Published: 2015-05-20 07:12:00
Updated: 2015-05-20 17:01:12
Posted May 20, 2015
By Tony Rice
An Atlas 5 rocket lifted off Wednesday morning from the Cape Canaveral Air Force Station in Florida.
The primary payload on this mission for the US Air Force is the X-37B Orbital Test Vehicle (OTV). This 29 -foot long, 9.5-foot high “mini-space-shuttle” began its life as a NASA project to create a reusable space plane before being transferred to the Department of Defense. Specifics of exactly what is aboard this and the other 3 OTVs is classified, but these reusable spacecraft do provide a platform for experiments which can be returned to, and examined, on Earth.
Like many Atlas 5 launches, a little payload space is available for small satellites carrying experiments aboard CubeSats. These miniaturized satellites are based around cubes measuring 10 cm on a side.
While small teams of students will eagerly watch each of the university led CubeSat projects, the crowd anticipating LightSail-A’s launch is much larger. 11,142 (and rising) private citizens have donated nearly $600,000 to fund the project.
LightSail uses solar pressure, or photons coming from the sun to provide low-thrust propulsion. The idea isn’t new, scientists like Johannes Kepler described effects of pressure coming from the sun and science fiction writers like Jules Verne have written about harnessing it for space travel.
The satellite uses an clever system for keeping itself steady in orbit. Three magnetorquer rods (oriented along the X, Y and Z axises) to interact with the Earth’s own magnetic field to provide attitude control (ACS). This enables the little spacecraft keep its sail pointed to the stream of photos so that it can “tack” like a sailboat in low Earth orbit.
Two hours after liftoff, LightSail will be ejected from the rocket’s upper stage and the ACS will engage beginning the process of aligning to the Earth’s magnetic field. An antenna will be deployed and begin transmitting about an hour later. Ground stations at California Polytechnic State University (Cal Poly) in San Luis Obispo and another at Georgia Tech will monitor the satellite as it orbits during the month long mission.
Should the launch occur on time, teams should get their first signals back from LightSail 19 minutes later when it is visible in the sky above Cal Poly. By 5:29 p.m. Eastern, teams at Georgia Tech will have their turn at tracking the satellite. In subsequent days images from onboard 2-megapixel cameras will be downloaded.
The teams plan to deploy the solar sails more than two weeks into the mission after a spacecraft checkout period. A small motor will be engaged and four tape-measure like booms will extend unfurling the solar sails. The mission is expected to live another two days at this point before reentering the Earth’s atmosphere.
Tony Rice is a volunteer in the NASA/JPL Solar System Ambassador program and software engineer at Cisco Systems. You can follow him on twitter @rtphokie.