Oh yes, after reading your reply I had a look at the transit map. And indeed, it will not be seen at all in Spain.
I am located far enough north in Europe that I expect to see most of the transit, but yes, it will start just after midnight.

A little more information about what Venus Express will be up to around the time of, and during, the Venus Transit on 05/06 June.

Venus Express will be making a sequence of observations around the time of the transit:


- The VMC camera will obtain sequences of images of Venus in UV, visible and IR during the time of the transit, from South to North latitudes.

- The VIRTIS imaging spectrometer (an imaging spectrometer that observes in the near-ultraviolet, visible, and infrared) team will obtain data in the visible channel from the South pole and southern latitudes.

- A full Sun disk Scan will be performed by the Spicav spectrometer (an imaging spectrometer that used for analyzing radiation in the infrared and ultraviolet wavelengths), just before the transit starts.

- there will be a solar occultation observation during the time of the transit, measured by the SOIR (Solar Occultation at Infrared) instrument team that will be used to observe the Sun through Venus's atmosphere in the infrared. This measurement is described here and more generally here. The SOIR team has a lot of information online and has a useful twitter feed at @BIRA_IASB . There will be 4-5 people from the SOIR team in Svalbard, observing the transit from one place in Europe (above the Arctic Circle) where it will be fully visible.

The Venus transit will be a special moment for the SOIR team and their colleagues in the scientific community. The SOIR commands that will be sent to the instrument will enable recording the spectra of CO2 on the whole Venus altitude range available to the SOIR instrument. These measurements will give us indirect information about the temperature. Absorption due to aerosols will also be investigated.

Thanks to collaborations with ground-based observers, simultaneous measurements have been planned, namely with Pr. T. Widemann (Observatoire de Paris, France) and Dr. B. Sandor (Space Science Institute, Boulder, Colorado, USA). Dr. B. Sandor will, for instance, observe the Venus transit from Mauna Kea, Hawaï, using the James Clerk Maxwell (JCMT) telescope.

The data obtained with SOIR and the telescopes will be compared. This will enable scientists studying the atmospheres of exoplanets outside our solar system to test their instruments against a known, real-world example.

Note that all data from VEX observations will not be downloaded to Earth until at least 48 hours after the transit, because there is no communication with the spacecraft when it is directly in front of the Sun.

There was too long a gap in the Venus Express status reports. We got pretty busy for a while. But the most recent one just went up on the VEX SciTech web page. Click on the Latest Status Report on this page. The next one should go up in a few days.

The VEX Status Report 246 is now on-line.

No. 246 - End of quadrature and eclipse seasons, continuation of the mission's longest Earth occultation season and start of the eighth Atmospheric Drag Experiment campaign
Report for the period 1 April to 28 April 2012

Click here and then click on the most recent date under "Latest Status Report".

Curious cold layer in the atmosphere of Venus even possible CO2 ice. Who could imagine on such a hot planet closer to the Sun.


More on this ESA page

full paper available here http://venus.aeronomie.be/multimedia/pdf/M...CO2_jgr2012.pdf

The latest Venus Express operations report, #247, has been put on-line. It covers May of 2012, and discusses:

* two orbit correction manoeuvres,
* the end of the eighth Atmospheric Drag Experiment (ADE) campaign, and
* the continuation of the mission's longest Earth occultation season.

We've added a couple separate sections to discuss changes over time in the Local Time at Ascending Node (LTAN) and the pericenter altitude.

The link to the page is here.

Another Venus Express operations status report has just gone up.

We plan four months in advance, and we wait to write the status reports until all the data and operations status are known, which to be truly complete is a couple months after the operations. The current report is #248, which covers our Medium Term Plan 80, or our 80th month of operations. This MTP covered 27 May to 23 June 2012.

This reporting period covered the transit of Venus during inferior conjunction, the continuation of the mission's longest Earth occultation season, and the start of the twenty-first eclipse season.

The report can be found in the VEX status report archive.

The latest Venus Express on-line status report is now available. The most recent report covers our operations in June and July of this 2012.

All of these reports can be found on the Venus Express section of the ESA Science and Technology pages. The VEX page is located at:

http://sci.esa.int/venusexpress

On that page, there is a section labeled with a link called "Latest Status Reports."

We hope that people will find these of interest.

There's a new press release from Venus Express about volcanism on Venus.

A new episode of active volcanism on Venus?

02 Dec 2012
For decades, planetary scientists have debated whether Venus possesses active volcanoes. The latest twist to the tale is provided by data sent back from ESA's Venus Express orbiter, revealing unexplained major changes in the amount of sulphur dioxide gas above the planet's dense cloud layer.

You can read the article here.

Glad to see this last update made it to the news in one of the main newspapers in Spain.

This is quite the week for reporting the detection of a substance on one of the inner planets. That's three for three!

This one might be the most meaningful. Venusian volcanism is an interesting foil to terrestrial thermal evolution.

To explore this quantitatively, I get that the mass of SO2 detected above 70km corresponds to about 1/3 of the SO2 released by the Mt. Pinatubo explosion on Earth (overall, with no altitude qualification) in 1991. That leaves unanswered how much SO2 might have behaved below 70 km, or whether or not there's a compelling reason to compare the volume (or composition) of venusian vs. terrestrial outgassing events, but at least it's interesting to see such a close correspondence in volume.

ESA Web Page Redesign Launchec

The web pages for the general public of the European Space Agency have been redesigned. The new Venus Express page can be seen at the usual location here.

The Science and Technology pages haven't been updated yet. The SciTech pages here will be updated in the future. The SciTech page links to the VEX status reports remains unchanged for now.

We've added a couple more status reports for Venus Express, covering July through September 2012.

You can find them by clicking on the links in the Latest Status Report box at
http://sci.esa.int/venusexpress.

Operationally, it was a pretty complicated summer.

In some of the terminator orbits of Venus Express, sequences of images were taken. One of those, from some time ago, have been made into a 12 second movie, showing the view from the spacecraft as it does one orbit around Venus. You can see it at www.esa.int/science where it is featured for now, and directly at http://www.esa.int/Our_Activities/Space_Sc...f_Venus_Express.

Nice! Lot of potential in those frames.

The latest Venus Express status report is on-line, with the results for mid-September to mid-October 2012. This is report 252, for our 84th monthly planning cycle (MTP084).
The Science and Technology page for Venus Express is here, and then you click on the Latest Status Report link.

29 January 2013

ESA’s Venus Express has made unique observations of Venus during a period of reduced solar wind pressure, discovering that the planet’s ionosphere balloons out like a comet’s tail on its nightside. The results are discussed on the ESA web page here .

The latest Venus Express status report is on-line, with the results for mid-October to mid-November 2012. This is report 253, for our 85th monthly planning cycle (MTP085).
The Science and Technology page for Venus Express is here, and then you click on the Latest Status Report link and choose report 253.

Latest Venus Express status report on-line for January 2013, at http://sci.esa.int/science-e/www/object/in...fobjectid=51597. It is, of course, written in the required humorless way. But I try to explain things so that people new to this stuff can understand it. If you find mistakes or things that aren't clear, please let me know.

And for your information, the ESA Science & Technology web pages (including for Venus Express) have been upgraded to a new format. It looks a lot better. The link to the Venus Express SciTech page is http://sci.esa.int/venusexpress.

The Venus Express Mission Operations Report 257, for our 89th monthly planning cycle, is now on-line.

It includes an overview of our simultaneous seasons of solar eclipses and Earth occultations, targets for the surface mapping campaign, and an explanation of how we manage orbit correction maneuvers as fuel and oxidizer tanks approach low liquid levels in zero gravity.

VEX Mission Operations Report 257 (Planning Cycle 089))

The Venus Express mission operations summaries now go up to the end of April 2013. Reports 258 and 259 are available.

These two reports cover the entry into, and exit from, the superior conjunction shutdown, automation of spacecraft passes at the Mission Operations Centre and thermal fuel gauging tests.

The status report archive is here.

I understand that measuring remaining levels of fuel in a spacecraft is something of a black art. That said, do we have an idea approximately how much fuel remains, and how long it's likely to last?

By the way, these are great -- thank you for posting them, and please do continue.


Doug M.

We typically get zero feedback for the public outreach stuff, so thanks for the note.

The fuel/ox level measurement is quite the black art. What we have right now is the numbers from the archaic but still prevalent method on all spacecraft: bookkeeping. Those numbers tell us that we can make it to at least December 2014 and probably a bit later. But there's enormous uncertainty in those numbers after 7 years of daily burns. The numbers from the new method are still being evaluated. And there's only been one advanced test, so we'll have one data point from that. Maybe next year we'll get more tests, and numbers. For now, that's all we've got.

You're very welcome! Seriously, I check in every couple of months and skim a bunch of these. Read like that, they're really interesting. A bit dry, but that's to be expected. They give a good picture of what it's like to actually run a spacecraft over time.



I assume that fuel is the limiting factor? If you had enough fuel to go to, say, 2016, there'd be nothing else that would stop you from continuing the mission?

Also, according to the mission FAQ online the plan is to decommission VE with a terminal burn into the atmosphere. Is that still the plan -- and if so, wouldn't you want a reserve of fuel for that final burn?


Doug M.

Well, the orbit would decay sooner or later, given the sun's influence. It's only a matter of how soon it will happened.

Right, but IIUC once they run out of fuel, they won't be able to stabilize the orbiter, and they'll lose contact with Earth. Whereas, if they keep a bit of fuel, they can get some science from that terminal orbit -- observations at a much lower altitude than they would otherwise have dared. At least, that's the plan with Cassini and with MESSENGER. Don't know about Venus Express.


Doug M.

The VEX spacecraft is in great shape. I'm continuously surprised by how robust it has been. All the usual consumables (batteries, wheels, solar panels, star trackers) are in great shape. Kudos to Astrium. We're just running out of gas.

The plan for the final day is, as you say, a controlled burn into the atmosphere. At Venus, we all get a Viking funeral. And the 'control' part is the hard part. But once the fuel is gone, there's always something left. We say 'fuel' and sort of mean three things: fuel, oxidizer (in our case, a dual system) and pressurant. When the fuel or ox runs dry, there's still impulse to be gained just by pushing out the other fluid. And even when both the fuel and ox are gone, you can still blow the helium out. Neither of the latter two options give you much, but we won't need much. Our apocentre is very high; just blowing helium out for a while would probably be enough to tip our pericentre low enough so that in a few orbits we'd be toast.

I'm sorry the status reports are so dry. Sigh. There's nothing I can do. The alternative is to have nothing at all.

It's the same with Mars Odyssey, Cassini, and MESSENGER. It really is striking how many long-lived spacecraft we have out there now. Even putting aside the Voyagers, I know of well over a dozen space probes and comsats that are over 10 years old and still in good repair and active. (And I'm sure there are plenty more that I don't know of.) It's particularly impressive for a probe like VEX that is in a challenging thermal and radiation environment.




So, basically you could alter your orbit by mechanical rather than chemical means! Very cool.

cheers,


Doug M.

Gravity Probe B spent a lot of time blowing out helium...

Got another status report through the system. I hope another couple will get through and get posted soon. The archive is HERE.

No. 260 - Automation of spacecraft passes, thermal fuel gauging tests, start of the twenty-fourth solar eclipse season and the fifteenth Earth occultation season
Report for the period 28 April to 25 May 2013.

This reporting period covers four weeks of Venus Express operations. It includes the automation of spacecraft passes at the Mission Operations Centre, thermal fuel gauging tests, start of the twenty-fourth eclipse season and the fifteenth Earth occultation season.

Yay! We got another status report out. It is here in the VEX Status Report Archive, and covers 26 May to 22 June 2013.

It includes continuation of the twenty-fourth eclipse season and the fifteenth Earth occultation season, implementation of the automation of spacecraft passes at the Mission Operations Centre, thermal fuel gauging tests, and handling of a spacecraft event time anomaly.

The press release on the gravity waves on Venus was finally posted.

Yes, gravity waves exist on Venus. And no, these are not waves in gravity, but waves in clouds which happen to be called 'gravity waves' and which are common on Earth when calm stratified air passes over a high physical obstacle.

The information is on this ESA Venus Express page.

Really interesting stuff!

Two things caught my eye. One, Venus Express' elliptical orbit is placing tight constraints on observation -- they can only get good information periodically. As is often the case with Venus, we're left thinking "if we just had another mission..." No disrespect to Venus Express, which has been doing amazing work for seven years now! But, man, it would be nice to get a fresh set of eyes there, and a close-up look at that crazy atmosphere.

The other thing was "We don't yet fully understand how such topographic forcing can extend to high levels". The "ripples over a submerged boulder" analogy is useful, but we're talking about waves that are ~10x higher than the obstacle that's creating them, propagating up to a level where the atmosphere is a small fraction as dense. The physics of that have got to be interesting.


Doug M.

It's more or less what Akatsuki was supposed to do. observe Venus'atmosphere continuously for up to 20 hours at a time.

Venus Express was deep into planning joint observations with Akatsuki, so we were very sad when VOI didn't work. But there's a chance they can get into some kind of orbit in 2015, so we live in hope. VEX won't live to see it, but we all hope it works for them.

Hopefully, I'll be alive when the next Venus mission arrives. Just so I can bore people with stories about how much harder it was in my day with Venus Express and Magellan. Did you know that for Magellan, there were no rockets? We had to get a big group of people together and throw the probe upwards.

Well, if the spring action in the shuttle bay hadn't worked, that might've been the backup plan.

Yeah, I hear you. When I was a boy, we had to walk to the Moon. Uphill. Both ways.



-the other Doug

After a four month delay, the Venus Express status reports are again being published. They're a bit behind; this one covers July and August of 2013. The report can be found here.

Venusian 'glory' hints that cloud chemistry is still not understood. Here's the (pay per view) paper.

The ESA page on the Venus glory paper is here.

In what context is "glory" canonical for this sort of thing? The term I first heard years ago referenced Ulloa, which seems to be "Ulloa's Halo," but I have to say that in recent googling "fogbow" is a good term.

The geometry also seems the same as Opposition Surge.

http://en.wikipedia.org/wiki/Glory_%28optical_phenomenon%29

There needs be some more linking between wikipedia articles. Because Ulloa, Boguer, and Fog Bow all duplicate some of that discussion.

Is "glory" canonical among pilots, then? Meteorologists?

[edit] Fog bow at least declares it's something different. Perhaps Antisolar point would be a good place to link to all the individual phenomena.

I'm not an etymologist but "glory" is a well-accepted term that appears in popular scientific literature all the time (see, e.g., the references at the bottom of the wikipedia article), at least in the United States.

Perhaps there is some technical distinction between different effects, or perhaps it's called something different in other countries.

Another VEX status report managed to get on-line, for August of last year. A couple more are queued up.

The report archive is here.

Graphs!

A guest post on the Planetary Society blog with a nice overview of recent findings related to possible evidence of volcanism on Venus, using Venus Express data.

Link here.

Another monthly report is on-line. This on covers 13 October to 9 November 2013, which included the continuation of quadrature operations, temporary star tracker outage, start of the sixteenth occultation season, and entire thirteenth Atmospheric Drag Experiment Campaign

It would be great if these on-line status reports were more up to date. But the teams are now preparing for a two-month aerobraking campaign, and at some random point the end of the spacecraft's fuel and therefore the end of mission. So these status reports are unlikely to get published at a faster rate until June or so.

On 11 April 2006, the Venus Express team held their collective breath and waited to see if the main engine would fire and put us into Venus orbit. Thanks to Astrium, the manufacturer, it went perfectly. And VEX has been in orbit now for 8 years.

Since no other missions to Venus are being planned by any agency, and the chances of Akatsuki getting into orbit next year are uncertain, the VEX database will likely be the baseline for future research for a long time. And as recent announcements about volcanic activity has shown, there's a lot of science yet to be pulled out of the data.

Nicely done, VEX. Nicely done.

Your updates on VEX have been invaluable, cndwrld. Thanks for keeping us informed!!!