MEX VMC - Back on, and online! Options

[djellison]

I heard about this 24 hours ago, and couldn't believe it - this is EXACTLY what has been missing from ESA. MASSIVE kudos to the ESOC MEX flight ops team for doing it

http://www.esa.int/SPECIALS/VMC/index.html

The last time I wrote a post and hit 'submit' at UMSF with a smile this big on my face, was when Oppy successfully got out of Purgatory.

[ormstont]

...it seems the images are in two sections: a ~1hr period near apocenter, and another ~1hr period near pericenter....I'm assuming operations (downlink etc.) and other instruments prevent this from being done

Yep, you're right there - it's mainly instrument operations that constrain us to those windows. Aspera, a Swedish experiment looking into space plasma and energetic atoms aims to be on permanently to get a good dataset. However, every 3-4 orbits (~once per day) we have to perform a reaction wheel offloading and orbit maintenance, which means firing the thrusters. When we do this Aspera shuts down for an hour because the thruster plumes would interfere with their measurements. This thruster activity is always placed right after apocentre for maximum activity and that gives us our ~1 hour VMC window. Sometimes though these are impacted as you say by ground station passes a that's why we get our average frequency of 2-3 obs per week.

The VMC obs just after pericentre are much rarer and happen when we perform a orbit change, here we have to fire the thrusters to achieve this but the point of highest efficiency is at pericentre. Therefore Aspera shuts down and we get a relatively low-altitude VMC observation (assuming Flight Dynamics don't choose that period to obtain tracking data from the burn).

one VMC image every ~5 minutes for one full orbit would make for one amazing animation.

You're very very right here too (you could come work for us!), we'd all love to do a full orbit animation! As this would require agreement from all the other instruments though it will require quite some negotiation. I'm constantly on the look-out for chances though, but don't want to impact our prime science mission. The other slight problem is that the VMC packet store (like a directory on a computer) is limited to 60 images, so we'd have to ask nicely for another instrument to lend us their packet store

Color me embarrassed.

Lol....we all get embarrassed - how do you think we felt when we got our first VMC images and they looked like this: http://www.esa.int/SPECIALS/VMC/SEM4SJEVL2F_1.html#subhead4 ?! At least it makes for a cute story in the history of VMC I'll ask Daniel to update the captions for your images on the website. Even if they're of a slightly different location they're still great work!