OrbitalHub

Credits: JAXA

HTV stands for H-II Transfer Vehicle. HTV is an unmanned spacecraft designed and built in Japan. HTV is designed to deliver supplies to the International Space Station (ISS).

The typical mission for HTV starts at the Tanegashima Space Center (TKSC) near Tsukuba, in Japan.

A H-IIB launch vehicle will inject the HTV on a low Earth orbit (LEO). After the separation from the H-IIB second stage, the transfer vehicle is able to navigate independently.

It will take approximately three days for HTV to reach the proximity of the ISS. During this time, it will maintain contact with the Control Center at TKSC (designated as HTV-CC) through the Tracking and Data Relay Satellite System (TDRSS). TDRSS is a network of satellites that allow a spacecraft in LEO to maintain permanent contact with the control center on the ground. HTV will use GPS to position itself at 7 km behind the ISS.

At this point, the berthing phase of the mission starts. HTV will approach the ISS within 500 m and use the Rendezvous Sensor (RVS) to move closer to the ISS. Reflectors that are installed on Kibo will allow HTV to maintain a distance of 10 m below the ISS.

Credits: JAXA

HTV does not have the capability to dock on its own to the ISS (as opposed to the European ATV), so the Canadarm2 robotic arm will be used to grab the transfer vehicle and berth it to the nadir side of the Node 2 module.

While the HTV is berthed to the ISS, supplies from the HTV’s pressurized section are transferred to the space station by the crew, and waste will be loaded from the ISS.

The cargo from the un-pressurized section will be unloaded using the robotic arm and attached either to the Exposed Facility of the Japanese Experiment Module (JEM) or the ISS Mobile Base System.

The HTV mission will end in a similar way to the European ATV: a destructive re-entry above the Pacific Ocean.

Here is some more background information about the HTV. The spacecraft is a cylinder-shaped structure 10 m long and 4.4 m in diameter. It has a total mass of 10,500 kg, of which 6,000 kg is cargo (divided into 4,500 kg pressurized cargo and 1,500 kg un-pressurized cargo). HTV can carry 6,000 kg of waste during the re-entry.

HTV consists of four modules: the Pressurized Logistics Carrier (PLC), the Unpressurized Logistics Carrier (UPLC), the Avionics Module, and the Propulsion Module. The UPLC carries the Exposed Pallet (EP), which can accommodate unpressurized payloads.

Credits: JAXA

The PLC is equipped with a Common Berthing Mechanism (CBM). This will allow the crew present on the station to enter the module in order to unload the supplies and load waste material.

The EP carried by the UPLC can be either Type I or Type III Exposed Pallets. The Type I EPs will carry payloads for the Kibo’s Exposed Facility (EF), while the Type III EPs will be used to deliver the Orbital Replacement Units (ORUs) to the ISS.

The systems in the avionics module enable HTV to execute the autonomous flight to the space station. The module also contains communication and power systems. The thirty-two thrusters installed on the propulsion module provide HTV with the capability to execute orbital adjustments and control the attitude during the mission.

HTV will add to the existing fleet of transfer vehicles that includes the Russian Soyuz and Progress spacecraft, as well as the European ATV. The first HTV mission is scheduled for late 2009.

For more information about HTV, you can visit the H-II Transfer Vehicle page on the JAXA web site.

Credits: ESA/NASA

Columbus is an integral part of the International Space Station (ISS), and it is the first European laboratory dedicated to long-term experimentation in zero-g conditions. The projected lifetime of the laboratory is ten years.

The laboratory is named after the famous Italian navigator and explorer Christoforo Columbus, who discovered the Americas in 1492.

The Columbus Laboratory is a large, pressurized aluminum cylinder measuring 4.5 meters in diameter and 6.9 meters in length. Its side walls contain eight research racks, with another two in the ceiling. Each one of these racks contains its own power and cooling systems. Video and data links systems feed information back to researchers and control centers on the Earth.

Columbus is the smallest ISS laboratory, but it has the same scientific, power, and data handling capacity as the other laboratories owned by Russia, USA, and Japan.

Credits: ESA/NASA

Scientific experiments started immediately on the Columbus because the laboratory arrived at the station with four scientific facilities pre-installed.

Columbus is used to carry out experiments in many different disciplines, including biology, biotechnology, fluid and material science, medicine, and human physiology.

The key element in these experiments is the micro gravity. In micro gravity, with gravitational forces much weaker than on the ground, processes that are obscured by gravity become noticeable. The research racks onboard Columbus are designed to investigate how micro gravity affects materials, biological specimens, and people.

Columbus contains the European Physiology Module Facility, the Fluid Science Laboratory, the BioLab, the Material Science Laboratory, and the European Drawer Rack, which can house a variety of small experiments.

Credits: ESA/NASA

Problems that are investigated on Columbus include the loss of bone cells by astronauts, plant growth in micro gravity, fluids behavior, and combustion of materials.

Experiments are also conducted outside of Columbus. These experiments are used to study the Earth or to expose materials to the harsh radiation, temperature, and the vacuum of space.

The mission that delivered the Columbus Laboratory to the ISS was STS-122. On February 7, 2008, the Space Shuttle Atlantis lifted off from Cape Canaveral, with Columbus docked into its cargo bay.

A vital part of the ISS and a prerequisite for the STS-122 mission, the Italian-built Node2 module (a.k.a. Harmony) was delivered to the ISS by the STS-120 mission in October 2007. The node is used as a connecting component for the Columbus Laboratory and the Kibo Laboratory. Node2 is also a docking port for the Space Shuttle.

Credits: ESA/NASA

Prior to the STS-122 mission , there were two spacewalks performed by the ISS Expedition 16 crew to prepare Node2 in order to receive the Columbus Laboratory.

ESA astronauts Léopold Eyharts from France and Hans Schlegel from Germany were members of the STS-122 mission. With five other NASA astronauts, they were part of the Columbus assembly and commissioning mission.

Schlegel spent twelve days in space and undertook two spacewalks to install the laboratory. Eyharts oversaw the installation and the start-up of the laboratory during a longer mission spent onboard the ISS.

Columbus was attached to the Harmony module on February 11, 2008, during the first spacewalk of the STS-122 mission. During this spacewalk, NASA astronauts Stanley Love and Rex Walheim spent nearly eight hours outside the ISS. The ISS robotic arm, Canadarm2, was used to move the laboratory from the cargo bay of the Space Shuttle to the starboard side of the Harmony module.

Credits: ESA/NASA

The second spacewalk of the mission lasted six hours and forty-five minutes. Schlegel and Walheim performed a regular station maintenance operation: they replaced the nitrogen tank that is used to pressurize the ammonia cooling system that runs on the ISS.

ESA was quite inspired to name the laboratory Columbus because it will open the world of micro gravity to a multitude of discoveries, in the same way that Christoforo Columbus opened up the New World to European explorers.