[AR] Re: NASA test of quantum vacuum plasma thruster (was "Anyone heard of this?")
- From: Keith Henson <hkeithhenson@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Wed, 6 Aug 2014 07:04:21 -0700
On Wed, Aug 6, 2014 at 3:05 AM, Peter Fairbrother <zenadsl6186@xxxxxxxxx> wrote:
> On 06/08/14 01:13, Keith Henson wrote:
>>
>> On Tue, Aug 5, 2014 at 3:00 PM, Peter Fairbrother <zenadsl6186@xxxxxxxxx>
>> wrote:
snip
>>> It would only come into its own where final velocities above about 50
>>> km/s
>>> are needed, and even a Vasimr drive would need a mass ratio well above
>>> 10.
>>
>> Wait, VASIMR engines reach 50 km/s exhaust velocity. 1-1/e is about
>> 63% reaction mass.
>
> Ah, I was using your 20km/s (typical VASIMR) figure.
VASIMR is Variable Specific Impulse Magnetoplasma Rocket. If you have
power and time you can crank up the ISP. I should work out the lowest
cost ISP for the LEO to GEO run. I did this some time ago for laser
heated hydrogen and found that about 7.5 km/s worked well. Less that
that got expensive fast because the payload went down, but higher
exhaust velocity didn't buy you much because the power required went
up as the square of the exhaust velocity.
Even using them 95% of the time, big lasers have a high cost.
Microwave generators are much less expensive, but microwave optics
forces the LEO to GEO transfer vehicles into a size of 15,000 tons
payload.
The artwork on shows a Skylon cargo container being added to a second
stage. The second slide shows the cargo under way using VASIMR
engines making the purple glow. The engines are powered by microwave
from the ground per Bill Brown's 1992 paper.
https://drive.google.com/file/d/0B5iotdmmTJQsamt1Tk1BaXlwaXBqLUhubS10VTJ4MnItSFNr/edit?usp=sharing
https://drive.google.com/file/d/0B5iotdmmTJQsNVZxWWxRN0oyWXMzRlB0d0F4aFJOazRiZG9n/edit?usp=sharing
https://drive.google.com/file/d/0B5iotdmmTJQsUkNUak9hYmFoU3B5UFpmUVVYSEJ1VGF1cHVB/edit?usp=sharing
https://drive.google.com/file/d/0B5iotdmmTJQsYnVway1JRGRJVzVEUXloTXBwdDVLRllUNUZJ/edit?usp=sharing
Ground transmitter size, 10 x 14.1 km.
https://drive.google.com/file/d/0B5iotdmmTJQsZlhneC1BLTNicU42OWI5MHhpSEJXZWFOQjE0/edit?usp=sharing
The object is to lower the cost of energy to less than half the cost
of energy from fossil fuel.
Sorry for the topic drift
Keith
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