Castrol products have been lubricating cars and engines on Earth for decades. A lesser known fact is that they have also greased the mechanisms on NASA space projects since the 1960s. On its quest to explore the solar system, NASA has turned to Castrol’s Braycote range for use on the Apollo moon missions, the Hubble space telescope, numerous satellites, the International Space Station, previous Mars rovers – including Curiosity that touched down in 2012 – and the majority of astronaut spacesuits.
Now, NASA is once again relying on Castrol to support its latest mission to the red planet. The Mars InSight lander blasted off from California on 5 May and began its 301 million-mile (or 485 million-kilometre) journey to its landing site on a non-descript lava plain on the Martian equator, called Elysium Planitia. When the lander safely touches down at its destination in late November, Castrol products will keep the scientific instruments moving as they should in an environment where any technical failures can mean mission aborted.
Weaker gravity, temperature extremes and the inability for humans to simply ‘go fix’ a faulty part all make Mars a hostile environment for a lubricant, to say the least. Each Castrol product has to suit the application, the environment and the duration of the task in question. And for NASA missions, Castrol’s products have to be especially hardy.
Keith Campbell, a business development manager at Castrol, knows a thing or two about the challenges that space poses for lubricant manufacturers, since he has worked with NASA on some of their missions. “It’s not like you can take in the equipment and do maintenance,” Campbell says, “so NASA wants to use a lubricant that they know is going to work.”
Whenever metal parts rub against one another, they create wear – and that can cause components to degrade and eventually stop working altogether. The remoteness of Mars means durability is key when it comes to selecting a lubricant for a mission.
The wild temperature swings on Mars also pose complications; Castrol’s lubricants need to operate at extremes. Crucially, the lubricants need to limit ‘outgassing’ – or giving off vapours – as temperatures change. Vapours can result in the loss of all the oil in the lubricant which means reduced performance, and condensation forming on nearby surfaces resulting in the possible contamination of sensitive instruments or the surrounding environment.
Mars InSight is the first mission to leave from Vandenberg Air Force Base in California. Most space missions travel from NASA’s Kennedy Space Centre in Florida and fly east. That's because launching towards the east adds the momentum of Earth's eastward rotation to the launch vehicle's own thrust. But, InSight’s rocket is strong enough to travel south from California – and the Vandenberg base had more availability for the launch window this year.
Campbell compares the ‘outgassing’ process to being, “a bit like a tin of paint drying out if the lid isn’t closed properly. The same thing can happen in space as it is a vacuum”. If outgassing happens in space, lubricants can dry out and not do their job as efficiently.
“We define a good lubricant in space by its ability to work at very, very cold temperatures and its ability to also work in warmer conditions - and to produce minimal outgas at warmer temperatures,” Campbell says.
But the challenges posed by operating in space don’t stop at managing temperature fluctuates. The lubricants have to be non-reactive when they come into contact with rocket propellants, gases and other chemicals, Campbell says. These lubricants cannot degrade at all when faced with the harsh elements of space.
“With our products, we have the best combination of low temperature performance and low outgassing,” Campbell says. “And that’s what gives us a competitive advantage.”
The Mars Insight lander is equipped with state-of-the-art scientific equipment to carry out its research. The lander is full of devices with moving parts, including bearings, linear slides and gears. Castrol products will keep these components operating in Mars’s harsh environment.
InSight’s seismometer, SEIS (or the Seismic Experiment for Interior Structure), is a mushroom-shaped instrument that sits on the planet’s surface. It is designed to take the ‘pulse’ of Mars, measuring seismic vibrations, from marsquakes to meteorite strikes. The purpose is to gain insight into what’s happening beneath the surface. SEIS is also equipped with sensors to measure wind, pressure, temperature and magnetic fields. NASA hopes to use measurements from SEIS to learn about the material that first formed the rocky planets of the solar system. SEIS might even find out if there is liquid water there.
The Heat Flow and Physical Properties Probe, or HP3, is a ‘mole’ that will tunnel down to five metres (16 feet) below the surface. It’s going to bury deeper into Mars than any previous device to measure the heat coming from the planet’s centre and how much of that heat flows to its outer layers. The measurements will help NASA determine if Mars was formed from the same material as Earth and the Moon – and may lead to insights into how the planet itself was formed.
The lander doesn’t have a crew to heave its equipment onto Mars’s surface. So InSight will use its Instrument Deployment Arm to offload SEIS and the mole. At 2.4 metres (7.8 feet), the arm has four motors to articulate joints on the shoulder, elbow and wrist. An arm-mounted camera will help NASA scientists see what they are doing. The arm also comes complete with a grapple with five mechanical fingers for grasping each piece of hardware.
Castrol has been used on previous Mars missions. In fact, one rover – Mars Opportunity – is still roaming the planet after 14 years. It was only designed for a mission lasting 90 days but it has now travelled further than any other manmade object on a surface besides Earth