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

[The Messenger]

Well its not like the public are ever going to get to see data from Venus Express (judging from ESA's terrible record so far) only a handful of scientists working on the mission will see that..... so from th publics (and us) perspective it probably doesnt matter what does and doesnt work.

Its not quite that bad - they often trumpet new discoveries (I expect we will hear soon that they have discovered that Venus has an atmosphere).

In any case, we have a thread for this kind of venting:

http://www.unmannedspaceflight.com/index.p...=60&#entry51717

Feel free to indulge there.

It is interesting, that in the status logs, they have simply been stating that the PFS is 'off line', the same as other instruments.

[Guest_DonPMitchell_*]

It is bad news. The Fourier spectrometer was very important. Does anyone know how its characteristics compare to the Venera-15 FS?

With regard to ESA data, they have an official site where science data is supposed to be publically posted, like NASA's PDS system: Planetary Data Archive.

Let me know if you can find any actual data there ("Have you in fact got any cheese here at all?").

[djellison]

"Have you in fact got any cheese here at all?"

Another member shows his true colours..

"Well, I'm sorry, buy I'm going to have to shoot you"
"Right'O Sir"



Doug

[dvandorn]

("Have you in fact got any cheese here at all?").

Not... as such, sir, no.

-the other Doug

[The Messenger]

It is bad news. The Fourier spectrometer was very important. Does anyone know how its characteristics compare to the Venera-15 FS?

With regard to ESA data, they have an official site where science data is supposed to be publically posted, like NASA's PDS system: Planetary Data Archive.

Let me know if you can find any actual data there ("Have you in fact got any cheese here at all?").

Sure:

Æ
0ý„·ý*$
]„·ýa$$ Æ
0ý„„y„2& *$
+D‚.„x/„ða$ $ Æ
A#*$
@&a$ $ Æ
A#*$
a$ ) * + I i n € ‚ £ ¤ § ¨ « ¬ ¯ ° ³ ´ · ¸ » ¼ ¿ À Ã Ä Ç È Ë Ì Ï Ð Ó Ô × Ø Ý Þ ß à ë í       " # & ' * + . / 2 3 6 7 : ; > ? B C ôêÞêôêÕËÆ»·Ë·Ë·Ë·Ë·Ë·Ë·Ë·Ë·Ë·Ë·Ë·Ë·Ë·­

And this is copied from the "Entry point to understand the contents of the PFS data sets"

[Bob Shaw]

Sure:
And this is copied from the "Entry point to understand the contents of the PFS data sets"

It's a secret! If you are to be given the data, then first you must be killed...

Bob Shaw

[Guest_BruceMoomaw_*]

Tentative good news on the PFS mirror front from "New Scientist" ( http://www.newscientistspace.com/article/d...spacecraft.html ): Vittorio Formisano announced that on April 27 they moved the mirror not "a tiny amount" as we'd heard before, but fully 30 degrees. "Formisano... told New Scientist he hopes the team will be able to rotate the mirror 90° as early as this week, putting it in a usable position." This would seem to suggest that warming it up is indeed loosening the jam, as the PFS team originally thought.

[Guest_BruceMoomaw_*]

Glum news on the subject from the May 22 Aviation Week: "ESA engineers will decide at the end of July, at a final commission review, whether they can recover full use of a scanning mirror on the PFS spectrometer...Tests following the probe's arrival into final orbit around the planet on May 9 showed the mirror to be blocked at the calibration point, and hopes that the changing temperature regime might release it have not materialized. However, engineers say there is enough overlap among the probe's instruments to minimize data loss."

That last is the usual sour-grapes language we hear in such cases. PFS was one of the two key instruments on VeX -- it was not regarded as worth funding without both of them, and it and VIRTIS were supposed to work simultaneously to help make each other's atmospheric measurements comprehensible. This is a very serious loss.

[ljk4-1]

Any chance they could use the probe's thrusters to shake up
the craft enuogh to perhaps loosen the blockage?

I know, it didn't work any better for Galileo's stuck antenna,
but in lieu of sending a repair crew to Venus....

[Guest_DonPMitchell_*]

That last is the usual sour-grapes language we hear in such cases. PFS was one of the two key instruments on VeX -- it was not regarded as worth funding without both of them, and it and VIRTIS were supposed to work simultaneously to help make each other's atmospheric measurements comprehensible. This is a very serious loss.

I agree, this is a very bad news. VEX will tell us nothing about the composition of the Venusian clouds without the Fourier spectrometer. Let's hope that VIRTIS will at least reveal some new clues to the circulation of the clouds and atmosphere. Maybe we will be surprised by VMC also, but it seems like a rather crude camera.

[gpurcell]

I sense PFS Discovery proposal memos being generated by researchers as we speak....

[Guest_BruceMoomaw_*]

It might be possible to add such a spectrometer to (say) Bruce Campbell's "VISTA" Venus radar orbiter -- but the trouble is that the proposals for the next Discovery mission are, I believe, already past due. Certainly we have here further proof that the enduring bane of spacecraft is moving parts, and that more attention should be paid to this problem.

[gpurcell]

It might be possible to add such a spectrometer to (say) Bruce Campbell's "VISTA" Venus radar orbiter -- but the trouble is that the proposals for the next Discovery mission are, I believe, already past due. Certainly we have here further proof that the enduring bane of spacecraft is moving parts, and that more attention should be paid to this problem.

Bruce, would the procurement rules for Discovery allow a PI to add capacity to a mission if it is selected as a candidate for further study?

[JRehling]

Messenger has two spectrometers and is making a flyby of Venus. Atmospheres are better mixed than surfaces: one great flyby might do a lot of the good as far as composition goes.

Solomon et al [2006] says of the flyby: <<MDIS will image the nightside in near-infrared bands, and color and higher-resolution monochrome mosaics will be made of both the approaching and departing hemispheres. The UVVS will make profiles ofatmospheric species on the dayside and nightside as well as observations of the exospheric tail on departure. The VIRS will observe the planet near closest approach to sense cloud chemical proper-ties and near-infrared returns from the surface.>>

VEx can perhaps image the same areas at or (with not total loss of purpose -- the cloud formations don't utterly remake themselves in hours) a day or so before or after the Messenger observations.

Messenger's VIRS covers from 300nm to 1.45 microns (through the entire visible range) and will have resolution as good as 100 m at Mercury. I think along with the other instruments on VEx, the loss of science regarding atmospheric composition will be seriously blunted.

What's really lost with PFS is an ongoing record of temperature scans to correlate with vis/UV images of the clouds. Adding such an instrument to a radar orbiter would not mean as much without having vis/UV imaging to go along with it, and adding two major instruments to a planned craft is a heck of a redesign.

Remember, Japan is still planning to launch a Venus orbiter that *would* have pretty much these capabilities and arrive in 2010. This could be a big moment for Japan if they can get the data on the circulation.

[Guest_BruceMoomaw_*]

Bruce, would the procurement rules for Discovery allow a PI to add capacity to a mission if it is selected as a candidate for further study?

I don't think so; that falls into the "bait and switch" category.