Lucy’s Principal Investigator discusses upcoming mission to Jupiter’s Trojans

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Lucy’s Principal Investigator discusses upcoming mission to Jupiter’s Trojans

Of the varying types of celestial objects humans have sent spacecraft to investigate, there remains a select group of asteroids, located in two separate locations in our solar system, that we have yet to visit — the Trojan asteroids.

Trojan asteroids are located at Jupiter’s L4 and L5 Lagrange points, 60 degrees ahead of and 60 degrees behind Jupiter, respectively. The asteroids are present at the Lagrange points in groups, sometimes referred to as “swarms” or “camps.”

Although telescopes have allowed scientists to research asteroids from Earth, the nature of the Trojans remains largely unknown. However, this is set to change.

No earlier than October 16, the Lucy mission will start a 12-year journey to visit six of these mysterious asteroids and an additional main-belt asteroid. During its time with the Trojans, Lucy will uncover the history behind these bodies and study the Trojans in depth using a suite of cameras, spectrometers, and antennas.

But why Trojan asteroids?

“Asteroids are the fossils of planet formation. They’re left over from early on, and they’ve remained relatively unchanged, at least relative compared to the planets since they formed,” said Dr. Hal Levison, Principal Investigator for Lucy at the Southwest Research Institute (SwRI) in an interview with NASASpaceflight.

The planned orbit for Lucy. Credit: NASA

“I’m actually a theorist by training. This is the first space mission I’ve been involved in. My background is to do large-scale planet formation models and try to figure out the small body reservoirs because of what the fossils of planet formation tell us about how the planets formed,” added Dr. Levison.

“If you look at the major small body reservoirs that are accessible by spacecraft, the only ones yet to be visited are the Trojans. We’re sort of putting a bow around the initial exploration of the small body reservoirs with this mission.”

Despite going to the Trojans, Lucy will first visit the main-belt asteroid Donaldjohanson, performing a flyby on April 20, 2025. This target will largely serve as a dress-rehearsal flyby for Lucy’s teams; however, they are still interested in seeing Donaldjohanson’s surface features.

And this relates to the type of asteroids Lucy will visit in the Trojan camps.

“[The Trojans] occupy a very small region of orbital space. They’re very different from one another, particularly in their colors. They go from gray (C-type) to actually pretty red (D-type). That diversity, I think, is telling us something about their history.”

Lucy will also visit P-type Trojan asteroids, which in terms of color are between gray and red.

Dr. Levison added that the color is likely an indication of where the asteroids now trapped in Jupiter’s L4 and L5 points originally formed in relation to the Sun.

“The Kuiper Belt, for example, is a lot redder than the Trojans, which are a lot redder than the asteroid belt. Exactly how that works, we don’t know.”

“So [this is] an opportunity for several reasons. First of all, if you imagine you were to go to the gray objects in the asteroid belt and the red objects in the Kuiper Belt, it’s going to be almost impossible to detangle the evolutionary differences they experienced from their intrinsic differences.”

“The beauty of the Trojans is that they’ve been hanging out in the same place on very similar orbits for long periods of time. Therefore, the differences that we see are going to be intrinsic differences rather than evolutionary differences.”

And Lucy will be able to help sift through part of that mystery.

“We have instrumentation, particularly the Ralph instrument, half of which is a near-infrared spectrograph. Hopefully, we’re going to be able to figure out the chemistry that makes these things red as we fly by because we can’t do it from the ground.”

Moreover, the teams have several working hypotheses based on data gathered elsewhere in the solar system. Dr. Levison continued: “I think whatever makes these things red is only skin deep, and when you break them open, they’re gray inside. Lucy will be able to directly test the second hypothesis because if that’s true, when we get to our red objects, young craters should be gray.”

Artist impression of Lucy’s targets. Credit: NASA

One of the surface processing features that could be in play with the redder, D-type Trojans is that they were exposed to ice that is only stable beyond 20 AU distance (with a single AU being approximately 149 million km) from the Sun. The Trojans captured at Jupiter are located an average 5.2 AU distance from the Sun, far too close for the known process to work. Unless they formed farther out.

Of course, as Dr. Levison points out, “That’s one thing you can imagine. Hopefully, the data we collect will help us understand if an idea like this is true. Because if you can say, ‘Ah, the red guys all formed beyond 20 AU,’ for example, then you look at the mixing ratio in the Trojans between red and gray and that puts constraints on how the giant planets moved around.”

This potential bounding of how the giant planets migrated in the early solar system is a key part of Dr. Levison’s work as one of the authors of the Nice model of solar system formation. This theory postulates that — among other things — the giant planets first formed closer to the Sun and then migrated out to their current positions due to gravitational perturbations.

Part of the Nice theory also holds that Neptune and Uranus originally formed in opposite locations as the seventh and eighth planets, respectively, before gravity flung Neptune outward and made it the eighth planet from the Sun.

Under this model, Neptune would have greatly perturbed the scattered disk and flung objects — redder D and P-type asteroids — into the solar system.

Back to the idea of Lucy’s mission being able to help understand how the giant planets migrated, “[The red Trojans] tell you that you got almost all the stuff from beyond 20 AU captured, but almost none of the stuff inside of 20 AU. That’s the game we can eventually play to answer these pretty fundamental questions of how the giant planets moved around … by measuring colors on the surface of Trojans.”

“Now … if we find red craters on gray objects, we don’t know [what’s going on out there]. We’ll need data in order to answer this.”

And that last statement is key to Lucy’s mission. “The reason why I went from being a theorist to doing a spacecraft mission was basically the realization that when I started in this field, we had more problems than we had ideas. Now we have more ideas than we have data. We can’t tell which of our ideas are right with the data we have. It became clear to me that developing more theories isn’t going to be as useful as going off and trying to collect the data that will help us determine which of our ideas are right.”

Another target for Lucy that could hopefully shed light on early solar system formation is Patroclus. This will be the last Trojan to be visited and is a near-equal mass binary with Menoetius.

“They’re exactly the same size with a circular orbit … which is, if you think about it, really huge,” said Dr. Levison. “It turns out [the odds of this are] high because it’s a very unusual object in what I’ll call the inner parts of the solar system. And, in this case, I mean inside the orbit of Neptune, in the planetary region.”

Artist’s rendering of Lucy performing a Trojan flyby. (Credit: Southwest Research Institute)

“If you go out into the Kuiper Belt, there’s a part of the Kuiper Belt called the Cold Classical Kuiper Belt, which is believed to be undisturbed from the original accretion of the first stuff. When we look with [the Hubble Space Telescope], almost all of them are binaries like this.”

“It’s biased, but at least half, let’s say, are binaries. I think what that’s telling us is the first macroscopic objects to form in the solar system were these binaries, and they’re now models that would actually predict that. If that’s true, then Patroclus is one of the remnants of that really early population that just happens to survive. It’s probably extremely primordial, and that’s why I think for somebody who’s interested in planet formation, seeing one of these things close up — it’s going to be cool.”

When asked about potential surprising finds from Lucy at the Trojans, Dr. Levison replied that finding red D-type Trojans with red craters (instead of gray) would be surprising given how the reddish color is thought to form.

Another surprise would be if Patroclus and Menoetius are different from each other. “All these theories I was talking about with the Cold Classical Kuiper Belt models, [they] say that they form together. If they’re very different from one another, I’d be very surprised because that is an argument that they didn’t form together. I could think of a couple of things, but we just have to go and find out. That’s why they call it exploration.”

Lucy is currently set to begin its exploration of the Jupiter Trojans with a launch no earlier than October 16, 2021, at 5:34 am EDT (09:34 UTC) from SLC-41 at the Cape Canaveral Space Force Station on a United Launch Alliance Atlas V 401 rocket.

The launch period remains open for 21 days, with an approximately 60-minute launch window each day.

(Lead image: Artist’s depiction of Lucy performing a Trojan encounter. Credit: Southwest Research Institute)

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Inside Varda Space’s plans to revolutionize in-space manufacturing

The idea of manufacturing commodities in space is not a novel concept. The International Space… The post Inside Varda Space’s plans to revolutionize in-space manufacturing appeared first on

Inside Varda Space’s plans to revolutionize in-space manufacturing

The idea of manufacturing commodities in space is not a novel concept. The International Space Station — humanity’s hub for research and development in microgravity — has hosted several research payloads which have produced Optic Fibers and even 3D printed STEM cells. These may have the potential of printing entire human organs in space, saving countless lives.

This technology utilizes the microgravity environment to produce commodities that cannot be made on Earth. Now, a California-based in-space manufacturing company named Varda Space is looking to transition this technology from research to production.

Varda Space is looking to increase access to manufacturing in space, as it provides an environment with characteristics unavailable on Earth. They hope to accomplish this onboard free-flying satellite platforms in Low Earth Orbit (LEO), using in-house technologies and equipment.

“Our technology that we have been working on has been demonstrated in the International Space Station by a variety of researchers. We’re just helping to commercially transition that research from the ISS to our independent satellite platform,” said Delian Asparouhov, Co-Founder and President of Varda, during an interview with

NASA astronaut Butch Wilmore holds the first object 3D printed in space, aboard the International Space Station. Credit: NASA.

Varda has raised over $53 Million since its inception ten months ago. Of this, $42 million was raised in the Series A round, co-led by venture capital firms Khosla Ventures (primary backers of Rocket Lab), and Caffeinated Capital (primary backers of Boom Aerospace), among others. The other $11 million was raised in a prior seed round.

Asparouhov said that the in-space factories will produce “high-value market products such as fiber optics cables, pharmaceuticals, and semiconductors,” although declined to say exactly what will be produced in the initial missions. All of the materials mentioned have been shown to have significantly higher performance and better properties when manufactured in microgravity.

Varda’s Space Factory will consist of three modules – one of them being Rocket Lab’s Photon spacecraft. In August, the company announced that it had signed a deal with Rocket Lab to procure three Photon spacecraft to support their in-space factories.

Photon will provide communications, power, and attitude control to Varda’s two internally-developed modules – the Manufacturing and Re-entry Modules. As their names suggest, these modules will manufacture the commodities and bring them safely down to Earth, respectively. Together weighing just around 120 kilograms, all three modules will be integrated on the ground and launch together on a rideshare mission.

The second Photon satellite, “Pathstone”, being integrated into the fairing ahead of the “They Go Up So Fast” Electron mission in March 2021. Credit: Rocket Lab.

Rocket Lab will deliver the first Photon Spacecraft for Varda in the first quarter of 2023, with the second spacecraft expected in late 2023 and the third in 2024. There’s also an option for Varda to procure a fourth Photon spacecraft in the future.

“The Varda team is undertaking ground-breaking work that really opens up new possibilities and markets for in-space manufacturing and we couldn’t be more excited to make their mission possible with Photon,” said Rocket Lab founder and CEO Peter Beck.

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  • “Photon enables our customers to unlock the full potential of space. It removes a massive barrier to the growing small satellite market by delivering our customers a versatile and configurable spacecraft platform that they don’t need to build themselves. Our customers get to orbit faster and can focus purely on their mission while there, rather than worrying about developing and operating a spacecraft.”

    “We are excited to work with Rocket Lab. Photon is a great fit for our mission and their team has displayed significant engineering rigor. Working with them will allow us to deliver on our aggressive schedule and tight budget. We are one step closer to delivering valuable materials to our clients here on Earth,” said Will Bruey, CEO and Co-Founder of Varda Space.

    When asked about the progress made on the hardware, Asparouhov said, “Our chief scientist has sent several of these modules up to the International Space Station before, so this hardware has not only been built before but also has flown and tested in the ISS.”

    “This is definitely not just a theoretical plan, this is real hardware,” he added.

    The module which Asparouhov is referring to is Physical Optics Corporation’s Orbital Fiber Optic Production Module which was launched to the ISS onboard SpaceX’s 17th Commercial Resupply Services (CRS-17) Mission in 2019.

    The aim of the experiment was to try to produce cleaner fibers in the microgravity environment. Since optic fibers are used for applications like data and power transmission, defects in the fiber can lead to loss of data or power. Therefore, having cleaner fibers leads to smoother operations.

    ZBLAN produced in microgravity (left) and ZBLAN produced in normal gravity (right). Image Credit: NASA

    The experiment produced ZBLAN, an optic fiber made of fluoride salts of Zirconium (Zr), Barium (Ba), Lanthanum (La), and Sodium (Na) (hence the name). When produced on Earth, it is prone to defects that occur during the solidification of the optic fibers. This happens due to the non-uniform distribution of the various chemical components within the fiber and leads to the formation of micro-crystals.

    Although this happens for any silicon dioxide-based optic fiber, the effect in ZBLAN is more pronounced due to zirconium, barium, and lanthanum being denser than aluminum and sodium, causing the boundary layers to appear in the microstructure of a material.

    Research on the ISS has shown the microgravity minimizes this effect, making it possible for ZBLAN to be used in numerous commercial applications due to significantly reduced optical loss. Estimates from the study by the ISS National Lab have shown that 2,000 kilometers of ZBLAN could have the same optical loss as 10 kilometers of silica fiber, the most used optic fiber. This amounts to over 20 times better performance due to lower defect rates.

    Once the product is manufactured, it has to land back on Earth safely – and that’s the objective of the re-entry module. The company aims to return over 100 kilograms of manufactured cargo to Earth.

    “[SpaceX’s Crew] Dragon is sort of a gold-plated Limo designed to keep humans very comfortable, [whereas] we’re sort of building the delivery van for space. It’ll be much cheaper and can handle much more Gs,” said Asparouhov.

    Photon’s 3D printed Curie engine will place Varda’s re-entry capsule on a return trajectory to Earth. The capsule re-enters the atmosphere over the United States and will touch down using parachutes on land instead of the ocean to keep the costs down. This also means the manufacturing modules, at least for the first couple of missions, will be single-use.

    Rocket Lab’s Kick Stage – the basis of the Photon satellite bus – with the small Curie engine visible in the center. Credit: Rocket Lab

    “For the first few missions, we are developing what we call it as Disposable Space Factories. The Photon and the factory will burn up but the materials will survive. That’s just to keep the technology as simple as possible.”

    The company plans to develop rendezvous and docking capability as soon as the business scales up.

    “The future is showing that we can send the materials and the factory up to the space for 1 million dollars and we can make a million and one dollars of profit. [T]he moment that happens, we [will] turn around like SpaceX and start producing these factories every single day and make them larger and larger, where initially, rather than having something the size of the Photon, we have something the size of a school bus, and eventually something the size of the ISS, or even ten times the ISS.”

    (Lead photo credit: Rocket Lab)

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