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The Hangar / Antares


An Antares on the launch pad at the Mid-Atlantic Regional Spaceport. Photo Credit: Jason Rhian / SpaceFlight Insider

Antares 200
Antares 230
Class Medium-Lift Launch Vehicle
Country of Origin US Flag United States
Manufacturer Orbital ATK Logo
Height 41.9 m
Diameter (Core) 3.9 m
Diameter (Fairing) 3.9 m
Mass 298,000 kg
Stages 2-3
First Stage
Manufacturer Yuzhnoye
Engine NPO Energomash RD-181
Fuel RP-1/LOx
No. Engines 2
Length 27.6 m
Diameter 3.9 m
Empty Mass 20,600 kg
Propellant Mass 242,000 kg
Thrust (Sea level) 1,922 kN
Thrust (Vacuum) 2,085 kN
Burn Time 215 sec.
Second Stage
Engine Castor 30XL
Manufacturer Orbital ATK
Fuel QDL-1, HTPB, Al
Length 5.99 m
Diameter 2.34 m
Empty Mass 2,100 kg
Propellant Mass 24,200 kg
Thrust 533.3 kN
Burn Time 155 sec.


Antares is a medium-lift expendable launch vehicle developed by Orbital Sciences (now Orbital ATK). Antares primary mission is to support cargo Cygnus spacecraft flights to the International Space Station (ISS) under the agency’s Commercial Orbital Transportation Services (COTS) and Commercial Resupply Services (CRS) contracts. The vehicle currently is launched out of the Mid-Atlantic Regional Spaceport’s (MARS) Pad-0A located at NASA’s Wallops Flight Facility in Virginia.

Originally named the Taurus II, Antares has the capability of sending payloads weighing more than 11,000 lbs (5,000 kilograms) to low-Earth orbit (LEO).

Antares conducted its inaugural test flight on April 21, 2013, using the 110 configuration of the launch vehicle. That flight, designated Antares A-ONE, launched a Cygnus Mass Simulator to an orbit of approximately 150 by 160 miles (240 kilometers by 260 kilometers) with an inclination of 51.6 degrees. Four cubesats were deployed from the mass simulator for Spaceflight Inc. 

The second Antares launch was a demonstration flight under NASA’s COTS program, designated Orb-D1 and was the first time that Orbital Sciences had named one of the cargo vessels in honor of an astronaut – G. David Low. Low had worked with Orbital and he passed away from colon cancer in 2008. An Antares, in its 110 configuration, was used to propel the S.S. G. David low and its  1,543 lbs (700 kilograms) worth of cargo toward the ISS.

The first operational mission under the $1.9 billion CRS contract that Orbital had entered into with NASA took place on January 9, 2014 with the flight of the S.S. C. Gordon Fullerton. Fullerton had gone on to become an executive with Orbital Sciences before his passing on August 21, 2013. The flight utilized an upgraded Antares 120 rocket with an Alliant Techsystems (ATK) Castor 30B upper stage. 

On January 13, 2014, Orbital Sciences carried out the second operational flight of the Antares rocket under the Orb-2 mission. The Orb-2 Antares rocket successfully delivered the Cygnus spacecraft and its 3,668 lbs (1,664 kilograms) worth of cargo, crew supplies and experiments to the International Space Station.

2014 In-Flight Anomaly

The Orb-3 mission launched on October 28, 2014 (CRS Orb-3) ended in an explosion that resulted in the loss of the rocket, the S.S. Deke Slayton Cygnus spacecraft and its cargo. The failure stemmed from a failed turbopump on one of the two Aerojet Rocketdyne-provided AJ26 engines used in Antares’ first stage. These engines were built in the 1960s, for use on the Soviet Union’s massive N-1 Moon rocket. Known as the NK-33, these engines were purchased by Aerojet Rocketdyne and renamed the AJ-26. Aerojet Rocketdyne made some modifications, including the removal of wiring, the addition of some electronics, modifying the NK-33 to use U.S. fuels and changes to the engines’ steering system. The AJ-26 encountered two failures on the test stand at NASA’s Stennis Space Center prior to the Orb-3 accident. On December 17, 2014, Orbital announced it would use the NPO Energomash RD-181 on the second-generation Antares rockets and had signed an agreement for up to 60 RD-181 engines. in late 2015, it was announced Aerojet Rocketdyne would pay Orbital ATK (the company had merged with ATK by that time) $50 million and buy back 10 AJ26s. 


On October 17, 2016, the new Antares 230 rocket with two RD-181 rocket engines in its first stage, returned the Antares family of launch vehicles to service. These engines are described as providing approximately 440 kilonewtons (100,000 lbf) more thrust than the dual AJ26 engines used on the Antares 100. The Cygnus that was launched atop this rocket, the S.S. Alan Poindexter, carried 10,740 lbs (4,870 kilograms) of cargo to the ISS.

Mission Profile

To date, Antares has launched exclusively to the ISS from Wallops Flight Facility. Orbital ATK advertises that the vehicle is compatible with facilities at Vandenberg Air Force Base in California, Cape Canaveral Air Force Station in Florida, and Kodiak Launch Complex in Alaska.

Upon liftoff, the twin RD-181 engines provide thrust vector control to perform pitch and yaw maneuvers. The first stage burns for 215 seconds before main engine cutoff and stage jettison. Following first stage jettison, there is a pause of approximately one minute, after which the interstage surrounding the upper stage motor nozzle separates and the second stage motor ignites. The payload fairing jettisons after second stage ignition. The second stage burns for 156 seconds before burning out, after which the payload separates and coasts to the International Space Station.

Configurations and Performance

First Stage Second Stage Third Stage
1 – Two AJ26 engines
2 – CASTOR 30B 0 – None
2 – Two RD-181 engines 3 – CASTOR 30XL 1 – Bi-Propellant
Third Stage
    3 – Star 48-based
third stage

Antares has a number of configurations designated by the propulsion systems that it utilizes. Whereas the 100 series flew using the Aerojet Rocketdyne AJ26 engine in its first stage, the 200 series uses the RD-181. These engines utilize a mixture of RP-1 (a highly-refined form of kerosene) and liquid oxygen (LOX). 

Meanwhile Antares’ second stage uses either Orbital ATK’s Castor 30B or Castor 30XL solid rocket motors. While Antares flies without a third stage when launching Cygnus to the International Space Station. However, the Antares launch system does offer an optional third stage using either an Orbital ATK Bi-Propellant Third Stage or a Star 48-based third stage.

Antares Payload Upmass

  Variant Mass
LEO 230 7,000 kg
SSO 231 3,000 kg
GEO 232 2,700 kg

The 230 variant of the rocket is rated to launch up to 15,400 lbs (7,000 kilograms) to LEO or up to 7,700 lbs (3,500 kilograms) aboard Cygnus to the ISS. The 231 variant is designed to launch up to 6,614 lbs (3,000 kilograms) to Sun-synchronous orbit (SSO). The 232 variant will launch up to 5,600 lbs (2,700 kg) to geosynchronous equatorial orbit (GEO).

The Antares first stage is designed and built by the Ukrainian company Yuzhnoye and is based on the Zenit rocket, with overall vehicle integration being performed by Orbital ATK. The stage produces 3,265 kN of thrust, burning for 215 seconds. The Castor 30XL second stage SRM produces 293.4 kN of thrust and burns for 156 seconds.


To date, Antares has flown only payloads pertaining to the Commercial Resupply Services contract. However, Orbital ATK’s literature on the vehicle includes payload data for a wide array of orbits and therefore Antares can be used to send an array of payloads for various customers.

Antares 200

Exploded view of an Antares 200 with the Cygnus spacecraft.

Launch History
Status Operational
Launch sites Mid-Atlantic Regional Spaceport Pad 0A
Total Flights 6*
Successes 5*
Partial Failures 0*
Failures 1*
First Flight Antares A-ONE
April 21, 2013
Notable payloads CRS Orb-3

* Data current as of February 2017

Recent News

More Antares News…

Upcoming Launches

NETOct 1 OA-8
Vehicle Antares 200
Location Mid-Atlantic Regional Spaceport LP-0A
Time TBD
NETNov 17 OA-9
Vehicle Antares 200
Location Mid-Atlantic Regional Spaceport LP-0A
Time TBD

Photo Gallery

Antares graphics and photos provided by SpaceFlight Insider.