LAMO, aka Low Altitude Mapping Orbit Options

[dilo]

I think is time to start this new topic, now that Dawn is more than half-way in the transition from HAMO to LAMO (as showed in the plot below).

Attached thumbnail(s)

 

[ElkGroveDan]

Good thing we aren't calling it a "Low Mapping Altitude Orbit."

I get the feeling that many more surprises await us in finer detail as the surface resolution improves.

[dilo]

Another way to show the progress from HAMO to LAMO is the following updated plot where points colors reflects engine status:

I tried to interpolate average height with a blue line. Time gaps are due in part to me (not continuous monitor) and in part to Mystic simulator black-outs.

EDIT: plot updated to Nov,15

[dilo]

And finally, we are below 300km height... not far from final target!

[Phil Stooke]

Hopefully the daily image releases will resume shortly!

Phil

[stevesliva]

Hopefully the daily image releases will resume shortly!

You mean images rather than other data products? Or images specifically from LAMO?

Pace hasn't slackened... now here:
http://dawn.jpl.nasa.gov/multimedia/imageo...h=2011-November

Last two were HAMO images, though.

[Tunglere]

Images from Nov. 10-13 don't currently show up on the Dawn Image of the Day page (November), but they do show up on Photojournal.

[Phil Stooke]

The latest four images were posted on the same day... I check every day, believe me. We had a minibreak. But these are spectacular!

Phil

[dilo]

Updated situation, all plots:

Engines are now silent and average height is around 270 km...

[dilo]

Now that we have an improved simulator (better Vesta digital model and, especially, more frequent screen updates) I am frequently monitoring the simulated height of the probe; in the last 24 hours, engines were off but orbit isn't completely stable:

The interpolated sinusoidal curve correspond to a 5.1 hours average period between 235 and 285 km height. The reason of slight phase/amplitude variations sould be the irregular gravity field of Vesta. In fact, as explained in the last Mission Status, the purpose of these thrust stops is a natural or passive orbit adjustment (especially the orientation).

Edit: slightly modified previous text and updated plot (no orbit decay)

[dilo]

New update after two long simulator black-outs:

Based on today's status report, "The spacecraft thrusts occasionally with its ion propulsion system, but most of the time it coasts, letting Vesta's gravity reorient its orbit."
Note also that last two published images were taken 15 days ago from an intermediate distance of 480km:
http://dawn.jpl.nasa.gov/multimedia/imageo...p?date=20111123 http://dawn.jpl.nasa.gov/multimedia/imageo...p?date=20111122

[dilo]

Further update:

Dawn is almost there!

[dilo]

Now short engine burns are frequent:

[Phil Stooke]

"Dawn image EDR data will be publicly released to the science community by the PDS within 90 days after each acquisition phase. Therefore, raw Vesta approach images will be available in November 2011. Raw images for other acquisition phases including survey, high altitude (HAMO) and low altitude (LAMO) mapping orbits will be delivered throughout 2012"

"However, radiometrically calibrated PDS images (RDRs) will be publicly released six months after Vesta departure"

... from Jeffery Anderson's AGU poster abstract.

Exciting!

Phil

[elakdawalla]

Time for us to lurk on the Small Bodies Node website.....that is where they'll likely be hosted, right?