Tag Archives: juno

Catching up with Cassini

August 20, 2011   admin   No comments

Cassini has to considered to be the quiet achiever of space probes.

It left Earth in 1997, arriving at Saturn in 2004. After Huygens touched down on Titan, Cassini has largely been forgotten by the public while superstars like the Voyager twins set new distance and longevity records, and the Spirit and Opportunity rovers discover an ancient, wet Mars.

And yet, Cassini soldiers on, quietly studying the Saturnian system. In fact, it’s been doing such a good job (and is still in good working order) that it’s had it’s mission extended 2017.

I felt that it needed some recognition, so this week’s update for the Pro edition of Solar Explorer  features a detailed Cassini model.

A lot of work it was too.

Unlike Juno, Cassini has exposed instruments and struts all over it, which made it hard to convert to polygons. I’m getting the hang of spotting “shortcuts” now, so I was still able to come in well under my 2,000 polygon budget, to keep the speed up on all classes of Android devices, while keeping the model reasonably accurate.

My favourite feature of Cassini would have to be the sinister looking thermoelectric power generators that stick out around the base of the craft. Each of these produces electricity for the from heat generated by the radioactive decay of plutonium stored within the generator.

They kind of remind me of a Dalek’s gun from Dr. Who.

New Horizons, currently on it’s way to Pluto, got the Dalek ray gun treatment too, with a spare generator left over from Cassini bolted on.

There’s still lots more to come for Solar Explorer, but there’s only so many hours in a day…

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A double release

August 11, 2011   admin   1 Comment

In this weeks update, I added a couple of new planet structure definitions for Saturn and Uranus into Solar Explorer.

I’d been putting these two off for a while since they have rings and the code I wrote to swap the planet between the cutaway view and normal view couldn’t handle them, so they were just vanishing. I decided to just go for it and modified the code to smoothly fade the rings back in.

I also upgraded to the latest beta compiler for Shiva which brought some performance enhancement to more recent CPUs. This also resolved the bug that had stopped me releasing a version of the code that had the planet orbits drawn in as lines when the solar system was fully visible.

With this and a couple of minor bugs fixed, I released the app to the market.

As is usually the way, I discovered a nasty visual bug about two minutes after I hit the save button.

The method that I used to generate the planet cutaway models was causing a horrible flicker on some devices, when viewing the planet structure, but only for the gas giant models, and only on my HTC Desire.

I hadn’t seen it when I’d done my testing as I usually do the bulk of  that on my Galaxy Tab, and the problem didn’t show up there.

As it was only a visual glitch, I decided to leave the latest app in place and find a solution, which unfortunately turned out to take a great deal of time. The problem was that the coloured rings that represent the layers inside the planet are actually a stack of coloured discs. For some reason, the renderer in my Desire couldn’t figure out which one was in front of the other, so they were constantly swapping place.

Many hours later, I realised that I’d either found a limitation in Android’s OpenGL implmentation, or a bug in Shiva. Since I was unable to create a test app to give to the Shiva team that exhibited the same problem, I decided just to do a workaround, which was to rewrite the module and generate the coloured layers as a stack of rings, rather than discs, so they wouldn’t overlap.

Sounds easy, but it’s wasn’t because I had to learn how to modify a mesh with Shiva, which isn’t particularly well documented.

The end result though looks better than the stacked disc version did, so I’m pleased, but I’d like my eight hours back.

One small step for Juno

There’s so many things that can go wrong with rockets, most of them resulting a big bang and a large insurance payout, so it was good to see that Juno got safely off the ground and into space.

Hopefully in 5 years we’ll hear that Juno arrived at it’s destination safely.

 

 

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Good luck Juno

August 02, 2011   admin   No comments

Another update for Solar Explorer, and I’ve been extra busy this time.

Apart from a minor fix, I’ve added some more planet structures for Mars and Jupiter and tweaked the update I did last week for low resolution phones.

While adding the extra detail to Jupiter, I found out that we really don’t know much at all about the almost-red-dwarf in our Solar System.

NASA is planning to launch the Juno probe to Jupiter on the 5th of August to fill in the blanks, so I decided to pre-empt the launch and put Juno into space early, in Solar Explorer.

Juno has quite an interesting design with the three solar panels making it very distinctive, though I do have to wonder why solar power was chosen since Jupiter is so far from the sun.

As usual I’ve done my best to peel the thermal foil off the spacecraft so you can see what it looks like underneath.

For a spacecraft, Juno is also a 3D modeller friendly shape, unlike Voyager and Dawn which have bits poking out everywhere. The more shapes in a model, the slower it runs on the device, so it’s a lot of hard work for me to work out what to simplify to keep the speed up while keeping the overall appearance of the spacecraft intact. It would almost be easier to accurately model the spacecraft down to the smallest detail, but then if I did that, Solar Explorer would be all but unusable on the typical device.

In a future release I plan to include labels on various parts of the spacecraft to make Solar Explorer more informative, but for now it’s enough to push ahead with more spacecraft for the full version and expanding the detail on the planets and moons.

I also see that we’re starting to get more images from Vesta. Once we’ve got it photographed from all sides, I’ll update the Vesta model to look more realistic, but it may be a little while yet before we get the full picture.

In closing, I’d like to ask NASA to do me a favour and make sure Juno gets off the ground safely, or the only space it’ll ever see will be inside my model Solar System!

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