Have you ever considered what might happen if an asteroid were to collide with our planet? Did you believe that such a scenario could indeed happen after seeing a movie like Armageddon? That’s why we have to study asteroids.
Moreover, a million asteroids have been discovered as of today. Every few years, this number grows by hundreds of thousands. It is, however, considerably more challenging to analyze asteroids up close than it is to discover them. Only about 20 asteroids have been visited by spacecraft thus far. Only six of them were investigated in depth by dedicated missions; the rest were ‘bonus’ flybys by spacecraft such as Galileo and Rosetta on their way to their primary destinations.
While it is plausible to believe that most asteroids are similar, there are considerable differences across groups based on their origin, composition, history, and other factors.
At this time, asteroids are examined in two different ways. First, use ground-based and space telescopes to observe distant, typically point-source events. Second, close-range observation, in-situ measurements, and sample return via space missions.
The first way allows us to analyze thousands of objects with a single instrument, giving us a better understanding of asteroids’ orbits, albedos (how well a surface reflects solar energy), colors, spectra, and sizes. More information about asteroids can be obtained from space missions, such as maps of albedos, colors, spectra, and morphological features (craters, faults, fractures, boulders, and so on); 3D models; precise mass and density estimates; overviews of physical properties and chemical composition of surface materials; and hints about an asteroid’s internal composition.
With various instruments, a single spacecraft can examine only one or, in certain situations, a few objects in great detail. On the other hand, Monolithic missions are unsuitable for studying tens or hundreds of asteroids.
Multi-Asteroid Touring (MAT) is the solution
Multi-Asteroid Touring Mission – a fleet of tiny spacecraft can visit many asteroids and collect remote measurements of far more objects than have hitherto been analyzed at close range. Asteroids of various families, spectral kinds, sizes, and other classes can be visited.
Designing a spacecraft
From a thrust standpoint, the MAT nano-spacecraft’s biggest difficulty is its mass limitation. The number and length of tethers, applied voltage, and mass of a spacecraft driven by the E-sail (E-sail concept – a propellant-less propulsion system would harness the solar wind to travel into interstellar space) have a strong relationship with the acceleration of the spacecraft. The E-sail of the MAT idea is made up of a single tether with a maximum length of 20 kilometers. The mass is the sole variable parameter left. To reach the main asteroid belt in one heliocentric orbit, the spacecraft’s mass must be kept under 6 kg.
Work in the future
The conservative approach of recycling previously flown technologies is one reason why all previous and continuing asteroid missions have employed pricey monolithic spacecraft. The MAT concept encompasses multiple technologies that have yet to be demonstrated in space.