The journey to Mars has been a long time coming, but the recent interest in going to the Red Planet has spurred many developments in space travel and exploration. New technologies have made it possible to travel to other planets and moons, and interest in interplanetary exploration has seen the establishment of numerous space agencies worldwide. Spacecrafts have evolved from being little more than a handful of satellites to now including fully crewed rovers, landers, and even manned spacecraft.
What will these spacecraft need to function in space? A reliable power source is a priority, as is the ability to transmit signals and data back to Earth. The Sun provides a virtually limitless and constant power source for space-based operations, so the next logical step has been to utilize its energy to propel crafts through space.
Solar Wind is the solar-powered satellite architecture that has been designed to harness the sun’s rays for propulsion and energy.
What is a satellite, anyway? A satellite is a spacecraft that is specifically designed to perform a specific task in space. The main function of a satellite is to provide communications, weather monitoring, and military surveillance from space. Because of their specialized role, satellites require a certain level of technology and precision to be built.
Satellites can range from the size of a small car to the size of a school bus, and they are built with varying levels of sophistication. Smaller satellites usually have just a few on-board devices whereas the heaviest satellites can have hundreds of on-board pieces of equipment. Sophisticated satellites can cost millions of dollars to build and launch.
Why Go To The Sun?
The sun is a natural choice for spacecraft propulsion, as it provides the needed energy to enable the spacecraft to travel to distant destinations. It is also the most accessible and the most abundant source of power in the solar system. It is bright and provides enough energy to power most spacecraft operations (excluding those that require nuclear reactions). The energy that is supplied by the sun is extremely valuable in space, so much so that it has been dubbed ‘fuel’ for lack of a more descriptive term.
Satellites travel to the sun under the auspices of one of the three primary space agency groups – NASA, ESA, or JAXA. These Agencies have established themselves as the primary spacefaring organizations for Earth orbit operations and have actively investigated, designed, and built solar-powered spacecraft technology that is currently in use. Much of this technology has been transferred to other groups and industries for implementation into other spacecraft.
How Does It Work?
When a spacecraft travels to the sun, its journey is a long and arduous one. It takes months to travel from Earth to the orbit of the sun, and even longer to reach the photosphere – the outer-most layer of the sun where most of the solar energy is generated. From there, the journey continues to the other planets in the solar system, with the speed varying based on the destination.
A solar sail is basically a big balloon that is propelled through space by the photons that are radiated out by the sun. It was first proposed in the 1950s and is still regarded as one of the more promising options for deep space travel. For a spacecraft to reach the speed of light, it will need to be propelled by extremely thin and transparent sails made of ultra-light materials (usually made of plastic). When sunlight is trapped by the sail, the vehicle is propelled forward due to solar pressure. Sails are a proven way to move large spacecraft, but they are not without their problems.
Even when designed to withstand the rigors of interplanetary travel, a solar sail faces an additional set of challenges when employed in space. Chief among these is the necessity to deploy the sail in a way that provides sufficient area to generate the necessary propulsion. Too often it is the case that a solar sail is designed to reach a goal velocity quickly, sacrificing the amount of area that is available for other functions such as communications or scientific exploration. Having a smaller sail area for the primary mission means that additional material has to be included for the secondary payloads.
The Evolution Of Satellites
The first generation of satellites were just small devices that were meant to take a few minutes to deploy and then perform a few specific tasks in space. These tasks included providing reconnaissance or communications for military or civilian use. Over the years, as technology has advanced and the complexity of missions increased, these tiny satellites have evolved into larger and more sophisticated devices that can now last years in orbit and carry out a variety of tasks.
The size of a satellite can range from a few hundred kilograms to many tons. The largest satellites are often just a cube shape to best take advantage of the sun’s energy. This also makes them easy to transport to orbit, as they do not require as much storage space as a fully equipped rover or lander. The smallest satellites are often just a few centimeters across, and weigh just a few grams. Some of the more recent discoveries have been made possible by the advent of nanotechnology, which has enabled scientists to design and build objects on a microscopic level. This has led to a number of revolutionary new products that are now available for use in space.
Going Further
With the exception of a select few large Agencies, interplanetary exploration is generally left to the private sector. This is in part due to the high cost of reaching other planets, as well as the time that it takes to make the journey. There are also several limitations that are often placed on these vehicles by governments due to security and/or economic concerns. The cost of a launch is often between several million and several billion dollars, and the cost of travel between the planets is exorbitant. Some of the more recent and innovative spacecraft designs that are available to the general public include;