The Advent spacecraft launches vertically from water and lands horizontally like a seaplane. It is a winged rocket designed to glide down to the ocean surface for a safe, controlled landing. It is safer than an airliner because it is mechanically much simpler, having fewer components, a shorter run time and very robust mechanical parts. In fact, the Advent vehicle requires only seven simple “on” or “off” signals to fully control the propulsion system. The guidance system uses redundant control surfaces on the trailing edges of the wing for propulsion efficiency, steering, atmospheric re-entry and aerodynamic control for gliding and landing.
Unlike conventional launchers, the Advent design relies on low cost propellant, cost-efficient re-entry thermal protection and SIMPLE ocean-based operations, significantly reducing the cost per pound for payload delivery. Ocean operations offer distinct advantages over land-based facilities, including greater safety due to the increased potential landing area, the flexibility of having the launch site relatively close to the payload source, and the ability to purchase both propellant and facilities at world market prices. The system is minimally constrained by local regulations, potential taxes and insurance that are typically imposed on land-based systems.
Probably the most important feature of the Advent concept is the similarity of the two stages. This is expected to significantly reduce the development cost and schedule. The development plan is to build and test the first relatively small vehicle that will eventually be used as the orbiter stage. Then another very similar vehicle will be built that is about twice the size. It will be tested much like the orbiter stage. The two will then be connected and flown for the first orbital delivery. The construction of the third vehicle will again be much like the first two. When the third vehicle is complete, the booster from the first orbiter, the second vehicle, will be used as an orbiter and the second orbit delivery system will be complete. Each new vehicle will be about twice the size of the previous vehicle and will provide the capability of increasing the payload by a factor of ten. The first system is planned for 1000-pound deliveries, the second for 10,000 pounds and the third for 100,000 pounds. The fourth delivery, with construction of the fifth vehicle is planned to deliver a million pounds to Earth orbit. All this can be accomplished with the engineering design and operational experience developed with the initial small vehicle which will be about 5 feet in diameter and 25 feet long.
The Advent concept requires no new technology or fabrication skills but does offer an exciting alternative to today’s high-cost Earth orbit delivery.