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Science

NASA’s Delayed Psyche Launch Presents Major Headache for Ride-Along Mission

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Artist’s conception of the twin Janus probes.
Image: Lockheed Martin

A software glitch has caused the delay of Psyche, a NASA mission to explore a metal-rich asteroid. Two small probes are being included in the launch, but the postponement means they might not be able to rendezvous with their respective target asteroids.

Psyche, a probe designed to explore the unusual metal-rich asteroid 16 Psyche, is currently undergoing preparations at Kennedy Space Center in Florida. Mission engineers recently spotted an anomaly that resulted in the launch delay.

“An issue is preventing confirmation that the software controlling the spacecraft is functioning as planned,” NASA announced in a May 24 press release. “The team is working to identify and correct the issue. To allow more time for this work, the launch period is being updated to no earlier than Sept. 20, 2022, pending range availability.”

The Psyche launch was supposed to happen in early August, but this small delay is causing a huge problem for planners with the Janus mission—a project to explore two unrelated binary asteroids. The twin probes are joining Psyche for the same SpaceX Falcon Heavy launch, but the delay means the mission won’t unfold as planned, as Dan Scheeres, the principal investigator of the project and an astronomer at the University of Colorado, explained at a session of NASA’s Small Bodies Assessment Group (SBAG) on Wednesday.

The Janus project is one of three planned missions under NASA’s Small Innovative Missions for Planetary Exploration (SIMPLEx-2) program, the other two being Escape and Plasma Acceleration and Dynamics Explorers (EscaPADE) and Lunar Trailblazer. For the $55 million mission, the suitcase-sized twin Janus spacecraft were designed to rendezvous with two pairs of binary asteroids, designated 1996 FG3 and 1991 VH.

Scheeres and his colleagues are hoping to study the complex orbital dynamics of the binary asteroids and create accurate models of the two systems, which they would do using a suite of cameras mounted onto the probes. By studying the asteroids from up-close, scientists will gain an improved understanding of the early solar system and acquire important insights that could improve planetary defense strategies against threatening near-Earth objects.

“The Janus mission, as conceived of and proposed to NASA, will give us information on how rubble pile asteroids evolve over time,” Scheeres explained to me in an email. “There are fundamental questions about how small, weakly bound rubble piles change over time, which has implications for a range of phenomena in the solar system—ranging from the protoplanetary disk to planetary rings to the after-effects of catastrophic disruptions.”

The Janus mission, or at least the original iteration of the mission, was to provide new data about these processes and properties. Scheeres said a modified mission could still address these questions, but at reduced resolutions.

Under the original mission parameters, the Janus probes were scheduled to perform a series of Earth flybys to meet up with the asteroids in four years, but Scheeres said the delayed launch means these critical flybys are no longer possible. “Our spacecraft were designed to be launched during August—it allowed us to be properly timed to get to our target asteroids,” Scheeres wrote. “The slip into September mostly makes this timing not feasible, except for a few days.” That said, there “are launch days when we will be able to flyby our original targets,” he told Gizmodo, but “most of the days we cannot reach them,” adding that the best-case scenario “would be to launch on those days we can get there.”

Scheeres and his colleagues are in the midst of locating other asteroids that are “scientifically interesting which we could reach on other days of the launch period,” he said. “We would just need to refocus our science goals.” One potential target, 1996 FG3, could be reached by both Janus probes should Psyche launch between October 7 and 10, according to SpaceNews. But as a rideshare mission, the team has “no ability to influence the launch dates or the targeting of the launch vehicle, and that arises from our status as a rideshare,” Scheeres pointed out at the SBAG meeting.

Such is the fate of ridesharers, who must stand by and watch situations unfold outside of their control. “It is frustrating, of course,” he told me. “However, these are the rules for rideshares, so it’s not like we didn’t know that this might happen.” Indeed, hitching a ride atop rockets makes low-cost missions to space possible, but it’s not without risks. Speaking to the SBAG meeting attendees, Scheeres said rideshare partners should have their voices heard, adding that some considerations should be made “for small adjustments to launch dates.”

As for pulling out of the Psyche mission and finding a new launch provider, Scheeres says that’s not being considered. He said no known future launch can accommodate and meet the needs of the Janus rideshare mission. That’s unless someone is willing to fund an independent launch, which doesn’t appear to be in the cards. Space is hard, as the saying goes, but in this case it’s getting to space on time that’s proving to be the issue.

More: NASA’s Latest Plan to Fix Trojan Spacecraft’s Unlatched Solar Array Shows Signs of Promise.

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NASA’s Europa Clipper spacecraft takes big step toward 2024 launch

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NASA’s Europa Clipper mission is one step closer to starting its journey to Jupiter’s icy moon.

The main body of Europa Clipper is an aluminum cylinder that clocks in at 10 feet (3 meters) tall and 5 feet (1.5 m) wide. Fitted out with integrated electronics, cabling and propulsion system, the spacecraft body arrived at NASA’s Jet Propulsion Laboratory (JPL) in southern California in early June.

“It’s an exciting time for the whole project team and a huge milestone,” Jordan Evans, the mission’s project manager at JPL, said in a statement (opens in new tab). “This delivery brings us one step closer to launch and the Europa Clipper science investigation.”

Photos: Europa, mysterious icy moon of Jupiter

Engineers and technicians will now work on the assembly of Europa Clipper — including integrating the mission’s nine science instruments — to prepare the spacecraft for launch on a SpaceX Falcon Heavy rocket in October 2024.

The Europa Clipper, named for the three-masted, ocean-going merchant ships of the 19th century, plans to conduct nearly 50 flybys of Europa, an icy moon of Jupiter that scientists believe has an internal ocean containing twice as much water as Earth’s oceans combined. 

Scheduled to arrive in the Jupiter system in 2030, the spacecraft will use its suite of instruments to gather data about Europa’s atmosphere, surface and interior to begin to answer questions about the moon’s habitability. 

Europa Clipper will also scout for potential water plumes venting samples of the theorized subsurface ocean out through Europa’s fractured and crisscrossed crust. 

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‘Time crystals’ work around laws of physics to offer new era of quantum computing

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The connecting of two “time crystals” in a superfluid of helium-3 barely one-ten-thousandth of a degree above absolute zero could be a huge step toward a new kind of quantum computer.

Time crystals are bizarre structures of atoms, the existence of which was only predicted as recently as 2012, with experimental proof following a few years later. In a normal crystal, such as diamond or salt, the atoms are arranged in a regularly repeating spatial pattern — a lattice or similar framework. And like most materials, when the atoms are in their ground state — their lowest possible energy level — they stop jiggling. 

Time crystals, on the other hand, consist of atoms that repeat in time rather than in space, oscillating back and forth, or spinning, even in their ground state. They can maintain this motion perpetually, without requiring an input of energy or losing energy in the process.

Related: Otherworldly ‘time crystal’ made inside Google quantum computer could change physics forever

In doing so, these time crystals can defy a concept known as entropy. The second law of thermodynamics describes entropy as how any system grows more disordered over time. As an example, consider the orbits of the planets around the sun. For simplicity, we imagine them moving in clockwork order, always arriving back at the same place at the same time in their respective orbits. In reality, however, things are messy: The gravity of the other planets, or passing stars, can tug and pull on the planets, making subtle changes to their orbits. 

Hence, the orbits of the planets are inherently chaotic. A small change to one can potentially have big repercussions for all of them. The system becomes disordered over time — the entropy of the system increases.

Time crystals can negate the effects of entropy because of a quantum-mechanical principle known as “many object localization.” If a force is felt by one atom in the time crystal, it affects only that atom. Therefore, the change is considered localized rather than global (throughout the system). As a result, the system does not become chaotic and allows the repeating oscillations to continue, theoretically, in perpetuity.

“Everyone knows that perpetual motion machines are impossible,” Samuli Autti, a research fellow and lecturer in physics at Lancaster University in the United Kingdom, said in a statement. “However, in quantum physics, perpetual motion is okay as long as we keep our eyes closed.”

Autti, who led the research, is referring to the Heisenberg uncertainty principle, which alludes to how, when a quantum system is observed and measured, its quantum wave function collapses. Because of their quantum mechanical nature, time crystals can operate at 100% efficiency only when fully isolated from their environment. This requirement limits the amount of time they can be observed until they completely break down as a result of wave-function collapse.

However, Autti’s team succeeded in connecting two time crystals by cooling a quantity of helium-3,  an isotope of helium. Helium-3 is special because, when cooled to a fraction above absolute zero (minus 459.67 degrees Fahrenheit, or minus 273 degrees Celsius), the isotope becomes a superfluid, which not many materials can do. In a superfluid, there is zero viscosity, so no kinetic energy is lost through friction, thus allowing motions — such as those of the atoms in a time crystal — to continue indefinitely. 

Autti’s team, working at Aalto University in Finland, then manipulated the helium-3 atoms to create two time crystals that interacted with each other. Furthermore, they observed this time-crystal pairing for a record amount of time, about 1,000 seconds (nearly 17 minutes), equating to billions of periods of oscillating or spinning motion of the atoms, before the time crystals’ wave function decayed.

“It turns out, putting two of them together works beautifully,” Autti said.

The findings create a promising line of research for developing a fully functional quantum computer. Whereas the bits of a normal computer are binary — 1s or 0s, on or off — the processing rate of quantum computers is much faster because they utilize ‘qubits,’ which can be 1 and 0, on and off at the same time. One way to build a quantum computer would be to link myriad time crystals, each one designed to act as a qubit. Therefore, this first experiment to link two time crystals has created the basic building block of a quantum computer. 

Previous experiments have already shown that some time crystals can operate at room temperature, rather than needing to be cooled to nearly absolute zero, making their construction even easier. The next task, Autti’s team said, is to demonstrate that logic gate operations, which are functions that allow a computer to process information, can operate between two or more time crystals.

The research was published June 2 in the journal Nature Communications (opens in new tab).

Follow Keith Cooper on Twitter @21stCenturySETI. Follow us on Twitter @Spacedotcom and on Facebook.



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Science

New Comprehensive Map Ties Every Human Gene to Its Function

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Data for a new gene-function map are available for other scientists to use. “It’s a big resource in the way the human genome is a big resource, in that you can go in and do discovery-based research,” says Professor Jonathan Weissman.

Scientists used their single-cell sequencing tool Perturb-seq on every expressed gene in the human genome, linking each to its job in the cell.

Genetics research has advanced rapidly over the last few decades. For example, just a few months ago scientists announced the first complete, gap-free human genome sequencing. Now researchers have advanced again, creating the first comprehensive functional map of genes that are expressed in human cells.

The Human Genome Project was an ambitious initiative to sequence every piece of human

CRISPR, which stands for clustered regularly-interspaced short palindromic repeats, a genome editing tool invented in 2009 made it easier than ever to edit DNA. It is easier, faster, less expensive, and more accurate than previous genetic editing methods.

The screen allowed the researchers to delve into diverse biological questions. They used it to explore the cellular effects of genes with unknown functions, to investigate the response of mitochondria to stress, and to screen for genes that cause chromosomes to be lost or gained, a phenotype that has proved difficult to study in the past. “I think this dataset is going to enable all sorts of analyses that we haven’t even thought up yet by people who come from other parts of biology, and suddenly they just have this available to draw on,” says former Weissman Lab postdoc Tom Norman, a co-senior author of the paper.

Pioneering Perturb-seq

The project takes advantage of the Perturb-seq approach that makes it possible to follow the impact of turning on or off genes with unprecedented depth. This method was first published in 2016 by a group of researchers including Weissman and fellow MIT professor Aviv Regev, but could only be used on small sets of genes and at great expense.

The massive Perturb-seq map was made possible by foundational work from Joseph Replogle, an MD-PhD student in Weissman’s lab and co-first author of the present paper. Replogle, in collaboration with Norman, who now leads a lab at Memorial Sloan Kettering Cancer Center; Britt Adamson, an assistant professor in the Department of Molecular Biology at

Since their initial proof-of-concept paper, Weissman, Regev, and others have used this sequencing method on smaller scales. For example, the researchers used Perturb-seq in 2021 to explore how human and viral genes interact over the course of an infection with HCMV, a common herpesvirus.

In the new study, Replogle and collaborators including Reuben Saunders, a graduate student in Weissman’s lab and co-first author of the paper, scaled up the method to the entire genome. Using human blood cancer cell lines as well noncancerous cells derived from the retina, he performed Perturb-seq across more than 2.5 million cells, and used the data to build a comprehensive map tying genotypes to phenotypes.

Delving into the data

Upon completing the screen, the researchers decided to put their new dataset to use and examine a few biological questions. “The advantage of Perturb-seq is it lets you get a big dataset in an unbiased way,” says Tom Norman. “No one knows entirely what the limits are of what you can get out of that kind of dataset. Now, the question is, what do you actually do with it?”

The first, most obvious application was to look into genes with unknown functions. Because the screen also read out phenotypes of many known genes, the researchers could use the data to compare unknown genes to known ones and look for similar transcriptional outcomes, which could suggest the gene products worked together as part of a larger complex.

The mutation of one gene called C7orf26 in particular stood out. Researchers noticed that genes whose removal led to a similar phenotype were part of a protein complex called Integrator that played a role in creating small nuclear RNAs. The Integrator complex is made up of many smaller subunits — previous studies had suggested 14 individual proteins — and the researchers were able to confirm that C7orf26 made up a 15th component of the complex.

They also discovered that the 15 subunits worked together in smaller modules to perform specific functions within the Integrator complex. “Absent this thousand-foot-high view of the situation, it was not so clear that these different modules were so functionally distinct,” says Saunders.

Another perk of Perturb-seq is that because the assay focuses on single cells, the researchers could use the data to look at more complex phenotypes that become muddied when they are studied together with data from other cells. “We often take all the cells where ‘gene X’ is knocked down and average them together to look at how they changed,” Weissman says. “But sometimes when you knock down a gene, different cells that are losing that same gene behave differently, and that behavior may be missed by the average.”

The researchers found that a subset of genes whose removal led to different outcomes from cell to cell were responsible for chromosome segregation. Their removal was causing cells to lose a chromosome or pick up an extra one, a condition known as aneuploidy. “You couldn’t predict what the transcriptional response to losing this gene was because it depended on the secondary effect of what chromosome you gained or lost,” Weissman says. “We realized we could then turn this around and create this composite phenotype looking for signatures of chromosomes being gained and lost. In this way, we’ve done the first genome-wide screen for factors that are required for the correct segregation of DNA.”

“I think the aneuploidy study is the most interesting application of this data so far,” Norman says. “It captures a phenotype that you can only get using a single-cell readout. You can’t go after it any other way.”

The researchers also used their dataset to study how mitochondria responded to stress. Mitochondria, which evolved from free-living bacteria, carry 13 genes in their genomes. Within the nuclear DNA, around 1,000 genes are somehow related to mitochondrial function. “People have been interested for a long time in how nuclear and mitochondrial DNA are coordinated and regulated in different cellular conditions, especially when a cell is stressed,” Replogle says.

The researchers found that when they perturbed different mitochondria-related genes, the nuclear genome responded similarly to many different genetic changes. However, the mitochondrial genome responses were much more variable. 

“There’s still an open question of why mitochondria still have their own DNA,” said Replogle. “A big-picture takeaway from our work is that one benefit of having a separate mitochondrial genome might be having localized or very specific genetic regulation in response to different stressors.”

“If you have one mitochondria that’s broken, and another one that is broken in a different way, those mitochondria could be responding differentially,” Weissman says.

In the future, the researchers hope to use Perturb-seq on different types of cells besides the cancer cell line they started in. They also hope to continue to explore their map of gene functions, and hope others will do the same. “This really is the culmination of many years of work by the authors and other collaborators, and I’m really pleased to see it continue to succeed and expand,” says Norman.

Reference: “Mapping information-rich genotype-phenotype landscapes with genome-scale Perturb-seq” by Joseph M. Replogle, Reuben A. Saunders, Angela N. Pogson, Jeffrey A. Hussmann, Alexander Lenail, Alina Guna, Lauren Mascibroda, Eric J. Wagner, Karen Adelman, Gila Lithwick-Yanai, Nika Iremadze, Florian Oberstrass, Doron Lipson, Jessica L. Bonnar, Marco Jost, Thomas M. Norman and Jonathan S. Weissman, 9 June 2022, Cell.
DOI: 10.1016/j.cell.2022.05.013



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