Preliminary Plans For A Close Encounter With 253 Mathilde

NASA's Near Earth Asteroid Rendezvous (NEAR) mission is planning a close flyby of the asteroid 253 Mathilde in June 1997. The asteroid 253 Mathilde appears to be a distinct and interesting body worthy of further investigation. Unlike the S-class asteroids Gaspra and Ida explored in recent years by Galileo spacecraft flybys, Mathilde is a C-class spectral object and it has a larger diameter of about 61 km. Furthermore, Mathilde appears to have a very slow rotation period, possibly 17 days or longer. The plan is to navigate the NEAR spacecraft to within 1200 km of the center of Mathilde using a combination of NASA's Deep Space Network radio metric tracking and on-board optical imaging. The planned sequence of spacecraft activities will result in high resolution, multi-spectral images of Mathilde made throughout the approach ard departure. In addition, the navigation tracking will be used to estimate Mathilde's mass. The mass estimate should be accurate to about ten percent.