energy limitations means that the rover usually does not operate during the Martial day.

So all this work, the meetings of each team and their joint meetings, and decisions about planned activity must take place before the rover “wakes up.” And because the results from the previous day’s activities feed into this detailed decision cannot be made and code written until after that data has been downloaded and analysed.

The graphic above was shown in one of the recent Mars Science Laboratory – Curiosity – media briefings. It indicates the time line for the Laboratory to be active (“awake”), the downloading of data via the Mars Odyssey and Mars Reconnaissance orbiters, assessment of data, planning of future activity (particularly that for the next day), interaction of engineering, scientific and software teams, integration of plans, validation and approval and then the sending of the new commands to Curiosity as it “wakes up” for the new day.

I note they have even left a brief time gap “margin” to handle unforeseen problems.

It must be fascinating to work in large teams like this on scientific projects. And I am sure there are also political and emotional problems that need management as well as the engineering, scientific and software problems. Apparently with groups managing Mars rovers the shift-work, and the drift in shift times because of mismatch in the length of the Earth day and the Mars sol, causes “jet lag.” So the emotional and human issues resulting from this also need management.

Andrew Kessler gives an idea of the procedures involved in managing Mars rovers and landers in his book Martian Summer: Robot Arms, Cowboy Spacemen, and My 90 Days with the Phoenix Mars Mission. This is based on his own experiences as a journalist embedded in the teams managing the recent Phoenix lander. It’s a bit of an eye-opener – at least for someone who hasn’t worked in such large scientific teams before.

See Working on Mars for my review of that book.

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Infectious jubilation Ken Perrott Aug 07

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Crowd in New York’s Times Square celebrate successful Mars landing – 1:30 am. Credit: Jason Major (@JPMajor)

The mass interest in the current Olympics, and yesterday’s landing of the Curiosity Rover on Mars really brought home to me that we are an empathetic species. We celebrate the achievements of others and feel the jubilation they do when things go right.

And with Curiosity’s successful landing I think we also celebrate the achievement because we see that it belongs to all of us. It is an achievement for all humanity.

The achievement is huge. The technically difficult landing seemed to go without a hitch. Scientists and engineers at NASA’s Jet Propulsion Laboratory were receiving images within minutes. Everyone was aware that attempts at Mars landing have a history of failure.

The descent by parachute was photographed by a high-resolution camera on board the Mars Reconnaissance Orbiter. – see below.

Photo: NASA – Curiosity Spotted on Parachute by Orbiter.

That seems incredibly lucky but clearly a lot of skill and technology went into this achievement as well. As Phil Plait wrote on Bad Astronomy:

“The simple and sheer amazingness of this picture cannot be overstated. Here we have a picture taken by a camera on board a space probe that’s been orbiting Mars for six years, reset and re-aimed by programmers hundreds of millions of kilometers away using math and science pioneered centuries ago, so that it could catch the fleeting view of another machine we humans flung across space, traveling hundreds of million of kilometers to another world at mind-bending speeds, only to gently – and perfectly – touch down on the surface mere minutes later.”

According to a media briefing earlier today the full version of this image also shows the abandoned heat shield which landed some distance from the Curiosity’s landing site.

Patience

Now we have to be patient while Curiosity is checked out by engineers and slowly brought into full functioning. It will be weeks before the vehicle starts driving around, sampling soil and rocks, and analysing samples.

Even the downloading of images already captured will take time. So far we are only seeing relatively low resolution images. Large teams of engineers and scientists will be working strange hours (the slightly different length of the Martian day (sol) and the Earth day causes “jet lag” for these people) receiving data, planning experiments, writing code and uplifting code and instructions.

Andrew Kessler gives an idea of the activity and life style of the teams involved in managing the last Mars lander – Phoenix – in his book Martian Summer: Robot Arms, Cowboy Spacemen, and My 90 Days with the Phoenix Mars Mission. For my review of this book see Working on Mars.

See also:
Curiosity requires patience
Going for gold – on Mars
Seven Minutes of Terror
Christmas gift ideas: Working on Mars

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Curiosity requires patience Ken Perrott Aug 06

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The Mars Science Laboratory, Curiosity, lands today – hopefully (5:31 pm NZ time). But when will we know if the landing has been successful?

Communication between Mars and Earth is hardly simple. It’s not just the time delays involved (currently about 15 min). There’s also rotation of both planets. So communication with Curiosity (if it lands successfully) will involve three satellites in orbit around Mars – the Odyssey Orbiter, the Reconnaissance Orbiter and ESA’s Mars Express. (Watch this video to see the alignment of Curiosity, Odyssey and Reconnaiscance during landing). Messages, and particularly data, may need to be stored on board Curiosity or the satellites before transmission to earth.

So we may not even have confirmation of Curiosity’s safe landing for several hours – maybe even several days. This video describes the problems and how they are overcome.

Thanks to Universe Today: When Will We Hear From Curiosity?

Curiosity’s landing site

Here’s a computer-generated view of Mars’ Gale crater as if seen from an aircraft north of the crater. Because of its history, 96-mile wide Gale Crater crater landing site is an ideal region for exploration of the planets history.

It has thick exposed sections of layered sedimentary rocks with a wet history. Joy Crisp, Mars Science Laboratory Deputy Project Scientist from NASA’s Jet Propulsion Laboratory said:

“The rock record preserved in those layers holds stories that are billions of years old — stories about whether, when, and for how long Mars might have been habitable.”

For further information go to Image of the Day –NASA’s Gale Crater Mars Landing Site for Tomorrow’s ‘Search-for-Life’ Mission.

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Going for gold – on Mars Ken Perrott Aug 05

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Artist’s impression of Curiosity Rover on Mars. Credit: NASA

I know Kiwi readers are going to have a hard time dragging themselves away from TV coverage of the London Olympics – and our current ranking in the medal tables – but it’s worth putting in an effort early Monday evening for the planned landing of Curiosity on Mars. This is scheduled for 5.31 pm New Zealand time – between the reruns of New Zealand Olympic triumphs on afternoon TV and live coverage of the new days activity in the evening.

There will be a number of sites streaming live coverage, but the NASA TV  is a safe bet. When I say live – it will be live coverage of the the scientists and engineers behind the attempt, and their reaction to incoming data. There is a camera on board the probe which will record video but that won’t arrive on earth for a few days. But those scientists and engineers are going to be pretty emotional – it will be a bit like one of those attempts at Olympic gold medals we have followed lately.

I imagine that space enthusiasts around the world will be organising their own parties and venues to follow coverage. NASA coverage will even be broadcast publicly in Times Square, New York. OK, landing is at 1:30 am local time – but they say New York is the city that never sleeps.

My earlier post Seven Minutes of Terror has a video showing the complexity of the landing operation. There is obviously a large chance of failure, because much of the landing technology is new. This will add  to the excitement and tension of the video coverage.  If successful, Curiosity will be largest rover yet to land on Mars. This image gives some idea of its size

Credit: NASA

It’s really a mobile laboratory and  will search for any evidence of past or present habitable environments in the Gale Crater area. Curiosity has mast-mounted instruments for surveying its surroundings and identifying potential sampling targets. Instruments on its robotic arm will enable close-up inspections. Sample of rock, soil and atmosphere will be analysed by instruments inside the rover. Even during its descent sensors on the heat shield will collect information on the atmosphere.

Curiosity’s initial planned programme provides for 1 year of investigations, and may be extended depending on funding and performance. It’s going to be fascinating to see what this rover discovers. Discovery of life, or potential habitats for life, or even evidence of past life will create wide interest. But even negative results will give valuable insight into the similarities and differences  between early Mars and early earth.

Let’s not forget that there is always a large team behind space probes and rovers like this. The photo below showing 2/3rds of the team behind Curiosity give some idea of its size.

Credit Allen Chen: @icancallubetty

And for those who love toys – Mattel Inc., who manufacture a die-cast line of Hot Wheels toy cars, is ready to release the car-size Curiosity as its latest 1:64 scale miniature in September. The Hot Wheels “Mars Rover Curiosity” set is part of Mattel’s assortment of 247 toy cars for 2012.


For posts on the landing and work of the last Mars lander see:
Good luck Phoenix!
Phoenix has landed!
Working on Mars

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Emotional time for Shuttle fans Ken Perrott Apr 20

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Click to enlarge

There have been some great photographs online showing the last flight of the Shuttle Discovery  atop a modified Boeing 747 Shuttle Carrier Aircraft. Headed to its resting place as an exhibit at the Smithsonian’s National Air and Space Museum Udvar-Hazy Center.

This is one of my favourites.

Thanks to Astronomy Picture of the day (2012 April 19 – Discovery Departs).

A fuzzy photo of the sun Ken Perrott Mar 22

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But a great one, when you realise who took it and from where.

It’s actually a shot of the transit of Mars’s moon Deimos, (the smallest and outermost one) across the face of the sun. Photographed from the surface of Mars by the rover, Opportunity, on March 4, 2004.

Deimos – photographed by he Mars Reconnaissance Orbiter.

 

Deimos is only about 12.4 km in diameter – pretty small. So it’s an amazing photo – especially when you realise that the rovers weren’t actually designed for this sort of thing.

And here’s an artist reconstruction of the rover Opportunity on Mars.

Artist’s reconstruction of Rover on Mars. Credit: Wikipedia

Thanks to An Astronomical Photo-Op – Brad BlogSpeed.

Mindboggling Ken Perrott Feb 27

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Click image for larger version

Douglas Adams says in The Hitch-hikers Guide to the Galaxy:

“Space is big. Really big. You just won’t believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.”

The immensity of the galaxy almost seems beyond human comprehension. But this image does start to bring it home to me. It shows the extent of penetration of human radio signals into our galaxy since we have had radio. It’s that small blue dot, 200 light years in diameter, you can see in the enlarged section.

And our galaxy is only an extremely small and irrelevant part of the universe.

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