Meet Northrop Grumman's Cygnus spacecraft -- an uncrewed resupply vehicle for the International Space Station.

Developed under NASA's Commercial Orbital Transportation System program, it first flew on September 18th, 2013, in its Standard configuration, a smaller spacecraft than the Enhanced Cygnus that's currently flying.

The Enhanced Cygnus, sporting larger volume, greater cargo delivery capability, and larger solar arrays, first launched on December 6th, 2015 on an Atlas V rocket from Florida.

Cygnus designed to be taken to space by multiple rockets. Presently, it has launched on all four variants of Northrop Grumman's Antares rocket (110, 120, 130, and 230) and on United Launch Alliance's Atlas V rocket.

Cygnus has launched from both Virginia and Florida, making it the only International Space Station vehicle to have launched from more than one spaceport on Earth.

Cygnus was originally developed by Orbital Sciences, which then merged with ATK to become Orbital ATK. Orbital ATK was then bought by Northrop Grumman, making Cygnus a Northrop Grumman property.

The Antares rocket was designed to serve NASA's cargo launch market need for a resupply vehicle to the International Space Station.

Originally named Taurus II, it is an expendable rocket developed and built by Orbital Sciences and is now owned and operated by Northrop Grumman.

It has only launched Cygnus crafts to the Station but is available on the wider commercial market.

Somewhat unique in the rocket world, it uses a liquid fueled first stage and a solid propellant second stage. Most rockets use liquid fueled second stages as it is far easier to get a perfect initial orbit with liquid propellant engines than with solid propellant rockets.

Antares has four variants, the current being the Antares 230+ which flew for the first time on October 17th, 2016.

Antares 230+:

Height: 42.5 m / 139 ft
Diameter: 3.9 m / 13 ft
Mass: 289,000 kg / 657,000 lb
Payload to LEO: 8,000 kg / 18,000 lb

First stage:
Engine: 2 x RD-181
Thrust: 3,844 kN / 864,000 lbf (total)
Fuel: Liquid Oxygen / RP-1 kerosene
Burn time: 215 seconds

Second stage - Castor 30XL:
Engine: Solid Rocket Motor
Thrust: 474 kN / 107,000 lbf
Propellant: Hydroxyl-terminated polybutadiene / aluminium
Burn time: 156 seconds

Image: NASA

The Mid Atlantic Regional Spaceport (MARS) is a commercial space launch facility located at the southern tip of NASA's Wallops Flight Facility on Wallops Island, Virginia.

MARS began in July 2003 as a joint venture between Virginia and Maryland.

The first rocket launch from MARS occurred on December 16th, 2006 and was an Orbital Sciences Minotaur I rocket with the TacSat-2/GeneSat-1 payload.

To date, MARS has hosted the four Antares rocket variants, the Minotaur I, Minotaur V, and ALV X-1 rockets.

The Minotaurs and Antares were at first Orbital Sciences rockets and ALV X-1 was an ATK rocket. With the merger of Orbital Science and ATK into Orbital ATK, and Orbital ATK's subsequent purchase by Northrop Grumman, Northrop Grumman now technically owns all of the rockets (or at least their designs) that have ever flown from MARS.

After launch, Cygnus will spend a few days boosting itself up to the International Space Station. When it arrives, two crew members will grab it with the Station's robotic arm, Canadarm2, and berth it to the Earth-facing, or Nadir, port on the Unity module.

Unity, also called Node-1, was the second module of the ISS to be launched. Taken to orbit on the STS-88 mission of Shuttle Endeavour, Unity was joined to the Russian Zarya ("dawn") module on December 6th, 1998.

The Unity nadir port hosted two Space Shuttle dockings on the STS-97 and STS-98 missions of the Shuttles Endeavour and Atlantis in December 2000 and February 2001.

Since December 2015, it has been the only berthing port used for the Cygnus cargo spacecraft.

Picture: The Unity module (no solar panels), with its nadir port visible in its center, is joined via spacewalk (astronaut visible to right of where Unity and Zarya connect) to the Zarya module during STS-88 in December 1998. Credit: NASA