tomcat,
I totally agree that bigger is better. Because you're absolutely right
about what's new and always getting improved about rocket engines and
of the fuel they burn, and even SBRs are getting into delivering more
reliable bang for their tonage. Per usable volume of interior, the CNT
spaceplanes of the future should outperform the existing shuttles by at
least 2:1.
Here's a bit more of what a Radon ION thruster might suggest. It's
actually getting a little embarrassingly super terrific as compared to
Xenon, but that may be entirely related to my math running amuck as
suggesting far more than what's actually obtainable. But even if I'm
only 0.1% right, it's still impressive. First look at the proven
Xenon/ion method;
Xenon - Atomic Mass: 131.29 Amu
Xenon ION thrust velocity @30 km/s
http://www.daviddarling.info/encyclopedia/X/XIPS.html
"These investigations showed that xenon offered the highest thrust of
any non-reactive gas; Ions ejected by XIPS travel in a stream at a
speed of 30 km/s (62,900 mph), nearly 10 times that of a conventional
chemical thruster."
Unlike the non-reactive(dead) aspects of Xenon, obviously Radon(Rn222)
might otherwise be considered as a highly reactive form of gas, as such
it seems entirely possible that the Radon ions should become nearly
photon ejected at half 'c', thus conceivably 150e3 km/s could be
suggesting a 5000:1 exit velocity improvement which should therefore
represent a rather impressive 5e6:1 improvement in the KE worth of
thrust potential and, Radon having the Amu of 222 is certainly much
denser than Xenon at the Amu of 131.3, so as to start with being worth
another 1.69:1
No matters what, besides Xenon having to be artificially obtained and
then highly insulated as a sequestered sub-frozen mass, of whatever
mass of Xenon is eventually going to run out, whereas a cash of
Radium(Ra226) that's creating Radon(Rn222) on the fly is good for a
half life of 1600 years.
Boeing 702: 25 centimeters in diameter = 165 mN of thrust
"Boeing Electron Dynamic Devices (702 Thruster), XIPS is 10 times more
efficient than conventional liquid fuel systems." The 702 offers an
individual range of power consumption up to 4.5 kW that obtains 3500
seconds/kg of Xenon ISP for creating 165 mN worth of thrust.
I'm certainly not the Radon(Rn222) ion thruster wizard but, I'm
thinking the amount of required energy as to ionize Rn222 that's
already somewhat on the go isn't going to be nearly as great as per the
none-reactive and thus passive Xenon. Therefore, the auxiliary power
source of electrons as being derived via PV cells, tether dipole or
that of an onboard reactor might be relatively slight on behalf of
energising ions from Radon.
If my reverse engineering is worth yet another bad example:
Xenon ION thrust at 165e-3/4.5e3 = 36.666e-6 N per J
Radon ION thrust 36.666e-6 * 5e6 * 1.69 = 309.8 N per J
Thus a MJ applied for creating a Radon ION thrust might be good for
309.8e6 N
The thrust per MJ in terms of Kgf becomes 309.8e6 * 0.101972 =
31.59375e6 Kgf
Obviously 36.6e6 Kgf of ION thrust per MJ seems a bit much. Therefore
perhaps the actual improvement in Ra222 ion exit velocity isn't going
to become worth the 5000:1 over Xenon ions, that is unless it somehow
turns into a laser cannon form of ion thruster, in which case the ion
velocity improvement could reach 10,000:1.
This radon/ion notion still represents having a rather sizable cash of
having to haul Radium(Ra226) about, perhaps several tonnes worth unless
there's some viable method of expediting the rate of decay into
becoming Rn222. Possibly forcing the decay of Ra226 within a reactor
might suggest upon one method of generating the onboard auxiliary
energy at the same time as per expediting the production of Rn222.
Otherwise having a continuously usable ISP of 3500 * 1600 years = 5.6e6
seems rather interesting. Not that the basis of any kg worth of Xenon
under continuous usage is going to be good for more than an hour,
therefore the actual Radium(Ra226)--Radon(Rn222) ISP half-life gets
way further past the mark of 5.6e6 * 8.736e3 = 48.9e9
Of course, as per the added mass of the external basalt composite
shield which need not come and go from earth, as equally for the cash
of Radium(Ra226) tonnage need not be onboard for the launch or reentry
phase. Having robotically pre-launched the Radium and whatever reactor
and/or Radon(Rn222) extractor into orbit is the same logic as to having
the basalt composite shielding pre-established in orbit, thus why the
spaceplane need not physically carry the added mass upon launch or
reentry. However, since there's no apparent shortage of Radon(Rn222) to
being had upon Earth, this is why a good amount of that element as a
frozen gas (possibly as a liquid or solid) could be utilized as a
portion of their launch thrusting energy via ion thrusters, although
I'd expect that in addition to whatever terrestrial heavy lift
aerodynamic transporter as was utilized in the SS1 case, a few SBRs
would remain the norm if the large spaceplane launch mass is
essentially representing several hundred tonnes in need of exiting
Earth's gravity at 8 km/s.
If the LSE-CM/ISS were established, as then parking the spaceplane
along side this 50e6 tonne CM(counter mass) as having the 1e6 m3 ISS
within is just the best ever spaceplane depot/pitstop you can imagine,
providing a good 50t/m2 worth of physical and radiation shielding that
should take whatever the sun has to offer without measurably impacting
the spaceplane crew and passenges that would simply vacate their
moderately shielded ride and wait it out within that relative safety of
the CM/ISS.
-
As per the usual, each and every day (as soon as my I get my PC
reconnected to this Usenet that sucks and blows, as such it's been
getting worse off than ever, as I seem to have attracted more than my
fair share of the almighty GOOGLE/NOVA V-Chip of automated seek and
destroy via spermware/malware as a gauntlet that's having been
specifically associated with my MI6/NSA Usenet interactions, thus
nearly always I'm having to frequently reboot because of their ongoing
efforts as to damage and/or eliminate my existence as far as my having
any public Usenet access or even so much as a working PC. This is still
the absolute ongoing truth and nothing but the truth that's easily 100%
provable, which seems only to further demonstrate that I'm essentially
right about most everything, thus apparently I'm worth targeting on
behalf of mainstream damage-control. The typical excuses that it's all
my fault, in that GOOGLE/NOVA and their partners of MI6/NSA in crimes
against humanity can't possibly avoid nor otherwise track a given
source of such spermware/malware, much less block it, is yet another
LLPOF proof-positive that I'm right about something that's apparently
not supposed to be public knowledge.
~
Kurt Vonnegut would have to agree; WAR is WAR, thus "in war there are
no rules" - In fact, war has been the very reason of having to deal
with the likes of others that haven't been playing by whatever rules,
such as GW Bush.
Life upon Venus, a township w/Bridge & ET/UFO Park-n-Ride Tarmac:
http://guthvenus.tripod.com/gv-town.htm
The Russian/China LSE-CM/ISS (Lunar Space Elevator)
http://guthvenus.tripod.com/lunar-space-elevator.htm
Venus ETs, plus the updated sub-topics; Brad Guth / GASA-IEIS
http://guthvenus.tripod.com/gv-topics.htm