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Can we send a Cassini-like mission to Uranus or Neptune?




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Voyager 2 flew past both Uranus (R) and Neptune (L), revealing the properties, colors, atmospheres, and ring systems of both worlds. We have rings, many interesting moons and atmospheric and surface phenomena we just want to wait for. NASA / Voyager 2

From where we are in the Solar System, we are looking at the distant Universe with our powerful ground-based and space-based observatories and knowledge that many of us never thought we would attain, but there is still no substitute for actually traveling to a distant place, as the missions on many planets have taught us resources that we have We've just sent a mission to Uranus and Neptune, the Voyager 2 that just flies past them. "What are our orbital outlooks? mission into these outer worlds? This is our patreon supporter Erik Jensen wants to know when he asks:

There's a window when spaceships can be sent with Jupiter for a gravitational thrust to Uranus or Neptune. What are the restrictions on use, but slow enough to get into orbit around the "ice giants"?

Let's take a look.

While a visual inspection shows a large gap between Earth size and Neptune size worlds, the reality is that you can only be about 25% larger than Earth and still be rocky. Everything bigger and you're more of a gas giant. While Jupiter and Saturn have enormous gas envelopes that cover about 85% of these planets, Neptune and Uranus are very diverse and should have large, fluid oceans under their atmosphere. Lunar and Planetary Institute

The solar system is a complicated – but luckily more regular – place. The best way to the outer solar system, that is, to any planet beyond Jupiter, is to use Jupiter itself to get there. In physics, when a small object (such as a spaceship) is flown through by a massive, stationary (such as a star or a planet), the gravitational force can greatly change its velocity, but its velocity must remain the same.

But if there is a third object that is gravitationally important, that story changes easily and in a way that is particularly relevant to reaching the outer solar system. For example, a spacecraft flying past a planet bound to the sun can gain or lose velocity by giving an impulse to the planet / solar system. The massive planet does not care, but the spacecraft can get a boost (or delay) depending on its trajectory.

A gravitational slingshot, as shown here, is how a spaceship can increase its velocity through a gravity assist. This type of maneuver is referred to as Gravitation Assistant and was essential to getting both Voyager 1 and Voyager 2 on their way out of the solar system and, more recently, bringing new horizons to fly at Pluto. Although Uranus and Neptune have spectacular long orbital periods of 84 and 165 years, respectively, the mission windows return to them every 12 years, every time Jupiter orbits.

A spaceship shot down from Earth typically flies past some of the inner planets several times in preparation for a Jupiter gravity boost. A spaceship flying past a planet can literally spin – gravitational slingshot is a word for gravity support that boosts it – to higher speeds and energies. If we want, the orientations are correct, that we could start a mission to Neptune today. Uranus, which is closer, is even easier to reach.

NASA's trajectory for the Messenger probe, which ended after a series of gravity aids in a successful, stable orbit around Mercury. The story is similar when you want to go into the outer solar system, except that you use gravity to increase your heliocentric speed instead of subtracting it. NASA / JHUAPL

A decade ago, the Argo mission was proposed to fly through Jupiter, Saturn, Neptune, and Kuiper belt objects, with a launch window from 2015 to 2019. But flyby missions are easy because of you do not have to slow down the spacecraft. It's harder to get it into orbit around a world, but it's also much more rewarding.

Instead of a single pass, an orbiter can cover an entire world, several times over long periods of time. They can observe changes in the atmosphere of a world and continuously examine them in a variety of wavelengths that are invisible to the human eye. You can find new moons, new rings and new phenomena that you never expected. You can even send a lander or probe to the planet or one of its moons. All this and more happened around Saturn with the recently completed Cassini mission.

A 2012 (L) and a 2016 (R) image of Saturn's North Pole, both taken with the Cassini wide-angle camera. The difference in color is due to changes in the chemical composition of the Saturn atmosphere, which are induced by direct photochemical changes. NASA / JPL-Caltech / Space Science Institute

Not only did Cassini get to know the physical and atmospheric properties of Saturn, though it did so spectacularly. It did not just take pictures and learn about the rings, although it did. Most amazingly, we've seen changes and transient events that we never predicted. Saturn showed seasonal changes that corresponded to chemical and color changes around his poles. A colossal storm developed on Saturn and surrounded the planet and lasted many months. It has been discovered that Saturn's rings have intense vertical structures and change over time. They are dynamic and not static and provide a laboratory to teach us about the formation of planets and moons. And with his data we solved old problems and discovered new secrets about his moons Iapetus, Titan and Enceladus.

Over a period of 8 months, the largest storm in the solar system raged and circled all gas. A huge world capable of hosting 10 to 12 Earths. NASA / JPL-Caltech / Space Science Institute

There is little doubt that we want to do the same for Uranus and Neptune. Many missions in orbit after Uranus and Neptune have been proposed and made quite wide in the mission submission process, but no plans have been made to build or fly them. NASA, ESA, JPL and the UK have all proposed Uranus orbiters who are still in the running, but nobody knows what the future holds.

So far, we have studied these worlds only remotely. But there is great hope for a future mission in many years, when the launch windows to reach both worlds will align immediately. In 2034, the conceptual ODINUS mission would simultaneously send two orbiters to both Uranus and Neptune. The mission itself would be a spectacular joint venture between NASA and ESA.

The last two (outermost) rings of Uranus as discovered by Hubble. We have discovered so much structure in the inner rings of Uranus from Voyager 2, but an orbiter could show us even more. NASA, ESA and M. Showalter (SETI Institute)

One of the Big One For the NASA survey on planetary research in 2011, a Uranus probe and an orbiter were proposed. This mission was placed third behind the Mars 2020 Rover and the Europa Clipper Orbiter. A Uranus probe-and-orbiter could start in the 2020s with a window of 21 days a year: when Earth, Jupiter and Uranus reached the optimal positions. The orbiter had three separate instruments that could be used to image and measure various properties of Uranus, its rings and its moons. Uranus and Neptune should have huge, liquid oceans under their atmosphere, and an orbiter should be able to safely discover them. The atmospheric probe would measure cloud-forming molecules, heat distribution and change in wind speed with depth.

The ODINUS mission, proposed by ESA as a joint venture with NASA, was designed to investigate both Neptune and Uranus orbiters. ODINUS Team – Mart / http://odinus.iaps.inaf.it

Under the ESA's "Cosmic Vision" program, the mission "Origins, Dynamics and Interiors of Neptune and Uranic Systems" (ODINUS ) suggested further: to extend this concept to two twin orbiters, one sending to Neptune and one to Uranus. A launch window in 2034, in which Earth, Jupiter, Uranus and Neptune align properly, could send them both at the same time.

Flyby missions are great for first encounters because you can learn so much about a world when you see them closing. They are also great because they can accomplish multiple goals, while orbiter gets stuck in any world. After all, orbiter needs to bring fuel on board to burn, slow down, and get into stable orbit, which makes a mission much more expensive. But the science you get when you stay around a planet in the long run would more than make up for it.

When you circle a world, you can see it from all sides, as well as its rings, its moons, and how they behave over time. For example, thanks to Cassini, we discovered the existence of a new ring derived from the captured asteroid Phoebe and its role in darkening only one half of the mysterious moon, Iapetus. Smithsonian Air & Space, derived from NASA / Cassini images

The current limitations of a mission like this are not technical; The technology exists to do it today. The difficulties are:

  • Political: Because NASA's budget is finite and limited and its resources must serve the entire community,
  • Physical: For even with NASA's new heavy-duty vehicle, the unarmed version of the SLS, we can only Send a limited mass to the outer solar system and
  • Practical: because at these incredible distances from the sun, solar panels do not. We need radioactive sources to power a spaceship so far away, and we may not have enough to do it.

The last, even if everything else is OK, could be the deal-breaker.

A plutonium 238 oxide pellet glows with its own heat. Py-238 is also produced as a by-product of nuclear reactions and is the radionuclide that drives deep-space vehicles from the Mars Curiosity Rover to the extremely distant Voyager spacecraft. U.S. Pat. Department of Energy

Plutonium-238 is an isotope produced during the processing of nuclear material, and most of our supplies date back to a time when we actively created and stored nuclear weapons. Its use as a thermoelectric radioisotope generator (RTG) has been spectacular for missions on the Moon, Mars, Jupiter, Saturn, Pluto, and a variety of space probes, including spacecraft Pioneer and Voyager.

But we stopped producing it in 1988, and our ability to buy it from Russia has shrunk as they have stopped producing it too. A new attempt to produce a new Pu-238 at the Oak Ridge National Laboratory has begun to produce about 2 ounces by the end of 2015. Further development there and by Ontario Power Generation could create enough to accomplish a mission by 2030

An assembly of two 591-sec images obtained through the clear filter of Voyager 2's wide-angle camera and the complete ring system of Neptune with the highest sensitivity show. Uranus and Neptune have many things in common, but a dedicated mission could also reveal unprecedented differences. NASA / JPL

The faster you move, when you hit a planet, the more fuel you have to inflict on your spaceship slow you down and get into orbit. There was no chance for a mission to Pluto; New Horizons was too small and its speed was far too big, plus Pluto's mass is quite low to make an orbital insertion. But for Neptune and Uranus, especially if we choose the right gravitational aids from Jupiter and possibly Saturn, this could be feasible. If we only choose Uranus, we could start each year in the 2020s. But if we want to go for both, what we do, 2034 is the year to go! Neptune and Uranus may look similar in terms of mass, temperature, and distance, but they can really be as different as the Earth from Venus. There is only one way to find that out. With a bit of luck and a lot of money and a lot of work we can probably find out in our lifetime.


Send your Ask Ethan questions to ghot dot com! Go to start

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Voyager 2 flew past both Uranus (R) and Neptune (L), revealing the features, colors, atmospheres, and ring systems of both worlds with rings, many interesting moons, and atmospheric and surface phenomena. we are waiting NASA / Voyager 2

From our solar system location, the view of the distant universe, with our powerful ground-based and space-based observatories, has given us many views and insights that many of us never thought we had It's done, but there is still no substitute for actually traveling to a distant place, as the missions on many planets have taught us, and despite all the resources we have devoted to planetary research, we've only ever sent one mission to Uranus and Neptune: Voyager 2 just flying past them What are our prospects for an orbiter mission in d hese outer worlds? This is what our patreon supporter Erik Jensen wants to know when he asks:

There is a window when spaceships can be sent with Jupiter for a gravitational thrust to Uranus or Neptune. What are the restrictions on use, but slow enough to get into orbit around the "ice giants"?

Let's take a look.

While a visual inspection shows a large gap between Earth size and Neptune size, worlds is the reality that you can only be about 25% larger than Earth and still be rocky. Everything bigger and you're more of a gas giant. While Jupiter and Saturn have enormous gas envelopes that cover about 85% of these planets, Neptune and Uranus are very diverse and should have large, fluid oceans under their atmospheres. Lunar and Planetary Institute

The solar system is a complicated – but fortunately, regular – place. The best way to the outer solar system, that is, to any planet beyond Jupiter, is to use Jupiter itself to get there. In physics, when a small object (such as a spaceship) is flown through by a massive, stationary (such as a star or a planet), the gravitational force can greatly change its velocity, but its velocity must remain the same.

But if there is a third object that is gravitationally important, that story changes easily and in a way that is particularly relevant to reaching the outer solar system. For example, a spacecraft flying past a planet bound to the sun can gain or lose velocity by giving an impulse to the planet / solar system. The massive planet does not care, but the spacecraft can get a boost (or delay) depending on its trajectory.

A gravitational slingshot, as shown here, is how a spaceship can increase its velocity through a gravity assist. This type of maneuver is referred to as Gravitation Assistant and was essential to getting both Voyager 1 and Voyager 2 on their way out of the solar system and, more recently, bringing new horizons to fly at Pluto. Although Uranus and Neptune have spectacular long orbital periods of 84 and 165 years, respectively, the mission windows return to them every 12 years, every time Jupiter orbits.

A spaceship shot down from Earth typically flies past some of the inner planets several times in preparation for a Jupiter gravity boost. A spaceship flying past a planet can literally spin – gravitational slingshot is a word for gravity support that boosts it – to higher speeds and energies. If we want, the orientations are correct, that we could start a mission to Neptune today. Uranus is even easier to reach as it is closer.

NASA's Messenger Messenger probe, which ended after a series of gravity assists in a successful, stable orbit around Mercury. The story is similar when you want to go into the outer solar system, except that you use gravity to increase your heliocentric speed instead of subtracting it. NASA / JHUAPL

A decade ago, the Argo mission was proposed to fly through Jupiter, Saturn, Neptune, and Kuiper belt objects, with a launch window from 2015 to 2019. But flyby missions are easy because of you do not have to slow down the spacecraft. It's harder to get it into orbit around a world, but it's also much more rewarding.

Instead of a single pass, an orbiter can cover an entire world, several times over long periods of time. They can observe changes in the atmosphere of a world and continuously examine them in a variety of wavelengths that are invisible to the human eye. You can find new moons, new rings and new phenomena that you never expected. You can even send a lander or probe to the planet or one of its moons. All this and more happened around Saturn with the recently completed Cassini mission.

A 2012 (L) and a 2016 (R) image of Saturn's North Pole, both taken with the Cassini wide-angle camera. The difference in color is due to changes in the chemical composition of the Saturn atmosphere, which are induced by direct photochemical changes. NASA / JPL-Caltech / Space Science Institute

Not only did Cassini get to know the physical and atmospheric properties of Saturn, though it did so spectacularly. It did not just take pictures and learn about the rings, although it did. Most amazingly, we've seen changes and transient events that we never predicted. Saturn showed seasonal changes that corresponded to chemical and color changes around his poles. A colossal storm developed on Saturn and surrounded the planet and lasted many months. It has been discovered that Saturn's rings have intense vertical structures and change over time. They are dynamic and not static and provide a laboratory to teach us about the formation of planets and moons. And with his data we solved old problems and discovered new secrets about his moons Iapetus, Titan and Enceladus.

Over a period of 8 months, the largest storm in the solar system raged and circled all the gas. A huge world capable of hosting 10 to 12 Earths. NASA / JPL-Caltech / Space Science Institute

There is little doubt that we want to do the same for Uranus and Neptune. Many missions in orbit after Uranus and Neptune have been proposed and made quite wide in the mission submission process, but no plans have been made to build or fly them. NASA, ESA, JPL and the UK have all proposed Uranus orbiters who are still in the running, but nobody knows what the future holds.

So far, we have studied these worlds only remotely. But there is great hope for a future mission in many years, when the launch windows to reach both worlds will align immediately. In 2034, the conceptual ODINUS mission would simultaneously send two orbiters to both Uranus and Neptune. The mission itself would be a spectacular joint venture between NASA and ESA.

The last two (outermost) rings of Uranus as discovered by Hubble. We have discovered so much structure in the inner rings of Uranus from Voyager 2, but an orbiter could show us even more. NASA, ESA and M. Showalter (SETI Institute)

One of the Big One For the NASA survey on planetary research in 2011, a Uranus probe and an orbiter were proposed. This mission was placed third behind the Mars 2020 Rover and the Europa Clipper Orbiter. A Uranus probe-and-orbiter could start in the 2020s with a window of 21 days a year: when Earth, Jupiter and Uranus reached the optimal positions. The orbiter had three separate instruments that could be used to image and measure various properties of Uranus, its rings and its moons. Uranus and Neptune should have huge, liquid oceans under their atmosphere, and an orbiter should be able to safely discover them. The atmospheric probe would measure cloud-forming molecules, heat distribution and change in wind speed with depth.

The ODINUS mission, proposed by ESA as a joint venture with NASA, investigated both Neptune and Uranus orbiters. ODINUS Team – Mart / http://odinus.iaps.inaf.it

Under the ESA's "Cosmic Vision" program, the mission "Origins, Dynamics and Interiors of Neptune and Uranic Systems" (ODINUS ) suggested further: to extend this concept to two twin orbiters, one sending to Neptune and one to Uranus. A launch window in 2034, in which Earth, Jupiter, Uranus and Neptune align properly, could send them both at the same time.

Flyby missions are great for first encounters because you can learn so much about a world when you see them closing. They are also great because they can accomplish multiple goals, while orbiter gets stuck in any world. After all, orbiter needs to bring fuel on board to burn, slow down, and get into stable orbit, which makes a mission much more expensive. But the science that you get if you stay on a planet for the long term, I would say, would more than make up for that.

When you circle a world, you can see it from all sides, as well as its rings, its moons, and how they behave over time. For example, thanks to Cassini, we discovered the existence of a new ring derived from the captured asteroid Phoebe and its role in darkening only one half of the mysterious moon, Iapetus. Smithsonian Air & Space, derived from NASA / Cassini images

The current limitations of a mission like this are not technical; The technology exists to do it today. The difficulties are:

  • Political: Because NASA's budget is finite and limited and its resources must serve the entire community,
  • Physical: For even with NASA's new heavy-duty vehicle, the unarmed version of the SLS, we can only Send a limited mass to the outer solar system and
  • Practical: because at these incredible distances from the sun, solar panels do not. We need radioactive sources to power a spaceship so far away, and we may not have enough to do the job.

The last, even if everything else is OK, could be the deal-breaker.

A plutonium 238 oxide pellet glows with its own heat. Py-238 is also produced as a by-product of nuclear reactions and is the radionuclide that drives deep-space vehicles from the Mars Curiosity Rover to the extremely distant Voyager spacecraft. U.S. Pat. Department of Energy

Plutonium-238 is an isotope produced during the processing of nuclear material, and most of our supplies date back to a time when we actively created and stored nuclear weapons. Its use as a thermoelectric radioisotope generator (RTG) has been spectacular for missions on the Moon, Mars, Jupiter, Saturn, Pluto, and a variety of space probes, including spacecraft Pioneer and Voyager.

But we stopped producing it in 1988, and our ability to buy it from Russia has shrunk as they have stopped producing it too. A new attempt to produce a new Pu-238 at the Oak Ridge National Laboratory has begun to produce about 2 ounces by the end of 2015. Further development there and by Ontario Power Generation could create enough to accomplish a mission by 2030

Merging two 591-sec images obtained through the clear filter of the wide-angle camera from Voyager 2 and the complete ring system of Neptune with the highest sensitivity show. Uranus and Neptune have many things in common, but a dedicated mission could also reveal unprecedented differences. NASA / JPL

The faster you move, when you hit a planet, the more fuel you have to inflict on your spaceship slow you down and get into orbit. There was no chance for a mission to Pluto; New Horizons was too small and its speed was far too big, plus Pluto's mass is quite low to make an orbital insertion. But for Neptune and Uranus, especially if we choose the right gravitational aids from Jupiter and possibly Saturn, this could be feasible. If we only choose Uranus, we could start each year in the 2020s. But if we want to go for both, what we do, 2034 is the year to go! Neptune and Uranus may look similar in terms of mass, temperature, and distance, but they can really be as different as the Earth from Venus. There is only one way to find that out. With a bit of luck and a lot of money and a lot of work we can probably find out in our lifetime.


Send your Ask Ethan questions to god dot com! To start with!

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