PFS issue on Venus Express, PFS scanner stuck in its closed position Options

[centsworth_II]

...that falls into the "bait and switch" category.

Yes, but could or would NASA ask to have another instrument added? I recall reading in "Roving Mars" that Steve Squyres et al were only planning on one rover and NASA asked them to build two.

[ljk4-1]

If someone could clarify for me: What could be done from Earth
to make up for the PFS?

[Guest_DonPMitchell_*]

If someone could clarify for me: What could be done from Earth
to make up for the PFS?

I think they were hoping to correlate PFS read readings with cloud pictures, to get a better idea of what the mysterious UV-darkening substance is, and also perhaps why the cold collar is different (it appears to be a higher-altitude white haze layer). That's not easy from Earth. In general, the confusion of the Earth's atmosphere has made precise spectroscopy of other planets very difficult. In the case of Venus, there were decades of different scientists publishing, "There's water", "No there isn't", "Yes there is, and we see oxygen too!", "I don't!"...

[ljk4-1]

I think they were hoping to correlate PFS read readings with cloud pictures, to get a better idea of what the mysterious UV-darkening substance is, and also perhaps why the cold collar is different (it appears to be a higher-altitude white haze layer). That's not easy from Earth. In general, the confusion of the Earth's atmosphere has made precise spectroscopy of other planets very difficult. In the case of Venus, there were decades of different scientists publishing, "There's water", "No there isn't", "Yes there is, and we see oxygen too!", "I don't!"...

Hmm... how about a telescope in Earth orbit that could examine Venus
for those features?

[JRehling]

Hmm... how about a telescope in Earth orbit that could examine Venus
for those features?

I think the problem is the high spatial resolution that's desired. Imaging spectrometers (like VIMS on Cassini) need to be up-close to get the spatial resolution. If you're summing over a big parcel of the cloudtop area, you don't find out what distinguishes the darker clouds from the lighter ones.

It seems to me that Messenger, of all unexpected calvaries, should actually perform some pretty significant science in this regard, but it's a one-flyby shot. But assuming the weather patterns on Venus tend to be similar from one month to the next (shouldn't be any seasons at all), one snapshot in time might be 80% as good as the same thing repeated for a year of orbiter data.

[Guest_DonPMitchell_*]

FYI, here is the hubble photo of Venus. I dug up the original image, because I wanted to see what was really there before someone produced the ugly purple-colored over-sharpened image that gets published all the time:

[attachment=6082:attachment]

This is enlarged 4 times with a windowed sinc filter, and it's taken with a UV filter.

[The Messenger]

Notta about the PFS in the latest ESA press release. No news is good news?

[ustrax]

Notta about the PFS in the latest ESA press release. No news is good news?

"PFS -
The instrument is currently OFF and is not included in the routine planning. Any further attempt to move the scanner is now suspended until further notice."

Here you have more regular updates on the operations.

Link edited

[Rakhir]

Current planning does not forsee any PFS testing until early end September/early October 2006.

http://sci.esa.int/science-e/www/object/in...fobjectid=39710

[PhilHorzempa]

I have it, from a Brilliant Reliable Unmanned Craft Expert,
that the PFS on Venus Express may still be "cured."
Since ESA tests indicate that warming the PFS up
seems to help, they may be considering the possibilities of a more intense
thermal shock. This would mean exposing that side of VEX to the Sun in
a major way to heat up the PFS a lot more, but doing careful studies
to make sure that they won't damage the other instruments in the process,
and also making a lot of high-priority science observations with them
before risking this type of maneuver.
They may also try cycling it between strong heat and
strong cold. Sometimes such thermal shock works, as with
MARSIS' antenna, and sometimes it doesn't, as with
the forward plasma-analyzer door on Mariner 10.
The other option would be to try to include a replacement on Japan's Venus
probe.


Another Phil

[Guest_AlexBlackwell_*]

PFS is still off according to the latest VEx update.

BTW, VEx will be the subject of a special issue of an upcoming issue of Planetary and Space Science. I don't think these will be science results, but rather pre-launch science papers.

[JRehling]

Messenger will fly by Venus in six weeks. Does anyone have any information about possible coordinated observations?

[Guest_AlexBlackwell_*]

Messenger will fly by Venus in six weeks. Does anyone have any information about possible coordinated observations?

I think I mentioned something about this late last year.

[JRehling]

I think I mentioned something about this late last year.

Right -- I simply misplaced in my memory which encounter would be the "blind" one and which one would be the science one. Delayed gratification again...

[stevesliva]

They may also try cycling it between strong heat and strong cold. Sometimes such thermal shock works, as with MARSIS' antenna, and sometimes it doesn't, as with the forward plasma-analyzer door on Mariner 10.

It worked with the Stardust navcam, after outgassing contaminated the lens.