Session
Technical Session I: New Applications & Sensor Technology
Abstract
A subset of the presently-defined NASA robotic lunar exploration objectives may be achievable with a new mission architecture involving the Pegasus winged rocket, small satellites, and a new class of Earth-Moon trajectories incorporating ballistic lunar capture. Enabling this potentially low-cost method of lunar exploration - perhaps for a few tens of millions of dollars per mission - is the application of the Weak Stability Boundary Theory developed by Belbruno during 1987-89, which leads to ballistic ("maneuverless") Earth-Moon trajectories. On such a path, a spacecraft could be orbited at the Moon for little additional ∆ V (< 50 m/s for minor trajectory correction maneuvers) beyond that supplied by the Pegasus for the initial Earth departure burn, resulting in a significant propellant savings. (Additional maneuvers would then be required to establish a more useful lunar orbit.) The price for this savings is an extended trip time to the Moon of 3-5 months. This type of trajectory is presently being demonstrated for the first time by the Japanese Hiten spacecraft, using an application developed in 1990 by Belbruno and James K. Miller at JPL; it may also be employed for the Japanese Lunar-A penetrator mission in 1996.
If conventional Hohmann-like Earth-Moon transfers are employed, present versions of the Pegasus - even if outfitted with a small fourth stage can deliver only modest-sized spacecraft to the Moon (< 50 kg), most likely not big enough to address presently-defined NASA robotic lunar exploration objectives. In contrast, if the ballistic capture technique is employed in conjunction with four-stage. versions of Pegasus, an additional 15 to 30 kg or more of spacecraft mass is gained, resulting in 65-80 kg small satellites which may be able to accomplish some meaningful objectives at the Moon, including gravity field determination, magnetospheric studies, and other related fields, particles and waves objectives. Advertised growth versions of the Pegasus combined with recent developments in small-satellite technology may allow for more capable satellites to reach the Moon, perhaps enabling the achievement of more demanding objectives. In the current tight budgetary climate, this new mission architecture may allow for incremental achievement of some NASA lunar science objectives by enabling significant enhancements in delivered small lunar satellite mass and capability while at the same time reducing the total mission costs for simple lunar missions. This lower-cost way of reaching the Moon may also provide an avenue for pursuing attractive commercial lunar activities and interesting lunar-based small-satellite constellation concepts.
To the Moon from a B-52: Robotic Lunar Exploration using the Pegasus Winged Rocket and Ballistic Lunar Capture
A subset of the presently-defined NASA robotic lunar exploration objectives may be achievable with a new mission architecture involving the Pegasus winged rocket, small satellites, and a new class of Earth-Moon trajectories incorporating ballistic lunar capture. Enabling this potentially low-cost method of lunar exploration - perhaps for a few tens of millions of dollars per mission - is the application of the Weak Stability Boundary Theory developed by Belbruno during 1987-89, which leads to ballistic ("maneuverless") Earth-Moon trajectories. On such a path, a spacecraft could be orbited at the Moon for little additional ∆ V (< 50 m/s for minor trajectory correction maneuvers) beyond that supplied by the Pegasus for the initial Earth departure burn, resulting in a significant propellant savings. (Additional maneuvers would then be required to establish a more useful lunar orbit.) The price for this savings is an extended trip time to the Moon of 3-5 months. This type of trajectory is presently being demonstrated for the first time by the Japanese Hiten spacecraft, using an application developed in 1990 by Belbruno and James K. Miller at JPL; it may also be employed for the Japanese Lunar-A penetrator mission in 1996.
If conventional Hohmann-like Earth-Moon transfers are employed, present versions of the Pegasus - even if outfitted with a small fourth stage can deliver only modest-sized spacecraft to the Moon (< 50 kg), most likely not big enough to address presently-defined NASA robotic lunar exploration objectives. In contrast, if the ballistic capture technique is employed in conjunction with four-stage. versions of Pegasus, an additional 15 to 30 kg or more of spacecraft mass is gained, resulting in 65-80 kg small satellites which may be able to accomplish some meaningful objectives at the Moon, including gravity field determination, magnetospheric studies, and other related fields, particles and waves objectives. Advertised growth versions of the Pegasus combined with recent developments in small-satellite technology may allow for more capable satellites to reach the Moon, perhaps enabling the achievement of more demanding objectives. In the current tight budgetary climate, this new mission architecture may allow for incremental achievement of some NASA lunar science objectives by enabling significant enhancements in delivered small lunar satellite mass and capability while at the same time reducing the total mission costs for simple lunar missions. This lower-cost way of reaching the Moon may also provide an avenue for pursuing attractive commercial lunar activities and interesting lunar-based small-satellite constellation concepts.
