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New Horizons: Nasa spacecraft speeds past Pluto

bbc.co.uk

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Re: New Horizons: Nasa spacecraft speeds past Pluto

#251

Post by kartikkumar »

mmagin wrote: post #196
grinich wrote: post #166

Earlier quoted context omitted.

A bullet travels about 1,700 MPH. New Horizons is going about 36,300 MPH. The probe weighs 480 kilograms, so it's kinetic energy is approximately 63.2 Gigajoules. For reference, this is like 15 tonnes of TNT released on impact. Hard to make something that survives those kind of conditions.

I wonder if it would be more interesting to fire a sizable dumb projectile into Pluto and then after you've past it a bit (with proper alignment of the spacecraft, sun, and pluto) observe the absorption spectrum of the gas/dust cloud produced.

That's kinda what Deep Impact did. LRO & LCROSS did something similar, but the problem is that for a larger body, you need an impactor with a fair amount of energy before you'd be able to likely generate anything that is observable. Also, there's the planetary protection issue, which makes the design of impactors A LOT more expensive.

Re: New Horizons: Nasa spacecraft speeds past Pluto

#252

Post by tyho »

chasing wrote: post #160
kartikkumar wrote: post #89

Quote from a friend of mine on the team: "After 9.5 years and 6 billion km, we made it to Pluto 72 seconds ahead of schedule." Amazing! The views of Pluto and Charon already reveal how incredibly fascinating this system is. The dichotomy of their surface colours will most definitely lead to further insight into formation processes in the Kuiper Belt. Just such a shame that we can't land this time around. With the vol…

Any actual engineer will probably find this comment painfully naive, but here we go: If it's infeasible to slow down to get into orbit or land on Pluto, what about the feasibility of designing a probe to impact Pluto at XX km/sec and survive well enough to send back data. Like, fire a (metaphorical) bullet full of scientific instruments directly into the surface of the planet. Is it simply that we have no way to buil…

I am not an engineer, but it might be easier to launch a spacecraft with an ion engine that over years manages to reduce the speed relative to Pluto to something human scale.

Re: New Horizons: Nasa spacecraft speeds past Pluto

#253

Post by kartikkumar »

eastbayjake wrote: post #209
chasing wrote: post #160

Earlier quoted context omitted.

Any actual engineer will probably find this comment painfully naive, but here we go: If it's infeasible to slow down to get into orbit or land on Pluto, what about the feasibility of designing a probe to impact Pluto at XX km/sec and survive well enough to send back data. Like, fire a (metaphorical) bullet full of scientific instruments directly into the surface of the planet. Is it simply that we have no way to buil…

A few months ago someone posted on HN about "ballistic capture" to enter a Martian orbit with far less fuel, and I've spent the last few months wondering if you could do that to mosey into a Plutonian orbit: http://www.scientificamerican.com/article/a-new-way-to-reach...

My boss co-authored that paper [1] :) Ballistic capture is interesting: makes use of fuzzy/chaotic dynamics in the 3-Body Problem. I worked on analysis of the Weak Stability Boundary, which is the mathematical set of all points in phase-space that lie at this fuzzy boundary, for my Masters thesis [2]. It has been used in a few missions, including SMART-1, Stardust, and Hiten. ESA's Bepi-Colombo mission will also be using it to ensure that there isn't a single point-of-failure to enter orbit around Mercury.

The big problem with ballistic capture is that it doesn't guarantee a more optimal solution. Transfers can take a lot longer, and in theory even require more fuel. So it's very much a case of having to perform mission analysis on a case-by-case basis.

Nevertheless, it's an interesting prospect to send unmanned missions to Mars carrying habitat elements, before a manned mission, since they can be sent well in advance. I analyzed the prospect of potentially using a cycler [3] for this in my thesis.

[1] http://arxiv.org/abs/1410.8856

[2] http://repository.tudelft.nl/view/ir/uuid%3Ae8c99c80-a25d-4c...

[3] http://courses.ae.utexas.edu/ase333t/past_projects/04spring/...

Re: New Horizons: Nasa spacecraft speeds past Pluto

#254

Post by verytrivial »

MichaelGG wrote: post #215
ceejayoz wrote: post #172

Earlier quoted context omitted.

Plus, probes that far out have worse-than-dialup transmission rates. It takes 42 minutes to return a single photo from the LORRI camera. Bursting large amounts of data out in a short period of time before impact isn't feasible. http://www.planetary.org/blogs/emily-lakdawalla/2015/0130080...

You would put something else in orbit and have high bandwidth communication to it and relay from there.

Getting something to slow down enough to orbit is still a huge change in velocity. And even if it did, exactly how much bigger a transmitter could it carry considering it has to be hurled out to Pluto. At least with direct to Earth transmissions we can aim enormous[1] dishes at the signal source.

[1] http://deepspace.jpl.nasa.gov/about/DSNComplexes/70meter/

Re: New Horizons: Nasa spacecraft speeds past Pluto

#256

Post by yellowapple »

tammer wrote: post #157
kartikkumar wrote: post #89

Quote from a friend of mine on the team: "After 9.5 years and 6 billion km, we made it to Pluto 72 seconds ahead of schedule." Amazing! The views of Pluto and Charon already reveal how incredibly fascinating this system is. The dichotomy of their surface colours will most definitely lead to further insight into formation processes in the Kuiper Belt. Just such a shame that we can't land this time around. With the vol…

Why Uranus?

Why not Uranus?

Re: New Horizons: Nasa spacecraft speeds past Pluto

#257

Post by abecedarius »

rootbear wrote: post #100
stygiansonic wrote: post #58

As a child, I loved reading about space and astronomy. I think I pretty much read every book about these topics my local town's library. (It wasn't a large {town, library}) Isaac Asimov's non-fiction books were among my favourites. I never imagined that now we'd be getting the level of detail seen in these photos of Pluto (level of detail akin to a Moon shot), which until now, only existed in my mind from various art…

Amen. I work at NASA and I'm gobsmacked at the beauty of the New Horizons imagery. I can't wait to see the good stuff. Isaac Asimov's science essay collections had a profound effect on me. I learned physics years ahead of when I would have in school by reading these essays and learning how to do calculations involving kinetic energy, mass, acceleration, etc. Even more important, those essays helped me learn how to th…

Not just essays; he wrote something like a real physics textbook at high-school level, which I learned from as a teenager. (Not in school, of course. IIRC it was more illuminating than my actual high-school physics text.) https://en.wikipedia.org/wiki/Understanding_Physics

Re: New Horizons: Nasa spacecraft speeds past Pluto

#258

Post by ringshall »

ytdht wrote: post #233
ringshall wrote: post #101

Interesting note, as of today, the US is the first country to have successful spacecraft missions visit all of the classical planets. There is one big exception, of course: the Soviet Union was the first to have a spacecraft visit Earth, with Spunink. This category is completely arbitrary, especially given that Pluto is now considered a minor planet. Still, it's an achievement of note. Mercury - 1974, Mariner 10 Venu…

do you mean Sputnik?

Yes, not sure how that typo happened. Got it right the second time, though :)

Re: New Horizons: Nasa spacecraft speeds past Pluto

#259

Post by spuz »

buyx wrote: post #143

Plutos "demotion" from being a fully-fledged planet makes me wonder if it would have been politically feasible to start the New Horizons project if the redefinition had happened a few years earlier. Still, I am pleasantly surprised by the excitement this mission is garnering.

I actually think Pluto's classification as a dwarf planet actually gives New Horizons more significance, not less. Pluto the planet was just a tiny very far away example of an object which we have already studied a great deal of. Pluto the dwarf planet instead is one of the largest and nearest example of an object we know very little and have never studied before (I.e. the kupier belt objects) and which can give us hopefully a lot more insight into how the solar system formed.

Re: New Horizons: Nasa spacecraft speeds past Pluto

#260

Post by [deleted] »

tlb wrote: post #246
calinet6 wrote: post #229

Earlier quoted context omitted.

This is exactly the reason. Properly exposed with a camera, you cannot see stars near the moon. This is exactly the same effect. There are probably not any stars of high enough magnitude to be visible on the same exposure with such a bright object. In fact, there are definitely not: otherwise, we would see them on the image. For more proof, check out some earlier navigation images taken by New Horizons as it approach…

I stand corrected.

[deleted]
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