We need to make bigger solar sails from materials that can take high temperatures. Taking high temperatures means the solar sails could fly closer to the sun. If we got four times closer to the sun than Mercury (9 million miles or so )then we could go 20AU per year which is about 3 times faster than any spacecraft we have made. If we could go to about 2 million miles from then we could go to 50-60AU per year speeds.
NASA is testing solar sail with boom structures that could make solar sails about 20 times bigger. This means demonstration of the technologies needed to fabricate, fly, navigate and control 100 – 200 kg class missions using sails in the 1,500 to 7,000-m2 class. These are being developed and ground tested. A proposed Solar Cruiser mission was canceled in 2022.
Technologies and Materials
Close solar approach in future missions will require novel solar sail materials. New Liquid Crystal Polymer film technology appears to possess the very low absorption manufacturability and toughness required. The long-chain molecules in these nematic crystals are optically birefringent, slowing light polarized along the long axis of the molecule compared to the short axis, their properties can be tailored to affect the force, and torque response without a change is macroscopic shape with lower power requirements than other methods.
Monolayer graphene and graphene based composites offer advantages for these future systems. Graphene, for example, has low aerial density and provides much higher tensile strength and temperature capability up-to 4,000 K. Atomically thin graphene is examined as a promising stand-alone material for solar sails owing to its extremely low areal density making it ideal for extremely large sails that require close perihelion approaches.
Other light, high-temperature materials such as aerographite are also under consideration. Further, ceramics, such as silicon nitride and silicon dioxide, are naturally transparent with very low losses in the visible and ultraviolet. These materials are refractory and possess high melting points (>2000K) making them potentially applicable for close perihelion approaches (4 − 20 solar radii) with minimal degradation.
Close approach can be used to accelerate solar sails to unprecedented velocities – for example, a sail with a characteristic acceleration ≃ 3 mm/s2 performing an Oberth maneuver at 0.1AU perihelion may be accelerated to >20AU/yr cruise velocity and accelerations to 50AU/year are projected with new advance materials.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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50 AU per year would be great for a telescope to do stellar parallax.
https://www.nasa.gov/solar-system/nasas-new-horizons-conducts-the-first-interstellar-parallax-experiment/
Shocking. Do people really believe that these gossamer craft of any useful size and shape can survive any prolonged period over any reasonable distance travelled beyond the inner planets?
Yes. Travelling between the inner planets, will be more “turbulent” and risky then going beyond them. If we design materials that repair themselves and adapt, I think we’ll be OK…
Perhaps solar sails, powered by the sun or lasers, need to be optimized to translate the imparted photons into optimum momentum. To me, this says we need to get the material of the sail “right”. An adaptive material, that changes based on the distance-from-source, frequency and total imparted energy, makes sense. After all, you want to exploit whatever energy you get, in the most efficient way. Close to the sun, or a laser source, your going to have a high volume or “clustered” photons. Distance reduces this (well, duh). Your “sail” needs to adapt, or morph, to accommodate this reality.
It’s also about a 4,000 uear trip to Alpha Centauri
60 au is booking it. Voyager 1 is 15 billion miles from the sun so it could probably catch up to it in maybe 4 years (6 billion miles/yr, on a non linear path)
50 AU/year means 11-12 years to the Sun’s gravity lens.
And the speed itself is not a problem, given the lens gets better with distance up to really long distances. As long as the probe remains on the remote object focus beam, so an ion drive for correction ought to be enough for a few years worth of observations.
The problem starts becoming one of communication with those distances. At 600 AU its like 3 days and several hours light.