SpaceX Falcon 9 to carry two Boeing all-electric satellites into orbit tonight

If all goes according to plan, private spacecraft will take another major step forward tonight. While it’s a SpaceX Falcon 9 rocket that will carry the payload, this time it is Boeing’s turn to make a little history.

Tonight’s launch, scheduled for liftoff from Cape Canaveral at 10:50 EST tonight, will carry two all-electric communication satellites into orbit.

All spacecraft, including satellites, need some form of propulsion. Satellites in orbit achieve most of their movement through gravity, however they still need propulsion systems to get into orbit and to make periodic corrections to their orbit once they are in place.

The problem is that sending stuff to space is expensive and traditional, fuel tank propulsion systems are heavy. According to NASA, the approximate cost of launching something into space is $10,000 per pound and the fuel tanks for a satellite propulsion system can weigh up to 5,000 pounds. That’s about 50 million dollars for a satellite’s propulsion system alone.

By switching to electrical, ion engines the Boeing 702SP is able to build extra communications capacities into the satellite, while still reducing the overall weight of the spacecraft by as much as half.

“One of the big drivers was cost. We’re able to get the launch cost significantly reduced, get more payload mass to orbit, and reduce the overall cycle time of (building each satellite),” said Mark Spiwak, president of Boeing Satellite Systems International Inc., to Spaceflight Now.

Boeing, in fact, has reduced the weight of the satellites so much that tonight’s launch will carry two satellites into orbit. A SpaceX Falcon 9 would normally only be able to carry one.

“The real driver for that lighter solution was to be able to stack two commercial communications satellites on top of each other and provide a dual launch. When you look at the mass of a satellite, with kind of a classic satellite system, it’s dominated by the fuel load of the direct-to-orbit mission. Going to an all-electric system, you’re able to reduce the fuel load by almost a factor of 10. That fuel load reduction allowed us to stack the satellites on top of each other, and give the customers a two-for-one deal on the launch costs,” said Mike Connelly, director of Boeing’s product line for the new 702SP platform.

The owners of the satellites, Eutelsat and ABS, each paid less than $30 million to launch their satellites. Which is “almost unheard of” according to satellite industry veteran Ken Betaharon, chief technology officer at ABS.

Unfortunately, the combined satellites are a little too heavy and need to be carried a little too high for SpaceX to attempt to land on SpaceX’s recovery barge. It has been a longstanding goal of SpaceX to further reduce the cost of launches by creating a re-useable stage one rocket and landing it on a floating robotic platform at sea.

However, with two more launches scheduled before mid-April, Elon Musk’s private space firm will have more opportunities to make the attempt soon.

The trade off for switching to the lighter propulsion system is that it will take longer for the satellites to get into position.

“The advantage you get with xenon-ion is very high ISP (specific impulse, or efficiency), but the consequence is that the thrust is low and it takes longer to get from the transfer orbit to geosynchronous orbit. The basic science of the transfer orbit doesn’t change, it’s just the amount of time to get through the orbit-raising period,” said Connelly.

If all goes well, the satellites should reach their final position in orbit and be operational in late August or early September and will remain operational for about 22 years.

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