This is very ambitious but a neat concept if it could happen.

In the video they use Skylon as a launch platform but with Spacex and Blue Origin coming online more maybe those present more options for such a project.

 

If your waiting on blue origin... You'll be waiting awhile.. Get that gallon cup of coffee.

Yeah a power satellite makes alot of sense. Microwave power beam to the surface.

 

Oh no not saying Blue Origin but there will be more options to launch stuff like this into LEO.

But then why not build all that on the Moon and beam power to Earth?

 

Expense. Costs a load to move supplies to Luna. Now if they can build it out of regolith, then might work.
A geo sync orbit would work.

 

Blue origin already is making rocket motors for ULA's Vulcan launcher, has it's own orbital launchers being readied, and is about to fly humans suborbitally this summer.

I suspect fusion power might undercut any attempt at space based solar power, but at the same time the moon does have helium3 and if it can be mined cheaper than being produced as a fusion byproduct, the moon is open for business.

O'neal had in mind space based solar power for powering the civilization in space he envisioned, but that technological event window may have come and gone. But cheap access to space will still find reasons for being up there, regardless.

When the world got a taste for bronze, Phoenician traders were going everywhere to hunt down ores to make it, travelling as far as Cornwall and probably starting the mining industry there. For them it might as well have been the end of the world but it was worth it.

And if someone could make thermal space solar competitive with some potential fusion power, (and that's a real concern) , there would be a real race going forward.

but there are a lot of if's involved in that.

 

BO engine? there years behind, while enough to cause ULA some headaches of if they have enough engines for future launches, and same engine is on new Glenn.. Which got pushed back. Space X is making an engine Per Day. Then went poor me to the GAO for the lunar lander. Beazos isn't doing to great. Probably because he teamed with all the legacy companies that are on the government teat. Shame really.

Well once Musk gets the starship working, 100 ton lift fully reusable, then we can start thinking big in space.

 

the more rockets the better I won't get tired of hearing of launches for a long time .

As I have moved to a new home and am unpacking, I just found my little Falcon 9 Launch Witness Certificate that LISATS was giving out at Jetty Park the day of the first Falcon 9 launch. Seems like forever ago now, and it really was the beginning of a new era. It's still exciting.

 

Yes, there's additional delta-V required. Additionally, only a few places near the lunar poles are in permanent sunlight and you'd have to erect rotating collector(s) just about perpendicular to the lunar surface in the Moon's gravity field (much weaker than the Earth's though that is). Elsewhere on the Moon, excepting permanently shadowed craters also near the poles, the lunar night is about two-weeks long. Fabrication of solar collectors from lunar regolith and transfer to GSO has long been mooted, of course. A geosynchronous orbit would experience daily eclipses of the Sun by the Earth of nearly 2 hours near the equinoxes. A Lagrange point such as L1, L4, or L5 might be more suitable but there'd a larger light transit time delay to take into consideration to prevent the microwave beam going off target.

 

Ah, forgot about lagrange points!
if you need 100% Sun, then the Earth-Sun L1 point would be ideal, granted its 1 million miles away, or 6 seconds or 12 second round time. But it is always in the sun. Or could do Earth-Sun L2-L3.

Just getting the power back, would a Microwave beam reach that far without degredation?

 

L4 and L5 have stable gravity wells; the other Lagrange points are metastable and require more active station keeping. A spacecraft at L2 would see an 84% annular occultation of the Sun by the Earth - the Sun and Earth subtending solid angles of 16.674 μsr (microsteradians) and 14.011 μsr respectively. Spacecraft at L2 such as Gaia follow a Lissajous or halo orbit around L2 to ensure their solar panels receive enough sunlight. L3 is the opposite side of the Sun so it would be about 1000 light seconds distant and the Sun is obviously in the way.

 

I expect it would, but given the sheer quantity of solar energy that is wasted in space every day, every hour, it's reasonable that even if some of it was lost in transit, it would still be worth gathering.

 

Coherent maser beams will exhibit diffraction like all EM radiation with a central peak angular spread given by approximately 2.arcsin(λ/d), where λ is the wavelength and d is the diameter of the transmitting antenna's dish. If λ << d, this is approximately 2λ/d radians - obviously we need to keep λ small relative to d in any case. The radio window of the Earth's atmosphere is between the frequencies of 5 MHz (60 m) and 30 GHz (1 cm) so λ needs to be in this range. Let's assume λ = 0.03 m (3 cm corresponding to 10 GHz) and a transmitter dish diameter of 10 m. The width of the central beam at a distance D between transmitter and receiver would be approximately 2Dλ/d. For D = 36,000 km (geostationary orbit) that gives a beam width at the receiving station of 216 km. That seems far too large to be practical to me. The problem is only going to be made worse by stationing the transmitter at a Lagrange point. If the power satellite is orbiting at 360 km, the beam is 2.16 km across at its narrowest intersection with the Earth but you then have the problem of building multiple power satellites and/or multiple receiving stations as well as coordinating these. It's a long time since I read about this stuff so I stand to be corrected. I assume such considerations - besides the high cost of hefting mass into orbit - may be why we stuck with Earth-based solar power.

 

L1 is not a bad place to put a sunshade, however.

 

Stationkeeping against solar photon and solar wind pressure would be an issue for a large occulting structure at L1 though. It'd be an interesting "Fermi problem"* to set a Physics undergraduate.

* Other examples are estimate how many piano tuners work in Chicago or how many carbon atoms in your body were once part of Julius Caesar.

 

https://space.nss.org/making-sun-shades-from-moondust/

 

Interesting article but each swarm member would also need active propulsion to counteract solar photon and solar wind pressure. Ion thrusters would probably do but the propellant would need to be topped up every now and again. A constellation of shade satellites in geosynchronous orbit would probably be a more feasible way of controlling insolation. These satellites could also be constructed on the Moon in robotic factories. Astronomers would be no doubt be annoyed to have such objects in orbit.

 

With the amount of off-world infrastructure that would create they'd have so many space telescopes (and moon based observatories) they'd have enough data to sift through for lifetimes.

 

A Sun-synchronous orbit (SSO) might be better for shade satellites. I'm not sure what orbits and arrangements are optimal. If they could also harvest solar energy so much the better.

Sun-synchronous orbit - Wikipedia

 

"Open any newspaper and you will likely see some mention of global warming—usually on the front page."

This person is reading better newspapers than I've seen around...

 

I haven't read a physical newspaper in some time. I should try it.