The stability of a light sail riding on a laser beam is analyzed both analytically and numerically. Conical sails on Gaussian beams, which have been studied in the past, are shown to be unstable in general. A new architecture for a passively stable sail and beam configuration is proposed. The novel spherical shell sail design is capable of “beam riding” without the need for active feedback control. Full three-dimensional ray-tracing simulations are performed to verify our analytical results.

Arxiv — Stability of a Light Sail Riding on a Laser Beam (6 pages by Zachary Manchester, Abraham Loeb of Harvard)

President Obama said Tuesday that he wants private companies to help send humans to Mars by the 2030s.

Obama first said in 2010 he wanted to send astronauts “to orbit Mars and return them safely to Earth” by the mid-2030s with “a landing on Mars” to follow. In that speech at the Kennedy Space Center, Obama added that he expected to see such a landing in his lifetime.

In an opinion article Tuesday on CNN.com, Obama said private companies would be key to those lofty goals.

The European Space Agency has teamed up with Russia’s Roscosmos program to land a spacecraft on Mars on Wednesday, October 19.

If they stick the landing, they’ll join NASA as the only space agencies in history to successfully land a spacecraft on Mars. And that will only be the beginning — the lander will then start a whole new quest to search for signs of life on the Red Planet.

If the landing is a success, it will actually see the agencies put one spacecraft up into Mars’s atmosphere, and one onto its surface, giving scientists a rare opportunity to record conditions above and below the planet simultaneously.

China is already well on the way to establishing its own version of America’s GPS network with its Beidou satellite constellation, but now it is seeking to take navigation and timing to stellar levels.

In November China will launch the X-ray pulsar navigation satellite — XPNAV-1 — a satellite that will conduct the world’s first test of the possibilities of using the regular emission of X-ray signals from pulsars for spacecraft navigation.

The spacecraft will attempt to triangulate its position relative to the Sun using the highly regular emissions from pulsars.

There has been a lot of talk recently about reusable rockets and asteroid mining making space travel cheaper, but a proposed idea for a maglev train into space might be the real answer.

Using existing maglev technology, the Startram project proposes to launch people and cargo down a 1,000-mile long tunnel 12 miles high at 20,000 mph using a superconducting cable.

The idea sounds far fetched, but it’s being pitched by some really smart people. Dr. James Powell co-invented superconducting maglev trains and Dr. George Maise is an aerospace engineer; they believe the train into space is the answer that could make interplanetary travel possible.

The plan is heavy on ambition, light on specifics.