New images of Jupiter • Hacker News Board

Re: New images of Jupiter

#81

Post by Ma8ee » Thu, Nov 07, 2024, 10:51 AM UTC

vasco wrote: post #79

Ma8ee wrote: post #78

Earlier quoted context omitted.

> not having these visions of grandure about us as some protectors of the universe Uh? Where did that come from? > is all rationalization on your part It's not rationalisation. But as all moral statements they are subjective, in the same way as the fact that you don't want your spouse or kids to die doesn't rest on some objective hard facts about the universe. And meaning can't exist without creatures like us, so we…

> Uh? Where did that come from? You wrote you wanted more people to care for it, and at the end of your comment reveal that in fact that was the reason you got pissed off, so this question seems like an underhanded "omg I have no idea what you're talking about". Also you're utterly wrong, most times the arguments are that: climate change isn't man made, that even if it is, it isn't going to affect us, that if it'll a…

Is it the sentences "There are so preciously few places like Earth. How I wish more of us cared about it." you are referring to. In that case it should be obvious even to you that "it", referred to Earth. How did you get from that to "protectors of the universe"?

> Also you're utterly wrong, most times the arguments are that...

Oh, those show up too. But it is the people who pretend that they actually belong to the thinking crowd who comes up with the your part.

It goes like this: There's no climate change. We didn't cause it. It won't be too bad. It's too expensive to do anything about it now. The world will be fine either way, with or without us.

Re: New images of Jupiter

#82

Post by foobarbecue » Thu, Nov 07, 2024, 10:58 AM UTC

adolph wrote: post #42

KWxIUElW8Xt0tD9 wrote: post #36

Earlier quoted context omitted.

I was under the impression that we now know how to do low-fuel paths through the solar system using gravity. It's more a question of how long do you want to take to get where you're going.

Yes, this specific specific duration has to do with the choice of launch vehicle. (No shade for any particular program as all have different tradeoffs and I'm gratified to see the probe successfully on its way.) The SLS option would have entailed a direct trajectory to Jupiter taking less than three years. ... The move to Falcon Heavy saved an estimated US$2 billion in launch costs alone. NASA was not sure an SLS wou…

Wow, I had forgotten the SLS plan was that much faster.

Re: New images of Jupiter

#83

Post by wkrsz » Thu, Nov 07, 2024, 1:57 PM UTC

dr_orpheus wrote: post #51

Aachen wrote: post #47

Earlier quoted context omitted.

Makes me wonder what it costs to send a "simple" camera along. Factors that make it probably not so simple: even 200 grams of camera (and extra solar panels to supply +10W while operating) probably costs many thousands of euros in rocket fuel and emission taxes. The engineering time to properly fixate it onto the spacecraft, integrate the software, and test the whole thing cost probably a few ten thousands in salarie…

Yeah, you got a lot of it and the ripple effect of things that go out from it. In addition to the extra mass of the camera and solar arrays, there is extra mass for the harnessing to connect the camera to the computer and engineering design for that as well. Integration of anything else on the spacecraft will have to go through Failure Modes Effects and Criticality Analysis (FMECA). Basically, this gets in to pretty…

TIL "babbling idiot" is a technical term https://www.wikidata.org/wiki/Q797603

> failure condition on a computer bus or network in which a malfunctioning node sends data at inappropriate times thus interfering with the communication of the working nodes

Re: New images of Jupiter

#84

Post by CableNinja » Thu, Nov 07, 2024, 3:21 PM UTC

itishappy wrote: post #74

dr_orpheus wrote: post #46

Earlier quoted context omitted.

Yep, for reference Europa Clipper is 6,065 kg [0]. It is an absolutely massive interplanetary probe. It is getting close in size to some of the largest GEO communication satellites. And to get it out to Jupiter they definitely need some of the gravity assist trajectories. On the opposite end of the spectrum, New Horizons was only 478 kg [1] and still holds the record for the fastest thing ever launched from Earth. It…

> New Horizons ... still holds the record for the fastest thing ever launched from Earth. To expand on this a bit, it's the fastest launch . The unqualified speed record goes to the Parker Solar Probe in 2018, and was previous held by Helios B way back in 1976. The distinction here is that New Horizons has spent it's life traveling away from the Sun, and it costs energy and thus speed to do so. Meanwhile, solar probe…

And parker is about to break its own record soon! Its currently about to (or has just) pass venus one last time before swinging by the sun once more, so close that it will be able to fly through the plasma loops.

Re: New images of Jupiter

#85

Post by CableNinja » Thu, Nov 07, 2024, 3:28 PM UTC

KWxIUElW8Xt0tD9 wrote: post #36

CableNinja wrote: post #32

Earlier quoted context omitted.

Pretty difficult. Jupiters sphere of influence is full of radiation, meaning the sat needs a lot of shielding which makes it very heavy. Additionally, you need a lot of thrust to not only get to Jupiter, but to be able to get into a geosync orbit around a planet other than earth, so youre gonna need a lot of fuel. And finally, time... Europa Clipper just left earth, it will be 8 years before it arrives at jupiter. Th…

I was under the impression that we now know how to do low-fuel paths through the solar system using gravity. It's more a question of how long do you want to take to get where you're going.

Oh absolutely. Most launch providers have wild algorithms that allow you to simulate every possible launch option. From the wind on earth at launch, to predicted solar activity, and of course planetary location, etc. All of this gives the ability to get the most efficient path to the target, and select other options based on the trade offs provided.

Fun side fact, solar flares and solar wind have to be taken into account during satellite orbit calculations. During one of the large flares earlier this year, the solar pressure pushed many satellites at least a few km off their orbits. Sats facing the sun lost altitude from the increased drag pressure