European Space Agency ATV-3 Mission to ISS Delayed to Late March

Integrated Cargo Carrier (ICC) in Bremen, Germany Image Credit: ESA

Loading Cargo Aboard the ICC on the Edoardo Amaldi (ATV-3) Image Credit: ESA

The scheduled launch of the European Space Agency’s (ESA) third resupply mission to the International Space Station (ISS), will be moved from 9 March 2012 to the 22-23 March time frame. A strap securing the cargo in the ICC (upper right) has become loose, and engineers will have to access the interior of the vehicle in order to reconnect the strap. The launch had been scheduled for 3:05 Phoenix time (10:05 UTC) from Kourou, French Guiana. The ATV-3 Edoardo Amaldi will deliver 4,395 kg of propellant, oxygen, air and water to the Station. The ICC will deliver 2,450 kg of dry cargo, for a total of 6,845 kg. Previously, the Johannes Kepler (ATV-2) carried 6,600 kg of fuel and cargo to the ISS. The launch was on 15 February 2011, and docking occurred on 26 February 2011. The first ATV – the ATV-1 Jules Verne – flew on 9 March 2008, and docked on 3 April. The Edoardo Amaldi will carry a total of 6271 kg of fuel. The ATV will consume 2,200 kg on the spacecraft’s journey to the ISS, and for the de-orbit burn. Attitude control and several re-boost burns during the six month stay will use an additional 3,000 kg. The remaining 860 kg will be transferred to the Russian portion of the International Space Station for later maneuvering. Below is a cutaway view of an Automated Transfer Vehicle illustrating the main components of the spacecraft. The launch will be carried live by ESA television at http://television.esa.int/ Cutaway View of the ESA Automated Transfer Vehicle (ATV) Image Credit: ESA

ATV-2 Johannes Kepler

ATV-2 Johannes Kepler Image Credit: European Space Agency (ESA)

Keeping the International Space Station supplied will become an increasing challenge with the retirement of the US Space Shuttle in 2011. The Japanese were schedule to launch their second H-II Transfer Vehicle (HTV-2) resupply mission today, 20 January, but weather has caused the mission to be rescheduled for a possible launch on Saturday. The Russians fly their Progress spacecraft on resupply missions, and the next one is scheduled for 28 January. Finally, the European Space Agency (ESA) has flown their Automated Transfer Vehicle once before (ATV-1 or Jules Verne) on 9 March 2008 and their next launch is coming up on 15 February 2011.

The 20 ton Johannes Kepler ATV has a cargo capacity of up to 7 metric tons. The composition of this load can vary depending on the mission: 1.5 to 5.5 metric tons of freight and supplies (food, research instruments, tools, etc.) up to 840 kilograms of drinking water up to 100 kilograms of gases (air, oxygen and nitrogen) up to four metric tons of fuel for orbit correction and up to 860 kilograms of propellant to refuel the space station. The spacecraft is compose of two main sections. The first is the ATV Service Module (below, left), which is not pressurized, includes propulsion systems, electrical power, computers, communications and most of the avionics. The ATV uses four main engines and 28 small thrusters to control the navigation of the spacecraft. Four solar panels are deployed after launch and supply 4800 Watts of power to the batteries and the electrical systems. The second component is the Integrated Cargo Carrier (below, right). The large section in the front is pressurized and comprises about 90% of the cargo volume. It handles all the dry cargo, including the racks on each side. The inhabitants of the International Space Station access this area through the hatch in the Russian docking system.

ATV Service Module & Four Main Engines Image Credit: ESA

Cutaway of ATV Cargo Carrier Image Credit: ESA

The Equipped External Bay of the Integrated Cargo Carrier (ICC) holds 22 spherical tanks of different sizes and colors. These tanks are used to re-supply the Station with propellant for the International Space Station propulsion system, various gases (air, oxygen, and nitrogen) and water for the crew. The contents of these tanks are delivered to the Station through dedicated connections, or through manually operated hoses.

ATV Liquid Resupply Tanks Image Credit: ESA

Russian Docking Module Image Credit: ESA

The ATV uses the Russian-made docking equipment sensors to perform the approach and docking sequence. The procedure is the same as with the Soyuz manned capsules and the Progress resupply spacecraft. The Russian docking system enables physical, electrical and propellant connections with the Station. Access to the ICC is through the Russian hatch. Once the ATV is securely docked, the crew can enter the cargo section and remove the payload, which usually includes maintenance supplies, science hardware, parcels of fresh food, mail and family tapes or DVDs.