In comparison to the Space Shuttle, Hermes is a substantially smaller vehicle. As well as being scaled down, it does not share the ogival planform of the Shuttle, having opted for a highly-swept delta wing complete with wingtip devices, similar to the proposed Boeing X-20 Dyna-Soar spacecraft. Like the Shuttle, it would have had a pressurised cabin in which a maximum of six crewmembers could be seated, two of which serving as the pilots; while an unpressurised cargo bay positioned aft of them would have been fitted with large doors spanning the length of the bay along the fuselage. The vehicle would have been powered by a pair of 2,000N-thrust liquid propellant rocket motors, which were to have been identical to those used on the L4 low-energy upper stage of the Ariane 5.