Why Mercury?

Alternatives

Critics suggest Mars or the Moon as alternatives to Mercury. Let’s examine both options.

Mars: “Closer to Fly”

Resources: Mars is Richer

Element	Mercury	Mars
Iron (surface)	~2%	~17%
Water	Polar craters	Subsurface ice

At first glance, Mars wins. But resources aren’t everything.

Delivery: Mars is Cheaper!

Delivering an identical factory (62 t), then self-replication from local resources:

Location	Delta-v	$/kg	Delivery Cost
Mercury	8.5 km/s	$2,500	$155M
Mars	5.6 km/s	$1,600	$99M

Mass Driver: The Main Problem

Mars already has an atmosphere (0.6% of Earth’s) - it creates drag at 5 km/s. Mass Driver is impossible.

But more importantly - the project plans to terraform Mars:

One of the project’s goals is to create a dense atmosphere on Mars
After terraforming, the atmosphere will become even thicker
Mass Driver will become completely impossible forever

Alternative - rockets for each mirror:

Fuel from local resources: CO2 + H2O -> methane
Additional infrastructure
Each launch requires energy and resources

Swarm Orbit: Far from the Sun

The Swarm must be close to the Sun for maximum efficiency.

From Mercury: mirrors are already in the right orbit
From Mars: additional delta-v needed to transfer toward the Sun

Decommissioning: Where Does the Debris Go?

With a 10-year lifespan, ~110 million mirrors fail annually.

Mercury: mirrors fall into the Sun automatically
Mars: where to? Into Mars orbit - debris. To the Sun - additional energy required.

Summary for Mars

Factor	Mercury	Mars
Delivery of 1 factory	$155M	$99M (cheaper!)
Mass Driver	Yes	No (rockets needed, terraforming)
Swarm orbit	Already there	Transfer to Sun needed
Decommissioning	Yes - Sun	? Problem
Project timeline	~10 years	~12-15 years

Conclusion: Mars is cheaper for delivery but more expensive for operations - no Mass Driver, rockets needed for each mirror.

Moon: A Serious Alternative

Delivery: The Cheapest

Location	Delta-v	$/kg	Delivery Cost
Mercury	8.5 km/s	$2,500	$155M
Moon	5.5 km/s	$1,500	$93M

Resources: Aluminum

Element	Mercury	Moon (highlands)	Moon (mare)
Al	~7%	~14% (anorthosite)	~6% (basalt)
Si	~24.6%	~21%	~21%
Fe	1.5-2%	~5%	~14%

Aluminum on the Moon is sufficient. MRE (Molten Regolith Electrolysis) TRL 5-6 works with lunar regolith.

Mass Driver: Simpler Than Mercury

Parameter	Mercury	Moon	Moon’s Advantage
Velocity	4.3 km/s	2.4 km/s	1.8x lower
Acceleration	1275g	~640g	~2x lower
Energy per launch	3.6 GJ	0.35 GJ	10x less
Wear	High	Moderate	Longer service life

Lunar Mass Driver is simpler, more reliable, and more economical.

Energy: Mirrors Solve the Problem

Solar flux on the Moon is 7x lower. Is this a problem?

No. Swarm mirrors direct light to lunar factories:

Parameter	Value
Factory consumption	~124 MW
100 mirrors -> Moon	9,300 MW solar
At 18% efficiency	1,674 MW
Surplus	~13x

After launching the first ~100 mirrors, energy is no longer a constraint.

Communication and Iterations: Critical Advantage

Parameter	Moon	Mercury	Moon’s Advantage
Communication delay	1.3 sec	8-20 min	Real-time
Delivery time	3 days	3-4 months	Fast iterations
Cost of error	~$100-200M	~$500M-1B	5x cheaper

Error on the Moon: fix in a month. On Mercury: wait a quarter.

Receiving Infrastructure: Simpler

In the lunar scenario, the Swarm orbits the Moon/Earth, not Mercury. This radically changes the energy transmission geometry:

Scenario	Distance to receivers	Beam spreading	LSP area
Mercury	~100 million km	~1 km	5-10 km
Moon	~100-400 thousand km	~10 m	~100 m

Smaller beam spreading → compact receivers → cheaper infrastructure. Details: Energy Receiving Hub

Decommissioning: Requires Solution

Option	Delta-v	Feasibility
Drop to Moon surface	0.6 km/s	Possible
Leave in lunar orbit	0	Works (low density)
To Sun	3 km/s	Unrealistic

On Mercury, mirrors fall into the Sun automatically - decommissioning is free.

Political Risk

Moon: Outer Space Treaty 1967 - “province of all mankind.” Large-scale mining may cause disputes.
Mercury: No such attention, mining won’t cause protests.

Summary for Moon

Factor	Mercury	Moon
Delivery	$155M	$93M ✓
Mass Driver	Harder (1275g)	Simpler (~640g) ✓
Energy	Sufficient	Sufficient (mirrors) ✓
Communication	8-20 min	1.3 sec ✓
Iterations	Months	Days ✓
LSP receivers	5-10 km (spreading ~1 km)	~100 m ✓
Decommissioning	✓ Sun	Requires solution
Time to goal	~10 years ✓	~14 years
Politics	No issues	Possible disputes

The Moon is a serious alternative. Technically simpler, cheaper for iterations, but scales slower and requires solving decommissioning.

Tradeoff: Speed vs Risk

Strategy	Timeline	Risk	When to choose
Mercury	~10 years	High (errors $500M-1B)	Maximum speed, willing to risk
Moon	~14 years	Low (errors $100-200M)	Guaranteed result more important than speed

Optimal strategy: Moon as testbed + backup (years 4-6), Mercury for scaling (years 6+). If critical failure on Mercury, production transfers to Moon — project completes later but is guaranteed.

Overall Comparison

Parameter	Mercury	Mars	Moon
Solar flux	~9,300 W/m^2	590 W/m^2	1,361 W/m^2
Delta-v from Earth	8.5 km/s	5.6 km/s	5.5 km/s
Delivery of 1 factory	$155M	$99M	$93M
Mass Driver	✓ (1275g)	✗ (atmosphere)	✓ (~640g)
Energy for factories	✓	✓	✓ (mirrors)
Communication	8-20 min	4-24 min	1.3 sec
Debris disposal	✓ Sun	? Problem	Requires solution
Time to goal	~10 years	~15 years	~14 years

Conclusion:

Mercury — optimal for scaling (energy, disposal, speed)
Moon — optimal for testbed (communication, iterations, simpler MD)
Mars — not suitable (no MD after terraforming)

Why Mercury for Scaling?

1. Speed to Goal

Location	Time to 1.1 billion mirrors
Mercury	~10 years
Moon	~14 years

The 4-year difference means 4 more years of global warming.

2. Free Decommissioning

With 1.1 billion mirrors and a 10-year lifespan, ~110 million units fail annually.

Mercury: fall into the Sun automatically
Moon: requires solution (surface drop or special orbits)

3. Energy for Scaling

Solar flux 7x higher = faster factory self-replication. Critical in early stages (before ~100 mirrors).