New Mars Forums

tahanson43206

Moderator

Registered: 2018-04-27

Posts: 19,365

Sunlight Natural at Various Locations in the Solar System

This topic is offered to assist NewMars members who are designing solar energy collection systems for various locations in the Solar System.

Per Google...

At Earth's average distance from the Sun (about 150 million kilometers), the average intensity of solar energy reaching the top of the atmosphere directly facing the Sun is about 1,360 watts per square meter, according to measurements made by the most recent NASA satellite missions.
Jan 14, 2009
===

In another topic, Void reported a finding that sunlight at Jupiter is (about) 3.7% of it's value at Earth.

This implies the solar energy per square meter is (about) .037 of 1,360 watts, or 50 watts per square meter.

A mirror designed to collect Solar photons to deliver 1,360 watts per square meter would need to be 27 times greater in collecting area, or 27 square meters, and that assumes 100% efficiency.

Per Google:

How much sunlight is reflected by a mirror?
Mirrors reflect between 85% and 99.9% of the light which is incident on them. Aluminium and silver mirrors reflect about 90 and 95 percent of incident respectively. These are the most common types of mirrors used in day to day life. 99.9% reflection is only found in perfect mirrors such as dielectric mirrors.

In a recent post, Void suggested an efficiency of 80%.

If 80% is the delivered efficiency at Jupiter, then the mirror would need to cover 33 square meters to deliver the equivalent of 1 square meter of sunlight at Earth, at LEO.

This topic is available for NewMars members to work out and post the specific sizes of mirrors needed to achieve specific objectives at various locations in the Solar System.

(th)

tahanson43206

Moderator

Registered: 2018-04-27

Posts: 19,365

Re: Sunlight Natural at Various Locations in the Solar System

This post is reserved for an index to posts that may be contributed by NewMars members over time.

(th)

GW Johnson

Member

From: McGregor, Texas USA

Registered: 2011-12-04

Posts: 5,796

Website

Re: Sunlight Natural at Various Locations in the Solar System

It's not hard to make a high-efficiency mirror:  it's front-silvered.  But that makes it quite vulnerable to damage.

Believe it or not,  ordinary household (back-silvered) mirrors are 97-98% reflective.

Those low energy density figures for sunlight in the outer solar system (beyond Mars),  are why nearly all spacecraft that went out there have been nuclear-powered.  You overcome that with a bunch of mirrors,  which to be practical over a long time-of-day,  must be steerable. That was not practical on a flying spacecraft,  but it might be for some surface-mounted installation.

GW

---

GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

tahanson43206

Moderator

Registered: 2018-04-27

Posts: 19,365

Re: Sunlight Natural at Various Locations in the Solar System

For GW Johnson re #2

Thank you for contributing to the launch of this new topic!

Your description of a large mirror system with steerable components is an opportunity for NewMars members to add posts showing mirror systems for various locations in the Solar System.

A free flying mirror system would be able to point at the Sun all the time.

The question then would be how to deliver the collected photons to where they would be useful.

In other topics, Void has been showing a variety of designs that might be considered for this application.

I'd like to encourage design of systems large enough to serve habitats.

(th)

tahanson43206

Moderator

Registered: 2018-04-27

Posts: 19,365

Re: Sunlight Natural at Various Locations in the Solar System

This post is to show an article from interestingengineering.com, about using reflectors to deliver natural sunlight to locations on the Moon.

https://interestingengineering.com/spac … 11.05.24_2

Solar reflectors to light up Moon’s permanently dark craters
Researchers are working to develop reflectors that redirect solar power to the moon’s craters.

Updated: May 11, 2024 05:17 AM EST
Prabhat Ranjan Mishra

Solar reflectors on Moon
Researchers at Texas A&M University have partnered with NASA Langley Research Center to engineer a solution using reflectors to get solar power to the bottom of lunar craters.

“If you perch a reflector on the rim of a crater, and you have a collector at the center of the crater that receives light from the sun, you are able to harness the solar energy,” said Dr. Darren Hartl, an associate professor of aerospace engineering at...

The reflectors in the Lunar application would (presumably) be steerable, to account for the Moon's motion in orbit around the Earth.

(th)

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,431

Re: Sunlight Natural at Various Locations in the Solar System

Wow, my connection dropped on p o s t transmission.

Now to attempt to remember what I wanted to say.

I would go with lots more smaller surfaces to reflect the energy to a common point to allow for a tighter transmission to be made so that it will not spread out as much as solar light does.

These can be inside of even earth's orbit and controlled to send that energy to Jupiter.

It comes down to how much energy to send for the given need.