The crew vehicle is another variant of the "2+1" configuration. It can transport up to 4 astronauts to and from the Earth station. As usual, the number of flights and / or copies can be adjusted to the station occupancy and duty time. Thus, cost and safety can be the principle considerations in the vehicle design.
The astronauts are in a pressurized compartment, which is the cockpit of a reentry glider. Space suits may be unnecessary, although this is more an issue in station design, namely, the compartment must form a pressure seal with an entryway to avoid them. The glider is a third component of the launch vehicle; the second stage reenters and is recovered separately, in the ocean as for any other "2+1" vehicle.
Assuming the glider weight to be 10 tons, a standard multiplicity 2 variant of the "2+1" booster could be used. If the glider weight is less, a special smaller booster would be required. Smaller engines might have other uses as well. It would seem that the glider and second stage could be either "horizontally" or "vertically" stacked.
A simple design for the reentry vehicle provides a "box" for four astronauts. Dimensions for this might be 5 feet high by 7 feet wide by 11 feet long. The rear two "seats" can be removed, and used for a small cargo, or a gurney for medical emergencies. Access is through a hatch rearward on the top; the vehicle docks upside-down, with the hatch attaching to an access chamber, which is at one end of the "vertical" cylinder of the inner station assembly. Cameras are used instead of a window ; 3D methods might be investigated.
For landing on a runway the box can sit atop a glider. The runway could be at Vandenburg AFB, so that an aborted approach would result in landing in the ocean, or at worst in a safety zone on land. A probability of fatality of one in 500 flights might be achievable. There are two choices; the box is crashproofed against glider failure, or can separate from the glider. The box has a two layer entry surface, with the outer being reusable and the inner ablative (and strengthened, e.g., carbon fiber composite); on the bottom the glider could function as the layer. The glider is inexpensive, consisting of fuselage structure with reusable heat shield, landing gear, and control rockets. The box has rockets for control in failure modes, parachutes, etc. In the case of a separating box the glider can have a secondary flight control computer, so that even it might be recovered (in the ocean) in the event of erroneous separation (there was a comment at the 2003 Mars Society convention that this was a concern in OSP design). For abort early in flight, even before launch, a separating box seems preferable; the box can have rockets and parachutes allowing for this.
At one point, the Orbital Space Plane had a medical transport requirement. Many years of experience with manned space flight have shown that medical emergencies are rare, much rarer than the accepted crew loss rate for the Plane. However as noted the capability could be provided at modest additional cost in the box, by having an area where a gurney could be stowed; and some medical equipment. A requirement for online medical crew monitoring seems frivolous. A standby vehicle could be kept at the station, with equipment to rapidly move it into place from the standby position