Sunjammer (spacecraft)

Sunjammer (Solar Sail Demonstrator) was a NASA mission intended to demonstrate a solar sail constructed by LGarde, but was cancelled before launch. The largest solar sail made as of 2013, Sunjammer was named after a 1964^[1] Arthur C. Clarke story of the same name, Sunjammer, in which several solar sails compete in a race across the Solar System.^[2] Sunjammer was slated to launch in January 2015 as the secondary payload of a SpaceX Falcon 9 rocket, along with the Earth observation satellite DSCOVR.^[2] Citing a lack of confidence in its contractor’s ability to deliver, the mission was cancelled in October 2014.^[3]

Spacecraft design

Constructed of Kapton in order to withstand the extreme temperatures of space, Sunjammer has a width and height of 38 metres (124 ft), giving it a total surface area of over 1,200 square metres (13,000 sq ft) and making it the largest solar sail as of 2013.^[4] Despite its huge surface area, Sunjammer has a thickness of only 5 μm, giving it an extremely low weight of about 32 kilograms (70 lb) and allowing it to be stored in a space the size of a dishwasher.^[4] Once in space, the large surface area of the solar sail would allow it to achieve a thrust of about 0.01 N—roughly the weight of a sugar packet.^[5] To control its orientation, and via this its speed and direction, Sunjammer was to use gimballed vanes (each of which is itself a small solar sail) located at the tips of each of its 4 booms, instead of thrusters, completely eliminating the need for any propellant other than the rays of the Sun.^[5]

In addition to being a demonstration craft, Sunjammer was to collect scientific data in its own right. With several instruments to detect various aspects of space weather, Sunjammer could have eventually become part of a larger network of solar sails studying the Sun, allowing for the creation of a more robust early-warning system for space weather.^[2]

Mission

Prior to its cancellation, Sunjammer was slated for launch in January 2015 aboard a Falcon 9 rocket, a slight delay from an earlier projection of November 2014. It was to launch as a secondary payload along with the primary DSCOVR Earth observation and space weather satellite.^[2] Within two months of launch the spacecraft was to test various technologies, such as deployment, vector control via altitude vanes, and eventually reaching a location near the Earth-Sun L₁ Lagrangian point.^[4]

Payloads

Sunjammer was to carry two British space science payloads: the Solar Wind Analyser (SWAN) developed by the Mullard Space Science Laboratory of University College London,^[6] and the MAGIC magnetometer developed by the Blackett Laboratory of Imperial College London.^[7][8]

Sunjammer was to carry a Celestis Memorial Spaceflight payload of cremated remains.^[9]

References

External links

• Sunjammer Solar Sail Mission Sunjammermission.com web site
• Sunjammer L'Garde Inc. Sunjammer page
• Solar Sail Demonstration (The Sunjammer Project) NASA Sunjammer Mission page
• The Sunjammer Solar Sail: Making Your Loved One Part of Space History Celestis Sunjammer page
• Sunjammer Space and Atmospheric Physics Group, Imperial College London