Is Time To Go Back to Uranus and Neptune? Revisiting Ice Giants of the Solar System

We've Got To Go Back!


I look forward to all the future missions that NASA is going to be sending out in the Solar System. Here, check this out. You can use NASA’s website to show you all the future missions. Here’s everything planned for the future, here’s everything going to Mars.

Now, let’s look and see what missions are planned for the outer planets of the Solar System, especially Uranus and Neptune. Oh, that’s so sad… there’s nothing.

Uranus, seen by Voyager 2. Image credit: NASA/JPL

It’s been decades since humanity had an up close look at Uranus and Neptune. For Uranus, it was Voyager 2, which swept through the system in 1986. We got just a few tantalizing photographs of the ice giant planet and it’s moons.

Mosaic of the four highest-resolution images of Ariel taken by the Voyager 2 space probe during its 1986 flyby of Uranus. Credit: NASA/JPL

What’s that?

Oberon, as imaged by the Voyager 2 probe during its flyby on Jan. 24, 1986. Credit: NASA

What’s going on there?

Color composite of the Uranian satellite Miranda, taken by Voyager 2 on Jan. 24, 1986, from a distance of 147,000 km (91,000 mi). Credit: NASA/JPL

What are those strange features? Sorry, insufficient data.

And then Voyager 2 did the same, zipping past Neptune in 1989.

Reconstruction of Voyager 2 images showing the Great Black spot (top left), Scooter (middle), and the Small Black Spot (lower right). Credit: NASA/JPL

Check this out.

Neptune’s largest moon Triton photographed on August 25, 1989 by Voyager 2. Credit: NASA

What’s going here on Triton? Wouldn’t you like to know more? Well, too bad! You can’t it’s done, that’s all you get.

Don’t get me wrong, I’m glad we’ve studied all these other worlds. I’m glad we’ve had orbiters at Mercury, Venus, everything at Mars, Jupiter, and especially Saturn. We’ve seen Ceres and Vesta, and the Moon up close. We even got a flyby of Pluto and Charon.

It’s time to go back to Uranus and Neptune, this time to stay.

And I’m not the only one who feels this way.

Scientists at NASA recently published a report called the Ice Giant Mission Study, and it’s all about various missions that could be sent to explore Uranus, Neptune and their fascinating moons.

The team of scientists who worked on the study considered a range of potential missions to the ice giants, and in the end settled on four potential missions; three that could go to Uranus, and one headed for Neptune. Each of them would cost roughly $2 billion.

Uranus is closer, easier to get to, and the obvious first destination of a targeted mission. For Uranus, NASA considered three probes.

The first idea is a flyby mission, which will sweep past Uranus gathering as much science as it can. This is what Voyager 2 did, and more recently what NASA’s New Horizons did at Pluto. In addition, it would have a separate probe, like the Cassini and Galileo missions, that would detach and go into the atmosphere to sample the composition below the cloudtops. The mission would be heavy and require an Atlas V rocket with the same configuration that sent Curiosity to Mars. The flight time would take 10 years.

NASA’s Curiosity Mars Science Laboratory (MSL) rover blasts off for Mars atop a stunningly beautiful Atlas V rocket. Credit: Ken Kremer – kenkremer.com

The main science goal of this mission would be to study the composition of Uranus. It would make some other measurements of the system as it passed through, but it would just be a glimpse. Better than Voyager, but nothing like Cassini’s decade plus observations of Saturn.

I like where this is going, but I’m going to hold out for something better.

The next idea is an orbiter. Now we’re talking! It would have all the same instruments as the flyby and the detachable probe. But because it would be an orbiter, it would require much more propellant. It would have triple the launch mass of the flyby mission, which means a heavier Atlas V rocket. And a slightly longer flight time; 12 years instead of 10 for the flyby.

Because it would remain at Uranus for at least 3 years, it would be able to do an extensive analysis of the planet and its rings and moons. But because of the atmospheric probe, it wouldn’t have enough mass for more instruments. It would have more time at Uranus, but not a much better set of tools to study it with.

Okay, let’s keep going. The next idea is an orbiter, but without the detachable probe. Instead, it’ll have the full suite of 15 scientific instruments, to study Uranus from every angle. We’re talking visible, doppler, infrared, ultraviolet, thermal, dust, and a fancy wide angle camera to give us those sweet planetary pictures we like to see.

Study Uranus? Yes please. But while we’re at it, let’s also sent a spacecraft to Neptune.

The labeled ring arcs of Neptune as seen in newly processed data. The image spans 26 exposures combined into a equivalent 95 minute exposure, and the ring trace and an image of the occulted planet Neptune is added for reference. (Credit: M. Showalter/SETI Institute).

As part of the Ice Giants Study, the researchers looked at what kind of missions would be possible. In this case, they settled on a single recommended mission. A huge orbiter with an additional atmospheric probe. This mission would be almost twice as massive as the heaviest Uranus mission, so it would need a Delta IV Heavy rocket to even get out to Neptune.

As it approached Neptune, the mission would release an atmospheric probe to descend beneath the cloudtops and sample what’s down there. The orbiter would then spend an additional 2 years in the environment of Neptune, studying the planet and its moons and rings. It would give us a chance to see its fascinating moon Triton up close, which seems to be a captured Kuiper Belt Object.

Unfortunately there’s no perfect grand tour trajectory available to us any more, where a single spacecraft could visit all the large planets in the Solar System. Missions to Uranus and Neptune will have to be separate, however, if NASA’s Space Launch System gets going, it could carry probes for both destinations and launch them together.

The goal of these missions is the science. We want to understand the ice giants of the outer Solar System, which are quite different from both the inner terrestrial planets and the gas giants Jupiter and Saturn.

The Solar System. Credit: NASA

The gas giants are mostly hydrogen and helium, like the Sun. But the ice giants are 65% water and other ices made from methane and ammonia. But it’s not like they’re big blobs of water, or even frozen water. Because of their huge gravity, the ice giants crush this material with enormous pressure and temperature.

What happens when you crush water under this much pressure? It would all depend on the temperature and pressure. There could be different types of ice down there. At one level, it could be an electrically conductive soup of hydrogen and oxygen, and then further down, you might get crystallized oxygen with hydrogen ions running through it.

Hailstones made of diamond could form out of the carbon-rich methane and fall down through the layers of the planets, settling within a molten carbon core. What I’m saying is, it could be pretty strange down there.

We know that ice giants are common in the galaxy, in fact, they’ve made up the majority of the extrasolar planets discovered so far. By better understanding the ones we have right here in our own Solar System, we can get a sense of the distant extrasolar planets turning up. We’ll be better able to distinguish between the super earths and mini-neptunes.

Artist’s impression of the Milky Way’s 100 billion exoplanets. Credit: NASA, ESA, and M. Kornmesser (ESO)

Another big question is how these planets formed in the first place. In their current models, most planetary astronomers think these planets had very short time windows to form. They needed to have massive enough cores to scoop up all that material before the newly forming Sun’s solar wind blasted it all out into space. And yet, why are these kinds of planets so common in the Universe?

The NASA mission planners developed a total of 12 science objectives for these missions, focusing on the composition of the planets and their atmospheres. And if there’s time, they’d like to know about how heat moves around, their constellations of rings and moons. They’d especially like to investigate Neptune’s moons Triton, which looks like a captured Kuiper Belt Object, as it orbits in the reverse direction from all the other moons in the Solar System.

In terms of science, the two worlds are very similar. But because Neptune has Triton. If I had to choose, I’d go with a Neptune mission.

Neptune and its large moon Triton as seen by Voyager 2 on August 28th, 1989. (Credit: NASA).

Are you excited? I’m excited. Here’s the bad news. According to NASA, the best launch windows for these missions would be 2029 or 2034. And that’s just the launch time, the flight time is an additional decade or more on top of that. In other words, the first photos from a Uranus flyby could happen in 2039 or 2035, while orbiters could arrive at either planet in the 2040s. I’m sure my future grandchildren will enjoy watching these missions arrive.

But then, we have to keep everything in perspective. NASA’s Cassini mission was under development in the 1980s. It didn’t launch until 1997, and it didn’t get to Saturn until 2004. It’s been almost 20 years since that launch, and almost 40 years since they started working on it.

I guess we need to be more patient. I can be patient.

Schiaparelli’s One Second Of Terror

The European Space Agency (ESA) and Roscomos (the Russian federal space agency) had high hopes for the Schiaparelli lander, which crashed on the surface of Mars on October 19th. As part of the ExoMars program, its purpose was to test the technologies that will be used to deploy a rover to the Red Planet in 2020.

However, investigators are making progress towards determining what went wrong during the lander’s descent. Based on their most recent findings, they concluded that an anomaly took place with an on-board instrument that led to the lander detaching from its parachute and backshell prematurely. This ultimately caused it to land hard and be destroyed.

According to investigators, the data retrieved from the lander indicates that for the most part, Schiaparelli was functioning normally before it crashed. This included the parachute deploying once it had reached an altitude of 12 km and achieved a speed of 1730 km/h. When it reached an altitude of 7.8 km, the lander’s heatshield was released, and it radar altimeter provided accurate data to the lander’s on-board guidance, navigation and control system.

Schiaparelli lander descent sequence. Image: ESA/ATG medialab
Schiaparelli lander descent sequence. According to their investigation, the ESA has determined that an error led the parachute and backshell to be jettisoned prematurely, causing the lander to crash. Credit: ESA/ATG medialab

All of this happened according to plan and did not contribute to the fatal crash. However, an anomaly then took place with the Inertial Measurement Unit (IMU), which is there to measure the rotation rates of the vehicle. Apparently, the IMU experienced saturation shortly after the parachute was deployed, causing it to persist for one second longer than required.

This error was then fed to the navigation system, which caused it to generate an estimate altitude that was below Mars’ actual ground level. In essence, the lander thought it was closer to the ground than it actually was. As such, the the parachute and backshell of the Entry and Descent Module (EDM) were jettisoned and the braking thrusters fired prematurely – at an altitude of 3.7 km instead of 1.2 km, as planned.

This briefest of errors caused the lander to free-fall for one second longer than it was supposed to, causing it to land hard and be destroyed. The investigators have confirmed this assessment using multiple computer simulations, all of which indicate that the IMU error was responsible. However, this is still a tentative conclusion that awaits final confirmation from the agency.

Schiaparelli on Mars. Credit: ESA/ATG medialab
Artist’s impression of the Schiaparelli lander on Mars. Credit: ESA/ATG medialab

As David Parker, the ESA’s Director of Human Spaceflight and Robotic Exploration, said on on Wednesday, Nov. 23rd in a ESA press release:

“This is still a very preliminary conclusion of our technical investigations. The full picture will be provided in early 2017 by the future report of an external independent inquiry board, which is now being set up, as requested by ESA’s Director General, under the chairmanship of ESA’s Inspector General. But we will have learned much from Schiaparelli that will directly contribute to the second ExoMars mission being developed with our international partners for launch in 2020.”

In other words, this accident has not deterred the ESA and Roscosmos from pursuing the next stage in the ExoMars program – which is the deployment of the ExoMars rover in 2020. When it reaches Mars in 2021, the rover will be capable of navigating autonomously across the surface, using a on-board laboratory suite to search for signs of biological life, both past and present.

In the meantime, data retrieved from Schiaparelli’s other instruments is still being analyzed, as well as information from orbiters that observed the lander’s descent. It is hoped that this will shed further light on the accident, as well as salvage something from the mission. The Trace Gas Orbiter is also starting its first series of observations since it made its arrival in orbit on Oct. 19th, and will reach its operational orbit towards the end of 2017.

Further Reading: ESA

Feast Your Mind on This: Strange “Brain Terrain” on Mars

It doesn’t take much thought to understand why this landscape on Mars is called “brain terrain” — the swirling lobes of ice, part of a large glacial deposit in Mars’ northern hemisphere, uncannily resemble the texture of a brain — or at the very least a brain coral!

What causes this strange landscape? Find out below:

It’s suggested that brain terrain is the result of the thermal stress and contraction, followed by sublimation, of these large ice deposits, laid down during a mid-latitude glaciation period ten to 100 million years ago. (Read more in this 2009 paper by Brown University’s Joseph Levy et al.)

This image was obtained by the HiRISE camera aboard the Mars Reconnaissance orbiter on August 23, 2013. See the original RGB color scan here.

Source: University of Arizona’s HiRISE site

How to Steal a Space Shuttle

For two days, from October 12 to 13, the shuttle Endeavour will be transported along 12 miles of road on the final leg of its journey to the California Science Center. During that time the orbiter will be the most publicly exposed as it’s ever been, a national treasure on the streets of LA. While this will of course be a well-orchestrated undertaking with the security of not only Endeavour but citizens and spectators being of utmost priority, one might be prompted to speculate: what if someone tried to steal the space shuttle?

And that one, in this instance, was Jalopnik.com‘s Jason Torchinsky. In his latest article, Jason describes in detail a method for snatching a spaceship — and a rather dramatic one at that, worthy of a Bondian supervillian (and requiring a similarly cinematic amount of funds.) However nefarious, fictitious, and unlikely, it’s nevertheless intriguing.

Now while we don’t encourage the theft of a space shuttle (or any federal property, for that matter) it’s a fun read… check it out.

Just keep an eye out for any suspicious Swiss skulking along Endeavour’s route…

(Image: NASA/Bill Ingalls)

Shuttle vs. Soyuz

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Here’s an interesting illustration showing the size comparison of a Space Shuttle to a Soyuz vehicle, shared on Twitter by NASA astronaut Rick Mastracchio (@AstroRM). Amazing to think that three flight-suited astronauts are able to fit inside a Soyuz and have life support for up to a month! (Although I’m sure most hope they won’t have to stay that long.)

Compare the 7-person capacity, 65.8 cubic meter crew cabin of an orbiter to the 3-person, 10 cubic meter space inside a Soyuz and one can imagine how cozy it must get during trips to and from the Station.

Rick is currently in training for a Soyuz flight to the ISS in November of next year as a member of the Expedition 38 crew, at which time he’ll get plenty of first-hand experience with the precise interior measurements of a Soyuz.

Thanks to Rick for sharing this! You can find out more about the Soyuz vehicles here, and check out the full source publication MIR Hardware Heritage (1995) by David S. F. Portree for Johnson Space Center.

MRO Spots Martian Dunes in Motion

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The benefit of long-term observations from orbit became evident today with the release of images from NASA’s Mars Reconnaissance Orbiter showing the subtly shifting motion of large sand dunes on the red planet, proving that the surface of Mars is much more dynamic than previously believed!

The atmosphere of Mars is extremely thin – only 1% as dense as Earth’s. This means that Martian winds would seem barely perceptible to a human, and has to blow at high speeds to move even the smallest particles on its surface.

Although scientists have known that Mars contains many dunes and vast expanses of sandy regions it has been assumed that these features must move very slowly – if at all – due to the thin air.

“We used to think of the sand on Mars as relatively immobile, so these new observations are changing our whole perspective.”

– Nathan Bridges, lead author

A rippled dune near Herschel crater undulates in the thin Martian wind. (Click to play.)

Now, images taken at different intervals by the MRO’s HiRISE camera have been seen to clearly show the shifting motion of several large sand dune features (called bedforms) in various locations on Mars.

“Mars either has more gusts of wind than we knew about before, or the winds are capable of transporting more sand,” said Nathan Bridges, planetary scientist at the Johns Hopkins University’s Applied Physics Laboratory and lead author of a paper published online in the journal Geology. “We used to think of the sand on Mars as relatively immobile, so these new observations are changing our whole perspective.”

Sandy particles on Earth that could be moved by a 10 mph breeze would require an 80 mph gust of Martian wind. Weather data and climate models have shown that such winds should be rare on Mars; these recent findings by MRO indicate that either high-speed winds are more common than once thought or else they are more capable of moving sand around… or a combination of both!

Not all of Mars’ dunes are so restless, though. The study showed that there are regions that show no movement.

“The sand dunes where we didn’t see movement today could have larger grains, or perhaps their surface layers are cemented together,” Bridges said. “These studies show the benefit of long-term monitoring at high resolution.”

Ten years ago the belief was that dunes on Mars are either static or move too slowly to detect. Thanks to MRO and the HiRISE team – and the authors of this new paper – we now know that idea is all just dust in the wind.

Read more on the NASA MRO news release.

 

Image credits: NASA/JPL-Caltech/Univ. of Ariz./JHUAPL

After Loss of Lunar Orbiter, India Looks to Mars Mission

India Moon Mission

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After giving up on re-establishing contact with the Chandrayaan-1 lunar orbiter, Indian Space Research Organization (ISRO) Chairman G. Madhavan Nair announced the space agency hopes to launch its first mission to Mars sometime between 2013 and 2015. Nair said the termination of Chandrayaan-1, although sad, is not a setback and India will move ahead with its plans for the Chandrayaan-2 mission to land an unmanned rover on the moon’s surface to prospect for chemicals, and in four to six years launch a robotic mission to Mars.


“We have given a call for proposal to different scientific communities,” Nair told reporters. “Depending on the type of experiments they propose, we will be able to plan the mission. The mission is at conceptual stage and will be taken up after Chandrayaan-2.”

On the decision to quickly pull the plug on Chandrayaan-1, Nair said, “There was no possibility of retrieving it. (But) it was a great success. We could collect a large volume of data, including more than 70,000 images of the moon. In that sense, 95 percent of the objective was completed.”

Contact with Chandrayaan-1 may have been lost because its antenna rotated out of direct contact with Earth, ISRO officials said. Earlier this year, the spacecraft lost both its primary and back-up star sensors, which use the positions of stars to orient the spacecraft.

The loss of Chandrayaan-1 comes less than a week after the spacecraft’s orbit was adjusted to team up with NASA’s Lunar Reconnaissance Orbiter for a Bi-static radar experiment. During the maneuver, Chandrayaan-1 fired its radar beam into Erlanger Crater on the moon’s north pole. Both spacecraft listened for echoes that might indicate the presence of water ice – a precious resource for future lunar explorers. The results of that experiment have not yet been released.

Chandrayaan-1 craft was designed to orbit the moon for two years, but lasted 315 days. It will take about 1,000 days until it crashes to the lunar surface and is being tracked by the U.S. and Russia, ISRO said.

The Chandrayaan I had 11 payloads, including a terrain-mapping camera designed to create a three-dimensional atlas of the moon. It is also carrying mapping instruments for the European Space Agency, radiation-measuring equipment for the Bulgarian Academy of Sciences and two devices for NASA, including the radar instrument to assess mineral composition and look for ice deposits. India launched its first rocket in 1963 and first satellite in 1975. The country’s satellite program is one of the largest communication systems in the world.

Sources: New Scientist, Xinhuanet