InSight will lift off aboard the powerful Atlas V launch vehicle
On 5 May 2018, the InSight probe will be blasted towards Mars by the extremely powerful US launcher Atlas V, one of Ariane 5’s direct rivals. Atlas V is a two-stage vehicle: the first stage burns a mixture of kerosene and liquid oxygen, while the second—the Centaur upper stage—is powered by liquid oxygen and liquid hydrogen.
Given InSight’s relatively light weight, no strap-on boosters will be necessary. The Atlas V launch vehicle is so powerful that, unusually for a mission to Mars, it is planned to lift off not from Cape Canaveral in Florida, but from the Vandenberg Air Force Base in California.
Interplanetary spacecraft are generally launched from the Cape Canaveral Air Force Station to benefit from the sling effect due to Earth’s rotation, which is maximal at the equator. InSight will not need this helping hand, which is why the launch is scheduled from Vandenberg, a first in the history of Mars exploration.
The Atlas V 401 launcher version chosen has a 4-metre-diameter fairing under which InSight will be stowed.
An unusual feature of the launch, due to the room available under the fairing, is that the solar arrays for the cruise stage are to be installed in their final configuration, i.e. fully deployed. As they are not designed to be stowed in a folded position during the launch then deployed following separation of the probe from the launcher in space, they do not include any hinged mechanisms.
The launcher also carry two additional MarCO telecom nanosatellites. They will accompany InSight on its journey to Mars and relay telemetry data to Earth during the critical landing phase.