NH at Jupiter, Planning the Jupiter encounter Options

[tasp]

The doors on LORRI and Ralph both open with one-time, spring loaded mechanisms.  These devices are well proven and have high reliability, as almost anything is better than having the door stick in the closed position, as you said. 

We will know for sure in a few months.  Does anyone know when they plan to open the doors and take test images?

I am sure there is a good reason for not doing this, but I have always wondered why these ejectable lens covers aren't made of lexan.

If they don't come off, camera would still work.

Must be missin' sumpthin' ?

[djellison]

Well - consider the MER MI cover - that's an orange filter - so even if the cover's shut, you can still see something.

I'd imagine using something like lexan or other transparant materials for a thermal cover of an instrument has potential for a lot of problems with being britle, heavier, bad thermal properties, perhaps outgassing and contaminating optics etc etc....

And as Alan's said a few times, better is the enemy of good enough.

Doug

[ljk4-1]

Jupiter wouldn't be so bright that it could burn out NH's cameras, could it?

[john_s]

Jupiter wouldn't be so bright that it could burn out NH's cameras, could it?

Nope, the New Horizons CCDs, like most CCDs, are very resistant to burnout.

[RNeuhaus]

Here is the snapshot when NH is around the closest distance from Jupiter at February 28, 2007, 05:00 am.

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

Jupiter: 2.306 millions km
IO : around 2.664 millions km Closer
Europe: 2.967 millions km
Ganymede: 3.020 millions km
Calixto: 4,160 millions km

These above predicted distance might change after the next TCM.

Rodolfo

[volcanopele]

Actually, we've just figured out that we can probably take unsaturated daytime images with our telephoto camera (LORRI), though we won't know for sure until we can do some tests in flight.  So we hope to get some nice B/W dayside images of the satellites after all.  We're still stuck with dayside saturation in our color camera, MVIC, though, so our only color images of Io will be taken in Jupiter shine, and will thus (obviously) cover only the Jupiter-facing hemisphere.

Here's a simulation of some of our best views of the four Galileans, from LORRI (highest resolution), MVIC (color, though only B/W in this simulation, and saturated on most of the daysides), and LEISA (where every pixel represents a 1.2 - 2.5 micron near-infrared spectrum).  The geometry is pretty accurate.  I've brightened up the nightside of Io so you can see what volcanos might be glowing in the dark there.

[attachment=3908:attachment]

what is the wavelength range for LORRI? Does it extend at all into the near-IR? would be interesting to see how active Pele (or Pillan 10 years after its big eruption) is when Io is in eclipse.

Remember John, there is no need to image any of the other moons, just focus on Io

[Guest_BruceMoomaw_*]

Pfaw. The most important thing NH will do at Jupiter is get near-IR spectra of the Galilean moons' surface compositions far better than any obtained by either Galileo or Cassini -- maybe good enough to settle the question of what the non-ice component of Europa's surface really is.

[john_s]

what is the wavelength range for LORRI?  Does it extend at all into the near-IR?  would be interesting to see how active Pele (or Pillan 10 years after its big eruption) is when Io is in eclipse.

Remember John, there is no need to image any of the other moons, just focus on Io 

LORRI extends to 1 micron wavelength so we may see some volcanic thermal emission on the nightside, as we will with MVIC, and with LEISA of course. We should get a nice data set on the hot spots! Plumes, too...

[ljk4-1]

LORRI extends to 1 micron wavelength so we may see some volcanic thermal emission on the nightside, as we will with MVIC, and with LEISA of course.  We should get a nice data set on the hot spots!  Plumes, too...

Can NH look for any plumes from Europa as well?

[Decepticon]

there is no need to image any of the other moons, just focus on Io 

Funny you miss spelled Europa Io

[john_s]

Maybe you folks can help us...

We're now starting to lay out the timeline for the Jupiter encounter, but what we haven't done so far is look for "Kodak moments" as the Cassini imaging folks call them- times when we have scenic alignments or unusual geometries that call for a picture that's motivated by beauty more than science. Anyone want to help us find these moments?

Mark Showalter has now updated his New Horizons ephemeris tools to include the actual spacecraft trajectory through the Jupiter system. So you can download a table of satellite positions as seen from the spacecraft, and see views from the spacecraft of any body in the system at any time. It's probably most efficient to use the "Jupiter Ephemeris Generator" tool to create a table first and use that to find possible interesting alignments (e.g. times when the RA and Dec offsets of two satellites are similar), and then use the "Jupiter Viewer" to check out the view from the spacecraft at that time. The field of view of LORRI, our greyscale telephoto camera, is 5 x 5 milliradians, or 1044 arcseconds (parameters for all instruments are here). Make sure that you are using the "Official Post-Launch" trajectory option, which is the default.

If you find a specific time when you think we should press the shutter, let us know! No guarantees that we'll be able to do so, as there are numerous conflicts and constraints, but we'll give it a try. LORRI images don't take a lot of resources so we can probably spare a few for scenic purposes. MVIC color images are more "expensive", and are likely to have partial saturation except at high phase angles, so we're less likely to use MVIC for this purpose.

Thanks!
John.

[djellison]

The very easiest way for this is if someone can get it into celestia, and we can just run thru the flyby looking for interesting moment

You've opened a big bad can of worms here John Downlink was 2048kbps from Jupiter wasnt it

I'm sure you'll have lots of loonie ideas - but a moon rising or setting from behind Jupiter with possible refraction thru the upper atmosphere could be interesting....

Not sure of exact timing (see attached) if I have the night-side-day-side right, this would see a crecent Io set behind the dark-limb of Jupiter, so it would be squished and squashed as it set, in a way a little similar to this...
http://spaceflight.nasa.gov/gallery/images.../s103e5037.html but without a bright limb of Jupiter to get 'in the way'

Some upper atmosphere refraction has been seen by Cassini...
http://ciclops.org/media/dr/2005/1114_2631_2.png
http://ciclops.org/media/dr/2005/1191_2857_2.png
http://ciclops.org/media/dr/2005/1017_2487_1.jpg

Perhaps something to be learnt about the properties and extent of the upper jovian atmosphere by catching this little event?

I think that the classic Cassini 'mutual' events of transits etc are likely to be uncommon at a range worth imaging (guessing here).

Another potential target that's perhaps half scientific, half Kodak - is a lit side of a moon, being partially occulted by the jovian ring system- not sure how it might look or if it would appear at all, but again, potential for something 'interesting' if not beautiful


Doug

Attached File(s)

 io_set_nh.mov ( 347.05K ) Number of downloads: 567

 

[hendric]

I created a spreadsheet and imported the ephermis for a few weeks around closest approach, for every 20 minutes in the enounter. Best one so far is:
MJD Objects Notes
54161.44 IO & EUROPA Really close pass

Try adding a few hundredths of a MJD either way. When using the Jupiter Viewer, enter MJD as MJD 545161.44.

There are a few others from further away. I want to redo the ephermis +- a day to closest approach to see if I am missing any due to the 20 minute step size.

I'll post the spreadsheet once I'm done, promise!

Attached thumbnail(s)

 

[hendric]

OK, so there were a few additional close Io and Amalthea passes. Looking at the graphs, the majority of passes are Io & Amalthea, with a few others, mostly with Amalthea. The speedy little moon gets around!

MJD Bodies Comments
54149.68056 IO & AMALTHEA Europa is just out of view to the NW, good view of the rings
54149.8888 IO & AMALTHEA Thebe is left of Amalthea, IO is pretty far away
54150.98611 IO & EUROPA Far pass
54157.925 IO & JUPITER Io grazes the north side of jupiter, leaving J disk on dark side
54158.943 IO & JUPITER Io goes behind jupiter on the dark side
54159.365 EUROPA & JUPITER Europa grazes the southern dark side of Jupiter
54160.12 IO & JUPITER Crescent IO in front of dark side Jupiter, emerges few minutes later
54160.12 AMALTHEA & JUPITER Crescent Amalthea in front of dark side of Jupiter, emerges a few minutes later
54161.042 IO & JUPITER Io disappers behind jupiter on the dark side, with the rings visible and in shadow. Encounter with Io and Rings starts earlier
54161.43646 IO & EUROPA Really close pass!!!
54161.85 EUROPA & AMALTHEA Rings are between them
54161.97083 IO & AMALTHEA Rings are between them, with Adrastea possible
54162.85365 IO & AMALTHEA Close pass, rings and Metis visible, long encounter!
54165.125 IO & EUROPA Small crescents for both
54165.70833 IO & AMALTHEA Rings & jupiter, but distance function shows a bump, so could be interesting encounter
54168.70833 IO & EUROPA Pretty far pass, but in the same field
54170.94633 IO & EUROPA Amalthea emerges from behind Jupiter, might make an interesting appearance, all objects showing thin crescents

I had to do a manual search for Jupiter events, and gave up after a bit.

Unfortunately, the spreadsheet is over 20 MB, so I can't post the full thing. Here is a PDF of the charts, and a cut-down spreadsheet that you can enter the data in yourself. Some notes:

1. You have to modify the RA so that it is monotonic. What does that mean? When scrolling down, if you get to a set of entries that go from +~24 to ~0, then you need to change the RA(corr) column to (RA+24) to keep it linear.
2. RA is multiplied by 15, to get something vaguely representing degrees.

Any other questions, or if you want the full spreadsheet, feel free to ask.

Attached File(s)

 ephem_jup_5946.pdf ( 868.6K ) Number of downloads: 728

 

[hendric]

Here's the reduced spreadsheet.

Attached File(s)

 cut_down_ephem_jup_5946.zip ( 155.31K ) Number of downloads: 539