$100 million Breakthrough Starshot small interstellar probe project will start funding technological development in a few months
by noreply@blogger.com (brian wang) from NextBigFuture.com on (#2B3X7)
The Breakthrough Starshot is an effort backed by US$100 million from Russian investor Yuri Milner to vastly accelerate research and development of an interstellar space probe.
Leaders of the mission plan to start funding technology-development projects within months, with the aim of launching a fleet of tiny, laser-propelled probes in the next 20 years. The effort would ultimately cost about $10 billion, leaders hope, and take another 20 years to reach Alpha Centauri.
The first truly challenging step in any mission such as Breakthrough Starshot is to accelerate the spacecraft to interstellar velocities.
Researchers at the Japan Aerospace Exploration Agency (JAXA) and the Planetary Society have deployed solar sails in space. An advanced solar sail could theoretically reach about 13% of the speed of light if it could withstand high temperatures and was ultrathin and performed a gravitational slingshot move around the sun that passed within a couple of solar radii. The materials for such a sail do not yet exist (at least in sufficient quantities).
NOTE - a recent paper shows how a gravity slingshot could be used to decelerate an interstellar probe travelling at 4.6% of lightspeed into a parking orbit in a target solar system
A Laser propelled sail has not been demonstrated in space and is required for the required speeds of about 25% of light speed.
The Starshot team plans to use conventional rockets to send its probes into orbit. Then a 100-gigawatt laser array on Earth would fire continuously at the sail for several minutes, long enough to accelerate it to 60,000 kilometers per second
Starshot leaders acknowledge that they are counting on breakthroughs from the laser industry. One hundred gigawatts will be a million times more powerful than today's biggest continuous lasers, which put out hundreds of kilowatts. One way around that gap would be to combine light from hundreds of millions of less powerful laser beams across an array that is at least a kilometer wide. But the beams would all need to be brought into phase with each other so that their light waves add rather than cancel each other out - making the lasers one of the mission technologies that requires the most development work.
Whatever the design, the sail must be strong. A 100-gigawatt laser beam will hit it hard, generating tens of thousands of times the acceleration that an object feels on Earth owing to gravity. Artillery shells have survived such forces in military tests, Worden notes, but for less than a second - not the several minutes for which the laser will pound the device.
Starshot's plan would build strength in numbers. The spacecraft would be small and relatively low-cost, so the project could launch one or more every day, and even afford to lose some of them.
Development of the probes will proceed in stages, says Worden. The first step is to build a prototype system that would accelerate to perhaps 1,000 kilometers per second - less than 2% of the speed planned for Starshot - for a total cost between $500 million and $1 billion.
The craft
The Starshot craft will look like nothing ever launched into space. Imagine a small collection of electronics, sensors, thrusters, cameras and a battery on a roughly one-centimetre-wide chip in the centre of a circular or square sail, roughly 4 metres wide - all weighing just a gram. The lighter the craft, the faster a given force can accelerate it.
Here is a 68 page roadmap by Philip Lubin of the University of Santa Barbara for developing laser pushed sails.
Lubin's designs would enable wafersats to reach 25% of lightspeed and a 100 ton spaceship to reach 1000 kilometers per second.
Nextbigfuture notes that for manned missions going beyond 1000 km per second, the wafer chips could be accelerated at a manned ship with a pusher plate (like the Project Orion ship) but the energy would be kinetic and not nuclear.
For large object construction, we need to develop the Tether Unlimited Spiderfab technology. This is construction in space with robots which means systems can be lighter and bigger like robots assembling an outdoor tent of sticks in space instead of building something on the ground and making it tough enough to withstand 3Gs or more of acceleration at launch.
They propose a roadmap to a program that will lead to sending relativistic probes to the nearest stars and will open up a vast array of possibilities of flight both within our solar system and far beyond. Spacecraft from gram level complete spacecraft on a wafer ("wafersats") that reach more than 1/4 c and reach the nearest star in 20 years to spacecraft with masses more than 100,000 kg (100 tons) that can reach speeds of greater than 1000 km/s. These systems can be propelled to speeds currently unimaginable with existing propulsion technologies. To do so requires a fundamental change in our thinking of both propulsion and in many cases what a spacecraft is. In addition to larger spacecraft, some capable of transporting humans, we consider functional spacecraft on a wafer, including integrated optical communications, imaging systems, photon thrusters, power and sensors combined with directed energy propulsion. The costs can be amortized over a very large number of missions beyond relativistic spacecraft as such planetary defense, beamed energy for distant spacecraft, sending power back to Earth, stand-off composition analysis of solar system targets, long range laser communications, SETI searches and even terraforming. The human factor of exploring the nearest stars and exo-planets would be a profound voyage for humanity, one whose non-scientific implications would be enormous. It is time to begin this inevitable journey far beyond our home.
Photon propulsion is an old idea going back many years, with some poetic references several hundred years ago. A decade ago what they now propose would have been pure fantasy. It is no longer fantasy. Recent dramatic and poorly-appreciated technological advancements in directed energy have made what we propose possible, though difficult. There has been a game change in directed energy technology whose consequences are profound for many applications including photon driven propulsion. This allows for a completely modular and scalable technology with radical consequences
The photon driver is a laser phased array which eliminates the need to develop one extremely large laser and replaces it with a large number of modest (kW class) laser amplifiers that are inherently phase locked as they are fed by a common seed laser. This approach also eliminates the conventional optics and replaces it with a phased array of small optics that are thin film optical elements. Both of these are a follow on DARPA and DoD programs and hence there is enormous leverage in this system. The laser array has been described in a series of papers we have published and is called DE-STAR (Directed Energy System for Targeting of Asteroids and ExploRation). Powered by the solar PV array the same size as the 2D modular array of modest and currently existing kilowatt class Yb fiber-fed lasers and phased-array optics it would be capable of delivering sufficient power to propel a small scale probe combined with a modest (meter class) laser sail to reach speeds that are relativistic. DE-STAR units are denoted by numbers referring to the log of the array size in meters (assumed square). Thus DE-STAR-1 is 10 meters on a side, -2 is 100 meters, etc. Photon recycling (multiple bounces) to increase the thrust is conceivable and has been tested in our lab but it NOT assumed. The modular sub systems (baselined here at 1-4 meters in diameter) fit into current rocket launchers
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Leaders of the mission plan to start funding technology-development projects within months, with the aim of launching a fleet of tiny, laser-propelled probes in the next 20 years. The effort would ultimately cost about $10 billion, leaders hope, and take another 20 years to reach Alpha Centauri.
The first truly challenging step in any mission such as Breakthrough Starshot is to accelerate the spacecraft to interstellar velocities.
Researchers at the Japan Aerospace Exploration Agency (JAXA) and the Planetary Society have deployed solar sails in space. An advanced solar sail could theoretically reach about 13% of the speed of light if it could withstand high temperatures and was ultrathin and performed a gravitational slingshot move around the sun that passed within a couple of solar radii. The materials for such a sail do not yet exist (at least in sufficient quantities).
NOTE - a recent paper shows how a gravity slingshot could be used to decelerate an interstellar probe travelling at 4.6% of lightspeed into a parking orbit in a target solar system
A Laser propelled sail has not been demonstrated in space and is required for the required speeds of about 25% of light speed.
The Starshot team plans to use conventional rockets to send its probes into orbit. Then a 100-gigawatt laser array on Earth would fire continuously at the sail for several minutes, long enough to accelerate it to 60,000 kilometers per second
Starshot leaders acknowledge that they are counting on breakthroughs from the laser industry. One hundred gigawatts will be a million times more powerful than today's biggest continuous lasers, which put out hundreds of kilowatts. One way around that gap would be to combine light from hundreds of millions of less powerful laser beams across an array that is at least a kilometer wide. But the beams would all need to be brought into phase with each other so that their light waves add rather than cancel each other out - making the lasers one of the mission technologies that requires the most development work.
Whatever the design, the sail must be strong. A 100-gigawatt laser beam will hit it hard, generating tens of thousands of times the acceleration that an object feels on Earth owing to gravity. Artillery shells have survived such forces in military tests, Worden notes, but for less than a second - not the several minutes for which the laser will pound the device.
Starshot's plan would build strength in numbers. The spacecraft would be small and relatively low-cost, so the project could launch one or more every day, and even afford to lose some of them.
Development of the probes will proceed in stages, says Worden. The first step is to build a prototype system that would accelerate to perhaps 1,000 kilometers per second - less than 2% of the speed planned for Starshot - for a total cost between $500 million and $1 billion.
The craft
The Starshot craft will look like nothing ever launched into space. Imagine a small collection of electronics, sensors, thrusters, cameras and a battery on a roughly one-centimetre-wide chip in the centre of a circular or square sail, roughly 4 metres wide - all weighing just a gram. The lighter the craft, the faster a given force can accelerate it.
Here is a 68 page roadmap by Philip Lubin of the University of Santa Barbara for developing laser pushed sails.
Lubin's designs would enable wafersats to reach 25% of lightspeed and a 100 ton spaceship to reach 1000 kilometers per second.
Nextbigfuture notes that for manned missions going beyond 1000 km per second, the wafer chips could be accelerated at a manned ship with a pusher plate (like the Project Orion ship) but the energy would be kinetic and not nuclear.
For large object construction, we need to develop the Tether Unlimited Spiderfab technology. This is construction in space with robots which means systems can be lighter and bigger like robots assembling an outdoor tent of sticks in space instead of building something on the ground and making it tough enough to withstand 3Gs or more of acceleration at launch.
They propose a roadmap to a program that will lead to sending relativistic probes to the nearest stars and will open up a vast array of possibilities of flight both within our solar system and far beyond. Spacecraft from gram level complete spacecraft on a wafer ("wafersats") that reach more than 1/4 c and reach the nearest star in 20 years to spacecraft with masses more than 100,000 kg (100 tons) that can reach speeds of greater than 1000 km/s. These systems can be propelled to speeds currently unimaginable with existing propulsion technologies. To do so requires a fundamental change in our thinking of both propulsion and in many cases what a spacecraft is. In addition to larger spacecraft, some capable of transporting humans, we consider functional spacecraft on a wafer, including integrated optical communications, imaging systems, photon thrusters, power and sensors combined with directed energy propulsion. The costs can be amortized over a very large number of missions beyond relativistic spacecraft as such planetary defense, beamed energy for distant spacecraft, sending power back to Earth, stand-off composition analysis of solar system targets, long range laser communications, SETI searches and even terraforming. The human factor of exploring the nearest stars and exo-planets would be a profound voyage for humanity, one whose non-scientific implications would be enormous. It is time to begin this inevitable journey far beyond our home.
Photon propulsion is an old idea going back many years, with some poetic references several hundred years ago. A decade ago what they now propose would have been pure fantasy. It is no longer fantasy. Recent dramatic and poorly-appreciated technological advancements in directed energy have made what we propose possible, though difficult. There has been a game change in directed energy technology whose consequences are profound for many applications including photon driven propulsion. This allows for a completely modular and scalable technology with radical consequences
The photon driver is a laser phased array which eliminates the need to develop one extremely large laser and replaces it with a large number of modest (kW class) laser amplifiers that are inherently phase locked as they are fed by a common seed laser. This approach also eliminates the conventional optics and replaces it with a phased array of small optics that are thin film optical elements. Both of these are a follow on DARPA and DoD programs and hence there is enormous leverage in this system. The laser array has been described in a series of papers we have published and is called DE-STAR (Directed Energy System for Targeting of Asteroids and ExploRation). Powered by the solar PV array the same size as the 2D modular array of modest and currently existing kilowatt class Yb fiber-fed lasers and phased-array optics it would be capable of delivering sufficient power to propel a small scale probe combined with a modest (meter class) laser sail to reach speeds that are relativistic. DE-STAR units are denoted by numbers referring to the log of the array size in meters (assumed square). Thus DE-STAR-1 is 10 meters on a side, -2 is 100 meters, etc. Photon recycling (multiple bounces) to increase the thrust is conceivable and has been tested in our lab but it NOT assumed. The modular sub systems (baselined here at 1-4 meters in diameter) fit into current rocket launchers
Read more