A few days back, we talked about a NASA-funded study that propounds a cheaper and more efficient approach, based primarily on public-private partnerships, to sending humans to the Moon, as early as 2035. With commercial companies joining today’s space race, researchers everywhere are looking for ways to make trips to space easier and less expensive. A similar attempt has been made by the scientists at Colorado-based firm, Escape Dynamics (ED). According to its recent press release, the company has successfully tested the prototype of an entirely new spaceship engine system that uses high-energy microwaves, beamed from the ground, to propel the shuttle into the stratosphere. If it indeed proves to be viable, the technology could one day cut the cost of sending a satellite into orbit, to a great extent.
At present, launch systems are mostly multi-stage chemical combustion rockets that use ginormous amounts of propellant to produce the thrust needed to launch into space. Apart from the high costs involved in the process, carrying several thousand pounds of explosives is in itself an onerous task. In the new research, the scientists have developed an innovative system that relies on microwaves, emitted from an on-ground thruster, to heat the hydrogen carried on the craft and subsequently, push the vehicle into space. Speaking about the project, Dr. Dmitriy Tseliakhovich, of Escape Dynamics, said:
We, for the first time, conclusively demonstrated that a new propulsion technology that goes beyond chemical rockets and that can be used for orbital launch works on a lab scale, and we are confident that we can take it to multi-megawatt scales and eventually introduce it into single-stage-to-orbit space planes that will change the way we reach orbit.
The new engine, on the other hand, does away with nearly all of the on-board power systems. In this case, high-energy microwaves, from a ground-based emitted or thruster, are transmitted wirelessly to a heat shield located at the spacecraft’s rear end, both during the time of ascent and the rest of its journey to outer space. The received power is used to drive a specially-designed electromagnetic motor, which will then ignite the hydrogen released from the tank. The necessary thrust is produced when the superhot hydrogen fuel is ejected from the ship’s nozzle. ED’s President, Laetitia Garriott, said:
With this technology, we can uniquely bring to market reusable, single-stage-to-orbit space planes, and aircraft-like operations to orbit, and significantly decrease the cost of access to space for payloads up to 200 kg.
Recent testing of the engine’s prototype showed a Specific Impulse (Isp), a standard of measurement of a rocket’s fuel efficiency, of more than 500 seconds while running on helium. According to the researchers, in comparison to chemical rockets that can attain a maximum isp of only 460 seconds, the new system can reach a Specific Impulse of up to 600 seconds, when using hydrogen. What is more, the company claims that it has designed a heat exchanger, which can absorb over 90-percent of the incident energy. Will Marshall, the head of Planet Labs, was reported saying:
Currently, small satellite payloads cost approx. $25,000-50,000 per kilo to launch, and must share a launcher with other satellites. I’m very supportive of efforts to create lower cost and more regular access to space. Escape Dynamics is pursuing a radical technology — one I fundamentally think is a good idea — which could massively reduce the costs for small satellite payloads.
The technology is still basically a concept, and will need to overcome several hurdles before it can become feasible. Some of the doubts, currently being raised, include the possible safety and environmental issues of releasing enormous amounts of microwaves into the atmosphere as well as the cost of building such a large network of space launch thrusters across the world.
Source: Escape Dynamics