Postcards To Space is developing the Spin Tumble Rotate Evaluation (STREET) space sculpture. STREET is a 325' diameter ring of inflatable plastic film and an avionics package. Fully deployed, STREET will be the size of two football fields. The first version is planned to fly in 2008. Postcards received before January 31, 2008 will be printed on this craft.

Explanatory Graphics
STREET space ring | Postcard Display

... You ordered the Postcard but never thought it would work. Filled it out and sent it in. Two and a half years later you receive an email with your chicken scratched note to the Cosmos with the crescent Earth behind it.

... After a long night of dancing, you and your friends are skipping in the waves of Coney Island before dawn. The Postcard Locator on your cell phone beeps, tells you just where to look toward the purple southeast and everyone starts shouting "Look, look, there it is!" Streaking past is the STREET ring glittering above the dawn.

... Your inbox has a new picture, your Daisy superimposed over a red planet with the giant discus of the Sail in the corner. Clouds drift below as the video clip plays, flashes of hundreds of Postcards streaming past as the camera pod spring-launches from the Sail's axle, your perspective widening as the axle, cvurve of the sail and the limb of Mars pull into view.

Postcards To Space, the Project: San Bao design group and the STREET space ring are following an evolutionary path toward first flight. The project only advances with consumer confidence, that is, individuals support the P2S effort by purchasing Postcard kits, filling them out and returning them.

Following a series of media-driven demonstrator projects, Postcards To Space will launch the packaged STREET (Spin Tumble Rotate Evaluation) spacecraft into Low Earth Orbit (LEO) on a commercial US rocket. Once ejected from the carrier rocket, STREET activates a line cutter to deploy the main ring. The ring is stored as a series of accordion-folded tubes inside a protective cube of solar panels. The ring inflates automatically, using heptane or a proprietary technology. When freed from compression the material boils in the tubes. At deployment, the protective solar panels expand around the main axis, providing a shock structure and holding tethers and power equipment away from sensitive electronics. The tethers spin out from the bus as the 100 meter silver ring inflates around it. At full inflation the ring is equivalent to 3 football fields in area, resembling a giant bicycle wheel.

The general configuration for STREET is a torus (doughnut) of plastic foil rigged with tethers to a central axis that includes avionics and power bus. This bicycle-wheel configuration has stability and scalability advantages over some proposed gossamer craft and neatly solves the high-power loopback needed to make electrodynamic propulsion practical. A circle with spokes is naturally tensioned. Cross-sections for the ring include tube & inner tube, single wall tube and double-tubes with a flap between, resembling a bar-bell. Further versions of the craft will range up to kilometer scale, STREET is a technology demonstrator as much as space sculpture. The spacecraft is a conceptual descendant of Echo I and the recent Cosmos I solar-sail attempt.

The ring will be visible from the ground with a sunlit brightness of at least -8 magnitude, depending on time of day and viewing angle. STREET will appear as a diffuse-to-brilliant circular object sweeping overhead. Average surface area of the craft is 2200m^2, mass is between 40 and 400kg, plus additional electronics. The spacecraft hardware includes the Postcard Display, cameras, packet radio and gyroscopic reaction wheels. Software will include encrypted, IP-addressable components and tight links with experience-enhancing Internet services.

Partner logos will be visible on other cameras, on the hardware or the inner arc of the ring.

Part of the ring is self-hardening and creates a stable structure for the craft. As required the entire structure can spin-up along the Z axis, the reaction wheels also provide general 6DOF pointing. The craft does not have a propulsion system or RCS thrusters, instead it uses light pressure, spin and possibly electrodynamics for all positioning.

As STREET orbits, it will display all the Postcards that made the mission possible. The Postcard Display is an electronic display coupled to a high definition video camera. After satisfying this major requirement, the Postcard Display will be opened up to uploadable email and TXT messages. A "send the cosmos to someone" messaging option will allow users to forward messages through STREET and on to friends.

STREET flies in LEO for several weeks to months, atmospheric drag guarantees the craft will deorbit quickly unless boosted to a higher orbit. Candidate orbits have a high enough inclination to be visible from major population centers. Orbits other than LEO present an interesting trade-off between visibility and craft duration. No material survives reentry.

Goals include advancing the use of inflatable space structures with this unique project, encouraging commercial space development and creating personal connections with the larger universe.

Future products will be developed alongside producing a series of ring scupltures. The STREET ring, derivatives and associated development is technically and aesthetically achievable. The technology and practices developed can lead to applications such as solar sails, long-lead cargo delivery ("space tug"), photovoltaic/solar-dynamic reflectors, deployed shapes, telescope components and spacecraft tankage technology. The creative aspect of the project enables a true personal connection with the space experience, creating more support for all space projects.

The state of the art allows delivery of huge gossamer structures, they have been repeatedly flight-proven. That capability can now be used to inspire.

You can support this effort: Purchase Postcards Here