Solar power has long been used to power electronics on board of spacecraft, in fact many of the first photovoltaic cells were used to provide satellites with energy in the 1960s. But now, more aerospace companies are looking at ways of propelling spacecraft with the sun as Aerojet Rocketdyne is doing.
Solar Electric Propulsion (SEP), according to Aerojet’s Executive Director for Space Programs Joe Cassady, is essential to the US’s future deep space planning. He recently testified before the Subcommittee on Space in the U.S. House of Representatives that "SEP is key to a sustainable architecture by enabling efficient transfer of cargo, habitats and payloads to deep space destinations in advance of astronaut arrival.” He added, “SEP systems are equivalent to cargo ships for deep space missions.”
While there’s no air in space to push off of, there are numerous ways to use solar power to propel a ship, like solar sails. Such sails capture the movement of photons through space and use that to push a craft through the vacuum, like a wind. Other methods use forms of electric propulsion powered by solar radiation. Already NASA is investigating at least four types of SEP.
"As NASA looks to expand human presence in the solar system, starting with missions to lunar orbit and onto Mars, development of efficient in-space transportation systems is critical," Cassady said, in explaining why research funding is imperative. "We are well on our way to having efficient in-space transportation with SEP. We must continue to adequately fund these development efforts to ensure that we will have the first human footprints on Mars in the 2030s."
Another advantage SEPs have is that they don’t necessarily require an additional chemical propellant. As such, Aerojet said SEP systems are between 6 and 10 times more efficient as a propellant than traditional chemical propulsion systems. It added that already more than 200 commercial, civil, national security and defense spacecraft are using SEP for stationkeeping, repositioning and orbit-raising.
Aerojet said that SEP will be able to transport approximately 75 percent of the mass required for human missions to Mars, reducing the amount of launches required to set up a base for human habitation.
"Heavy equipment, supplies, and other logistical items are pre-deployed by large cargo ships and planes to the region. Then, once the equipment, barracks, etcetera are ready, the troops follow by faster air transport,” Cassady said.
The company developing three high-power electric propulsion systems for NASA. The NEXT-C xenon ion engine will support planetary missions. The Advanced Electric Propulsion System (AEPS) will support deep space cargo missions and NASA's NextSTEP 100kW Nested Hall Thruster will support future technology insertion, according to Aerojet.Tweet