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 mos ...

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 lande ...

(TGO), launched to

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

in March 2016. This instrument is currently mapping

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

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 spectro ...

'' orbiter.

Overview

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

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

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

dosimeter A radiation dosimeter is a device that measures the equivalent dose, 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 el ...

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), ''Curiosity'' rover. It is a pulsed sealed-tube neutron source and detector used to measure hydrogen or ice and water at or ...

(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'' (; 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 "Little Cossack", and is ...

. The second goal of FREND is to use its

to measure the radiation dose at the TGO orbit from energetic particles of galactic cosmic rays and

solar flare A solar flare is a relatively intense, localized emission 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 ot ...

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 or astroparticles 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 ...

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 (; SRI RAS, Russian abbreviation: ИКИ РАН, IKI RAN) is the leading organization of the Russian Academy of Sciences on space exploration to benefit fundamental science. It was formerly known as the Space ...

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 spectro ...

''; 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 orbit, polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic ...

'', 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. (In contrast, the most common isotope, helium-4, has two protons and two neutrons.) Helium-3 and hydrogen-1 are the only stable nuclides with ...

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 ab ...

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