posted 06-20-2017 06:37 PM               

Over the weekend of June 17-18, 2017, engineers on the ground remotely operated the International Space Station's robotic Canadarm2 to extract the Roll Out Solar Array (ROSA) experiment from the SpaceX Dragon resupply ship. The experiment will remain attached to the Canadarm2 over seven days to test the effectiveness of ROSA, an advanced, flexible solar array that rolls out like a tape measure.

Traditional solar panels used to power satellites can be bulky with heavy panels folded together using mechanical hinges. This new solar array's design rolls up to form a compact cylinder for launch with significantly less mass and volume, potentially offering substantial cost savings as well as an increase in power for satellites.

ROSA was developed as part of the Solar Electric Propulsion project sponsored by NASA’s Space Technology Mission Directorate. NASA tested the ROSA technology in vacuum chambers on Earth several years ago, and this is its first test in space. This solar array technology was developed to power large spacecraft using highly-efficient electric propulsion on missions to deep space including Mars and the moon.

posted 06-26-2017 06:59 PM               

An experimental solar array demonstration was jettisoned while the Expedition 52 crew continued preparing the SpaceX Dragon for its release on Sunday (July 2).

Following a week of successful science operations on the experiment for the Roll-Out Solar Array (ROSA), attempts to retract the array were unsuccessful. The ISS Mission Management Team met Monday morning and made the decision to jettison ROSA directly from its location at the end of the space station's robotic arm, where it remained fully deployed in a normal configuration.

The original plan called for ROSA to be stored back inside the trunk of SpaceX's Dragon which is detached and burned up in the atmosphere during Dragon reentry. The Operations team executed the jettison procedure that was developed as part of the pre-flight planning process that covered various scenarios. Once jettisoned, ROSA will not present any risk to the International Space Station and will not impact any upcoming visiting vehicle traffic.

posted 07-03-2017 05:57 PM               

The ROSA array (Roll-Out Solar Array) is similar in design to the Hubble solar array. It possesses a flexible blanket that is rolled on a drum for stowage and is supported by two STEM booms running along the blanket edges. The booms are rolled on the same drum and deployed in parallel with the blanket.

In contrast to Hubble, a tip-deployment is applied instead of the root deployment. Thereby the drum can also be used as a spreader bar to stretch the blanket and connect both booms. The energy for the deployment process is provided by the strain energy stored in the two carbon fiber STEM booms. Therefore no additional motor is required except for deployment control reasons. The overall design of ROSA is strongly focused on simplicity.