United Launch Alliance

United Launch Alliance

United Launch Alliance

United Launch Alliance

United Launch Alliance

United Launch Alliance



United Launch Alliance

United Launch Alliance

United Launch Alliance

United Launch Alliance

United Launch Alliance

United Launch Alliance

United Launch Alliance

After the space shuttle retired in 2011, the Delta IV Heavy became, by default, the world's most powerful rocket. Standing 71.6 meters tall, fully 15 meters taller than the full space shuttle stack, the rocket built by United Launch Alliance can deliver up to 28.4 tons of mass to low-Earth orbit.

On Saturday, under splendid blue-and-white Florida skies, the rocket made one of its rare launches by delivering a spy satellite payload, NROL-37, for the National Reconnaissance Office into orbit. The agency has released no information about the satellite, but from the Delta IV Heavy's use we can conclude that it likely was one of the spy office's Advanced Orion satellites, which measure radio signals from the vantage point of geostationary orbit.

The Delta IV Heavy rocket has not flown since December, 2014, when it launched NASA's Orion spacecraft into a two-orbit test flight around Earth, reaching a peak altitude of 5,800km. In its entire history since 2004, the rocket, which uses three common booster cores to power its ascent, has flown only nine times. One of the reasons the Delta IV flies so infrequently is its cost—up to about $400 million per flight.

But so far cost has bought the US defense industry reliability. United Launch Alliance, a joint venture between Boeing and Lockheed Martin, has an enviable record of 107 successful missions out of 107 launches with the Delta IV and Atlas V lines of rockets, which trace their heritage to the 1960s.

Nevertheless, in recent years the company has come under pressure both because of high costs and geopolitical tensions. United Launch Alliance flies its lighter-duty Atlas V rocket most frequently, at a per flight cost of about $200 million after factoring in $800 million "capability contract," which the company receives from the US military to maintain launch readiness. By contrast, SpaceX offers its comparable Falcon 9 rocket at a price of about $60 million per launch. In addition, Congress has pressed United Launch Alliance to develop a new variant of the Atlas V which does not rely on Russian-made RD-180 engines. The company has responded with the development of the Vulcan rocket, which likely will use engines manufactured by US-based Blue Origin.

The Delta IV Heavy may only remain the world's most powerful rocket for a matter of months. Although it has been often delayed, the Falcon Heavy rocket being developed by SpaceX is likely to fly later this year or early next. Like the Delta IV, the heavy Falcon rocket has three booster cores. However, instead of being powered by a single RS-68 engine, each of the Falcon cores is powered by nine Merlin engines, making for a total of 27 engines firing at liftoff. That makes for a complicated rocket, but if SpaceX can pull it off, it will offer customers the capability to deliver up to 54 tons to low-Earth orbit at a cost of $90 million. Therefore, while the Delta IV comes in at $14 million per ton to orbit, SpaceX might offer customers a similar heavy lift service at $1.7 million per ton.

It's not clear how much longer the Delta IV Heavy will fly—and therefore each launch should be savored by rocket enthusiasts. We did just that this weekend.

Listing image by United Launch Alliance