NASA's upcoming Technology Demonstration Missions are intended to "transform its space communications, deep space navigation and in-space propulsion capabilities." Three project proposals have been selected for these missions, which should be launching in 2015 and 2016. One of those projects, the Laser Communications Relay Demonstration, we've told you about already. Another, however, will be demonstrating a mission-capable solar sail. While NASA has recently tested a solar sail measuring 100 square feet (9.29 square meters), this one will be the largest ever flown, spanning a whopping 15,543 square feet, or 1,444 square meters.
So, what would one do with a solar sail that big?
For one thing, it could be used to gather orbital debris over a period of several years - sort of like a drift net fishing trawler in space. It could also be included in a satellite's payload, and activated at the end of the spacecraft's mission. The sail, still attached to the satellite, could then be used to drag it out of its orbit.
Not unlike a sea anchor, it could also be used to hold satellites in unstable locations. As an example, it could allow GeoStorm solar flare-tracking satellites to be located at points three times farther from the earth than is currently possible - the push of the Sun's rays against the sail would balance the pull of the solar gravitational field on the satellite, ultimately resulting in the spacecraft staying put.
Finally, it could be used as a propulsion system for deep space travel.
The Solar Sail demonstration mission will include demos of the sail's attitude control, passive stability and trim control, along with a navigation sequence executed "with mission-capable accuracy." The project is being led by California's L'Garde Inc., in collaboration with the National Oceanic and Atmospheric Administration and NASA.
The solar sail itself should be ready in three years.
All images courtesy NASA
I like solar sails, but its unfortunate that they\'re so damn slow...
I\'ve thought of the dragline technique to slow down a satellite. You\'d have to solve the static electricity problem before that became viable.
Note that drift nets and earthbound sails work at extremely low speeds compared to these orbital speeds.
IKAROS was 2,100 sq ft, which is far smaller. NASA\'s planned one is 15,546 sq ft, which is 7.4 times larger then Japans solar sail.
We proposed an orbiting clock composed of three separate structures to form the three hands, hour, minute and second. The defining limit was the rotational forces acting upon the second hand; at 3Km long, with a balancing tether, also 3Km long rotating every 60 seconds.
The hour hand at 6Km with a 6Km tether was the second largest; describing a diameter of 12Km and the minute hand was to have been 9Km long with, again, another balancing tether of 9Km giving a total diameter of 18Km. Each hand being a separate structure formed from mylar with carbon fibre reinforcing.
All three hands being held in shape by the centrifugal forces of their rotation about a central satellite with the rotation of each hand being driven from two separate solar powered motors at each tip.
The proposal was one of several entrants in The Eiffel Tower in Space, (Tour Eiffel de la Space), competition set in 1986 to celebrate the centenary of the design and construction of the original iconic Eiffel Tower in Paris. We were unofficially told that the judges were minded to give us the prize; but were told not to as they were not prepared to spend the $60 million to build and launch it.