Aerojet Rocketdyne Puts the AR in Mars
June 15, 2018 - Getting to Mars takes propulsion systems of all shapes and sizes, but one thing they nearly all have in common is Aerojet Rocketdyne.
Beginning more than four decades ago with the Viking 1 and 2 orbiter/lander missions, NASA has relied on Aerojet Rocketdyne to propel its Mars missions – from launch, to landing and everything in between. These missions have ranged in scale from the 25-pound Mars Pathfinder rover, to the Mars Science Laboratory’s 1-ton Curiosity rover.
Curiosity, which touched down with the help of eight Aerojet Rocketdyne MR-80B monopropellant rocket engines in August 2012, continues to traverse the Martian surface courtesy of an Aerojet Rocketdyne-supplied nuclear power source for electricity and heat.
This interplanetary legacy continues with the recently launched Mars InSight lander that will land in November of 2018, and with the upcoming Mars 2020 rover. The latter features much of the same hardware, prominently including the Sky Crane landing system and nuclear-powered rover, as the Mars Science Laboratory. Aerojet Rocketdyne recently delivered the nuclear battery, or Multi Mission Radioisotope Thermoelectric Generator (MMRTG), for Mars 2020, which also will bring a small helicopter to explore the planet.
Mars Insight is still in a six-month journey that began May 5 with its launch from Vandenberg Air Force Base, California, aboard an Atlas V rocket, whose Centaur upper stage was powered by Aerojet Rocketdyne’s RL10 engine. The Centaur inserted Mars InSight into its initial parking orbit, and then fired a second time to send the lander on its way to Mars.
Ten days later, InSight’s cruise-phase thrusters – four MR-111C and four MR-106E engines generating 1 and 5 pounds of thrust, respectively – executed the first of two burns necessary to correct for the directional “offset” built into the mission’s launch trajectory. That offset is designed to ensure that the Centaur, which was not cleaned to the standards imposed on landers, does not ultimately crash into the Martian surface. The second offset correction burn that took place in July put InSight on a direct course to Mars.
The cruise-phase thrusters will perform four additional burns to fine tune InSight’s trajectory, the last coming just 22 hours before the probe enters the Martian atmosphere, where a different set of Aerojet Rocketdyne thrusters take over. Six pairs of MR-107 engines, each generating 50 pounds of thrust, will work in coordination with a parachute system to ease the craft down to the surface. Just prior to touchdown, the engines will move the lander laterally to keep it clear of the jettisoned parachute.
Aerojet Rocketdyne propulsion also figures prominently on Mars 2020, but delivering something of that size to the Red Planet requires a bit more kick. The Atlas V launcher, for example, will get additional lift from four Aerojet Rocketdyne AJ-60 solid-rocket strap-on boosters, each generating nearly 350,000 pounds of thrust.
The Mars 2020 landing scheme also is markedly different from that of Mars Insight.Like Curiosity, it will be lowered to the surface via cable from the Sky Crane, which will hover just above the Martian surface by the propulsive power of eight Aerojet Rocketdyne MR-80B engines, each generating up to roughly 750 pounds of thrust. Once the lander reaches the surface, the Mars 2020 spacecraft will use the throttle-able thrusters to fly away from the landing site.
Aerojet Rocketdyne’s Mars 2020 role doesn’t end there, however. Like Curiosity, the rover will be powered on the surface by the Aerojet Rocketdyne-supplied MMRTG, whose plutonium-238 fuel load will include a portion of the first batch of the isotope produced in the United States in 30 years.
One of the Mars 2020 rover’s objectives is to collect and cache Martian soil samples for return to Earth on a future mission that will execute what likely would be the first ever rocket liftoff from another planet. Aerojet Rocketdyne manufactured the ascent-stage engine for the only craft to lift off from another celestial body – the Lunar Excursion Module – and has performed design studies of a Mars ascent engine for sample return.
Aerojet Rocketdyne also is laying the groundwork for eventual human missions to Mars. The company is developing the solar electric propulsion system for NASA’s Lunar Gateway, work that will help pave the way for a larger system to deliver cargo in support of crewed missions to Mars, and has performed design work on a nuclear propulsion system that would dramatically reduce astronaut transit times to the red planet.
While human missions to Mars are many years away, Aerojet Rocketdyne is taking the necessary steps to be ready when the time comes. From the small robotic explorers of the relatively recent past, to the astronaut missions of the future, Aerojet Rocketdyne’s products are as integral to exploring Mars as its initials are to the spelling of the word.