Category: Cosmic Space

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Cosmic Space

Billionaire boosts missions to the clouds of Venus

Concept: European Venus Explorer
Artwork shows the proposed European Venus Explorer floating amid Venus' clouds. (ESA / EVE Team / Tibor Balint)

Breakthrough Initiatives, a space science program founded by Russian-Israeli tech billionaire Yuri Milner, says it’s funding a study that will follow up on this week’s controversial findings about the potential for life in the clouds of Venus.

The study could lead to a range of concepts for space missions to Venus, adding to several proposals that are already under consideration by NASA and other space agencies.

MIT planetary scientist Sara Seager, one of the authors of the research paper published this week in Nature Astronomy, is leading the Breakthrough Initiatives’ project as principal investigator. There’s already a website devoted to the study, VenusCloudLife.com, and a virtual kickoff meeting is set for Sept. 18, she told me today.

Among other leaders of the Venus Life Finder Mission Concept Study are MIT’s Janusz Petkowski and William Bains, two of the co-authors of the Nature Astronomy study; Georgia Tech’s Chris Carr; Caltech’s Bethany Ehlmann; the Planetary Science Institute’s David Grinspoon; and Pete Klupar, chief engineer of the Breakthrough Initiatives.

The study group will follow up on findings suggesting that a biomarker known as phosphine or PH3 is present within a potentially habitable band of clouds surrounding the hellishly hot planet. Phosphine can be produced by non-biological processes, but the team behind this week’s published findings said they could not explain how it was present at the detected levels unless biology was involved.

For decades, scientists have debated whether life might exist in the clouds of Venus — specifically, within a layer that’s between 30 and 40 miles above the surface. That’s the only place in the planet’s environment where water could exist in liquid form, and even there, the atmosphere contains droplets of highly corrosive sulfuric acid. Finding life is a long shot, but it’s a shot Milner thinks is worth taking.

“Finding life anywhere beyond Earth would be truly momentous,” Milner said in a news release. “And if there’s a non-negligible chance that it’s right next door on Venus, exploring that possibility is an urgent priority for our civilization.”

Breakthrough Initiatives is already funding several $100 million space projects — including an expanded search for radio signals from extraterrestrial civilizations and a project to send fleets of life-seeking nanoprobes through the Alpha Centauri star system. Milner has also provided resources for exoplanet studies and a potential mission to Enceladus, an icy moon of Saturn that may harbor life.

The budget for the Venus mission concept study is nowhere near $100 million. Seager said via email that the study will get a “few hundred thousand” dollars in support from the Breakthrough Initiatives, and that “we aim to have ‘in-kind’ contributions, i.e., work contributed, that push that number much higher.”

“It’s not really a huge amount for mission studies, but we are leveraging the formal study to get lots of people from the community to contribute,” she explained during a separate phone conversation. “We’ve got scientists, engineers, and we also have some industrial partners joining … but the study is just starting.”

One of those partners is Los Angeles-based Rocket Lab, which has already said it’s aiming to send a probe toward Venus in the 2023-2024 time frame, using its low-cost Electron rocket.

Seager said Rocket Lab’s plan would be classified as a small mission concept. Such a concept envisions having a cruise vehicle drop off a descent capsule with a few kilograms’ worth of scientific instruments. The instruments would analyze Venus’ atmospheric composition for up to 10 minutes, potentially confirming the presence of phosphine and looking for other chemical signs of life.

Medium mission concepts would involve sending an inflatable balloon to Venus on a bigger rocket as a piggyback payload. The mission would be similar to what the Soviets did in the 1980s when they sent balloon-borne instruments into the Venusian atmosphere. Those probes transmitted data for a couple of days before their batteries gave out.

Such missions could accommodate an arsenal of scientific instruments amounting to as much as 20 kilograms (44 pounds).

“They could go beyond just detecting gases,” Seager told me. “They could analyze the liquid droplets in Venus’ atmosphere. They could try to identify complex molecules, like heavier molecules of the types that are only associated with life. And we’d like to imagine having a microscope on board. We could collect droplets and concentrate them and see if there’s anything that might resemble any kinds of life.”

Large mission concepts would involve sending an orbiter as well as a long-lasting balloon platform to Venus for months of study.

Seager said she expects the Breakthrough Initiatives project to work in a collaborative fashion with other teams that have parallel proposals for missions to Venus.

Among the potential missions are DAVINCI+, which aims to send a probe through Venus’ clouds; and VERITAS, which is designed to map Venus’ geology. Those mission concepts are among four finalists  in NASA’s Discovery Program, along with concepts for missions to the Jovian moon Io and the Neptunian moon Triton. One or two of the concepts are to be selected for further funding next year.

“There is no doubt that NASA’s Science Mission Directorate will have a tough time evaluating and selecting from among these very compelling targets and missions, but I know the process will be fair and unbiased,” NASA Administrator Jim Bridenstine said this week.

But wait, there’s more: Plans for a NASA-led Venus Flagship Mission have been under discussion for years, and NASA is currently talking with the European Space Agency about an ambitious Venus mission concept called EnVision. Meanwhile, space scientists in Russia, India and China have their own ideas for missions to Venus.

A decade ago, the European Space Agency considered sending a balloon to Venus as part of a proposed mission called the European Venus Explorer, or EVE. That proposal fizzled out, but a different mission with a European connection, BepiColombo, should get a close-up look at Venus next month while on its way to Mercury.

The Oct. 15 flyby is the first of two close encounters with Venus on BepiColombo’s itinerary. During each of those flybys, the probe could use its thermal infrared spectrometer to check for signs of phosphine and anything else that could help scientists plan for future missions.

“If they have the right instrument and they can take a look at Venus, that’d be awesome,” Seager said. “It would be great to get whatever observations we can.”

Update for 9:25 a.m. PT Sept. 17: I’ve updated this report with Seager’s comments on how much support will be provided by the Breakthrough Initiatives.

Read more: David Grinspoon weighs in on Venus
Categories
Cosmic Space

Life on Venus? Future space missions could check it out

Venus
This false-color image of Venus is based on ultraviolet data from Japan's Akatsuki probe. (JAXA / ISAS / Akatsuki Project Team / CC BY 4.0)

Scientists say they’ve detected a chemical associated with biological activity within the clouds of Venus, at a height where airborne life forms could theoretically exist.

The chemical, known as PH3 or phosphine, isn’t the first biomarker to be found in Venus’ atmosphere. But the scientists say they can’t come up with a non-biological process that could produce phosphine at the levels they’re seeing.

This isn’t the smoking gun for life on Venus. Nevertheless, the latest findings — which leaked out over the weekend and were published today in Nature Astronomy — give peer-reviewed weight to an idea that once seemed almost ludicrous: the idea that microbes or other life forms may be perpetually floating in Venus’ acidic air, more than 30 miles above the planet’s searingly hot surface.

The findings are also likely to give a push to several proposed space missions that are already targeting the clouds of Venus.

“It may be that Venus, not Mars, is our best hope for a long-inhabited nearby neighbor,” David Grinspoon, a senior scientist at the Planetary Science Instutute, told me in an email.

The possibility of finding life in Venus’ clouds has been under debate for decades. The late astronomer Carl Sagan surveyed the prospects almost 60 years ago. More recently, Grinspoon and other astrobiologists have revived the case for closer study of Venus, in hopes of finding traces of microbial life in the clouds.

Grinspoon told me it’s been a tough sell. “Folks would roll their eyes at my conference talks, but I was tolerated because I did a lot of good work on other aspects of Venus, writing papers on the clouds, the surface evolution, the climate, and so forth,” he said.

It’s not hard to see why Venus has been upstaged by Mars as well as the icy moons of Jupiter and Saturn when it comes to the search for life elsewhere in the solar system. Although Venus is close to Earth’s size and mass, its average surface temperature of 900 degrees Fahrenheit is hot enough to melt lead, due to a runaway greenhouse-gas effect.

Venus’ dense, surface-obscuring atmosphere consists primarily of carbon dioxide, but it’s also laced with droplets of sulfuric acid that makes it inhospitable to most life on Earth.

Even if amped-up versions of our own planet’s acid-loving microbes were to exist on Venus, the only place astrobiologists can imagine them getting a foothold would be within a temperate band of clouds that lie between 30 and 40 miles above the surface.

Just last month, a team of scientists — including some of the co-authors of the newly published study — proposed a spore-based life cycle for aerial microbes within that cloud band.

What kind of evidence might such creatures leave behind? Researchers at the Massachusetts Institute of Technology zeroed in on phosphine — a smelly, toxic gas given off by anaerobic bacteria on Earth. MIT planetary scientist Clara Sousa-Silva thought the spectral fingerprint of phosphine would be a good biosignature to look for when advanced telescopes analyze the light reflected by planets in alien star systems.

“I was thinking really far, many parsecs away, and really not thinking literally the nearest planet to us,” she said in a news release.

The astronomers who focused in on Venus weren’t expecting to find phosphine, either. When they observed the planet using the James Clerk Maxwell Telescope in Hawaii, they expected to rule out some of the claims surrounding life on Venus.

“This was an experiment made out of pure curiosity, really — taking advantage of JCMT’s powerful technology, and thinking about future instruments,” study lead author Jane Greaves, an astronomer at Cardiff University in Wales, said in a news release.

“I thought we’d just be able to rule out extreme scenarios, like the clouds being stuffed with organisms,” she said. “When we got the first hints of phosphine in Venus’ spectrum, it was a shock!”

What’s more, the phosphine was found precisely in the band of the cloud layer that’s most hospitable to life.

The detection was confirmed with follow-up observations from the Atacama Large Millimeter Array, or ALMA, in Chile. Greaves and her team then turned to other scientists to help interpret the findings.

Researchers considered a wide range of non-biological mechanisms for putting phosphine into the Venusian atmosphere — for example, by cooking other molecules with solar radiation or lightning, or having the wind sweep up minerals from the surface, or having the phosphine expelled by volcanoes, or bringing it in from space via meteors.

Phosphine is created non-biologically at Jupiter and Saturn, due to the abundance of hydrogen and the crushing atmospheric pressure at those gas giants, but the researchers noted that such conditions don’t exist on Venus. “That particular chemistry is definitely not happening at Venus,” MIT’s William Bains said today during a news briefing.

None of the mechanisms that the researchers considered could produce the level of phosphine that the astronomers detected, which amounts to 20 molecules per billion. Their most productive non-biological scenario could make, at most, only one-ten-thousandth of the required amount.

That leaves the biological scenario as the favored explanation, unless someone else comes up with a better explanation that the research team missed.

“It’s very hard to prove a negative,” Sousa-Silva said. “Now, astronomers will think of all the ways to justify phosphine without life, and I welcome that. Please do, because we are at the end of our possibilities to show abiotic processes that can make phosphine.”

On Earth, microbes are routinely lofted into upper levels of the atmosphere and eventually drift back down. But on Venus, such organisms would be killed off if they sank too low. Such an exclusively aerial biosphere might have evolved from an earlier age when Venus was far more hospitable to life, Sousa-Silva said.

“A long time ago, Venus is thought to have oceans, and was probably habitable like Earth,” she said. “As Venus because less hospitable, life would have had to adapt, and they could now be in this narrow envelope of the atmosphere where they can still survive.”

So what’s next? Sousa-Silva and MIT’s Jason Dittman are leading an effort to confirm the phosphine findings with data from other telescopes, and map the distribution of phosphine across the Venusian atmosphere over time. If there are daily or seasonal variations, that could provide additional evidence for biological activity.

“The experiment must and will be repeated,” Grinspoon told me. “Laboratory studies will be undertaken to see how PH3 behaves in a Venus-like environment and what else could possibly produce it. But the best test, and the one I’m most excited about, is to go back to Venus and investigate the atmosphere in situ.”

Last month, a panel of scientists presented a 222-page report laying out the possibilities for a flagship mission to Venus, as part of the astronomy community’s 2020 decadal survey of science priorities.

One mission concept, advanced by Northrop Grumman, calls for sending an instrument-laden, solar-powered aircraft called VAMP into the Venusian atmosphere.

Another concept, known as DAVINCI+, is one of four proposals vying for funding through NASA’s Discovery Program. The DAVINCI+ spacecraft would map Venus and its atmosphere from orbit. It’d also drop a spherical probe through the atmosphere, all the way to the surface, to sniff out the molecules making up each layer.

“Our vision for DAVINCI+ is to send a chemistry lab and orbiter to Venus to put the planet into its appropriate context in our solar system,” principal investigator Jim Garvin, who is chief scientist at NASA’s Goddard Space Flight Center, said in a news release.

If DAVINCI+ is selected for full funding next year, Garvin and his teammates propose launching the mission in 2026.

Yet another Discovery Program finalist, the proposed VERITAS mission, would concentrate on creating three-dimensional maps of Venus’ surface features and geology. NASA is also considering a CubeSat mission to study Venus’ atmosphere.

Meanwhile, California-based Rocket Lab is making plans to send a probe to Venus within three years or so.

“I’m working very hard to put together a private mission to go to Venus in 2023,” Rocket Lab CEO Peter Beck said last month during a webcast. “We’re going to learn a lot on the way there, and we’re going to have a crack at seeing if we can discover what’s in that atmospheric zone. And who knows? You may hit the jackpot.”

MIT’s Sara Seager said she and her colleagues have been talking with Rocket Lab about putting together the scientific payload for such a mission. The requirements are challenging: Such a payload would have to weigh no more than 3 kilograms (6.6 pounds), Seager said.

Details about potential funding for Rocket Lab’s mission haven’t yet come to light, but Russian-Israeli tech billionaire Yuri Milner is known to have Venus on his short list for a privately funded mission.

Back in 1985, the twin Soviet Vega probes deployed two balloon explorers in the Venusian atmosphere. Instruments on the balloons sent back data for 46 hours before their batteries ran out. Today, Seager was asked about that mission concept and said “a balloon is certainly the best way” to study what’s in the clouds.

“We have a long list of things we’d like, actually,” she said.

Over the past 30 years, NASA, the European Space Agency and the Japan Aerospace Exploration Agency have sent probes to Venus. In light of the findings published today, Grinspoon thinks it’s high time for the next visit.

“Now that we’ve found a genuine candidate biosignature, we absolutely must go,” he said. “And even if this turns out to be a false alarm, it could be productive, in the way that the ‘Mars rock’ (ALH84001) was. That turned out — probably — to be a false alarm, but it got everyone to think about it in a fresh way and ask, ‘Why not?’ ”

Update for 8:50 a.m. PT Sept. 14: NASA’s associate administrator for science, Thomas Zurbuchen, tweeted that the findings are “intriguing” but added that NASA will defer further comment until the post-publication discussion has run its course:

Update for 1:10 p.m. PT Sept. 14: Later in the day, NASA Administrator Jim Bridenstine tweeted that “it’s time to prioritize Venus” — which will probably lift the spirits of the folks working on the aforementioned proposals for missions to Venus:

https://twitter.com/JimBridenstine/status/1305598182571810822

In addition to Greaves, Sousa-Silva, Bains and Seager, the authors of the Nature Astronomy paper, “Phosphine Gas in the Cloud Decks of Venus,” include Anita Richards, Paul Rimmer, Hideo Sagawa, David Clements, Janusz Petkowski, Sukrit Ranjan, Emily Drabek-Maunder, Helen Fraser, Annabel Cartwright, Ingo Mueller-Wodarg, Zhuchang Zhan, Per Friberg, Iain Coulson, E’lisa Lee and Jim Hoge.

Read more: David Grinspoon weighs in on Venus
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Cosmic Space

Nuclear power on the moon? It could happen by 2028

Lunar nuclear power system
An artist's concept shows a nuclear fission power system on the lunar surface. (NASA Illustration)

Nuclear energy has played a role in lunar exploration since the golden days of the Apollo moon program, when radioisotope power systems provided the wattage for scientific experiments.

Today such systems continue to power interplanetary spacecraft, ranging from the decades-old Voyager probes in interstellar space to the Perseverance rover that’s on its way to Mars. And now the U.S. Department of Energy and NASA are kicking things up a notch.

Tracey Bishop, deputy assistant secretary for nuclear infrastructure programs at the Department of Energy’s Nuclear Energy Office, provided a preview today during a virtual roundtable discussion focusing on the department’s role in space exploration.

“This summer the department, along with NASA, has initiated an activity to look at doing a demonstration for fission surface power systems on the moon in the 2027, 2028 time frame, ” Bishop said.

She said potential partners from the nuclear power industry as well as the aerospace industry showed up for a “very engaging Industry Day” last month. “We’re looking forward to issuing a request for proposals from industry sometime this fall,” Bishop said.

The lunar demonstration project would follow up on the research conducted as part of the NASA-DOE Kilopower program, which successfully demonstrated a small-scale nuclear power system in Nevada a couple of years ago.

And that’s not all: The National Nuclear Security Administration, a semi-autonomous agency within DOE, is working with the Pentagon’s Defense Advanced Research Projects Agency on a road map for developing nuclear thermal propulsion systems.

“What DARPA is trying to do is, they’re trying to have a demonstrator that will fly in the 2025 time frame,” said Kevin Greenaugh, assistant deputy administrator for strategic partnership programs.

It’s early in the process, but federal officials eventually plan to turn to industry experts for help in designing what basically would be a nuclear rocket engine, Greenaugh said.

The project — known as the Demonstration Rocket for Agile Cislunar Operations, or DRACO — would use nuclear power to heat rocket propellants to temperatures high enough to produce thrust. Such a system would be two to five times more efficient than conventional chemical propulsion, resulting in huge time savings for missions ranging from repositioning satellites to sending astronauts to Mars.

NASA and the Atomic Energy Commission tried to get a nuclear rocket called NERVA off the ground back in the 1960s.

“We did enough to understand what it was going to take, what the technical challenges are, and the fact that these [technologies] really are enabling for doing things such as certainly sending crews to Mars,” said Ralph McNutt, the chief scientist for space science at Johns Hopkins University’s Applied Physics Laboratory.

Project NERVA fizzled in the post-Apollo era, due to shrinking space budgets as well as growing safety concerns about nuclear power. But now America’s space ambitions are on the rise again, and next-generation nuclear power concepts are raising confidence that the safety concerns can be adequately addressed.

“The advanced modular reactors are certainly adaptable to be used in earthbound applications, too,” said former U.S. Rep. Robert Walker, who now heads a space policy consulting firm called moonWalker Associates. “That’s where a lot of the work is being done right now.”

Energy Secretary Dan Brouillette said following through on the concept could yield big payoffs.

“Nuclear propulsion could potentially cut the time of space travel to Mars by as much as half, which increases mission flexibility — which can be a true game changer for a Mars mission,” he said. “We’d like to get to Mars and back on ‘one tank of gas.’ That’s our goal, and that’s what we’re working for.”

Paul Dabbar, DOE’s under secretary for science, added that “it’s not just about getting to where we’re going, but it’s also about what we want to do when we get there.”

That’s where the interest in surface-based nuclear power comes to the fore. After all, if billionaires Jeff Bezos and Elon Musk envision building whole cities on the moon and on Mars, the power’s got to come from somewhere.

Eric Stallmer, president of the Commercial Spaceflight Federation, said future space settlements will almost certainly be built as public-private partnerships — with federal agencies like NASA and DOE blazing the technological trails for commercial ventures to follow.

“NASA has seen this in spades, when they did the development of resupplying cargo and crew to the ISS [International Space Station],” he said. “The government estimates that it saved between 20 and 30 billion dollars, compared to the traditional methods.”

So what will those extraterrestrial power systems look like? Will the moon go all-nuclear? Probably not, said Ben Reinke, executive director of the Department of Energy’s Office of Strategic Planning and Programs. Off-Earth settlements are more likely to rely on a mix of solar and nuclear power — plus batteries to store surplus electricity, as well as stores of hydrogen and oxygen that could be produced from ice on the moon or Mars.

“What you’re really talking about is a very small microgrid that has the same types of challenges that we have here on Earth,” he said. “You need some amount of power that would be baseload power. … And then on top of that, you would probably have some types of variable power, and a storage and distribution system that works for the proper size of that case.”

It turns out that nuclear fission isn’t the only option for energy on the moon: Reinke said lightweight, highly efficient perovskite solar cells could come into play. And who knows? Decades from now, nuclear fusion may even be part of the mix, with ample supplies of helium-3 fuel available on the lunar surface.

All of those technologies are part of the Department of Energy’s portfolio — so maybe Secretary Brouillette has a point when he says the DOE in his agency’s acronym could just as well stand for “Department of Exploration.”

Full disclosure: I served as the moderator for today’s virtual roundtable presentation, titled “Department of Exploration: Because You Can’t Get to Space Without the U.S. Department of Energy.”

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Cosmic Space

Blue Origin veterans spark space startups

Andrew Lapsa
While at Blue Origin, Andrew Lapsa won an AIAA award. Now he's the CEO of his own company. (Blue Origin via Twitter / 2017 Photo)

Amazon CEO Jeff Bezos’ Blue Origin space venture turned 20 years old this week — and although the privately held company hasn’t yet put people into space, or put a rocket into orbit, it has spawned a new generation of space startups.

One of those startups, Relativity Space, pulled up stakes in Seattle early on and moved to Southern California. Now it’s making a multimillion-dollar splash and putting the pieces in place for the first launch of its Terran rocket from Florida next year.

Relativity is also going through a leadership transition: Jordan Noone, the venture’s co-founder and chief technology officer, announced today on Twitter that he’ll step back and become an executive adviser “in preparation for starting my next venture.” Relativity’s other co-founder, Blue Origin veteran Tim Ellis, will stay on as CEO.

Other startups are in semi-stealth mode. Here are three notable Seattle-area ventures with Blue Origin connections:

Stoke Space Technologies: Incorporated last October in Renton. Co-founders are CEO Andrew Lapsa, who was responsible for all aspects of development and operation for Blue Origin’s hydrogen-fueled BE-3 and BE-3U engines; and Thomas Feldman, an engineer who played a key role in designing components for the more powerful BE-4 engine, fueled by liquefied natural gas.

Stoke’s website says the company is “building technology to seamlessly connect Earth and orbit.” In May, the company won a $225,000 SBIR Phase I grant from the National Science Foundation to work on an integrated propulsion solution for reusable rocket upper stages.

Stoke says it’ll use the NSF funding “to develop new technology enabling space launch vehicles to re-enter the atmosphere and land propulsively at a target destination for reuse.” SpaceX’s Falcon rockets and Blue Origin’s yet-to-be-built New Glenn rocket are designed with first-stage reusability in mind. Stoke is looking ahead to the next giant leap in reusable rockets.

In addition to Lapsa and Feldman, LinkedIn lists three other Stoke employees with Blue Origin experience. And they have  job openings for a lead system architect and a “Superhuman.”

Reach Space Technologies: Incorporated in February in Maple Valley. The company’s website is still password-protected, but LinkedIn lists Mike Krene, former senior propulsion engineer at Blue Origin, as founder and CEO. Krene spent a decade at Blue Origin, and before that, he dealt with propulsion systems at SpaceX and Pratt & Whitney.

The venture says it aims to “accelerate the time and reduce the cost for new launch startups to get to commercial viability, thereby growing the overall launch market.”

“Our engine systems also provide a high-value, commercially focused propulsion option for existing NewSpace and traditional launch providers,” Reach Space says on its LinkedIn page.

The company says it has between two and 10 employees, including “leading engineers with experience across many flight and development rocket engine systems.”

Starfish Space: Incorporated last November in Kent, where Blue Origin is headquartered. The co-founders are Trevor Bennett, a former flight sciences engineer at Blue Origin; and Austin Link, who spent three years at Blue Origin as a flight sciences simulation engineer. Ian Heidenberger, Starfish’s principal roboticist, was an autonomous-controls engineer at Blue Origin.

Starfish says it’s a venture-backed startup but has not yet revealed details about its investors or investments. It’s working on an “on-demand, in-space transportation service,” including a space tug that could be used to relocate, deorbit or extend the life of satellites. It’s also developing the software to support rendezvous and proximity operations — with an emphasis on electric propulsion.

Four years ago, Jeff Bezos told me his goal for Blue Origin was to build the “heavy-lifting infrastructure” for a wider space industry ecosystem, just as the U.S. Postal Service, UPS and the internet furnished the infrastructure that got Amazon off the ground. Now it looks as if Blue Origin is providing a seedbed for that ecosystem, even before the company has fully occupied its own niche in the marketplace.

Correction for 12:35 a.m. PT Sept. 10: We’ve fixed the spelling of Ian Heidenberger’s name. Hat tip to Isaac Alexander.

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Cosmic Space

Black hole crash creates LIGO’s biggest ‘bang’

Black hole merger
An artist's conception shows two black holes spiraling in to create an even bigger black hole. (Image credit: Mark Myers / OzGrav)

Scientists say the merger of two black holes that occurred when the universe was half its current age has created the most massive source of gravitational waves ever observed.

After traveling billions of light-years, the disturbance in spacetime was picked up on May 21, 2019, by the Laser Interferometer Gravitational-Wave Observatory, also known as LIGO, and the Virgo gravitational-wave detector in Italy. The unusual event and its implications are described in papers published today by Physical Review Letters and the Astrophysical Journal Letters.

“This doesn’t look much like a chirp, which is what we typically detect,” Nelson Christensen, an astrophysicist at the French National Center for Scientific Research, said in a news release. “This is more like something that goes ‘bang,’ and it’s the most massive signal LIGO and Virgo have seen.”

Christensen and his colleagues say the signal, known as GW190521, appears to have come from the violent collision of two spinning black holes that were about 85 and 66 times as massive as our sun.

The merger created an even bigger black hole that’s about 142 times as massive as the sun. It also released the equivalent of eight solar masses in the form of gravitational-wave energy, in accordance with Albert Einstein’s E=mc2 formula, the scientists said.

GW190521 not only ranks as the biggest bang recorded since LIGO made its initial, Nobel-winning gravitational-wave detection in 2015. It also counts as LIGO’s first detection of a mysterious object known as an intermediate-mass black hole.

For decades, physicists have been fleshing out their theories regarding the nature and origin of black holes — concentrations of matter so massive and compact that nothing, not even light, can escape their gravitational grip.

Some black holes are thought to be created when stars up to 130 times as massive as our sun run out of their fusion fuel and collapse inward, producing black holes as big as 65 solar masses. There are also scenarios in which stars that weigh more than 200 solar masses can collapse into black holes in the range of 120 solar masses.

A completely different process leads to the creation of monster black holes at the centers of galaxies (including our own galaxy). Such supermassive black holes are at least 1,000 times as massive as the sun.

Not that long ago, scientists thought the physics behind gravitational collapse ruled out the creation of black holes between 65 and 120 solar masses. Instead, the collapse of midsize stars was thought to produce instability through the creation of electron-antielectron pairs — and as a result, the stars were supposed to blow themselves completely apart.

Now, the fact that one of the black holes involved in last year’s smashup was measured at 85 solar masses is complicating claims for the existence of a pair instability mass gap.

“The fact that we’re seeing a black hole in this mass gap will make a lot of astrophysicists scratch their heads and try to figure out how these black holes are made,” said Christensen, who is the director of the Artemis Laboratory at the Nice Observatory in France.

The authors of the paper published in the Astrophysical Journal Letters have already come up with one possibility: Perhaps the midsize black hole was not directly produced by a stellar collapse, but instead by an earlier merger of smaller black holes — just the sort of merger that LIGO and Virgo have been detecting over the past five years.

“This event opens more questions than in provides answers,” said Caltech physicist Alan Weinstein, a member of the LIGO collaboration. “From the perspective of discovery and physics, it’s a very exciting thing.”

Weinstein cautioned that there’s still some uncertainty about the current explanation for GW190521.

“Since we first turned on LIGO, everything we’ve observed with confidence has been a collision of black holes or neutron stars,” he said. “This is the one event where our analysis allows the possibility that this event is not such a collision.  Although this event is consistent with being from an exceptionally massive binary black hole merger, and alternative explanations are disfavored, it is pushing the boundaries of our confidence. And that potentially makes it extremely exciting.”

Further observations from LIGO and Virgo could turn up something completely new in the gravitational-wave menagerie — for example, evidence for the creation of primordial cosmic strings.

The LIGO project is funded by the National Science Foundation and operated by Caltech and MIT. It relies on two gravitational-wave detectors that have been built at Hanford, Wash., and at Livingston, La., with about 2,000 miles of separation to provide a double-check on the detectors’ results.

Each detector consists of an L-shaped network of tunnels, measuring 2.5 miles on a side, with laser beams reflected back and forth within the tunnels. Gravitational waves from far-off cataclysms disturb the fabric of spacetime ever so slightly — but the detectors are sensitive enough to pick up such disturbances to within the width of a proton.

Europe’s Virgo detector, designed according to a similar scheme, provides further verification for LIGO’s gravitational-wave data and makes it easier to triangulate on the sources of the waves.

In the case of GW190521, the waves are thought to have been thrown off by a source that’s now roughly 17 billion light-years (5 gigaparsecs) away from us — at a time when the universe was about half its current age of 13.8 billion years. That makes it one of the most distant gravitational-wave sources detected so far.

Because light travels at a finite speed, it may seem counterintuitive for a signal that was sent out 7 billion years ago to be received from an object that’s 17 billion light-years away.

But in an email exchange, Weinstein told me there’s a relatively simple explanation for the seeming mismatch. “The universe has been expanding since the gravitational waves were emitted,” he wrote. “So physical distances are tricky to interpret in an expanding universe, and must be treated with care.”

Categories
Cosmic Space

Pentagon awards $282 million for satellite constellation

Linked satellites
Artwork shows how satellites will be woven together into a mesh network with the aid of optical cross-links. (SDA / DOD Illustration)

Lockheed Martin and York Space Systems will share $281.6 million in contracts from the Pentagon’s Space Development Agency to build the first 20 satellites for a new military data network with global reach.

The network will be capable of sending targeting data directly from a remote-sensing satellite in space to a weapons platform on the ground, making use of laser communications between satellites in low Earth orbit. By the late 2020s, the system is expected to play a key role in countering emerging threats such as hypersonic attack vehicles.

The National Defense Space Architecture is the first major project for the Space Development Agency, which was created last year to foster military technologies on the high frontier.

“This is a very important step toward building the National Defense Space Architecture. It represents one of the Space Development Agency’s first major contract activities, and it might also highlight the importance of SDA — its ability to quickly obligate appropriate funds and execute toward their mission,” Mark Lewis, acting deputy under secretary of defense for research and engineering, told reporters.

“As the Netflix ‘Space Force’ series likes to say, space is hard,” he said. “Space is hard, but sometimes we make it harder than it has to be. The SDA is showing us that sometimes we don’t need to make it that hard.”

The two Colorado-based companies receiving awards today will build 10 satellites each for the first phase of the project, known as Tranche 0. Lockheed Martin is due to receive $187,542,641 under the terms of a firm, fixed-price contract. York Space Systems, a relative newcomer in the satellite industry, will receive $94,036,666.

Tranch 0’s data-transport-layer satellites are to be launched no later than September 2022, with a “capstone” demonstration of the mesh network’s capabilities planned in late 2022 or early 2023.

SDA Director Derek Tournear said today’s contracts represent the first step for a network that will comprise hundreds of satellites by 2026.

“We’re pushing on completely developing a new architecture that breaks the old model,” Tournear said. A big part of the new model will involve relying on commercial providers and “spiral development” to add innovations as the constellation is built out, he said.

“We’ll see this as an era of new space, basically showing the concept that you can utilize commoditized components in a very rapid manner to meet military utility and military specifications,” Tournear said.

Each set of 10 spacecraft will include seven equipped with the hardware for four laser-enabled optical cross-links between satellites. The other three satellites will have two optical cross-links, plus a standard Link 16 transceiver to communicate with ground installations.

Tournear said the satellites will be interoperable with other commercial and military space assets — including remote-sensing spacecraft, military communication satellites and commercial telecom constellations. He told me his team is talking with ventures including SpaceX, which already has launched hundreds of satellites in low Earth orbit for its Starlink broadband network. (Other parts of the U.S. military are testing Starlink’s capabilities for military applications.)

The Space Development Agency says the satellites will be sent into orbits ranging from 600 to 1,200 kilometers (370 to 740 miles) in altitude. That’s higher than the altitude that was recommended last week for minimizing negative effects on astronomical observations. But Tournear noted that the Tranch 0 satellites will be smaller and less numerous than, say, Starlink satellites.

The first batches of satellites won’t make use of the brightness-reducing measures that SpaceX has been implementing, he said. But there’ll be many more satellites to come.

“We’re going to be building out roughly one satellite a week for each of the [orbital] layers … and then launching them out on a cadence that allows us to replenish and add new capabilities that we’re going to be soliciting,” Tournear said.

In its contract announcement, the Department of Defense said the work of building the Tranche 0 satellites would be done in seven U.S. states plus Germany, Canada and Spain.

About 3.3% of York’s work is to be performed in Bothell, Wash., the Pentagon said. Bothell-based Tethers Unlimited has partnered with York previously, and Tethers CEO Bob Hoyt told me that his company has been in on some of York’s proposals for the National Defense Space Architecture. But he said he hasn’t yet heard whether Tethers Unlimited will play a role in the contract awarded today.

Categories
Cosmic Space

How astronomers aim to cope with satellites’ glare

Satellites in orbit
Thousands of satellites are due to go into low Earth orbit. Caveat: Satellites not shown to scale. (NOIRLab / NSF / AURA / P. Marenfeld)

If the vision of putting thousands of satellites into low Earth orbit to provide global broadband internet access comes anywhere close to fruition, there’s no way to avoid a negative impact on astronomy.

But the magnitude of the damage depends on what satellite operators, policymakers, professional researchers and amateur astronomers do.

That’s the bottom line from a report issued today by the American Astronomical Society and the National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory, or NOIRLab.

The report recaps findings from a virtual workshop conducted from June 29 to July 2. The workshop brought together more than 250 stakeholders in the satellite-vs.-sky controversy, including representatives from Amazon, OneWeb and SpaceX.

“Our team at the AAS was enthusiastic to partner with NOIRLab and bring representatives of the astronomical and satellite communities together for a very fruitful exchange of ideas,” AAS President Paula Szkody, an astronomer at the University of Washington, said in a news release. “Even though we’re still at an early stage of understanding and addressing the threats posed to astronomy by large satellite constellations, we have made good progress and have plenty of reasons to hope for a positive outcome.”

SpaceX has already launched more than 650 of its Starlink satellites, with the aim of providing broadband access for the billions of people who are currently underserved. OneWeb, which was recently acquired by an Indian-British consortium after going through bankruptcy proceedings, has launched 74 satellites. And Amazon’s Project Kuiper is making plans for its own 3,236-satellite constellation.

If those three ventures follow through on their regulatory filings, tens of thousands of satellites could be in low Earth orbit within a decade — boosting the current tally by an order of magnitude.

SpaceX’s Starlink spacecraft are built at the company’s facility in Redmond, Wash., which is also where Amazon is putting its research and development center for Project Kuiper.

Most astronomers paid little attention to the potential threat to the night sky until SpaceX launched its first full batch of 60 Starlink satellites in May 2019. They were shocked to see how the trains of passing satellites disrupted astronomical observations.

Since then, SpaceX’s representatives have been talking with astronomers about how to mitigate the effect of the satellites’ reflective glare, which is at its worst just after sunset and just before sunrise.

“SpaceX has set an excellent example of a collaborative effort between astronomy and industry to manage this problem, and we certainly hope to see other operators following suit,” Jeff Hall, an astronomer from Arizona’s Lowell Observatory who heads AAS’ committee on light pollution, told reporters today during a teleconference.

As an experiment, SpaceX reduced the reflectivity of one of the Starlink satellites launched in January. Lori Allen of NSF’s NOIRLab said that “DarkSat” was about half as bright as the standard satellites, representing a reduction in visual magnitude from 5.2 to 6.2. (The higher the magnitude, the dimmer the object on a logarithmic scale.)

SpaceX is continuing to work on the reflectivity issue, and its most recent Starlink launch sent up 57 satellites equipped with specially designed sun visors. Allen said it was too early to determine how much the visors cut down on the glare from those satellites — in part because the coronavirus pandemic has forced astronomers to cut back on their observing time.

Based on observations as well as simulations, the report says mega-constellation ventures should reduce the reflectivity of their satellites to make them fainter than a 7th-magnitude star. (Such stars are the faintest objects that can be seen with the naked eye in dark skies.)

The report also calls for satellites in low Earth orbit to fly no higher than 600 kilometers (373 miles).

At altitudes higher than that, the satellites would catch the glint of the sun throughout the night in summer skies. “There’s no place to hide in the middle of the night from such a satellite constellation,” said Tony Tyson, an astronomer at the University of California at Davis who is also chief scientist for the Vera Rubin Observatory in Chile.

That’s a big problem for OneWeb, which is seeking to put tens of thousands of satellites in 1,200-kilometer-high orbits. It’s less of a problem for SpaceX (which is reserving orbital spots at altitudes between 328 and 614 kilometers) and for Amazon’s Project Kuiper (which is targeting heights ranging from 590 to 630 kilometers).

Even at lower altitudes with lower brightness, there’s no avoiding some disruption to astronomical observations. To minimize interference, the report calls on astronomers and satellite operators to develop software for tracking satellites and planning observations more precisely.

“There was this idea — well, actually it came from SpaceX — of having an app that we could all use, amateurs and professionals alike, to tell us precisely when something’s going to come across your field of view, and that’s beautiful,” Tyson said. “I think we can see the light at the end of that tunnel. … Any solutions that we come up with can be adopted by anybody, anytime.”

Tyson said software can also be used to remove some of the artifacts left behind in astronomical imagery by satellite trails. “The jury is out on that,” he said. “It’s quite challenging. These satellite trails are actually quite broad, so a fair fraction of pixels are impacted.”

As contentious as the satellite glare issue is today, it’s sure to get even stickier when the number of satellites rises from hundreds to thousands, to tens of thousands — and when the Vera Rubin Observatory hits prime time in the mid-2020s.

The Rubin Observatory’s wide-field Simonyi Survey Telescope — named after a billionaire software executive and space traveler who lives in the Seattle area — will be optimized to catalog thousands of near-Earth asteroids, study exoplanets in fine detail and shed light on the secrets of dark matter. But for all those efforts to be successful, the observatory will have to find ways to dodge all those satellites.

“It’s making a visual color motion picture of the universe,” Tyson said. “So it’s the perfect machine, unfortunately, to run into these things.”

A follow-up workshop, known as Satellite Constellations 2 or SATCON2, is tentatively planned for early to mid-2021.

Update for 7 p.m. PT Aug. 25: Meredith Rawls is a member of the team at the UW’s DIRAC Institute who also works on the data management team for the Rubin Observatory. What’s more, she contributed to a research paper that’s heavily referenced in today’s SATCON1 report. Here’s what she told me about the state of the satellite-vs.-sky controversy in an email:

“It’s heartening that SpaceX is working to darken their satellites, but they are just one operator. Dimmer satellites is not the same as fewer satellites. While there are lots of technical things that scientists can do to minimize scientific impacts, this is a significant amount of work that nobody has planned or budgeted for, and doesn’t begin to address wider-reaching environmental or cultural effects of a drastically changed night sky.”

Check out her talk about Starlink and the mega-constellation challenge, presented last month as part of the Astronomy at Home lecture series:

Wondering whether Starlink satellites are visible tonight from your locale? Plug your coordinates into Heavens-Above.com and find out.

Categories
Cosmic Space

Slush on Ceres widens hopes for water worlds

Occator Crater on Ceres
A mosaic image from NASA's Dawn spacecraft uses false color to highlight the recently exposed brine, or salty liquids, that were pushed up from a deep reservoir under Ceres' crust. In this view of a region of Occator Crater, they appear reddish. (NASA / JPL-Caltech / UCLA / MPS / DLR / IDA)

Even before NASA’s Dawn probe mapped Ceres in detail in 2015, scientists suspected that the dwarf planet was a water world. Now they’ve traced Ceres’ upwellings of salty slush and mud to reservoirs deep beneath the surface.

The details came out this week in a package of papers published by Nature Astronomy, Nature Geoscience and Nature Communications. The findings serve as a fitting coda to an 11-year mission that almost didn’t happen, but ultimately succeeded in solving many of the mysteries surrounding Ceres as well as its sister asteroid Vesta.

For example, consider the bright spots in Ceres’ Occator Crater, which some have likened to “alien headlights.” The reflectivity is due to a crust of sodium carbonate, a salt left behind by the evaporation of briny water that percolated up to the surface.

Gravity readings gathered during the latter days of Dawn’s mission led scientists to conclude that the brine came from a reservoir that’s 25 miles deep and hundreds of miles wide.

In one of the bright spots, known as Cerealia Facula, Dawn’s instruments detected a concentration of hydrated salt compounds. The fact that those compounds are still hydrated suggest that they must have reached the surface relatively recently — perhaps within the past few centuries. That suggests that the transfer of liquid material from Ceres’ deep reservoir is continuing.

“For the large deposit at Cerealia Facula, the bulk of the salts were supplied from a slushy area just beneath the surface that was melted by the heat of the impact that formed the crater about 20 million years ago,” Dawn principal investigator, Carol Raymond, explained in a news release. “The impact heat subsided after a few million years; however, the impact also created large fractures that could reach the deep, long-lived reservoir, allowing brine to continue percolating to the surface.”

Dawn’s scientists saw additional evidence for Ceres’ active, slush-based geology in the presence of conical hills reminiscent of earthly features known as pingos. On Earth, pingos are formed when pressurized groundwater freezes beneath the surface and pushes up the soil above. Similar geological structures have been observed on Mars.

On icy moons such as Europa, Enceladus and Titan, geological activity is primarily driven by gravitational interactions with their parent planets. The fact that Ceres is geologically active, even though its crust is not being flexed by a nearby planet, widens the possibilities for finding slush or liquid water deep within ice-rich worlds in the main asteroid belt, the Kuiper Belt and elsewhere.

The data-gathering phase of Dawn’s mission ended in 2018, and the dead spacecraft is now silently circling Ceres. But decades or centuries from now, the scientific findings resulting from the mission just might guide explorers to new kinds of interplanetary watering holes.

Categories
Cosmic Space

It’s prime time for the sky show in your backyard

David Dickinson
David Dickinson, author of "The Backyard Astronomer's Field Guide," sets up a telescope in his backyard. (Courtesy of David Dickinson)

Ready for a star party?

The COVID-19 pandemic has put a damper on summer star parties and other public gatherings, and skywatching isn’t exactly the kind of thing best done via a Zoom session. But you can still experience the wonders of the universe, just by looking up into dark, clear skies.

“The Backyard Astronomer’s Field Guide,” a newly published handbook by science writer David Dickinson, can help you do it.

“I pitch it as a star party in a book,” Dickinson explained.

This week is the summer’s big week for skywatchers:

  • The Globe at Night campaign is asking citizen scientists to report what they see in evening skies, to assess the effects of light pollution.
  • The Perseid meteor shower peaks on the nights of Aug. 10-13.
  • Four planets are on view: Jupiter and Saturn after sunset, and Mars and Venus before sunrise.
  • Although now is not the best time for Americans to spot the International Space Station, you just might be able to track the latest batch of SpaceX Starlink satellites as the stream across the sky. (Plug in your coordinates on Heavens-Above.com to check viewing times.)

Dickinson’s guide is designed to cover the more established targets of the night sky, ranging from the constellations to star clusters, nebulae and galaxies.

Forty-four sky charts, organized by month, point out wonders that can be found with the naked eye, with binoculars or with a telescope like the one that Dickinson sets up in his backyard or on the top floor of a nearby parking garage.

“Your observatory is wherever you’re observing,” he said.

Backyard Astronomer's Field Guide
“The Backyard Astronomer’s Field Guide” is spiral-bound for convenient use in the field. (Page Street Publishing / Laura Benton)

Dickinson also provides context that goes beyond latitude and longitude: Which naked-eye stars have planets orbiting them? What are the myths behind the constellation’s names, and what did other cultures see in them? What makes a planetary nebula “planetary”?

The guide includes a list of online tools, websites and publications to help you plot out your observing strategy — including Stellarium, a free planetarium program that’s priceless.

So what are the best deep-sky objects to turn your telescope toward while you’re waiting for the Perseids? Dickinson recommends M13, a globular star cluster in Hercules, the Ring Nebula in Lyra, the variable star Algol (a.k.a. the Demon Star) in Perseus … and Epsilon Lyrae, the “double-double” star in the constellation Lyra.

The double-double is famous, but somehow it was left out of the deep-sky catalog created by French astronomer Charles Messier in the 1700s. “I was always amazed that he missed things like the double-double,” Dickinson said.

You’re unlikely to repeat Messier’s mistake, as long as you have Dickinson’s field guide sitting next to your lounge chair (preferably consulted by the light of a red flashlight to preserve your night vision).

To celebrate the summer’s big week for skywatching — and reward you for reading down this far — I’m giving away a copy of “The Backyard Astronomer’s Field Guide.” Just be the first to answer this Cosmic Log quiz question in the comment section below:

What is the name of the closest planetary nebula to Earth?

The first person to answer correctly, based on my assessment of the time stamp, will be eligible to receive the book by mail (U.S. postal addresses only). If I can’t get in touch with that person via email in a timely fashion, I’ll move on to the next person on the list.

Back in the old days, Cosmic Log was known for its community of commenters, and I’m hoping we can revive that spirit. If you have a favorite night-sky object to observe, or a favorite resource for skywatching, pass it along in a comment. Your recommendation may end up in a future Cosmic Log roundup.

Update for 11:25 a.m. PT Aug. 9: We have a winner! Boris Zuchner was the first to answer the quiz question correctly, with an assist by Professor Google. As revealed on page 160 of “The Backyard Astronomer’s Field Guide,” the closest planetary nebula to Earth is the Helix Nebula, a.k.a. NGC 7293. Assuming that Boris’ mailing address is in the United States, he’ll be able to look that fact up himself in the future, thanks to the book I’ll be sending him.

As I wrote in the comments, don’t be a stranger! It took me a while to approve the comments this time around, but I’ll try to be faster on the draw for the next book giveaway.

Categories
Cosmic Space

Hubble uses eclipse to practice hunt for alien life

Hubble and lunar eclipse
An illustration shows the Hubble Space Telescope against the background of a total lunar eclipse. (NASA / ESA / M. Kornmesser)

Astronomers made use of the Hubble Space Telescope — and a total lunar eclipse — to rehearse their routine for seeking signs of life in alien atmospheres.

You’ll be relieved to know that the experiment, conducted on Jan. 20-21, 2019, determined that there are indeed signs of life on Earth.

The evidence came in the form of a strong spectral fingerprint for ozone. To detect that ultraviolet fingerprint, Hubble didn’t look at Earth directly. Instead, it analyzed the dim reddish light that was first refracted by Earth’s atmosphere, and then reflected back by the moon during last year’s lunar eclipse.

“Finding ozone is significant because it is a photochemical byproduct of molecular oxygen, which is itself a byproduct of life,” said Allison Youngblood of the Laboratory for Atmospheric and Space Physics in Boulder, Colo., lead researcher of Hubble’s observations.

Other ground-based telescopes made spectroscopic observations at other wavelengths during the eclipse. They were looking for the fingerprints of different atmospheric ingredients linked to life’s presence, such as oxygen and methane.

This wasn’t just an academic exercise. Astronomers hope future observatories, such as the James Webb Space Telescope and the Roman Space Telescope, will be able to detect life’s fingerprints in the atmospheres of faraway exoplanets. But that takes practice.

“One of NASA’s major goals is to identify planets that could support life,” Youngblood said in a Hubble news release. “But how would we know a habitable or an uninhabited planet if we saw one? What would they look like with the techniques that astronomers have at their disposal for characterizing the atmospheres of exoplanets? That’s why it’s important to develop models of Earth’s spectrum as a template for categorizing atmospheres on extrasolar planets.”

Check out the news release for further details, or delve into the research paper published today in The Astronomical Journal. And to learn more about how lunar eclipses work, check out this “Inconstant Moon” interactive (after you enable Flash in your browser).

This report was published on Cosmic Log. Accept no substitutes.