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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

#221

Post by drjesusphd »

cgriswald wrote: post #193
dalke wrote: post #124

Earlier quoted context omitted.

There is a mission study which says it's feasible to orbit Pluto. http://www.esa.int/gsp/ACT/doc/PRO/ACT-RPR-PRO-ISTS2004-Plut... . It requires 4 RTGs, nuclear electric propulsion, and 18 years of travel time. You might be dead by the time that actually happens, so better to be killed by sorrow of only getting fly-by data than the agony of having only what Hubble and its successors can resolve.

It can't actually happen. NASA only has enough Pu-238 for three more RTGs.

Why can't they get more?

Re: New Horizons: Nasa spacecraft speeds past Pluto

#222

Post by nsxwolf »

user_0001 wrote: post #107
adventured wrote: post #44

Earlier quoted context omitted.

You already have that exact same patriotism there. Enter any thread, on any major forum online, and bring up any of the following topics: healthcare, crime rates, gun control, two party systems, standard of living, inequality, conservative religiousness. You'll be rapidly overwhelmed by bragging from Europeans, about how they're superior. You can't get away from the boastfulness out of Scandinavia, Germany, France, t…

Please link to a video showing a group of people from the UK chanting "N-H-S N-H-S" * *NHS - National Health Service for the UK

Not quite what you asked for, but "Save our NHS, it is the best!"

https://www.youtube.com/watch?v=BB5tJNJSER4

Re: New Horizons: Nasa spacecraft speeds past Pluto

#223

Post by manachar »

kartikkumar wrote: post #147
japhyr wrote: post #131

Earlier quoted context omitted.

I love HN for things like this - personal accounts of people associated with groundbreaking projects. Thanks for sharing. Most of your post is about visiting planets and exploring the solar system, but you close witha comment about disrupting science communication. What aspects of science communication are you referring to?

I realise that I made an unexplained logical leap to get to the last comment. Basically, based on my professional experience as a planetary scientist, it's my belief that the reason we don't have more satellites cruising through the Solar System is that we (and I mean scientists, engineers, administrators etc.) continue to fail in communicating their true value to the average person on the street. I think that media…

I used to think it was a failure to communicate, but I've increasingly come to the conclusion that the "average person on the street" really just doesn't care.

You can be the best speaker in the world, but you'll still only end up communicating to a small sliver of the average people.

I think changing the cultural attitudes towards science will do far more good in the long run, but it's very difficult. Ultimately, I think science isn't loved because it's slow, difficult, and filled with probablistic truth that will likely change in a few years.

This compares poorly to the easily marketable absolute truths that fill most people's days. The worst of science reporting happens when reporters try to make science fit into this mold.

Re: New Horizons: Nasa spacecraft speeds past Pluto

#224

Post by jessaustin »

ars wrote: post #212
cgriswald wrote: post #193

Earlier quoted context omitted.

It can't actually happen. NASA only has enough Pu-238 for three more RTGs.

They can use Americium-241, it's not quite as good, but it has some advantages, plus it's in much larger supply.

One can just imagine the complaints about the name of that fuel...

Re: New Horizons: Nasa spacecraft speeds past Pluto

#225

Post by calinet6 »

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.

Putting something else in orbit is the hard part.

Re: New Horizons: Nasa spacecraft speeds past Pluto

#226

Post by skykooler »

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...

Part of the reason New Horizons is going so fast is to reach Pluto in "only" ten years. A Hohmann transfer (which you would need to make a ballistic capture) would take about 124 years just to reach Pluto.

Re: New Horizons: Nasa spacecraft speeds past Pluto

#227

Post by calinet6 »

dalke wrote: post #129
tgcordell wrote: post #120

Earlier quoted context omitted.

Competition breeds innovation. Yes, we are one planet and one species, but our species is Human and we have an innate nature to compete!

Competition may breed innovation, but surely it's not the truism you suggest. Sears is an example of how the introduction of internal competition does not lead to useful innovation - http://www.forbes.com/sites/stevedenning/2013/07/16/do-inter... (It may lead to increased levels of backstabbing, but that's hardly innovative.) Humans are a social species, so also have an innate nature to cooperate. Also, the concept o…

I think of this like local vs. global maxima. Competition is one local maxima, but personally I believe cooperative systems are the global maxima. However, cooperation is more complex, more difficult, and perhaps contrary to human nature. Difficult, but not impossible.

Re: New Horizons: Nasa spacecraft speeds past Pluto

#228

Post by danbruc »

chasing wrote: post #189
chc wrote: post #183

Earlier quoted context omitted.

I think the suggestion was to send the data after impact. I guess the idea is to basically fire a shock-absorbing crate full of scientific instruments, let the impact destroy the crate, and hope the instruments survive and get to work.

Yup, that was my idea. Or to have NH itself fire off some very tiny instruments that might weight little enough to not go off like an atom bomb when hitting the ground. A GoPro, for example. (I KNOW: NOT AN ACTUAL GOPRO. A small armored camera.) Or a thermometer. The constraint there, though, might be designing equipment that is both very low mass and also capable of talking back to either Earth or the rest of NH as…

I fear that won't work. The speed relative to Pluto during closest approach was 13.78 meters every millisecond, I can't imagine that anything larger than a grain of sand will not behave like a liquid upon impact.

Re: New Horizons: Nasa spacecraft speeds past Pluto

#229

Post by calinet6 »

tlb wrote: post #152
el_duderino wrote: post #141

Earlier quoted context omitted.

The reason that the stars do not show up on the image is that the stars are so dim that the camera cannot gather enough of their light in a short exposure.

Since you can see stars near the moon, you should be able to see stars near Pluto, which is less bright. More likely, there are no stars in the (very narrow) angle of the camera.

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 approached pluto, greatly overexposing Pluto and Charon in order to see the stars around them: https://twitter.com/NewHorizonsBot/status/615264675975065600

It's difficult to imagine Pluto, being so far out, being "bright," but remember that light intensity falls off at an inverse square rate with distance. New Horizons being so close to pluto, it's actually an extremely bright object relative to the stars behind it.

In fact, NASA did a fun twitter experiment where they gave people the exact time at their location on Earth when it would appear as bright as noon on Pluto. You can see many resulting images here, illustrating how bright the Pluto surface might look were you standing on it: https://twitter.com/search?q=%23plutotime

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