 Suprathermal Ion Detector Experiment (right) with Cold Cathode Gauge Experiment (left) on Apollo 15 | |
| Acronym | SIDE |
|---|---|
| Notable experiments | Apollo 12, 14, and 15 |
| Manufacturer | Bendix Corporation |
The Suprathermal Ion Detector Experiment (SIDE) was a lunar science experiment, first deployed by astronauts on the lunar surface in 1969 as part of Apollo 12, and later flying on Apollo 14 and Apollo 15. [1] The goal of SIDE was to study any potential lunar ionosphere and the solar wind. [2]
The idea of landing a positive ion detector on the Moon was first proposed by the lunar science branch of NASA's Manned Space Science Program Office in 1964. If, as was assumed, the Moon did not have any kind of bow shock and limited atmosphere then "daytime" measurements would mostly correlate with the undisturbed solar wind. However, during the lunar night it was believed that due to the presence of either shock limbs or turbulent flow of the solar wind, measurements by a positive ion detector would not simply be of undisturbed solar wind. [2] While experiments for assessing non-ionised gases would be preferred for analysing the Moon's atmosphere, ion detectors and ion spectrometers were more mature technologies. [3]
It was feared that the Lunar Module could release enough gas from its engine exhaust to constitute 5% of the entire potential atmosphere of the Moon and contaminate any results from the experiment. [3]
SIDE consists of two positive ion detectors, a mass analyser and a total ion detector, located side by side in a parallel arrangement. The goal of the experiment was to provide mass per unit charge spectra of the positive ions present near the Moon's surface. [4] To mitigate any possible effects of the Moon's regolith having an electric potential that might impact detection of low energy ions, the instrument would sit on top of a wire screen that would apply a variety of charges to counter any potential surface voltage. [4]
The housing for SIDE also housed the electronics for the Cold Cathode Gauge Experiment (CCGE). [5] The SIDE command and control circuits also supported the CCGE. [6] The CCGE was separated from SIDE by a 1-metre-long (3.3 ft) cable. [6]
The experiment found evidence that the limb shock generated a large cloud of hot solar-wind electrons. SIDE also found atmospheric ions were accelerated by the solar wind and would be reimplanted at the terminator. Daytime observations of the lunar atmosphere was made difficult by highly variable solar-wind and extreme-ultraviolet flux. [7]
Whilst the lunar surface daytime electric potential was found to be +10 V, this became -100 V at sunset and sunrise, and -250 V at night. [7] All deployed instruments would regularly detect exhaust gases from the Lunar Module descent and ascent engines, including when the Apollo 14 lunar module ascent stage overflew the Apollo 12 landing site at an altitude of 28 kilometres (17 mi). [7] [8]
The SIDE instrument was key in identifying a new plasma regime in the lobes of the Earth's magnetotail, consisting mostly of low-energy plasma. This plasma consisted most of protons and ionized atomic oxygen and nitrogen, likely derived from the Earth's atmosphere. [7]
The Apollo 14 SIDE instrument provided the first signal that suggested the presence of water vapour on the Moon. [9] Artificial origins from the Apollo 14 lunar module could not be ruled out. The strength and persistence of the event suggested this was not the result of contamination. [7] The authors of the original study did later revisit and postulate that there were other possible sources and mechanisms for the entrainment and release of water vapour from Apollo 14's ascent stage. [8] While the origins of the water detected by Apollo 14 remain in dispute, the presence of water on the Moon has been confirmed through direct observation by the Stratospheric Observatory for Infrared Astronomy [10] and the Moon Mineralogy Mapper instrument on board Chandrayaan-1. [11] [12] A 2008 study of lunar rock samples revealed evidence of water molecules trapped in volcanic glass beads. [13] A similar study showed how the Moon's solar wind–driven processes could entrain this on the Moon's surface. [14]
Apollo 12 was the sixth crewed flight in the United States Apollo program and the second to land on the Moon. It was launched on November 14, 1969, by NASA from the Kennedy Space Center, Florida. Commander Charles "Pete" Conrad and Lunar Module Pilot Alan L. Bean performed just over one day and seven hours of lunar surface activity while Command Module Pilot Richard F. Gordon remained in lunar orbit.
Apollo 14 was the eighth crewed mission in the United States Apollo program, the third to land on the Moon, and the first to land in the lunar highlands. It was the last of the "H missions", landings at specific sites of scientific interest on the Moon for two-day stays with two lunar extravehicular activities.
Apollo 16 was the tenth crewed mission in the United States Apollo space program, administered by NASA, and the fifth and penultimate to land on the Moon. It was the second of Apollo's "J missions", with an extended stay on the lunar surface, a focus on science, and the use of the Lunar Roving Vehicle (LRV). The landing and exploration were in the Descartes Highlands, a site chosen because some scientists expected it to be an area formed by volcanic action, though this proved not to be the case.
Apollo 17 was the eleventh and final mission of NASA's Apollo program, the sixth and most recent time humans have set foot on the Moon or traveled beyond low Earth orbit. Commander Gene Cernan and Lunar Module Pilot Harrison Schmitt walked on the Moon, while Command Module Pilot Ronald Evans orbited above. Schmitt was the only professional geologist to land on the Moon; he was selected in place of Joe Engle, as NASA had been under pressure to send a scientist to the Moon. The mission's heavy emphasis on science meant the inclusion of a number of new experiments, including a biological experiment containing five mice that was carried in the command module.
Nozomi was a Japanese Mars orbiter that failed to reach Mars due to electrical failure. It was constructed by the Institute of Space and Astronautical Science, University of Tokyo and launched on July 4, 1998, at 03:12 JST with an on-orbit dry mass of 258 kg and 282 kg of propellant. The Nozomi mission was terminated on December 31, 2003.
Explorer 35,, was a spin-stabilized spacecraft built by NASA as part of the Explorer program. It was designed for the study of the interplanetary plasma, magnetic field, energetic particles, and solar X-rays, from lunar orbit.
A Moon landing or lunar landing is the arrival of a spacecraft on the surface of the Moon. This includes both crewed and robotic missions. The first human-made object to touch the Moon was the Soviet Union's Luna 2, on 13 September 1959.
Lunar water is water that is present on the Moon. Diffuse water molecules in low concentrations can persist at the Moon's sunlit surface, as discovered by the SOFIA observatory in 2020. Gradually, water vapor is decomposed by sunlight, leaving hydrogen and oxygen lost to outer space. Scientists have found water ice in the cold, permanently shadowed craters at the Moon's poles. Water molecules are also present in the extremely thin lunar atmosphere.
The magnetic field of the Moon is very weak in comparison to that of the Earth; the major difference is the Moon does not have a dipolar magnetic field currently, so that the magnetization present is varied and its origin is almost entirely crustal in location; so it's difficult to compare as a percentage to Earth. But, one experiment discovered that lunar rocks formed 1 - 2.5 billion years ago were created in a field of about 5 microtesla (μT), compared to present day Earth's 50 μT. During the Apollo program several magnetic field strength readings were taken with readings ranging from a low of 6γ (6nT) at the Apollo 15 site to a maximum of 313γ (0.31μT) at the Apollo 16 site, note these readings were recorded in gammas(γ) a now outdated unit of magnetic flux density equivalent to 1nT.
The Lunar Atmosphere and Dust Environment Explorer was a NASA lunar exploration and technology demonstration mission. It was launched on a Minotaur V rocket from the Mid-Atlantic Regional Spaceport on September 7, 2013. During its seven-month mission, LADEE orbited the Moon's equator, using its instruments to study the lunar exosphere and dust in the Moon's vicinity. Instruments included a dust detector, neutral mass spectrometer, and ultraviolet-visible spectrometer, as well as a technology demonstration consisting of a laser communications terminal. The mission ended on April 18, 2014, when the spacecraft's controllers intentionally crashed LADEE into the far side of the Moon, which, later, was determined to be near the eastern rim of Sundman V crater.
The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic missions to the Moon. Its detailed mapping program is identifying safe landing sites, locating potential resources on the Moon, characterizing the radiation environment, and demonstrating new technologies.
Energetic Neutral Atom (ENA) imaging, often described as "seeing with atoms", is a technology used to create global images of otherwise invisible phenomena in the magnetospheres of planets and throughout the heliosphere.
The Apollo Lunar Surface Experiments Package (ALSEP) comprised a set of scientific instruments placed by the astronauts at the landing site of each of the five Apollo missions to land on the Moon following Apollo 11. Apollo 11 left a smaller package called the Early Apollo Scientific Experiments Package, or EASEP.
The Far Ultraviolet Camera/Spectrograph (UVC) was one of the experiments deployed on the lunar surface by the Apollo 16 astronauts. It consisted of a telescope and camera that obtained astronomical images and spectra in the far ultraviolet region of the electromagnetic spectrum.
The Charged Particle Lunar Environment Experiment (CPLEE), placed on the lunar surface by the Apollo 14 mission as part of the Apollo Lunar Surface Experiments Package (ALSEP), was designed to measure the energy spectra of low-energy charged particles striking the lunar surface. It measured the fluxes of electrons and ions with energies from 40 eV to 20 keV. The primary purpose of the experiment was to examine plasma particles originating from the Sun and the low-energy particle flux in the Earth's magnetic tail.
Chandrayaan-3 is the third mission in the Chandrayaan programme, a series of lunar-exploration missions developed by the Indian Space Research Organisation (ISRO). The mission consists of a lunar lander named Vikram and a lunar rover named Pragyan, similar to those launched aboard Chandrayaan-2 in 2019.
The Cold Cathode Gauge Experiment, also known as the Lunar Atmosphere Detector, was a scientific package that flew on board Apollo 12, Apollo 13, Apollo 14, and Apollo 15. The goal of the experiment was to measure the density of the Moon's tenuous atmosphere, but not its composition.
The Lunar Atmospheric Composition Experiment (LACE) was a miniature magnetic deflection mass spectrometer. The experiment's aim was to study the composition and variations of the lunar atmosphere. The only deployment of LACE was as part of the Apollo Lunar Surface Experiments Package (ALSEP) on Apollo 17 within the Taurus–Littrow valley.
The Solar Wind Spectrometer was a scientific package that flew on the Apollo 12 and Apollo 15 missions to the surface of the Moon. The goal was to characterise the solar wind near the Moon's surface and to explore its interactions with the lunar environment. The experiments' principal investigator was Dr Conway W. Snyder of the Jet Propulsion Laboratory.
The Lunar Ejecta and Meteorites Experiment (LEAM) was a lunar science experiment that flew to the Moon on board Apollo 17 in 1972. It collected information on dust particles produced as a result of meteoroid impacts on the surface of the Moon.
| Launch vehicles | |
|---|---|
| Launch vehicle components | |
| Spacecraft | |
| Spacecraft components | |
| Space suits | |
| Lunar surface equipment |
|
| Ground support | |
| Ceremonial | |
| Related | |
