Delta Heavy IV was a variant of Delta IV line, and until recently, it is considered as the most powerful operational launching vehicle in the world when it comes to launching mass. While most of the work of Delta Heavy IV is dedicated for the market of defense, it is also highly regarded in space circle for having a successful launch of the Orion spacecraft on its test flight last December 2014. For the current year, Delta Heavy IV will also be launching Parker Solar Probe.
The rocket line of the Delta IV is constructed by McDonnell-Douglas, who later become a part of the Boeing), and is currently manufactured by the United Launch Alliance. Delta IV possess multiple variants, which include the three Delta IV Medium Plus and the Delta IV Medium variants.
The Delta IV Medium has not flown since 2006 and in 2015, the United Launch Alliance elaborate that it will retire all of Delta IV Medium Plus configurations in the present year or the next because of the increase in cost in the launching system, according to the Spaceflight Insider. On the other hand, the Delta IV Heavy is anticipated to still be in the service until 2020.
Regarding military market, the Delta IV Heavy’s future would probably change since Falcon Heavy can loft the heavy satellites at a lower cost. Last February, there is a report in Ars Technical that Falcon Heavy rocket is only costing $90 million in every launch, whereas it is quite affordable compared to the $350 million per launch offered by the Delta Heavy. With that price, it makes Delta Heavy as four times as expensive as the Falcon Heavy, depending on the idea of how the costs are being calculated.
Currently, the government has the exclusive contract with the ULA, which is expected to come out next year for the Atlas rockets and in 2020 for the Delta rockets. The mentioned $350 million are not including the value of the contract since it is valuing $1 billion every year.
While the per launching cost of Delta Heavy is quite higher compared to Falcon Heavy, the rockets have their perfect record ever since they made their initial partial launching failure in 2004. Falcon Heavy has one test flights but is anticipated to lift off twice more this year. Both reliability and cost will come under consideration as the government of the US is considering its options for renewal of the contract.