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Re: New idea Laser launcher/scoop systems
- To: KellySt@aol.com, kgstar@most.magec.com, stevev@efn.org, jim@bogie2.bio.purdue.edu, zkulpa@zmit1.ippt.gov.pl, hous0042@maroon.tc.umn.edu, rddesign@wolfenet.com, David@InterWorld.com, lparker@destin.gulfnet.com, bmansur@oc.edu
- Subject: Re: New idea Laser launcher/scoop systems
- From: T.L.G.vanderLinden@student.utwente.nl (Timothy van der Linden)
- Date: Fri, 08 Mar 1996 16:32:22 +0100
Reply to Kelly and Steve, worring about ratios
>Actually, now that I think about it there is a dangerous likely flaw in
>this fuel launcher idea.
>
>Remember a while back when I ran the numbers on fuel-to-payload ratios
>for different fuel types? Remember that hydrogen came out at _minimum_
>to need 1,000,000 units of hydrogen to one unit of payload to reach even
>low relativistic speeds.
It's a long time ago already, so I dug up you formula:
/ 2 \ ArcTanh[v]/a
| r Sqrt[1 - a ] |
f = | ---------------- |
\ r + a /
f = fraction of mass that can be payload
r = reaction mass velocity (in lightspeed)
v = final spacecraft velocity (in lightspeed)
a = acceleration (in lightspeed --> 10 becomes 10/c)
Using a small r (0.081c) gives ratios of about f=1/45 which seems reasonable
compared to your 1:1,000,000. All this is for v=0.3c
For v=0.2 this ratio is down to 1:12, and for v=0.4 it is 1:180
With my own formulas I come to the same conclusion, some time ago I tried to
convince Kelly that with a 1:16 ratio we could come quite far.
Tim