Dimensions: 16.5 x 10.5 cm and 10.4 x 9.9 cm
Description:
Two sections from a strip of live data from the Moon transmitted back to Earth by the Apollo Lunar Surface Experiments Package (ALSEP).
CHANNELS 1, 2, & 3 - Suprathermal lon Detector Experiment (SIDE]
SIDE analyzes the "ions" found near the Moon's surface. Ions, which are fragments of atoms that have been broken apart by ultra-violet light energy and collisions with other ions, make up nearly all of the Moon's tenuous "atmosphere." Not being "whole" atoms, ions are very unstable, acting like pieces of electricity that can reach speeds ranging from 25 to 250 miles per second! Most lunar ions come all the way from the Sun (in the "solar wind" of ions), while some originate from gases that have escaped from beneath the Moon's surface.
lons are distinguished from one another by their 1) MASS (or weight), 2) VELOCITY (speed at which they travel), 3) ENERGY (work done in accelerating the ions), and 4) CHARGE (number of missing electrons). SIDE performs its operation by counting ions of various energies and masses. Each of the three SIDE experiments on the Moon return eight channels of data. The three channels displayed on your sample include:
Channel I - Energy Step Sequencer
Displays SIDE's repeating 20-step "search pattern." Each of the experiment's 20 voltage settings allows it to check a different energy level at which ions are found.
Channels 2 & 3 - Total Ion Detector (TID)
Counts the total number of ions detected at each of the 20 "energy" settings of Channel 1. As the type of ion detected changes with each "voltage step" of Channel 1, the TID counts the number of ions at each new setting. Channel 2 counts the ions by thousands, and anything left over under 1,000 is shown on Channel 3. Consequently, Channel 2 lists the TID's "Most Significant Data" and Channel 3 indicates "Least Significant Data."
Counts the total number of ions detected at each of the 20 "energy" settings of Channel 1. As the type of ion detected changes with each "voltage step" of Channel 1, the TID counts the number of ions at each new setting. Channel 2 counts the ions by thousands, and anything left over under 1,000 is shown on Channel 3. Consequently, Channel 2 lists the TID's "Most Significant Data" and Channel 3 indicates "Least Significant Data."
CHANNELS 4, 5, & 6 - Passive Seismic Experiment (PSE)
PSE registers seismic vibrations of the Moon's surface caused by "moonquakes" and meteoroid impacts. The Moon does not experience quakes the size of those on Earth. In fact, the Moon is so "quiet" that the PSE was designed to be one million times more sensitive than instruments used to detect earthquakes. Even the footsteps of astronauts could be measured during their moonwalks.
Channels 4, 5, & 6 display PSE data in a three dimensional (x, y, z axis) pattern:
Channel 4-Shows seismic vibrations in the north-south direction (x axis). Channel 5. Shows seismic vibrations in the east-west direction (y axis).
Channel 6 - Shows seismic vibrations in the vertical (up-down) direction (z axis).
Channel 6 - Shows seismic vibrations in the vertical (up-down) direction (z axis).
A seismic event (quake or impact) causes vibrations that can last for hours, and is shown on a strip chart by a bulge in the thickness of the ink track. On one occasion, as the result of a huge meteoroid impact near the experiment, the bulge covered an entire channel. The ink track will remain straight during an authentic seismic event. If your sample shows a "wavy" PSE track, it is not indicating a seismic event, but rather an effect of a temperature change or a "leveling calibration" command sent by radio frequency from the ALSEP Control Network on Earth.
These sheets were given to visitors and prominent people of the Manned Spacecraft Center (MSC), called Johnson Space Center (JSC) since 1973.
