You didn't understand the argument. With terrestrial solar panels, you capture as useful energy some energy which *would otherwise end up absorbed by Earth anyway*. With SBSP, the energy you capture and send to Earth *would otherwise fly past the planet*.
Quote from: gospacex on 07/01/2014 10:16 amYou didn't understand the argument. With terrestrial solar panels, you capture as useful energy some energy which *would otherwise end up absorbed by Earth anyway*. With SBSP, the energy you capture and send to Earth *would otherwise fly past the planet*.It does not matter whether you include terrestrial PV albedo (making light reflective sandy deserts much darker) or not:It is still insignificant compared with total solar influx and GHG heat trapping.
I didn't say it matters. I said that your argument "but terrestrial solar PV also dissipates waste heat" is wrong, because that solar energy would arrive and be dissipated in this location *anyway*.
Quote from: gospacex on 07/01/2014 10:45 amI didn't say it matters. I said that your argument "but terrestrial solar PV also dissipates waste heat" is wrong, because that solar energy would arrive and be dissipated in this location *anyway*.I'm glad we agree it doesn't matter.
Quote from: SICA Design on 07/01/2014 10:51 amQuote from: gospacex on 07/01/2014 10:45 amI didn't say it matters. I said that your argument "but terrestrial solar PV also dissipates waste heat" is wrong, because that solar energy would arrive and be dissipated in this location *anyway*.I'm glad we agree it doesn't matter.It may not matter for one satelite.How many satelites can you build befor it starts to matter?50 GW?500 GW?5 TW?
Btw, tracking modules which combine concentrated thermal electric and pv can get 60 - 80% efficient.
...why not send up an inflatable array...
Quote from: Asteroza on 07/01/2014 09:16 amMaybe I'm not understanding correctly, but what happens when the SPS lines up with the day/night terminator line while near the top of the Molniya loiter then, unless you phase orbits to avoid that scenario?HESPeruS is never in Earth's shadow when other beam constraints are met. A Molniya orbit is inclined at 63.4deg taking it WAY above the northern hemisphere. The diagram is not to scale (obviously), but the solar angle (shown from Earth's tilted perspective) and orbit proportions are correct. The "SPS" represents a small section of one module - the tiered arrangement is at ~25mm scale.Were you considering something similar to 70 minute GEO outtages during Spring/Vernal equinoxes?
Maybe I'm not understanding correctly, but what happens when the SPS lines up with the day/night terminator line while near the top of the Molniya loiter then, unless you phase orbits to avoid that scenario?
Though that makes for interesting orientation issues, likely compensated by smart precession and beam steering.
How does HESPeruS keep modules on opposite sides of the array in phase for beam forming?
I have discussed the possibility of boot-strapping construction (using one SPS to boost the components for another into Molniya via microwave thermal propulsion) with Keith Henson. However, he suggests the orbital phasing and beam times will not work in its favour.
Quote from: SICA Design on 07/02/2014 08:18 amI have discussed the possibility of boot-strapping construction (using one SPS to boost the components for another into Molniya via microwave thermal propulsion) with Keith Henson. However, he suggests the orbital phasing and beam times will not work in its favour.That's a little unexpected, but possible. Skylon dumping direct to a Molniya inclination but a sub-450 km circular parking orbit seemed to be a good choice at first. After that trade against full construction then apogee raising of a completed SPS or apogee raise all parts module by module before joining. Single module apogee raising using something like a microwave powered Flyut while the bootstrap SPS sweeps towards perigee seems doable even if microwave Skylon itself is unattractive due to launch site distance from perigee ground track specific to the Molniya orbit you wish to service.
[Edit2]...and the missiles agree to play fair and send out a 40.68MHz homing signal
Quote from: Asteroza on 07/02/2014 11:36 pmQuote from: SICA Design on 07/02/2014 08:18 amI have discussed the possibility of boot-strapping construction (using one SPS to boost the components for another into Molniya via microwave thermal propulsion) with Keith Henson. However, he suggests the orbital phasing and beam times will not work in its favour.That's a little unexpected, but possible. Skylon dumping direct to a Molniya inclination but a sub-450 km circular parking orbit seemed to be a good choice at first. After that trade against full construction then apogee raising of a completed SPS or apogee raise all parts module by module before joining. Single module apogee raising using something like a microwave powered Flyut while the bootstrap SPS sweeps towards perigee seems doable even if microwave Skylon itself is unattractive due to launch site distance from perigee ground track specific to the Molniya orbit you wish to service.I haven't tried to model this; Keith has for laser-thermal GTO, but I'd presume not for Molniya. Would anyone here like to have a go? The diffraction limit at 5.8GHz, from a 4.4km diameter antenna down to a 1 metre spot, gives <35km beam distance, which is one reason for pessimism.[Edit]Could make a good anti-missile defence for the SPS though; provided the missiles abide by the rules and don't try to attack the non-beaming side! [Edit2]...and the missiles agree to play fair and send out a 40.68MHz homing signal
Should use lasers and find a customer that needs a lot of power and is willing to pay a LOT more than $0.10/kWh and lives above the clouds and could use a system at the hundreds of kW range to start.