Weighing in at less than three kilograms and measuring thirty centimeters by ten centimeters square, the Radio Aurora EXplorer (RAX) is the first National Science Foundation sponsored satellite mission.
RAX was built in response to a growing demand for smaller, more affordable satellites able to perform science missions. It is based on the cube satellite, or “CubeSat” concept, a standardized platform that enables launch vehicles to provide affordable access to space when there is room on their rockets for small spacecraft.
The RAX-1 CubeSat being integrated into Cal Poly's P-POD, the mechanism that secures RAX to the launch vehicle and deploys the satellite once orbital altitude is reached.
The CubeSat trend began at Stanford University and CalPoly San Luis Obispo in the early 2000s. One of the most compelling qualities of a CubeSat is its ability to optimize space and weight. CubeSats can easily replace traditional ballast on rockets, thus allowing students access to space in an unprecedented manner.
As of April 2012, 62 CubeSats have been launched since the concept was conceived, demonstrating the potential to influence a whole-scale reduction on the cost of access to space for smaller space missions. Tremendous effort has been put into ensuring that these CubeSats can de-orbit properly, in order to avoid creating space debris.
RAX-1 and RAX-2
There are currently two RAX satellites in the RAX mission. The first satellite, RAX-1, was launched in November 2010 and successfully performed scientific experiments while demonstrating the functionality of the satellite subsystems on-orbit.
The RAX-1 Satellite. Photo credit: Tanner Beck
RAX-1 was a demonstration of the mission’s technological capabilities – it made great strides in CubeSat design, and was able to execute bistatic radar measurements that had never before been performed on a satellite of its size. Unfortunately, the mission ended prematurely after approximately two months of operation due to a gradual degradation of the solar panels that ultimately resulted in a loss of power.
The RAX-1 mission patch, designed by Allison B. Craddock and the University of Michigan Team.
RAX-2 builds on this heritage to continue the scientific mission mission; it is a reflection of students learning from experience, and implementing new, more inventive technologies firsthand. RAX-2 was developed to correct the power failure and enable scientific experiments at regular intervals.
The RAX-2 satellite. Photo credit: RAX team.
In early 2011, the team performed thorough ground-based testing to investigate the cause of the solar panel degradation, and concluded that it was caused by shadowing of the solar panels by the turnstile antenna extending from the top of the satellite. Partial shadowing of the panels can result in a reverse bias voltage that destroys the solar cells.
The RAX-2 mission patch, as designed by Vicki Moore and the SRI International Team
The panels were redesigned for RAX-2, which was built in Summer 2011 using many parts from a spare RAX-1 flight unit. RAX-2 was delivered for launch in September 2011, launched October 28, 2011, and is currently operating in low-Earth orbit.
With the exception of the solar panels, the designs of RAX-1 and RAX-2 are largely identical, and RAX information on this website applies to both satellites. Learn more about RAX at these links below…
Mission Overview || Mission Science || Spacecraft Design || Testing
(Banner image © RAX Team)
