Tag Archives: DPAC

Asteroids at the “photo finish”

Today's Gaia blog post is contributed by Paolo Tanga, Associate Astronomer at the Observatoire de la Côte d’Azur, Nice (France). We tend to think that a still picture, shot with an ordinary camera, represents a subject at...

Enter GBOT

We should all know by now that Gaia is destined to study the motions and locations of 1 billion stars, but did you know that in order to achieve this goal, the precise location of the spacecraft itself is needed to an extremely high precision? In addition to the expert tracking methods utilised by ESA's mission operations team at ESOC, ground- based observatories also provide important data. Enter GBOT, the Ground Based Orbit Tracking campaign that utilises a network of small-to-medium telescopes aiming at doing just that. In fact, GBOT is committed to deliver one set of data per day, which allows the determination of Gaia’s position good to 20 milli arcseconds. GBOT's...

On the edge of the possible

It is probably hard to overestimate the effort required to coordinate the Gaia hardware and software development. While the industrial consortium EADS-Astrium developed the actual satellite and onboard software, the Data Processing and Analysis Consortium (DPAC) is responsible for the scientific data processing. As explained in an earlier blog entry, DPAC consists of several hundred people in dozens of scientific institutes spread all over Europe. Because the scientific requirements of the Gaia measurements are on the edge of what seems physically possible, every aspect of the hardware must be understood and calibrated to an unprecedented level – I will give an example below. This has led to a constant exchange between scientists...

Some Gaia numbers

We have heard and read many numbers about Gaia: the number of stars and other objects that it will observe, the maximum observable magnitude, the microarcsecond of accuracy and the remarkable focal length of 35 m. We have also read that such a powerful telescope on Earth would be able to detect a button on the spacesuit of an astronaut on the Moon. But let’s look at more hidden numbers. It took over 3.5 million hours to study, design, build and test Gaia. That’s about 300 people working full time for 7 years, spread over 74 different companies and 16 countries. Meanwhile the design and implementation of the science and the operations...

Opening (activating) the gates of Gaia

As you may know already from previous blog entries Gaia will fly the biggest camera ever into space. The image created by the two telescopes will be huge: about 1 m wide and 0.5 m high. To cover this entire area you need 106 different CCDs (detectors). Most of them are white light CCDs. Additionally there are blue sensitive (BP) and red sensitive (RP) CCDs. About one billion pixels (picture elements) are distributed over the focal plane as each CCD consists of about 9 million pixels. CCD images can have saturated pixels as you may have experienced with your digital camera when taking photos or videos and a bright light source is...

Gaia data processing

In a previous blog entry you have learned about the rehearsals taking place in preparation for the Gaia data processing. Unlike a mission such as the Hubble Space Telescope, Gaia does not produce data that is immediately scientifically useful. The raw telemetry must first be processed before we can obtain the sought after distances, motions, and properties of the stars observed by Gaia. This immense task will be undertaken by a pan-European collaboration, the Gaia Data Processing and Analysis Consortium (DPAC). The DPAC consists of about 450 persons, spread over academic institutes and space agencies throughout Europe and beyond, who are actively contributing to writing the millions of lines of code needed...

Operations rehearsal 4

Once Gaia is flying it will send a daily stream of scientific data to Earth. The Missions Operations Centre receive this and transfer it to the Science Operations Centre in the European Space Astronomy Centre (ESAC), the ESA establishment near Madrid in Spain.  At ESAC, “Initial Data Treatment” is carried out as well as running the First Look software to assess the instrument health. The processed data is then sent to the other data processing centres around Europe (Barcelona, Cambridge, Geneva, Turin and Toulouse).  A group of payload experts also look at this data to confirm the performance of the instrument. Depending on what the payload experts find, small changes or calibration...

Gaia – Surveying a billion stars

Welcome to ESA's Gaia blog! Gaia is a global space astrometry mission. It will make the largest, most precise three-dimensional map of our Galaxy by surveying more than a thousand million stars. In this blog we'll cover the activities from Kourou from once the spacecraft has left the clean room in Toulouse until launch. And we'll include guest blogs from outside of Kourou - to give you an idea of the other things that are happening in the wider Gaia community. Details shortly...Watch this space!