The Aristarchus is a solar sail spacecraft. Solar sails are a real
technology currently being investigated by NASA and other agencies as a way to
propel spacecraft in the future. This page presents a few facts about solar
sails, some links to solar sail projects, and how the Aristarchus fits
in with real projects under development.
- Solar sails are actually propelled by light. When light bounces off of a
reflective surface, some of its momentum is transferred and it can cause the
object to move.
- The Aristarchus' sails are coated in aluminum to
make them reflective.
- The reason light pressure doesn't move things on Earth is because it
provides a very gentle force. On Earth, gravity and air pressure are much
stronger than light pressure. But in space, where gravity
is weak and there is no air, light pressure can move objects.
- Sunlight only provides two pounds of force for every square kilometer. So
solar sails must be very large compared to the object they are propelling.
- Because the Aristarchus is a manned spacecraft, the sails must
be very large. They're over ten miles across.
- Present day solar sails are being built out of very thin material because
light pressure is so weak. The materials being investigated are between 40
and 100 times thinner than a piece of writing paper.
- The Aristarchus' sails are made out of a type of plastic called
quinitite. Quinitite hasn't been invented yet, but I imagine it to be very
strong and lightweight. Perhaps it's a matrix of polymer nanotubes. The
strength helps because of the sails' size and it helps deal with the real
modern day problem of rips in the sail fabric.
- NASA is in the process of developing solar sails. You can learn more
at NASA's NanoSailD Page. There's even a slideshow showing
the successful flight of NanoSailD.
- The Planetary Society is a non-profit group that is also building
a solar sail. Learn more at
the Planetary Society's Solar Sail Page
- The Aristarchus employs a similar design to the Planetary
Society's original Cosmos 1 craft. Both use sails that spin on masts attached
to a central hub.
- For more about solar sails, read the article "Sailing the Winds of Space"
by David Lee Summers serialized in three parts at his blog: