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A dwarf planet coming within 11 AU of the sun over the next 10 years

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Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#51

Post by messe »

perihelions wrote: post #33
messe wrote: post #14

Earlier quoted context omitted.

Getting into orbit would be rather difficult, as the probe would have have to match the planets velocity at perihelion. My instinct says it’s probably just on the edge of doable (although I’m not sure on which side), but I haven’t crunched the numbers. It would almost certainly need to be launched on a Delta-IV or Falcon Heavy class vehicle. EDIT: s/perigee/perihelion. I could say periapse and be neutral, but perihel…

It's difficult to believe that ten years from now, there'd be any serious options other than Starship and its future peers. (Incidentally, the Delta IV is already at end-of-life; ULA is replacing it with Vulcan and its Blue Origin engines. The final Delta IV-H launches are planned for 2023). https://spacenews.com/ulas-delta-4-heavy-down-to-final-five-...

I more meant that it would take at least that size-class of heavy lift launch vehicle.

With Starship this would definitely be doable, and I’m really optimistic about it; I just wanted to be cautious in my predictions.

I also wouldn’t be surprised if Delta IV’s life gets extended. Vulcan is facing plenty of development delays, and Blue Origin are yet to produce anything useful.

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#52

Post by c3534l »

Meerax wrote: post #23

Is this something we could plan and manage to launch an orbiter/lander to in time? Has anyone thought about the possibility of slapping something like a telescope on that and letting it beam back data and images from veryyyyy far out eventually?

Apparently no one likes this idea. Here's mine: we nuke the planet and collect its smitherines for SCIENCE!

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#53

Post by jessriedel »

tonmoy wrote: post #38
jessriedel wrote: post #27

Earlier quoted context omitted.

If you launch your telescope on a spacecraft and get it to match speed with the dwarf planet (which is necessary for a soft landing), there's not much point in actually attaching it to the dwarf planet. That just blocks the view of half the sky. Also, there will be nothing to see out there other than the dwarf planet itself.

Is that really true? If we manage to get a spacecraft get captured by the dwarf planet's gravity and orbit it, would that not be a lot less delta-V compared to if we made the spacecraft achieve the dwarf planet's orbit around the sun just by itself?

Yes, this is an aspect of orbital mechanics that people find unintuitive before they study it. You can't be captured by a planet's gravity alone. If you come in from infinity (i.e., not already captured) you will escape to infinity (remain not captured). The basic idea can be seen from the fact that gravitational dynamics are time-reversible, so if gravity could capture you like this you could also start in orbit around a planet and spontaneously be ejected.

Now, something like this can work if you use an irreversible interaction like aerobreaking, but this dwarf planet has negligible atmosphere. You could also use the dwarf planet for a gravitational assist (basically bouncing off it like a billiard ball), but I think gravitational assists from the other planets are almost always more convenient and effective.

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#54

Post by btilly »

0-_-0 wrote: post #46
jbay808 wrote: post #36

Earlier quoted context omitted.

Could you get a nice gravity boost away from the sun by just following it for as long as possible?

I think it should provide a much stronger slingshot velocity boost than any other planet, however getting to 11AU first is not easy. https://en.wikipedia.org/wiki/Gravity_assist

For the best gravity assist you want to have a large delta V, and you want to come in on a hyperbolic orbit that causes you to turn by 90 degrees.

This object has all of the delta V that you could want, but for an object of that mass, the hyperbolic orbit would require going through the planetoid which you can't do. And if it was dense enough that you could (for example a miniature black hole), the tidal forces during the turn would be insane.

So no, this object cannot give a decent slingshot.

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#56

Post by 015a »

c3534l wrote: post #52
Meerax wrote: post #23

Is this something we could plan and manage to launch an orbiter/lander to in time? Has anyone thought about the possibility of slapping something like a telescope on that and letting it beam back data and images from veryyyyy far out eventually?

Apparently no one likes this idea. Here's mine: we nuke the planet and collect its smitherines for SCIENCE!

Let's send some boosters out there, redirect it to earth, and make a second moon. Come on people, what ever happened to doing shit cause its fuckin' rad, do you know how cool another moon would be?!

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#57

Post by tmhrtly »

jessriedel wrote: post #53
tonmoy wrote: post #38

Earlier quoted context omitted.

Is that really true? If we manage to get a spacecraft get captured by the dwarf planet's gravity and orbit it, would that not be a lot less delta-V compared to if we made the spacecraft achieve the dwarf planet's orbit around the sun just by itself?

Yes, this is an aspect of orbital mechanics that people find unintuitive before they study it. You can't be captured by a planet's gravity alone. If you come in from infinity (i.e., not already captured) you will escape to infinity (remain not captured). The basic idea can be seen from the fact that gravitational dynamics are time-reversible, so if gravity could capture you like this you could also start in orbit aro…

What if we crash landed into it? That would probably tick the irreversible box. Clearly engineering difficulties quite high though!

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#58

Post by Sharlin »

tmhrtly wrote: post #57
jessriedel wrote: post #53

Earlier quoted context omitted.

Yes, this is an aspect of orbital mechanics that people find unintuitive before they study it. You can't be captured by a planet's gravity alone. If you come in from infinity (i.e., not already captured) you will escape to infinity (remain not captured). The basic idea can be seen from the fact that gravitational dynamics are time-reversible, so if gravity could capture you like this you could also start in orbit aro…

What if we crash landed into it? That would probably tick the irreversible box. Clearly engineering difficulties quite high though!

This is often jocularly called lithobraking and is typically not advisable.

Re: A dwarf planet coming within 11 AU of the sun over the next 10 years

#59

Post by lopuhin »

mcorning wrote: post #13

For reference 1 AU (Astronomical Unit) is about 150 million km. Saturn ranges from being about 7 to 11 AU away from Earth. Voyager 1 is 152 AU away. This object is excitingly close and will be fun to study.

I don't think Saturn comes that close, should be 8 AU at best, given that perihelion is at 9 AU.
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