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#40
by
redliox
on 05 Apr, 2014 11:46
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I heard about the Voyager Jupiter-Uranus-Probe concept. I almost wish they'd send out fly-bys again with probes; cheaper than going the complete Galileo/Cassini route. I suppose now that we have technology they want anything sent out to give more bang for the buck.
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#41
by
Blackstar
on 06 Apr, 2014 00:31
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1-I heard about the Voyager Jupiter-Uranus-Probe concept.
2-I almost wish they'd send out fly-bys again with probes; cheaper than going the complete Galileo/Cassini route. I suppose now that we have technology they want anything sent out to give more bang for the buck.
1-Posted at the beginning of the thread.
2-The instruments are better today, but the cost/science ratio for flybys is bad. For example, a flyby will only show half the planet, not the whole thing. If you're going all that way, you want to go into orbit.
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#42
by
redliox
on 06 Apr, 2014 08:32
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1-I heard about the Voyager Jupiter-Uranus-Probe concept.
2-I almost wish they'd send out fly-bys again with probes; cheaper than going the complete Galileo/Cassini route. I suppose now that we have technology they want anything sent out to give more bang for the buck.
1-Posted at the beginning of the thread.
2-The instruments are better today, but the cost/science ratio for flybys is bad. For example, a flyby will only show half the planet, not the whole thing. If you're going all that way, you want to go into orbit.
I actually heard about the Voyager-Uranus-probe idea from "Robotic Exploration of the Solar System" series well before joining L2. It was given mention in a few paragraphs as was an idea for a Pioneer-Jupiter-probe that preceded Galileo's official conception.
And exactly my point about fly-bys. Even when it comes to asteroids probes like Dawn are demonstrating how we can intensely study them via SEP. I imagine this might mean New Horizons could be the last of it's breed, or at least fly-bys are only justifiable for the
extremely distant Kuiper Belt where there's no means to enter orbit (due to velocity/propellant issues).
Is there any information on the past Neptune Orbiter concepts?
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#43
by
vjkane
on 06 Apr, 2014 20:19
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the cost/science ratio for flybys is bad. For example, a flyby will only show half the planet, not the whole thing. If you're going all that way, you want to go into orbit.
The exception might be for atmospheric probes whose value is not hugely improved by long term global imaging (approach imaging, if carried, would see the major planes spin before them). However, it has proven difficult to justify a remote sensing flyby mission for the reasons Blackstar gave.
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#44
by
Blackstar
on 06 Apr, 2014 22:32
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the cost/science ratio for flybys is bad. For example, a flyby will only show half the planet, not the whole thing. If you're going all that way, you want to go into orbit.
The exception might be for atmospheric probes whose value is not hugely improved by long term global imaging (approach imaging, if carried, would see the major planes spin before them). However, it has proven difficult to justify a remote sensing flyby mission for the reasons Blackstar gave.
And indeed, there is a Saturn probe as a possible New Frontiers mission. But that is happening after Saturn has been studied extensively by Cassini.
I'm not sure that atmosphere probes make any sense without a remote sensing mission. The orbiter is able to provide context for the data that is collected during the descent. Without that context, I'm not sure that the probe would provide very useful data.
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#45
by
vjkane
on 07 Apr, 2014 04:27
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I'm not sure that atmosphere probes make any sense without a remote sensing mission. The orbiter is able to provide context for the data that is collected during the descent. Without that context, I'm not sure that the probe would provide very useful data.
I think the science community feels that both atmospheric composition and atmospheric remote sensing studies are important. It's apparently not important that they occur simultaneously; witness Pioneer Venus (probes arrived before orbiter), the proposed Saturn probe, and Galileo (no simultaneous remote sensing with probe relay).
Years between probe and orbiter seems to be okay.
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#46
by
GClark
on 07 Apr, 2014 05:38
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...Pioneer Venus (probes arrived before orbiter)
Actually, Pioneer Venus Orbiter arrived at Venus December 4th, the probes & bus on December 9th.
Doesn't invalidate your point, just being pedantic.
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#47
by
Blackstar
on 10 Apr, 2014 15:09
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Here is the ODINUS white paper.
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#48
by
Blackstar
on 10 Apr, 2014 21:20
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#49
by
Blackstar
on 11 Apr, 2014 18:50
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And here is something on the Uranus Pathfinder mission proposal.
I need to sort these European proposals out. I think somebody told me that they had three and then two of the teams merged, but I don't know anything about the specifics. Lemme know if you know the details.
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#50
by
redliox
on 11 Apr, 2014 20:00
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Sadly although Europe made a ton of planetary proposals the only ones that will make it to the launch pad for now will be JUICE and BepiColombo. So sadly that means it will be a while before the reach out beyond Saturn, although it was great to hear they have as much interest in the Ice Giants as their American counterparts. They are definitely promising in their deep space expeditions.
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#51
by
Blackstar
on 13 Apr, 2014 01:19
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Sadly although Europe made a ton of planetary proposals the only ones that will make it to the launch pad for now will be JUICE and BepiColombo. So sadly that means it will be a while before the reach out beyond Saturn, although it was great to hear they have as much interest in the Ice Giants as their American counterparts. They are definitely promising in their deep space expeditions.
What little I understand about how ESA selects missions always makes me wonder how they ever get anything done at all.
But I consider one of the unfortunate aspects of their selection process is that they don't have separate program lines for astronomy and planetary missions. As a result, they end up competing against each other, so if astronomy wins, planetary loses, and vice versa.
The way to look at big planetary missions in the U.S. is that you have to think in multi-decade periods. The first Mercury orbiter was proposed in the mid-1970s and took three and a half decades to happen. Galileo and Magellan also took a long time. Mars Sample Return has been under discussion for many decades and is still quite a ways away (but we're getting closer). We won't see a push for an ice giants mission until at least next decade, and probably not until the 2030s at the earliest. Being optimistic, assume a new start in the mid-30s, launch in the mid-40s, arrival in the mid-50s, or three to four decades from now.
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#52
by
as58
on 13 Apr, 2014 10:40
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But I consider one of the unfortunate aspects of their selection process is that they don't have separate program lines for astronomy and planetary missions. As a result, they end up competing against each other, so if astronomy wins, planetary loses, and vice versa.
I'm not sure if separate program lines for planetary science and astrophysics would work for ESA with current funding levels. If the science budget were split between two programs, the funding level for each of them would be very low. At least large missions would be hard to develop, as there would not be room for a large enough program slice. With the current scheme, the selected missions have access to a larger annual budget.
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#53
by
Blackstar
on 13 Apr, 2014 12:50
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I'm not sure if separate program lines for planetary science and astrophysics would work for ESA with current funding levels. If the science budget were split between two programs, the funding level for each of them would be very low. At least large missions would be hard to develop, as there would not be room for a large enough program slice. With the current scheme, the selected missions have access to a larger annual budget.
That's true. I said that the situation was "unfortunate," not that it could be easily fixed.
But one alternative would be to alternate objectives during each funding opportunity, so that planetary goes once, followed by astronomy, and so on. Of course there are potential drawbacks to that as well. Right now they ostensibly select the best mission presented to them, but what do you do if during the planetary round you only get poor planetary mission proposals?
What amazes me about the ESA system is that it works at all.
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#54
by
Blackstar
on 22 Jun, 2014 21:40
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#55
by
Burninate
on 23 Jun, 2014 16:37
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http://arxiv.org/abs/1312.6554Fast E-sail Uranus entry probe mission
The solar wind electric sail is a novel propellantless space propulsion concept. According to numerical estimates, the electric sail can produce a large total impulse per propulsion system mass. Here we consider using a 0.5 N electric sail for boosting a 550 kg spacecraft to Uranus in less than 6 years. The spacecraft is a stack consisting of the electric sail module which is jettisoned at Saturn distance, a carrier module and a probe for Uranus atmospheric entry. The carrier module has a chemical propulsion ability for orbital corrections and it uses its antenna for picking up the probe's data transmission and later relaying it to Earth. The scienti c output of the mission is similar to what the Galileo Probe did at Jupiter. Measurement of the chemical and isotope composition of the Uranian atmosphere can give key constraints for di erent formation theories of the solar system. A similar method could also be applied to other giant planets and Titan by using a fleet of more or less identical electric sail equipped probes.
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#56
by
EE Scott
on 01 Jul, 2014 20:55
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http://arxiv.org/abs/1312.6554
Fast E-sail Uranus entry probe mission
The solar wind electric sail is a novel propellantless space propulsion concept. According to numerical estimates, the electric sail can produce a large total impulse per propulsion system mass. Here we consider using a 0.5 N electric sail for boosting a 550 kg spacecraft to Uranus in less than 6 years. The spacecraft is a stack consisting of the electric sail module which is jettisoned at Saturn distance, a carrier module and a probe for Uranus atmospheric entry. The carrier module has a chemical propulsion ability for orbital corrections and it uses its antenna for picking up the probe's data transmission and later relaying it to Earth. The scientic output of the mission is similar to what the Galileo Probe did at Jupiter. Measurement of the chemical and isotope composition of the Uranian atmosphere can give key constraints for dierent formation theories of the solar system. A similar method could also be applied to other giant planets and Titan by using a fleet of more or less identical electric sail equipped probes.
That is a pretty interesting idea. I'd like to see a hypothetical sketch of what it would look like. And of course a preliminary cost analysis, but I guess it's too early for that. Nonetheless, I would think this concept (fleet of low cost atmospheric icy planet probes) would be considered very promising. It gets me excited at the possibility of relatively near-term exploration of the outer planets at a reasonable cost.
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#57
by
Burninate
on 01 Jul, 2014 21:24
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http://arxiv.org/abs/1312.6554
Fast E-sail Uranus entry probe mission
The solar wind electric sail is a novel propellantless space propulsion concept. According to numerical estimates, the electric sail can produce a large total impulse per propulsion system mass. Here we consider using a 0.5 N electric sail for boosting a 550 kg spacecraft to Uranus in less than 6 years. The spacecraft is a stack consisting of the electric sail module which is jettisoned at Saturn distance, a carrier module and a probe for Uranus atmospheric entry. The carrier module has a chemical propulsion ability for orbital corrections and it uses its antenna for picking up the probe's data transmission and later relaying it to Earth. The scientic output of the mission is similar to what the Galileo Probe did at Jupiter. Measurement of the chemical and isotope composition of the Uranian atmosphere can give key constraints for dierent formation theories of the solar system. A similar method could also be applied to other giant planets and Titan by using a fleet of more or less identical electric sail equipped probes.
That is a pretty interesting idea. I'd like to see a hypothetical sketch of what it would look like. And of course a preliminary cost analysis, but I guess it's too early for that. Nonetheless, I would think this concept (fleet of low cost atmospheric icy planet probes) would be considered very promising. It gets me excited at the possibility of relatively near-term exploration of the outer planets at a reasonable cost.
It's useful enough for a one way atmospheric probe, but...
Combine it with magnetoshell aerocapture and a bit of hydrazine for maneuvering into gravity assist windows, and you can get affordable, fast *orbiter* mission profiles to the outer planets.
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#58
by
EE Scott
on 01 Jul, 2014 21:30
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Sounds good to me.
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#59
by
Star One
on 15 Nov, 2014 14:27
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The most recent Sky At Night over here in the UK was dedicated to the ice giants and a fair part of its running time was given over to a plea by various scientists for missions to them.
