Laser Propulsion and Space
Based Solar Power
Keith Henson (L5 Society Founder)
Power down to Earth via lasers.
What does this have to do with
Transhumanism?
Running out . . . .
Carbon problems
The Basic Idea
Build one power satellite the hard way.
Equip it with propulsion lasers
Bring up material to build hundreds using the
first one.
Build more propulsion lasers as well.
Undercut/displace fossil fuels.
Three years ago
Three weeks ago
What changed?
Google China India Power Satellites
Last week in the news . . .
THE SABRE ENGINE
HEAT EXCHANGER
First SABRE Pre-cooler Module
This was manufactured in 2004
SABRE Pre-cooler Demonstration
Can’t be done with chemical fuel
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Current $20,000/kg to GEO
SpaceX $4,000/kg  $1,000/kg
20t/1400t, 1.4% payload
Skylon ~$1000/kg  $500/kg
7t/300t, 2.3% payload
Hydrogen combustion to 25 km, &
Mach 5.5 Laser heated hydrogen
above that point (laser beamed down
from GEO)
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2.3 to 3.4 GW of laser
Performance analysis, 54 t to LEO
Vehicle 24 t, (20% structure) plus
30 t second stage to LEO
2/3rd of second stage to GEO (20 t)
900 s, 6 deg sweep
over ~4000 km.
5845 m/s velocity
gain on 2.3 GW
GEO
320km
perigee
270 MW
laser source
after 5 hrs
760 s, 11 deg sweep
over 6950 km. 2500
m/s velocity gain
GEO
140 s,
1630 m/s
3670 km
320km
perigee
Hohmann
transfer
orbit 5 hr
$0
0
2
4
6
8
-$20,000
Millions of dollars
-$40,000
-$60,000
-$80,000
-$100,000
-$120,000
-$140,000
-$160,000
Years from start
10
12
14
Growth: 100GW/year, ten percent (10
GW) used for more propulsion,
triples the cargo capacity to 1.5 M t/y,
300 GW/year. Triple that and the
expansion rate is almost a TW/year.
It's possible that humanity could
be mostly off fossil fuels in two
decades. (Sandy is a factor.)
End of talk
http://hplusmagazine.com/2012/04/12/
transhumanism-and-the-humanexpansion-into-space-a-conflict-withphysics/
BUT—It is too big to do without
major government backing
• And oil, coal and gas industries will lobby
against a real solution. (Maybe not)
• So why should a government consider
backing it?
3.00
2.50
GW
2.00
1.50
1.00
0.50
0.00
0
2
4
6
Ve km/s
8
10
12
40. 00
35. 00
30. 00
25. 00
Payload
Percent
20. 00
15. 00
10. 00
5. 00
0. 00
0
2
4
Ex
6
Exhaust Velocity km/s
8
10
12
Payload cost as a function of exhaust velocity
Cost per kg
160.00
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0.00
0
2
4
6
Exhaust velocity km/s
8
10
12
Cost breakdown
•Vehicle amortization $10/kg
•Hydrogen $6/kg
•Laser $50 B (written off in 5 years)
•$10 B/0.5 B kg is $20/kg
•$36/kg, well under the $100/kg number
•Profit more than $50/kg
Completing 2.3 to 3.4 GW
•$ 34 B laser/power sat parts, 17,000 tons
•60 ¼ scale vehicles, 5 tons to GEO
•20 flights per day, 170 days, 2 years total
•Transport cost @ $100/kg $1.7 B
•Total cost $50-100 B
•Income @ $100/kg * 500,000 t $50 B/yr
•Payback from profit 3-4 years.
Chemical rocket (and planes)
can't build power sats but they
can build a large, expensive laser
• 3.4 GW electric power at 2 cent per kWh is
worth $480 M/yr
• 3.4 GW of laser propulsion is worth $50
B/yr
• >100 times as much
Part 4
This makes a business case
• It closes the business case for making 2 cent
per kWh power and we know there is plenty
of market at that price (TWs)
• It solves energy, energy security and carbon
problems (carbon neutral synthetic fuel for a
dollar a gallon)
• Even at two cents per kWh it makes huge
profits to support growth.
Simple analysis
• 10 year return on capital, 80,000 hours
• $1600/kW can be paid back at 2 cents per
kWh (Below coal to get market share)
• $200/kW rectenna, $900/kW parts and labor
($450 before transmission loss), $500/kW
for transport to GEO
• At 5 kg/kW requires
• $100/kg or less to GEO
It costs perhaps 10% of what a
war with Iran would cost
• SDI with the USSR or Russia was/is a
losing business.
• It will be decades before Iran could
overwhelm a multi GW propulsion laser and
by that time the commercial demand for
laser propulsion should be in the tens of
GW
• Cheap power from space removes any
legitimate reason to sort out uranium atoms
Google “henson oil drum” for a
slightly out of date “white paper”
on this topic
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Part 1 months ago
Part 2 and 3 a few weeks ago
Part 4 last week
This is unlikely to be the final evolution of
the idea.
Why Airdrop at 10 km
• Large Landing gear reduction
• Max landing is 54 tons, 120 t less 76 tons of
LH2 dumped in an abort.
OVERALL CONFIGURATION OF GEOSYNCHRONOUS
SPS (FROM DOE STUDIES)
SPACEBORNE
ARRAY
RECTENNA ON
EARTH
Percent payload (blue)
GW x 10 (orange)
Ve vs Payload % and GW (x10) for 6 km /s delta V
50 kg/s hydrogen feed, 20% structure
Percent payload (blue) GW x
10 (pink)
60
50
40
30
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0
2
4
6
8
10
12
Ve km /s
20
10
0
4
5
6
7
8
9
10
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Ve vs Payload % and MW/10 for 4.1 km /s delta V, 15,000 kg starting m ass
70.00
Percent payload (blue) MW /10 (pink)
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0
2
4
6
Ve km /s
8
10
12
Payload kg per MW and $/kg vs Ve for 4.1 km /s delta V
45.00
Payload kg per MW (blue) and $/kg (pink)
40.00
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
0
2
4
6
Ve km /s
8
10
12
40 kg, but just scaling from MW
to GW, move to Equator, cover
mountain with gyrotrons, run 4
minutes out of 20, 11 million
truck batteries, 5 years and they
die, but in that time 500 GW of
SBSP. Silly to send power down
and back up so . . . .
3.00
2.50
GW
2.00
1.50
1.00
0.50
0.00
0
2
4
6
Ve km /s
8
10
12
Percent payload (blue) GW x
10 (pink)
Ve vs Payload % and GW (x10) for 6 km/s delta V
50 kg/s hydrogen feed, 20% structure
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0
2
4
6
Ve km/s
8
10
12
Payload percent per GW and $/kg vs Ve for 6 km/s delta V
Payload percent per GW (blue) and $/kg
(pink)
180.00
160.00
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0.00
0
2
4
6
Ve km/s
8
10
12
105 kW CW
Getting started
(Building a seed laser)
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small scale, 500 MW @ 10 kg/kW
5000 tons, Falcon Heavy @ 20 t per flight
250 flights at 0.1 B/flight, $25 B
$5 B laser at $10/W
500 days at a launch every other day