It’s a good day for innovative space technology. The Planetary Society’s technology demonstration of solar sails to propel microsatellites hitched a ride into orbit with the launch of the secretive X-37B space plane. The LightSail project is testing solar sail technology for a mission in 2016.

Top image: Artist’s concept of the LightSail microsatellite. Credit: The Planetary Society/Mika McKinnon

Liftoff of the Atlas V rocket carrying the X-37B space plane and the LightSail CubeSat on May 20, 2015. Image credit: United Launch Alliance

The United Launch Alliance Atlas V rocket responsible for launching the X-37B space plane as its primary mission also carried 10 CubeSats into orbit as an auxiliary mission. The launch took place at 11:05 am EDT on Wednesday May 20, 2015 out of Cape Canaveral Launch Complex in Florida.

A totally nominal launch for the Atlas V rocket. Image credit: United Launch Alliance

Originally scheduled for May 6, 2015, the launch was pushed back until this Wednesday by the request of the Air Force who were troubleshooting problems with their space plane. The entire launch went as expected, blasting off at the start of the launch window and performing nominally while slipping the primary and auxiliary payloads into their respective target orbits. At least, we assume so — the launch had a blackout period of secrecy involving the X-37B where no information was reported.

Watch the launch highlights here:

Almost everything about the space plane has been kept secret, from which of the two spacecraft were sent into orbit to most of the on-board experiments. We do know about two experiments: characterizing the newest version of ion thrusters used by military communication satellites, and a NASA materials science experiment where small samples of 100 different materials will be directly exposed to space for 200 days.

In total contrast to the secretive space plane is the Planetary Society’s LightSail, one of ten CubeSats that made up the auxiliary payload. CubeSats are petite satellites measuring ten centimeters (four inches) to a side and weighing under 1.5 kilograms (3 pounds). The LightSail is composed of three CubeSats bundled together with four deployable Mylar solar sail covering a total of 32 square meters (344 square feet). The Planetary Society is making a concentrated effort at transparency including tracking information and instructions on how to spot the minuscule satellite when its sails are deployed.

Solar sail spread out during assembly. Image credit: Justin Foley

Solar sails function in a manner analogous to traditional sails in the wind here on Earth: the large, reflective material bounces photons, using that momentum to propel the spacecraft. By reflecting light off the mirrored sails, the craft receives a tiny boost of acceleration.While not much at any instant, the continuous thrust allows the spacecraft to build up large speeds over long periods of time.


For this test mission, the LightSail will be too low to properly solar sail, getting caught up in atmospheric drag. Instead, this is a shakedown-cruise, checking out how the satellite deploys its sail and other critical systems checks in preparation for an extended mission in 2016. The satellite will also be taking photographs. At this very initial stage, everything is looking good.

The Planetary Society is aiming to raise $1.2 million of the projected $5.45 million needed their LightSail project through crowd-funding. The ongoing campaign wants to take this beyond a proof-of-concept mission by paying for spacecraft construction, integration, and testing; orbital operations; data collection, analysis, and publication; and public outreach projects.

Alex Diaz and Riki Munakata test sail deployment on the LightSail spacecraft. Image credit: The Planetary Society

The other nine CubeSats deployed as part of the launch are the USS Langley, which will demonstrate the capacity to host a web server; Ballistically Reinforced Communication Satellite – Propulsion Test Unit (BRICSat-P), which will characterize the performance of tiny pulse plasma thrusters; ParkinsonSat (Psat), a communications satellite with a pair of transponders for the Amateur Satellite Service; Globalstar Evaluation And Risk Reduction Spacecraft (GEARRS), a demonstration of command and control technology in low orbit satellites; a pair of AeroCube-8s to demonstrate a carbon nanotube and scalable ion electrospray propulsion system; and a trio of Optical CubeSats acting as calibration targets for orbital debris studies.