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Hayabusa 2 on its way back to earth


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  • 2 weeks later...

This video is apparently at ~5X real speed, though the framerate is also apparently variable. Amazing, particularly the swirling debris. @IonStorm do you think the OSIRIS-REx sample collection will be similar?

 

 

Edited by tater
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17 minutes ago, tater said:

This video is apparently at ~5X real speed, though the framerate is also apparently variable. Amazing, particularly the swirling debris. @IonStorm do you think the OSIRIS-REx sample collection will be similar?

 

 

Possibly more so.  The debris looks to be cause by their back-away thrusters.  OSIRIS-REx will also have the pneumatic sampling event.  There is a meeting between Hayabusa2 and OSIRIS-REx members next month to ask questions.  As you can imagine, we are very interested in the details of the burn.

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True, I hadn't considered that. The ejecta from the burn could likely approach the exhaust velocity of the thruster, which is possibly concerning for delicate spacecraft. I know that Phil Metzger has done a lot of work on lander exhaust/surface interactions using simulants, I tend to think of larger landers on the Moon, when smaller bodies might even be more important to look at from this standpoint given their composition.

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11 hours ago, tater said:

True, I hadn't considered that. The ejecta from the burn could likely approach the exhaust velocity of the thruster, which is possibly concerning for delicate spacecraft. I know that Phil Metzger has done a lot of work on lander exhaust/surface interactions using simulants, I tend to think of larger landers on the Moon, when smaller bodies might even be more important to look at from this standpoint given their composition.

An astute observation.  He (e.g. https://www.asteroidmission.org/team/team-list/?search=Metzger) and others were brought in to the mission during development in 2013*.  They did extensive modeling and testing (e.g. https://dslauretta.com/2014/02/05/riding-the-vomit-comet/) to be sure that the backscatter of regolith from TAG and thrusters in a Bennu environment would not damage the spacecraft (especially guidance, navigation, and control) based on our backaway speed and geometry (this is one of the reasons our solar arrays gimbal into a Y during TAG).  We have assumed that OSIRIS-REx instruments could become covered in dust, and thus are not required after sampling.  But the Hayabsa2 images suggest that their optics are intact.

*This is an example of why it takes so long to design a spacecraft to visit a novel environment.

 

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44 minutes ago, IonStorm said:

*This is an example of why it takes so long to design a spacecraft to visit a novel environment.

Very, very cool, indeed.

What do you think of the HP3 instrument on Insight (specifically the drill)? It seems like using a mass to pound the thing in might be troublesome if it cannot reel the probe back in (to try an alternate spot), and a rock under the surface dust seems... a very, very likely problem to face.

(I'll understand if you choose not to comment on another team's instrument choices)

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2 minutes ago, tater said:

What do you think of the HP3 instrument on Insight (specifically the drill)?

I'm not versed in InSight (beyond it and OSIRIS-REx sharing a highbay for a while) and what I read on public outlets.  However, I expect similar rigor and review progress to have been performed by the engineers and the standing review board (as a Discovery class instead of New Frontiers class mission, there is a different risk tolerance).

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I assumed they must have a Plan B (and likely C, D, etc). I was just sad to see they hit a rock after just ~15cm.

Probes don't get the public attention that human spaceflight does (which I get), but this kind of work is really where the RoI for spaceflight is, and it's really exciting to watch in real time (well, for some of us, anyway).

Here's a smoother version of the video:

 

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  • 4 weeks later...

It's almost time to bomb Ryugu!

http://www.planetary.org/blogs/jason-davis/what-to-expect-hayabusa2-sci.html

Quote

If you enjoyed the drama of Hayabusa2's sample collection touchdown, get ready for an even bigger fireworks display. The spacecraft is about to deploy an explosives-filled box that will detonate in space, fire a copper plate into Ryugu, and create a crater up to 10 meters wide. The moment of crater generation is set for 5 April at 02:36 UTC. Here's what to expect.

20190329_sci-artwork_f840.jpg

TL;DR: They're going to drop off an Explosively Forged Projectile (EFP) warhead and essentially a webcam to watch the excitement without risking Hayabusa 2. They'll come back to the impact point in a couple weeks to survey, and then they'll decide if they want to risk a landing at the new crater to pick up more samples. Second collection wouldn't be until June at the earliest.

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15 minutes ago, MaverickSawyer said:

Ordinance should have been dropped and fired by now.

Curse lightspeed lag.

Impressed they did set the warhead on timer and automated the redraw. 
Now if hayabusa went down just after release it would be bad :)

We will not know if this succeeded or not for some time.  

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