I was going to post this tomorrow morning, but since it's too cloudy to see mars tonight (1AM at the moment...) I decided i'd do it now...! Damn clouds...
Anyway... I've added a Mariner 2 xyz and model to the spacecraft page on my site http://homepage.eircom.net/~jackcelestia/
The model was simple enough, but the trajectory is a WHOLE different story... Originally, I got it off the NSSDC's COHOweb site. However, it was there only in HGI (Heliographic inertial coordinates) which means that it's offset 7.25 degrees to the eclipic (latitude), and 75.5 degrees longitude. (in other words, the reference frame is the sun, not the ecliptic). SO... I had to come up with a way to tilt the entire thing 7.25 degrees. It sounds simple, but after 2 long attempts over about 3 weeks, I got a result that looked like a bicycle wheel that got crushed by a truck. Great.
Then I got in contact with one of my contacts at the NSSDC, (which I probably should have done at the very start...) to see if I could get any formulae from him which could fix the problem for me... After trying a few different ways over about another week & a half, today I finally cracked what was going wrong. Success! All I needed to do was convert the Z (up-down) value into ecliptic, using a formula from the NSSDC, and use the HGI latitude & distance unchanged (apart from a simple 75.5 degree rotation!)
Mariner 2 is only the first of a good few other craft that I can now add in to celestia with relatively accurate xyz trajectories! (like Pioneers 6 & 9, and Zond 3, to name a few...)
Anyway, i'm rambling...
Mariner 2 was NASA's first Venus probe (Mariner 1 failed after launch), and the World's first to encounter another planet, and still be functioning at the time of the flyby (flyby distance was 34,773km). The USSR had previously flown by Venus with dead probes. It didn't carry any cameras, but with it's Radiometers and other instruments:
The NSSDC site wrote:Scientific discoveries made by Mariner 2 included a slow retrograde rotation rate for Venus, hot surface temperatures and high surface pressures, a predominantly carbon dioxide atmosphere, continuous cloud cover with a top altitude of about 60 km, and no detectable magnetic field. It was also shown that in interplanetary space the solar wind streams continuously and the cosmic dust density is much lower than the near-Earth region. Improved estimates of Venus' mass and the value of the astronomical unit were made
It was also (I think) the first spacecraft to survive a hit from a small object, while in Heliocentric orbit. Something knocked it off target on the 8th September 1962, but attitude was quickly restored by it's gyros.
So... Here's what I know you're all waiting for- SCREENSHOTS!!
Enjoy!
