Solar sail how fast

LightSail 2 uses 4 triangular Mylar sails that are just 4. They unfold using 4 cobalt alloy booms that unwind like tape measures. The sails have a combined area of 32 square meters square feet , about the size of a boxing ring. There is theoretically no minimum size for a solar sail, but for the same mass spacecraft, bigger sails will capture more sunlight and accelerate the spacecraft more quickly. This is equivalent to a square of meters half-mile by meters — the size of 10 square blocks in New York City!

Of course, the practicality of building and deploying such an enormous sail is questionable. But if such a sail could be successfully developed, amazing destinations could be reached. A bigger sail captures more sunlight, gaining more momentum and accelerating more quickly for the same mass. For a given sail size, a lower mass spacecraft will have a higher acceleration. The acceleration also depends on its distance from a light source and strength of the light source.

As a solar sail spacecraft gets farther away from the Sun, the amount of sunlight available to it decreases, meaning that it accelerates less quickly. Theoretically, powerful lasers could be aimed at a distant solar sail, providing some extra acceleration as the spacecraft gets further from the Sun. Larger sails, or small sails accelerated by lasers, could theoretically go much faster.

In , the group Breakthrough Initiatives announced a plan to send a fleet of tiny, laser-powered solar sails to our nearest star, Alpha Centauri. The spacecraft would be targeted in space by Earth-based lasers, and accelerate to 20 percent the speed of light.

Building a solar sail, especially a very large one, is a feat that still needs development. And that research and development can be expensive. But once solar sails are better tested and understood, they could be a relatively inexpensive means of propulsion. Solar sails have a reflective layer which reflects the light particle, which produces even more momentum as it pushes off the reflective layer. As momentum hits the solar sail it gives off a force, this force value is based on the reflectivity value of the reflective material and solar energy that hits the solar sail.

The problem here does not take into account for gravitational forces, non perfect reflective surface, emissivity layer, and estimated atmospheric drag.

Substituting mdv into the equation and mulitple the momentum by a factor of 2. This is due to the reaction momentum. Exploring Solar Sails. Solar Sails The math behind solar sails. Introduction Solar Sail Physics. Diagrams Light reflecting off Solar Sail. Images done by Robert Miller. Reflection Layer. Case Reaction Force. Light Source.

Reaction Momentum. Forces and Momentum How it works. Initial Momentum The initial momentum is the momentum of protons from a light source. Reaction Momentum Reaction momentum is the reaction from the initial momentum from the light source. Reaction Force The reaction force is thermal energy which is due to the solar sail being heated up.

With the advent of smart phones and the miniaturization of components, we're now able to make really lightweight, small spacecraft, which makes the size of the sail more reasonable.

In particular, Johnson points to the development of CubeSats —boxy mini-satellites designed to use off-she-shelf technology. The NEA Scout will be a CubeSat roughly the size of a large shoebox, propelled by a solar sail measuring square feet 86 square meters. Despite its modest size, the probe is packed with enough instruments to conduct an extensive survey of asteroid VG, taking pictures and measuring its chemical composition, size, and motion.

NASA sees such reconnaissance as an essential first step for future crewed missions to asteroids. Likewise, the space agency needs to know ahead of time whether the asteroid is a solid object or a pile of rubble held together by gravity. There are various ways do this, using the celestial equivalents of masts and rigging.

IKAROS had an electro-optic coating that went dark when voltage was applied, absorbing light instead of reflecting it. The NEA Scout will take a different approach, using a sliding mechanism that moves the CubeSat back and forth relative to the booms where the sail is deployed. That's what we're going to be doing. The agility of solar sail spacecraft—coupled with the constant thrust from an inexhaustible supply of fuel—opens the door to some intriguing possibilities.

In order to achieve the drastic change in direction and velocity—without using precious propellant—engineers would rely on a slingshot maneuver.

At present, if you want a satellite to remain in a fixed position relative to a certain location on the ground—which is highly desirable for communications technology—your only option is to send it into geostationary orbit, 22, miles above the Earth and directly above the equator. That way, you appear motionless above the North or South Pole. NASA researchers have recently received more funding to investigate an advanced concept for a superfast sail propelled by charged particles in the solar wind.

The idea, first proposed by Pekka Janhunen, a researcher at the Finnish Meteorological Institute, envisions a spacecraft encircled by 20 hair-thin wires that are each 12 miles 20 kilometers long.

The wires generate a positively charged electrical field extending dozens of meters into space. Protons in the solar wind, traveling at speeds as high as miles per second kilometers per second , are repelled by this electric field, thrusting the spacecraft forward as they are pushed away. The e-sail would have plenty of fuel.

While the sunlight that propels a solar sail significantly diminishes once a spacecraft reaches the asteroid belt, the solar wind is still blowing strong. That means space probes could reach Jupiter in just two years, or Pluto in five.

E-sails could enable an entirely new opportunity for exploration by providing express travel beyond the solar system, into interstellar space. By way of comparison, it took the Voyager I spacecraft 35 years to reach the boundary of the solar system. A solar sail could make the same trip in 20 years, while an e-sail would arrive in just In fact, Wiegmann believes that a prototype could be launched in five years. In the meantime, some key issues need to be addressed. Although an e-sail doesn't need fuel, it requires a power source for the electron gun that expels electrons.

How much power would an e-sail need? That depends on the number of electrons that the e-sail collects. NASA researchers are studying the question with charged wire in a plasma chamber that simulates the solar wind.