Printable Version of Topic
Click here to view this topic in its original format
Unmanned Spaceflight.com _ Venus _ Bright spot on Venus
Posted by: Juramike Jul 30 2009, 09:33 PM
space.com story on mysterious cloud brightening on Venus:
http://www.space.com/scienceastronomy/090730-venus-bright-spot.html
...also spotted by an amateur astronomer.
Posted by: marsbug Aug 3 2009, 01:37 PM
Volcanoes at last? Or some strange artifact of venus alien atmosphere?
Posted by: Stu Aug 3 2009, 02:16 PM
Yaaay for the amateurs! But what a shame we don't have a spaceprobe orbiting Venus right now, ideally a European one, with a full suite of scientific instruments, that could spot something like this before observers here on Earth -
Hang on..? 
Posted by: remcook Aug 3 2009, 02:28 PM
It's bright in UV, which means there's probably some clearing of whatever it is that's absorbing UV on Venus (still unknown, but maybe something like FeCl3). I doubt it's volcanic, maybe a dynamical cause (plus some chemistry), but interesting nevertheless.
Posted by: MarsIsImportant Aug 4 2009, 01:19 PM
I wouldn't rule out volcanic just yet. We've never seen any volcanic interaction with the incredibly thick Venus atmosphere. So we cannot be sure how that would transpire. There could be some totally unexpected consequences for such an event. And if this is purely atmospheric in nature, then why haven't we seen something of this magnitude before?
I'm not ruling out anything at this point, including comet or large asteroid hit. But a comet hit is unlikely because we should have seen it long before it struck. If it blindsided the planet, then that would be equally unusual and unlikely.
In some respects this event might be more interesting if it is purely atmospheric in nature. We need more data. Does anybody have an idea where that might come from at this point?
Posted by: remcook Aug 4 2009, 01:48 PM
I think the space.com article said "We have seen such events before". The article also has Venus express images of the bright spot (and e.g. http://news.bbc.co.uk/2/hi/science/nature/8179067.stm ). It takes some time before spacecraft data is sent to Earth and processed and I don't think there's money for someone to look at all the hundreds of images coming in in real-time. And even if they saw it earlier, I doubt they would have put it on the internet straight away without making a press release or finding out what causes it.
But ideally, they should put all images on internet straight away of course 
Even then, these things are probably quickest spotted by amateurs like everyone here.
Posted by: cndwrld Aug 4 2009, 02:25 PM
To give people some idea of what to expect, a few thoughts on the process on Venus Express. The raw data comes down within about 18 hours of taking it. But sometimes bits and pieces will come down later; whether some data for an orbit comes down immediately, or parts of it come down a little later, depends on the circumstances (how much was taken, what our data rate is at the time, how much ground system time we have for the dump, etc). But I think all the bright spot data is down now. Then the images need to be calibrated. And then it takes time for people to figure out what is going on. The VMC (Venus Monitoring Camera) team consists of three people, so we're not talking about mobilizing big teams of people. They've begun talking to the Virtis team about cross-referencing their data sets, as the Virtis spectrometer probably covered it, too, at least partially. Since the pointing and commanding files are made four months in advance, we can't just drop what is planned and swing around and start taking new observations that aren't previously planned. So we'll have to see what we got. Then the teams are going to try to coordinate and see what they have jointly. And since they didn't plan on this spot being there, they'll have to determine what they can figure out from the originally planned observations.
In our planning, we plan one month for one month of observations, four months in advance. Two times per year, we 'double plan' two one-month periods at the same time, so that we have two periods of four weeks when there is no planning work done: around Christmas, and in late July/early August, to allow for extended holiday periods. Right now, a lot of the instrument teams are on summer holiday, so less will be getting done now until everyone ramps back up at the end of August.
So everyone on VEX is pretty excited to see what is going on. But nothing is going to be happening immediately.
Posted by: Stu Aug 4 2009, 02:47 PM
Good to hear the Venus Express team is excited by this and "on it". Appreciate you explaining the ins and outs of the observing process, too. Have to be honest tho, seems a bit of a faff about when the Hubble guys can just swing that great star cannon around towards Jupiter, take pics of the wound left by an impacting asteroid and comet and have them out on the web and being drooled over and Twittered around the globe within hours. But fair enough, I think we all realise now that things move rather differently within ESA, and I accept totally that retargetting a probe orbiting a planet is a very different task to retargetting a telescope.
But seriously, if anyone from ESA with influence over these things is reading this, it's really very, very simple: if you'd just find a way to put raws online there's an army of people out here ready, willing and able to work with you on making the most of them. We don't want paid, we don't even want feeding, we'd do it for free, just as we do with MER and CASSINI images. We do it for the challenge, the love of science and the personal satisfaction.
Posted by: Greg Hullender Aug 4 2009, 04:56 PM
Venus is usually too close to the Sun for Hubble to take pictures of it, but right at the moment it's about as far from the Sun (from our perspective) as it gets, so perhaps we can expect something from the Hubble guys too.
An asteroid seems like a good guess since it's very, very difficult for us to find asteroids with aphelia inside Earth's orbit. Another argument in favor of putting an asteroid-seeking telescope in a Venus-like orbit.
--Greg
Posted by: dvandorn Aug 4 2009, 07:37 PM
Ummm... let me get this straight. VEX ops are pre-planned four months in advance and nothing can be changed in those pre-planned ops plans? So that any follow-up on transient phenomena literally cannot take place for at least four months?
If that's the case, then we truly don't have a resource at Venus that can do anything at any given time except its pre-planned program, which will always be a good four months out of date. I guess we can take "respond to transient phenomena or rapid changes in environment" off the list of VEX's abilities. (I know, it's never been a claim of the project.... but, as Doug says, the whole thing gives me rage.)
But, to be fair... with what do I compare this? Can Cassini's op executions be changed after they are loaded into the spacecraft? If so, how quickly? How fast can Cassini respond to some changing circumstance? How about Hubble? We know Hubble had been packed solid with use requests and that it was still capable of being re-tasked to get Jupiter images within a week of the first detection of the impact on old Jove.
Maybe we're all just too used to ops plans like those for the MERs, where what we do tomorrow is highly impacted by what happened today. Obviously, many NASA probes (especially those in the outer system) don't have that kind of operational flexibility, either. So... how does VEX compare to other planetary probes in terms of being re-tasked?
-the other Doug
Posted by: imipak Aug 4 2009, 08:34 PM
In defence of ESA: the Saturn system, and Mars, are very different targets from Venus. The former change their appearance on very short time scales, and fairly frequently. Venus, as far as I know, does not. Unless I'm mistaken*, events like this are rare, which is why this event is news. Why would you design your spacecraft, and it's ops processes, around a rare event that might never happen during it's operational lifetime?
I second Stu's thanks to cndwrld for giving an inside perspective. We all understand money's as tight at ESA as everywhere else.
I think the contact point between the two perspectives surfaces here:
Why is it necessary for images to be calibrated and "figured out" before they are released?
(* include std.disclaimer. Cluestick welcome here .)
Posted by: remcook Aug 5 2009, 07:24 AM
"We know Hubble had been packed solid with use requests and that it was still capable of being re-tasked to get Jupiter images within a week of the first detection of the impact on old Jove."
I suspect it might have been more hard to do if the instrument was already in proper science phase. But perhaps someone would have been willing to give up time...
For Cassini I remember there was a re-design after discovery of Enceladus' plumes by the magnetometer. There were 4 months in between the flybys and I think this was an 'all hands on deck' kind of moment. Maybe John Spencer can tell more about this? The manpower for VEX is a lot smaller, but I suspect if there was really something big going on it would in principle be possible to change the design within a month or so if people put in all efforts (cndwrld?). I'm not sure it makes sense changing the designs in this case since VMC has a whole globe view at least every orbit. I wouldn't be surprised if they saw the entire atmosphere every orbit. What would you change in the observations and is it worth the extra manpower?
Posted by: ollopa Aug 5 2009, 01:17 PM
There are now some earth-based pictures on the VEX EPO site: http://venus.wisc.edu/multimedia_amateur.html
Posted by: MahFL Aug 5 2009, 01:27 PM
We are talking Europeans who go on vacation for a whole month.....can't interupt that....... 
Posted by: ugordan Aug 5 2009, 03:11 PM
You have a problem with that?
Posted by: stevesliva Aug 5 2009, 04:27 PM
From reading the Cassini status reports, the biggest rip-up is changing the trajectory, the second biggest is changing the pointing, and the third biggest is changing the timing. For timing updates, they have whitespace in their plans, for pointing updates they obviously have to throw out the old and begin anew, but they can do this with reasonable speed given proper motivation. A few weeks, I think?? But that is a special request.
Posted by: ugordan Aug 5 2009, 04:36 PM
I think it would take several weeks at least. New sequences are uploaded onto the s/c weeks ahead of execution and they would need to be worked out and tested and validated on the ground before that.
Posted by: john_s Aug 5 2009, 05:11 PM
The July 2005 Cassini Enceladus flyby was definitely a special case. The decision to change the trajectory to reduce the close approach distance was made in mid-April 2005, just 3 months before the encounter. There was already a fully-developed observation plan, but we only had to tweak the period around close approach (maybe +/- 30 minutes or something like that). It was a scramble, but of course it paid off big time. I don't think we've made a tweak of that magnitude at such short notice since then- usually even the detailed observation sequence is pretty much frozen 4 or 5 months out. I suspect that if there was a big impact on Saturn, say, something could be done to observe it with a lead time of a couple of weeks, but it would be a major effort that would take away from other high-priority planning work- not a decision to be made lightly.
You can be a lot more flexible in planning observations for a spacecraft that can happily sit tight while you figure out your next move, than for a spacecraft that's careening through the solar system at many kilometers per second!
John
Posted by: stevesliva Aug 5 2009, 05:12 PM
Yeah. And they need to hold the meetings where they tell the instrument teams on the wrong side of the spacecraft that their science is getting removed.
Posted by: cndwrld Aug 6 2009, 07:51 AM
If that's the case, then we truly don't have a resource at Venus that can do anything at any given time except its pre-planned program, which will always be a good four months out of date. I guess we can take "respond to transient phenomena or rapid changes in environment" off the list of VEX's abilities. (I know, it's never been a claim of the project.... but, as Doug says, the whole thing gives me rage.)
But, to be fair... with what do I compare this? Can Cassini's op executions be changed after they are loaded into the spacecraft? If so, how quickly? How fast can Cassini respond to some changing circumstance? How about Hubble? We know Hubble had been packed solid with use requests and that it was still capable of being re-tasked to get Jupiter images within a week of the first detection of the impact on old Jove.
Maybe we're all just too used to ops plans like those for the MERs, where what we do tomorrow is highly impacted by what happened today. Obviously, many NASA probes (especially those in the outer system) don't have that kind of operational flexibility, either. So... how does VEX compare to other planetary probes in terms of being re-tasked?
-the other Doug
Any other questions?
Posted by: tedstryk Aug 6 2009, 08:46 PM
With the slow Venusian rotation, if the white spot is caused by something ongoing on the surface and is superrotating with the atmosphere, wouldn't it become a white band?
Posted by: Phil Stooke Aug 6 2009, 09:40 PM
Good point. It would have to be one gigantic belch (if I can use that vulgar expression here) that rose into the upper atmosphere and rotated with it.
In the interests of science, I am now going to practice my belching. Results will not be posted.
Phil
Posted by: tedstryk Aug 7 2009, 11:41 PM
We need to check the satellite maps. If a big, white cloud has formed over southern Ontario, then maybe the events are similar.
Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)