Tag: Advanced Composite Solar Sail System

A slight bend in one boom delays NASA solar sail flight

9:07 am

Even though NASA’s solar sail test mission, dubbed the Advanced Composite Solar Sail System (ACSSS), successfully unfolded its giant sail in late August, engineers have not yet reactivated the sail’s attitude control system because they have detected a slight bend in one of the sail’s four booms.

While the solar sail has fully extended to its square shape roughly half the size of a tennis court, the mission team is assessing what appears to be a slight bend in one of the four booms. This likely occurred as the booms and sail were pulled taut to the spacecraft during deployment. Analysis indicates that the bend may have partially straightened over the weeks since boom deployment, while the spacecraft was slowly tumbling.

The attitude control system was turned off as planned during the deployment, allowing the sail to slowly tumble. It has been kept off longer than expected because the tumbling appears to be helping straighten the bend.

Once the control system is reactivated, the mission will then attempt to use the sail to change its orbit, to actually fly in space using sunlight like the wind.

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NASA confirms its giant solar sail is tumbling but doing so as planned

9:04 am

NASA today outlined the testing that its engineers are doing with the deployed 860 square foot Advanced Composite Solar Sail System (AC3), including the planned tumbling that an amateur astronomer detected based on the fluctuating brightness of the sail.

Currently orbiting Earth, the spacecraft can be seen with its reflective sails deployed from the ground. As part of the planned deployment sequence, the spacecraft began flying without attitude control just before the deployment of the booms. As a result, it is slowly tumbling as expected. Once the mission team finishes characterizing the booms and sail, they will re-engage the spacecraft’s attitude control system, which will stabilize the spacecraft and stop the tumbling. Engineers will then analyze flight dynamics before initiating maneuvers that will raise and lower the spacecraft’s orbit.

The release adds that NASA has added a feature to its mobile app that will help anyone spot the sail in the night sky.

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Amateur astronomer detects changes in the reflective light coming off of NASA’s orbiting solar sail

10:20 am

Observations by amateur astronomer Marco Langbroek of Delft Technical University in the Netherlands has detected significant changes in the reflective light coming off of the giant orbiting solar sail that NASA engineers recently deployed in orbit.

I observed the Solar Sail again in the evening of September 1, 2024, and this time the brightness of the Solar Sail was quite different. As it rose in the south, it became very bright, reaching magnitude 0 (as bright as the brightest stars in the sky). It then faded again, and next displayed a slow brightness variation with multiple bright maxima and very faint minima.

…The brightness seems to indicate a slow cycle of around half a minute. … The brightness variation could be suggestive of a slow tumble or wobble (a gyration around an axis) that must have been initiated after August 29, when it appeared more steady (apart from a brief bright flare, probably due to a favourable sun-sail-observer geometry).

The sail, dubbed the Advanced Composite Solar Sail System, was launched on April 23rd, and after some initial technical issues it was deployed from its small cubesat on August 30th, expanding to 860 square feet.

The changes Langbroek detected have all occurred after that deployment, and suggest one of two things. Either the NASA engineers are testing the sail’s maneuverability, as planned, and thus the sunlight reflecting off it changes, or there is a problem controlling it that NASA has not yet revealed. We will have to wait to find out.

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NASA solar sail successfully deploys

9:03 am

After experiencing a technical issue that initially delayed deployment, NASA engineers have now successfully deployed the boom of the 860-square-foot solar sail that had been launched in a cubesat only about four feet in size.

NASA’s Advanced Composite Solar Sail System is now fully deployed in space after a successful test of its sail-hoisting boom system. Mission operators confirmed success at 1:33 p.m. EDT (10:33 a.m. PDT) on Thursday, Aug. 29, after receiving data from the spacecraft. Centrally located aboard the spacecraft are four cameras which captured a panoramic view of the reflective sail and supporting composite booms. High-resolution imagery from these cameras will be available on Wednesday, Sept. 4.

The next step will be to test the sail’s ability to maneuver in space, including raising and lowering its orbit using the pressure of sunlight, just like sailboats use the wind.

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