VMC grows up

The news is out: our little VMC webcam on board Mars Express has achieved adulthood, of sorts! In a web article on 25 May, we announced that the VMC camera is being adopted as a professional science instrument.

Mars seen in May 2016 in three different views. Full details via http://www.esa.int/marstriptych2016 Credit: D. O'Donnell - ESA/Mars Express/VMC CC BY-SA 3.0 IGO - ESA/NASA/Hubble

Mars seen in May 2016 in three different views. Full details via http://www.esa.int/marstriptych2016 Credit: D. O'Donnell - ESA/Mars Express/VMC CC BY-SA 3.0 IGO - ESA/NASA/Hubble

The article reads, in part:

This spring, ESA began working with the Planetary Sciences Group of the University of the Basque Country, Spain, for an initial two years to develop software and conduct studies of images, effectively promoting the humble camera to the level of professional science instrument.

“The analysis will help us understand the global martian context of data acquired from other instruments, provide data on clouds, dust and atmospheric structures and enable surface features to be accurately characterised, for example, by tracking variations in the Mars polar ice cap,” says Agustín Sánchez-Lavega, heading the group.

ESA's Mars Express Project Scientist Dmitri Titov is delighted that the camera is opening up a new range of investigations at Mars: “Cloud tracking and dust storm monitoring, for example, are significant topics in the planetary community, and it will allow us to extend Mars Express science ‘into the atmosphere’, filling a gap in the spacecraft’s science portfolio.

The good news is that the transition to a science instrument won't interfere with the ongoing delivery of VMC images for immediate public viewing and for continued use in outreach, education and citizen science. You remain more than welcome (highly encouraged, in fact!) to access the image sets and use them for your own analysis, processing and sharing (details on CC licensing here).

Working on VMC outreach, education and PR has been one of the most interesting and satisfying projects I've been involved with here at ESOC in recent years. I have thoroughly enjoyed being in touch with, and working with, a lot of enthusiastic folks – some within ESA, many external – all of whom have been motivated by the love of science, interest in Mars, support for education and working with an active community.

While I thoroughly enjoyed seeing (and sharing) the many VMC submissions that people on several continents sent it over the years, the most enjoyable activity for me was definitely the 2015 VMC Imaging Campaign aimed at schools, astronomy clubs, science centres and other youth groups.

The level of participation was fabulous (25 groups from the US and Europe) and the resulting work was really well done. It was a genuine pleasure to work with the MEX flight control team here to host a series of Google Hangouts, issue the challenge, receive the imaging requests and then actually conduct the dedicated observations. This might have been the first-ever allocation of multiple orbits of an interplanetary craft to schools and young folks! And it was also a pleasure to see that some groups chose to submit artistic work based on the resulting images, in addition to those who sent in more traditional science projects.

It was also a pleasure working with pro-, semi-pro- and amateur (but v. enthusiastic) planetary science nuts located all over the place!

One of the most active supporters of VMC since the beginning has been Emily Lakdawalla – herself a planetary scientist – who blogs over at the Planetary Society. Emily has done an excellent job over many years highlighting numerous ESA missions, and she was a keen 'early adopter' when the VMC images first became available in 2007/08. She promoted and shared VMC images, and designed and hosted online tutorials to help those interested in working with the images learn some of the techniques, and she inspired many others to get involved.

I asked Emily for a few comments, and she sent in this:

The VMC demonstrates the power of a simple camera for exciting the public about the adventure of space exploration. Its images are not large but they are the only ones arriving from any Mars spacecraft that show us Mars as a round planet in all its changing phases and seasons – a view out the porthole of an interplanetary ship. I'd like to see simple, small, wide-angle cameras on all spacecraft to provide context to tell the story of robotic space exploration.

It's appropriate, however, to take this opportunity to thank everyone who has contributed to VMC since its recommissioning in 2007. People have contributed time, software, knowledge, support to outreach activities, organisational efforts and enthusiasm – and so much more – helping make the VMC outreach effort a real success!

To everyone here, in alphabetical order, a huge thanks!

  • Stuart Atkinson
  • Johannes Bauer
  • Maria Bennett
  • Jean-Pierre Bibring
  • Michel Breitfellner
  • Marcello Cappelletti
  • Alejandro Cardesin
  • Michel Denis
  • Bill Dunford
  • Doug Ellison
  • Paolo Ferri
  • James Godfrey
  • Brigitte Gondet
  • Hannes Griebel
  • Andy Johnstone
  • Michael Khan
  • Rene Kloos
  • Emily Lakdawalla
  • Daniel Lakey
  • Jocelyne Landeau-Constantin
  • Luke Lucas
  • Stefan Luders
  • Mike Malaska
  • Thomas Ormston
  • Gordan Ugarkovic
  • Manfred Warhaut
  • Simon Wood

If I inadvertently left someone's name off the thanks list, DO let me know!!!!

Last but by no means least, I'd like to thank everyone who has ever downloaded, tinkered with, mashed up, colour-processed, artistically rendered, analysed, processed, shared or in any other way had total fun messing with VMC images. You guys are an inspiring community and it has been your enthusiasm that has made the VMC project a success.

If you're looking for a nice, historical overview of VMC activities with many updates from the folks who did a lot of the work, there's no better place than the VMC thread over at UnmannedSpaceFlight.

PS: As Emily pointed out in a separate email, a couple of our VMC community members have since gone on to great things: Both Mike Malaska and Bill Dunford have been absorbed by NASA/JPL!

VMC switched on: We’re back!

Today's post sent in by Mars Express Spacecraft Operations Engineer Simon Wood, at ESOC. The news? Ten observations slots in the next four weeks, starting today!

You may have noticed that VMC has been very quiet over the last few months.

Mars Express left Earth for Mars on a six-month journey in June 2003, when the positions of the two planets made for the shortest possible route, a condition that occurs once every twenty-six months.

Mars Express left Earth for Mars on a six-month journey in June 2003, when the positions of the two planets made for the shortest possible route, a condition that occurs once every twenty-six months. Credit: ESA/Medialab

This was due to Mars Express experiencing one of its regular 'eclipse seasons'. As our orbit precesses around Mars, there are periods during the year during which, for part of the orbit, Mars is between the spacecraft and the Sun. These eclipses can last for up to 40 minutes per orbit with the result that, during this part of the orbit, no power is generated by the solar arrays. This means that your spacecraft is running on battery power only.

This most-recent eclipse season also coincided with aphelion, the point at which we are at our greatest distance from the Sun. This is more pronounced for spacecraft orbiting Mars than for those orbiting Earth, as Mars' orbit is more elliptical than Earth's.

Being further from the Sun also means the total solar energy reaching the spacecraft is lower -- meaning the total output power of the solar arrays is reduced. The energy from the Sun doesn't only generate electrical power; as it strikes the body of the spacecraft, it also heats it up.

We have strict temperature requirements for our internal systems and payloads to keep them operating normally; this thermal control is managed by a number of electrical heaters and radiators placed around the the spacecraft. As the overall heat being provided from the Sun is reduced in an eclipse, then the electrical heaters have to work harder and thus draw more power to maintain the required temperature.

The end result of all this is that we have a situation where we have long periods using only the batteries combined with higher power usage by the heaters but less overall power being generated by the solar arrays to recharge the system.

This poses some difficult planning challenges as we have to take steps to reduce overall power consumption and carefully manage the spacecraft subsystems to ensure that we can fully recharge the batteries by the end of each orbit.

In this last season, this has meant doing things like reducing the amount of time the transmitter is on (as this consumes a lot of power) and this has had a knock-on effect on science operations as it means that the overall data volume we can transmit back to Earth is reduced.

The other thing we do is try to lower the workload on the thermal control system and reduce the power needed by the heaters. This is done by a special spacecraft pointing we call 'Warm-up'. Here, whenever the spacecraft is not pointing the instruments at Mars or the antenna at Earth (these are fixed to different faces of your spacecraft – Ed.), we point the base of the spacecraft directly at the Sun – the idea being that this will ensure that all the solar heat will go into the key fuel lines and the avionics mounted there and so the heaters that support them will have to work less to maintain their temperature.

We estimate this saves us 15-20W of heater power per orbit.

So how does this affect VMC?

Whilst VMC itself consumes very little power, it is these 'Warm-up' pointings that prevent us from using the camera. The parts of the orbit in which we would normally conduct VMC observations are taken up with Warm-up instead.

The good news is that Mars Express is now coming to the end of the current season, the eclipses are down to just a few minutes and their length is dropping rapidly – meaning Warmups are no longer needed. This has enabled us to re-activate VMC.

The first observation takes place on 29 February and we have managed to plan a total of 10 observation slots over the next four weeks.

Whilst the camera as been off for while, there has been plenty of exciting work going on behind the scenes in the last few months and we hope to be able to bring you more details on this shortly.

– Simon

Auto-posting temporarily off

Looking for the latest info on the VMC Schools Campaign?
Follow the Mars Express blog.


UPDATE 31 August: Auto-posting is back on!

As part of the VMC Schools Campaign, Mars Express is now using VMC to acquire over 2000 images of the Red planet; the first imaging orbits were yesterday, and the final runs tonight through until Wednesday morning.

In order to give priority to the 25 schools, youth clubs and organisation taking part in the VMC Schools Campaign, we have temporarily turned the auto-posting function OFF. This means that the VMC images acquired yesterday, today and tomorrow morning will not appear here in the blog or in the Flickr channel at this time.

We will release these as usual in the future, once the participants have had an opportunity to start working with their images.

VMC Imaging Campaign

Welcome to the VMC Imaging Campaign!

Information for schools, astronomy clubs, science centres and any other eligible group wishing to take part. Official hashtag: #vmcschools

NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft successfully entered Mars’ orbit at 04:24 CEST on 22 September 2014. This image was acquired by the low-resolution VMC camera on board Mars Express at 14:50 CEST on 20 September, when MAVEN was an estimated 312,000 km from Mars. Credit: ESA/MEX/VMC

NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft successfully entered Mars’ orbit at 04:24 CEST on 22 September 2014. This image was acquired by the low-resolution VMC camera on board Mars Express at 14:50 CEST on 20 September, when MAVEN was an estimated 312,000 km from Mars. Credit: ESA/MEX/VMC/CC BY-SA 3.0 IGO

Mars is approaching solar conjunction where it will be on the opposite side of the Sun from Earth; this will affect communication with the spacecraft for a period of about five weeks and so science observations have to be stopped.

During this particular Solar conjunction, the Mars Express team will be stopping science four days earlier than usual for operational reasons. Part of this time is to be used to run tests on spacecraft subsystems, but we have an exciting plan with what to do with the remainder!


 How would you like to be a scientist on a Mars mission?


 Read full details in the Mars Express blog

CC licensing for all VMC images

Effective immediately, all VMC images - past, present and future - are released by ESA under a CC license.

CC BY-SA 3.0 IGO

CC BY-SA 3.0 IGO

This work is licenced under the Creative Commons Attribution-ShareAlike 3.0 IGO (CC BY-SA 3.0 IGO) licence. The user is allowed to reproduce, distribute, adapt, translate and publicly perform this publication, without explicit permission, provided that the content is accompanied by an acknowledgement that the source is credited as 'ESA - European Space Agency’, a direct link to the licence text is provided (see example below) and that it is clearly indicated if changes were made to the original content. Adaptation/translation/derivatives must be distributed under the same licence terms as this publication. To view a copy of this license, please visit creativecommons.org/licenses/by-sa/3.0/igo

Credit: ESA - European Space Agency, CC BY-SA 3.0 IGO

Access the full VMC image archive

It's been a busy week for Mars with the announcement that NASA's Curiosity rover has made the first definitive detection of Martian organic chemicals in material on the surface (see "NASA Rover Finds Active and Ancient Organic Chemistry on Mars"). We've known for some time that there's methane in the atmosphere (see "Mars Express confirms methane in the Martian atmosphere"), but this is the first confirmation of organic carbon in a rock on Mars.

Our own (much more modest!) contribution to Mars news this week comes right here at the VMC blog.  We are delighted to announce that, in addition to the full image sets in Flickr, the entire VMC RAW-format image archive is now available for download.

The archive contains the unprocessed versions of every image the VMC camera on Mars Express has ever taken since launch back in 2003. These include the 2003 Beagle separation images, the Earth observation from 2014 and the images used to create the 2012 full orbit videos!

The data are available in two ways:

  • There are zip files containing the full image set for each individual observation with the date and time of the observation in the zip file name; these are arranged in folders for each year/month with subfolders containing that month's observations.
  • We also have full yearly sets of observations for download to make it easier for those who want to get the entire dataset; note the gap between 2003-2007 is due to VMC not being used in this period.

These files are contain exactly what was/is sent back to Earth from Mars Express. The only processing performed by the mission team at ESOC is to extract the image data from the packets received from the spacecraft and assemble these into the individual raw-format image files (as each image is split across several packets). As a result, anyone who wants to have a go at processing these files is working with genuine raw spacecraft data.

Note that for Flickr, we currently run the downloaded images through a standard set of tools to adjust contrast sharpness and colour levels – exactly the same processing is done for every image VMC acquires. While this produces some good pictures, it is clear that tailoring processing to a specific image can bring out even more details and an even better end result.

We invite you to give it a try! Some of the best VMC images we have seen have been those processed by members of the public.

Further information about the image format and about VMC itself can be found in our FAQ page.

More cool news

The other big upgrade we can announce is that the extraction and upload of the files downloaded from Mars Express – both to the raw archive and Flickr – has now been automated such that the images will be available in both archives within hours of them arriving on Earth, day or night.

This automated process is also now connected to the @esamarswebcam Twitter account, so when new images are uploaded, anyone who follows this account will be notified straight away! So, really, following the @esamarswebcam Twitter account is the best way to be kept up to date with VMC images as they are delivered live from Mars!

– Simon Wood
MEX Spacecraft Operations Engineer

Welcome, Maven!

On behalf of ESA's entire Mars Express team, Welcome Maven! We thought you might enjoy a whole-disk image of your new planetary home.

NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft successfully entered Mars’ orbit at 04:24 CEST on 22 September 2014. This image was acquired by the low-resolution VMC camera on board Mars Express at 14:50 CEST on 20 September, when MAVEN was an estimated 312,000 km from Mars.

NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft successfully entered Mars’ orbit at 04:24 CEST on 22 September 2014. This image was acquired by the low-resolution VMC camera on board Mars Express at 14:50 CEST on 20 September, when MAVEN was an estimated 312,000 km from Mars. Credit: ESA/MEX/VMC

This image was acquired by the low-resolution VMC camera on board Mars Express at 14:50 CEST on 20 September, when MAVEN was an estimated 312,000 km from Mars. Credit: ESA/MEX/VMC

Earth seen from Mars: We are here

As you have seen from our recent blog posts and Flickr updates, VMC has been busy capturing some spectacular views of Mars.

However on 3 July, we once again turned away from Mars to look towards a more distant target.

Earth seen from Mars. Credit: ESA/Mars Express/VMC

Earth seen from Mars. Credit: ESA/Mars Express/VMC

Ever since our successful test of the VMC camera's long exposure mode (which brought us our first direct images of Phobos), there's one observation we've been keen to attempt:

An image of Earth!

Our chance observation of Jupiter in April served double duty as a dry run to evaluate if VMC stood a chance of detecting the famous pale blue dot.

With the success of the Jupiter pictures, we felt there was a good possibility that, whilst Earth would likely be faint, it would just be visible.

However, imaging Earth from a Mars-orbiting spacecraft using a camera with no specialised optics is not as simple as it sounds. So we thought we'd provide a brief overview of the kind of things that go into taking a picture like this.

One of the first issues we had deal with was determining the optimal time to take the photo.

Earth and Mars are both orbiting the Sun at different rates, so the angle between them regularly gets larger then smaller.

The larger the Mars-Sun-Earth angle, then – when viewed from Mars – the larger the percentage of Earth that is illuminated. So, you might conclude that we should take the image when this angle as big as possible.

However there are two problems with this:

  1. If this angle is very large, then Earth is much further away from Mars and thus will appear much smaller.
  2. The larger this angle gets, when we look towards Earth from Mars, the narrower the Mars/Sun angle gets. This means that the Sun will then be in the field of view of the camera.

This is not only prohibited in the interests the safety of our instruments but would also mean imaging something as faint as the Earth would be impossible as the light from the Sun would blind the camera.

The problem is illustrated below.

Mars-Sun-Earth angles. Credit: ESA

Mars-Sun-Earth angles. Credit: ESA

So what we needed was some middle ground, a period where the angle is large enough such that a sufficient amount of Earth is illuminated, but not so large that the Sun is too close to the camera's field of view.

With the help of JPL's HORIZONS solar system ephemerides computation service we were able to work out that the solid angle of the illuminated fraction of Earth was at its maximum on 21 June this year. We then tried to find an observation opportunity as close to this date as possible.

To keep the Sun as far from the camera's field of view as possible, it was decided we would not aim to have the Earth in the centre of the image, but instead offset it by 10 degrees.

The solid angle of the illuminated fraction of the Earth was at its maximum on 21 June this year. Date via JPL Horizons. Credit: ESA

The solid angle of the illuminated fraction of the Earth was at its maximum on 21 June this year. Date via JPL Horizons. Credit: ESA

The next issue we encountered was the need to tell the spacecraft to point VMC at Earth.

On Mars Express, our instrument platform is fixed to the spacecraft, so to point our instruments at a particular spot we have to turn and point the entire spacecraft.

To determine where we point the spacecraft, first the instrument teams have to tell our Science Planning team based at ESAC, in Spain, where they want their instruments to point and when. This is processed by the science planners and then sent here to ESOC to the Mars Express mission planning team.

Our mission planning system takes in all of the pointing requests that our science planners have sent, analyses them to check for critical factors like power consumption, illumination of the solar arrays and data generation as well as other constraints and requirements.

Screenshot: Mars Express mission planning system. Credit: ESA

Screen shot: Mars Express mission planning system. Credit: ESA

If all checks are OK, one of the outputs is a list containing an entire month's set of spacecraft pointings.

To fit in with this process, we generated a single new VMC 'Earth' pointing by using a software tool we developed ourselves. This new pointing was then added to the monthly list sent by the science planners and processed and checked by the mission planning system.

This set of spacecraft pointings is then sent off to the flight dynamics team here at ESOC. They are able to determine the spacecraft's exact position at any point in time.

Combining this information and knowledge of the spacecraft layout and the position of each instrument, they are able to calculate the orientation the spacecraft must have for it to point a specific instrument toward its desired target.

These calculations are performed for an entire month of observations, while checking that the pointings do not violate any safety constraints. Implementing, maintaining, enforcing and providing strict constraints protects delicate optics and sensors against the perils of excessive heating and over-illumination by the Sun.

As with all spacecraft pointings, our custom Earth pointing had to pass these strict tests for us to be permitted to attempt the observation.

After flight dynamics completed their analysis, the results were then returned back to mission planning, where they can be converted into sets of commands for the spacecraft's attitude and orbit control system.

Once these commands are generated they are checked by the mission planners and the flight control team before being uplinked to Mars Express (once per week).

At this point, the observation has been scheduled, the pointing commands have been generated and checked and up-linked to the spacecraft and the final stage was to then create the command sequence to operate the camera.

This involves telling it when to switch on, how many images to take, the exposure settings to use and when to switch off – and to tell the on-board computer to generate a report of the amount of data the observation produced to enable us to keep track of the volume of stored data on board the spacecraft.

As we expected Earth to be faint, and to maximise our chances of getting a decent image, we decided to use the same settings as our Jupiter pictures, as they contained a wide range exposures from 30 seconds down to 2 seconds.

VMC Earth observation commands in the Mars Express mission control system. Credit: ESA

VMC Earth observation commands in the Mars Express mission control system. Credit: ESA

Once this is all on board the spacecraft, we then have to wait until the images are taken and then down-linked, where we can then run them through our processing tools.

So after all that, here it is.. the Earth, at a distance of 150 031 705 km taken on 3 July 2014 at 15:52 CET from orbit around Mars.

Earth seen from Mars. Credit: ESA/Mars Express/VMC

Earth seen from Mars. Credit: ESA/Mars Express/VMC

The bright patches you can see are sunlight hitting the top of the recess VMC sits in and then being reflected off the camera lens.

However, on the 2-second exposure, this glare is reduced sufficiently to leave Earth clearly visible in the middle left of the image (Note: the colours here are the result of the processing tool we run the VMC images through).

At first glance it doesn't look like a particularly exciting photo. Some lens flare and a small faint dot are visible.

Earth seen from Mars. Credit: ESA/Mars Express/VMC

Earth seen from Mars. Credit: ESA/Mars Express/VMC

However, remember: there are 7 billion people living on that small faint dot!

This quote from Carl Sagan describing the famous Voyager 1 photo 'pale blue dot' sums it up rather nicely:

Consider again that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every 'superstar,' every 'supreme leader,' every saint and sinner in the history of our species lived there.

As usual, these images along with every other photo VMC has taken are available on our flickr channel.

Editor's note: Thanks to Simon Wood and the entire MEX team for these excellent images and report.

 

Mars seen today

Excellent views of Mars acquired by the VMC today at 07:00 CEST (05:00 UTC), and downloaded within hours, transmitted to ESOC in Darmstadt, processed by the Mars Express team and... here it is! Thanks to the MEX team and Simon Wood.

Mars at 08:00 CEST today, with the MER-B landing site annotated. Credit: ESA/Mars Express/VMC

Mars at 07:00 CEST today, with the MER-B landing site annotated. Credit: ESA/Mars Express/VMC

Hot on the heels of yesterday's images, here are today's set fresh off the spacecraft; again we see possible clouds/dust round the poles.

These images were taken at an altitude of 9900 km above the surface at 07:00 CEST (5:00 UTC) this morning and transmitted back to Earth at 13:15 CEST (11:15 UTC).

This rapid turn around is in part due to the current Earth - Mars distance being 'only' 123 336 112 km. At this distance it only takes 6 mins 51 seconds for signals travel from the spacecraft to Earth. (As we get further away this can increase to up to 25 minutes.)

One-way light timePropagation delay display on the Mars Express Mission Control System

This proximity gives us higher data transmission rates, which mean we can transmit more of the stored data from the science instruments – and thus occasionally leaves us with spare data downlink capacity in some of our ground station passes. This spare capacity enables us to schedule the VMC data dumps much closer to the VMC observations.

Continuing from yesterday's highlighting of the Phoenix lander, here we have marked the landing site of the NASA Mars Exploration Rover B - Opportunity.

Opportunity is a fellow seasoned Martian explorer; it was launched only 5 days after Mars Express on 7 June 2003, landing on 25 January 2004 – one month after we entered Martian orbit.

This false-colour image of the interior of 'Endurance Crater' on Mars was collected on 4 August 2004 by NASA's Mars Exploration Rover Opportunity. It was relayed to Earth via ESA's Mars Express. The image, taken with the Rover's panoramic camera, was relayed to Earth by ESA's Mars Express together with other scientific data. Three separate frames, taken through red, green and blue filters, were combined to produce this colour image. NASA/JPL/Cornell

This false-colour image of the interior of 'Endurance Crater' on Mars was collected on 4 August 2004 by NASA's Mars Exploration Rover Opportunity. It was relayed to Earth via ESA's Mars Express. The image, taken with the Rover's panoramic camera, was relayed to Earth by ESA's Mars Express together with other scientific data. Three separate frames, taken through red, green and blue filters, were combined to produce this colour image. NASA/JPL/Cornell

Its landing site is located in the Meridiani Planum, an area of interest due to concentrations of the mineral Hematite, which on Earth is often formed in the presence of water.

With the possibility of water-formed minerals located here, it is not surprising that this is an area also investigated by our mineralogical Spectrometer OMEGA and our high resolution camera HRSC.

As with Phoenix, its sister rover Spirit and, currently, Curiosity, Mars Express has performed communication activities with Opportunity over the years, including the relay of the image above from the surface back to Earth.

As usual, the full set of this morning's images is available in Flickr.