Solar Orbiter first images revealed | Hacker News Reader

Solar Orbiter first images revealed

esa.int

192 pointsmauliknshah40 comments

Many years ago I experienced a VR tour of the solar system on Oculus. I never fully comprehended just how big the sun was until going on that tour. Something about being able to float around in space, and see the planets stacked next to the sun going off into the horizon and looking up and down and all around at the sun, just a really cool VR exclusive experience.

Fascinated to hear what they learn from this orbiter. We're currently in the deepest solar minimum of the space age, so I wonder if they'll discover anything related to the mechanisms that drive them.

I "hacked" NASA (I used wget/curl to download the publicly available images) to get the specific shots (wavelength/resolution) from SOHO to get an entire 11 day's worth of a single rotation of the sun. We put that sequence into a VR setting. It was strictly for a demo/PoC of an idea we were knocking around. The idea didn't gain any traction with the producers, so it just got shelved. It was fun showing everyone how simple parsing a structured text file, passing that data to another app for downloading, renaming/sorting to proper image sequence format. Start it, (stop/start 2 or 3 times to fix typo bugs), walk away for the weekend to come back on monday to see stuff ready to go.

Many thanks to anyone at NASA/ESA/JAXA/anyone else that makes all of that data available!!

The data is public and this usage seems to be intended, not sure why you call it "hacking".

I quoted the word hack deliberately. There have been well known cases of people being brought up on charges for using elite hacking software known as curl and/or wget.

Also, it's what my co-workers called it. These are non-coder types, and can operate a computer just well enough to use the software they are trained to use. I use the Homebrew color scheme in Terminal, so green text on black background. Only hackers use Terminal anyway, so 1 + 1 = ? (you better have said 10)

Hacking has two meaning: one is to commit a computer crime, the other is to use technical knowledge to overcome a problem. This website name refers to the latter.

https://en.m.wikipedia.org/wiki/Computer_Fraud_and_Abuse_Act

I think you're talking about Titans of Space[1]. Closest thing to a Total Perspective Vortex I'd ever experienced[2].

1. http://www.titansofspacevr.com/titansofspace.html 2. https://hitchhikers.fandom.com/wiki/Total_Perspective_Vortex

What is this thing here? https://i.imgur.com/hxiwfe6.png (around 25%-25% from top left)

Looks distinctly not part of the corona, more like a pod of some sorts, and it also jitters around in the video. I'm puzzled!

Maybe damage to the instruments?

It is definitely a spacecraft side instrumentation artifact. Notice how all three of these jiggle the same? https://imgur.com/a/T7jduVG

‘"But in fact, it's a sensor defect," he said. "In future processing when we further optimize this, this will be cleaned up and interpolated from nearby pixels. But for the moment, it's still clearly visible."’

https://www.livescience.com/sun-tardigrade-solar-orbiter-ima...

Those are some amazingly beautiful images. And for some reason, I'm reminded of the comet-core ship that surfs just above the Sun's convection tops in The Killing Star, by Charles R. Pellegrino and George Zebrowski. Also the ~analogous ships mentioned in Vernor Vinge's Marooned in Realtime, and in Hannu Rajaniemi's "Flower Prince" trilogy.

I love watching video of activity on the solar surface because my brain has no intuition for the immense gravity and plasma dynamics at play. It's almost like getting a glimpse of a world with different laws of physics.

The surface gravity of the Sun is only about 27x that of Earth (due to its lower density). More, sure, but not so much that you should consider it different physics.

...of course the temperature and hydrogen composition make it pretty different :)

If I were to visit the sun I’d probably orbit it close up, rather than landing on the surface. Seems like the sensible thing to do.

Being in orbit, I would sense weightlessness while being in the presences of an enormous gravitational field. Just as in orbit around earth: gravity is still there, you just can’t feel it.

Would I notice anything different when weightlessly orbiting something 300,000x more massive than earth?

> Would I notice anything different when weightlessly orbiting something 300,000x more massive than earth?

Yes, due to tidal forces being stronger at one end of you than the other. You could use the formula given below but it looks like about a quarter of a newton.

One other thing: not sure you could "land on the surface" because it's all plasma. Flying through it might be interesting.

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

I would think orbiting near the sun still just feels like free fall (as far as gravity is concerned), but close to an extremely dense object like a black hole might have enough of a gradient to feel the "spaghettification" effect or even be ripped apart by it.

Yep, that's a word! https://en.wikipedia.org/wiki/Spaghettification

Haha these cookie popups, I don't know why I'm hesitant to take action on them. So like this site on mobile I'll read the article through half my phone screen.

Fun fact, the video changes from a direct video element to a YouTube element if you accept the cookie banner.

...which is then promptly blocked by my browser.

The video is only playable if I _don’t_ click the cookie nag.

This does not happen on my end. I wonder why? I'm in Europe and using Firefox with tracking protection, Privacy Badger and uBlock Origin (and no cookie popup killers of any kind). No sign of youtube, and the native element functions properly.

EDIT: Tried also on Chrome. Accepted only essential cookies. No youtube. (Chrome also has uBlock Origin installed, though I don't know how effective that currently is.)

That's interesting, just yesterday I considered the idea of the cost(host) to have to download an entire video up front eg. video tag vs. streaming(YouTube) I wonder if that is the rationale.

This is another reminder of just how little space exploration has happened so far... I'm kinda amazed no one's ever just thrown a probe at the sun to get as much data as possible before it burns. I get a similar feeling staring at the bare handful of images from the surface of Venus.

Flying close to the Sun is hard, both because of the thermal environment and the difficulty of achieving trajectories that get close. A mission that launched two years ago, Parker Solar Probe, is actually going to get closer. Parker and Solar Orbiter have different objectives and should complement each other well.

http://parkersolarprobe.jhuapl.edu/

Ya, at first glance it seems easier to get to the sun, but due to orbital mechanics it's actually harder than it seems.

Probes bound for deep-space destinations like Mars can piggyback off Earth’s momentum to fly faster. For a spacecraft to launch toward the sun, on the other hand, it must accelerate to nearly match the Earth’s velocity—in the opposite direction. With the planet’s motion essentially canceled out, the spacecraft can surrender to the sun’s gravity and begin to fall toward it. https://www.theatlantic.com/science/archive/2018/08/parker-s...

Notably it requires more delta-V - i.e. more fuel - to reach the Sun than it does to leave the Solar system entirely.

Interesting article thx.

I dont get why the speed up works only towards the outer solar system though. Why does it have to loose speed to control direction?

The direction is "towards" or "away" from the sun, the only way to get closer to the sun is to make your orbit smaller, the only way to do that is to slow down in your current orbit. You can't reach a lower orbit by accelerating. (I'm simplifying a bit, it's all acceleration, what matters is if it's in your orbital velocity, prograde, or against it, retrograde)

You can accelerate so slow down. The flyby of a planet creates an accelleration that, if in the correct direction, results in a slower orbital velocity in the sun's reference frame. In really simple terms, if you approach the planet from the right (in a counterclockwise solar system) you speed up, if you aim to the left you slow down. The velocity is transferred to/from the planet.

https://youtu.be/hKjcbmlAaYY

Notice how the probes orbit gets more eccentric but still smaller each time it approaches a planet on the left. The gravity assist is slowing it down, again in the solar reference frame.

Gravitational slingshots are a method were you accelerate and end up slowing down but I don't think it's fair to say that you "just accelerate to reach a lower orbit", since your acceleration ultimately ends up being either retrograde for very low fly-by orbits or on the normal/radial axis. Or possibly even prograde.

Basically, using a flyby to apply retrograde speed is not much more than accelerating prograde and then using the gravity of a planet to A) move your orbital position without a speed change and/or B) redirect your acceleration.

>You can't reach a lower orbit by accelerating

Ah thanks this made sense. I guess if I was spinning something on a string I would have to slow it down for the orbit to shrink.

It's all relative. You can use gravity assists to get closer to the sun, but there are a lot more planets above our orbit than below it (and mercury is too small to be useful). ...so timing gravity assisted deceleration orbits is not just hard, but it takes forever and the only reasonable solution is a very eccentric orbit.

Hmm so a probe can't sling-shot around another planet to do a U-turn?

It's possible, Parker Solar Probe is using Venus for gravity assists to get very close to the Sun. http://parkersolarprobe.jhuapl.edu/The-Mission/index.php

It will take 7 passes of Venus though.

The reason that PSP isn't taking these images despite going much closer is that it doesn't have a camera for imaging the Sun.

> kinda amazed no one's ever just thrown a probe at the sun [...] before it burns

The answer is somewhat simply that it burns real quick. These guys made the heat shield for this thing and have some decent insights: http://enbio.eu/solar-orbiter/

Also, it takes a heck of a lot of rocket fuel to just throw a probe at the Sun. More than to send it out of the solar system.

Kind of surprised this orbiter was not called Icarus

That name was floating around internally on the engineering teams until we'd ironed out the kinks.

Nominative determinism and all that...

"Published", not "revealed".

I'm sorry. This just annoys me so much. There's two perfectly good words that pretty much always should be used instead of "revealed": "Published", or "Announced".

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