Herschel’s observation of comets

To say that Woody Sullivan is interested in William Herschel would be quite an understatement.

“I have dressed up as Herschel for Astronomy 101 half a dozen times,” said Sullivan, a professor emeritus of astronomy at the University of Washington. He started a file on Herschel, the 18th and 19th Century astronomer, some 30 years ago, but can’t exactly pin down why he was so drawn to him.

“I have eclectic interests,” Sullivan said. “I’m always looking for what I call astronomy on the edges: astronomy and music, astronomy and astrology, history, literature, sundials.”

“Herschel was that way to some degree,” Sullivan added. “Perhaps that was it; I saw a fellow traveler there.”

Woody Sullivan

Prof. Woody Sullivan at the May meeting of the Seattle Astronomical Society. (Photo: Greg Scheiderer)

Sullivan noted that it was nine years ago that he started doing more serious research into Herschel with the intent to write a biography. While there have been many penned, including a couple in the last decade or so, Sullivan noted that none have been particularly scholarly, and so that’s a void he’s aiming to fill. After all of that research, the actual writing has begun.

“I do need to get on because I’m getting on,” Sullivan quipped. He spoke about his work at the most recent meeting of the Seattle Astronomical Society, discussing Herschel’s work on comets, about which few biographers have gone into much detail.

While his sister Caroline Herschel discovered eight comets, six of which bear her name, William never found one, though he came close a couple of times. He once reported a comet discovery, but the French astronomer Jean-Louis Pons had already found it a month before. Then in 1781 Herschel reported another comet discovery. But after six or eight months of observation, astronomers more skilled in the calculation of orbits found this new object to be in a nearly circular one well beyond Saturn’s. It was a new planet: Uranus.

First to “discover” a planet

“It’s hard to think about what a new planet means. What planets did we have before? We had the same planets that we had had since Ogg the caveman,” Sullivan noted. “Herschel was the first one to find a planet telescopically, and this made him instantly famous.”

William Herschel

William Herschel. (Photo: Public domain)

Herschel parlayed that into a gig as the court astronomer for King George III. It was actually a pay cut from Herschel’s work as a professional musician in Bath, but he supplemented his income by building and selling telescopes, and by marrying a rich widow. Herschel was mostly interested in deep-sky objects, but comets came to his attention on occasion, in part because he was interested in change.

“A comet is change par excellence,” Sullivan said. “It just appears in the sky, it’s different every day, you never know what’s going to happen.”

While Caroline wanted to discover them, William aimed to understand what they were. Sullivan noted that this wasn’t what most astronomers were doing then.

A different sort of astronomer

“Astronomy at that time was measuring accurate positions of things; planets and their moons and comets and stars for catalogs,” he said. “That’s why you had the Greenwich Observatory. The government was paying for that, not because they loved astronomy but they loved the navy, and you needed that for navigation.”

Herschel’s observations of the great comets of 1807 and 1811 were interesting. Sullivan pointed out that astronomers at the time thought there might be a planet or other object at the nucleus of a comet. Herschel was the first to claim he’d spotted one. When others couldn’t find it, Herschel chalked it up to the superior optics of his telescope. By the 1811 comet, he was trying to figure out if the nucleus reflected light from the Sun, or generated its own light. Herschel declared that the nucleus of this comet was perfectly round, and thus self-illuminated, because if it reflected light it would show phases. Sullivan, after poring through Herschel’s logs, concluded that he had fallen into a trap that scientists need to avoid.

“There’s just no doubt that he was picking and choosing the observations that fit into his concept,” Sullivan said. It was a bit of a reach to claim to be able to determine the roundness of an object of perhaps an arcsecond in width within the fuzzy coma of a comet.

“He’s getting all of his theory and observations mixed up,” Sullivan said. “This can get you in trouble.”

Though Herschel missed on this particular analysis, Sullivan noted that Herschel made some interesting conclusions, particularly in describing the tail of a comet as its atmosphere being pushed away by pressure from the Sun. Though it’s not the atmosphere, but dust and gasses, nobody to that point had really postulated that the Sun might be pushing on things. Other descriptions Herschel made of the mechanics of comets are not so far off from what is held true today.

Sullivan’s presentations are always interesting, and we look forward to the completion of the book and to learning about William Herschel, a fascinating character in the history of science.


 

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AstronoMay and more at PacSci

It’s been a month filled with astronomy at Pacific Science Center, and they’ll wrap it up big this weekend with their celebration of AstronoMay Saturday, Sunday, and Monday. According to Dave Cuomo, supervisor for science interpretation programs and the Willard Smith Planetarium at the center, there will be a lot going on.

“We will have expanded planetarium shows,” Cuomo said. “We will have lectures about astronomy featured on our Science on a Sphere exhibit. We will talk about astrobiology in some of those. We will have space scientists that visitors can speak with and talk about their study and research about astronomy. And, weather permitting, we will have some solar telescopes out so you can safely observe the Sun.”

Planetarium-palooza

Willard Smith PlanetariumThere’s a great variety of selections for shows in the planetarium. One that will run this weekend is called “The Search for Life.”

“It will be an exploration of the different ways that astrobiologists are looking for life, both in the solar system and outside of the solar system,” Cuomo said. That show is a great complement to the “Mission: Find Life!” exhibit about astrobiology that is presently in the center’s Portal to Current Research space. (See our post from last month for more about that.) Another show, titled “Let’s Explore Light,” is about the basic physics of light.

A third planetarium show called “The Skies of Ancient China,” created to complement the popular Terracotta Warriors exhibit at the center, looks at more than 4,000 years of Chinese astronomy. Cuomo noted that Chinese astronomers in the day had a pretty high-stakes job.

“They were hired by the emperor because the emperor ruled the Earth because he had the mandate from the heavens,” Cuomo explained, “so he needed to be able to know what was going to happen in the sky.”

The astronomers predicted planetary conjunctions and eclipses of the Sun and the Moon. Conjunctions in particular were considered omens of pending regime change, and, say what you will about whether the heavens influence lives on Earth, a couple of empires actually did flip at around the time of a conjunction. More amazing is the accuracy of both the Chinese astronomical observations and their record keeping.

“Modern astronomers have associated at least nine supernova remnants with ‘guest stars’ that the Chinese observed and recorded the location of,” Cuomo marveled. “There is also almost two thousand years of history of a returning star every 76 years, which we now know was Halley’s Comet.”

Cuomo found it interesting that there wasn’t much mythology around the heavens with the Chinese astronomers as compared to that in many other cultures. He and three of the center’s planetarians created the show with research help from the British Library, the Hong Kong Space Museum, and many others across the country and the world.

The daily schedule for planetarium shows is on the PacSci website and also on our Seattle Astronomy calendar page. We saw “The Skies of Ancient China” last week and found it to be exceptionally well done.

Solar eclipse

The astronomy doesn’t stop once May ends. The Pacific Science Center is gearing up for the total solar eclipse that will happen on August 21. The entire month of August will be PacSci “Up in the Sky.”

“We will talk about solar astronomy, observational astronomy, weather; anything that you look up to see, we’ll want to talk about,” Cuomo said. They’ll also have eclipse glasses on hand for safe viewing of the Sun, and probably some solar projectors for watching the eclipse.

Although the eclipse will only be partial in Seattle, the center plans to open early, at 8:30, that morning.

“We will have solar telescopes available and educators talking about the eclipse and the science of the eclipse,” Cuomo said. First contact—when the Moon starts moving across the face of the Sun—will happen at 9:08 a.m. at PacSci, and it will be over by 11:30. But they’ll have live feeds from other eclipse events from all across the country so you can keep watching.

Cuomo will be in Madras, Oregon for the total eclipse, along with other educators from the Pacific Science Center in partnership with Lowell Observatory. They’re leading a four-day trip to view the total eclipse. Space is limited; if you’re interested in going along, you can find out more online.


Podcast of our interview with Dave Cuomo

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Apollo exhibit touches down at Museum of Flight

The folks at the Museum of Flight have done their level best to make their new Apollo exhibit that opened last weekend all about the people who made the Moon landings happen. But there’s no doubt that two enormous F-1 engines that launched people to the Moon dominate the gallery. One is an unused engine that towers 18 feet tall above the exhibit and weighs nine tons. The other is mangled parts of engines from Apollo 12 and Apollo 16 that flew to space, did belly flops from 40 miles above the Atlantic Ocean, and then spent more than forty years some three miles deep before being found and recovered by Bezos Expeditions.

Geoff Nunn

Geoff Nunn, adjunct curator for space history at the Museum of Flight, explains that the Apollo F-1 engines are really, really big. (Photo: Greg Scheiderer)

The exhibit has been a couple of years in the making. Planning started with the opening of the museum’s Charles Simonyi Space Gallery the the acquisition of the Space Shuttle Trainer that is the centerpiece of that gallery. That moved the shuttle, post-shuttle, and looking to the future exhibits across the street, and gave museum staff the opportunity to create a new exhibit that focuses on the beginning of modern rocketry, the space race, the Moon landings, and the post-Apollo 1970s.

Geoff Nunn, adjunct curator for space history at the museum, said they had several objectives for the exhibit.

“We wanted to showcase the tremendous artifacts,” Nunn said at a press preview of Apollo. “We wanted to reintegrate the Pete Conrad collection into the broader story of the space race and the Moon landings. We wanted to showcase these incredible, one-of-a-kind artifacts that have been through so much in their life—through fire and, in the case of the Apollo 12 engines, lightning, and then impact with the sea floor and 40 years deep, deep under water.”

Indeed, the two Apollo engines provide an amazing before and after comparison, and there are other great artifacts on display. The exhibit also features:

  • A production version of the Apollo command module that was used for training
  • An engineering mockup of a lunar rover, built by Boeing in Kent
  • A mockup of the Apollo 17 lunar module ascent stage
  • A Viking Mars lander

The museum has a lot of artifacts from astronaut Pete Conrad, the Apollo 12 commander. Among those on display are a cuff checklist Conrad used to keep track of tasks on the Moon, a mix tape he played on Skylab that includes personal messages from the likes of Loretta Lynn, Conway Twitty, and Tom T. Hall, and a rock Conrad brought back from the Moon.

David Concannon is the deep sea explorer hired by Amazon founder Jeff Bezos to lead the search for and discovery of the F-1 engines. (See our story from November 2015 for more.) Concannon, who has also recovered artifacts from the Titanic, was still in awe at the press preview last week.

“These engines tell an magnificent story of a time in America when everybody came together, pulled together to do something magnificent,” Concannon said. “To me, that’s the story that these beat-up, burned-up artifacts tell.”

They tell it remarkably well. Don’t miss it!

A few highlights of the Apollo exhibit (click for larger versions):


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Mars “big thinkers” envision people on the Red Planet

After hearing about the pros, cons, and challenges of sending people to Mars, most of the audience who attended “National Geographic: Mankind to Mars” at Benaroya Hall Monday evening decided that such an effort would be worthwhile. A significantly smaller percentage of attendees would be willing to make the trip themselves.

The straw poll by applause came after a panel discussion moderated by Andrew Fazekas, also known as The Night Sky Guy, a space journalist who writes a column for National Geographic and who is the author of Star Trek; The Official Guide to Our Universe: The True Science Behind the Starship Voyages (National Geographic, 2016). The other panelists were Jedidah Isler, an astrophysicist from Vanderbilt University, and Ray Arvidson, a planetary scientist at Washington University in St. Louis who has had a hand in Mars missions going back to Viking in the 1970s and is the deputy principal investigator for the Mars rover Opportunity mission.

Why Mars?

Fazekas said he got interested in space when he was a little kid and his father showed him Mars through a telescope.

“Mars has always been particularly fascinating to humankind because it’s our nearest neighbor,” Fazekas said, “a neighboring world that beckons us.”

Panel at Mankind to Mars

(L-R) Andrew Fazekas, Jedidah Isler, and Ray Arvidson discuss “Mankind to Mars” May 15, 2017 at Benaroya Hall in Seattle. Photo: Greg Scheiderer.

The presentation made liberal use of video clips and images from the Mars miniseries aired by the National Geographic Channel last fall. The panelists covered a wide range of topics, including the history of Mars, its past possible habitability, research by rovers and orbiters at Mars and by people on Earth, rocket and spacecraft design, private space ventures, and the possible setup for a human outpost on Mars.

They also discussed a litany of challenges to making a successful human mission to Mars happen, including getting there and landing safely, radiation, dust, fuel and power, agriculture on Mars, and a host of threats to human physical, mental, and emotional health.

Isler said she’s interested in the “socio-technological” aspects of a human mission to Mars, and thinks interest is building because we keep learning.

“It seems like a good amount of information is there, we’ve got a lot of poepole interested in it,” she noted. “I think it’s just a good time because we’ve got all the right pieces, or many of them.”

There’s also important science to be done, Arvidson said.

“What we’re looking at on Mars is the record in the rocks that’s long lost on Earth,” he said. “It’s the first billion years of geologic time. Earth is very active; Mars was active early but then kind of slowed down, so the rock record is still preserved. That’s the period of time when life got started and evolved on Earth. It may have also gotten started and evolved on Mars.”

Where to land

Scientists are debating right now about possible human landing sites on Mars, and dozens of them have been proposed by people with varying scientific interests. Arvidson said it will take many years to whittle those down and make a choice. The target spot will have to be one that is safe to land on, away from the poles and at low elevation so it is not too cold, and will need to offer a balance between science, safety, and sustainability.

“Wherever we go, there are lots of questions about early Mars and habitability and life,” Arvidson said. “I think the first human expedition site will be a science station, most likely, for detailed exploration between humans and robotic systems.”

Isler said that machines will do a lot of work, but that people are essential for the ultimate success of a Mars mission.

“Robots are beneficial, but they are limited,” she said. “You will always want, I argue, the dynamism, the spontaneity of human beings.”

When shall we start packing?

“Depending on what we want to do, nationallly and internationally, where the finances are, and what the reasons are and the justification, we can do this in the next few decades,” Arvidson said, speculating that we’ll arrive on Mars in the 2040s. Isler thinks it will take longer than that to figure out the human factors involved.

“The rumor on the street is that we’re always 20 years from Mars,” she quipped.

The panel speculated about an “Armstrong moment” on the day that a person from Earth sets foot on Mars for the first time. Isler said it will be a “moment where people will be be super connected with the fact that we as a species have now moved ourselves to this place successfully.”

But she added that we need to be careful how we talk about the endeavor, as huge numbers of people have been thinking about and working on getting humans to Mars for years.

“We have to do a better job this time around of implying and also asserting that it wasn’t just one person, this was not rugged individualism,” Isler said. “This is a team effort.”

She also thinks it will go a bit differently than Neil Armstrong’s line after stepping onto the Moon.

“When the first Mars explorer steps off she might Snapchat,” she laughed.

Fazekas seemed most optimistic about the timeline.

“If we put all of these components together—the technology, the science, the engineering, the willpower, understanding the challenges—we may one day all have a chance to become a tourist on Mars,” Fazekas said.

Further reading and viewing:

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Astro Biz: Down to Earth Session IPA

Down to Earth IPAMany businesses, products, and places have names rooted in space and astronomy. We’re featuring one every Tuesday on Seattle Astronomy.

This week’s Astro Biz is Down to Earth Session IPA from 21st Amendment Brewery in the San Francisco Bay Area. Now, we at Seattle Astronomy love a good brew, and we discovered this one in our local supermarket as part of our constant search for the perfect “house” IPA. But we’d never heard the term “session” before. According to AmericanCraftBeer.com, the term originated in WWI-era England, in which folks were typically allowed to drink beer on the job, even if they were making weapons of war. Workers were allowed two four-hour drinking sessions during the work day. This called for something a bit lighter, so as not to lose the productivity boost to be gained from a good quaff or three. The site goes into somewhat more detail in defining the parameters of session beer.

Anyway, the Down to Earth get thumbs up from us, and it is a bit lighter at 4.4 percent alcohol by volume, and 42 bitterness units (IBUS). Also, we love the space chimp art on the cans and six-pack.

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Lots of great choices for astronomy events this week

There are tons of great astronomy events on the calendar this week, topped by the opening of the Museum of Flight’s Apollo exhibit and a visit from the Night Sky Guy.

Apollo

ApolloA couple of years in the making, the new Apollo exhibit opens Saturday, May 20 at the Museum of Flight, though museum members can get an early sneak-peek Wednesday evening. The exhibit includes the F-1 engine parts fished out of the Atlantic Ocean by Bezos Expeditions, an intact F-1, and many more great space exploration artifacts. Check out our recent article and podcast previewing the exhibit.

The Museum will also hold its annual Space Fest over the weekend with a variety of presentations, exhibits, and discussions focused on Apollo and the Moon.

The Night Sky Guy and Mars

Andrew Fazekas, aka The Night Sky Guy, is in Seattle for three talks at Benaroya Hall. Titled “Mankind to Mars,” the event will be an exploration of what it will take to get humans to the Red Planet. It’s produced in conjunction with the Mars miniseries created by the National Geographic channel. One show was Sunday afternoon, and Fazekas also appears on Monday, May 15 and Tuesday, May 16, both at 7:30 p.m.

Fazekas is the author of Star Trek: The Official Guide to Our Universe: The True Science Behind the Starship Voyages (National Geographic, 2016).

AstronoMay at PacSci

Pacific Science CenterAstronoMay is under way at the Pacific Science Center, and a couple of interesting events are on the calendar for this week. Astronaut Nicholas Patrick will host a viewing and discussion of the film A Beautiful Planet 3-D at 7 p.m. Tuesday, May 16. The film is a portrait of Earth from space captured by the astronauts aboard the International Space Station. Patrick will introduce the show and lead a Q&A session after. He’s now with Blue Origin; see our article about Patrick’s recent talk at Astronomy on Tap Seattle. Admission is $10, or $5 for science center members.

Then learn the ABCs of total solar eclipses, and get ready for the one that will be visible in parts of the United States in August, with Dennis Schatz, nationally recognized astronomy educator and Pacific Science Center senior advisor. Total Solar Eclipse 101 happens at 7 p.m. Wednesday, May 17. Cost is $5, free for members.

JWST

RiekeNASA’s next great space observatory, the James Webb Space Telescope (JWST), is scheduled for launch in October 2018. George Rieke, a professor of astronomy at the University of Arizona and science team lead for the Mid-Infrared Instrument (MIRI) that will fly onboard the scope, will speak at the University of Washington astronomy colloquium at 4 p.m. Thursday, May 18. The talk will focus on the capabilities of JWST, emphasizing the advances over present (and even some future) facilities, with examples of the science it will enable.

Club events

Rose City Astronomers will hold their monthly meeting at 7:30 p.m. Monday, May 15 in the OMSI auditorium in Portland. It will be their annual swap meet and astronomy information fair. The club, along with OMSI and the Vancouver Sidewalk Astronomers, will host public star parties at 8 p.m. Saturday, May 20 at both Rooster Rock State Park and L.L. “Stub” Stewart State Park.

The Island County Astronomical Society will hold its monthly meeting at 6:30 p.m. Monday, May 15 at the Oak Harbor Library.

The Seattle Astronomical Society monthly meeting will be at 7:30 p.m. Wednesday, May 17 in room A102 of the Physics/Astronomy building on the University of Washington campus in Seattle. Guest speaker Woody Sullivan, professor emeritus of astronomy, will talk about the contributions of William and Caroline Herschel to our understanding of comets. Sullivan is working on a biography of William Herschel.

The Tacoma Astronomical Society plans one of its free public nights for 9 p.m. Saturday, May 20. The topic for the indoor presentation will be black holes. If the weather cooperates they’ll break out the telescopes for some observing.

TJO

Theodor Jacobsen ObservatoryThe bi-monthly open house at the UW’s Theodor Jacobsen Observatory is set for 9 p.m. Wednesday, May 17. The topic for the evening’s astronomy talk has not been published. It’s a good idea to make reservations early, as these typically are filled up. Volunteers from the Seattle Astronomical Society will conduct tours of the observatory dome and, weather permitting, offer a look through its vintage telescope.

Planetarium shows

The Bellevue College Planetarium will run a public show about black holes at 6 p.m. and again at 7 p.m. on Saturday, May 20. The show will include animations of the formation of the early universe, star birth and death, the collision of giant galaxies, and a simulated flight to a super-massive black hole lurking at the center of our own Milky Way Galaxy. It’s free, but reservations are suggested. See the website for registration info and other details.

The Willard Smith Planetarium at the Pacific Science Center offers a variety of shows every day. Their full schedule is posted on our calendar page, where you can also scout out more future astronomy events.

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Mars Insider gives the scoop on Red Planet missions

To work for the NASA Jet Propulsion Lab (JPL) it would probably be helpful if you had some juggling skills.

“At JPL we have 24 flying missions in deep space,” said spacecraft engineer Terry Himes, who has had a hand on most of those craft. Himes gave a talk titled “Mars Insider” recently at the Museum of Flight.

Terry Himes

NASA JPL spacecraft engineer Terry Himes spoke at the Museum of Flight April 29, 2017 about his work on various missions. Photo: Greg Scheiderer.

“Our job as spacecraft engineers is to keep the health and welfare of the spacecraft,” Himes said, and that’s a job that doesn’t always line up with the science goals of the mission.

“The science guys want to go to the worst possible places on the planet,” Himes laughed. “They want to go to horrifying places and land in crevasses and do all kids of crazy stuff. We (engineers) want to land on flat, sandy plains.”

Thus choosing a place to land is a battle from day one and can often be a lengthy discussion, Himes said. For the Mars Science Lab Curiosity, for example, the science team wanted to land as close as possible to Mount Sharp on Mars so they could explore the geology there. They were able to land in a tight spot by using the controlled descent of Curiosity’s incredible landing method. Himes noted that the target landing area for Mars missions, known as the “landing ellipse,” has been shrinking over the years. While Viking had a landing ellipse 300 kilometers long, they dropped Curiosity into a target of just 18 kilometers.

“It’s like hitting a golf ball in San Diego and making a hole-in-one in New York,” Himes said.

Once a lander is on the ground there’s another daily discussion about what it will do next. This is typically based on photos sent back from the activities of the previous sol, or Martian day. They consider interesting nearby objects, any hazards in the area, and the overall health of the rover. Himes noted that Curiosity’s wheels have taken a beating from hard and sharp rocks on Mars. He also related a funny story about the wheels.

A message in the sand

NASA had told the spacecraft team that they couldn’t put a logo or any other mention of JPL on Curiosity because the project involved all of NASA and scientists from other countries, too. They got around that by putting cutout grooves in the wheels that are Morse code for the letters, so that every time those wheels turn they leave J-P-L in the Martian sand.

“Don’t mess with engineers,” Himes laughed.

A little InSight about Mars

The next project for Himes will be InSight, which after a recent delay is now scheduled to launch next May and land on Mars in November of 2018. InSight, which is short for Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport, will help us figure out how rocky planets form and evolve. The craft will be a modified version of Phoenix, another mission Himes worked on, which found ice near the north pole of Mars in 2008. InSight will have a couple of new instruments.

InSight The Mole

This artist’s concept depicts the InSight lander on Mars after the lander’s robotic arm has deployed a seismometer and a heat probe directly onto the ground. InSight is the first mission dedicated to investigating the deep interior of Mars. The findings will advance understanding of how all rocky planets, including Earth, formed and evolved. Image: NASA/JPL-Caltech.

The first is the Heat flow and Physical Properties Probe, or HP3, which Himes says they’re calling simply “The Mole.”

“It’s a heat transfer mechanism,” Himes said. “We’re going to go into the surface of Mars and conduct heat experiments, see how much heat is there.” The mole will be driven some five meters into the ground on Mars.

The other instrument is the Seismic Experiment for Interior Structure, or SEIS, a “very broad band” seismometer sensitive enough to detect meteor strikes way on the other side of the planet. These two instruments will give scientists information about the inner workings of Mars.

There are a couple more Mars missions on the drawing board. Mars 2020 will be a lander much like Curiosity—NASA can save some cash by re-using spacecraft designs if they can serve the purpose—and it will look for signs of past microbial life on Mars, explore the possibility for creating oxygen in the Red Planet’s atmosphere, and do a variety of other experiments.

NeMO, the “next Mars orbiter,” will provide another communication link should a current orbiter fail, and it also could be part of a plan to return pieces of Mars to Earth.

“Mars 2020 may be depositing samples that it gathers in canisters and leaving them around,” Himes said, “and then NeMO may have something that’s going to go down to the surface, pick them up, and come back, and return to Earth.” Himes noted that plans for NeMO are still quite preliminary.

As these missions are developed it seems likely that Himes will be in the middle of it all.

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