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03-5-09

HTV

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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.

 

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01-8-09

Taurus II and Cygnus

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Credits: NASA

 

Orbital will employ its Taurus II medium-lift launch vehicle and the Cygnus spacecraft in order to service the International Space Station (ISS) under the Commercial Resupply Services (CRS) contract.

 

Orbital is one of the two companies awarded CRS contracts under the Commercial Orbital Transportation Services Project (COTS).

 

 

NASA announced the COTS project on January 18, 2006. The purpose of the program is to stimulate the development of access to low Earth orbit (LEO) in the private sector. At the time, with the imminent retirement of the Space Shuttle fleet, NASA was faced with the option of buying orbital transportation services on foreign launch systems: the Russian Soyuz / Progress, the European Ariane 5 / ATV, or the Japanese H-II / HTV.

 

Another factor taken into consideration by NASA was that competition in the free market could lead to the development of more efficient and affordable launch systems compared to launch systems that a government agency could build and operate.

 

Credits: Orbital

 

Orbital relies on proven experience in launch vehicle technology. Taurus II is designed to provide low-cost and reliable access to space, and it uses systems from other members of Orbital’s family of successful launchers: Pegasus, Taurus, and Minotaur.

 

Taurus II is a two-stage launch vehicle that can use an additional third stage for achieving higher orbits. The payloads handled by Taurus II can have a mass of up to 5,400 kg.

 

Orbital is responsible for overall development and integration of the first stage. The two AJ26-62, designed and produced by Aerojet and Orbital, are powered by liquid oxygen and kerosene. The core design is driven by NPO Yuzhnoye, the designer of the Zenit launchers.

 

The AJ26-62 engines are basically the NK-33 engines designed by the Kuznetsov Design Bureau for the Russian N-1 launch vehicle, and remarketed by Aerojet under a new designation.

 

 

The second stage uses an ATK Castor-30 solid motor with thrust vectoring. This stage evolved from the Castor-120 solid stage.

 

The optional third stage is developed by Orbital. The stage was dubbed the Orbit Raising Kit (ORK) and it uses a helium pressure regulated bi-propellant propulsion system powered by nitrogen tetroxide and hydrazine. ORK evolved from the Orbital STAR Bus. Because it is a hypergolic stage, it allows several burns to be performed in orbit, and can be used for high-precision injections using various orbital profiles.

 

Credits: Orbital

 

Cygnus will only have cargo capability and will be able to deliver up to 2,300 kg of pressurized or un-pressurized cargo to the ISS. The spacecraft will also be able to return up to 1,200 kg of cargo from ISS to Earth.

 

The two components of the Cygnus spacecraft will be the service module and the cargo module.

 

The service module is based on the Orbital STAR bus (like the ORK stage), and will use two solar arrays for producing electrical power for the navigation systems onboard.

 

The pressurized cargo module is based on the Italian-built Multi-Purpose Logistics Module (MPLM). The un-pressurized cargo module is based on NASA’s ExPRESS Logistics Carrier.

 

 

Cygnus will not dock to the ISS in the same manner as the European ATV, but it will be able to maneuver close to the ISS where the Canadarm 2 robotic arm will be used to capture it and berth it to the Node 2 module, similar to the Japanese HTV or SpaceX’s Dragon spacecraft.

 

The Mid-Atlantic Regional Spaceport (MARS), located at NASA’s Wallops Island Flight Facility on Virginia’s Eastern shore, was chosen by Orbital to serve as the base of operations for the Taurus II launch vehicle.

 

MARS has two FAA licensed launch pads for LEO access. MARS also offers access to suborbital launchers, vehicle and payload storage, and processing and launch facilities.

 

Credits: NASA

 

Due to the location of the spaceport, latitude 37.8 degrees N, longitude 75.5 degrees W, optimal orbital inclinations for the launches performed at MARS are between 38 and 60 degrees. Polar and retrograde orbits can also be serviced with additional in-flight maneuvering.

 

The first flight of Orbital’s new Taurus II / Cygnus launch system under COTS is scheduled for late 2010.

 

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11-22-08

ESA Prepares For The Next Step

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Credits: ESA

 

The European presence in space has become more prominent over the years. The development of the Columbus Laboratory and the introduction of the Automated Transport Vehicle (ATV) are two major milestones that have opened a new era for Europe’s presence in space.

 

Europe now aspires to consolidate its independence with the Large Cargo Return (LCR) and the Crew Transport Vehicle (CTV).

 

 

The LCR and the CTV are the new versions of the ATV that are now being considered by ESA’s Human Spaceflight Directorate. These versions of the ATV reuse the service module of the ATV configuration. A capsule with re-entry capability will replace the integrated cargo carrier. In the first phase, the capsule will bring cargo from the ISS down to Earth. The ultimate goal is to be able to carry a full crew up to the ISS and bring the crew back to Earth.

 

Credits: ESA

 

Atmospheric re-entry is not a new challenge for ESA engineers.

 

Past programs – like the Atmospheric Re-entry Demonstrator – and future programs – like the Intermediate Experimental Vehicle (IXV) – will help validate models used for the simulation of the re-entry phase and also provide a solid base in designing materials for the thermal protection system.

 

 

However, one challenge that needs to be addressed is the ejection system for the CTV/Ariane V configuration. The safety of the crew has to be ensured in the case of an anomaly on the launch pad or during the ascent phase of the flight. ESA will have to develop new technologies to satisfy this crucial requirement.

 

Credits: ESA

 

ESA has already proposed the LCR and the CTV versions of the ATV as the next step in the evolution of the ATV. However, the decision to go forward lies with the Council of the European Space Ministers. If ESA proposals are approved, the first flight of the LCR is expected in 2015, and the CTV could be docking to the ISS by 2020.

 

Check out ESA’s podcast about the new proposed programs that are based on the ATV.

 

 

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Credits: NASA

 

The Multi-Purpose Logistics Module (MPLM) is a pressurized module that is used on Space Shuttle missions to transfer cargo to and from the International Space Station (ISS).

 

A typical MPLM mission starts in the cargo bay of a Space Shuttle. The MPLM is carried to the ISS and berthed to one of the docking modules by the Canadian robotic arm. The supplies are offloaded and then finished experiments and waste are loaded on to the module. At the end of the mission, the MPLM is moved to the Space Shuttle cargo bay and returned to Earth.

 

The Italian Space Agency (ASI) provides the modules to NASA. Three MPLMs have been built and delivered to NASA thus far. NASA owns the MPLMs and ASI receives research time on ISS in exchange. The MPLMs were named after great figures in Italian history: Leonardo, Raffaello, and Donatello. However, some of the mission badges display the ninja turtles instead.

 

 

The construction of the first MPLM – Leonardo – began in April 1996. Leonardo was delivered to NASA in August 1998. Raffaello and Donatello followed in August 1999 and February 2001, respectively. Each MPLM can make 25 return trips to space.

 

Credits: NASA

 

The MPLM is 6.4 meters long and 4.6 meters in diameter. The module weighs 4.5 tons and it can deliver up to 10 tons to the ISS. The design of the module resembles the payload module that is part of the ATV. In addition, ATV has a service module that offers autonomy. Obviously, ATV was the direct beneficiary of the knowledge gained during the design and operational phases of the MPLM.

 

 

There is room for sixteen standard payload racks (International Standard Payload Racks – ISPR) in the MPLM. Even if it is not used to carry a human crew, MPLM has its own life-support system. Furthermore, it has a 3 KW internal power supply.

 

Credits: NASA

 

The current Space Shuttle mission – STS 126 – has delivered the MPLM Leonardo to the ISS. Leonardo is on its fifth spaceflight and hauled over 14,000 pounds of supplies and equipment to ISS.

 

Part (a small part) of the payload was turkey, candied yams, stuffing, and dessert for a Thanksgiving meal at the station.

 

 

A special piece of equipment, the GLACIER, was also delivered to the station. GLACIER stands for General Laboratory Active Cryogenic ISS Experiment Refrigerator. GLACIER is a double locker cryogenic freezer that will be used for transporting and preserving science experiments. The payload also included a galley for the Destiny laboratory, an advanced Resistive Exercise Device (aRED), and two new crew quarter racks for the expanded station crew.

 

Credits: NASA

 

There are two more MPLM missions scheduled before the Space Shuttle retires. STS-128 will carry Leonardo in July 2009, and Raffaello will be docked to ISS during the STS-131 mission in February 2010.

 

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We covered the ATV Jules Verne mission in a previous post (Jules Verne close to the End of its Space Journey) and mentioned that the typical ATV mission ends with a destructive re-entry above the Pacific Ocean. We come back with this post to present the conclusion of the ATV mission.

 

Credits: NASA

 

The ATV separated from the International Space Station (ISS) on September 5, 2008, filled with more than 2 tonnes of waste. The ATV undocked from the aft port of the Zvezda Service Module and it was placed in a parking orbit for three weeks. While being parked, a series of tests of the guidance and control systems were performed.

By carrying out re-phasing maneuvers, the ATV positioned itself to a predefined position behind and underneath the ISS. In this way, the crews from the ISS and from two specially equipped observation planes in the skies of the South Pacific were able to view and to record the re-entry.

 

Credits: NASA

 

The re-entry was initially modeled on computer in order to anticipate the trajectory and the location of the area where the breakout fragments of the spacecraft will fall. The observations helped determine if the re-entry matched the computer modeling.

 

As planned, the first ATV mission concluded on September 29, 2008, when two engine burns de-orbited the spacecraft. ESA scheduled the re-entry on this date because the lighting conditions were appropriate for an imagery experiment and the breakup happened at approximately 75 km above the waters of the Pacific Ocean. The remaining fragments fell into the Pacific some 12 minutes later.

 

Credits: ESA

 

This first mission proved the logistical value of the ATV. The delivery of 6 tonnes of cargo to the ISS, the automatic rendezvous and docking capabilities, the attitude control maneuvers performed, they all show how far the European space capabilities have developed.

 

ESA engineers are already working on the next two ATV spacecrafts. The next ATV mission is scheduled for 2010 and there are many proposals to adapt the ATV to other types of missions.

 

Credits: ESA

 

One important variation of the typical ATV mission is the Large Cargo Return (LCR). The LCR configuration will consist of a large cargo capsule capable of bringing back on Earth hundreds of kilograms of cargo and valuable experiment results. LCR would be able to dock to the US side of the ISS that has larger docking ports and would make possible the transfer of complete payload racks.

 

The video showing the destructive re-entry of Jules Verne is available on the ESA website.

 

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Credits: ESA

 

In September 2008, the first Automated Transport Vehicle (ATV) mission will come to an end. It is a significant achievement for the European space industry, marking another first in space exploration: the ATV spacecraft is capable of performing rendezvous and docking procedures to the International Space Station (ISS) in a fully autonomous manner. In comparison, the Russian spacecrafts used for carrying supplies and crews to the station (Progress and Soyuz) need the cooperation of the station for docking procedures.

 

The ATV program started back in 1995 and it has so far cost approximately 1.3 billion euros.

 

 

I will start by presenting some of the technical data of the ATV spacecraft. It will not be an exhaustive presentation by far, but I think it is important to have the orders of magnitude at least.

 


Credits: ESA

 

ATV has a mass of almost 21 tonnes (20,750 kg) at launch, of which up to 7 tonnes is on-board propellants and payload. The pressurized cabin section used for cargo storage has 48 cubic meters in volume. ATV is the largest spacecraft ever developed in Europe.

 

In the on orbit configuration, the spacecraft has a length of 9.794 m, maximum diameter of 4.480m, and the solar arrays span of 22.281 m.

 

The launch vehicle used by ATV missions is Ariane 5. The ATV is deployed by the Ariane 5 rocket on a low Earth orbit (260×260 km, inclination 51.6 degrees).

 


Credits: ESA

 

The ATV spacecraft consists of two main modules, the avionics/propulsion module, called the ATV Service Module, and the Integrated Cargo Carrier (ICC), which docks with the International Space Station (ISS).

 


Credits: ESA

 

The ICC represents 60% of the total ATV volume. It is used to deliver two types of supplies to the ISS: the dry cargo (like hardware and personal parcels) and the fluid cargo (like propellant for the ISS’s own propulsion system, water, and gas).

 

Cargo mass can be distributed as follows:
· dry cargo: 1,500 kg – 5,500 kg;
· water: 0 – 840 kg;
· gas (nitrogen, oxygen, air, 2 gases/flight): 0 – 100 kg;
· ISS re-boost and attitude control propellant: 0 – 4,700 kg;
The total cargo upload capacity: 7,667 kg.

 


Credits: ESA

The waste download capacity is 6,340 kg (5,500 kg dry cargo + 840 kg wet cargo).

 

The front of the ICC contains the docking system. The docking system is Russian made and it is a state-of-the-art docking mechanism. It has evolved over the years from the original docking system used for the Salyut space station program in the late 1960s. The docking system enables crew access to the ICC pressurized module, but also provides electrical and propellant connections between the ATV and the ISS.

 

 

In order to make docking a safe procedure, the ICC is equipped with quite an impressive array of sensors and active components: two telegoniometers (used to calculate the distance and direction from ATV to ISS), two videometers (used to compute distance and orientation of the ISS), two star trackers, and two visual video targets (used by the ISS crew to monitor visually the ATV’s final approach).

 


Credits: ESA

The ATV Service Module includes the propulsion systems, the electrical power, computers, the communications, and the avionics.

 

The main propulsion system of the spacecraft is comprised of 4 x 490 N thrusters. The attitude control system relies on 28 x 220 N thrusters. The ATV propulsion system is a pressure fed liquid bi-propellant system using monomethyl hydrazine fuel and nitrogen tetroxide oxidizer. The fuel is pressurized by helium stored in two high pressure tanks.

 

The four solar panels ATV is equipped with can generate 4,800 W on average during the 6 month mission in space.

 

The typical ATV mission starts in French Guiana, at the Kourou launch site. An Ariane 5 rocket deploys the ATV spacecraft on a circular Low Earth Orbit (LEO) at an altitude of 260 km. ATV then activates its navigation systems and fires its thrusters to reach the transfer orbit to the ISS.

 

 

After two or three days, and raising its orbit to 400 km, ATV will be in sight of ISS. It will start the approaching phase of the mission from about 30 km behind and 5 km below the station.

 

Even if the approach and the docking procedures are fully automatic, the flight controllers can at any time call on the spacecraft and back away from the station. The ISS crew can also reject the spacecraft in case any anomalies are noticed.

 

Once the spacecraft is safely docked to the ISS, the station’s crew can access the pressurized cargo section and remove the payload. After the payload is removed, the crew fills the cargo section with used hardware and waste materials.

At intervals of 10 to 14 days, the main thrusters of the ATV will be used to boost the station’s altitude.

Once the mission is accomplished, the ATV separates from the ISS, and performs a controlled and safe destructive re-entry somewhere above the Pacific Ocean.

 

The first ATV mission is called Jules Verne, after the French author Jules Gabriel Verne (1828 – 1905) who pioneered the science-fiction genre.

The Jules Verne ATV had to pass many tests in order to qualify for the mission. An interesting test was the acoustic testing at the ESA’s test facilities in Noordwijk in the Netherlands.

The spacecraft has to withstand the vibrations caused by the extreme noise levels generated during the launch by the Ariane 5 rocket. The ATV was locked in a closed space with huge speakers that simulate the noise levels recorded during an Ariane 5 launch.

 


Credits: ESA

Even though the ATV is able to perform the rendezvous and the docking procedures on its own, the ground control experts from ESA and CNES, the French space agency, were involved in the operations. They determined the route the spacecraft must follow in order to dock with the ISS. The two ISS control centers were also involved in ATV operations: the Mission Control Centre in Moscow and the Mission Control Center in Houston, Texas.

 

 

The Jules Verne mission is the first in a series to come. There are already five ATV missions scheduled between now and 2015. Under the coordination of ESA and the prime contractor EADS Astrium, European engineers have contributed to this new generation spacecraft. Major sub-contractors are Thales Alenia Space (Italy), Astrium (Germany and France), Oerlikon Space (Switzerland), Dutch Space (The Netherlands), with Russian partners providing the advanced docking system.

 

 

The Jules Verne mission liftoff occurred on March 9th, 2008 at 05:03 CET (04:03 UT) at the Kourou Spaceport in French Guiana.

 

ATV Jules Verne had to perform what the media called orbital rehearsals for ISS docking. The initial test, performed on March 14th, demonstrated the Collision Avoidance Manoeuvre (CAM). During this initial test, an automated system took control of the spacecraft and moved it to a safe distance from the ISS.

 

 

The following two tests demonstrated the flying capabilities of the spacecraft in the proximity of the station. On March 29th, ATV manoeuvred around the ISS using relative GPS navigation. Two days later, the ATV tested close proximity manoeuvring and control. The ATV approached first within 20 meters of the station, retreated, then approached even nearer, to only 12 meters from the docking port on the ISS Russian Zvezda module, before again backing off to a safe distance from the station.

 

On April 3rd, 2008 ATV Jules Verne docked to the ISS.

The ATV will undock from the ISS at the beginning of September 2008 and it will complete its mission at the end of September 2008 above the Pacific Ocean.

 

Due to its remarkable capabilities, ATV will serve the ISS for many years and it will become a major player after the Space Shuttle retirement in 2010.

 

There are quite a few ATV evolution scenarios already considered by ESA in the present. To mention here only two of the configurations: the Large Cargo Return (LCR) and the Crew Transport Vehicle (CTV). The LCR configuration presents a large cargo re-entry capsule able to bring back hundreds of kilograms of cargo and valuable experiment results. In the CTV configuration, the Integrated Cargo Carrier component of the spacecraft would be transformed into a manned re-entry capsule for crew transportation. Because of the re-entry capabilities, the CTV could be used as a crew rescue capsule for the ISS.

 

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