Propulsion Book Discussion Available

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Give a look, and then a listen, to David Livingston’s August 3rd Space Show. Livingston talked to Tau Zero founder Marc Millis and Eric Davis (Institute for Advanced Studies at Austin) about the recently published Frontiers of Propulsion Science, calling it “the ultimate research and reference book to have for advanced and out-of-the-box space propulsion science” and adding:

“As you will hear me say over and over again, this is a must own and a must read book. It is also a very valuable research and reference book for anyone wanting to know propulsion and physics facts regarding space travel and related issues.”

Knowing how much time and effort Marc and Eric spent coordinating the many contributions from leading authorities that went into this book, it’s a pleasure to see Frontiers of Propulsion Science achieving this kind of acclaim. At 739 pages and stuffed with technical and scientific papers aimed at scientists and university students, the book is an exhaustive treatment of where we stand today and where we’re going.

Cryovolcanism on Titan?

We’ve used radar imaging to get a good look at about a third of Titan’s surface, thanks to the phenomenal Cassini orbiter, examining a geologically young surface with numerous lakes of liquid hydrocarbons (such as methane and ethane) in the northern latitudes, few impact craters and chains of mountains. But word at the IAU General Assembly, meeting in Rio de Janeiro, is that another instrument aboard Cassini — the Visual and Infrared Mapping Spectrometer (VIMS) — has detected evidence of volcanic activity in the form of cryovolcanoes on the distant moon.

The focus is on an area called the Hotei Regio, a region whose variable infrared signature suggests a cycle of ammonia frost appearing and disappearing. The implication is that ammonia from Titan’s interior is being delivered to the surface and subsequently dissipating or being covered. Radar imaging of the area shows structures that resemble terrestrial volcanoes, the apparent mechanism for the ammonia deposition (more in this IAU news release).

Here’s Robert Nelson (JPL), who discussed the matter in Rio:

“These new results are the next advance in this exploration process. The images provide further evidence suggesting that cryovolcanism has deposited ammonia onto Titan’s surface. It has not escaped our attention that ammonia, in association with methane and nitrogen, the principal species of Titan’s atmosphere, closely replicates the environment at the time that life first emerged on Earth. One exciting question is whether Titan’s chemical processes today support a prebiotic chemistry similar to that under which life evolved on Earth?”

Related: Imagine what a robotic rover could do on Titan. Giancarlo Genta, in the second of his presentations at the recent Aosta conference, discussed the design parameters of such a rover, one that included the capability of crossing terrain as well as sailing across ethane lakes. Two papers by Dr. Genta on this topic should be appearing in Acta Astronautica in coming months, both now in Proceedings of the Sixth IAA Symposium on Realistic Near-Term Advanced Scientific Space Missions, Aosta Italy (2009). They are “A Small Robotic Rover for Titan Exploration: Part 1: General Layout” (pp. 105-110 in the proceedings), and “Part 2: Strategies for Trajectory Control,” pp. 111-116.

Update from Denver Propulsion Conference

Another report from the 45th Joint Propulsion Conference & Exhibit in Denver focuses on beamed energy propulsion, in this case ground-based laser systems that can heat fuels like hydrogen and lighten the mass of spacecraft. Leik Myrabo (Rensselaer Polytechnic Institute) has been working this turf for some time. The founder of Lightcraft Technologies is working under a grant from the US Air Force to use laser methods for satellite launches. Conveniently in terms of the conference, he’s in Brazil testing these ideas in collaboration with the Brazilian air force.

Myrabo thinks advances in energy-beaming technology in recent years have brought these systems closer to reality, but the article gives a nod to the skeptics:

Kevin Johnson, a space exploration and spacecraft propulsion manager at Lockheed Martin Space Systems in Denver, for example, expresses concern about the potential for atmospheric interference with the beam. Greg McAllister, a senior staff propulsion engineer also at Lockheed Martin, agrees and says that an energy source powerful enough to propel a rocket could also burn it up. (McAllister is presenting a paper at the conference on testing the pulse throttle thrusters used for the Mars Phoenix mission.)

Johnson says that while the system could generate enough power from a ground-based station and reduce costs, it is “20-plus years” from being feasible.

Twittering in Case of Emergency

Some of you are aware of the software problems that caused Monday’s Centauri Dreams post to be delayed for a day. Until I could fix the problem, I had no way to post on the site itself, which made Twitter a useful venue. In the event of future glitches, you may want to check the Centauri Dreams Twitter feed, where I’ll update problematic situations like Monday’s. I had no idea when Monday started that I would spend most of the day researching a glitch that came out of the blue. Suffice it to say that repairing the site internals on a rush basis can play havoc with anyone’s schedule. Let’s hope it doesn’t happen again, but knowing the Net, anything’s possible.

Addendum: Well that’s aggravating. Just after I published this nod to Twitter, I tried to use it to comment on the incoming Kepler news. You can follow the news conference (it’s now 1425 EDT) here. The Twitter site is up but it won’t take new posts…

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