The Orbital Vehicle (OV) is really nothing more than a standard space vehicle and propellant tanks and a rocket engine. The basic OV design has been around for half a century (Image 1).
 |
| Image 1: The OV internal view |
The top of the space truck will have the USIS Docking Ring to mechanically connect payload.
Between the LH2 and LO2 tanks is the Intelligence Module (IM). Electrical power will be provided by a fuel cell being fed cryogenics.
The IM also houses the four Reaction Control System (RCS) quads. The propellant for the quads will come from the main OV propellant tanks. The quads will burn 11 kg of propellant per day, which gives an 8–day operational duration (Table 1).
The OV will have the propellant tanks replenished for refurbishment and reuse whilst in space. The OV will also have the capability of purging the propellant tanks as well.
The Cargo Hold Guide Rails (CHGR) are used to secure the OV to the VentureStar Cargo Hold.
The exterior of the space truck (Image 2) will be painted white to help offset increased internal heating. The RCS will be located in each of the rounded corners.
 |
| Image 2: The OV external view |
Our spacecraft begins its life as a Core Orbital Unit (Table 2). This module is the basic building block upon which other components are attached.
The OV inert mass specifications are summarized in Table 3, and the OV propellant mass specifications are summarized in Table 4. Propellant boiloff is approximately 14 kg per day.
Stage Mass = Inert Mass + Propellant Mass
Stage Mass = 2276 + 18053
Stage Mass = 20,329 kg
Mass Ratio = Propellant Mass / Stage Mass
Mass Ratio = 18053 / 20329
Mass Ratio = 0.888
The OV will be inserted into RV cargo bay in the same manner as the all other cargo, except one other item will be added. The OV will need to be filled with propellant, and the best way to do that is while sitting on the launch pad. We will therefore add two Propellant Output Docking Collars into the cargo bay (Image 1) so that two vehicles can be filled at the same time. The propellant hardware should have a mass of no more than a few hundred kilograms.
 |
| Image 1: Internal view of cargo bag looking forward from aft |
Once the vehicles are loaded, the Propellant Input Docking Collar attaches to the RV Propellant Output Docking Collar (Image 2).
 |
| Image 2: OV loaded into RV cargo bag and attached to propellant output |
Once the RV is placed on the Launch Pad and begins to fill its propellant tanks, it will also fill up the OV propellant tanks.
::