The Fine-Resolution Epithermal Neutron Detector (FREND) is a

neutron detector Neutron detection is the effective detection of neutrons entering a well-positioned detector. There are two key aspects to effective neutron detection: hardware and software. Detection hardware refers to the kind of neutron detector used (the most ...

that is part of the instrument payload on board the

Trace Gas Orbiter The ExoMars Trace Gas Orbiter (TGO or ExoMars Orbiter) is a collaborative project between the European Space Agency (ESA) and the Russian Roscosmos agency that sent an atmospheric research orbiter and the ''Schiaparelli'' demonstration lander ...

(TGO), launched to

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmos ...

in March 2016. This instrument is currently mapping

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

levels to a maximum depth of beneath the Martian surface, thus revealing shallow water ice distribution. This instrument has an improved resolution of 7.5 times over the one Russia contributed to NASA's ''

2001 Mars Odyssey ''2001 Mars Odyssey'' is a robotic spacecraft orbiting the planet Mars. The project was developed by NASA, and contracted out to Lockheed Martin, with an expected cost for the entire mission of US$297 million. Its mission is to use spectr ...

'' orbiter.

Overview

FREND can provide information while orbiting Mars on the presence of hydrogen, in the form of

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...

or hydrated minerals in the top of the Martian surface. FREND also features a

dosimeter A radiation dosimeter is a device that measures dose uptake of external ionizing radiation. It is worn by the person being monitored when used as a personal dosimeter, and is a record of the radiation dose received. Modern electronic personal dos ...

to monitor the radiation environment along its orbit around Mars.

Objectives

The main science objective of the instrument is to carry out high spatial resolution mapping of epithermal and fast neutron fluxes from the Martian surface. FREND will work in synergy and complement orbital and ground data as measured the

Dynamic Albedo of Neutrons The Dynamic Albedo of Neutrons (DAN) instrument is an experiment mounted on the Mars Science Laboratory ''Curiosity'' rover. It is a pulsed sealed-tube neutron source and detector used to measure hydrogen or ice and water at or near the Marti ...

(DAN) instrument on the ''Curiosity'' rover, the

ADRON-RM ADRON-RM (Autonomous Detector of Radiation of Neutrons Onboard Rover at Mars) is a neutron spectrometer to search for subsurface water ice and hydrated minerals. This analyser is part of the science payload on board the European Space Agency ...

instrument on the ''Rosalind Franklin'' rover and the ADRON-EM on the

Kazachok The ExoMars ''Kazachok'' ( rus, Казачок; formerly ExoMars 2020 Surface Platform) was a planned robotic Mars lander led by Roscosmos, part of the ExoMars 2022 joint mission with the European Space Agency. ''Kazachok'' translates as "Litt ...

. The second goal of FREND is to use its

to measure the radiation dose at the TGO orbit from energetic particles of

galactic cosmic ray Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...

s and

solar flare A solar flare is an intense localized eruption of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and other sola ...

s. The data will be used to estimate exposure levels of spacecraft and maintain radiation safety of crewed interplanetary flights.

Principle and development

Cosmic ray Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our ow ...

s are sufficiently energetic to break apart atoms in the top one or two metres of Mars' surface, releasing high-energy neutrons, which can be measured by FREND instrument. The distribution of neutron velocities measured reveals the hydrogen content, which are a good indicator of hydrogen abundance —water or hydrated minerals— in the shallow subsurface of Mars. FREND uses inherited technology developed by the

Russian Space Research Institute The Russian Space Research Institute (russian: Институт космических исследований Российской академии наук, Space Research Institute of the Russian Academy of Sciences, SRI RAS, Russian abbrevi ...

and flown on the High Energy Neutron Detector (HEND) on ''

Mars Odyssey ''2001 Mars Odyssey'' is a robotic spacecraft orbiting the planet Mars. The project was developed by NASA, and contracted out to Lockheed Martin, with an expected cost for the entire mission of US$297 million. Its mission is to use spectr ...

''; the Mercury Gamma and Neutron Spectrometer (MGNS) on ''

BepiColombo BepiColombo is a joint mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) to the planet Mercury. The mission comprises two satellites launched together: the Mercury Planetary Orbiter (MPO) and ''Mio'' ...

''; the Lunar Exploration Neutron Detector (LEND) on the ''

Lunar Reconnaissance Orbiter 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 ...

'', and

(DAN) on ''Curiosity'' rover. This instrument's key components are four detectors containing

Helium-3 Helium-3 (3He see also helion) is a light, stable isotope of helium with two protons and one neutron (the most common isotope, helium-4, having two protons and two neutrons in contrast). Other than protium (ordinary hydrogen), helium-3 is th ...

for neutrons with energies from 0.4 keV to 500 keV, and a stilbene-based

scintillator A scintillator is a material that exhibits scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate (i.e. re-emit the absorbe ...

for high-energy neutrons up to 10 MeV. Each of the four ³He detectors counts neutrons independently for increased reliability. All five detectors are encased within a

collimator A collimator is a device which narrows a beam of particles or waves. To narrow can mean either to cause the directions of motion to become more aligned in a specific direction (i.e., make collimated light or parallel rays), or to cause the spat ...

that improves the resolution 7.5 times over the one Russia contributed to NASA's ''Mars Odyssey'' orbiter. The Principal Investigator is Igor G. Mitrofanov, from the

(IKI). Mitrofanov is also the PI for ExoMars'

and ADRON-EM neutron detector instruments.

References

{{Use British English, date=July 2018 ExoMars Mars imagers Astrobiology Space science experiments

Overview

Objectives

Principle and development

See also

References