Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Voyager 2’s Discoveries from Interstellar Space

nytimes.com

Post reply on HN
Print view View original

71–80 of 109 posts

Re: Voyager 2’s Discoveries from Interstellar Space

#71

Post by mlthoughts2018 »

kolinko wrote: post #58
mlthoughts2018 wrote: post #27

Earlier quoted context omitted.

Yeah but did they use Agile methods and have good team velocity as they burned down the backlog? If not, how can we really be sure the project was a success?

Agile shares a lot in common with practices mentioned in „Mythical man-month”, which in turn was based on the good practices from the Voyager era. Also, extreme programming was based in part on the TDD from Mercury program, iirc. Having said that - yes, cargo cult agile sucks, we all know that.

The surgical team analogy at the core of TMMM is totally incongruent with agile principles. The book espouses a ton of anti-agile (small a) ideas.

Re: Voyager 2’s Discoveries from Interstellar Space

#72

Post by macintux »

peteradio wrote: post #61
Aperocky wrote: post #57

Earlier quoted context omitted.

I personally believe that it is easier to put human/whatever consciousness in a computer than it is to achieve FTL. Not that the former is easy, but the latter is basically impossible. After the former is achieved, we can basically coast on sleep for eternities.

What would that point of that be?

Speaking as someone whose body is gradually breaking down, if I could wake up tomorrow in a computer headed for the stars, sign me up!

Re: Voyager 2’s Discoveries from Interstellar Space

#73

Post by macintux »

anthony_doan wrote: post #35
flurdy wrote: post #12

I am always baffled by the conundrum of the futility of launching a spacecraft to go far away by our own ability to invent faster engines. Say it takes 300 years to get to Alpha Centauri. If you launch it you have 150 years to invent a spacecraft that goes twice the speed of the first one. Very likely. If you launch that one it will overtake the other one. Now you have 75 years to find an even faster engine. Launch i…

You can't get faster engine without having slower one first. How do they even know what to improve upon without building it and experiment with it? Also simulation is not a replacement for real world testing. They should launch stuff into space to figure out if it works and their simulation is making the correct assumptions. Also I'd imagine these launches are sending back valuable data that they can use to make adju…

Based on what we seem to be learning about how the body responds to the hostile environment of space, it seems reasonable to think we should wait for the faster engines. Send drones if you must.

Re: Voyager 2’s Discoveries from Interstellar Space

#74

Post by pvg »

Aperocky wrote: post #55
ChuckNorris89 wrote: post #2

I'm amazed and still can't get my head around how today we can receive images and valuable data from a device which is currently lightdays away from us and was built with 60's technology & know-how and is operating well beyond it's expected lifetime. I raise my glass to the engineers who worked on this. Makes my daily programming tasks feel stupid in comparison. Edit: corrected, thanks for the numbers

Imagine the systems that they worked with. In the 1970s, dealing with primitive electronic systems, often without screen and most definitely without a full OS. Goosebumps. To imagine that the tech phenomenon that we can only regard as recent (2000-) but there are people from as far as 30 years back before that, working on things that have lasting impact to us. I recently read bwk's Unix history and memoir, it's a gre…

You're making it sound like the Voyager software and hardware was developed by poking soft clay tablets with a pointy reed. The systems had OS's, screens were surely available, ICs and high-level languages were in use. The '[computer-ish] tech phenomenon' itself is a fair bit older - 'Silicon Valley' is named after literal, not figurative silicon-based electronic components.

Re: Voyager 2’s Discoveries from Interstellar Space

#75

Post by JohnJamesRambo »

mlthoughts2018 wrote: post #27
ChuckNorris89 wrote: post #2

I'm amazed and still can't get my head around how today we can receive images and valuable data from a device which is currently lightdays away from us and was built with 60's technology & know-how and is operating well beyond it's expected lifetime. I raise my glass to the engineers who worked on this. Makes my daily programming tasks feel stupid in comparison. Edit: corrected, thanks for the numbers

Yeah but did they use Agile methods and have good team velocity as they burned down the backlog? If not, how can we really be sure the project was a success?

Check their Slack and ask.

Re: Voyager 2’s Discoveries from Interstellar Space

#76

Post by NovemberWhiskey »

outworlder wrote: post #54
flurdy wrote: post #12

I am always baffled by the conundrum of the futility of launching a spacecraft to go far away by our own ability to invent faster engines. Say it takes 300 years to get to Alpha Centauri. If you launch it you have 150 years to invent a spacecraft that goes twice the speed of the first one. Very likely. If you launch that one it will overtake the other one. Now you have 75 years to find an even faster engine. Launch i…

This is a fairly common trope in SciFi settings which have Generation Ships. Some time after the ship gets launched (centuries, even), FTL gets developed. Then they either arrive and find a civilization at their destination, or they are considered to be off-limits and not to be messed with, depending on the setting. That assumes such improvements are even possible. At least for non-magical propulsion, we don't really…

As in most cases, problems left for the reader are usually the hard ones!

The rocket equation tells us that if one somehow managed to build a spacecraft containing an infinite power source that weighed a single kilogram, and incorporated the most efficient engine designs known to us (electrostatic ion thrusters), it would still need to be fueled with a reaction mass of xenon equivalent to approximately two billion times the estimated mass of the observable universe to achieve even 10% of the speed of light.

Re: Voyager 2’s Discoveries from Interstellar Space

#77

Post by RosanaAnaDana »

iamcreasy wrote: post #65
outworlder wrote: post #46

Earlier quoted context omitted.

> Are they powered via PV Consider that light emitted from the Sun will decay with the square of the distance – as it is irradiated in all directions. To Voyager, the Sun looks like an ordinary star – although one much brighter than the others. Not much energy can be harvested there. Until recently, photovoltaics were useless as far away as Jupiter. Given the tech advancements, we can now use them there (and have). F…

> To Voyager, the Sun looks like an ordinary star – although one much brighter than the others. Not much energy can be harvested there. This blew my mind. Do you have a reference that talks more on this topic?

Inverse square law: https://en.wikipedia.org/wiki/Inverse-square_law

>(...) Intensity is inversely proportional to the square of the distance from the source of that physical quantity.

Shit gets dimmer at the square of the distance. So if at a distance of 1 a thing has a brightness of one, at a distance of 2 it has a brightness of 1/(2^2), or 1/4. At a distance of 8, you are looking at a brightness of 1/(8^2) or 1/64th.

Voyager 2 is ~122 AU distant. So the sun's apparent brightness would be 1/(122^2), or 1/14884, or 0.00067 % as bright as the sun as perceived at the earth-sun distance (ignoring the atmosphere of course).

Re: Voyager 2’s Discoveries from Interstellar Space

#78

Post by RosanaAnaDana »

Ancalagon wrote: post #3
ChuckNorris89 wrote: post #2

I'm amazed and still can't get my head around how today we can receive images and valuable data from a device which is currently lightdays away from us and was built with 60's technology & know-how and is operating well beyond it's expected lifetime. I raise my glass to the engineers who worked on this. Makes my daily programming tasks feel stupid in comparison. Edit: corrected, thanks for the numbers

Just FYI nothing man made is even close to light years away from the Earth. EDIT: I don't understand the downvotes. Isn't this just fact? EDIT 2: I see the OP changed his original comment, so I can understand the confusion. Thanks all :)

Do radio signals count as man-made?

Re: Voyager 2’s Discoveries from Interstellar Space

#79

Post by RosanaAnaDana »

adventured wrote: post #69
AcerbicZero wrote: post #47

I'm disappointed that it even as it become very obvious we were going to continue gathering useful information from Voyager 1/2 and yet no follow on missions have been launched. I suppose the idea is that there is more to be gained via specialized missions inside the solar system, compared with new long running extreme range probes, but you would think there might be some value in starting to send a chain of probes o…

New Horizons can and may do exactly that. http://pluto.jhuapl.edu/Mission/2019-Onward.php "Future New Horizons extended missions, if funded by NASA, could explore even farther out. The spacecraft is on an escape trajectory from the Sun, traveling about three astronomical units per year. Moreover, New Horizons and its payload sensors are healthy and operating perfectly. The spacecraft has enough power and fuel to oper…

Yeah but what do you even do out there with the sensor payload it has? Its imaging devices really aren't structured for deep space remote sensing. They were built to image planet and planet sized objects.

Re: Voyager 2’s Discoveries from Interstellar Space

#80

Post by azernik »

AcerbicZero wrote: post #47

I'm disappointed that it even as it become very obvious we were going to continue gathering useful information from Voyager 1/2 and yet no follow on missions have been launched. I suppose the idea is that there is more to be gained via specialized missions inside the solar system, compared with new long running extreme range probes, but you would think there might be some value in starting to send a chain of probes o…

Voyagers 1 and 2 took advantage of a fleeting phenomenon - an alignment of all the outer planets that allowed successive gravity assists, and so let us send probes out to those planets and then on to escape velocity with a very small launcher/budget. These come around every 175 years, so the next point at which solar system escape will be that easy is around 2150.

https://en.wikipedia.org/wiki/Grand_Tour_program

All the ideas thrown around for follow-on missions have relied either on very powerful boosters (on the scale of SLS), smaller probes (New Horizons, a bit over half the size of the Voyagers and on a much lower-energy trajectory, despite a more powerful launcher), or an Oberth maneuver close to the sun in a very challenging thermal and radiation environment.

Post reply on HN