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Drama in Low-Earth Orbit as LightSail 2 Deploys its Sails:
LightSail 2 has successfully deployed its solar sails. Shortly after 12:00 pm PST The Planetary Society tweeted that the sails were deployed, and that the spacecraft was sailing with sunlight. We can all enjoy their success and start to wonder how solar sails will fit into humanity's plans for space exploration.
[...] This is a dramatic moment for LightSail 2 and for The Planetary Society, the world's largest non-profit space organization. LightSail 2 is the third spacecraft in their LightSail program. It was launched on June 25th, and has been in orbit since then, preparing for sail deployment and sending us some sweet pictures of Earth.
[...] LightSail 2's sail is actually a system of four smaller triangular sails that make one large square when deployed. Once deployed, the sail measures 32 sq. meters, or 340 sq. ft. Once it's deployed, it can be used to raise the spacecraft's orbit, demonstrating the power and usefulness of solar sails.
[...] In some ways, the solar sail is exactly like a sail on a boat. The sail can be aimed at angles, to direct the travel of the spacecraft. If the sails are aimed directly at the Sun, the spacecraft will travel directly away from the Sun. But by tacking, or changing the angle of the sails, a spacecraft using solar sails can steer and propel itself through the Solar System and beyond.
Planetary Society Twitter feed.
Also at: The Register, NYT, and The Verge.
Previously:
Planetary Society Receiving Data From LightSail 2
One Legacy of Carl Sagan May Take Flight Next Week—a Working Solar Sail
Planetary Society's "LightSail" Solar Sail Test Launch on May 20
(Score: 2) by aristarchus on Thursday July 25 2019, @12:51AM (3 children)
No, you would not. This is the problem. Even a beam reach is not possible for a solar sail!
(Score: 2) by deimtee on Thursday July 25 2019, @03:57AM (2 children)
Not perpendicular, but definitely off-axis.
There are two components to the momentum transfer. One is the direct impingement which is always on the sun-sail line. The other is in the opposite direction to the direction of the reflected beam. If the sail is at an angle of 45° to the sun, the beam will leave at 90° to its original line, giving an effective direction of thrust 45° off the sun-sail line. You can't directly tack 'upwind', but you can increase or decrease your orbital speed which has the same effect.
Another way is if you are in orbit around anything other than the sun you can simply wait until the direction of thrust you want is along the sun-sail line. In reality, you would use the best combination of both.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 2) by aristarchus on Thursday July 25 2019, @06:28AM (1 child)
My only point. Of course, if your impulse away from the Solar mass exceeded the reduction in orbital velocity, you may not end up where you thought you would be. I recommend a close reading of the Odyssey, navigational errors can result in you being stranded with nymphs (Callisto), or Goddesses (Circe), or planets (Europa). Sailing is not a way of life for the faint of heart!
(Score: 0) by Anonymous Coward on Thursday July 25 2019, @01:35PM
Ay me hearty. But even an impressed man will learn the ropes in time.