USAF 12-Meter Orion Bomber Diagram

The design, as Scott Lowther explains, was described only in limited detail, as a Strategic Weapons System. This concept seen as a fulfillment of an expected Strategic Air Command strike capability for the post-1975 period. 

The spacecraft would be launched fully loaded, weapons systems and crew aboard. It was to be lofted by a cluster of seven 156-inch diameter solid rocket boosters. Burn time would be slightly more than two minutes. The rockets would boost the Orion to an altitude of 250,000 feet and a speed of 10,000 feet/second. After staging, and still within the uppermost reaches of Earth's atmosphere, the nuclear pulse engine would fire, ejecting one sub-kiloton nuclear pulse unit per second, powering the Orion the rest of the way to orbit. 

After systems check-out in low Earth Orbit the nuclear pulse engine would be used again to boost the vehicle to a 100,000 n.m. apogee Hohmann transfer orbit, and boost again at 100,000 n.m. to circularize the orbit. One more boost would place the ship on an orbit with a 100,000 n.m. perigee and with an apogee beyond lunar orbit. Once there a maneuver deltaV of 75,000 feet/second would be available.  

The vehicle would have a vacuum thrust of 970,000 pounds, a specific impulse of 3,670 seconds and a gross weight of 1, 750,000 pounds. The total liftoff weight including the solid rocket boosters was 15, 000,000 pounds. Payload delivered to the 100,000 n.m. perigee elliptical orbit was to be 300,000 pounds. 

The spacecraft would remain on orbit for its operational lifespan, expected to be 15 to 20 years. Crew complement was to be 20 or more -- the exact number to be determined. Flight operations would be 24/7. Crews would be shuttled up for six month tours of duty. Given the technology advancements to be expected over a 20+ year operational lifespan the Orion was to be designed for easy replacement of the payload modules as well as replacement of the crew consoles and instruments. 

Planned weapons capability was not defined in any detail. The offensive weapons were to be carried internally, and fully accessible by the crew to permit maintenance. Unspecified defensive capabilities were to be carried. The offensive weapons (surely to be megaton-range nukes and/or vast numbers of smaller nuclear weapons) could be launched one of two ways:

1. Using rocket motors, the weapons would be launched from deep space. they could be guided to their targets.

2. The weapons could be released from the Orion near Earth. The Orion would use its considerable propulsive capabilities to boost itself from deep orbit to a close hyperbolic flyby of the Earth.

US Space Force

On the advantage of a space based nuclear force. 

Such a force would be considerably more difficult and expensive to attack than even ballistic missile submarines. Nuclear pulse propulsion is the best choice for such a force. Orion is uniquely capable of providing on-orbit maneuvers useful to military missions. While chemical rocket systems would struggle to conduct high angle plane changes, altitude changes, or phase changes, Orion could not only do them but do them rapidly. The extremely high delta-V capability of an Orion means that Hohmann transfers, the most fuel efficient means of changing orbits, could be dispensed with in favor of more direct boosts. The military value of this is clear -- an Orion could not only chase something down - another spacecraft, a missile or warhead, or even a ground target -- it could also evade interception.

While the physics and engineering of the Orion propulsion system were being worked out at General Atomic a group of officers at the Air Force Special Weapons Center (AFSWC) at Kirtland AFB, New Mexico were tasked with defining military applications for Orion. 

These plans evolved over time and a number of deployment plans were examined, these included ground based deployment to hardened silos, space based deployment as described, or mixed deployment options. Initial proposals, circa 1962, included the 40-meter 4,000 ton Orion Battleship. 

According to the 1962 USAF Space Plan in-space deployment of the force would be as follows: 

Low altitude (LEO) Force - Reconnaissance and Ballistic Missile Defense. 

Mid altitude (GEO) Force - Space Fleet Defense.

Deep Space Force (Lunar orbit and beyond) Survivable Deterrence, Fleet Command and Control.

Plans called for as many as 50 nuclear pulse spacecraft stationed on orbit. Fleet support would require an extensive ground based and on-orbit infrastructure for servicing and maintenance of the nuclear pulse spacecraft. One can foresee a conventional ground launch and return capability requirement for resupply and personnel rotation. LEO and GEO staging and logistical bases and on-orbit logistical vehicles.