LUNAR LAND
image by Don Higdon and Susan Hoban
The Lunar Reconnaissance Orbiter, scheduled to launch in October 2008, will carry the Lunar Orbiter Laser Altimeter (LOLA). LOLA will produce topographic maps of the Moon using a LIDAR ranging system. We have developed a hands-on activity for middle and high school students that uses an ultra-sound motion detector to simulate LOLA LIDAR mapping. This activity is presented in the context of a larger module, which involves a simulated lunar search-and-discovery mission, using simple robots equipped with various sensors. The students use the topographic map that they produce to determine the path that their robot will traverse through Lunar Land, a 150 cm-square mock-up (above left) of a surface with obstacles (craters!?) of various heights. The figure above shows, in the center, Lunar Land, and on the right is the topographic map of Lunar Land generated using the ultrasound motion detector. This lesson offers an opportunity to engage students in an activity analogous to that which real lunar scientists might do, and provides an opportunity for a discussion of lunar science, fundamentals of measurement (including measurement uncertainty), spatial resolution in the context of remote sensing, and graphical representation and analysis of data, for starters. This effort is supported through the NASA Exploration Systems Mission Directorate Education.
Don Higdon and Susan Hoban
Technical Details
Here are detailed instructions for this activity.
LPOD earns a commision when you buy ANY book from Amazon thru LPOD! Have you bought a book lately?
This sounds like an interesting experiment for the students; but I must admit I am baffled by the presentation of the results.
I understand from the detailed instructions that the horizontal axis of the topo map is the sample number in a series of runs stacked vertically. But I am unable to reconcile the “East” and “North” labels with any convention for specifying directions on the Moon. Does the label mean the left side of the map more “East” than the right? Or that Run 28 (at the top) more “East” than Run 1 (at the bottom)? And is there any way to reconcile the chart with the convention used by real lunar cartographers that if North is up, then East increases to the right?
Also the vertical unit (meters from detector??) seems to be unspecified, and the color scheme (with blues and reds seemingly intermixed at random) is highly non-intuitive, and extremely difficult to interpret (e.g., is there any data in the top two categories?). Evidently (from the instructions), the data obtained is actually the apparent velocity of approach or recession of the test surface as a motion detector at a fixed distance is scanned horizontally across it. Turning this into height data requires integrating the velocity over time, and I was unable to find any directions for how the students are expected to do this (are they in a non-included Excel spreadsheet?); or if they are asked to perform any “pre-flight” calibration to ensure that they are obtaining accurate results in terms of true millimeters of surface relief. Also, are real LIDAR data actually derived from an integration procedure like this?
Hopefully by the time the students become practicing scientists they will have learned to present their results in a clearer fashion.
– Jim
Comment by JimMosher — November 11, 2007 @ 11:54 am
Actually, it’s a very clever introduction to this complex subject!
The 150 cm mat on the floor is the intremediate blue, here is where the robots will transverse over.
The Purple represents steep topography, the other colors Height. Further, North is in Front of the Instructor,
South is behind, East is to his Left, West is to his Right. The Device moves from 1 to 29 in increments of 1 cm leftward, then the rail [Orbit]is pulled southwardly 1 cm; which recycle the whole procedure again. Some of the circles[craters] have central peaks in them! Nice touch!
Jim, I think because of your vast experience and extensive knowledge base, this demo is like a thin soup misssing salt and texture, But if you can steer yourself in the shoes of a complete novice, then this is an appropiate step leading into the right direction. I just wish I knew how to convert an ultra sonic devices into 2D visual imager, cuz that too is really way cool!
Comment by Abadin — November 11, 2007 @ 10:47 pm