Tuesday, March 29, 2011

One-Tenth Light Speed and Jordin Kare

In what is the Lunar Colonization/Space Exploration part of my cycle I was going to discuss Bigelow Aerospace but an article at Centauri Dreams (currently hosting The Carnival of Space #190) by Paul Gilster caught my eye, regarding another dream of many of us: Interstellar Exploration.

(Don't worry Pat Ballew, that means we cycle to Math tomorrow :-)  )

As Paul writes in the article "Pedal to the Metal", here :

It’s fun to juggle these numbers even as we think about how far we have to go before an interstellar probe becomes a possibility. If the goal is to reach Alpha Centauri with a mission lasting, say, forty years, then we need a tenth of lightspeed, or roughly 30,000 kilometers per second.

[ .... 17.05 kilometers per second, which is faster than any of our outward bound spacecraft but would take well over 70,000 years to reach Alpha Centauri, assuming Voyager 1 were pointed in that direction. New Horizons is currently making 15.73 kilometers per second on its way to a Pluto/Charon flyby in July of 2015, impressive but not the kind of speed that would get us to interstellar probe territory.

Interestingly, the fastest spacecraft ever built weren’t headed out of the Solar System at all, but in toward the Sun. The Helios probes were West German vehicles launched by NASA, one in 1974, the other in 1976, producing successful missions to study conditions close to the Sun for a period of over ten years. The orbits of these two craft were highly elliptical, and at closest approach to the Sun, each reached speeds in the range of 70 kilometers per second. Helios II, marginally faster, lays claim to being the fastest man-made object in history.]

That makes .10c a figure of distinction, because it creates a mission that can be built, flown and studied to completion by the same team.

In the replies section, reader Adam says :

For just 30 GW of in-space laser power, Jordin Kare’s Sail-Beam can push a 1 ton probe to 0.1c. Whether we can give a 1 ton probe enough power to do anything useful at Alpha Centauri when it gets there is a whole other question.

Who the heck is Jordin Kare? I must confess my membership papers in the Interstellar community are dusty and unused of late, as I feel I have bigger fish to fry at the moment, but still, it's intriguing.

I do recall having similar yet different thoughts in my Railroad to the Stars article of this past December, but Jordin is a Professional in the field and I think we should listen to him first:

Jordin Kare

Jordin Kare (born 1956) is a physicist and aerospace engineer known for his research on laser propulsion. In particular, he was responsible for Mockingbird, a conceptual design for an extremely small (75 kg dry mass) reusable launch vehicle, and was involved in the Clementine lunar mapping mission.[2][3] Kare is also known as developer of the Sailbeam interstellar propulsion concept and, in the science fiction fan community, as a composer, performer and recording artist of filk music parodies.


He received his B.S. in Electrical Engineering and Physics from the Massachusetts Institute of Technology in 1978 and Ph.D. in Astrophysics from University of California, Berkeley in 1984.[2][4] Kare is the brother of Susan Kare, designer of the fonts and icons of the original Apple Macintosh user interface.[5][6]


Kare worked for many years at Lawrence Livermore National Laboratory. In 1996, he left LLNL and, after working briefly for a small space-related startup company, became an independent consultant specializing in advanced space system design in 1997,[4] and started his own company.[5] He is a leading advocate of laser propulsion for space launch and in-space propulsion. He organized a 1986 Workshop on Laser Propulsion at LLNL and later led a development program for ground to orbit laser launch supported by SDIO. He has received a NASA Institute for Advanced Concepts grant to study a near-term form of laser launch using arrays of relatively low powered lasers.[4][7][8][9] He is a team member of LaserMotive,[10] a laser power beaming entrant in the Elevator:2010 Beam Power Challenge.


Kare initially presented the concept of a SailBeam Boosted Magsail in a report prepared for NASA’s Institute for Advanced Concepts called “High-Acceleration Micro-Scale Laser Sails for Interstellar Propulsion”. A key idea is that if you accelerate vast numbers of tiny sails rather than one enormous one, you can bring the same amount of mass to high speeds with a less complex optical system. Unlike particle beam propulsion where the beam disperses as it travels, a stream of low-mass microsails is not limited by such diffraction. Using dielectric rather than metal sails, you can also accelerate the sails much closer to their power source. The stream of microsails then becomes a source of propulsion to a starship as particle beams mounted on the starship vaporize the incoming sails into plasma.

Filk music and science fiction

Kare is also known as a science fiction fan and filksinger. He has been a regular attendee and program participant at science fiction conventions since 1975.[1][3] He was an editor of The Westerfilk Collection: Songs of Fantasy and Science Fiction, an important filksong collection, and later a partner in Off Centaur Publications, the first commercial publisher specializing in filk songbooks and recordings.[1][11][12] An astrophysicist character with his name appears in War of Honor, a military science fiction novel in the Honor Harrington series by David Weber.



  • Self-published two albums of his songs, Fire in the Sky (1991; distributed by Wail Songs) and Parody Violation: Jordin Kare Straight and Twisted (2000)[1]



  1. ^ a b c d Filk biography in CopperCon 22 Filking News
  2. ^ a b Jordin Kare. "Intersection Science Programme Participants: Jordin Kare". Intersection Science Programme Participants. John Bray. http://www.johnbray.org.uk/intersection/people.html#Jordin%20Kare. Retrieved 2007-08-13. 
  3. ^ a b Capclave 2005: Confirmed Program Participants: Jordin Kare
  4. ^ a b c "Space Access Update #93". Space Access Society. 2000-04-13. http://www.space-access.org/updates/sau93.html. Retrieved 2007-08-13. 
  5. ^ a b "The Monell Connection, Winter 2003" (PDF). Monell Chemical Senses Center. 2003. pp. 9. http://www.monell.org/Newsletters/Monell_Fall03.pdf. Retrieved 2007-08-13. 
  6. ^ Alex Soojung-Kim Pang (2001-02-19). "Interview with Susan Kare". Making the Macintosh. Stanford University. http://library.stanford.edu/mac/primary/interviews/kare/index.html. Retrieved 2007-08-13. 
  7. ^ Jordin Kare Laser Launch Bibliography (1986-1992)
  8. ^ Dr. Jordin T. Kare (2004-05-18). "Modular Laser Launch Architecture: Analysis and Beam Module Design. Final Report." (PDF). Kare Technical Consulting. http://www.niac.usra.edu/files/studies/final_report/897Kare.pdf. Retrieved 2007-08-12. 
  9. ^ http://www.foxnews.com/scitech/2011/01/25/nasa-exploring-lasers-beams-zap-ro ckets-outer-space/
  10. ^ "LaserMotive Team Bios". http://www.lasermotive.com/blog/?page_id=6. Retrieved 2007-09-06. 
  11. ^ Jordin Kare. "Filk music?". Sing Out!. http://www.interfilk.org/interfilk/singout.htm. Retrieved 2007-08-13. 
  12. ^ "Jordin Kare". Fan Gallery. SCIFI Inc.. http://www.scifiinc.net/scifiinc/gallery/bio/Kare,_Jordin.htm. Retrieved 2007-08-16. 
  13. ^ Hertz Foundation. "Hertz Foundation Fellows". http://www.hertzfoundation.org/dx/fellowships/fellows.aspx. Retrieved 23 January 2011. 

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