THE LAUNCHED DART!

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.

Ciao!

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]

ONE YEAR WITH A COMET!

Comet 67P/Churyumov–Gerasimenko and its ESA's buddies, Rosetta and Philae (by sciencemug)

One year with a comet!
Un anno con la cometa!

KEPLER, SANTA BERNARD AND THE XMAS TALE (PT1/2)

KEPLER, SANTA BERNARD AND THE XMAS TALE
-A COSMIC XMAS TALE-

(Part1/2)

(Part 2/2 is here)

(The podcast)

in Eng?ish

Stardate 4223.13: the sky's pitch black, the universe is even more ancient, the sidereal cold's famished. A shy glow on a bare thirsty spot of land tries to fight darkness. It's helped by its allies, the strange sounds coming from a dozen creatures. There's a bigger one, name's Santa Bernard, emitting lower notes. In front of him/her/it, the rest of 'em, kinda cooing [kinda], crouched down in a semicircle.

 

Santa Bernard and the jellies (by sciencemug)

Santa Bernard- Well jellies [pet name for alien 'kids' which are the human equivalent of a mix of a mutant squid, a bag of dirty socks and a fatter version of a crimson Shrek seriously addicted to napalm] this is the story of how the Cosmic Xmas Tree was finally decorated with its most precious ornament, the 'Ridiculously Low Albedo Ball'.
The jellies kinda make [kinda] a loud- Oooohhh... - and then- Santa Bernard?
SB- Yes?
js- What does albedo mean?
SB- Well, little bunch of atoms and quantum stuff, when light hits a celestial body, be it a planet, a comet or an Emily Ratajkowski, a fraction of that light's reflected by that body. The albedo is the ratio of the reflected light to the hitting (incident) light. The lower the albedo, the darker the celestial body. Gotcha?
js- YEEEES!-
SB- Good. Now...
One of the jellies, Bob, rises one of its... extremities[?] and- Santa Bernard...
SB- Yes Bob?
Bo- What's an Emily Ratajkowski?
SB- It's both a hot celestial body of a distant galaxy and a universal measure unit for a 1 to 14 aH (Astral Hottness) scale, where 1ER means a Sacha Baron Cohen in a tiny tiny micro-bikini (and before you ask, the answer is: a nasty nasty thing) and 14ERs mean, well, Emily Ratajkowski. Ok? Can I start telling the story now?
Jellies kinda nod [kinda]
SB- Good, listen up then. Once upon a time, in a planet far far away, a baby spacecraft was born from its mama-NASA. The baby probe name was Kepler and Kepler at its birth weighed 1052.4 kilograms [yup, aliens are smart, hence they use the SI] and was about 2.7 meters in diameter and 4.7 meters high. Besides, thanks to its 10.2 square meters wide panels, Kepler could feed on what its grandad (the star of that system, Mr. Sol AKA the Sun) was giving it: a slice of the electromagnetic radiation cake.
Kepler was a solitary kid-probe, indeed it left [March 6, 2009] grandma planet-Earth (with its mama-NASA's blessing) at its birth, and went to live around Mr. grandpa Sol. I mean, literally around the Sun: Kepler was loitering in a Sol-centered orbit and its year was 371 days long.
One of the jellies kinda squeal [kinda]- Santa Bernard, wasn't Kelper scared to be all alone?
- Kepler Charlotte, its name was Kepler - Santa Bernard answers the question with what can be considered an alien grin (or the manifestation of a slight stroke in association with a violent rash caused by an almost lethal exposition to a gamma ray burst and/or a "Lord of the Ring" marathon) on what can be considered an alien face (or a battlefield where nightmares of endless generations of seriously deranged werewolves fought a raging war against cholesterol and silver bullets budding from a parallel universe where they were garlic coated square donuts) - and no dear, our little spacecraft wasn't scared to be all alone out in the space, on the contrary, it was very happy like that. And I'll tell you why.
Since ever, Xmas had been the happiest part of the years for Kepler, of its own and of its grandma-Earth's. Therefore Kepler's deeper and most secret desire had always been to find the ultimate piece of ornament for the Cosmic Xmas Tree, the ultimate space Xmas ball. And Kepler needed to be alone, in a quiet place, to better concentrate for its mission. Because this mission was a very very, very difficult one, since our kid-probe had to face the competition of the other members of its extended family of human made space objects. 

Kepler and grandpa by sciencemug

And they were so many. And so good at their jobs...
There was his big brother, for a start, the beloved Hubble telescope (or was it a cousin, Kepler wasn't quite sure since Hubble had gotten space-DNA straight from both mama-NASA and aunt-ESA) which had collected the stunning lights for the CXT in the shapes of nebulae and galaxies since nineteen years before Kepler's birth. His bro Cassini-Huygens (or cousin, again, Kepler didn't know for sure since C-H got spacecraft-genes straight from mama-NASA, aunt-ESA and aunt-ASI) had spent ten years providing wonderful silvery rings and Saturn and Saturn's moons balls to the CXT. The dead sibling Galileo, may it rest in peace, had passed away six years before Kepler's birth, but only after a fourteen years long life during which it had decorated the CXT with amazing Jupiter reddish-orange balls and even provided fireworks made out of a comet crash onto the giant planet-ball. And, then, the other brother, spacecraft Messenger, that for more than a decade had been an authentic maker of Mercury balls. Another young sibling, Curiosity, in just two years had dug all the martian stylish red dust that was usually spread on the CXT to embellish it. Not to mention the heroic cousin, Rosetta (aunt-ESA's most famous daughter) and its son Philae: after a ten years trip and a three years hibernation/coma, they had just catched the SHOOTING STAR* to put on top of the Cosmic Xmas Tree!
Ah, definitely, so many of them. And so so good at their jobs. And just think, these ones were only a fraction of Kepler's family.
Jellies look saddened- Poor Kepler, it's not going to make it, it won't find the perfect ornamental ball for the Xmas tree of the universe before the others- they kinda whine [kinda] all together
SB- Well, my sweet collection of nuclear forces and probabilities, Kepler thought otherwise. It was a very driven kid-spacecraft and it knew it would have found the perfect space Xmas ball if it had kept following its machine-soul, its programming, and looking for exoplanets...
js- Whaaaat?
SB- Planets outside Kepler's grandpa's garden, the Solar System. Kepler searched for these extrasolar planets peeping the Cygnus-Lyra region, a piece of Kepler's grandma-Earth's northern sky stuffed with stars and therefore potential planets. And therefore potential perfect CXT's balls. Kepler couldn't help but staring at that spot of the universe, observing 100,000 stars at the same time, stars that were from few to thousands of light years far away. It did it constantly, restlessly, stubbornly, since its birth. And Kepler chose to live in a specific solitary orbit around Mr. Sol not only to easily concentrate, but also because it had so gained a clean view of its adored chunk of cosmos. In that orbit, in fact, nothing (neither Mr. Sol, nor grandmother Earth or great aunt Moon) could hinder Kepler observation. Not even for a microsecond.
Jellies cheer up a bit now and get closer to Santa B. But one of them, Solomon, is a bit hesitant, and SB notices it
SB- What's up buddy?- asks with a whistle-like sound
So- I don't get it, Santa B. You said Kepler was looking for planets, but you also said that it was observing stars... How could it find planets by staring at the stars?
SB- Aaah, this is a very good question pal. Excellent! - Solomon kinda blush [kinda] - I'll let you hear the answer directly from a page of mother-NASA's diary: "[Kepler] simultaneously measures the variations in the brightness of more than 100,000 stars every 30 minutes, searching for the tiny "winks" in light output that happen when a planet passes in front of its star." Before you ask, Solomon and jellies, Kepler could perceive and quantify those tiny winks thanks to its only inner organ-instrument, the photometer (or light meter). But let's go back to mom-NASA's diary: "The effect [of the winks] lasts from about an hour to about half a day, depending on the planet’s orbit and the type of star [...]  [and Kepler is born] to detect these [winks, these] changes in the brightness of a star when a planet crosses in front of it, or “transits the star.” This is called the “transit method” of finding planets".
Got it? 
js- YEEEES!
SB- Good, little loaves of hadrons. Now it's nap time.
js- Noooooooo, we want to hear the rest of the story, please Santa Bernard!
SB- Shush shush. Time to rest...

Merry Xmas from Santa Bernard and sciencemug

*Comet 67P/Churyumov–Gerasimenko