Tag Archives: testing

Commissioning update

The Gaia project team provides an update on the ongoing commissioning activities of ESA’s billion star surveyor… The work done to bring online all components of the Gaia service module, which houses equipment needed for the basic...

Installation on the launch adapter

Following the filling of the tanks, the Gaia satellite enters the Combined Operations Phase: the “COP”. This involves all the different stages by which the satellite is put on to the launcher, the launcher is put on the launch pad, and the launch itself. All of the activities on the satellite are carried out at this time according to a schedule established by Arianespace, who also manage all of the active participants of this combined phase: Astrium as the prime contractors of the satellite, Roscosmos for the Russian launcher, RUAG for the payload adapter and the clamp band, Arianespace or its subcontractors for the electrical testing of the launcher, and CNES for...

Gaia ready for fuelling

Towards the end of November, the first part of the Gaia launch preparation was complete: the satellite was 90% ready, with its tanks pressurised. The second part begins with filling the tanks with the appropriate propellants. This phase is particularly dangerous because the propellants are toxic, and there is also a risk of explosion, so it is carried out in a dedicated building. That’s why Gaia had to move from building S1B in the payload preparation complex (EPCU), where it has been since the start of the campaign, to the S5 building to be fuelled. How do you move Gaia from one building to another? Gaia, complete with its sunshield, could not...

Gaia is whole again

After a month full of uncertainties, Gaia transponders are back and in good health. Following their business class return flight to Kourou, both Gaia transponders have been re-integrated in the spacecraft, re-connected, and functionally verified. At the completion of five days of intensive testing, all results were positive, allowing the re-installation of the solar array panels and of the multilayer insulation (MLI) blankets, which had to be removed for operator access (see picture). This progress allows the team to reaffirm the recently agreed launch date of 19 December. As of Monday 25 November, we will be able to resume the spacecraft preparation, beginning with pressurisation of the gas tanks. This is a...

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...

The pieces of the puzzle are coming together

The activities on the spacecraft are almost finished. The great achievement of last week was the smooth deployment of the sunshield. The Astrium and Sener teams are now giving the final touch to configure the satellite for flight. This week we will check for the last time the leak tightness of the propellant tanks and then Gaia will be ready to move to another building (called S5A) where it will be fuelled. With Gaia almost ready it was time to have a look to other pieces of the puzzle. We therefore paid a visit to the MIK building (MIK is the Russian acronym for the huge hall where the three stages of...

video

Gaia sunshield deployment time lapse sequence

Here are some nice time-lapse sequences from the deployment test of the Gaia Deployable Sunshield Assembly (DSA) on 10 October 2013, in the cleanroom at Europe’s spaceport in Kourou.     Since the DSA will operate in microgravity, it is not designed to support its own weight in the one-g environment at Earth’s surface. Therefore, during deployment testing on the ground, the DSA panels are attached to a system of support cables and counterweights that bears their weight, preventing damage and providing a realistic test environment. Once in space, the sunshield has two purposes: to shade Gaia’s sensitive telescopes and cameras, and to provide power to operate the spacecraft. Gaia will always...

Pyrotechnic and 24 bangs: The sunshield deployment

Several cameras have been strategically positioned around the spacecraft and programmed to take a picture every 3 seconds. Inside the cleanroom, utter silence pervades, which is interrupted only by the regular clicking of the cameras. Three windows provide a view of the cleanroom from the rooms outside. Behind those windows, the rooms teem with people. All eyes are glued to the spacecraft. The anticipation in the air is sliced by the sudden ringing of a red telephone on the wall. We’ve been expecting the call: the software team is ready to command the deployment sequence. There is only time for one last quick check: are we good to go? The team leader...

Installing the Gaia Sunshield

Six in the morning in Kourou: outside it is still dark, but the thermometers are already reading 24 degrees Celsius, and the relative humidity has remained 92% through the night. After sunrise at 06:18 today, the temperature will climb to reach a maximum of 34 degrees in the afternoon. The Gaia spacecraft, however, is inside the cleanroom, where the temperature is maintained at a constant 23 degrees. Air is circulated through filters to preserve a clean environment, and the humidity in the cleanroom will be kept at about 50%. In the airlock leading to the cleanroom, the Astrium Assembly, Integration and Testing (AIT) team and the SENER Sunshield team are getting ready...

Another day in the life of a Gaia test engineer

In the middle of last night, we received in Kourou a disturbing call from the Gaia control centre, located in Darmstadt, Germany. Although for us it was middle of the night, it was already morning in the control centre. So what happened? Although often announced in the media as having the biggest camera on board that has ever flown in space, Gaia does not actually take pictures in the sense as you and me taking pictures on a holiday trip. Instead, it rather tracks the stars across its sensors as the telescopes rotates and the field of view moves across the star filled sky. In order to do so, a constant readout...

Inspecting the Soyuz facilities

The previous blog entries have given an overview of the activities of the last few weeks: from the arrival of the spacecraft in Kourou to the successful test of the Launch and Acquisition Mode (LAM) – the initial operational mode of the spacecraft during and after launch up to the contact with the ground stations. Another recent activity was the inspection of the Soyuz facilities and especially the VS06 rocket (Soyuz Flight number 6), which will now launch Gaia, after the switch with the O3B project. The first thing that catches your eye is a depot with 40 massive containers that are shipped from St. Petersburg by boat. The Soyuz facility stores...

From VS-07 to VS-06

Last week was busy with a number of electrical tests performed in two shifts. In practice it has been busier than anyone could have expected. Of course, electrical tests and the life of a team of more than 50 persons inevitably leads daily to a number of questions needing to be answered generally sooner than later. Our preparation was good enough to cover most of this. However, when postponement of the launch of four O3B satellites – originally planned for 30 September – was confirmed, adaption from all parties was necessary. We were originally assigned VS-07 (Vol Soyuz 7) and suddenly became VS-06. Just one digit change should not be dramatic but...