Recently, Boeing announced the first ever communications satellite to use no chemical propulsion at all, which has profound implications for the future of space. The $400 million deal just signed with Asia Broadcast Satellite (ABS) and Satelites Mexicanos (SatMex) to build the first all-electric commercial telecommunications spacecraft to be sent into orbit has taken aback even the most dubious critics.
This technology implements lightweight xenon-fueled thrusters rather than chemical propulsion in order to maneuver a spacecraft platform into position.
The switch from chemical rockets to ion thrusters comes with benefits and drawbacks. First, traditional chemical rockets provide much more power, allowing quick acceleration. However, the cost of propellent is extraordinarily high because more propellant must be expelled to achieve a given change. This is exactly why ion propulsion has excited many spacecraft designers and engineers.
“We think this might expand the market quite a bit,” says President of Boeing Satellite Systems International Steve O’Neill in an interview with Aviation Week. O’Neill has spent the past five months negotiating the deal for Boeing. “The total cost to market will be significantly different for a satellite operator than it is currently.”
Ion propulsion works by stripping or adding to the electrons in a noble gas in order to get an electrical charge. Then, the ion engine will accelerate the electrons with either an electric or magnetic field, subsequently shooting them out the back end of the thruster.
This process can provide exceedingly high exhaust velocities greater than chemical propulsion by a factor of 10, meaning the spacecraft would need only a fraction of the propellent used in a traditional chemical rocket. Thus, this technology can cut the satellites weight in half and as a result, the launch costs. Depending on the size of the spacecraft, savings are estimated at $100 million.
Besides reducing weight, all-electric spacecraft offer the opportunity to add payload capacity and boost performance.
“The more you use electrical propulsion, the lighter the spacecraft becomes and the more payload you can put on it,” Simpson said in an interview with Aviation Week, adding that the ion-propulsion satellites can accommodate 47 active transponders and generate 3-8 kw of power. “You’re getting quite a significant value proposition, up to 7.5-8 kilowatts of capacity, but it’s much more economical from a launch perspective.”
However, there are some downsides. For instance, an ion system has a very low thrust. Whereas chemical rockets can provide their own energy in the propellent, an electrical system’s propellent has no energy of its own, therefore it has to be provided externally which limits its thrust to the power available. However, one could remedy this problem by implementing a nuclear reactor which would certainly be effective which could supply ample power; albeit the cost and politics of such an endeavor prohibit the use of this power source.
Using ion thrusters is not going to be easy, for it will take Boeing’s satellite months to attain the operating altitude which initially will reduce the return on investment. This is because the travel time through the highly radioactive Van Allen belts will require additional shielding to last the arduous journey.
Looking into the future, this same technology could drastically reduce the costs of trips to the moon and beyond by not only reducing weight, but adding payload and therefore boosting performance. Not to mention, ion propulsion is meant to carry large payloads.
“The more you use electrical propulsion, the lighter the spacecraft becomes and the more payload you can put on it,” said vice president of business development at Boeing Space and Intelligence Systems Jim Simpson in an interview with Aviation Week, adding that the ion-propulsion satellites can accommodate 47 active transponders and generate 3-8 kw of power. “You’re getting quite a significant value proposition, up to 7.5-8 kilowatts of capacity, but it’s much more economical from a launch perspective.”
Put simply, this satellite will have have better bandwidth and subsequently more channels due to the increased power on board. Having more channels to broadcast in means increased revenue for Asia Broadcast Satellite (ABS) and Satelites Mexicanos (SatMex).