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starship-design: Solar sails and mission structure

>Date: Mon, 11 Nov 1996 18:30:29 -0500
>From: Nick Tosh <101765.2200@compuserve.com>
>Subject: Solar sails and mission structure
>To: "[unknown]" <jim@bogie2.bio.purdue.edu>,
>        "[unknown]" <rddesign@wolfenet.com>, "[unknown]" <sl0c8@cc.usu.edu>,
>        "[unknown]" <DotarSojat@aol.com>, "[unknown]" <mkshp@ionet.net>,
>        Phillip Bakelaar <pbakelaar@exit109.com>,
>        "Kevin C. Houston" <hous0042@maroon.tc.umn.edu>,
>        Zenon Kulpa <zkulpa@zmit1.ippt.gov.pl>,
>        David Levine <David@interworld.com>,
>        Timothy van der Linden <T.L.G.vanderLinden@student.utwente.nl>,
>        "L. Clayton Parker" <lparker@cacaphony.net>,
>        Kelly Starks <kgstar@most.fw.hac.com>,
>        Steve VanDevender <stevev@efn.org>
>Hello again everybody.
>Sorry I'm so slow to contribute, but I'm very busy working for my A-levels
>- British equivilent of American high school graduation, only harder ;) and
>preparing for an admissions interview for Cambridge University (British
>equivilent of Harvard, only... no I'm not gonna say that). I'm afraid I'll
>be a bit out of phase with everyone else for a while.
>Thanks everyone for the mailing list info, I've just sent my subscription
>mail. It doesn't send everything as one big mail does it? It's just that my
>family's getting a bit fed up of finding 70 odd mail messages for me every
>Kelly wrote about my solar sail post:
>>The stellar radiation would be too breif and weak to help us much.
>I know it wouldn't be much good for a multimillion ton Asimov, but I had in
>mind a light interstellar shuttle to ferry personel and light supplies
>between the target star system and Earth, for which a solar sail might
>provide helpful additional breaking, especially at highish velocity, maybe
>passing the target star completely and reversing back, with the sail furled
>of course (and using gravity to help) - see my last mail. (By the way,
>Timothy, thanks for telling me that I can either count the photons OR
>calculate the Doppler shift. I knew that particle and wave mechanics have
>to be kept separate, so I'm not sure why I was being stupid. Always glad to
>have you to correct me!) This really links in to my ideas on the mission
>structure that I mailed to LIT just before I went off line (must be about a
>year ago now). I've dug it out and pasted it below. Is anyone still
>interested in mission structure? I don't recall we ever reached a complete
>agreement. Please let me know your reactions to this concept.
>Posted: 4 October 1995
>>I've got a few points to make about the general structure of the mission.
>>        Firstly, the mission should make future journeys to TC more
>feasable - this
>>would require the setting up of a small but expandable permanent presence
>>one of the terrestrial planets. The ultimate aim would be for the TC
>>to be effectively self-supporting. The mistakes of the Appollo program
>must be
>>avoided - it will be essential to maintain the momentum of the program,
>>the other alternative would probably be a general loss of intrest and a
>>back of manned interstellar travel.
>>       Secondly, I've always felt that using the Asimov to bring the crew
>home is an
>>inefficient solution. The Asimov is designed to be a heavy exploration
>>not a ferry. Once it has delivered its huge payload of machinery and
>>to TC, using it to transport a relatively few number of people back to
>Earth is
>>somewhat ridiculous.
>>       I would propose a fairly radical change to the mission plan.
>>        - The Asimov should be designed as a one way vehicle for
>exploration. Its
>>effectiveness in this role can be maximized if the return flight is no
>>an issue.
>>        - On arrival in the TC system it would serve as a permanent
>>command, control, and support centre for the develpment projects on the
>>Thus a permanent foothold can be established before planetary construction
>>even begun.
>>        - The construction of a 'colony' would be less frantic if those
>involved knew
>>that there already existed a safe haven for them in-system.
>>        - Two or more dedicated personnel transport vessels, designed
>separately from
>>the Asimov, should be constructed. They would only have to ferry people
>>small quantities of light supplies and equipment, and so would have a tiny
>>fraction of the mass of the Asimov. It might therefore be possible to
>>this type of vessel using solar sail and magsail technology, augmented by
>>artificial particle beam during the early phase of the flight, and a small
>>board antimatter engine for maneuvering and possibly as an early boost.
>>Ultimately, a two way particle beam between Earth and TC would be
>>It is even possible that the Asimov's engines might be used to produce a
>>to increase the acceleration of the small transport vessels back to Earth.
>>Cetainly it could provide many support functions for the transports (eg
>>communication relay, TC based mission control, repair).
>>        - These vessels would be used to relieve the crew of the Asimov
>with fresh
>>people. The round trip (time dilated) for the original crew might be 25-30
>>years (some might want to stay longer). With two vessels, a relief ship
>>arrive in TC every 15 years (TC time)
>>        If a permanent presence is to be established, it is clear that an
>>interstellar shuttle system is needed. Further, it is obvious that a
>>prohibitively expensive Asimov type vessel it not appropriate for this
>>function. I conclude that if an austere ferry system will have to be built
>>eventually, it makes sense to incorporate it into the original mission.
>>advantages of having the huge Asimov remaining as a planet-orbiting base
>in TC
>>are obvious.
>>Please respond with any opinions you might have about what I've said. Do
>>agree with my basic argument, if not the details?
>On another topic, I'm still not happy with the stellar drive system. It
>still seems to me (after reading everyone's mails on the subject) that for
>it to obey Newton's Third Law, it depends on a particular distribution of
>charge around the drive that may (or may not, for all I know, I haven't
>looked at this thoroughly) be statistically very probable, but surely isn't
>an absolute requirement. So I ask again: does this concept put conservation
>of momentum on an equal footing as the laws of thermodynamics (which are
>essentially statistical, not absolute)? If it does, either it's very wrong,
>or I'll be very, very, unhappy.
>Sorry I haven't responded as fully as I'd like to other people's mails, but
>I am reading them and  keeping fairly up to date.

Kelly Starks                    Phone: (219) 429-7066    Fax: (219) 429-6859
Sr. Systems Engineer                                     Mail Stop: 10-39
Hughes defense Communications
1010 Production Road, Fort Wayne, IN 46808-4106
Email:  kgstar@most.fw.hac.com