Tag: solar sail

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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NASA reveals technical problem during solar sail deployment of test mission

9:32 am

NASA today revealed that a technical problem occurred during the deployment of a demonstration solar sail mission launched in April on Rocket Lab’s Electron rocket.

Upon an initial attempt to unfurl, the solar sail paused when an onboard power monitor detected higher than expected motor currents. Communications, power, and attitude control for the spacecraft all remain normal while mission managers work to understand and resolve the cause of the interruption by analyzing data from the spacecraft.

The goal had been test the boom deployment of a 860 square foot sail from a cubesat only about 4 feet in size.

The concept of the solar sail is simple: Use the pressure produced by sunlight to maneuver and fly controlled throughout the solar system. The idea has been tested successfully several times, with the Japanese IKAROS test solar sail and the Planetary Society’s Lightsail-2 the most successful. Sadly almost all other attempts to test this idea have had technical problems of one kind or another.

Ironically, one test solar sail proved that such a deployment from a cubesat could be done very cheaply, unlike NASA’s effort above. Brown University students in 2023 used cheap off-the-shelf parts to launch a smallsat sail that successfully deployed and was then used to lower the satellite’s orbit in order to de-orbit it more quickly. Total cost, $10,000. And it worked.

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ESA successfully unfurls solar sail from cubesat

9:32 am

The European Space Agency (ESA) has successfully unfurled a solar sail from a cubesat in order to test using that sail to help de-orbit that cubesat more quickly.

The sail was deployed from a package measuring 3.93 by 3.93 by 3.93 inches (10 by 10 by 10 centimeters). The unfurling process was captured by an integrated camera onboard the Ion satellite carrier, which is operated by the Italian company D-Orbit.

The satellite will eventually burn up in the atmosphere, providing a quicker, residue-free method of disposal, according to ESA.

A short video of that unfurling can be viewed here.

This flight was intended as a proof of concept. Thus, ESA like many similar NASA test projects will now close the project down, which is dubbed ADEO, having no specific plans to do anything with what was learned. Private cubesat companies, however, might adopt this solar sail deployment technology, but I suspect less for de-orbit purposes but instead as a method of maneuvering their satellite in orbit.

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LightSail-2 completes three-plus year mission, burning up in atmosphere

9:44 am

LightSail-2 sail deployed
LightSail-2, shortly after deployment in 2019.

LightSail-2, an experimental solar sail built by the Planetary Society, finally ended its mission this week, with the test sail burning up in the atmosphere upon re-entry.

LightSail 2 was launched aboard a SpaceX Falcon Heavy rocket in June 2019, settling into an initial orbit at an altitude of around 720 km (450 miles). At that height, the Earth’s atmosphere is still thick enough to create drag, which would threaten to eventually pull the spacecraft down.

But that’s where the plucky little satellite’s special ability came in. Although it’s only the size of a shoebox, LightSail 2 unfurled a big reflective sheet, called a solar sail, about the size of a boxing ring. The idea is that photons from sunlight strike this sail and generate tiny amounts of thrust, allowing the craft to change its orbit.

And LightSail 2 demonstrated this concept beautifully. In three and a half years, the spacecraft completed around 18,000 orbits and traveled 8 million km (5 million miles), adjusting its orbit continuously to keep itself aloft. But all good things must come to an end, and sometime on November 17, drag finally won the tug-of-war and pulled the spacecraft back to Earth.

LightSail-2 was the third time a light sail had been flown in space, with the first, Ikaros, deployed by the Japanese in 2010 and flown in solar orbit through 2012. That mission was successful in using sunlight to accelerate the sail. This was followed by LightSail-1 in 2015. That mission has some communications problems, but eventually succeeded in its main engineering mission by testing the sail deployment system.

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LightSail deploys its solar sails

10:48 pm

Though full confirmation will not come until later tonight, telemetry from LightSail suggests that its solar sails have successfully begun deployment.

Telemetry received on the ground showed motor counts climbing to the halfway point before LightSail traveled out of range. Power levels were consistent with ground-based deployment tests, and the spacecraft’s cameras were on. “All indications are that the solar sail deployment was proceeding nominally,” wrote mission manager David Spencer in an email update.

They will have to wait until the cubesat comes back in range at 2:46 am (Eastern) to see if the deployment completed successfully, as well as download images.

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LightSail deployment scheduled for Tuesday

7:54 am

Assuming all goes well with the orbital preparations today, LightSail will perform its test deployment on Tuesday at 11:44 am.

If successful, this deployment will achieve several significant engineering firsts, the most important of which will be to have demonstrated that a cubesat can be used for such a task. Proving that fact will increase their commercial usefulness for future space endeavors.

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Solar sail experiment stymied by software crash

10:14 pm

The Planetary Society’s LightSail solar sail test mission, launched as a secondary payload on last week’s Atlas 5 X-37B launch, has fallen silent because of a software problem.

The communications problem occurred before the mission could achieve its main engineering goal of testing the deployment of the solar sail. They still hope to regain communications, but time is limited as the cubesat is in a low orbit that will decade relatively quickly.

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Sunjammer, NASA’s next solar sail experiment.

9:06 am

Sunjammer, NASA’s next solar sail experiment.

Though the article headline focuses on the addition of space weather instruments to this solar sail, the article says very little about those instruments. One, Swan, is described as a “wind instrument”, which probably means it would study the solar wind. The other instrument would study the Earth’s magnetic field. Both instruments are needed to track the effect of the Sun on local space weather, since the one satellite we have to do this, Ace, is now more than a decade past its expiration date.

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Nanosail-D has sailed home, burning up in the atmosphere on September 17

9:14 pm

The solar sail Nanosail-D has sailed home, burning up in the atmosphere on September 17.

The flight phase of the mission successfully demonstrated a deorbit capability that could potentially be used to bring down decommissioned satellites and space debris by re-entering and totally burning up in the Earth’s atmosphere. The team continues to analyze the orbital data to determine how future satellites can use this new technology.

The concept being tested appears to use a solar sail as a navigating tool for guiding defunct satellites back into the atmosphere.

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Using a solar sail to deflect an earth-destroying asteroid

10:35 am

solar sail mission to Apophis

In a paper published today on the Los Alamos astro-ph preprint website, two Chinese scientists have proposed using a solar sail for deflecting any asteroid that happens to be aimed at the earth. The diagram to the right is their simulated mission to impact the asteroid Apophis, which will pass close to the earth in 2029 and — depending on whether that flyby puts it through a very small 600 meter-wide mathematical “keyhole” — could then return in 2036 on a collision course.

The idea is to use the sail to slow the spacecraft down enough so that it starts to fall towards the sun. The sail is then used to maneuver it into a retrograde orbit. When it impacts the asteroid the impact will therefore be similar to a head-on collision, thereby imputing the most energy in the least amount of time with the least amount of rocket fuel. In their Apophis simulation, a mission, weighing only 10 kilograms (about 22 pounds), launched around 2025, and hitting the asteroid in this manner in 2026, would deflect its flyby in 2029 enough to guarantee it will not fly through the “keyhole” and therefore eliminate any chance of it hitting the earth in 2036.

Obviously many questions must be answered before such a mission should fly.
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