A.A.T.L.A.S. Short Film

[*Aqua*]

"hurry up and get there"

I didn't do calculations but wouldn't it be faster to use a propulsion system with a fast acceleration instead of one with a higher top speed? I mean a chemical rocket can accelerate to high speeds within minutes or hours while an ion engine needs months or years to do the same.

For example the New Horizons probe which is on its way to Pluto traversed Saturn's orbit after about 2.3 or 2.4 years after launch. That isn't far from your projected 2.2 years of your ion probe. If they used a bigger rocket New Horizons would have been even faster.

I don't mean to come across as "snotty" if I am. I enjoy the questions and feedback, I'm just backing up the technical stuff as best I can with my understanding of all this crazy science and math.

It's ok. I didn't feel offended.

[-ctn-]

New Horizons was already launched on the fastest rocket we have available.

While you are right, I could switch it to a chemical rocket like the Atlas V - that would still cost more than the ion engine and it would still need more deltaV than is capable from that rocket.

Plus ion engines are cool, are they not?!

[-ctn-]

UPDATE:

We've ordered the bulk of the parts needed to build the first rover. While we don't have everything coming, we have enough to keep us busy for the coming few weeks until we learn how to program the little guy with Arduino and get it... Roving.

This will be a sojourner-sized rover, wirelessly controlled using the Arduino programming language for maximum control.

I'm really excited for this! I've read several books about the building of the different Mars rovers, so it feels like on some level, I'm part of the JPL team. I get to program and build it and hopefully sell the idea to a few investors, which will help purchase the parts to finish it up and build the second rover.

[Streetwind]

Have you considered using the solar panels as heat radiators instead, and assume an onboard nuclear reactor? It would produce much more than 3.4 kW (which is less than what the Dawn probe can output today with its giant solar wings at 1 AU!). A device like NASA's experimental SAFE-400 reactor is fully closed cycle, weighs only half a ton, is the size of a box you could hold in your arms (if it didn't weigh half a ton..) and produces 100 kW of usable electricity for years at a time, with 300 kW waste heat to be radiated. With a little sci-fi handwaving in a futuristic setting, you could get even better output (or an even smaller/lighter reactor).

This would make the high-thrust ion drive much more believable, because you simply have that much more energy to throw at the problem! You could also continue to use the ion drive for the Saturn insertion burns, which is probably recommended... because you're flying a greatly accelerated trajectory. Look at the New Horizons probe: it's going slower than your Titan mission, and yet it is still a far cry from being able to slow down at Pluto. It would need a five digit amount of dV to do so. It cannot hope to produce this dV with a chemical propulsion system, which is why New Horizons is just doing a flyby; and neither can your Titan mission. It absolutely needs that ion drive to brake. (Says my gut instinct from having done a number of high energy transfers in KSP, but without actually running the numbers on yours.)

Downside, of course: heat radiators aren't gonna be reflecting so beautifully... but on the other hand, they can have an awesome red glow

Edited April 17, 2015 by Streetwind

[-ctn-]

We received most of the parts to build one of the rovers today! With some modification, lots of work, and some luck, we'll have a functioning rover within a few weeks.

[-ctn-]

Well the rover thing has been a huge headache and nightmare so far.

Instead, I've been using Unity to create a 3D enviornment, as close as I can via radar images, to the area the film takes place. This 3D map will be used as the main reference for animatics (moving storyboards) and the cgi / miniature background plates.

[tater]

Solar panels? At Saturn? RTGs. (I found the page 2 stating they were only for a transfer burn, but it needs power to transmit as well.)

Edited June 30, 2015 by tater

[-ctn-]

Well, by my calculations, these solar panels would still generate a around 200 watts out at Saturn.

I'll see if I can come up with a design using RTG or nuclear power that I like as much as these solar panels. I kind of like the aforementioned idea of making them radiator panels that glow red.

- - - Updated - - -

Scratch that, I'm definitely using old and very wrong scribbled data. I think a more accurate wattage by Saturn would be around 16 watts.

EDIT: But there is an RTG on the micro rover, which produces around 60 watts of electric power. So you could theorize that the rovers onboard computer and antenna is what contacts earth periodically and the solar panels are wholly dedicated to running the ion engine for the transfer burn.

Edited July 1, 2015 by -ctn-

[*Aqua*]

200 watts at Saturn means the solar panels will generate about 20 kW at Earth. Current solar panels can generate about 220 W/m² near Earth. So your solar panels must have an area of about 91 m².

If you still use the panels you've shown in post #10, then each panel consists of 6 cells while I estimate the smaller one of about 1/3 the size of the larger one (but it's difficult so see, could be something different). So you have about 4 * (6 + 1/3) = 25 1/3 units of panel area. Using the W/m² number from before 1 unit of panel area equals about 91 / 25.3 = 3.6 m².

One cell of the bigger solar panels seems to have a height-width ratio of about 1/2. Therefore the height must be SQRT(3.6 m² * 1/2) = 1,6 m. So the whole length of one big solar panel on your probe is ~9.6 m. Is that right?

Edit: Ninja'd.

Edited July 1, 2015 by *Aqua*

[-ctn-]

So after seeing BB-8 from the new Star Wars movie all over the place, the idea hit me that a similar, spherical design could work for rovers on a low-gravity body.

I've been trying to design a believable and interesting looking sphere-bot, and I have a couple of ideas that may work but I'm still trying to catch all the issues.

So far it seems like a much better option than a typical wheeled rover. Here's some of the pros-

Using a tiny RTG (600 grams), the rover has enough electricity to roll around and use the camera and computer, and the rest of the thermal energy goes to heating the inside of the rover. Due to heat loss through the shell of the sphere, literally ALL of the thermal energy from the RTG goes to heating, which would heat the inside of the sphere to 0 degrees Celsius. There's no need to stick the RTG on the outside or use "oven mitts" to catch the heat.

The wheels and other moving parts are located inside the nice, warm sphere - so there's no worry of the cold breaking the moving parts or them getting gunked up with material (which is a big deal on Titan, I'd imagine).

The only issues I have with it are A) it probably wouldn't be able to scale steep terrain and instead would just roll down large hills or dunes (which may be wrong, low gravity would probably help with that or it could also make for a quick funny scene of it tumbling down a dune)

And how do you attach instruments to it? I have two different designs right now, and one works better with movement but it would only work as an optical probe which is pretty unacceptable. The other design works for all the science instruments but may not work mobility-wise.

[vger]

The wheels and other moving parts are located inside the nice, warm sphere - so there's no worry of the cold breaking the moving parts or them getting gunked up with material (which is a big deal on Titan, I'd imagine).

The only issues I have with it are A) it probably wouldn't be able to scale steep terrain and instead would just roll down large hills or dunes (which may be wrong, low gravity would probably help with that or it could also make for a quick funny scene of it tumbling down a dune)

And how do you attach instruments to it? I have two different designs right now, and one works better with movement but it would only work as an optical probe which is pretty unacceptable. The other design works for all the science instruments but may not work mobility-wise.

So you're talking about a "hamster in a ball" kind of robot?

My biggest concern, even more than instruments, is what to do with the solar panels. The rover, if we can even call it that anymore, would need to be able to store enough power to move around, only flipping out the solar panels when it's stationary.

The only other thing I can think of is, why make it a sphere? Why not something more like a tire with struts on both sides? Sorry I don't have an image to provide with this, in case my description just has people scratching their heads.

With the struts, the rover could move with the solar panels deployed. If they were allowed to swivel with the proper center of mass, gravity alone could keep the panels pointing skyward. You can also have apertures on both sides of the 'tire' that open a little wider to allow instruments to come outside, parallel with the struts. The probe could extend 'kick stands' out of these openings as well if it needs extra stability for precision jobs.

How will it turn? With a torus shape, simply shifting its center of mass to the left or right slightly will cause a natural turn. Smaller wheels at the end of the struts can prevent it from completely tipping over and becoming helpless.

This is an INSANELY complex idea though and seems more risky than any space agency would be apt to consider.

[-ctn-]

Yes, essentially a hamster in a ball.

Remember the rover itself is powered solely by RTG, solar panels are useless on Titan. So there is no issue with power generation.

Being a sphere shape, any movement would be "right side up" if the inside was stabilized by gyroscope.

The other idea I had was continuing the basic sphere shape, but if you cut a sphere in half and each hemisphere is a "wheel." Sandwiched between the wheels is a gyroscope stablizied center portion that contains all the instruments and RTG. If it fell on its "side," in theory, the spinning "wheel" it fell on could create enough torque to right itself.

Kind of like this:

But the middle part wouldn't rotate with the two hemisphere "wheels."

[Mad Rocket Scientist]

Just wanted to update, still working on the design and look of the Cruise stage. It's unclear at this point whether the actual model will be a miniature shot against a greenscreen or a CGI model.

http://img.photobucket.com/albums/v68/MoviesColin/Mobile%20Uploads/image.jpg

http://img.photobucket.com/albums/v68/MoviesColin/Mobile%20Uploads/image-1.jpg

This is kind of late, and you might have already decided, but I would like to vote for miniatures.

Edited October 25, 2015 by Mad Rocket Scientist

[-ctn-]

This is kind of late, and you have already decided, but I would like to vote for miniatures.

I definitely agree. The plan is to use 1/6 miniatures for the cruise stage in space and use a full size version of the lander stage for the EDL sequence.

The 3D models help with the design and layout process and could potentially be 3D printed for the miniatures.

[Mad Rocket Scientist]

I definitely agree. The plan is to use 1/6 miniatures for the cruise stage in space and use a full size version of the lander stage for the EDL sequence.

The 3D models help with the design and layout process and could potentially be 3D printed for the miniatures.

Great! I can't wait to see it!

- - - Updated - - -

I definitely agree. The plan is to use 1/6 miniatures for the cruise stage in space and use a full size version of the lander stage for the EDL sequence.

The 3D models help with the design and layout process and could potentially be 3D printed for the miniatures.

Great! I can't wait to see it!

- - - Updated - - -

I definitely agree. The plan is to use 1/6 miniatures for the cruise stage in space and use a full size version of the lander stage for the EDL sequence.

The 3D models help with the design and layout process and could potentially be 3D printed for the miniatures.

Great! I can't wait to see it!

[-ctn-]

For anyone following this thread, the short film has been shelved indefinitely. We are pursuing a different script (still a space-y short film) but this project proved to be a little too difficult/ambitious. Unfortunately, despite all of my efforts, I couldn't find a single local crew member to help produce it or help develop it.

I will be creating a new thread for the different short film when we have the schedule set /facebook page going and the kickstarter campaign is rolling.