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SpaceX launching communications satellite for NC-sized nation

Posted June 23

You get an appreciation for how large communications satellites when standing under them. The blue material absorbs energy during testing. (Credit: SSL)

This will be a busy weekend for SpaceX.

The company plans to launch BulgariaSat-1 from NASA’s Kennedy Space Center in Florida during a two-hour launch window which begins Friday, June 23 at 3:10 EDT.

Thirty-five minutes later, the satellite will be deployed into a Geostationary Transfer Orbit.

On the opposite coast, preparations are underway for the second of seven planned launches of Iridium’s next generation of communications satellite from the company’s SLC-4 pad at Vandenberg Air Force Base in California. Each launch will deploy 10 individual satellites. The launch window opens Sunday, June 25 at 1:24:59 p.m. local time.

This morning’s forecast predicts 90 percent probability of favorable weather for the Florida launch. The only concern reported by the Air Force’s 45th Weather Squadron is a possibility of cumulous clouds forming near the launch site, a very common item for forecasters to monitor this time of year.

A back-up launch window is available 24 hours later with 80 percent go probability. Cumulous clouds are not something you want to fly through, especially the tall ones. They are formed through updrafts of warm, moist air and are known to contain electrical fields which are hazardous for rockets. Even when no lightning is visible, the rocket itself can trigger lightning if launched in these conditions.

Friday’s planned launch of BulgariaSat-1 is notable for several reasons.

This is the second time a Falcon 9’s first stage will be reused. This booster previously launched the Iridium-1 mission from Vandenberg Air Force Base in January 2017. BulgariaSat-1 is also the first geostationary communications satellite the history of Bulgaria.

The satellite was built on Space Systems Loral’s SSL-1300 platform and carries a total of 33 Ku-band transponders with HDTV and Ultra HDTV broadcasting in mind. It will serve Direct-To-Home TV, corporate networks, and some very small aperture terminal (VSAT) communications (those small dishes you see on the top of gas stations and stores which are often used for credit card transactions and other low volume data).

I recently visited SSL’s Palo Alto, California headquarters, where the satellite was built. The company dates back to the late 1950's when it was as subsidiary of Ford. The 79-acre facility includes about 100,000 square feet of clean room and a pair of massive thermal vacuum chambers for simulating conditions in space.

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Antennae are tested in the Compact Antenna Test Range (CATR), an jaw-dropping room capable of simulating transmitting and receiving with a satellite 22,000 miles away. It was in that huge CATR facility I really got an appreciation for how big these satellites are, even without the city bus sized solar arrays.

Satellites are rarely designed and built from scratch and BulgariaSat-1 is no different. More than 100 satellites have been built on the SSL-1300 bus. Each spacecraft bus provides the basics like propulsion, attitude and thermal control, all built around a standardized structure that can be mounted atop a variety of rockets. First introduced in the mid-1980s, it has been incremental improved over the years. Change introduces risk in the space business and problems are difficult to solve once in orbit.

Modular design for efficient adaptation

Building on a proven spacecraft bus also reduces cost but for customers like BulgariaSat, the cost of the launch itself needed to come down.

In an address to the 2016 Asia-Pacific Satellite Communications Council Conference, SpaceX president Gwynne Shotwell said a 10 percent discount is being offered to customers who fly their payloads on a reused Falcon 9 first stage.

Maxim Zayakov, CEO of BulgariaSat told Spacefight Now that these efforts to reduce the cost access to space made the flight possible.

“For small countries and small companies like us, without SpaceX, there was no way we would ever be able to even think about space,” he said.

Think of it this way: North Carolina has about 3 million more in population than Bulgaria and the Raleigh-based Waste Industries is comparable in size and has nearly twice the value.


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