The paper itself provides much more insight into the actual physics behind this [1]. The article doesn't really do the paper justice in my mind, based on my knowledge of the subject matter (although I appreciate the intent of providing an accessible means to introduce the topic).<p>I wrote my MSc thesis on weak capture trajectories and the concept of the Weak Stability Boundary [2] that was introduced by Ed Belbruno. It's a fantastic aspect of the gravitational 3-body problem and has been probed from a number of different perspectives over the last two decades, including tying in the phenomenon of weak/ballistic capture into our understanding of the structure of invariant manifolds and the periodic orbits about the Lagrange libration points.<p>Disclaimer: Francesco is my boss but I haven't spoken to him yet about the paper.<p>[1] <a href="http://arxiv.org/pdf/1410.8856v1.pdf" rel="nofollow">http://arxiv.org/pdf/1410.8856v1.pdf</a><p>[2] <a href="http://en.wikipedia.org/wiki/Low-energy_transfer" rel="nofollow">http://en.wikipedia.org/wiki/Low-energy_transfer</a>
I hate all the fluff in this article.<p>TL;DR: Ballistic Capture aka "Low-energy transfer" is being rekindled by NASA, Boeing, Belbruno, Topputo and colleagues. Fly the spacecraft ahead of Mars in formation of the planets orbit relative to the sun allowing gravity to gradually slow the spacecraft down. This saves on fuel/weight for entering orbit at high velocity.
Buzz Aldrin is very passionate about colonizing Mars [1]. He says there are two big things that have to be accomplished before we can colonize Mars. The first is to train astronauts to live in a confined isolated space for 260 days (the length of a journey to Mars) [2]. This alternative journey trajectory increases the 260 days.<p>The second is harder: We need to go to Mars at least three times and bring back the men and women successfully. Once is not enough. Three proves we've mastered the engineering, financial, physical, and physiological aspects.<p>[1] <a href="http://www.pbs.org/wgbh/nova/space/aldrin-mars-au.html" rel="nofollow">http://www.pbs.org/wgbh/nova/space/aldrin-mars-au.html</a><p>[2] <a href="http://www.guardian.co.uk/science/2010/jun/03/mock-mission-mars-moscow-hangar" rel="nofollow">http://www.guardian.co.uk/science/2010/jun/03/mock-mission-m...</a>
How much of a given total cost of a launch to Mars is the fuel? According to the article, it shaves 25% off the fuel costs - but what percentage of the total is that, let's say, for the past few missions?<p>It seems that the bigger advantage of this is adding a few months but doing away with waiting for a launch window. Definitely great for equipment, though it would put two months' worth of extra stress on actual human travelers.
My KSP-fu is failing me here... how is it possible to match Mars' circular solar orbit at a slower velocity? Wouldn't a different velocity imply a different orbital distance from the sun?
<a href="https://en.wikipedia.org/wiki/Nuclear_pulse_propulsion" rel="nofollow">https://en.wikipedia.org/wiki/Nuclear_pulse_propulsion</a><p>With nuclear pulse propulsion, we could send a craft to Mars in 2-3 weeks, safely, any time, and on the cheap.<p>The mass that can be transported is quite enormous, so we could piecemeal launch the components of a huge habitat and vast amounts of supplies into an outer orbit of Earth, robotically load them onto the pulse ship, and then shoot that baby to Mars.<p>Probably the slowest part of the plan would be launching the stuff into orbit. They scrubbed the idea of launching using nuclear pulse propulsion because of the dangers of radioactive fallout. Too bad, because that would have made things even simpler.
Web design tip (that I just made up). If you're going to have an annoying, large header bar appear above the text when the user scrolls, don't put a drop-shadow under it. It looks like an object is hiding the text, which it is, but is very distracting compared to a flat border.
For a fun (fictional) take about life on Mars, I'd recommend reading The Martian by Andy Weir ( amazon link: <a href="http://www.amazon.com/The-Martian-Novel-Andy-Weir-ebook/dp/B00EMXBDMA" rel="nofollow">http://www.amazon.com/The-Martian-Novel-Andy-Weir-ebook/dp/B...</a> ). The book was a wild read, and does a tremendous job showing the myriad difficulties humanity must overcome in order to colonize Mars.
What this really means is that cargo deliveries to Mars can be made any time in the orbital cycle; it's not necessary to wait for a close approach. The trip takes a few months longer, but can be started at any time. Useful if there are ever any significant operations on Mars.
I was surprised that they described a Hohmann Transfer as a "brute force approach to attaining orbit." I would have described it as the non brute-force approach to changing orbits.
Maybe now there will be a Mars X-Prize after we complete the Lunar X-Prize: <a href="http://lunar.xprize.org/" rel="nofollow">http://lunar.xprize.org/</a>