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*To*: DotarSojat@aol.com*Subject*: Re: new web site/status report*From*: Kevin C Houston <hous0042@maroon.tc.umn.edu>*Date*: Wed, 10 Apr 1996 23:35:36 -0500 (CDT)*cc*: T.L.G.vanderLinden@student.utwente.nl, kgstar@most.fw.hac.com, stevev@efn.org, jim@bogie2.bio.purdue.edu, KellySt@aol.com, zkulpa@zmit1.ippt.gov.pl, rddesign@wolfenet.com, David@interworld.com, lparker@destin.gulfnet.com*In-Reply-To*: <960410163704_268651491@emout09.mail.aol.com>

Rex: >Kevin: > >(At 1G continuous thrust)...Even the antimatter rockets can't > >get up to .99 lightspeed with a mass ratio of 52. > > Two points-- > > 1. With the saturation of apparent velocity, the implications > of .99 lightspeed are obscured. A peak apparent velocity of I'm not sure I understand what you mean by this first sentence. > 0.99 ltyr/yr represents a peak proper velocity of 7.0179 > ltyr/yr and an acceleration distance (at 1g) of 5.90 ltyr. > (I.e., a destination distance of 11.8 ltyr with 1g deceleration, > also. BTW, my astronomy book gives the distance to tau Ceti as > 10.3+/-0.3 ltyr.) What mass ratio does MARS require to decel- > erate at 1g from this peak velocity? (I think that's the 52, > from Timothy's 3/30 table, that you're quoting, which is for > 100 percent conversion of captured microwave energy to exhaust > kinetic energy.) > > 2. An optimum antimatter rocket with a peak proper velocity Uend > of 7.0179 ltyr/yr has an optimum constant exhaust velocity Vexh > of 0.8851. The required mass ratio (r = exp[asinh(Uend)/Vexh]) > is 19.89. (These calculations assume no energy losses, but also > assume no gain from optimizing the exhaust-velocity profile.) > Okay, I stand corrected on the mass ratio point. but at least we can make microwaves :) (and don't tell me about the nine or so anti hydrogens that CERN got to live about 40 nanoseconds) I do think we should explore anti-matter rockets and see if they solve any of the really hard problems (like energy cost) Kevin

**References**:**Re: new web site/status report***From:*DotarSojat@aol.com

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