?A few words before a long day begins. I’m in meetings all Thursday here in Houston as the 100 Year Starship Symposium gets going, having slept well last night on the gigantic bed provided by the Hyatt. The travel day was uneventful. I had decided to make this a non-digital flight as much as possible so as to get through security with less difficulty. That meant the laptop went in a checked bag, the Kindle stayed home, and for the plane I took an actual book, one with pages that you turn by hand, a cover, and an index in place of a search engine. So much for my plans – everything was going great until a couple of coins in my pocket set off the alarms and I got patted down.
Image: Yesterday afternoon’s view from my room. The Hyatt Regency has a rotating restaurant on its 31st floor. Despite Calvin Trillin’s famous exhortation never to eat in a restaurant that rotates, I found the food quite good, including a spectacular glass of Cloudy Bay Sauvignon Blanc from New Zealand. Nice view, too.
I’m seeing articles about the symposium popping up here and there in the media, maybe not so many as last year, although I haven’t had the chance to quantify it yet. One common misapprehension continues to be what the 100 Year Starship organization is really about. The Daily Mail refers to a “dramatic plan to transport humans beyond the solar system within 100 years,” but who knows whether starships, if we learn how to build them, will carry humans or sophisticated artificial intelligence? Some people I’ve spoken with think the plan is to reach another star by 2112, but if we were going to get to another planetary system in 100 years, we would be launching the starship about now, and we obviously don’t have the capability of doing that. A lot of education has to be part of any starship organization, given the confusion about actual distances and how long it will take to understand the solutions.
I’m told that Kelvin Long’s Interstellar Studies Institute is about to go online, clearly timed for the 100 Year Starship Symposium, and that may help generate a bit of extra buzz as well. I hope that whatever comes out of the press attention to this event is part of a gradual process of getting interstellar ideas out to the public in a way that’s both inspirational but also realistic. Yes, there are ways using known physics that an interstellar journey can be done, assuming we develop the technologies that look theoretically possible and the infrastructure to support them. We’re nowhere near that level now, though maybe we can be ready to launch a star mission in a hundred years. Maybe. An email I got just before leaving lays out the level of misunderstanding: “We’re already going to Pluto,” says the writer. “ How much harder can it be to go to a star?”
I could write a whole book in answer to that question. Wait — I already have…
An email I got just before leaving lays out the level of misunderstanding: “We’re already going to Pluto,” says the writer. “ How much harder can it be to go to a star?”
I could write a whole book in answer to that question. Wait — I already have…
—
Absolutely classic :)
Have fun, Paul. Very much looking forward to your posts from this Symposium.
Interstellar Starship Meeting Warps Into Houston This Week
updated 9/13/2012 11:36:44 AM ET 2012-09-13 T 15:36:44
HOUSTON — Celebrities, scientists, artists and astronauts are converging here Thursday to discuss what it will take to send a spaceship to another star.
The second annual 100-Year Starship Symposium is kicking off, under the auspices of the Defense Advanced Research Projects Agency (DARPA), to ponder the technology, psychology, sociology and economics of interstellar spaceflight.
Notable attendees include actors Nichelle Nichols and LeVar Burton, who appeared on television’s “Star Trek” and “Star Trek: The Next Generation,” respectively; space journalist Miles O’Brien; alien-hunting astronomer Jill Tarter, a co-founder of the SETI (Search for Extraterrestrial Intelligence) Institute; and Johnnetta Cole, director of the Smithsonian National Museum of African Art.
Former President Bill Clinton is backing the conference as its honorary chairman, and the symposium chairwoman is former astronaut Mae Jemison, the first African American woman to travel to space.
Full article here:
http://www.msnbc.msn.com/id/49019439/ns/technology_and_science-space/
“I took an actual book, one with pages that you turn by hand, a cover, and an index in place of a search engine.”
What are those? Those things you call “actual books”? I wonder if any such weighty, combustible relics will be carried on the first interstellar starship ever to transport humans.
How did you arrive at this curious assessment? The travel time to another star system with current technology seems to be on the order of thousands of years, not a hundred years, even using solar sails or next-generation nuclear-electric rockets. If a starship were setting out to Alpha C right now with an arrival date of 2012, it would need to travel 5% of C. We can’t do that with our current technology.
If, however, we built propulsion systems capable of 20% C, the launch date for the “Alpha C by 2112 or bust!!” starship could be bumped up to 2087. Of course, most scientists would agree that it is highly unlikely we will have such starship by the 2080s, even if they think that it is theoretically possible to built such a craft. On the other hand, if the gravitron polarity generator, space warp engine, or jump drive is invented around the middle of 21st century as promised by SF stories, all bets are off as to when we may launch- or arrive.
Most likely, of course, we will be lucky to launch a starship of some sort in the 22nd century, let alone arrive in the early 2110s. It depends on when these technologies are developed and how fast we can travel- in which it is likely to be later than we’d like and slower then we’d like, but your estimate seems to vastly overestimate our current capabilities while placing a speed limit around 5% C- which doesn’t make much sense to me.
Clearly, any functioning interstellar institute needs to work on providing educational materials for the public. Sometimes it is difficult to realize how much confusion exists as to the actual magnitude of interstellar distances and how long it may take to create the technologies for crossing them.
Humans to Alpha Centauri/Pluto robotic flyby probe : How much harder could it be?
Velocity x 1000 = energy x 1,000,000
x Crewed spaceflight duration 100 x longer than the longest space station missions
x Mass of vehicle 100 x anything we have orbited
I reckon it to be merely 10,000,000,000 times harder
Hi Paul,
that is not the correct web site link for the Institute.
This is it:
http://www.i4is.org/
it should be live later today.
thanks
Kelvin
Hi Paul,
I’d be interested to know if anyone is giving a talk on how to place a large starship (500m long?) prebuilt on the Earth’s surface into orbit. There seems to be plenty of papers on how to get a starship to star systems lightyears away however none that deal with the more pressing problem on how to get big hardware 150km above the surface without using chemical rockets or space elevators. Note that this would also solve the problem of getting hardware from orbit back ground without smashing it into bits and pieces.
Cheers, Paul.
Re Kelvin Long’s Institute, the correct address is indeed:
http://www.i4is.org/
Sorry for the mixup, Kelvin!
Paul Titze said on September 14, 2012 at 2:01:
“I’d be interested to know if anyone is giving a talk on how to place a large starship (500m long?) prebuilt on the Earth’s surface into orbit. There seems to be plenty of papers on how to get a starship to star systems lightyears away however none that deal with the more pressing problem on how to get big hardware 150km above the surface without using chemical rockets or space elevators. Note that this would also solve the problem of getting hardware from orbit back ground without smashing it into bits and pieces.”
Wouldn’t it make more sense to build everything in space? By the time we do have an actual interstellar program going, we should also have some kind of permanent presence in space, which I will assume includes access to building resources and construction facilities.
Let us not make our starship plans even more difficult and stretched out in time by adding space elevators and the like into the mix. The idea of mining helium-3 in Jupiter’s atmosphere was one of the roadblocks for Daedalus as far as I am concerned to use an example. And oh yeah, the lack of an actual working fusion reactor didn’t help, either.
Joy,
I appreciate your calculations. Well done.
Marc
Ljk wrote:
“Wouldn’t it make more sense to build everything in space? By the time we do have an actual interstellar program going, we should also have some kind of permanent presence in space, which I will assume includes access to building resources and construction facilities.”
It’s a lot cheaper and safer to build spacecraft on the surface where there are lots of people/resources rather then build things in space if given the option. All depends if there’s a solution to my original question.
Cheers, Paul.
Joy said: “I reckon it to be merely 10,000,000,000 times harder.”
Given determination, patience and the resources of the Solar System, that shouldn’t be too much of a problem:
Present-day human population x 1,000,000 — this is John S. Lewis’s estimate (in his classic book Mining the Sky) for the population of a developed Asteroid Belt. Say 3% growth for 470 years.
Present-day wealth per person x 10,000 — this is 2% growth for 465 years.
Multiply these together to get an economy 10^10 times more powerful than that of today, thanks to the power of that fashionable bête noire, exponential growth.
Taking the resource of solar power (380 x 10^12 TW) as indicative of our actual physical room for growth (and remembering that the biggest growth factor for a starship identified by Joy was propulsion energy), an economy well over a trillion times larger than at present is conceivable (asteroidal matter for space colony construction can be expanded if necessary by dismantling small moons). Thus we would still at that point possess only 1% of the ultimate economic power of a fully developed interplanetary civilisation.
About the year 2500, therefore, Joy’s growth criterion could be met, assuming continued faith in material progress and success in finessing our way through all the stresses and strains of growth.
As for mining Jovian helium-3, ljk, your only problem as you click to order will be whether or not you want it delivered gift-wrapped…
Stephen
Oxford, UK
Stephen & Joy,
Would love to see some sort of timeline versus thresholds for these, including uncertainty bands. Paper?
Marc
Marc, my double paper on the subject has been chugging through the JBIS system for the past ten months or so, ever since I presented at the BIS Worldships symposium a year ago. I’ve not done uncertainty bands, just a sort of sample scenario with discussion of what seem to me to be important issues, and recognition that this is all really speculative and dependent upon factors over which nobody has any control. Would be interesting to have more dialogue with Joy, who often has a interestingly skeptical take.
Uncertainty bands: what can I say? Maybe you can make sense of this idea. We can’t really quantify the probability of unique future events. Basically the downside is that civilisation collapses and we’re all dead, and the upside is that someone invents warp drive and we colonise the Galaxy by the end of the millennium. As I say, I can only sketch out a scenario and hope that it illuminates some of the strategic issues.
Stephen
Paul Titze said on September 15, 2012 at 1:09:
Ljk wrote:
“Wouldn’t it make more sense to build everything in space? By the time we do have an actual interstellar program going, we should also have some kind of permanent presence in space, which I will assume includes access to building resources and construction facilities.”
It’s a lot cheaper and safer to build spacecraft on the surface where there are lots of people/resources rather then build things in space if given the option. All depends if there’s a solution to my original question.
LJK replies:
If you want to get lots of resources off Earth to build a starship, we could go with our current chemical rockets, but you will probably need a lot of them. I suppose that would boost (pun intended) our space industry, but where will the money and resources for all those launches come from?
Please do not even bring up a space elevator. That requires materials which do not yet exist as just one of the many issues with the concept. Waiting for a space elevator to happen as part of the process will only push out the date of when a starship could become reality.
In the end, it will make more sense to build our ships in space. Bountiful resources that are easy to access are out there literally just floating around. You won’t have to get out of Earth’s gravity well once you are working in space. It will actually be cheaper to do this up there than down here. And as for safety, well, if you are going to worry about that we might as well not do anything. Hardly any major construction project ever happens without a few human losses. I am not trying to be cold here, I am being realistic if you want an actual starship or two built, not to mention the rest of the infrastructure that needs to go along with it. Our culture has become absurdly risk-adverse these days; that is one reason among many why we aren’t even back on the Moon or on to Mars with actual human beings.
Let’s face it, starship or not, most everyone here would agree we need to be a permanently embedded space culture. How else can we do this if we have to rely on resources and launches strictly from Earth? Not realistic or sustaining at all.
Astronist said on September 15, 2012 at 5:15:
“As for mining Jovian helium-3, ljk, your only problem as you click to order will be whether or not you want it delivered gift-wrapped…”
Have you or anyone else figured out just what it would take to actually mine helium-3 from the atmosphere of Jupiter? This is one thing that really annoys me about some of the discussions regarding starships. Minor details about aspects that could actually happen either now or in the near future are picked apart to death, while fantastical ideas that are just this side of magic are assumed plausible down the road with a lot of hand waving.
We could start building an Orion fission propulsion starship NOW if we really wanted to. No space elevators, no warp drive, no dilithium crystals, and no need to go 400 million miles to Jupiter and back to get the fuel for a propulsion method that has yet to last more than a few seconds at best.
I sincerely hope this latest symposium had some good papers with practical solutions that could be done now or very soon. I also hope we will see these papers and videos sooner than last year’s symposium. Otherwise these events will turn into mere academic conferences for the next fifty years. Or worse, variations of a Star Trek convention.
Stephen, Joy;
Check to see if Paul will facilitate email introductions if both of you want to collaborate.
As for me, I want to hand off the baton on these estimates to others, since I’ve already been down that path and am moving onto the next questions.
Regarding how to determine uncertainty bands on limited data: For all those parts of your assessment were you use data, check more than one source for those values. Ideally you want to span the advocates and opponents to get high and low values to bracket your uncertainty. Although this is NOT completely satisfactory, it is a start. From there, you just deal with uncertainties as they are normally calculated. If your assessments are NOT based on data, then they are not “assessments.” In that case, they are more like hypothetical scenarios that could still be useful if it is understood where the facts leave off and the speculation begins.
I really encourage you and others to look into such things and find what data does exist.
Regarding missing or weak links in system/mission analysis…
(1)
When folks advocate for a particular propulsion/power/vehicle choice, it is typical that the following details are inadequately addressed:
1.1 – System level integration, where one cannot use the ‘best’ values for all the parts of the system (e.g. J/kg, W/kg). For more realistic system analysis, include the uncertainty ranges with those estimates of the sub-component characteristics. Also make sure the flag any correlated values, were raising one value will lower another.
1.2 – Thermal management, estimating how much unusable energy will result from the inefficiencies in the system, and what you will need to reject that waste heat to space.
1.3 – Magnetic nozzle – realistic performance within the bounds of engineering.
1.4 – Scale and time-line to build the space infrastructure required to be build and fuel the starship.
1.5 – Pointing accuracy limits for optical com and power beaming
(2)
Determining the weak links from conducting honest system-level assessments is NOT a BAD thing! Such determinations show the community which technical areas need more attention… those incremental research steps to strengthen those weak links.
If one is just doing advocacy, however, then yes, they don’t like to admit weak links because it makes their pet ideas look bad. But progress is not about sales pitches. To make real progress, we have to be honest about those weak links – and fix them.
ljk, thanks. However, I’m not sure I understand where you’re coming from, as your reply to Paul Titze seems to be assuming a space economy, while your reply to me seems to want to bypass a space economy altogether.
My point is that the very large energy demand of a manned interstellar vehicle (a multiple of current annual global industrial production) requires a well-established space economy. Maybe this will be based on nuclear fusion, and maybe mining helium-3 (more realistically from Uranus, as described in more detail by John S. Lewis, rather than from Jupiter), or maybe on solar power converted to microwave beams or to antimatter. I believe we’ve disagreed before in comments here about the possibility of building any kind of starship right now using nuclear fission.
Marc, thanks, I think I’m still at the hypothetical scenarios stage, but will look and see if I can re-emphasise the uncertainties while preserving something of value!
Stephen
LJK:
Yes, this is true. No matter how big, the space ship is likely to be much less massive than the collection of all the factories that will be required to produce it and its components, subcomponents, etc. from raw materials. So better to build it on Earth, launch it in pieces, and merely assemble it in space. Ikea style :-)
On the other hand, we DO want to build all those factories in space, eventually, for all sorts of non-starship reasons. So, it all depends which we want first: The starship, or the complete industrial infrastructure in space. And “some kind of permanent presence” is not enough. It has to be a complete industrial infrastructure capable of producing the bulk of the starship without recourse to Earthside factories.