External Tank Laboratory

External Tank Laboratory

The External Tank Laboratory as seen from Space Shuttle Liberty on 30 July 2010 during STS-14W.
Station statistics
NSSDC ID:	2010-099A
Call sign:	Echo
Crew:	6
Launch:	2010-2011
Launch pad:	MPLC LC-1, KSC LC-39
Perigee:	336 km altitude (220 nmi)
Apogee:	346 km altitude (230 nmi)
Orbit inclination:	51.64 degrees
Average speed:	7,706.6 m/s (27,743.8 km/h, 17,239.2 mph)
Orbital period:	c. 93 minutes
Days in orbit:	5688 (5 December)
Days occupied:	5688 (5 December)
Number of orbits:	c. (5 December)
Orbital decay:	2 km/month
Statistics as of 27 November 2010 (unless noted otherwise)
Configuration

The External Tank Laboratory (ETL) is a research facility that is being assembled in low Earth orbit by the International Space Agency. On-orbit construction of the station began in 2010 and is scheduled for completion by late 2011. The station is expected to remain in operation until at least 2025, and likely 2030. With a greater cross-sectional area than that of any previous space station, the ETL can be seen from Earth with the naked eye, and is by far the largest artificial satellite that has ever orbited Earth. The ETL serves as a research laboratory that has a microgravity environment in which crews conduct experiments in biology, chemistry, medicine, physiology and physics, as well as astronomical and meteorological observations. The station provides a unique environment for the testing of the spacecraft systems that will be required for future missions to the Moon and outer Solar System.

Purpose

The External Tank Laboratory (ETL) is an internationally developed satellite currently being assembled in Low Earth Orbit. Primarily a research laboratory, the ETL offers an advantage over spacecraft such as NASA's Space Shuttle because it is a long-term platform in the space environment, where extended studies are conducted. The presence of a permanent crew affords the ability to monitor, replenish, repair, and replace experiments and components of the spacecraft itself. Scientists on Earth have swift access to the crew's data and can modify experiments or launch new ones, benefits generally unavailable on specialised unmanned spacecraft. Following the addition of the Centrifuge Accommodations Module, crews can now expose experiments to varying amounts of gravitation in an environment unavailable to ground based researchers. The ETL also plays host to crews from various international agencies, and is also a destination for space tourists.

The ETL serves as a test platform for orbital construction techniques and for research into the effects of long-term exposure to microgravity on the human body, the understanding of which will be essential for future long duration missions beyond the Earth-Moon system. The use of spent external tanks, and the ability to recycle a large number of consumables comprise some of the techniques learned aboard the station.

Origins

Interior view of the liquid hydrogen tank found on a Space Shuttle External Tank. Note the two men standing inside for scale.

Station structure

Pressurized modules

Module	Assembly mission	Launch date	Launch system	Nation	Isolated View
External Tank Laboratory (ETL-ACC)	ECF1	10 May 2010	Space Shuttle Liberty, STS-12W	USA
	The initial component of the station, the ET used to launch STS-20W was converted into a wet workshop. The initial launch carried the ET itself, an Aft Cargo Carrier containing outfitting equipment, temporary solar panels and radiators for the station, and stabilization thrusters. The ET's hydrogen tank serves as the crew's main living quarters, and contains the life support equipment and experiment space. The oxygen tank used as storage space.
Clarity (Node 1)	ECF3	26 August 2010	Space Shuttle Liberty, STS-17W	USA
	The first of the station's node modules, Clarity is the utility hub of the ISS. The module contains four racks that provide electrical power, bus electronic data, and acts as a central connecting point for several other components via its six Common Berthing Mechanisms (CBMs). The Rafaello Pressurized Multipurpose Module, Venture airlock and Centrifuge Accommodations Module are permanently berthed to the module. In addition, the module connects to both the External Tank Laboratory (via PMA-1), and the Discovery laboratory.
Cupola	ECF3	26 August 2010	Space Shuttle Liberty, STS-17W	Europe (Builder) USA (Operator)
	The Cupola is an observatory module that provides ETL crew members with a direct view of docked spacecraft and exterior operations, as well as an observation point for watching the Earth. The module comes equipped with robotic workstations for manual spacecraft docking in an emergency and shutters to protect its windows from damage caused by micrometeorites.
Venture (Airlock)	ECF4	25 October 2010	Space Shuttle Liberty, STS-20W	USA
	The primary airlock for the ETL, Venture hosts spacewalks with both US EMU and Russian Orlan spacesuits. Venture consists of two segments; the equipment lock, that stores spacesuits and equipment, and the crew lock, from which astronauts can exit into space. Exterior storage points also provide locations for storing and refilling up to four MMUs when not in use.