NASA’s Double Asteroid Redirection Test (DART)

[PointOfViewGun]

NASA, SpaceX Launch DART: First Test Mission to Defend Planet Earth

NASA’s Double Asteroid Redirection Test (DART), the world’s first full-scale mission to test technology for defending Earth against potential asteroid or comet hazards, launched Wednesday at 1:21 a.m. EST on a SpaceX Falcon 9 rocket from Space Launch Complex 4 East at Vandenberg Space Force Base in California.

Just one part of NASA’s larger planetary defense strategy, DART – built and managed by the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland – will impact a known asteroid that is not a threat to Earth. Its goal is to slightly change the asteroid’s motion in a way that can be accurately measured using ground-based telescopes.

DART will show that a spacecraft can autonomously navigate to a target asteroid and intentionally collide with it – a method of deflection called kinetic impact. The test will provide important data to help better prepare for an asteroid that might pose an impact hazard to Earth, should one ever be discovered. LICIACube, a CubeSat riding with DART and provided by the Italian Space Agency (ASI), will be released prior to DART’s impact to capture images of the impact and the resulting cloud of ejected matter. Roughly four years after DART’s impact, ESA’s (European Space Agency) Hera project will conduct detailed surveys of both asteroids, with particular focus on the crater left by DART’s collision and a precise determination of Dimorphos’ mass.

This is simply monumental. It's very encouraging to see programs like this advance. They're not just testing a planetary defense theory, but also the new Evolutionary Xenon Thruster (NEXT), Roll Out Solar Array (ROSA) design, and Small-body Maneuvering Autonomous Real Time Navigation (SMART Nav) system.

It got launched today:





Might not be enough to warrant a discussion but developments like this certainly deserve the spotlight. They help us to advance technologies that can help us get to other planets at least in our solar system and keep them safe. Let's talk about planetary defense options and whether such tests can trigger consequences we can not change. What do you think?

[Flinn]

What do you think?

That something is better than nothing. Such a mission has indeed some scientific values, but IMO this is more propaganda than anything else. I really doubt we have the means to really affect anything but the smallest asteroids.

[PointOfViewGun]

Small details can have big effects especially in the vastness of space.

[Cyclops]

Pls don't land anything on Australia, you will get another littering fine.

Jokes aside, this is great.

[Flinn]

Small details can have big effects especially in the vastness of space.

Indeed

Anyways, it's really difficult to do any kind of speculation here, I mean the real reach of the phenomenon is of course speculative, i.e. even about the Late Heavy Bombardment there's not unanimity in the scientific community, and that's supposedly one of the most important event of Earth's history. This is of course due to the lack of direct observation and historical documents (because of huge time scales) and only the biggest impacts left some marks which are still recognizable as of today (and not all of them anyways, since the oldest one have been most probably deleted by the tectonic movements), but in human scales even the average and small asteroids/comets have the potentiality to bring havoc to our civilization and possibly end it for good (mostly due to climate change than actual destruction caused by the impact, that is).

The table below shows a prevision, with time scales, for the small and average impacts (included airbursts, i.e. like the Tunguska event or the more recent Chelyabinsk event).



The table above is sourced from Wikipedia, in this this page it is possible to find quite a lot of info about impact events, if one is curious to learn more.

However, those are only the small and average ones, still they can indeed be very destructive and even the smallest ones can wreck anything locally: recently it has been proved that the city of Tall el-Hamman has been destroyed by an airbust explosion, sometimes around 3,600 year ago, and that might have inspired the Biblical story of Sodom and Gomorrah. Imagine what the largest ones could do.

It is speculated that asteroids larger than 5 km (which are big enough to cause long lasting, planetary effects) hit the Earth every 10 million years or so, while smaller ones (1 to 5) hit every 1 to 9 million of years. We all concur I guess that for our actual civilizations those figures are irrelevant, but they are not so of course on an evolutionary scale. As far as we know, anyways, none of such is in an orbit that will possibly cause it to hit the Earth is a relatively short period, none the less making any real prevision on a wider scale is impossible, because the variables are simply too much to calculate. Besides, as the recent passage of Oumuamua demonstrated, there are completely unpredictable dangers that we have very little chance to identify, lest defend from (this interstellar object, meaning coming from the space out of our solar system, was discovered when it was already at about 33 million km from Earth and already heading away from the Sun). Those interstellar asteroids are of the worst kind so to say, since they do not follow an orbit but they are actually only transiting in our system and therefore can come from and move to any possible direction.

A similar case is represented by the Oort cloud objects. While the Cloud in itself is a speculation, it has solid scientific base, connected with Long period and Halley's type comets. These objects are even less predictable, since the time scale is on the order of millions of years and the causing events are still to be identified (they have been speculated though, main candidates are either the gravitational effects of the Galactic tide, or, more probably those of passing by nearby stars or even molecular clouds.


Above is a gif of nearby solar systems, 3D glasses should be used to properly see it.

Quoting wikipedia

Besides the galactic tide, the main trigger for sending comets into the inner Solar System is thought to be interaction between the Sun's Oort cloud and the gravitational fields of nearby stars[5] or giant molecular clouds.[44] The orbit of the Sun through the plane of the Milky Way sometimes brings it in relatively close proximity to other stellar systems. For example, it is hypothesized that 70 thousand years ago, perhaps Scholz's Star passed through the outer Oort cloud (although its low mass and high relative velocity limited its effect).[50] During the next 10 million years the known star with the greatest possibility of perturbing the Oort cloud is Gliese 710.[51] This process could also scatter Oort cloud objects out of the ecliptic plane, potentially also explaining its spherical distribution.[51][52]

On a more fictional side, similar hypothesis have been made about the Nemesis star or the infamous Planet X.

However, whatever the reason, those are probably the most dangerous objects that could hit the Earth, the more if the theory that sees them coming in swarms rather than singularly is correct.

We really are surrounded, literally, by plenty of potential civilization destroyers and while I'm happy to see that small steps are taken to begin with, I remain that we are very far, thousands of years far, from being able to effectively protect ourselves from such dangers.

[alhoon]

I am mostly concerned about future NASA missions of similar venue.
For example, the "Future Asteroid Redirection Test" or the "Fatal Asteroid Redirection Test". The substance of said missions smells a bit funny.

[PointOfViewGun]

We are getting better at this. Getting faster. Getting more capable. Its a must for our planet to monitor our surroundings and come up with ways to respond to any threats. I don't think we are thousands of years away from this. I believe we'll see much better results within a hundred years. With quantum computing around the corner we will see how it will play out much better.

[alhoon]

Hundreds of years? Try 20 years.

[Muizer]

will probably be turned into a weapon against fellow earthlings rather than a tool to defend the planet.

[Cyclops]

will probably be turned into a weapon against fellow earthlings rather than a tool to defend the planet.

I guess there's been a rash of weapons demonstrations recently, so this could be the US flexing with a nice little twist "iTs NoT a WeApOn SyStEm...but we will drop 54509 YORP on Beijing if we want to UwU".

[PointOfViewGun]

The day has passed and the mission's most crucial moment was successfully observed. Now they'll keep on observing to see if the mission had any effect.

DART Team Celebrates Successful Collision

The investigation team will now observe Dimorphos using ground-based telescopes to confirm that DART’s impact altered the asteroid’s orbit around Didymos. Researchers expect the impact to shorten Dimorphos’ orbit by about 1%, or roughly 10 minutes; precisely measuring how much the asteroid was deflected is one of the primary purposes of the full-scale test.

[conon394]

That something is better than nothing. Such a mission has indeed some scientific values, but IMO this is more propaganda than anything else. I really doubt we have the means to really affect anything but the smallest asteroids.

Proof of concept is poof of concept. And real data is real data. It is not like this was a hugely expensive outing. I rather hope this is the first of many runs at different asteroids all with build quick and fast and accept failure to both get more data but also measure how fast seat of pants mission could be conjured up and what they can do.

[Flinn]

Proof of concept is poof of concept. And real data is real data. It is not like this was a hugely expensive outing. I rather hope this is the first of many runs at different asteroids all with build quick and fast and accept failure to both get more data but also measure how fast seat of pants mission could be conjured up and what they can do.

Nasa's DART mission hits asteroid.



Not long ago we had a discussion here about this mission, I'm still very skeptical about the effective reach of the project to be honest. Sure, we hit an asteroid, but that's not a great news either, since Rosetta and Philae already managed something similar over 6 years ago. As far as I understood, even if they are already checking about the effectiveness of the impact using telescopes from Earth and orbit, the real extent of the success will only be validated with the Hera Mission, in four years from today.

To me, there's way too much enthusiasm about this whole project, and my reason is simple: awareness of the threat, coupled by actual effectiveness of the method. As far as our knowledge goes, there are two kind of threats we have to look upon: smaller, closer asteroid that can hit with almost zero forewarning and cause local wreckage, and very large comets (I mean, VERY large, in the order of tens or hundreds of kilometers, Hale-Bopp was 60 km wide, just saying), that can potentially cause a mass extinction event. Everything in between is being mapped already, and none of them really represents a threat in any foreseeable short term.

So, from one side, we have smaller objects with which this technique could be effective, but that we can't prevent at all, from the other we have very large objects that we will be aware of months (possibly even a year) in advance as they approach the inner solar system from the Oort cloud, but that, looking at their possible sizes, would be very much invulnerable to this technique.

As I said already, we are hundreds of years far from when we will be effectively able to defend ourselves from this kind of threats.

[PointOfViewGun]

What creates enthusiasm is the new mentality rather than the effects of such a small impact. We are seeing people actually spending time to develop technologies and procedures to target a very specific problem. It's not an afterthought of a different kind of mission.

I have a question for you, Flinn. Can you guarantee that a random event at our asteroid belt will not cause one to be ejected out of the belt and onto our planet?

[Flinn]

I have a question for you, Flinn. Can you guarantee that a random event at our asteroid belt will not cause one to be ejected out of the belt and onto our planet?

I wish I could, but of course I cannot

But that's very unlikely to happen, that would need the interference of one or more external objects, a rouge asteroid like Omuamua or a large comet coming from the Oort cloud. I think it is proper now to clarify what the asteroids belt is: it's not a crowded place where asteroids crush one on another and are sent around the space in chaotic orbits, it is indeed a very quite place, that very seldom (if at all over the span of few million years) interacts with the rest of the Solar system. It might have certainly be different in the early times, but it is not so. It is a very scarcely populated area of the space (it has been calculated that collisions involving large asteroids happens once every 10 million years). So yes, it is theoretically possible that a medium sized asteroid (circa 500 m) could be involved into a causal collision and hence change its orbit, but then again we have to be incredibly unlucky that of all the possible orbits (billions, literally) it will end up moving into one aimed directly at Earth*

That being said, this whole discussion doesn't change the fact that the most dangerous objects, on human scale, are the smaller ones (between 50 and 200 m probably) which are very hard to be spotted: remember, they do not emit any form of electromagnetic energy, and can only reflect Sun's light (and that is also affected by their albedo, actually most of asteroids have a dark surface and a very low albedo), so for the most we would not simply see them until they are already burning through the atmosphere, or we will only see them a few minutes before they'll enter it. For this very reason this DART system is absolutely useless against them: if anything we would need a sort of orbital automatic defense system, science fiction as of today, hence why I say that it will take hundreds of years.

On the other side, any large life ending comet is extremely unlikely to happen in a human scale (bodies larger than 1 km should impact Earth once every 65 million years), so if that would happen when humanity is still on this planet, well then that would just be plain bad luck.

*notice: one thing that might be misleading. It is very rare for an orbiting object to impact into another at their first meeting, most of the times they get closer and closer after each passage (unless they find a sort of stability, like it happens with the Sun/Planets/Moons system, or if they are projected on an outgoing orbit) until they finally smash. Calculating the future orbits of one object is an extremely complex work, the more if there's a significant mass difference between the Earth and this body, if this body is particularly small, and if other quite larger bodies (the Sun, Jupiter) are involved in the orbital dance. Multiply it for the (literally) millions of medium objects orbiting the Earth in a somewhat "stable" orbit, and you'll get the picture: it is highly possible that even objects that we know of (like those monitored in the NEO project) will surprise us and that we will have very little time (days probably) to react to a sudden threat coming from one of those.

Believe me, our best "defense" against such threats it's the time, we are simply too insignificant on the astronomic scale to be worried about medium or large bodies hitting the Earth. We could do more to defend against small ones, probably, but the DART mission does not really aim at them.

[PointOfViewGun]

Are we able to track the objects in the asteroid belt completely? Not really. Asteroid could be ejected out of the belt not just due to factors that you name but the very same asteroids that are too small for us to track at this moment. Just like we are testing to see if we can nudge them away, small asteroid that we don't know where they are can nudge larger asteroids towards us or towards other asteroids creating threat creator collisions.

[Flinn]

Yes, but as I have said above, that is extremely unlikely to happen, even less in the human scale of time.

And again, it does not change the fact that the actual Dart system is absolutely useless against the most likely threat, or the smallest asteroids that we can't even identify with the actual means.

[PointOfViewGun]

Yes, but as I have said above, that is extremely unlikely to happen, even less in the human scale of time.
And again, it does not change the fact that the actual Dart system is absolutely useless against the most likely threat, or the smallest asteroids that we can't even identify with the actual means.

Testing human sized rockets a century ago was likely useless in our mission to get to the moon but nonetheless it was a stepping stone. With your approach anything and everything is useless.

[Flinn]

Testing human sized rockets a century ago was likely useless in our mission to get to the moon but nonetheless it was a stepping stone. With your approach anything and everything is useless.

Testing them as weapons, eh?

And once again, there is no stepping stone in the DART mission. We have already proven ourselves capable of approaching and "hitting" an orbiting body (whether large as a planet or small as an asteroid) again and again (actually even softly landing on them, which is way more complex than just hit them). The whole DART mission is just like "we don't know how to face this threat, so let's just try something spectacular". Recognizing that we don't have any real mean to defend ourselves rather than just shooting in the dark, would be the first step towards developing an efficient defensive system.

I guess I can only be proven right when a 100 m or so completely undetected asteroid will hit some populated area killing millions, but honestly I'm ok with being proven wrong, if this is the price to pay.

[PointOfViewGun]

Testing them as weapons, eh?

And once again, there is no stepping stone in the DART mission. We have already proven ourselves capable of approaching and "hitting" an orbiting body (whether large as a planet or small as an asteroid) again and again (actually even softly landing on them, which is way more complex than just hit them). The whole DART mission is just like "we don't know how to face this threat, so let's just try something spectacular". Recognizing that we don't have any real mean to defend ourselves rather than just shooting in the dark, would be the first step towards developing an efficient defensive system.

I guess I can only be proven right when a 100 m or so completely undetected asteroid will hit some populated area killing millions, but honestly I'm ok with being proven wrong, if this is the price to pay.

Is there any basis for this irrational simplicity directed at the DART mission? The approach you use here can be used for anything. Your premise that we can not detect asteroids that are between 50 to 200 meters has no basis for sure. NASA has already been tasked by the Congress to detect any near-Earth asteroid with a size of 140 meters or larger. We have the capability to detect smaller ones as well.