NASA gives all-clear: the wobbly solar sail satellite ACS3 is working normally
The ACS3 solar sail satellite is tumbling. What looks like a defect is actually quite normal, say NASA researchers.
An artist's impression of the ACS3 with its awning.
(Image: NASA / Aero Animation / Ben Schweighart)
According to the US space agency NASA, the experimental solar sail satellite ACS3 (Advanced Composite Solar System 3), which was launched into space on April 24, is functioning completely normally after deploying its solar sail. This was announced by the agency on Thursday. It had previously been observed that the spacecraft, which was orbiting the Earth, was wobbling and spinning.
The movements of the ACS3 are not unusual, according to NASA's Langley Research Center. "Our solar sail system is orbiting the Earth and tumbling slowly, as expected, while the mission team observes its boom and sails."
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The 80 m² sail of ACS3, which was developed at the Langley Research Center, was deployed in Earth orbit last week. It is an experiment designed to explore how future spacecraft can be propelled effectively without fuel. The ACS3 uses the pressure generated by solar radiation to propel itself. As the pressure from the sun's rays is low, the solar sail must be designed to be large enough to generate sufficient thrust.
Special outriggers for the awning
The ACS3 uses composite materials with different properties. The awning itself is less interesting. Rather, it is the outriggers to which the sail is attached. They are made of a polymer material that is reinforced with carbon fibers and designed to be flexible. This means that the outriggers can be rolled up together with the sail to save space during transportation with the rocket. The booms are highly rigid when rolled out. They are protected against warping due to temperature fluctuations and cannot be bent.
NASA scientists have also tested a special reel for the deployment system on the ACS3. It is designed to minimize jamming of the rolled-up booms during deployment.
The ACS3 is now collecting data on how well the system works. An evaluation of the data should then show how future, larger solar sail systems made of composite materials need to be constructed in order to generate effective thrust. They could be used in space weather early warning systems, in near-Earth asteroid reconnaissance missions and in communication relays for manned exploration missions.
(olb)
