Antares, International Rocket for an International Station

One of the two rockets being put to use these days in resupplying the International Space Station is the Orbital Sciences Antares, named for a star in the constellation Scorpius. Antares is a two-stage rocket intended to carry the Cygnus resupply vehicle (a more detailed post can be written about that if there's interest).

Antares is a multinational project, assembled from components built in 4 different countries on 3 continents, which is incredibly appropriate for a vehicle intended to resupply an international scientific outpost. So let's check out the parts from the bottom up:


 AJ-26 Rocket Engines - The part that really makes the thing get up and go! Antares has two of them and when they were originally built they were called NK-33's. These engines have a pretty interesting history because they were built in the late 1960s. 
By the Kuznetsov Design Bureau. 
In the Soviet Union. 
For the N1...their MOON ROCKET!

That rocket was unsuccessful overall but these engines were so advanced at the time that they're still up to modern performance standards with some relatively minor upgrades from the Aerojet Rocketdyne company in California, who has a large enough stock of those motors to supply the Antares for all eight contracted flights to the ISS with some to spare. Antares has two engines that are gimballed, meaning they're mounted in a way that they can be tilted to steer the rocket.

First Stage Fuel Tanks & Structure - The bulk of the rocket is made up of this first stage structure that contains a fuel tank for liquid oxygen (takes up about 2/3 of the length) and a fuel tank for RP-1, a modified form of kerosene. There are also helium tanks built into the fuel tanks that are used to force the oxygen and kerosene out of their tanks and into the engine as quickly as possible. This major section is designed and built by Yuzhnoye Design Bureau in the Ukraine, based in large part on the Russian Zenit rocket.

Interstage Assembly - This is the section that connects the first stage to the second and helps keep the rocket on the right course as it gets close to orbit by operating thrusters, small rockets used to control direction, as the rocket cruises between stages. Built largely from US-based Orbital Sciences' flight computers used on the Pegasus air-launched rocket, this hardware is considered exceptionally reliable which is great because if the rocket can't stay on course then there's no point in launching at all.

CASTOR® 30B Second Stage Motor - Unlike the first stage motors, the second stage is a solid-fueled motor built by Alliant Techsystems (ATK), a manufacturer from Utah that also built the Solid Rocket Boosters for the Space Shuttle. At a recent tour of NASA's Wallops Flight Facility a representative of ATK stated that the fuel formula they're using for Antares is a drastically better than the shuttle fuel which was designed in the 1970s.

Cygnus - The only part of the entire launch that will make it to orbit is this capsule-type spacecraft. It's made of two sections, the Pressurized Cargo Module (PCM) and the Service Module (SM). The SM is the "brains" of the vehicle, containing the solar panels, the rocket engine and thrusters, communications systems, and the environmental controls for inside the PCM, which is where the supplies and hardware meant for the station are stowed away. The SM is based largely on satellite hardware developed and built by Orbital Sciences in the United States. The PCM, on the other hand, was developed and built by Thales Alenia of Turin, Italy, sharing its design heritage with many sections of the space station and the Automated Transfer Vehicle (ATV) built by the European Space Agency.

 All those pieces from all those countries come together at the Horizontal Integration Facility at NASA's Wallops Flight Facility where they become the Antares rocket, one of America's newest launch options that is making low-Earth-orbit resupply an economic and routine process.

I hope you enjoyed this explanation of the Antares rocket and if you have any questions, comments, or suggestions then go ahead and leave a comment below! As always, thanks for reading!