Mro On Approach, TCM-3 not required Options

[djellison]

Is it just me - or is there some great documentation listed....but not accesable Sort of a wave-candy-infront-of-baby type thing

Doug

[Bob Shaw]

Hmmm... ...perhaps it's time to mention the old space-dog's proverb:

Go low, you glow!

Bob Shaw

[Guest_AlexBlackwell_*]

Is it just me - or is there some great documentation listed....but not accesable Sort of a wave-candy-infront-of-baby type thing

Sorry about that, Doug. I thought only the second "Documentation" link was reserved for team access (i.e., requires a userid and password). It looks as if the first tree is as well.

[jmknapp]

I generated a view of Earth as MRO comes out of occultation on March 10th, based on the "ideal" NAIF kernel:



The above is in spacecraft time not accounting for speed of light. The signal would get to Earth 11 minutes, 58 seconds later, at 22:16:00 UTC (5:16pm EST) .

[Bob Shaw]

I generated a view of Earth as MRO comes out of occultation on March 10th, based on the "ideal" NAIF kernel:


The above is in spacecraft time not accounting for speed of light. The signal would get to Earth 11 minutes, 58 seconds later, at 22:16:00 UTC (5:16pm EST) .

Now, if only that could be photographed during the aerobraking test image campaign...

Bob Shaw

[ugordan]

Now, if only that could be photographed during the aerobraking test image campaign...

Not to mention there haven't been all that many cameras with a 0.005 degree FOV flown on planetary missions...

[djellison]

Not to mention there haven't been all that many cameras with a 0.005 degree FOV flown on planetary missions...

http://hirise.lpl.arizona.edu/HiRISE/image...rise_params.gif
1.14 degrees for HiRISE - which is just a tiny bit more than this much

http://space.jpl.nasa.gov/cgi-bin/wspace?t...orbs=1&showsc=1

Doug

[jmknapp]

1.14 degrees for HiRISE - which is just a tiny bit more than this much

Even so, at HiRISE resolution of 1 urad/pixel, Earth being 59 urad (0.0033 deg) across would be ~59 pixels.

Approximately this resolution (blown up to 512 pixels across):



On the Earthrise time for the HGA, I don't suppose that the Mars atmosphere affects the X-band very much?

[ugordan]

On the Earthrise time for the HGA, I don't suppose that the Mars atmosphere affects the X-band very much?

The effect is probably negligible, even more so due to the fact Mars' atmosphere contains virtually no vater wapor.
The above simulated image would in reality be suspended in a thick reddish tint due to the atmosphere, and the whole Earthrise would have to be very carefully timed even if one knew the precise orbit MRO has -- which obviously won't be the case due to varying performance of the engines during MOI. In short, aiming for this KODAKMMT would be very, very hard and the end result wouldn't be all that rewarding.

[djellison]

I think I'd rather have the "OMFG thank god for that" moment of the earliest possible HGA signal back on earth suggesting a good burn than the kodak moment to be honest.

MGS did take an Earth and Jupiter image some time ago - perhaps in an extended mission, HiRISE could 'do' earth as well, but in the meantime, I want it looking down

Doug

[ugordan]

I think I'd rather have the "OMFG thank god for that" moment of the earliest possible HGA signal back on earth suggesting a good burn than the kodak moment to be honest.

Err... surely you mean the latest possible signal back, meaning a better-than-expected burn? The earliest would be if no MOI occured and that would kinda suck, wouldn't it?

[djellison]

i.e. earlier than if the spacecraft was orientated to take an image during the egress from behind Mars and then had to reorientate for HGA pointing to Earth.

And there's such as thing as the burn being too long - more is not better - it would mean too much fuel useage and thus lost potential for maintaining the lower science orbit.

Doug

[ugordan]

i.e. earlier than if the spacecraft was orientated to take an image during the egress from behind Mars and then had to reorientate for HGA pointing to Earth.

Oh, I see. Good point.

And there's such as thing as the burn being too long

True, true! But a slightly better than nominal burn would conceivably reduce the time required for aerobraking. That is, if a slightly less agressive aerobraking strategy isn't selected in that case.

EDIT: Is it me, or is the updated forum SW acting kinda funny sometimes w/ regards to quotes?

This post has been edited by djellison: Mar 1 2006, 04:35 PM

[djellison]

EDIT: Is it me, or is the updated forum SW acting kinda funny sometimes w/ regards to quotes?

No - it's not just you - I'm looking into it - but edited your post manually to sort it out in the mean time

Doug

[helvick]

In short, aiming for this KODAKMMT would be very, very hard and the end result wouldn't be all that rewarding.

Probably true for this shot but I reckon that a shot of Earthrise over the Martian atmosphere that had this sort of resolution would be a stunningly evocotave picture.