Posted: Thu, Mar 19, 2015, 11:40 AM ET (1540 GMT)
NASA announced Wednesday that it has selected a Delta 4 Heavy to launch a solar probe mission in 2018. NASA said it awarded a $389-million contract to United Launch Alliance for the launch of the agency's Solar Probe Plus mission, scheduled for July 31, 2018, at the beginning of a one-month launch window. ULA will launch the spacecraft on its Delta 4 Heavy, the largest launch vehicle currently available, with a Star-48 upper stage provided by Orbital ATK. NASA had previously considered using the most powerful Atlas 5 version, the Atlas 5 551, but determined that vehicle would require the use of a new, custom-developed upper stage. Solar Probe Plus will be the first spacecraft to fly through the solar corona, approaching within four million kilometers of the solar photosphere; the powerful launch vehicle, along with multiple gravity assist flybys of Venus, are needed to bring the spacecraft that close to the Sun.
