Buffer Me

Wednesday, November 24, 2021


DART spacecraft communicates with NASA (by @sciencemug)
DART spacecraft communicates with NASA (by @sciencemug)
[NASA logo pic, the DART spacecraft pic and the starry background pic are in the public domain
(source: Wikimedia Commons); adapted by @sciencemug]


Soo, dear reader, today (24-Nov-2021) the DART (Double Asteroid Redirection Test) Mission launched. Developed and led for NASA by the Johns Hopkins Applied Physics Laboratory (APL), DART launched at 6:21 p.m. GMT, from the Space Launch Complex 4 East at Vandenberg Space Force Base in California, USA. The payload was carried by a SpaceX Falcon 9 rocket.

The mission falls under the umbrella of NASA's Planetary Defense Coordination Office (PDCO), and it is the first test of "the kinetic impactor technique to change the motion of an asteroid in space" (see). In other words the NASA's brains, on behalf of humanity, will try, for the first time ever, to hit a space object with a man-made object in order to change its (the space one's, that is) course, and therefore to see if this is a sound strategy for preventing the Earth from getting hit by a space rock et al, and related havoc.

The DART mission's target is a 160 meters in size moonlet, Dimorphos, that orbits, at just over one km distance, the 780 meters in diameter near-Earth asteroid (65803), aka Didymos. So, Didymos and Dimorphos are a binary system, and DART spacecraft "will intercept [Dimorphos] in late September 2022, when the Didymos system is within 11 million kilometers of Earth" (see).

Although its innovative solar panels (the Deployable Space Systems Roll-Out Solar Arrays, aka ROSA, that, by DART, are going to be deployed in deep space for the first time) measure 8.6 meters by 2.3 meters, DART spacecraft per se has just the dimensions of a small US car (that is, probably, of a big European car...). But DART will strike the binary system at the impressive velocity of about 6.6 Km/s (meaning roughly 24000 Km/h or, for you, stubborn impractical non-SI users, 14800 miles per hour), meaning 20 or so times the speed of sound, meaning, dear reader, that, when the hit happens, a looot of energy will be released up there! 

This impact generated energy, scientist think, will indeed be enough to "change the speed of the moonlet in its orbit around the main body [i.e. Didymos] by a fraction of one percent, but this will change the orbital period of the moonlet by several minutes - enough to be observed and measured using telescopes on Earth" (see). In other words, the event will be powerful enough to eventually change the asteroid system's course, and, ultimately, it will prove that the kinetic impactor technique can be used with success to deflect something similar to Didymos that, unlike it and its tiny satellite, be someday actually rushing toward Earth.

By the way, dear, reader, the whole smash&crash fuss will be witnessed, at close but safe distance, by the small LICIACube CubeSat (Light Italian Cubesat for Imaging of Asteroids) built by the Italian Space Agency (ASI), and released by DART spacecraft itself shortly before its rough demise.

The DART spacecraft, besides, is packed with state-of-the-art tech, like its NASA’s Evolutionary Xenon Thruster — Commercial (NEXT–C) ion engine, an electric propulsion system, its SMART Nav navigation algorithm for real time autonomous targeting of the Didymos system, and, last but not at all least, its only instrument, the Didymos Reconnaissance and Asteroid Camera for Optical navigation, aka DRACO. This is a camera that will take fancy pics of the asteroid system ("better than 20 cm/pixel at impact" (see)), but, above all, that, right before the impact, will feed the SMART NAV the necessary images to choose the right target, that is to identify and distinguish between Dimorphos (to hit) and Didymos (not to hit).

Well, dear reader, that's all for now. Let's wish DART mission's success, so that y'all, on Earth, be a little bit safer!

The comics are a rendering of what this dumb blog figures NASA's and DART spacecraft's communications have probably been, and will possibly be.


DART spacecraft communicates with NASA nad bets (by @sciencemug)
DART spacecraft communicates with NASA (by @sciencemug)
[NASA logo pic and the DART spacecraft & asteroids pic are in the public domain
(source: Wikimedia Commons); the target pic by Karen Arnold
is under the CC0 Public Domain license, (source: Public Domain Pictures); adapted by @sciencemug]