Author Topic: Missions to the Ice Giants Uranus and Neptune  (Read 342269 times)

Offline as58

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #740 on: 08/14/2018 05:51 pm »
so when do we say "we have tried enough"  we do a sample return from Mars...it is deader than a knob (which it will be) how much more should we try instead of say mapping the water on the moon?

Why is mapping water on the Moon scientifically so very interesting?

Offline Kansan52

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #741 on: 08/14/2018 06:23 pm »
My viewpoint is different. Water on the Moon is interesting because before, we didn't think there was any. So theories have changed and will change as we learn.

Additionally, this is an either/or that budgets create. Both would be good, if we could afford both.

Offline Blackstar

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #742 on: 08/14/2018 07:02 pm »
a  bit imprecise but I stand by my words (long day :)

3.  Scientist prioritize based on science priorities not what is a good for space and national policy as a while

while they may like a few grams of Mars rock, as I pointed out that one sample and return will be the end of it..and its less important nationally then finding and mapping the water on the moon

2.  well lets see.  if the science people had to chose between say an Europa lander or a mars sample return...it would be interesting to watch teh food fight

It's pretty clear that you have not actually read the decadal survey. Maybe you should do so before writing more opinions about it.

Offline Blackstar

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #743 on: 08/14/2018 07:08 pm »
The midterm review recommended that changes in priorities should be vetted by the Space Studies Board's Committee on Astrobiology and Planetary Science (CAPS) and allow for input from the community as soon as possible. It would take some minimum amount of time to do this, but I can't tell you exactly how much. Perhaps a couple of years after a significant discovery is made, which is probably adequate (unless Hubble sees a Crystalline Entity or something).

CAPS can be asked to produce a letter report and produce that report within a matter of months. How long it would take NASA to decide to go to CAPS is an open question.

The actual recommendation in the midterm states:

"Recommendation: If scientific discoveries or external factors compel NASA to reassess decadal
survey priorities, such as the list of New Frontiers missions, NASA should vet these changes via
CAPS, and allow for input from the community via assessment and analysis groups as time permits."

Now if the decadal survey priority that NASA wants to "reassess" is sufficiently big--like choosing a different large flagship mission than what is in the decadal survey--CAPS is probably not the method for doing that and you'd be better off with an ad hoc study. That takes longer. But if you need to have a lot of input and deliberation, then you need more time.

Also, CAPS can only produce a report with findings, not recommendations. If you want recommendations from an Academies report, you need a dedicated study.

Offline Star One

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #744 on: 08/14/2018 07:49 pm »
Thanks I hadn’t thought of it that way to be honest. But do you see areas for reform though in the decadal system?

I think that improvements can be made. The midterm review recommended that changes in priorities should be vetted by the Space Studies Board's Committee on Astrobiology and Planetary Science (CAPS) and allow for input from the community as soon as possible. It would take some minimum amount of time to do this, but I can't tell you exactly how much. Perhaps a couple of years after a significant discovery is made, which is probably adequate (unless Hubble sees a Crystalline Entity or something).

All sounds very sensible. Let’s hope it happens.

Offline Sesquipedalian

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #745 on: 08/26/2018 09:33 pm »
There was one new technology that popped up as useful for Neptune, and that was aerocapture. Doing that at Neptune is uniquely different than doing it at other planets, and we haven't done it at other planets yet anyway.

I think that one other area that would be challenging would be a Triton lander. That would require some autonomous capability that we haven't really demonstrated. Probably not all that difficult, but harder and it would have to be proven out. As much as I think a Triton lander (or rover?) would be cool, I don't see it happening. The cost and complexity is rather high.

How applicable would the technology advancements achieved by an Europa lander be to Triton?

Offline redliox

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #746 on: 08/27/2018 02:03 am »
There was one new technology that popped up as useful for Neptune, and that was aerocapture. Doing that at Neptune is uniquely different than doing it at other planets, and we haven't done it at other planets yet anyway.

I think that one other area that would be challenging would be a Triton lander. That would require some autonomous capability that we haven't really demonstrated. Probably not all that difficult, but harder and it would have to be proven out. As much as I think a Triton lander (or rover?) would be cool, I don't see it happening. The cost and complexity is rather high.

How applicable would the technology advancements achieved by an Europa lander be to Triton?

For the lander itself, reasonably so.  If you can land on Europa you could land on Triton.  Gravity assists from Triton could help somewhat like the Galileans would at Jupiter (to a lesser effect).  Slightly colder environment. The critical difference is how you get it into orbit around Neptune and shed the massive amount of velocity that a Jupiter/Europa mission doesn't have.  Basically more fuel is needed along with better tricks; it's the prework before descending into the light gravity of Triton itself that's the challenge.

Blackstar could better elaborate on these issues, although comparing Europa to Triton isn't totally dissimilar in principle.
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Offline Blackstar

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #747 on: 08/27/2018 04:23 am »
There was one new technology that popped up as useful for Neptune, and that was aerocapture. Doing that at Neptune is uniquely different than doing it at other planets, and we haven't done it at other planets yet anyway.

I think that one other area that would be challenging would be a Triton lander. That would require some autonomous capability that we haven't really demonstrated. Probably not all that difficult, but harder and it would have to be proven out. As much as I think a Triton lander (or rover?) would be cool, I don't see it happening. The cost and complexity is rather high.

How applicable would the technology advancements achieved by an Europa lander be to Triton?

For the lander itself, reasonably so.  If you can land on Europa you could land on Triton.  Gravity assists from Triton could help somewhat like the Galileans would at Jupiter (to a lesser effect).  Slightly colder environment. The critical difference is how you get it into orbit around Neptune and shed the massive amount of velocity that a Jupiter/Europa mission doesn't have.  Basically more fuel is needed along with better tricks; it's the prework before descending into the light gravity of Triton itself that's the challenge.

Blackstar could better elaborate on these issues, although comparing Europa to Triton isn't totally dissimilar in principle.

Triton doesn't have the horrible radiation that Europa does. That makes sending a spacecraft there significantly easier.

Offline redliox

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #748 on: 08/27/2018 05:01 am »
Triton doesn't have the horrible radiation that Europa does. That makes sending a spacecraft there significantly easier.

Quite correct, although the velocity problem equates to fuel loads heavier than rad shielding.  The Europa Lander is a heavy concept, physically, because it has to have a relay orbiter and large propulsion systems.  A Triton lander, excluding equivalent systems, could be a clone with lesser rad shields but it would need more robust propulsion.  For a plant analogy: same seed, tougher nut around it.
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Offline Dao Angkan

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #749 on: 08/27/2018 07:50 am »
Another difference is that Triton also has a bit of an atmosphere (~2Pa), whilst Europa's exosphere is insignificant (~0.1 μPa).
« Last Edit: 08/27/2018 07:57 am by Dao Angkan »

Offline Star One

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Missions to the Ice Giants Uranus and Neptune
« Reply #750 on: 08/27/2018 08:28 am »
I’d rather study Pluto instead as it is a truly untouched Kuiper Belt Object unlike Triton where processes are no doubt influenced by Neptune as has its evolution. What happens on Pluto is driven by itself not the fact of it being in orbit of an ice giant.

Surely Pluto doing what it does without an external influence is arguably more scientifically significant than an object with an external influence?

Which as far as these two targets are concerned is another plus point for the study of Uranus over Neptune. Uranus has more scientific oddities, is comparatively easier to get to and if you want to study a KBO go to Pluto.
« Last Edit: 08/27/2018 08:36 am by Star One »

Offline redliox

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #751 on: 08/27/2018 12:09 pm »
I’d rather study Pluto instead as it is a truly untouched Kuiper Belt Object unlike Triton where processes are no doubt influenced by Neptune as has its evolution. What happens on Pluto is driven by itself not the fact of it being in orbit of an ice giant.

Surely Pluto doing what it does without an external influence is arguably more scientifically significant than an object with an external influence?

Which as far as these two targets are concerned is another plus point for the study of Uranus over Neptune. Uranus has more scientific oddities, is comparatively easier to get to and if you want to study a KBO go to Pluto.

It isn't exactly untouched.  Pluto's heart, Tombaugh Regio, is essentially a huge melted impact crater.  Not to mention Pluto had its own interactions with Charon.  Coupled with Pluto's minimal craters that small planet's been active for its own reasons too.  Triton and Pluto, if not brother worlds, have a definite half-brother vibe to them.

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Offline Blackstar

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #752 on: 08/27/2018 03:39 pm »
The Europa Lander is a heavy concept, physically, because it has to have a relay orbiter and large propulsion systems.  A Triton lander, excluding equivalent systems, could be a clone with lesser rad shields but it would need more robust propulsion.  For a plant analogy: same seed, tougher nut around it.

The latest iteration of Europa lander eliminates the relay orbiter. Other things you note are correct.

But a Triton lander is only going to travel with a dedicated Neptune mission (and it would compete with an atmosphere probe as a secondary payload, and I suspect that the atmosphere probe wins out). The Europa lander mission is currently being proposed as a separate stand-alone mission.
« Last Edit: 08/27/2018 03:47 pm by Blackstar »

Offline Star One

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Missions to the Ice Giants Uranus and Neptune
« Reply #753 on: 08/27/2018 03:57 pm »
I’d rather study Pluto instead as it is a truly untouched Kuiper Belt Object unlike Triton where processes are no doubt influenced by Neptune as has its evolution. What happens on Pluto is driven by itself not the fact of it being in orbit of an ice giant.

Surely Pluto doing what it does without an external influence is arguably more scientifically significant than an object with an external influence?

Which as far as these two targets are concerned is another plus point for the study of Uranus over Neptune. Uranus has more scientific oddities, is comparatively easier to get to and if you want to study a KBO go to Pluto.

It isn't exactly untouched.  Pluto's heart, Tombaugh Regio, is essentially a huge melted impact crater.  Not to mention Pluto had its own interactions with Charon.  Coupled with Pluto's minimal craters that small planet's been active for its own reasons too.  Triton and Pluto, if not brother worlds, have a definite half-brother vibe to them.

But it seems as if nearly all KBOs have moons so it’s going to be hard to find one without if you’re categorising that as an influence. Many of them are also a fair fraction of the size and mass of the parent body.
« Last Edit: 08/27/2018 03:58 pm by Star One »

Offline CuddlyRocket

Re: Missions to the Ice Giants Uranus and Neptune
« Reply #754 on: 08/31/2018 07:45 am »
I’d rather study Pluto instead as it is a truly untouched Kuiper Belt Object unlike Triton where processes are no doubt influenced by Neptune as has its evolution. What happens on Pluto is driven by itself not the fact of it being in orbit of an ice giant.

Surely Pluto doing what it does without an external influence is arguably more scientifically significant than an object with an external influence?

Which as far as these two targets are concerned is another plus point for the study of Uranus over Neptune. Uranus has more scientific oddities, is comparatively easier to get to and if you want to study a KBO go to Pluto.

'Compare and contrast' is also important scientifically. We thought we had a good idea as to how planetary systems formed until we could compare and contrast the solar system with others. We've found out a lot about Pluto (and Charon) and think we understand some things and don't understand others and to move forward we need to study similar objects. So, I think if we're going to send a mission to a KBO then it should be a different one. Triton has the advantage that it's nearer and can be subsumed in a larger mission. As to the effect of the planet - that will tell us something new.

I certainly think a mission to an ice giant is warranted, but am somewhat agnostic as to whether Uranus or Neptune is preferable. However, Uranus will be quicker and likely less expensive, so I imagine it's favourite.

Offline Star One

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Missions to the Ice Giants Uranus and Neptune
« Reply #755 on: 08/31/2018 03:00 pm »
I’d rather study Pluto instead as it is a truly untouched Kuiper Belt Object unlike Triton where processes are no doubt influenced by Neptune as has its evolution. What happens on Pluto is driven by itself not the fact of it being in orbit of an ice giant.

Surely Pluto doing what it does without an external influence is arguably more scientifically significant than an object with an external influence?

Which as far as these two targets are concerned is another plus point for the study of Uranus over Neptune. Uranus has more scientific oddities, is comparatively easier to get to and if you want to study a KBO go to Pluto.

'Compare and contrast' is also important scientifically. We thought we had a good idea as to how planetary systems formed until we could compare and contrast the solar system with others. We've found out a lot about Pluto (and Charon) and think we understand some things and don't understand others and to move forward we need to study similar objects. So, I think if we're going to send a mission to a KBO then it should be a different one. Triton has the advantage that it's nearer and can be subsumed in a larger mission. As to the effect of the planet - that will tell us something new.

I certainly think a mission to an ice giant is warranted, but am somewhat agnostic as to whether Uranus or Neptune is preferable. However, Uranus will be quicker and likely less expensive, so I imagine it's favourite.

Isn’t your last sentence likely to be the deciding factors at the end of the day, over and above anything else.
« Last Edit: 08/31/2018 03:00 pm by Star One »

Offline Blackstar

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #756 on: 09/04/2018 03:12 am »
I stumbled across this site for a company that prints on metal. They have some neat ones of the planets and moons:

https://displate.com/taenaron/a-portrait-of-the-solar-system

I have not ordered from them, so I don't know the quality. But some of them are quite striking.

Offline redliox

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #757 on: 09/04/2018 03:55 am »
I stumbled across this site for a company that prints on metal. They have some neat ones of the planets and moons:

https://displate.com/taenaron/a-portrait-of-the-solar-system

I have not ordered from them, so I don't know the quality. But some of them are quite striking.

Link didn't work but man those portraits are beautiful.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline Blackstar

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #758 on: 09/04/2018 02:51 pm »
I stumbled across this site for a company that prints on metal. They have some neat ones of the planets and moons:

https://displate.com/taenaron/a-portrait-of-the-solar-system

I have not ordered from them, so I don't know the quality. But some of them are quite striking.

Link didn't work but man those portraits are beautiful.

Try:

https://displate.com/


Offline Blackstar

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Re: Missions to the Ice Giants Uranus and Neptune
« Reply #759 on: 09/12/2018 04:13 am »
From OPAG today.

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