ATV

ATV Activities Lamp'n
200 N Thruster Valve
ATVSim
Bipropellant Thrusters

ATV Description

Comparison
ATV - Progress - Apollo

ATV Propulsion
System Schematic

A video clip of ATV propulsion during
hot-fire testing is provided in the
Video Library

ATV Factsheet

Astrium Bipropellant
Thrusters

10 N Thruster
200 N ATV
400 N Apogee Engines
500 N EAM
Thruster Range

Automated Transfer Vehicle Propulsion

220 N bipropellant attitude control and braking thruster

ATV: 200 N Thruster Clusters

Commencing in March 2008, the Automated Transfer Vehicle will deliver its 45 m³ pressurised module containing up to 7.2 tonnes of equipment, fuel, food, water and air for the crew of the International Space Station (ISS). This, the maiden flight of ATV has been named ‘Jules Verne’ and a further 7 ATV's have been planned for resupplying the ISS every 15 months.

Currently, about 1,500 people in different European countries are working on this €900-million ESA programme.

As its name implies, the ATV is a truly automated vehicle. It can navigate and safely dock to the station and accomplish its mission without any human intervention whatsoever. The ATV is therefore the first fully automatic resupply spacecraft of its kind. Such autonomy, together with fault tolerance requirements, imposes about one million lines of software code for the various onboard computers.

The ATV will be launched on an ES ATV version of Ariane 5, which will place the spaceship into a 260 km circular low Earth orbit inclined to 51.6°. From this orbit, the ATV will use its own propulsion system to automatically navigate to, and dock with, the Space Station.

ATV Propulsion System
The ATV propulsion system is contained in the unpressurised Service Module, located aft of the habitable Pressurised Module. The Service Module also contains electrical power, computers, communications and avionics.

Credits: ESA/A. van der Geest ATV Service Module

The bipropellant propulsion system is pressure fed with the propellant combination monomethyl hydrazine fuel and nitrogen tetroxide oxidiser. The main elements of the ATV propulsion being:

4 x 490 N main navigation engines
28 x 220 N attitude control and braking thrusters.
8 titanium propellant tanks of 7 tonnes capacity.
2 high pressure carbon fibre-wound helium pressurant vessels.

In brief, the bipropellant propulsion system is designed to perform:

		Navigation to the International Space Station (ISS), after separation from Ariane 5.
		Automatic manoeuvres for rendezvous and docking to the ISS.
		While docked, the ATV will perform ISS attitude control, debris avoidance manoeuvres and raising of the 183 tonne station's orbit to overcome the effects of atmospheric drag.
		After 6 months, de-docking and automatic departure manoeuvres.
		Navigation to the orbital deorbitation point.
		Retroburn and de-orbitation manoeuvres.

From the 7 tonnes of available propellant, approximately 2.3 tonnes is available for free flight manoeuvres and approximately 4.7 tonnes is available for manoeuvring the space station at intervals of 10 to 45 days.

In the event of a thruster, or main engine failure, redundant branches and control electronics are used to switch propulsive functions to fulfil operational objectives and safety requirements.

The scale of ATV, together with the complexity of propulsive manoeuvres and proximity to man, results in a propulsion subsystem that is one of the largest and most sophisticated ever built. In fact, the internal volume of the complete ATV is sufficient to accommodate a double-decker London bus.

The entire propulsion system in nominal and failure mode can be simulated using ATVSim. Using this software, the simulation process can be accomplished significantly faster than in real-time.

200 N Attitude Control and Braking Thrusters
Development of the 200 N Attitude Control and Braking Thruster have been entrusted to the propulsion specialists at Astrium Lampoldshausen.

A total of 28 x 200 N thrusters are used on ATV, located thus:

Fwd: 4 clusters of 2 thrusters
Aft: 4 clusters of 5 thrusters

The thruster clusters (shown in the figure top right), deliver both steady state thrust and impulse bit and can also be used as back-up in the event of main engine failure.

Safety and redundancy are major design drivers and each thruster is equipped to measure and detect malfunctions and problems by continuously measuring chamber temperature and combustion pressure.

Astrium Lampoldshausen are also responsible for the production, integration and acceptance testing of:

ATV propulsion module pressure control assemblies (PCA)
Propellant Isolation Assembly (PIA)
Propulsion system qualification

200 N Thruster Development Activities
The ATV's 220 N thruster continues to be successfully developed by the Astrium team at Lampoldshausen. The thruster has been designed and developed in accordance with the special ATV requirements, as shown in the table below:

Showerhead Injector
The showerhead injector is derived from the 400 N thruster that has a highly reliable space proven heritage dating back to 1974. During that time, the thruster has achieved 100% mission success, having been used on numerous GTO spacecraft and demonstrating a 14-year service life on NASA's interplanetary Galileo mission. This robust thruster has proven to yield the following advantages:

High combustion efficiency
Wide operating box with flat performance behaviour
Easy, cost effective manufacturing

The implementation of the 400 N showerhead injector into the 200 N thruster for ATV has led to very satisfactory results.

200 N thruster Qualification Box
The complete Qualification Box has been demonstrated and the thruster performance (ISP, c*), measured thus:

200 N Thruster Qualification Box				200 N Thruster Hot Firing

The 200 N thruster performance over the whole box has shown a very flat behaviour with an Isp well above 280 s, as specified for the whole mass flow regime.

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