Returned Samples Of Asteroid Itokawa Show Violent 4.5 Billion Year History

The surface patterns on one of the microscopic dust particles from asteroid Itokawa. Image: JAXA
The surface patterns on one of the microscopic dust particles from asteroid Itokawa. Image: JAXA

In 2003, the Japanese Aerospace Exploration Agency (JAXA) launched the Hayabusa probe. Its mission was to rendezvous with asteroid 25143 Itokawa in 2005. Once there, it studied a number of things about Itokawa, including its shape, topography, composition, colour, spin, density, and history. But the most exciting part of its mission was to collect samples from the asteroid and return them to Earth.

The mission suffered some complications, including the failure of Minerva, Hayabusa’s detachable mini-lander. But Hayabusa did land on the asteroid, and it did collect some samples; tiny grains of material from the surface of Itokawa. This was the first time a mission had landed somewhere and returned samples, other than missions to the Moon.

The Hayabusa spacecraft burned up on re-entry into Earth's atmosphere, but the capsule containing the samples survived. The glowing piece on the bottom front of the debris stream is the sample capsule. Image: NASA Ames, Public Domain
The Hayabusa spacecraft burned up on re-entry into Earth’s atmosphere, but the capsule containing the samples survived. The glowing piece on the bottom front of the debris stream is the sample capsule. Image: NASA Ames, Public Domain

Once the collected grains made it back to Earth in 2010, and were confirmed to be from the asteroid, scientists got excited. These grains would be key to helping understand the early Solar System when the planetary bodies were formed. And they have revealed a sometimes violent history going back 4.5 billion years.

The grains themselves are truly microscopic, at just over 10 micrometers in size. The marks and surface patterns on them are measured in nanometers. Initially, all the marks on the surfaces of the particles were thought to be of one type. But the team behind the study used electron microscopes and X-Ray Microtomography to reveal four different types of patterns on their surfaces.

One 4.5 billion year old pattern shows crystallization from intense heat. At this time period, Itokawa was part of a larger asteroid. The second pattern indicates a collision with a meteor about 1.3 billion years ago. Another pattern was formed by exposure to the solar wind between 1 million and 1,000 years ago. A fourth pattern detected by scientists shows that the particles have been rubbing against each other.

The team has concluded that Itokawa didn’t always exist in its current shape and form. When it was formed over 4 billion years ago, it was about 40 times bigger than it is now. That parent body was destroyed, and the researchers think that Itokawa re-formed from fragments of the parent body.

If there is still any lingering doubt about the violent nature of the Solar System’s history, the grains from Itokawa help dispel it. Collision, fragmentation, bombardments, and of course solar wind, seem to be the norm in our Solar System’s history.

The return of these samples was a bit of a happy accident. The sample collection mechanism on Hayabusa suffered a failure, and the returned dust grains were actually kicked up by the landing of the probe, and some ended up in the sample capsule.

For their part, JAXA has already launched Hayabusa’s successor, Hayabusa 2. It was launched in December 2014, and is headed for asteroid 162173 Ryugu. It should reach its destination in July 2018, and spend a year and a half there. Hayabusa 2 is also designed to collect asteroid samples and return them to Earth, this time using an explosive device to dig into the asteroid’s surface for a sample. Hayabusa 2 should return to Earth in December 2020.

An artist's image of Hayabusa leaving Earth. Image credit: JAXA
An artist’s image of Hayabusa leaving Earth. Image credit: JAXA

Hayabusa suffered several failures, including the failure of its mini-lander, problems with sample collection, and it even suffered damaged to its solar panels caused by a solar flare, which reduced its power and delayed its arrival at Itokawa. Yet it still ended up being a success in the end.

If Hayabusa 2 can avoid some of these problems, who knows what we may learn from more intentional samples. Sample missions are tricky and complex. If Hayabusa can return samples, it would be only the fourth body to have samples successfully returned to Earth, including the Moon, asteroid Itokawa, and comet Wild 2.

Good News, Martian Colonists Can Eat All the Radishes They Want

Screenshot from the The Martian, showing character Mark Watney tend to his Martian potato crop. Credit: Twentieth Century Fox Film Corporation

When your stated purpose is to send settlers to Mars by 2026, you’re sure to encounter a lot of skepticism. And that is exactly what Dutch entrepreneur Bas Lansdorp has been dealing with ever since he first went public with MarsOne in 2012. In fact, in the past four years, everything from the project’s schedule, technical and financial feasibility, and ethics have been criticized by scientists, engineers and people in the aerospace industry.

However, Lansdorp and his organization have persevered, stating that they intend to overcome all the challenges in sending people on a one-way trip to the Red Planet. And in their most recent statement, MarsOne has announced that they have addressed the all-important issue of what their settlers will eat. In an experiment that feels like it was ripped from the The Martian, MarsOne has completed testing different types of crops in simulated Martian soil, to see which ones could grow on Mars.

Located in the Dutch town of Nergena, MarsOne maintains a glasshouse complex where they have been conducting experiments. These experiments took place in 2013 and 2015, and involved Martian and Lunar soil simulants provided by NASA, along with Earth soil as a control group.

Artist's impression of a Martian greenhouse. Credit: NASA/Human Systems Engineering and Development Division
A conceptual rendering of a Martian greenhouse. Credit: NASA/Human Systems Engineering and Development Division

Using these, a team of ecologists and crop scientists from the Wageningen University & Research Center have been testing different kinds of seeds to see which ones will grow in a Lunar and Martian environment. These have included rye, radishes, garden cress and pea seed. And earlier this year, they added a crop of tomatoes and potatoes to the mix.

As Dr. Wieger Wamelink, the ecologist who led the experiments, told Universe Today via email:

“We started our first experiment in 2013 (published in Plos One in 2014) to investigate if it was possible to grow plants in Mars and moon soil simulants. We assume that plants will be grown indoors, because of the very harsh circumstances on both Mars and moon, very cold, no or almost no atmosphere and way to much cosmic radiation. That first experiment only had a few crops and mostly wild plants and clovers (for nitrogen binding from the atmosphere to manure the soil).”

After confirming that the seeds would germinate in the simulated soil after the first year, they then tested to see if the seeds from that harvest would germinate in the same soil to create another harvest. What they found was quite encouraging. In all four cases, the seeds managed to germinate nicely in both Martian and Lunar soil.

Researchers at Wageningen University in the Netherlands have harvested tomatoes and other vegetables grown in simulated Martian soil. Image: regan76 CC BY 2.0
Researchers at Wageningen University in the Netherlands have harvested tomatoes and other vegetables grown in simulated Martian soil. Credit: regan76 CC BY 2.0

“Our expectation were very low,” said Wamelink, “so we were very surprised that on the Mars soil simulant plants grew rather well and even better than on our nutrient poor control earth soil. There were also problems, the biggest that it was very difficult to keep the soil moist and that though on Mars soil simulant there was growth it was not very good, i.e. the amount of biomass formed was low.”

And while they didn’t grow as well as the control group, which was grown in Earth soil, they did managed to produce time and again. This was intrinsic to the entire process, in order to make sure that any crops grown on Mars would have a full life-cycle. Being able to grow crops, replant seeds, and grow more would eliminate the need to bring new seeds for every crop cycle, thus ensuring that Martian colonists could be self-sufficient when it came to food.

In 2015, they conducted their second experiment. This time around, after planting the seeds in the simulated soil, they added organic matter to simulate the addition of organic waste from a previous crop cycle. And on every Friday, when the experiments were running, they added nutrient solution to mimic the nutrients derived from fecal matter and urine (definite echoes of The Martian there!).

Once again, the results were encouraging. Once again, the crops grew, and the addition or organic matter improved the soil’s water-holding capacity. Wamelink and his team were able to harvest from many of the ten crops they had used in the experiment, procuring another batch of radishes, tomatoes and peas. The only crop that did poorly was the batch of spinach they had added.

This year, the team’s experiments were focused on the issue of food safety. As any ecologist knows, plants naturally absorb minerals from their surrounding environment. And tests have shown that soils obtained from the Moon and Mars show concentrations of heavy metals and toxins  – such as arsenic, cadmium, copper, lead, and iron (which is what gives Mars its reddish appearance). As Wamelink described the process:

Again we have ten crops, but slightly different crops from last year; we included green beans and potatoes (best food still and Mark Watney also seems to love potatoes). Also repeated was the addition of organic matter, to mimic the addition of the plant parts that are not eaten from a previous growth cycle. Also new is the addition of liquid manure, to mimic the addition of human faeces… We know that both Mars and moon soil simulants contain heavy metals, like led, copper, mercury and chrome. The plants do not care about this, however when they end up in the eaten parts then they could poison the humans that eat them. There we have to test if it is safe to eat them.”

And again, the results were encouraging. In all cases, the crops showed that the concentrations of metals they contained were within human tolerances and therefore safe to eat. In some cases, the metal concentrations were even lower than that found those grown using potting soil.

“We now tested four species we harvested last year as a preliminary investigation and it shows that luckily there are no harmful quantities present in the fruits, so it is safe to eat them,” said Wamelink. “We will continue these analyses, because for the FDA they have to be analysed in fresh fruits and vegetables, where we did the analyses on dried material. Moreover we will also look at the content of large molecules, like vitamins, flavonoids (for the taste) and alkaloids (for toxic components).”

However, the Wageningen UR team hopes to test all ten of the crops they have grown in order to make sure that everything grown in Martian soil will be safe to eat. Towards this end, Wageningen UR has set up a crowdfunding campaign to finance their ongoing experiments. With public backing, they hope to show that future generations will be able to be self-sufficient on Mars, and not have to worry about things like arsenic and lead poisoning.

As an incentive, donors will receive a variety of potential gifts, which include samples of the soil simulant used for the experiment. But the top prize, a a dinner based on the harvest, is being offered to people contributing €500 ($555.90 USD) or more. In what is being called the first “Martian meal” this dinner will take place once the experiment is complete and will of course include Martian potatoes!

Looking ahead, Wamelink and his associates also hope to experiment crops that do not rely on a seed-to-harvest cycle, and are not harvested annually.These include fruit trees so that they might be able to grow apples, cherries, and strawberries in Martian soil. In addition, Wamelink has expressed interest in cultivating lupin seeds as a means of replacing meat in the Martian diet.

And when it comes right down to it, neither MarsOne or the Wageningen UR team are alone in wanting to see what can be grown on Mars or other planets. For years, NASA has also been engaged in their own tests to see which crops can be cultivated on Mars. And with the help of the Lima-based International Potato Center, their latest experiment involves cultivating potatoes in samples of Peruvian soil.

Artist's concept of a Martian astronaut standing outside the Mars One habitat. Credit: Bryan Versteeg/Mars One
Artist’s concept of a Martian astronaut standing outside the Mars One habitat. Credit: Bryan Versteeg/Mars One

For hundreds of years, the Andean people have been cultivating potatoes in the region. And given the arid conditions, NASA believes it will serve as a good facsimile for Mars. But perhaps the greatest draw is the fact cultivating potatoes in a simulated Martian environment immediately calls to mind Matt Damon in The Martian. In short, it’s a spectacular PR move that NASA, looking to drum up support for its “Journey to Mars“, cannot resist!

Naturally, experiments such as these are not just for the sake of meeting the challenges posed by MarsOne’s plan for one-way crewed missions to Mars. Alongside the efforts of NASA and others, they are part of a much larger effort to address the challenges posed by the renewed era of space exploration we find ourselves embarking on.

With multiple space agencies and private corporations (like SpaceX) hoping to put buts back on the Moon and Mars, and to establish permanent bases on these planets and even in the outer Solar System, knowing what it will take for future generations of colonists and explorers to sustain themselves is just good planning.

Further Reading: Mars Exchange

A Star Is About To Go 2.5% The Speed Of Light Past A Black Hole

Artist’s impression of the star S2 passing very close to the supermassive black hole at the centre of the Milky Way. Credit: ESO

Since it was first discovered in 1974, astronomers have been dying to get a better look at the Supermassive Black Hole (SBH) at the center of our galaxy. Known as Sagittarius A*, scientists have only been able to gauge the position and mass of this SBH by measuring the effect it has on the stars that orbit it. But so far, more detailed observations have eluded them, thanks in part to all the gas and dust that obscures it.

Luckily, the European Southern Observatory (ESO) recently began work with the GRAVITY interferometer, the latest component in their Very Large Telescope (VLT). Using this instrument, which combines near-infrared imaging, adaptive-optics, and vastly improved resolution and accuracy, they have managed to capture images of the stars orbiting Sagittarius A*. And what they have observed was quite fascinating.

One of the primary purposes of GRAVITY is to study the gravitational field around Sagittarius A* in order to make precise measurements of the stars that orbit it. In so doing, the GRAVITY team – which consists of astronomers from the ESO, the Max Planck Institute, and multiple European research institutes – will be able to test Einstein’s theory of General Relativity like never before.

The core of the Milky Way. Credit: NASA/JPL-Caltech/S. Stolovy (SSC/Caltech)
Spitzer image of the core of the Milky Way Galaxy. Credit: NASA/JPL-Caltech/S. Stolovy (SSC/Caltech)

In what was the first observation conducted using the new instrument, the GRAVITY team used its powerful interferometric imaging capabilities to study S2, a faint star which orbits Sagittarius A* with a period of only 16 years. This test demonstrated the effectiveness of the GRAVITY instrument – which is 15 times more sensitive than the individual 8.2-metre Unit Telescopes the VLT currently relies on.

This was an historic accomplishment, as a clear view of the center of our galaxy is something that has eluded astronomers in the past. As GRAVITY’s lead scientist, Frank Eisenhauer – from the Max Planck Institute for Extraterrestrial Physics in Garching, Germany – explained to Universe Today via email:

“First, the Galactic Center is hidden behind a huge amount of interstellar dust, and it is practically invisible at optical wavelengths. The stars are only observable in the infrared, so we first had to develop the necessary technology and instruments for that. Second, there are so many stars concentrated in the Galactic Center that a normal telescope is not sharp enough to resolve them. It was only in the late 1990′ and in the beginning of this century when we learned to sharpen the images with the help of speckle interferometry and adaptive optics to see the stars and observe their dance around the central black hole.”

But more than that, the observation of S2 was very well timed. In 2018, the star will be at the closest point in its orbit to the Sagittarius A*  – just 17 light-hours from it. As you can see from the video below, it is at this point that S2 will be moving much faster than at any other point in its orbit (the orbit of S2 is highlighted in red and the position of the central black hole is marked with a red cross).

When it makes its closest approach, S2 will accelerate to speeds of almost 30 million km per hour, which is 2.5% the speed of light. Another opportunity to view this star reach such high speeds will not come again for another 16 years – in 2034. And having shown just how sensitive the instrument is already, the GRAVITY team expects to be able make very precise measurements of the star’s position.

In fact, they anticipate that the level of accuracy will be comparable to that of measuring the positions of objects on the surface of the Moon, right down to the centimeter-scale. As such, they will be able to determine whether the motion of the star as it orbits the black hole are consistent with Einstein’s theories of general relativity.

“[I]t is not the speed itself to cause the general relativistic effects,” explained Eisenhauer, “but the strong gravitation around the black hole. But the very  high orbital speed is a direct consequence and measure of the gravitation, so we refer to it in the press release because the comparison with the speed of light and the ISS illustrates so nicely the extreme conditions.

Artist's impression of the influence gravity has on space time. Credit: space.com
Artist’s impression of the influence gravity has on space-time. Credit: space.com

As recent simulations of the expansion of galaxies in the Universe have shown, Einstein’s theories are still holding up after many decades. However, these tests will offer hard evidence, obtained through direct observation. A star traveling at a portion of the speed of light around a supermassive black hole at the center of our galaxy will certainly prove to be a fitting test.

And Eisenhauer and his colleagues expect to see some very interesting things. “We hope to see a “kick” in the orbit.” he said. “The general relativistic effects increase very strongly when you approach the black hole, and when the star swings by, these effects will slightly change the direction of the
orbit.”

While those of us here at Earth will not be able to “star gaze” on this occasion and see R2 whipping past Sagittarius A*, we will still be privy to all the results. And then, we just might see if Einstein really was correct when he proposed what is still the predominant theory of gravitation in physics, over a century later.

Further Reading: eso.org

What are the Different Masses of the Planets?

Planets and other objects in our Solar System. Credit: NASA.

It is a well known fact that the planets of the Solar System vary considerably in terms of size. For instance, the planets of the inner Solar System are smaller and denser than the gas/ice giants of the outer Solar System. And in some cases, planets can actually be smaller than the largest moons. But a planet’s size is not necessarily proportional to its mass. In the end, how massive a planet is has more to do with its composition and density.

So while a planet like Mercury may be smaller in size than Jupiter’s moon Ganymede or Saturn’s moon Titan, it is more than twice as massive than they are. And while Jupiter is 318 times as massive as Earth, its composition and density mean that it is only 11.21 times Earth’s size. Let’s go over the planet’s one by one and see just how massive they are, shall we?

Mercury:

Mercury is the Solar System’s smallest planet, with an average diameter of 4879 km (3031.67 mi). It is also one of its densest at 5.427 g/cm3, which is second only to Earth. As a terrestrial planet, it is composed of silicate rock and minerals and is differentiated between an iron core and a silicate mantle and crust. But unlike its peers (Venus, Earth and Mars), it has an abnormally large metallic core relative to its crust and mantle.

All told, Mercury’s mass is approximately 0.330 x 1024 kg, which works out to 330,000,000 trillion metric tons (or the equivalent of 0.055 Earths). Combined with its density and size, Mercury has a surface gravity of 3.7 m/s² (or 0.38 g).

Internal structure of Mercury: 1. Crust: 100–300 km thick 2. Mantle: 600 km thick 3. Core: 1,800 km radius. Credit: MASA/JPL
Internal structure of Mercury: 1. Crust: 100–300 km thick 2. Mantle: 600 km thick 3. Core: 1,800 km radius. Credit: MASA/JPL

Venus:

Venus, otherwise known as “Earth’s Sister Planet”, is so-named because of its similarities in composition, size, and mass to our own. Like Earth, Mercury and Mars, it is a terrestrial planet, and hence quite dense. In fact, with a density of 5.243 g/cm³, it is the third densest planet in the Solar System (behind Earth and Mercury). Its average radius is roughly 6,050 km (3759.3 mi), which is the equivalent of 0.95 Earths.

And when it comes to mass, the planet weighs in at a hefty 4.87 x 1024 kg, or 4,870,000,000 trillion metric tons. Not surprisingly, this is the equivalent of 0.815 Earths, making it the second most massive terrestrial planet in the Solar System. Combined with its density and size, this means that Venus also has comparable gravity to Earth – roughly 8.87 m/s², or 0.9 g.

Earth:

Like the other planets of the inner Solar System, Earth is also a terrestrial planet, composed of metals and silicate rocks differentiated between an iron core and a silicate mantle and crust. Of the terrestrial planets, it is the largest and densest, with an average radius of 6,371.0 km (3,958.8 mi) and a mean of density of 5.514 g/cm3.

The Earth's layers, showing the Inner and Outer Core, the Mantle, and Crust. Credit: discovermagazine.com
The Earth’s layers, showing the Inner and Outer Core, the Mantle, and Crust. Credit: discovermagazine.com

And at 5.97 x 1024 kg (which works out to 5,970,000,000,000 trillion metric tons) Earth is the most massive of all the terrestrial planets. Combined with its size and density, Earth experiences the surface gravity that we are all familiar with – 9.8 m/s², or 1 g.

Mars:

Mars is the third largest terrestrial planet, and the second smallest planet in our Solar System. Like the others, it is composed of metals and silicate rocks that are differentiated between a iron core and a silicate mantle and crust. But while it is roughly half the size of Earth (with a mean diameter of 6792 km, or 4220.35 mi), it is only one-tenth as massive.

In short, Mars has a mass of 0.642 x1024 kg, which works out to 642,000,000 trillion metric tons, or roughly 0.11 the mass of Earth. Combined with its size and density – 3.9335 g/cm³ (which is roughly 0.71 times that of Earth’s) – Mars has a surface gravity of 3.711 m/s² (or 0.376 g).

Jupiter:

Jupiter is the largest planet in the Solar System. With a mean diameter of 142,984 km, it is big enough to fit all the other planets (except Saturn) inside itself, and big enough to fit Earth 11.8 times over. But with a mass of 1898 x 1024 kg (or 1,898,000,000,000 trillion metric tons), Jupiter is more massive than all the other planets in the Solar System combined – 2.5 times more massive, to be exact.

upiter's structure and composition. (Image Credit: Kelvinsong CC by S.A. 3.0)
Jupiter’s structure and composition. (Image Credit: Kelvinsong CC by S.A. 3.0)

However, as a gas giant, it has a lower overall density than the terrestrial planets. It’s mean density is 1.326 g/cm, but this increases considerably the further one ventures towards the core. And though Jupiter does not have a true surface, if one were to position themselves within its atmosphere where the pressure is the same as Earth’s at sea level (1 bar), they would experience a gravitational pull of 24.79 m/s2 (2.528 g).

Saturn:

Saturn is the second largest of the gas giants; with a mean diameter of 120,536 km, it is just slightly smaller than Jupiter. However, it is significantly less massive than its Jovian cousin, with a mass of 569 x 1024 kg (or 569,000,000,000 trillion metric tons). Still, this makes Saturn the second most-massive planet in the Solar System, with 95 times the mass of Earth.

Much like Jupiter, Saturn has a low mean density due to its composition. In fact, with an average density of 0.687 g/cm³, Saturn is the only planet in the Solar System that is less dense than water (1 g/cm³).  But of course, like all gas giants, its density increases considerably the further one ventures towards the core. Combined with its size and mass, Saturn has a “surface” gravity that is just slightly higher than Earth’s – 10.44 m/s², or 1.065 g.

Diagram of Saturn's interior. Credit: Kelvinsong/Wikipedia Commons
Diagram of Saturn’s interior. Credit: Kelvinsong/Wikipedia Commons

Uranus:

With a mean diameter of 51,118 km, Uranus is the third largest planet in the Solar System. But with a mass of 86.8 x 1024 kg (86,800,000,000 trillion metric tons) it is the fourth most massive – which is 14.5 times the mass of Earth. This is due to its mean density of 1.271 g/cm3, which is about three quarters of what Neptune’s is. Between its size, mass, and density, Uranus’ gravity works out to 8.69 m/s2, which is 0.886 g.

Neptune:

Neptune is significantly larger than Earth; at 49,528 km, it is about four times Earth’s size. And with a mass of 102 x 1024 kg (or 102,000,000,000 trillion metric tons) it is also more massive – about 17 times more to be exact. This makes Neptune the third most massive planet in the Solar System; while its density is the greatest of any gas giant (1.638 g/cm3). Combined, this works out to a “surface” gravity of 11.15 m/s2 (1.14 g).

As you can see, the planets of the Solar System range considerably in terms of mass. But when you factor in their variations in density, you can see how a planets mass is not always proportionate to its size. In short, while some planets may be a few times larger than others, they are can have many, many times more mass.

We have written many interesting articles about the planets here at Universe. For instance, here’s Interesting Facts About the Solar System, What are the Colors of the Planets?, What are the Signs of the Planets?, How Dense are the Planets?, and What are the Diameters of the Planets?.

For more information, check out Nine Planets overview of the Solar System, NASA’s Solar System Exploration, and use this site to find out what you would weigh on other planets.

Astronomy Cast has episodes on all of the planets. Here’s Episode 49: Mercury to start!

HiRISE Captures Curiosity on the Naukluft Plateau

MSL Curiosity on the Naukluft Plateau on the Martian surface. This image was captured by HiRise on the Mars Reconnaissance Orbiter. Image: NASA/JPL/University of Arizona
MSL Curiosity on the Naukluft Plateau on the Martian surface. This image was captured by HiRise on the Mars Reconnaissance Orbiter. Image: NASA/JPL/University of Arizona

Viewing orbital images of the rovers as they go about their business on the surface of Mars is pretty cool. Besides being of great interest to anyone keen on space in general, they have scientific value as well. New images from the High Resolution Imaging Science Equipment (HiRise) camera aboard the Mars Reconnaissance Orbiter (MRO) help scientists in a number of ways.

Recent images from HiRise show the Mars Science Laboratory (MSL) Curiosity on a feature called the Naukluft Plateau. The Plateau is named after a mountain range in Namibia, and is the site of Curiosity’s 10th and 11th drill targets.

Orbital imagery of the rovers is used to track the activity of sand dunes in the areas the rovers are working in. In this case, the dune field is called the Bagnold Dunes. HiRise imagery allows a detailed look at how dunes change over time, and how any tracks left by the rover are filled in with sand over time. Knowledge of this type of activity is a piece of the puzzle in understanding the Martian surface.

Curiosity on the Naukluft Plateau as captured by HiRise. Image: NASA/JPL/University of Arizona
Curiosity on the Naukluft Plateau as captured by HiRise. Image: NASA/JPL/University of Arizona

But the ability to take such detailed images of the Martian surface has other benefits, as well. Especially as we get nearer to a human presence on Mars.

Orbital imaging is turning exploration on its ear. Throughout human history, exploration required explorers travelling by land and sea to reconnoiter an area, and to draw maps and charts later. We literally had no idea what was around the corner, over the mountain, or across the sea until someone went there. There was no way to choose a location for a settlement until we had walked the ground.

From the serious (SpaceX, NASA) to the fanciful (MarsOne), a human mission to Mars, and an eventual established presence on Mars, is a coming fact. The how and the where are all connected in this venture, and orbital images will be a huge part of choosing where.

Tracking the changes in dunes over time will help inform the choice for human landing sites on Mars. The types and density of sand particles may be determined by monitoring rover tracks as they fill with sand. This may be invaluable information when it comes to designing the types of facilities used on Mars. Critical infrastructure in the form of greenhouses or solar arrays will need to be placed very carefully.

Sci-Fi writers have exaggerated the strength of sand storms on Mars to great effect, but they are real. We know from orbital monitoring, and from rovers, that Martian sandstorms can be very powerful phenomena. Of course, a 100 km/h wind on Earth is much more dangerous than on Mars because of the density of the atmosphere. Martian air is 1% the density of Earth’s, so on Mars the 100 km/h wind wouldn’t do much.

But it can pick up dust, and that dust can foul important equipment. With all this in mind, we can see how these orbital images give us an important understanding of how sand behaves on Mars.

This Martian sandstorm was captured by the MRO's Mars Color Imager instrument. Scientists were monitoring such storms prior to Curiosity's arrival on Mars. Image: NASA/JPL-Caltech/MSSS
This Martian sandstorm was captured by the MRO’s Mars Color Imager instrument. Scientists were monitoring such storms prior to Curiosity’s arrival on Mars. Image: NASA/JPL-Caltech/MSSS

There’s an unpredictability factor to all this too. We can’t always know in advance how important or valuable orbital imagery will be in the future. That’s part of doing science.

But back to the cool factor.

For the rest of us, who aren’t scientists, it’s just plain cool to be able to watch the rovers from above.

And, look at all the Martian eye candy!

These sand dunes in the southern hemisphere of Mars are just starting their seasonal defrost of carbon dioxide. Image: NASA/JPL/University of Arizona
These sand dunes in the southern hemisphere of Mars are just starting their seasonal defrost of carbon dioxide. Image: NASA/JPL/University of Arizona

Centaurs Keep Their Rings From Greedy Gas Giants

Artist's impression of what the rings of the asteroid Chariklo would look like from the small body's surface. The rings' discovery was a first for an asteroid. Credit: ESO/L. Calçada/Nick Risinger (skysurvey.org)

When we think of ring systems, what naturally comes to mind are planets like Saturn. It’s beautiful rings are certainly the most well known, but they are not the only planet in our Solar System to have them. As the Voyager missions demonstrated, every planet in the outer Solar System – from Jupiter to Neptune – has its own system of rings. And in recent years, astronomers have discovered that even certain minor planets – like the Centaur asteroids 10199 Chariklo and 2006 Chiron – have them too.

This was a rather surprising find, since these objects have such chaotic orbits. Given that their paths through the Solar System are frequently altered by the powerful gravity of gas giants, astronomers have naturally wondered how a minor planet could retain a system of rings. But thanks to a team of researchers from the Sao Paulo State University in Brazil, we may be close to answering that question.

In a study titled “The Rings of Chariklo Under Close Encounters With The Giant Planets“, which appeared recently in The Astrophysical Journal, they explained how they constructed a model of the Solar System that incorporated 729 simulated objects. All of these objects were the same size as Chariklo and had their own system of rings. They then went about the process of examining how interacting with gas giant effected them.

Artist's impression of rings around the asteroid Chariklo. This was the first asteroid where rings were discovered. Credit: ESO/L. Calçada/M. Kornmesser/Nick Risinger (skysurvey.org)
Artist’s impression of rings around the Centaur Chariklo, the first asteroid where rings were discovered. Credit: ESO/L. Calçada/M. Kornmesser/Nick Risinger (skysurvey.org)

To break it down, Centaurs are a population of objects within our Solar System that behave as both comets and asteroids (hence why they are named after the hybrid beasts of Greek mythology). 10199 Chariklo is the largest known member of the Centaur population, a possible former Trans-Neptunian Object (TNO) which currently orbits between Saturn and Uranus.

The rings around this asteroid were first noticed in 2013 when the asteroid underwent a stellar occultation. This revealed a system of two rings, with a radius of 391 and 405 km and widths of about 7 km 3 km, respectively. The absorption features of the rings showed that they were partially composed of water ice. In this respect, they were much like the rings of Jupiter, Saturn, Uranus and the other gas giants, which are composed largely of water ice and dust.

This was followed by findings made in 2015 that indicated that 2006 Chiron – another major Centaur – could have a ring of its own. This led to further speculation that there might be many minor planets in our Solar System that have a system of rings. Naturally, this was a bit perplexing to astronomers, since rings are fragile structures that were thought to be exclusive to the gas giants of our System.

As Professor Othon Winter, the lead researcher of the Sao Paulo team, told Universe Today via email:

“At first it was a surprise to find a Centaur with rings, since the Centaurs have chaotic orbits wandering between the giant planets and having frequent close encounters with them. However, we have shown that in most of the cases the ring system can survive all the close encounters with the giant planets. Therefore,  Centaurs with rings might be much more common than we thought before.”

Arist's impression of Chiron and its possible ring. Credit: dailygalaxy.com
Artist’s impression of Chiron, showing a possible ring system. Credit: dailygalaxy.com

For the sake of their study, Winter and his colleagues considered the orbits of 729 simulated clones of Chariklo as they orbited the Sun over the course of 100 million years. From this, Winter and his colleagues found that each Centaur averaged about 150 close encounters with a gas giant, within one Hill radius of the planet in question. As Winter described it:

“The study was made in two steps. First we considered a set of more than 700 clones of Chariklo. The clones had initial trajectories that were slightly different from Chariklo for statistical purposes (since we are dealing with chaotic trajectories) and computationally simulated their orbital evolution forward in time (to see their future) and also backward in time (to see their past). During these simulations we archived the information of all the close encounters (many thousands) they had with each of the giant planets.”

“In the second step, we performed simulations of each one of the close encounters found in the first step, but now including a disk of particles around Chariklo  (representing the ring particles). Then, at the end of each simulation we analyzed what happened to the particles. Which ones were removed from Chariklo  (escaping its gravitational field)? Which ones were strongly disturbed (still orbiting around Chariklo)? Which ones did not suffer any significant effect?”

In the end, the simulations showed that in 90 percent of the cases, the rings of the Centaurs survived their close encounters with gas giants, whereas they were disturbed in 4 percent of cases, and were stripped away only 3 percent of the time. Thus, they concluded that if there is an efficient mechanism that creates the rings, then it is strong enough to let Centaurs keep them.

Due to their dual nature, astronomers refer to asteroids that behave as both comets and asteroids as Centaurs. Credit: jpl.nasa.gov
Due to their dual nature, the name Centaur has stuck when referring to objects that act as both comets and asteroids. Credit: jpl.nasa.gov

More than that, their research would seem to indicate that what was considered unique to certain planetary bodies may actually be more commonplace. “It reveals that our Solar System is complex not just as whole or for large bodies,” said Winter, “but even small bodies may show complex structures and even more complex temporal evolution.”

The next step for the research team is to study ring formation, which could show that they in fact picking them up from the gas giants themselves. But regardless of where they come from, its becoming increasingly clear that Centaurs like 10199 Chariklo are not alone. What’s more, they aren’t giving up their rings anytime soon!

Further Reading: iopscience.iop.org

Can Boeing Launch A Crewed Starliner By February 2018?

Boeing is competing with SpaceX to be the first American company to provide commercial crew capabilities to NASA. Image: Boeing
Boeing is competing with SpaceX to be the first American company to provide commercial crew capabilities to NASA. Image: Boeing

Boeing thinks it can have its Starliner spacecraft ready to fly crewed missions by February, 2018. This is 4 months later than the previous date of October 2017. It isn’t yet clear what this will mean in Boeing’s race against SpaceX to relieve NASA’s dependence on Russian transportation to the ISS.

Currently, astronauts travel to the ISS aboard the Russian workhorse Soyuz capsule. Ever since the end of the Space Shuttle program, NASA has relied on Russia to transport astronauts to the station. Both Boeing and SpaceX have received funds to develop a crewed capsule, and both companies are working at a feverish pace to be the first to do so.

Boeing has a long history of involvement with NASA. It’s the prime contractor for ISS operations, and is also the prime contractor for NASA’s Space Launch System (SLS), which will be the most powerful rocket ever built and will power NASA’s exploration of deep space. So Boeing is no stranger to complex development cycles and the types of delays that can crop up.

In a recent interview, Boeing’s Chris Ferguson acknowledged that everything has to go well for the Starliner to meet its schedule. But things don’t always go well in such a complex engineering program, and that’s just the way things are.

The Starliner, and every other spacecraft, has to undergo extensive testing of each component before any flight can be attempted. Various suppliers are responsible for over 200 pieces of equipment, just in avionics alone, and each one of those pieces has to assembled, integrated, and tested. Not just by Boeing, but by NASA as well. This takes an enormous amount of time, and requires great rigor to carry out. In some cases, a problem with one piece of equipment can delay testing of other pieces. It’s the nature of complex systems.

Another challenge that Boeing engineers face is limiting the mass of the spacecraft. Recent wind-tunnel testing of a Starliner model produced aero-acoustic issues when mated to a model of the Atlas 5, the rocket built by United Launch Alliance (ULA) which will carry the Starliner into space. Now Boeing is modifying the exterior lines of the vehicle to get the airflow just right.

The spacecraft also has to be tested for emergencies. Though the Starliner is designed to land on solid ground, it’s also being tested for emergency landings on water.

NASA blames the delays in the development of the Starliner, and the SpaceX Dragon, on funding cuts from Congress. Administrator Charles Bolden has criticized Congress for consistent under-funding since the retirement of the Space Shuttle fleet in 2011. According to NASA, this has caused a 2 year delay in development of the Dragon and the Starliner. This delay, in turn, has meant that NASA has had to keep paying Russia for trips to the ISS. And like everything else, that cost keeps rising.

But it looks like the end, or maybe the beginning, is in sight for the Starliner. Boeing has paid deposits to ULA for four flights with the Atlas 5. A 2017 un-crewed test flight, a 2018 crewed test flight, and two crewed flights to the ISS.

Beyond that, the future looks a little hard to predict for Boeing and the Starliner. With both SpaceX and Blue Origin developing re-usable rockets, the future viability of the Atlas 5 might be in jeopardy. Compounding the uncertainty is NASA’s stated plan to stop funding the ISS by 2024 or 2028.
By that time, NASA should be focused on establishing a presence in cislunar space, which would require different spacecraft.

But you can’t wait forever to develop spacecraft. The only way to stay in the game is for Boeing to develop the spacecraft that are required right now, and let the knowledge and experience from that feed the development of the next spacecraft, whether for cislunar space or beyond.

In the big scheme of things, a four month delay for the first flight of the Starliner is not that big of a deal. If the Starliner is successful, and there’s no reason to think it won’t be, considering Boeing’s track record, the four month delay in the initial flight won’t even be remembered.

Whether its SpaceX or Boeing who get America back into space first, that moment will be celebrated, and all the delays and funding cuts will be left in the dust-bin of history.

Time For NASA To Double Down On Journey To Mars

Looking to the future of space exploration, NASA and TopCoder have launched the "High Performance Fast Computing Challenge" to improve the performance of their Pleiades supercomputer. Credit: NASA/MSFC

Since the Authorization Act of 2010, NASA has been pushing ahead with the goal of sending astronauts to Mars by the 2030s. The latter part of this goal has been the subject of much attention in recent years, and for good reason. Sending crewed missions to the Red Planet would be the single-greatest initiative undertaken since the Apollo era, and the rewards equally great.

However, with the scheduled date for a mission approaching, and the upcoming presidential election, NASA is finding itself under pressure to show that they are making headway. Despite progress being made with both the Space Launch System (SLS) and the Orion Multi-Purpose Crew Vehicle, there are lingering issues which need to be worked out before NASA can mount its historic mission to Mars.

One of the biggest issues is that of assigned launched missions that will ensure that the SLS is tested many times before a crewed mission to Mars is mounted. So far, NASA has produced some general plans as part of it’s “Journey to Mars“, an important part of which is the use of the SLS and Orion spacecraft to send a crew beyond low-Earth orbit and explore a near-Earth asteroid by 2025.

NASA's Journey to Mars. NASA is developing the capabilities needed to send humans to an asteroid by 2025 and Mars in the 2030s. Credit: NASA/JPL
NASA’s Journey to Mars. NASA is developing the capabilities needed to send humans to an asteroid by 2025 and Mars in the 2030s. Credit: NASA/JPL

This plan is not only intended to provide their astronauts with experience working beyond LEO, but to test the SLS and Orion’s capabilities, not to mention some vital systems – such as Solar Electric Propulsion (SEP), which will be used to send cargo missions to Mars. Another major step is  Exploration Mission 1 (EM-1), the first planned flight of the SLS and the second uncrewed test flight of the Orion spacecraft (which will take place on September 30th, 2018).

However, beyond this, NASA has only one other mission on the books, which is Exploration Mission 2 (EM-2). This mission will involve the crew performing a practice flyby of a captured asteroid in lunar orbit, and which is scheduled for launch in 2023. This will be the first crewed test of the Orion spacecraft, and also the first time American astronauts have left low-Earth orbit since the Apollo 17 mission in 1972.

While significant, these mission remain the only two assigned flights for the SLS and Orion. Beyond these, dozens more have been proposed as part of NASA’s three phase plan to reach Mars. For instance, between 2018 and the 2030s, NASA would be responsible for launching a total of 32 missions in order to send the necessary hardware to near-Mars space before making crewed landings on Phobos and then to Mars.

In accordance with the “Evolvable Mars Campaign” – which was presented last year by NASA’s Human Exploration and Operations Mission Directorate (HEOMD) – Phase One (the “Earth Reliant” phase) of this plan would involve two launches in 2028, which would be responsible for transporting a habitation module, an SEP module, and a exploration vehicle to cis-lunar space.

This would be followed by two SLS flights in 2029, bringing the Trans-Earth Injection (TEI) stage to cis-lunar space, followed by a crew to perform the final checks on the Phobos Hab. By 2030, Phase Two (known as the “Proving Ground” phase) would begin with the last elements – the Earth Orbit Insertion (EOI) stage and taxi elements – being launched to cis-lunar orbit, and then all the equipment being sent to near-Mars space for pre-deployment.

By 2031, two more SLS missions would take place, where a Martian Hab would be launched, followed in 2032 by the launches of the Mars Orbit Insertion (MOI) and Trans-Mars Injection (TMI) stages. By 2033, Phase Three (the “Earth Independent” phase) would begin, where the Phobos crew would be transported to the Transit Hab, followed by the final crewed mission to the Martian surface.

Accomplishing all of this would require that NASA commit to making regular launches over the next few years. Such was the feeling of Bill Gerstenmaier – NASA’s Associate Administrator for Human Exploration and Operations – who recently indicated that NASA will need to mount launches at least once a year to establish a “launch cadence” with the SLS.

Mission proposals of this kind were also discussed at the recent Aerospace Safety Advisory Panel (ASAP) meeting – which meets annually to discuss matters relating to NASA’s safety performance. During the course of the meeting, Bill Hill – the Deputy Associate Administrator for Exploration Systems Development (ESD) in NASA’s Human Exploration and Operations Mission Directorate (HEOMD) – provided an overview of the latest developments in NASA’s planned mission.

The many faces of Mars inner moon, Phobos (Credit: NASA)
The many faces of Mars inner moon, Phobos. Credit: NASA

By and large, the meeting focused on possible concepts for the Mars mission, which included using SEP and chemical propellants for sending hardware to cis-lunar space and near-Mars space, in advance of a mission to Phobos and the Martian surface. Two scenarios were proposed that would rely to these methods to varying extents, both of which called for a total of 32 SLS launches.

However, the outcome of this meeting seemed to indicate that NASA is still thinking over its long-term options and has not yet committed to anything beyond the mission to a near-Earth asteroid. For instance, NASA has indicated that it is laying the groundwork for Phase One of the Mars mission, which calls for flight testing to cis-lunar space.

However, according to Hill, NASA is currently engaged in “Phase 0” of the three phase plan, which involves the use of the ISS to test crew health via long duration space flight. In addition, there are currently no plans for developing Phases Two and Three of the mission. Other problems, such as the Orion spacecraft’s heatshield – which is currently incapable of withstanding the speed of reentry coming all the way from Mar – have yet to be resolved.

Another major issue is that of funding. Thanks to the Obama administration and the passage of the Authorization Act of 2010, NASA has been able to take several crucial steps towards developing their plan for a mission to Mars. However, in order to take things to the next level, the US government will need to show a serious commitment to ensuring that all aspects of the plan get the funding they need.

And given that it is an election year, the budget environment may be changing in the near future. As such, now is the time for the agency to demonstrate that it is fully committed to every phase of its plan to puts boots on the ground of Mars.

On the other hand, NASA has taken some very positive strides in the past six years, and one cannot deny that they are serious about making the mission happen in the time frame it has provided. They are also on track when it comes to proving key concepts and technology.

In the coming years, with flight tests of the SLS and crewed tests of the Orion, they will be even further along. And given the support of both the federal government and the private sector, nothing should stand in the way of human boots touching red soil by the 2030s.

Artist's concept image of a boot print on the moon and on Mars. Credit: NASA/JPL-Caltech
Artist’s concept image of a boot print on the moon and on Mars. Credit: NASA/JPL-Caltech

Further Reading: NASA Spaceflight.com

Port Canaveral Considers Charging SpaceX 14 Times Normal Fee For Booster Return

A recovered Falcon 9 first stage arriving in port on-board the drone ship. Image: SpaceX
A recovered Falcon 9 first stage arriving in port on-board the drone ship. Image: SpaceX

A dispute may be brewing between SpaceX and the Canaveral Port Authority, where the private space company brings its recovered boosters back to land. Citing concerns over wear and tear on the port’s facilities, the Authority is considering raising SpaceX’s fees by 14 times, to a total of $15,000 for each booster passing through.

Port Canaveral is the facility that SpaceX relies on in its operations. Spent boosters are recovered aboard their drone ship, which docks at the Port. They are then offloaded from the drone ship with SpaceX’s special crane, loaded onto a truck and delivered to Kennedy Space Center.

All of this activity puts a special strain on the Port’s facilities, according to Rodger Rees, the port’s deputy executive director and chief financial officer. In a memo to port commissioners, he said “Due to the heavy weight and the effect of this weight on the port’s berths, staff is recommending that the tariff be expanded to include a wharfage charges category for aerospace/aircraft items.”

So far, SpaceX has transported 3 recovered boosters through Port Canaveral. The rationalization for the fee increase is based on some minor damage caused to the Port, and on the increased wear and tear that 30 ton boosters will have on the Port and its structures. SpaceX’s special crane also takes up space at the Port.

A SpaceX Falcon 9 reusable first stage lands on the drone ship before being transported to Port Canaveral. Image: SpaceX
A SpaceX Falcon 9 reusable first stage lands on the drone ship before being transported to Port Canaveral. Image: SpaceX

But SpaceX isn’t being singled out. The Port is trying to develop a fee structure for private space companies, who are expected to proliferate in the future and require port facilities the same way SpaceX does.

“As new aerospace companies relocate to the Space Coast, it is anticipated that the port will need to accommodate items of a similar nature in the future, and will retain the right to negotiate these future charges, if needed,” said Rees in the same memo.

The fees themselves are a result of research into what other ports charge for oversized items. Staff at Port Canaveral have recommended charging $500 a ton or $15,000 per item, whichever amount is greater. In his memo to the port’s commissioners, Rees also said “Staff understands that the current Falcon first stage weighs approximately 30 tons when it arrives in the port on the drone ship. Under this weight, it is anticipated that each time the rocket stage is transported over the berth, a charge of $15,000 will be assessed and collected from the owner of the item.”

Rees made note of the cool factor that having SpaceX recover boosters at their facility gives the Port. SpaceX’s use of the Port attracts a lot of public interest, which also creates additional security and logistical considerations for the Port.

SpaceX has indicated that it is concerned with the raise in fees. Representatives from Port Canaveral and SpaceX are due to discuss the issue at a meeting on Wednesday, June 22nd.

Huge Plasma Tsunamis Hitting Earth Explains Third Van Allen Belt

This is an illustration to explain the dynamics of the ultra-relativistic third Van Allen radiation belt. Credit: Andy Kale
This is an illustration to explain the dynamics of the ultra-relativistic third Van Allen radiation belt. Credit: Andy Kale

The dynamic relationship between Earth and the Sun two sides. The warmth from the Sun makes life on Earth possible, but the rest of the Sun’s intense energy pummels the Earth, and could destroy all life, given the chance. But thanks to our magnetosphere, we are safe.

The magnetosphere is our protective shield. It’s created by the rotation of the molten outer core of the Earth, composed largely of iron and nickel. It absorbs and deflects plasma from the solar wind. The interactions between the magnetosphere and the solar wind are what create the beautiful auroras at Earth’s poles.

Visualization of the solar wind encountering Earth's magnetic "defenses" known as the magnetosphere. Clouds of southward-pointing plasma are able to peel back layers of the Sun-facing bubble and stack them into layers on the planet's nightside (center, right). The layers can be squeezed tightly enough to reconnect and deliver solar electrons (yellow sparkles) directly into the upper atmosphere to create the aurora. Credit: JPL
Visualization of the solar wind encountering Earth’s magnetic “defenses” known as the magnetosphere. Clouds of southward-pointing plasma are able to peel back layers of the Sun-facing bubble and stack them into layers on the planet’s nightside (center, right). The layers can be squeezed tightly enough to reconnect and deliver solar electrons (yellow sparkles) directly into the upper atmosphere to create the aurora. Credit: JPL

In the inner regions of Earth’s magnetosphere are the Van Allen belts, named after their discoverer James Van Allen. They consist of charged particles, mostly from the Sun, and are held in place by the magnetosphere. Usually, there are two such belts.

The Van Allen radiation belts surrounding Earth. Image: NASA
The Van Allen radiation belts surrounding Earth. Image: NASA

But the output from the Sun is not stable. There are periods of intense energy output from the Sun, and when that happens, a third, transient belt can be created. Up until now, the nature of this third belt has been a puzzle. New research from the University of Alberta has shown how this phenomena can happen.

Researchers have shown how a so-called “space tsunami” can create this third belt. Intense ultra-low frequency plasma waves can transport the outer part of the radiation belt into interplanetary space, and create the third, transient belt.

The lead author for this study is physics professor Ian Mann from the University of Alberta, and former Canada Research Chair in Space Physics. “Remarkably, we observed huge plasma waves,” said Mann. “Rather like a space tsunami, they slosh the radiation belts around and very rapidly wash away the outer part of the belt, explaining the structure of the enigmatic third radiation belt.”

This new research also sheds light on how these “tsunamis” help reduce the threat of radiation to satellites during other space storms. “Space radiation poses a threat to the operation of the satellite infrastructure upon which our twenty-first century technological society relies,” adds Mann. “Understanding how such radiation is energized and lost is one of the biggest challenges for space research.”

It’s not just satellites that are at risk of radiation though. When solar wind is most active, it can create extremely energetic space storms. They in turn create intense radiation in the Van Allen belts, which drive electrical currents that could damage our power grids here on Earth. These types of storms have the potential to cause trillions of dollars worth of damage.

A better understanding of this space radiation, and an ability to forecast it, are turning out to be very important to our satellite operations, and to our exploration of space.

The Van Allen belts were discovered in 1958, and classified into an inner and an outer belt.

The Van Allen Belts around Earth. The inner red belt is mostly protons, and the outer blue belt is mostly electrons. Image Credit: NASA
The Van Allen Belts around Earth. The inner red belt is mostly protons, and the outer blue belt is mostly electrons. Image Credit: NASA

In 2013, probes reported a third belt which had never before been seen. It lasted a few weeks, then vanished, and its cause was not known. Thanks to Mann and his team, we now know what was behind that third belt.

“We have discovered a very elegant explanation for the dynamics of the third belt,” says Mann. “Our results show a remarkable simplicity in belt response once the dominant processes are accurately specified.”

An understanding of the radiation in and around Earth and the Van Allen belts is of growing importance to us, as we expand our presence in space. Our technological society relies increasingly on satellite communications, and on GPS satellites. Radiation in the form of high-energy electrons can wreak havoc on satellites. In fact, this type of radiation is sometimes referred to as a satellite killer. Satellites require robust design to be protected from them.

Organizations like the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) and the International Living with a Star (ILWS) Program are attempts to address the threat that radiation poses to our system of satellites.