[X] My Assistant

[elakdawalla]

I am building some web pages about MRO (we're hosting the team website for Mars Climate Sounder) and am looking for a tool that I can use to draw some pictures of the shapes of orbits and ground tracks. I know that there are fancy tools out there, like SOAP, but I am hoping that there are some tools out there that are a little easier to use that I can use to generate some simple diagrams. For instance, I'd like to create one diagram on a flat map projection (simple, mercator, whatever) that shows the 17-day ground track repeat for MRO, and one with Mars as a sphere showing the position of the near-polar orbit, maybe one comparing the orbits of MRO, MGS, and Odyssey, even maybe generate a bunch of diagrams to make an animation showing how as MRO goes around Mars its orbit is sun-synchronous. I know I could do all of this with SOAP but I was never able to use SOAP without a lot of hand-holding from a very patient person at JPL. I would appreciate any advice or help on simpler tools to visualize orbits at Mars!

--Emily

[elakdawalla]

Thanks for the comments and suggestions. Looks like I may have to try pounding my forehead against SOAP to get what I want.

--Emily

[mcaplinger]

Looks like I may have to try pounding my forehead against SOAP to get what I want.

I looked around but it looks like Aerospace Corp has continued to make it difficult to get SOAP, and I don't have a copy here, or I would try to help you out.

For the groundtrack walk, I could crank something with our targeting software.

I installed Celestia and it's not too bad, but for the fact that it only processes Keplerian orbital elements, which for spacecraft will stay accurate for a few days at best. And translating Mars orbits to the right coordinate system will be a somewhat painful bit of tedium (if you recognize the phrase "IAU vector and equinox of epoch", you know what I mean).

Here's an example of what Celestia shows for MGS and Odyssey. It's pretty, but the positions (based on some config files I found on the net) are fiction. And Celestia appears to save JPEGs flipped left-for-right. Oh well, so close!

[helvick]

Here's an example of what Celestia shows for MGS and Odyssey. It's pretty, but the positions (based on some config files I found on the net) are fiction. And Celestia appears to save JPEGs flipped left-for-right. Oh well, so close!

Celestia shouldn't be that far off on the instantaneous locations of the spacecraft\solar bodies provided you are using accurate spacecraft xyz files but the orbital tracks have been an issue IIRC. There was a problem at one time with the texture maps for Mars where the default Mars surface texture was 180deg out of line with reality - that was in a fairly early version so it shouldn't be a problem with anything recent. I've never seen the inverted jpeg problem before - spooky.

[mcaplinger]

Celestia shouldn't be that far off on the instantaneous locations of the spacecraft\solar bodies provided you are using accurate spacecraft xyz files...

No, wait a minute, you're right. I was assuming that the only way to put the orbit into Celestia was to supply orbital elements. I now see that there's an option to use "SampledOrbits" which are just the XYZ locations at some time spacing. Assuming that Celestia wouldn't choke with, say, a few months' worth of 5-minute or 1-minute spacing, one could write a program to extract that from the SPICE files. Then there's just the wrinkle of figuring out the coodinate system.