missions to small bodies and the Moon


To the right is cover art from a Discovery proposal that I submitted to NASA in 2004. In 2010 I led a similar mission proposal, this time to an ice-rich body, using the same radar reflection imaging technology that was applied with great success to the Mars polar caps.  The mission goal, achievable with SHARAD-class radar technology, is to globally image a comet nucleus or ice-rich asteroid in 3D to a resolution of around 10 m, a sort of imaging tomography.



Moving on to more far-fetched (or crazily hatched) ideas, EGGS (Expendable Geology and Geophysics Stations) are bottom-weighted, self-righting, low-cost ellipsoidal sensors designed for ballistic delivery onto the surface of a low gravity planetary body such as an asteroid, comet, or small moon. Released from orbit by a rendezvous spacecraft, EGGS strike the surface at the escape velocity, which for a 1 km radius asteroid is about 1 m/s. After initial contact they tumble to a resting configuration, landing heavy-side down without the use of any moving parts or control system. This geometry and lop-sided mass distribution is under study in modeled asteroid environments for the purpose of low-cost, low-risk in situ exploration. EGGS contain an internal vibrator and accelerometer to conduct seismology, and terminate with an explosion event. While the details are top secret, a first concept design is shown at right.


In 2007 NASA held a competition to see who could best make use of the spare payload that became available when its Lunar Reconnaissance Orbiter (LRO) moved up into a larger launch vehicle. The result was an inexpensive spacecraft, NASA Ames’ Lunar Crater Observation and Sensing Satellite, which after LRO’s separation took command of the upper stage and guided the empty booster, shown at left, to impact a permanently shadowed region of the lunar poles. The goal was to confirm the presence or absence of water ice in these extremely cold (~40-50 k) soils to the 0.5% level, by observing the impact for ~4 minutes until the shepherding spacecraft itself strikes the Moon.  The mission, though on the cheap, was an outstanding success.  My role was in the impact modeling effort.


Weebles wobble but they don’t fall down.