ATV simulation facility will be first to 'fly' very complex mission(Forwarded)

ESA News
http://www.esa.int

7 October 2003

ATV simulation facility will be first to 'fly' very complex mission

Before the green light can be given for the launch of Jules Vernes in autumn
2004, another Automated Transfer Vehicle (ATV) has to first successfully fly the
same mission.

Next year, prior to the inaugural ATV mission, this ATV will fly a full mission
through launch, docking and undocking from ISS, to controlled destructive
re-entry over the Pacific.

Although this ATV, which has been progressively assembled since late 2002, will
never go into space, or dock with ISS, or safely burn up during re-entry. In
fact, it will never move from its clean, air-conditioned room at EADS SPACE
Transportation’s facilities (ex-EADS-LV) in Les Mureaux, 50 km west of Paris,
France. Instead, it will be capable of simulating dozens of missions and it will
run hundreds of tests, including virtual failure scenarios.

The ATV mock-up does not even look like a full spacecraft; it is essentially the
electronic 'brain' and the 'nervous system' of the ATV with numerous electronic
boxes, powerful computers and huge networks of cables and wires. It is called
the Electrical Test Model (ETM), and it is able to replicate all the complexity
of the avionics and the onboard electronics of the ATV.

The Electrical Test Model is built into a large cylindrical structure, 4.8 m
diameter and 1.36 m in height. In the ATV flight model, the avionics bay segment
appears as a similar cylindrical white skirt between the two other main modules
of the ATV, the propulsion bay and the pressurized integrated cargo carrier.

Simulation of mission scenarios

To simulate all the phases of the mission, the Electrical Test Model is at the
heart of an even larger piece of ground equipment, the Functional Simulation
Facility (FSF), which includes up to 50 electronics racks. Through hundreds of
cables and umbilicals, dozens of ground computers, controlled by some 50
engineers, are able to replicate the functional environment of the navigation
and flight dynamics during all possible nominal and off-nominal scenarios of the
spaceship.

In addition, key elements of the real flight hardware, like, for example, the
GPS or the rendezvous videometre -- which enables laser-guided rendezvous
operations in orbit -- will be inserted in the Functional Simulation Facility
for dedicated tests. These hardware elements can be compared to the navigation
'senses' of the ATV mock-up, connected -- through 'nervous system' like cables
-- to the electronic 'brain'. Thanks to this complex infrastructure, with its
interconnecting flight hardware, powerful computers and numerous pieces of
software, it is as if the avionics bay Electrical Test Model is actually flying
in orbit.

Three types of ATV simulation test

The Functional Simulation Facility is also able to simulate the behaviour of
onboard equipment and to check their performance during all flight phases. The
Functional Simulation Facility also enables switching between software and
hardware models. One of the key elements of the Functional Simulation Facility
is the Numerical Simulator whose powerful calculator is able to electronically
introduce hardware or software failures.

This state-of-the-art simulator allows three kinds of critical tests:

* Electrical tests to check the compatibility of all of the ATV components,
subsystems and interfaces,

* Functional tests to control the response of the hardware, including several
flight hardware systems, to the ATV Flight Application Software (FAS) inputs,

* Full "close-loop" mission tests, which are expected to run fully next spring
2004, with all the hardware, the full and final version of the flight software
(FAS) and all the means to simulate the navigation: from virtual jet firings to
simulated spacecraft movements, providing calculated stimulation to all
navigations sensors like, for example, the star tracker or the accelerometer.

Simulation facility nearing completion

"At this stage of the simulator test campaign, about 90% of all the equipment of
the Functional Simulation Facility and Electrical Test Model is assembled and
integrated. A few elements, like the Russian Equipment Control System (RECS),
are yet to be delivered," said Nicolas Bouge, coordinator of ATV qualification
tests at EADS SPACE Transportation.

Built by RSC Energia, near Moscow, the RECS will be located in the Cargo Carrier
segment of the ATV. The RECS controls all the mechanical Russian docking systems
during rendezvous, as well as the refuelling operations during the attached
phase. It is also the electrical interface with the International Space Station,
allowing power transfer from the Station to the ATV if needed.

The Functional Simulation Facility will also be permanently equipped with a full
scale copy of the Russian ATV docking mechanism which has to be integrated and
tested in the facility. Arrival of the Russian Docking System (RDS) mock-up is
expected by mid-November.

Related articles

* First rendezvous simulation: a major step for ATV
http://www.esa.int/esaHS/SEM60A1P4HD_index_0.html
* Successful design review: ATV gets go-ahead
http://www.esa.int/esaHS/SEM847T1VED_index_0.html
* Jules Verne: the first and most elaborate space rendezvous for Europe
http://www.esa.int/esaHS/SEMJXMS1VED_index_0.html
* CNES to run ATV Control Centre under ESA contract
http://www.esa.int/esaHS/SEMC9IR1VED_index_0.html
* ESA signs contract with CNES for Automated Transfer Vehicle Control Centre
http://www.esa.int/esaHS/SEMCPB5V9ED_index_0.html
* ATV mission scenario -- picture report
http://www.esa.int/esaHS/ESA2NSF18ZC_iss_0.html

Related links

* ATV homepage
http://www.esa.int/spaceflight/atv

IMAGE CAPTIONS:

[Image 1:
http://www.esa.int/export/esaHS/SEMK..._index_1.html]
Since mid-September, the ATV simulation facility, which combines the Electrical
Test Model and the Functional Simulation Facility, runs two eight-hour shifts,
five days a week with the help of a team of 50 engineers.

Credits: ESA/EADS, S. Corvaja 2003

[Image 2:
http://www.esa.int/export/esaHS/SEMK...html#subhead1]
This wide angle shot shows ESA and EADS engineers inside the ETM avionics bay
mock-up inside the clean air-conditionned room building, at EADS SPACE
Transportation's facilities (ex-EADS-LV) in Les Mureaux, 50 km west of Paris.

Credits: ESA/S. Corvaja

[Image 3:
http://www.esa.int/export/esaHS/SEMK...html#subhead2]
The International Space Station (ISS) depends on regular deliveries of
experimental equipment and spare parts as well as food, air and water for its
permanent crew. From Autumn 2004 onward, Europe's Automated Transfer Vehicle
(ATV) will be one of the indispensable ISS supply spaceships.

Credits: ESA/Ducros