OrbitalHub

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.

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.