Every few weekends as we move toward the March 5 deadline for submission of abstracts to the next International Astronautical Congress, I’ll re-run this call for papers that I originally published in December. The Tau Zero Foundation hopes to energize discussion of FOCAL in the astronautical community and create a growing set of papers analyzing aspects of the mission from propulsion to communications, leading to a formal mission proposal. We hope anyone interested in furthering this work at the coming IAC in Prague will consider submitting a paper.
The Tau Zero Foundation is announcing a call for papers related to the FOCAL mission. The venue: The 61st International Astronautical Congress in Prague, which convenes on the 27th of September, 2010 and runs to October 1. Specifically, we are looking for papers for session D4.2, “Interstellar Precursor Missions,” whose focus is “…missions that significantly expand science — using existing and emerging power and propulsion technologies.”
Long-time Centauri Dreams readers are well aware of Claudio Maccone’s FOCAL concept, a mission to the Sun’s gravitational lens at 550 AU and beyond. FOCAL would make possible studies of astronomical objects at unprecedented magnifications. The electromagnetic radiation from an object occulted by the Sun at 550 AU (i.e., on the other side of the Sun from the spacecraft), would be amplified by 108. Moreover, whereas with an optical lens light diverges after the focus, light focused by the Sun’s gravitational lens stays fixed along the focal axis. Every point along the straight trajectory beyond 550 AU remains a focal point for any vehicle we put on this trajectory.
Imagine, then, two possible FOCAL mission targets. The first option would be to launch the probe toward the heliopause in the place where it is closest to the Sun, the direction of the incoming interstellar wind. This would allow useful studies of the heliosphere itself, but the deeper goal would be to reach 763 AU, the place where the cosmic microwave background will be focused by the Sun’s gravitational lens upon the spacecraft. As Maccone has shown, detecting lower frequencies pushes the focus further from the Sun — the focal distance, in other words, changes as a result of frequency.
We’ve learned how valuable information about the CMB is to cosmologists. Now imagine the result of examining the CMB with the vast magnifications possible through a FOCAL probe. But a second choice is also available. FOCAL could be optimized for close study of the Alpha Centauri stars, especially if current efforts pay off and we do find interesting planets around Centauri A or B. Centauri demands a different kind of mission because it is far from the ecliptic. The flight path is problematic because the Centauri stars are so close, requiring ion propulsion to achieve the necessary spiral trajectory.
Addendum: So many readers have mentioned Dr. Maccone’s recent SETI Institute lecture that I want to go ahead and link to it now, although I was planning a separate piece on it next week. When I met with Claudio recently in Austin, he was getting ready to leave for the West Coast to make this presentation before concluding his US trip and heading back to Italy. What a pleasure it was to talk to him at leisure about FOCAL.
But all of these are matters that now need to be taken to the next step at the International Astronautical Congress, where they will gain further visibility in the scientific and industrial community. Papers are solicited on the propulsion problem — is a solar sail optimal? Nuclear-electric? Perhaps VASIMR? We also hope for submissions on the scientific return from a FOCAL mission, on telecommunications technologies, on computing requirements, and perhaps on the social and cultural value of a concept that would take human technologies further from the Sun than any previous missions.
Image: The FOCAL mission as currently envisioned by Claudio Maccone. The image is taken from the cover of his book Deep Space Flight and Communications: Exploiting the Sun as a Gravitational Lens (Springer/Praxis, 2009), and shows two 12-meter antennae operating through a tether which is gradually released, allowing a field of view much larger than that offered by a single antenna. Credit: Claudio Maccone/Springer.
The preliminary program for the Prague IAC has already been posted. The deadline for submitting abstracts to the Congress is 5 March 2010. Let me quote from the IAC documentation on what the criteria for selection will be:
Submitted abstracts will be evaluated by the Session Chairs on the basis of technical quality. Any relevance to the Congress main theme of ‘Space for human benefit and exploration’ will be considered as an advantage.
The criteria for the selection will be defined according to the following specifications:
* Abstracts should specify: purpose, methodology, results and conclusions.
* Abstracts should indicate that substantive technical and/or programmatic content is included
* Abstracts should clearly indicate that the material is new and original; explain why and how.
* Prospective authors should certify that the paper was not presented at a previous meeting and that financing and attendance of an author at the respective IAC at Prague to present the paper is assured.
Full information about the meeting and the submission process is available through the official Call for Papers & Registration of Interest.