Comparing two proposed NASA missions to Jupiter’s moon Io

Due to NASA’s Juno mission to the Jupiter system, we’re getting our greatest appears to be like ever on the gas giant’s volcanic moon Io. Whilst Juno supplies our greatest views of the moon, it additionally deepens our present questions. Solely a devoted mission to Io can reply these questions, and there are two proposed missions.

Io is well-known as probably the most geologically lively world within the solar system, and it isn’t even shut. It has greater than 400 lively volcanoes. Io is the closest moon to Jupiter, and the planet’s highly effective gravity is essentially answerable for Io’s volcanoes.

Because the planet pulls on Io, the friction creates tidal heating within the moon’s inside. This creates magma and drives its volcanic eruptions. Sulfur compounds within the eruptions paint the moon’s floor in shades of purple, yellow, white, black, and inexperienced.

There’s by no means been a devoted mission to Io, solely missions that captured photos as they handed by, together with Galileo, Voyager 1, Cassini, New Horizons, and Juno, NASA’s present mission to Jupiter. However Io is intriguing and distinctive, and it may possibly train us loads.

Planetary scientists need to know extra concerning the moon’s geological processes. Io is taken into account a excessive warmth flux world, and scientists need to be taught extra about its tidal dissipation. Finding out Io can even inform us extra about primitive planetary our bodies that had been as soon as extra volcanic, which Earth probably was early in its historical past.

Io can even inform us extra about volcanogenic atmospheres, which may play an important position in shaping a planet’s setting. This 2020 paper attracts a hyperlink between Earth’s volcanic exercise and the Nice Oxygenation Occasion, a crucial interval when oxygen gathered in Earth’s environment. A greater understanding of the hyperlink between volcanic exercise and atmospheric evolution will assist us higher perceive exoplanets and habitability.

Scientists know that the Galilean moons trade materials with Jupiter’s environment and magnetosphere. In addition they know that materials ejected from Io’s volcanoes can attain the surfaces of the opposite moons. A few of it may be became plasma by Jupiter’s highly effective magnetosphere, forming Io’s plasma torus. They’re interested in this mass trade within the Jupiter system and the way it’s formed the moons.

These are the explanations for a devoted mission to Io.

In 2010, scientists on the College of Arizona and Johns Hopkins College’s Utilized Physics Laboratory first proposed the Io Volcano Observer (IVO) as a part of NASA’s Discovery Program. IVO was proposed as a low-cost mission to discover Jupiter’s volcanic moon. It was proposed once more in 2015 and in 2019. In 2020, IVO was chosen with two different missions for additional research however finally misplaced out to the DAVINCI+ and VERITAS missions to Venus.

Now, there’s one other proposal for the Io Volcano Observer, however this time, it is below NASA’s New Frontiers Program. The brand new proposal exhibits that the need for an Io-focused mission will not go away. As a substitute, it is gaining steam.

In a new paper nonetheless topic to look assessment, a gaggle of principally American scientists current their case for the New Frontiers IVO. It is titled “Evaluating NASA Discovery and New Frontiers Class Mission Ideas for the Io Volcano Observer (IVO)” and its accessible on the arXiv preprint server. The primary creator is Christopher Hamilton from the Lunar and Planetary Laboratory, College of Arizona.

The IVO NF would handle our scientific questions by reaching three targets, based on the authors:

• Decide how and the place tidal warmth is generated inside Io;
• Perceive how tidal warmth is transported to the floor of Io;
• Perceive how Io is evolving.

The unique IVO proposal had the spacecraft encounter Io 10 instances in 4 years after reaching the moon in 2033. It could’ve carried 5 devices, with a sixth into consideration. The IVO would’ve crossed Io from pole to pole, passing over the equator at an altitude of between 200 and 500 kilometers (124 and 310 miles.)

The closest approaches had been fastidiously designed to present the spacecraft the very best observations of the moon’s magnetic discipline, gravity discipline, and libration amplitude. The approaches additionally would’ve allowed for each sunlit and darkish views of volcanoes, permitting the spacecraft to review the composition of lava. The polar perspective would’ve offered new views of warmth emanating from the moon that had been unavailable to Galileo and unobservable from Earth.

The brand new IVO NF proposal maintains the polar orbit of the unique IVO however improves it in a number of methods. Universe At this time talked with lead creator Christopher Hamilton concerning the new proposal. His remarks have been flippantly edited for readability.

The primary change within the new proposal issues the variety of flybys, which might enhance from 10 to twenty.

“10 flybys for the unique Discovery-level IVO mission would fill vital gaps in picture protection that stay unfilled after the Voyager and Galileo period,” Hamilton stated. So why double it?

“The brand new tour not solely doubles the picture protection of Io’s floor with high-resolution imaging but additionally allows extra flybys of lively volcanoes, like Loki, Loki Patera, and Pillian Patera,” Hamilton stated. “These are extremely dynamic volcanic techniques that embody lively lava lakes and explosive eruptions—one cross over the volcanic techniques is just not sufficient to constrain their time-variability and eruption dynamics.”

Like Earth’s moon, Io is tidally locked to Jupiter, with one facet extra available for research than the Jupiter-facing facet. However Jupiter’s impact on Io is way stronger than Earth’s impact on the moon. “Nonetheless, tidal interactions between Jupiter and Io are a lot stronger, thrilling tides in strong rock with an amplitude of about 100 m (328 ft), which is taller than the Statue of Liberty!” Hamilton stated.

These tidal interactions drive Io’s highly effective volcanism. “Nonetheless, research of the previous decade have steered that this warmth has additionally melted a layer inside Io to type a subsurface ‘”‘magma ocean,'” Hamilton stated.

The unique IVO’s 10 orbits, with its magnetometer instrument, would have confirmed or excluded this speculation. The brand new proposal will carry an improved model of this instrument, and with extra orbits, it might reply questions on Io’s magma ocean.

“IVO-NF would additionally carry a fluxgate magnetometer and with the repeat passes, fastidiously timed to measure Io’s induced magnetic discipline at totally different instances in its orbit, would drastically scale back the uncertainty in estimating a possible magma ocean’s depth,” Hamilton stated.

The present uncertainty is ±10 km, however IVO NF would scale back it to ±3 km. This “would revolutionize our understanding of Io’s inside and the hyperlinks between tidal heating and volcanism,” Hamilton informed Universe At this time.

“Each IVO and IVO-NF are nice missions, however doubling the variety of flybys greater than doubles the scientific return from an Io mission!” Hamilton stated.

IVO-NF would additionally strategy Io a lot nearer than the unique IVO. The unique mission known as for an altitude of 200 and 500 kilometers (124 and 310 miles) above Io’s floor. IVO-NF would start its mission with high-altitude fly-bys, however because the mission progressed and aims had been reached, it might come a lot nearer.

“With 20 flybys, IVO-NF might be extra daring, flying nearer to Io’s floor and even flying via its volcanic plumes to find out the chemistry of its erupted merchandise in unprecedented element,” Hamilton informed Universe At this time.

Preliminary flybys can be at about 200 km, “however because the mission progresses and Baseline aims are achieved, we will decrease the altitude of later flybys over active volcanoes like Pele Patera,” Hamilton stated.

“Nonetheless, we’d picture and analyze these volcanoes first, making use of repeat protection to additional constrain the protection of the shut strategy, and take precautions like reorienting the spacecraft’s solar panels in order that they fly via the plume side-on reasonably than exposing the total cross-sectional space,” Hamilton informed Universe At this time.

“Plume flythroughs for Io would additionally open the door to different sampling alternatives for plumes on Saturn’s lively moon, Enceladus.”

“This may increasingly appear harmful, however even at altitudes of fifty km, there can be only a few particles,” Hamilton stated. However earlier than the spacecraft comes that shut, it’s going to use its Floor Mud Analyzer to grasp the hazard.

This instrument was added to the IVO-NF as a prime precedence. It can measure floor dust composition and the composition of nanograins within the volcanic plumes. Total, it would give scientists a greater understanding of Io’s dust setting and inform them if it is secure to strategy inside 50 km.

In response to Hamilton, we’re experiencing a renaissance in exploring the Jovian system.

“This is a crucial time in Planetary Exploration, and exploration of the Jupiter System is present process a renaissance, with Juno, Europa Clipper, and JUICE inspecting Jupiter, Europa, and Ganymede on the identical time,” Hamilton informed Universe At this time.

Io is a crucial a part of Jupiter’s moon system. It is on the coronary heart of the orbital resonance configuration between Io, Europa, and Ganymede, and the resonance drives geological exercise on all three moons, together with volcanism, tectonic exercise, and the formation of floor options.

“Juno has crammed some vital gaps left after the top of the Galileo mission (1995–2003), however IVO and IVO-NF can be the primary to have an instrument suite that’s optimized particularly for Io,” stated Hamilton.

To the intellectually curious, the whole lot in nature is worthy of research and deeper understanding. A rare world like Io is actually no exception, with the whole lot it has to inform us about itself, its sibling moons, and even concerning the early Earth and moon.

“Our paper makes the case that Io is a precedence goal for exploration that needs to be thought-about within the subsequent New Frontier Announcement of Alternative,” Hamilton informed Universe At this time. He acknowledges that the unique IVO mission on the Discovery stage is feasible, however the IVO New Frontiers mission would accomplish much more and would extra totally handle our excellent questions on Io.

“A bigger mission to Io by way of New Frontiers would greater than double the scientific return of the mission and would supply the very best strategy to understanding not simply Io, however the Jupiter System as a complete, and the origins of high-heat flux worlds just like the early Earth, early moon, and different terrestrial planets within the solar system and past,” Hamilton concluded.