ASTER is a planned space mission under development by the Brazilian Space Agency that will launch a spacecraft to orbit a

near-Earth object A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun ( perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit a ...

known as , a triple asteroid system. The launch is scheduled for 2025, with a rendezvous in 2024/2027. According to de Brum et al. 2021, the launch is planned for June 2022 (asteroid arrival in December 2024) or June 2025 (arrival September 2027). The mission is not on the list of projects considered by the AEB for the 2022-2031 period. Nor was the list of projects from 2005-2014 or 2012-2021.

Overview

Brazil is promoting

STEM Stem or STEM most commonly refers to: * Plant stem, a structural axis of a vascular plant * Stem group * Science, technology, engineering, and mathematics Stem or STEM can also refer to: Language and writing * Word stem, part of a word respon ...

at its universities and technological industries by engaging in the first Brazilian deep space mission and developing all the science instrument payloads, attitude control and navigation systems, as well as solar electric propulsion. The mission was originally intended in 2010 for a 2014 launch,ASTER Mission: First Brazilian Deep Space Mission, planned to be launched in 2014. The Aster Project: Flight to a Near Earth Asteroid. A. A. Sukhanov, H. F. DE C. Velho, E. E. Macau, O. C. Winter. ''Cosmic Research'', 2010, Vol. 48, No. 5, pp. 443–450 then pushed back to 2015, to 2020, and is currently set for launch in 2022/2025. As of 2017, the estimated budget is of US$60 million. The spacecraft is designed around the small Russian-Finnish spacecraft bus known as MetNet,Reviewed plan of the ALR, the laser rangefinder for the ASTER deep space mission to the triple asteroid 2001-SN263
A. G. V. de Brum, F. C. da Cruz. XVIII Brazilian Colloquium on Orbital Dynamics (2016). ''Journal of Physics'': Conf. Series 911 (2017) with a total fueled mass of . The spacecraft features four solar electric thrusters developed by Brazil. The engines are Hall effect thrusters powered by solar panels made out of

gallium arsenide Gallium arsenide (GaAs) is a III-V direct band gap semiconductor with a Zincblende (crystal structure), zinc blende crystal structure. Gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monoli ...

that are capable of generating up to 2.1 kW.Preliminary Development Plan of the ALR, the Laser Rangefinder for the ASTER Deep Space Mission to the 2001 SN263 Asteroid ''(Archived)''
(PDF) Antonio Gil Vicente de Brum. 2011. From this, 110 W will be available to science instruments. The target is , a triple asteroid system in the Amor asteroid group. The ASTER mission team leaders are Antonio Gil Vicente de Brum, Marcelo Assafin, Flávio C. Cruz, and Álvaro Alberto Cuccolo.

Objectives

The primary objective of ASTER project is to promote

science, technology, engineering, and mathematics Science, technology, engineering, and mathematics (STEM) is an umbrella term used to group together the distinct but related technical disciplines of science, technology, engineering, and mathematics. The term is typically used in the context of ...

(STEM) at its universities and technological industries by engaging in the first Brazilian deep space mission. Since 2010, Brazil has been developing the desired science instrument payloads, attitude control and navigation systems, as well as a novel solar electric propulsion engine with reduced energy requirements. The science objectives include measurements of the bulk properties of the triple asteroid system (size, shape, volume, density, dynamics, spin state, and rotation speed), the internal properties (structure, mass distribution, gravitational field) and surface properties (mineral composition, morphology, elemental composition). ASTER may carry an

astrobiology Astrobiology (also xenology or exobiology) is a scientific field within the List of life sciences, life and environmental sciences that studies the abiogenesis, origins, Protocell, early evolution, distribution, and future of life in the univ ...

experiment to determine the viability of some selected microorganisms in deep space, and it may also measure the deep space plasma environment along the trajectory.

Science payload

The science payload consists of: * Imaging Camera, a multispectral camera with wide and narrow-band * Laser rangefinder, called ASTER Laser Rangefinder (ALR), will map the surface and texture of the target asteroids, and perform a

geodesic In geometry, a geodesic () is a curve representing in some sense the locally shortest path ( arc) between two points in a surface, or more generally in a Riemannian manifold. The term also has meaning in any differentiable manifold with a conn ...

and geophysical characterization with a ≤10 m precision. Its mass is <5 kg, and the power required is < 20 W * Infrared spectrometer, to determine surface composition *

Mass spectrometer Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is us ...

, to determine the asteroid surface composition *

Synthetic aperture radar Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or 3D reconstruction, three-dimensional reconstructions of objects, such as landscapes. SAR uses the motion of the radar antenna over a target regi ...

(SAR), to produce two-dimensional images or three-dimensional reconstructions of the asteroids * Along the trajectory, some

microbiology Microbiology () is the branches of science, scientific study of microorganisms, those being of unicellular organism, unicellular (single-celled), multicellular organism, multicellular (consisting of complex cells), or non-cellular life, acellula ...

experiments may be performed to measure microorganisms' survival in deep space.

Solar electric propulsion

The spacecraft features a type of solar electric propulsion based on the Hall effect thruster. The thruster was developed by the Plasma Physics Laboratory at the

University of Brasília A university () is an institution of tertiary education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase , which roughly means "community of teachers and scholars". Uni ...

(LFP-UnB). The engineers created a modification that employs an array of

permanent magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, c ...

s to produce a radial magnetic field inside the plasma channel of the thruster to accelerate the

xenon Xenon is a chemical element; it has symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...

propellant ions and generate thrust. Bench tests in vacuum indicate that the use of permanent magnets reduces the electrical power consumption by 30%, which allows for the use of smaller and lighter solar panels. The Brazilian engineers named it Permanent Magnet Hall Thruster, or PMHT. The spacecraft architecture plans to mount four PMHT plasma thrusters, where two will be spares. All four thrusters operating simultaneously produce 160 mN, although the ASTER mission can be performed with thrust in the interval between 80 mN to 120 mN of total thrust. The spacecraft will be launched to

low Earth orbit A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...

(approximately 400 km altitude), where it will then use its plasma thrusters to increase its speed and raise its elliptical orbit until it reaches

escape velocity In celestial mechanics, escape velocity or escape speed is the minimum speed needed for an object to escape from contact with or orbit of a primary body, assuming: * Ballistic trajectory – no other forces are acting on the object, such as ...

for an heliocentric transfer to the asteroid. Complex modeling was done to determine techniques to safely orbit the triple system at close range.ASTER Mission: Stability regions around the triple asteroid 2001 SN263
(PDF) O. C. Winter, R. A. N. Araujo, A. F. B. A. Prado, A. Sukhanov. 2011

Target asteroid system

The triple asteroid system is a carbonaceous (

C-type asteroid C-type (carbonaceous ) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks ...

) from the Amor asteroid group.ASTER: A Brazilian Mission to an Asteroid.
(PDF) O. C. Winter, E. E. N. Macau, H. de Campos Velho, V. Carruba1, and the Scientific and Engineering Payload ASTER Team. Such asteroids hold clues of the initial stages of planetary formation and also the origin of water and

abiogenesis Abiogenesis is the natural process by which life arises from non-living matter, such as simple organic compounds. The prevailing scientific hypothesis is that the transition from non-living to living entities on Earth was not a single even ...

on Earth. The main central body is an irregular object with a diameter about 2.8 km, while the other two are small objects 1.1 km and 0.4 km across.The ASTER Mission: Exploring for the First Time a Triple System Asteroid.
(PDF) Elbert E.N. Macau, Othon Winter, Haroldo Fraga de Campos Velho. January 2011

References

{{Future spaceflights Missions to near-Earth asteroids Missions to asteroids Space program of Brazil