
X-37b space plane’s microwave power beam experiment - clouddrover
https://www.thedrive.com/the-war-zone/33339/x-37b-space-planes-microwave-power-beam-experiment-is-a-way-bigger-deal-than-it-seems
======
DennisP
A couple years ago I read a book[1] on space solar power. It was written
before SpaceX really got going, and estimated a cost of 15 cents/kWh for a
gigawatt-size solar power satellite in GEO.

Old designs from the 1970s were monolithic beasts, and would be horribly
expensive even if launch were free. The new designs use a large number of
small identical components (of seven or eight types), which self-assemble in
orbit. That way you can mass-produce them.

I plugged SpaceX Starship launch costs into the book's estimate and got a
total system cost of 5 cents/kWh, which is pretty good for steady clean power
that doesn't need storage.

[1] _The Case for Space Solar Power_ by John Mankins

~~~
sandworm101
For space-based solar to be efficient, ie for it to be better than just
installing normal solar panels, the beamed energy would have to be at least as
powerful as sunlight (1000watts per square meter). That is a very very high
bar to overcome. Compared to the simplicity of solar+batteries, I don't see a
future for beaming solar energy down from space. Maybe once every square meter
of roof space has been dedicated to solar panels, once every city is
essentially blanketed in panels, then it may be time to turn to space for more
energy.

One might say that space-based solar would operate 24/7 and so is better than
normal solar panels. That's isn't reality. Low-orbit satellites spend half
their day in darkness too. To hit a receiver on the night side of earth a
satellite would have to be at a very high orbit, reducing beam efficiency and
increasing launch costs.

~~~
stcredzero
_For space-based solar to be efficient, ie for it to be better than just
installing normal solar panels, the beamed energy would have to be at least as
powerful as sunlight_

1) False. You just have to find contexts where installing solar panels is
undesirable or impractical. A forward military camp in the hills of
Afghanistan?

2) It's quite easy to exceed the energy density of solar panels with a
microwave rectenna to receive power. In fact, a lot of the old designs were
dedicated to _reducing_ the power density for safety reasons.

 _One might say that space-based solar would operate 24 /7 and so is better
than normal solar panels. That's isn't reality. Low-orbit satellites spend
half their day in darkness too._

Zero cloud cover. Zero dust buildup. In terms of access to solar flux, there
are a lot of advantages to being in orbit. Also, there's a "simple" way to get
around the tyranny of the rocket equation and get stuff to geosynchronous
orbit cheaply: mine the moon, manufacture the silicon solar panels there, and
use lunar electromagnetic mass drivers to deliver bulk cargo to geosynchronous
orbit. So I would agree with a lot of what you're saying about impracticality
with that caveat: "short of having lunar industrial infrastructure."

But, given a major power that has the above, how is this so different from
having fusion power?

EDIT: But if you carry forward this thinking a few steps, you get to...Oh NO!

So let's say that we don't get fusion power, but we do get to the point where
lunar industrial infrastructure looks within reach. In that case, control over
lunar resources will mean control over the most plentiful, clean, and
convenient form of energy. Basically, more than half of the motivation behind
major power wars in the last century and a half, has been control over
resources, particularly energy. Having energy resources gives one military
power which gives control over energy resources.

This dynamic would seem to set up the next major power conflict past the
Taiwan issue. Space could well wind up being the Caucasus Mountains/Persian
Gulf of the early to mid 21st century. A major power conflict over energy
resources which fundamentally involves the power densities implied by space
travel just seems like BAD NEWS.

Even worse. We first get the start of the above conflict. Then only afterwards
does rapid wartime R&D finally yields military grade fusion power. Yup, we're
living in our really nifty, really interesting Sci-fi future. "May you live in
interesting times."

~~~
henearkr
No nation could build this lunar mass driver alone. Maybe same thing for a
Dyson swarm. So, all those are international projects, if not completely
planetary projects. This reduces a lot risks of armed conflicts.

~~~
DennisP
According to the National Space Society:

> It is now believed that a lunar mass driver several kilometers long,
> designed conservatively with present technology, should be able to deliver
> 600,000 tons a year to L-5, or more easily to L-2, at a cost of about $1 per
> pound, assuming only ten years of operation.

[https://space.nss.org/l5-news-mass-driver-
update/](https://space.nss.org/l5-news-mass-driver-update/)

If SpaceX succeeds in dropping launch costs below $50/kg with Starship, this
doesn't seem like it'd be all that expensive.

~~~
henearkr
In this case, doing it internationally is just an option that I hope will be
taken...

By the way most huge companies are already international in some sense,
geographically or by employing many nationalities and origins. This also helps
avoiding conflicts.

------
MayeulC
What would it take to power an airliner?

Wireless power transmission would be ideal for a lot of applications,
transportation (electric cars, planes, maybe trains, UAVs, boats) chief among
them.

You could shave a lot of weight out of an electric plane by reducing its
battery capacity to an emergency supply. This would also greatly reduce the
carbon impact of flight transportation, while making a case for bootstraping a
beamed power constellation and ecosystem.

I guess that's something Nikola Tesla first envisioned :)

Unfortunately, from what I know, microwaves are not really harmless, unless
diffused over a large area, and you then need a large collector. An airliner
could do, if big enough. I don't know either if a beam can be steered fast
enough, and what would the economics behind be.

~~~
Someone
[http://large.stanford.edu/courses/2013/ph240/eller1/](http://large.stanford.edu/courses/2013/ph240/eller1/):
_“The power required to keep a Boeing 737-300 flying at a constant altitude
and speed is 7.2 × 10⁶ watts.”_

So, ballpark 7 MegaWatts, more during ascent, and add a bit if passengers want
to watch movies, eat hot meals, drink soft drinks, etc.

On the plus side, if the airplane doesn’t have to carry fuel, carrying
capacity could go up (with some redesign to make the plane strong enough to
land fully loaded), so that 737 might be equivalent to a 747.

That 737-300 has about 125m² of wing area, and, guessing, about the same are
for the body, so that would be 7MW/250m² = 28kW/m². The sun delivers about
1,400W/m², so that’s 20 times what the suns delivers on a cloudless day.

Now, most of the time, the ground station (or solar space array) beaming the
energy wouldn’t be directly below/above the plane, so the required power/m²
could go up a lot ⇒ I would make sure that any windows in the plane wouldn’t
let the microwaves through.

Doable? Possibly, but on ground level, I guess it would be wise to use a lot
more area for sending that amount of power up, to prevent killing birds.

~~~
MayeulC
Thanks for the figures. I'd guess that most of that power is used to combat
drag, which can be lowered by going slower. The rest is probably used to
combat gravity, especially during ascent, which should be improved by lowering
the amount of fuel.

A small battery, and/or a ground station at the airport could provide a bit of
extra power during ascent, and the battery recharged during flight. I guess
the extra power shouldn't amount to a lot more than 10kW...

Depending on the wavelength, it should be fairly easy to have the plane act as
a Faraday cage to shield its passengers. I guess the geometry could be
slightly tweaked as well to make a larger surface area, possibly using
trailing metallic wires to improve the energy collection area at a minimal
cost (I get that cylindrical wires are the worst aerodynamic shape, but it
should be less of a problem behind the wing).

If the wavelength is low enough, a coarse mesh could collect power quite
efficiently, but you'd have to worry a lot more about radio interference.

~~~
loeg
Drag and lift are related. Wings work by literally displacing lots of air
towards the ground.

If you go slower, you need bigger wings (also no one really wants longer,
slower flights in cramped airplane cabins).

~~~
krasin
Unless it's cargo. Cheaper than "normal air" / faster than sea shipping is a
reasonable niche.

~~~
loeg
I don't know if it's a big enough niche. There are quite a lot of costs to air
cargo aside from marginal fuel efficiency and somehow developing novel cargo-
specific aircraft has to translate into both increased profits for
Boeing/Airbus and decreased costs to shippers. Keeping in mind that these
slower craft would be unsuitable for some of the most profitable uses of air
freight today. I'm not sure it makes sense.

~~~
MayeulC
I guess that's part of the reason we still see propeller planes around (often
with the military).

Answering to a cousin comment, buses and trains can't compete when you need to
cross water :)

~~~
loeg
Well, there are boats. Passenger sailing as a means of travel is not
especially popular these days.

------
henearkr
THIS was the missing tech to start launching iteratively what will become a
Dyson's sphere.

The step zero could also be using Earth's deserts.

And then step one is using a space shell of satellites. Because the available
surface at a large distance of Earth is huge, even considering the constraints
of not creating too much shadow for life's photosynthesis.

Further in the future could be step two, some flotilla at Lagrange points or
even directly in a solar orbital between Earth and Mars (so that this will
never create any shadows to us).

~~~
fit2rule
I mean, this could happen: we deploy a microwave energy station above the
Sahara, and build that space tower ...

~~~
henearkr
In my idea, the energy production would be the solar-panel-satellites. Or the
deserts if we are only at step 0. But for drones and other energy-receiving
devices, imho the ground grid and batteries are still the best option, as the
wireless powerlinks towards the ground should be reserved to where it cannot
be avoided. Any smaller powerlinks from-space-towards-space would be fine
though.

~~~
fit2rule
solar panels in space -> microwave transmission to glass kiln -> glass towers
that reach up into the sky ..

~~~
henearkr
Wow nice, I didn't get your idea first, haha ^^

------
blackaspen
My first reaction to this was Sim City 2000's Microwave Power Plant (and the
occasional miss of the microwave beam):

[https://simcity.fandom.com/wiki/Microwave_(disaster)](https://simcity.fandom.com/wiki/Microwave_\(disaster\))

~~~
numtel
In SimCity 3000, the Microwave Power Plant is also first available in the year
2020. Coincidence? I think not :)

------
fabianmg
It sounds like a test for a future space weapon. Something that, anyone
correct me if I'm wrong, it's banned right now. They sell it as a new energy
source and that way they circumvent the ban.

~~~
avar
You are wrong. The Outer Space Treaty bans nuclear weapons in space, but e.g.
mass drivers shooting tungsten slugs which would have nuclear-like effects
aren't banned, nor is anything else.

Even if a treaty did ban these weapons it wouldn't be "illegal" for a major
power in any meaningful sense. These mutual arms restriction treaties are only
followed by the major power as long as they see a mutual interest in doing so.

~~~
jabiko
> These mutual arms restriction treaties are only followed by the major power
> as long as they see a mutual interest in doing so.

Sorry, but this really rubs me the wrong way. The whole reason we have these
kind of treaties is to protect nations which don't have the power to defend
their interests should a conflict arise.

Saying that it is normal for a nation to just ignore a treaty they have
ratified IMHO instills a very wrong mindset. If a nation ignores a treaty, the
reaction should not be "Oh, that was to be expected".

~~~
credit_guy
> If a nation ignores a treaty, the reaction should not be "Oh, that was to be
> expected".

A nation can withdraw from a treaty instead of ignoring it. The US just
withdrew from the INF treaty. In retaliation, Russia withdrew too (they were
the only signatories).

In 1936 Japan withdrew from the Washington Naval Treaty and built the
formidable battleship Yamato (armed with 18 inch guns, by far the largest in
WW2). What was the world supposed to do? The US imposed various sanctions on
Japan. At some point the sanctions became so hard that they amounted to an
economic death sentence. WW2 was not averted.

The unpleasant truth is that international treaties are not worth a whole lot.
For the simple reason that there's no international equivalent of law
enforcement.

~~~
jabiko
> A nation can withdraw from a treaty instead of ignoring it

Yes, as far as I can see both the INF and the Outer Space Treaty explicitly
include the possibility for a withdrawal (with prior notice).

At least this publicly signals the intent of a nation to do something which
would violate the treaty instead of just silently ignoring it.

------
ChrisMarshallNY
Wasn't Tesla consumed with beamed power? I seem to remember that was what
Wardenclyffe was about.

[https://en.wikipedia.org/wiki/Wardenclyffe_Tower](https://en.wikipedia.org/wiki/Wardenclyffe_Tower)

I remember reading a Repairman Jack novel about it. I think it was
Conspiracies.

~~~
h2odragon
AFAIK (which isnt far) he was always talking about using ground wave
transmission, too; which no one else had any idea how that was supposed to
work, then til now.

~~~
mhh__
> no one else

What makes you think he did?

------
choeger
The practicality rests on two open questions, I guess:

1\. How much power could a satellite generate, realistically? 2\. How many
targets could it serve simultaneously?

I imagine there is a huge difference between being able to support a single,
ultra lightweight drone and, say, hundreds of reapers.

~~~
m4rtink
1) Sun output minus conversion loses. Also you likely want nore than one, eq.
a Dyson Swarm.

~~~
4gotunameagain
"Sun output" at reasonable Earth orbits for this application is maximum ~1368
W/m2, and that only when the the panels are perpendicular to the direction of
the rays.

What is considered a "reasonable" orbit depends on our ability to collimate
the microwave beam's rays, which is not an easy task

------
dayofthedaleks
A global network of satellites beaming power to insect-sized drones near the
ground? Splendid.

~~~
teruakohatu
Remember simcity's microwave power station? Microwaves beamed down from space
:)

~~~
masnao
"it's all fun and games until somebody lose an eye"

in city telecom microwave antennas on top of buildings already kill thousands
of bird every day.

maintenance checklist start with "clean the dead birds from base of antenna"

~~~
dayofthedaleks
I don’t believe the frequencies used for terrestrial communications cause
injury, but rather birds are generally killed by physical impact with towers.
Much like windmills.

Please show a source if I’m mistaken.

~~~
sarbaz
The problem is that directly in front of a microwave antenna, power output is
on the KW order of magnitude. This is like standing in front of a microwave
oven with the door open - in a few seconds you will have severe burns.

------
stcredzero
Carrying one's power supply onboard a rocket in space and even on an airplane
is a huge weight penalty. What if high energy density beams could power a
substantial VASIMR thruster? That would make for awesome LEO to GEO orbital
tugs. It would also be a good basis for a drone "space fighter" that could
reduce the rocket equation penalty through ultra high ISP.

Reliable high density power beaming could enable fully automated cargo drone
aircraft. These would have fundamental advantages in operations costs due to
weight savings, the simplicity of electric motors, and reduced personnel
costs.

If we could generate large amounts of power in space and use sufficiently
large transmitters (re: diffraction limits) to beam it to VASIMR thruster
spacecraft, we could substantially reduce transit times to Mars, as one
example. Alternatively, we could also greatly increase mass fractions of cargo
delivery to Mars.

------
imglorp
24/7 availability was mentioned several times.

Does this mean it's possible to have a satellite in geostationary orbit that
is never eclipsed by the Earth? Or does it mean you have more than one
satellite serving a power receiver?

~~~
m4rtink
GEO satellites are pretty much always in the sun, minus couple hours per year
when they hit the (very snall at this altitude) Earth shadow.

~~~
4gotunameagain
GEO orbit is too high for this application, since it would require an insanely
collimated microwave beam (or insanely directional). The power loss is
proportional to r^2. Google "spherical spreading loss"

~~~
DennisP
That actually is doable. GEO is generally considered the best orbit for a
solar power sat. The receiver has to be several kilometers across, but that's
_good_ because you don't actually want to fry any birds flying through.

There have even been proposals to put transmitters on the Moon, but that's
stretching things.

~~~
4gotunameagain
Sure, but I thought the consideration here was about UAVs and the such :)

------
dirtyid
>In addition, it could allow satellites to provide reliable power anywhere on
the planet or even to spacecraft or other satellites in orbit.

Aka laser ASAT platform. Seems like one of those read between the lines Space
Force press releases. References to laser beam UAV kills, original research by
Revolutionary Munitions Directorate etc. All the remote power through
atmosphere interference sounds pretty fanciful TBH, whereas crippling
adversary satellites using beam energy instead of kinetic impactors (=space
debris) seems like the most parsimonious application.

~~~
SiempreViernes
It would be in line with the tradition of using "ballistic missile defence" as
a pretext for developing ASAT capability.

I would question if there really is such a strong push for even more US ASAT
tools in the USSF, though given the current administration I guess the "kill
'em all" mentality has a good wind in their sails.

~~~
dirtyid
My understanding is there's a much greater emphasis on counter-space
capabilities now that US military is shifting towards peer to peer
confrontations (China). ASAT... especially a concurrent global network is
going to be pretty key to nullifying the Chinese missile gap in SCS by
disrupting the killchain - Chinese satellites - in a manner that doesn't
endanger US space assets. Also this was a month ago:

[https://www.space.com/russia-anti-satellite-missile-
test-202...](https://www.space.com/russia-anti-satellite-missile-
test-2020.html)

Beyond just needing the capability, media releases like this seems to be
oblique posturing as well.

Edit: apparently posting to fast? Reply to below:

>ASAT warfare is hugely advantageous to them

Most threat models anticipate disrupting space assets in peer to peer
conflicts to mitigate technological edge. All the old ASAT tests have been
missiles that create debris (or potential debris in deliberate near misses),
Recipe for kessler syndrome if executed at scale. So moving to beam ASAT that
can disrupt / destroy sensors precisely without adversely risking the space
commons might not be a terrible development in terms of space arms race.

Also if memory serves some of the new Chinese satellite used to track SCS
shipping (US aircraft carriers) are in a high orbit that can't be hit by
current ASAT at all. So this might be developing new capabilities. It
certainly makes sense to hit other objects in space vacuum at speed of light
than to power drones through clouds.

~~~
SiempreViernes
> So moving to beam ASAT that can disrupt / destroy sensors precisely without
> adversely risking the space commons might not be a terrible development in
> terms of space arms race.

Um, lowering barriers for using weapons is obviously a bad thing: it means
they are more likely to be used, and cause a response by the adversary. So
unless you mean that this beam-tech should be freely shared all you're doing
is increasing the risk to the commons.

But my larger point is this: the incredibly costs of space weapons only make
sense if you think your adversary doesn't have any counter-move, this is what
I meant by my supposition that USSP thinks space warfare is advantageous.

To illustrate: remote detection can be counteracted by masking and decoys,
both of with are much more mundane than ASAT capabilities but will work pretty
good for a fraction of the cost and without any risk at all to the commons.

------
jarym
Anyone know what impact this will have on anything that gets in the way of
these high-energy microwaves? I’m thinking birds or manned aircraft?

~~~
fpoling
According to Wikipedia the power density of various proposal to beam energy
from space should be harmless for human.

[https://en.m.wikipedia.org/wiki/Space-
based_solar_power](https://en.m.wikipedia.org/wiki/Space-based_solar_power)

~~~
ben_w
At those intensities, microwaves seem significantly less useful than optical
PV.

~~~
m4rtink
Well, they work at night if your solar power satellite is high enough (eq.
GEO).

~~~
ben_w
The same applies if the beaming is done with an optical laser instead of a
microwave.

~~~
fpoling
Optical laser is rather inefficient at converting electricity into optical
energy. Surely there are some low-powered diodes where one can get over 50%,
but for powerful lasers efficiency like 1% is a good number. Consumer
microwave ovens on the other hand has efficiency like 65%.

------
passerby1
Can the effect of capturing and sending more enegry to Earth from space (than
Sun does now) be compared to global warming effects from currently burning
fossils?

~~~
andbberger
You can position the solar panels to shade the earth which wouldn't change the
total impinging power.

------
blendo
I was surprised to learn the rectenna was invented as recently as the 1960s:
[https://en.m.wikipedia.org/wiki/Rectenna](https://en.m.wikipedia.org/wiki/Rectenna)

And in 2015, the optical rectenna:
[https://www.me.gatech.edu/featured_colarectenna](https://www.me.gatech.edu/featured_colarectenna)

------
qwertox
If one assumes that the beam feeding the drone is not a cylinder, but more of
a cone with a Gaussian profile, then technology could get built which detects
the source and the target of the beam. So no matter how much you stealth the
drone, you'd have to deal with that new problem.

------
dghughes
The power must be enormous at the source. It would degrade considerably from
the source, inverse square law.

~~~
Turing_Machine
The inverse square law only applies to a point source radiating uniformly in
all directions.

Laser and microwave beams, while they do suffer from losses over distance,
aren't anywhere near that bad.

~~~
cevans01
The inverse square law still applies to directional transmitters and optical
transmitters. It's just that their transmit gain is much much higher.

------
JoeAltmaier
I wonder how they don't fall afoul of Tesla's patents?

[https://www.damninteresting.com/teslas-tower-of-
power/](https://www.damninteresting.com/teslas-tower-of-power/)

~~~
detritus
Possibly something to do with his having been dead for nearly 80 years?

~~~
JoeAltmaier
Somebody owns those patents...

~~~
Scarblac
Patents are only valid for 15 years or so.

~~~
willis936
That’s the idea. I have no clue what’s going on with big companies sitting on
stacks of tens of thousands of patents and litigating people for violating
patents unrelated to what the company produces.

------
willis936
Takeoff and ascension use the most power. What happens when it’s foggy and
cloudy? Do you have to wait it out? Planes cannot afford the weight of large
batteries.

------
Tade0
_“If we had a way to keep those drones and UAVs flying indefinitely, that
would have really far-reaching implications. With power beaming, we have a
path toward being able to do that.”_

Why go through all this trouble when there's this?

[https://www.amprius.com/amprius-silicon-nanowire-lithium-
ion...](https://www.amprius.com/amprius-silicon-nanowire-lithium-ion-
batteries-power-airbus-zephyr-s-haps-solar-aircraft/)

While 25 days is the record, I'm sure this thing can remain aloft for at least
a week at a time.

To me the solution from the article appears expensive and suspiciously
deathray-ish.

~~~
varjag
Because it's a superlight UAV without any instrument package or ordnance load.

~~~
Tade0
I see no indication that anything heavier could be powered via the method
described in the article.

~~~
varjag
The beam is on the order of kilowatts.

Noone is going to deploy satellite network just to power some semi-gliders.

~~~
Tade0
But how efficiently can the drones receive such a beam?

I checked and the Zephyr S has a 5kg payload - not much, but enough for
instrumentation. And they're making an even bigger one.

------
mrfusion
So what’s actually new here? Why can’t we test this same system on earth?

Is it a laser or a focused microwave beam? Will it hurt if a bird or airplane
flies through the beam?

~~~
tren-hard
They did test it on Earth, there's a bunch of examples in the article, but you
are limited to line of sight on Earth.

------
hawski
This would also have a great application for commercial flights. It would be
also a bit easier if energy would be sent only above clouds.

------
martinaoe2
anyone know what the conversion and transmission power loss is?

------
throwaway888abc
Seems great technology. Hope they also address any impact on ecosystem.

------
aaron695
Lol, we are going to spend billions to _possibly_ send down the power of a few
litres of fuel to a drone a day?

Maybe targeted at someones head it might pay for itself, but still pretty sci-
fi _if_ it was possible.

Just send from a blimp.

Or send the power up to the satellite to power them, it's good as free from
the ground, if this stuff is possible.

[edit] I would have ruled out this being a ruse to confuse people from the
military's side, since it's so crazy no one would believe solar panels in
space transmitting energy to earth was possible. But maybe not it seems..... I
assume IRL it's for communications, or jamming, shooting a missile out of the
air?

~~~
dr_dshiv
> Just send from a blimp.

Drone Mothership

