by Paul Gilster | Jul 10, 2009 | Asteroid and Comet Deflection |
The driver who took me from Aosta to Milan yesterday evening spoke no English, but he was an affable young man who had a love for fast cars. As we drove along a fine Alpine highway, a low red sports car moved fast us so quickly that I almost didn’t see it. But suddenly the driver, who had said next to nothing thus far, erupted with “Italian car! Beautiful!” He stretched out the last word as if savoring the idea, then looked over at me making a thumbs up. Well, it was beautiful, and it was followed by two more similar cars making speeds I could only guess at. I wondered what it felt like to drive such a car, and how quickly it would get to Milan.
One of the best things about wrapping up the Aosta conference, which we did with a farewell party yesterday afternoon, is that I head back to the States with a satchel full of papers. I’ve only been able to mention a few of them thus far, but next week I should have the chance to talk about them at more leisure. Here in Milan I have a few minutes before I have to leave for Malpensa airport, so I thought I would mention Greg Matloff’s paper on using Near-Earth Objects in a novel and intriguing way. Greg (New York City Technical College, CUNY) has a student named Monika Wilga who worked with him on the concept of using NEOs to hitchhike to Mars.
Now Mars wouldn’t seem to have much to do with this conference, because it is, after all, explicitly focused on missions to the outer Solar System and beyond. But it turns out there is an interesting outer system component here, not to mention a fascinating concept in and of itself. Greg put Ms. Wilga to work on finding any NEOs that cross close enough to Earth to make a mission there a viable one within a relatively short time, thus minimizing the danger of exposure to high-energy cosmic rays, whose health hazards on a long mission could be severe. He then asked her to further constrain the list to those NEOs that went on to pass close to Mars.
Image: Greg Matloff, taken at our visit to Giancarlo Genta’s summer house high above Aosta.
The idea here is that the astronauts can use the NEO as a radiation shield, digging in to its surface and exploiting its resources on the way to the red planet. Greg presented a table showing candidate objects that could fill the bill, including two — 1999YR14 and 2007EE26 — that have one Earth-Mars transit time amounting to one year or less. Let me quote the paper (and then I need to pack it and get going to Malpensa):
Since orbital characteristics are known for a few thousand NEOs, it is reasonable to assume that about 0.1% of the total NEO population could be applied for Earth-Mars or Mars-Earth transfers during the time period 2020-2100. Because a few hundred thousand NEOs must exist that are greater in dimension than 10m, hundreds of small NEOs must travel near-Hohmann trajectories between Earth and Mars or Mars and Earth. It seems likely that a concerted search will find one or more candidate NEOs for shielding application during any opposition of the two planets.
The outer system wrinkle to all this is that when Greg had his student repeat the study with the maximum aphelion distance of the NEOs stretched to 2.5 AU, no new Earth-Mars candidates were found. But a NEO called 2000WO148 passes Earth in January of 2041 and goes on to the main belt asteroid Vesta in October 2043. Now there’s an interesting mission possibility built right into the local NEO population. We should be able to find more candidate NEOs as detection sensitivity increases, so human journeys to other main-belt asteroids by this method may become feasible. Fascinating stuff and I’d like to say more, but I have a plane to catch.
by Paul Gilster | Jul 9, 2009 | Culture and Society |
I’m just in from an early morning walk around the streets of Aosta, enjoying a brisk spring morning. The streets at this hour are largely empty and the Sun lights the nearby peaks. We have a heavy session of papers on this last day of the conference, and we had an even longer day yesterday, followed by my public lecture at the Aosta town hall last night. Following the talk, Giancarlo Genta, his lovely wife Franca, and Guido Cossard, the assessore of cultural affairs (who turns out to be an astronomy buff and something of an expert on archaeoastronomy), took me on a walk around town looking at medieval and Roman sites. We wound up having a late night beer and I didn’t get in until 1:30.
This is a travel day, as I change hotels in preparation for tomorrow’s flight from Milan. So I’m going to hold any of the discussion about the papers yesterday, which were so rich that I’d prefer to get into them when I have more than a few minutes. In particular, the solar sail sessions opened my eyes to a signficant problem in sail missions. Run a sundiver mission near the huge gravity well of our star and you experience effects including frame-dragging and other consequences of General Relativity that can have a serious impact on where your sail winds up going. The effect is particularly noticeable for fast, long missions and hence of interest to us here. More on this when I can — I hope I’ll have a good Internet connection in Milan.
by Paul Gilster | Jul 8, 2009 | Culture and Society |
Today we get into the heart of this interstellar conference, with multiple sessions on propulsion via solar and electric sail, as well as looks at specific mission concepts and robotic applications in deep space. I spent a good part of our bus ride back from Bard castle yesterday talking to Pekka Janhunen, creator of the electric sail concept, about its possible interstellar applications. Pekka does not believe this system, based on electric tethers riding the solar wind, could muster the velocity to go interstellar, but he does see it as a viable candidate for braking into a destination system, and just as important, exploring it. I’m anxious to get the latest on his work and also to look at fusion alternatives, which Claudio Maccone will present now that we’ve learned that Claudio Bruno can’t make it here.
As I get ready for the day to start, I’ll drop in here some notes from the first day. These are no more than a skeletal outline — I’ll use the conference proceedings when I get back to take a close look at some of these presentations, but I don’t want to rush through any complex arguments out of a need to get a post up.
Image: The opening session. That’s conference organizer Giancarlo Genta at the left, then (left to right) J.-M. Content, Guido Cossard (assessore of cultural affairs in Aosta) and Giovanni Vulpetti at far right.
Our opening session of the Aosta conference — technically, the Sixth IAA Symposium on Realistic Near-term Advanced Scientific Space Missions — got off to a late start, as so many meetings do, at the Aosta town hall on Monday. The keynote was a genial overview of the International Academy of Astronautics by its secretary general, J.-M. Content, who walked us through the major events that had shaped the organization. My session on ‘Interstellar Flight and the Public Imagination’ followed after a coffee break and we were off. Marco Bernasconi (MCB Consultants) followed me, which was fortuitous because we discussed many themes in common. Dr. Bernasconi has been working on human motivations for deep space travel for some time now and has developed an interesting libertarian perspective on the issue.
A short lunch at the hotel allowed us to get back on schedule in the conference rooms on the lower level, where Les Johnson (NASA MSFC) discussed NanoSail-D. Interesting to learn that there is no NanoSail-A, B or C — the ‘D’ stands for drag, and refers to the fact that in order to get the attempted launch funded, the Marshall Space Flight Center team had to sell the sail on the basis of its drag properties, useful in deorbiting satellites. That launch, of course, failed, another sail attempt wrecked not by the sail technology itself but by booster problems. Remember, a second NanoSail-D is still on the shelf in Huntsville. When will it fly?
Roman Kezerashvili (New York City College of Technology) talked about solar sails in the context of non-Keplerian orbits, but what I remember most about the afternoon was Kezerashvili’s impassioned defense of nuclear technology as the propulsion choice for the next step in space exploration. Giancarlo Genta, the organizer of the Aosta conference, spoke in his talk about the ‘nuclear renaissance’ in terms not only of the space program but also of the power industry. I want to get back to both the Genta and Kezerashvili talks later when I can go through their papers in detail. A second part of Kezerashvili’s argument will be presented on Thursday.
Image: Giancarlo Genta (Politecnico di Torino) answers a question during the afternoon session.
My erstwhile opponent in the interstellar bet, Tibor Pacher, made a pitch for unconventional thinking in presenting interstellar issues — these included a discussion not only of how we are using the Long Bets site to provoke discussion and commentary, but also of his own ‘Crazy Ideas’ section on the peregrinus-interstellar site and broader uses of social networking to get the public involved. Tibor made a huge and telling point when he looked around the room and asked: “Where are the young people?” Indeed, he himself was one of the youngest in the room and, as he told the crowd, he was almost 50. Here we were in Aosta discussing some of the cutting-edge technologies that might one day get us to the stars, and where were the students you would expect to find, the young intellects anxious to push that agenda? Tibor hopes his methods will help to remedy the lack, and so do I.
Image: Tibor Pacher (on the left) and I had paused to take in the view from Bard Castle when Claudio Maccone took this picture.
We also had an interesting talk on the psychological aspects of long-term flight from Nick Kanas (University of California at San Francisco), who brought his psychiatric credentials to bear in discussing how crews on long missions aboard Mir and the ISS have fared. All in all, a fine first day, capped by a banquet in the hotel dining room which was, as all our meals here have been, excellent. Giancarlo Genta turns out to be one of the great dinner companions in addition to being a crack symposium organizer. I’ll long remember our conversation about the history of the Aosta region. And Tuesday’s travels — we had a sightseeing day rather than any scientific sessions — were capped with a stop by his just completed summer home high above the valley, a glorious view of snow capped peaks dominating the sky, followed by a traditional Aosta dinner at a nearby restaurant. I’ll post some pictures of this in a day or two.
by Paul Gilster | Jul 7, 2009 | Culture and Society |
I had intended to use today’s post to talk about yesterday’s sessions here in Aosta, but it’s going on midnight here, and tomorrow will clearly not afford any opportunities to write. Tuesday turns out to be our sightseeing day. We leave the hotel at 9:00 and head for Verrès, where we visit the Mechatronics Laboratory of the Politecnico di Torino. Then we head up into the mountains, visiting the Bard fortress, with individual visits to the Museum of the Alps. After lunch at what is said to be an excellent restaurant called La Polveriera, we go to an exhibition called ‘Verso l’alto, l’ascesa come esperienza del sacro’ — Towards the heights: The ascent as experience of the sacred. Then to dinner at the Hotel Notre Maison, where we are promised traditional Aosta Valley food.
Image: The Aosta town hall, where our opening sessions were held. Later, we moved to the Hotel Europe.
As for tomorrow, we don’t get back to the hotel until midnight. No more today or I’ll be late for the bus, but I’ll hope to get more posted on Wednesday, when we return to our scientific schedule. Until then, imagine me bumping up narrow mountain roads looking at Alpine scenery in a bus stuffed with space scientists!
Image: A motley crew. From left to right, Giovanni Vulpetti, Claudio Maccone, Greg Matloff, Les Johnson, as we stood outside the hotel waiting for last night’s banquet to begin. If these guys can’t get us into deep space, nobody can.
by Paul Gilster | Jul 6, 2009 | Culture and Society |
What I’ll surely remember the most about arriving in Italy is the sight of snow on the Alps as the plane descended out of a cloudy morning sky into Milan. But right after that comes the two hang gliders that soared past an alpine peak as the van that was taking me to Aosta moved north toward the town, the landscape becoming a series of valleys cutting through the steep clefts. The second of the two hang gliders looked for all the world as if it were going to land right on the highway, a daunting thought given how the traffic was moving, but as we rounded a turn I saw that it had caught an updraft and was angling out and away. What a view the pilot must have had.
Image: The view from my room at the Hotel Europe in Aosta. It was hot and humid when I took this, but cooled off dramatically during the night. If the air conditioner worked, all would be perfect. Below is a photo from the street in front of the hotel. As you can tell, this is the place to be for a guy who loves mountains the way I do.
The day after, it’s a glorious morning in northern Italy, the humidity and heat of yesterday afternoon giving way to cool, dry air, although space scientist Giovanni Vulpetti told me last night at the welcome party that the weather in these parts changes by the hour. Indeed, a brief rain had blown in as he was speaking, cooling and freshening the night. The party was a welcome chance to renew acquaintances, but I was so tired from the flight that I retired early. This morning, in a few minutes, we head to the Aosta town hall for the opening session of the conference. I’ll report on matters when possible, but I may have to hold most of my remarks until I get back. The Net connection here is tricky and usable only from the hotel lobby, and time may become a factor as well. Meetings and hallway conversations are burning ninety-nine percent of my time (well, not to mention the chance to have some fabulous food — the vegetable risotto last night was unforgettable).
