Slashdot Mirror

← Back to Stories (view on slashdot.org)

NASA Shakes, Bakes, and Rattles Lunar Spaceship

Posted by ScuttleMonkey on from the shake-rattle-and-roll dept.

coondoggie writes to tell us that NASA has apparently successfully concluded putting the new Lunar Reconnaissance Orbiter through its paces. Using vibration and rotation tests NASA scientists were able to determine the center of gravity and were also able to observe the structural integrity during the vibration tests used to simulate launch aboard an Atlas rocket. "It is expected that the LRO will by the end of the year make its way to NASA's Kennedy Space Center in Florida for final launch preparations. The orbiter and the Lunar Crater Observation and Sensing Satellite, a mission to smack into the moon in search of water ice, are scheduled to launch atop an Atlas V rocket from Cape Canaveral Air Force Station in Florida sometime between Feb. 27, 2009 and the end of March 2009."

2 of 44 comments (clear)

  1. Yes, but by rarel · · Score: 5, Funny

    Will it blend?

  2. Re:The center of gravity is important. by Anonymous Coward · · Score: 5, Informative

    I happen to be an aerospace engineer (formerly at JPL), and the center of gravity is actually extremely important after launch as well. NASA is not pulling your leg.

    You may replace the "center of gravity" with "mass distribution" or "center of mass" if it makes you feel better. The term is a hold-over from the early days, and is a term of art than any engineer would recognize and understand. You just need the contextual information that an engineering education provides.

    The actual product of the test is both a location of the center of mass of the spacecraft and a mass distribution matrix, commonly called an inertia matrix or inertia tensor.

    The attitude control system (my specialty) requires very accurate knowledge of where the center of gravity and the geometric centers are. These are used to compute both control and disturbance torques on the spacecraft. Without a C.G test it is almost impossible to get the pointing performance (sub-arc-second) many of the payloads require on modern spacecraft. The CAD/Solidworks models are rarely good enough for this, and although some things can be done to estimate the C.G. in-orbit, you still have to get through launch and initial checkout with whatever data you launched with. C.Gs are estimated in space to handle things like fuel loss.