The search for life on Mars | Natural History Museum


Is there life on Mars? Has there ever been? These questions have inspired science and
science fiction alike. But a mission, led by the European and Russian
Space Agencies, might finally reveal what really lies beneath the surface of the Red
Planet. We’ve been sending missions to Mars since
the 1960s to find out what, if anything, could survive there. In 1976, the Viking 1 lander made history
as the first space craft to successfully land on another planet. Twenty years later, Mars Pathfinder was better
able to explore the surface, as the first mission to use a rover alongside a lander. More recently, the twin rovers – Spirit and
Opportunity – have proved that the surface may once have been covered in oceans and lakes. And, in 2018, the Curiosity rover found evidence
of organic molecules – the raw building blocks for life. However, no signs of life have yet been confirmed. But an upcoming mission could change that. This is the ExoMars rover. It will be the most advanced rover sent to
Mars. It’s being developed just north of London
by Airbus in a purpose-built Mars Yard. The Mars Yard is a simulated Martian environment.
It has the right sands and rock types that we expect to encounter on Mars, which we then
use to develop our prototype rovers. We’re very much in the Age of the Rover. We
don’t really now where on Mars is most interesting to take samples and look for signs of life,
so we want to use rovers rather than landers to cover as much distance as we can and try
lots of different scientific sites. We design a rover to be able to drive long
distances on Mars. There are two main challenges that we have
to design around. The first of these is the thermal environment – the temperature range
on Mars can go between ten degrees in the day to -130 degrees at night.The electronics
that sit inside our rover and control everything, they don’t like it at the very low temperatures
and we have to design an environment on board that isolates the electronics from these extremes
of temperature. The second is dust, particularly for a solar
powered mission like ours. Dust storms on Mars tend to be peaking around the Martian
winter and so the simple way to design the mission around them is to land just after
the Martian winter in the Martian springtime. They will be something we’ll have to deal
with eventually but the idea is that we’ve achieved all our scientific goals by then. The navigation of the rover and the way it’s
able to move around is actually really important because the time delay between Earth and Mars
can be as bad as twenty minutes. So it’s either really inefficient to drive
it by remote control or it’s actually dangerous. So instead we’ve designed our rover to be
as autonomous as we possibly can to the point where all it needs is the target we want it
to reach. We tell it nothing about the terrain, we tell it nothing about the best route to
take. Everything else is done on board. The navigation cameras at the top of the mast,
they see in 3D and that allows the rover to determine where the rocks and the slopes are
in front of it. If any of those rocks are too big or the slope is too steep, that area
will be marked as forbidden and the rover will not go anywhere near it. There’s also quite an interesting feature
in the locomotion system called trajectory control. If we start to get disturbed from
the path we’re trying to follow, because of the nature of the terrain, the system realises
that is happening and will bring us back on to the path we’re trying to follow. That’s
more efficient but it’s also safer for the rover as well. We have a really flexible locomotion system
in that we can actually steer and drive all six wheels at the same time. this allows us
to follow a curve, crab sideways, spin on the spot, and we can actually do a combination
of these geometries to achieve different effects whilst we’re driving. That’s something no
other rover has been able to do to date. To know where to go, the rover will need a
pair of eyes. Luckily, the Mullard Space Science Laboratory is up to the challenge. We’re working on the ExoMars PanCam, the panoramic
camera system. So this is the scientific eyes of the rover. This will actually be able to
do some geology and some atmospheric science. It uses a combination of cameras to be able
to do that. Yes, so this the PanCam optical bench. So
that’s the thing that houses all the camera systems. So it has two apertures here. Each
of those for the two wide angle cameras, and this is the high resolution camera aperture.
And so PanCam is inside this optical bench and the real thing is sealed on Mars. The rover is going to be drilling underneath
the surface of Mars for the first time to look for signs of life, but to do that you’ve
got to decide where to drill. So we have context instruments. So PanCam is the most important
of those, but there are several others. As well as PanCam there’s the infrared spectrometer,
there’s a close-up imager, there’s a sub-surface sounding radar, there’ s neutron detector
and there is also a little camera inside the drill tip. The ExoMars rover will be the first mission
to drill deep down into the Martian surface. It will drill two metres down, to where scientists
believe there may be a layer of permafrost. This is where they’ll look for evidence of
life in the past or even life today. What we do is get the sample from underneath
the surface, bring it up to the rover and put it inside what’s called the analytical
drawer. And then there are three more instruments inside of there which will analyse the sample.
So that combination; the context instruments tell you where to drill, then once you’ve
drilled we look at analysing the sample. We’re not expecting to find things like dinosaur
bones, for example. Potentially going to be things like traces of fossilised bacteria. All the instruments, robotics and computing
power mean nothing if the rover doesn’t land in the right place. So experts at the Natural
History Museum have joined an international effort to figure it out. Choosing where to land on Mars is actually
quite a challenge because we want to land on the really old parts of Mars where we think
we stand the best chance of finding traces of past life, but these regions also tend
to be pretty high so there’s less atmosphere to slow a rover down as we descent towards
the surface of Mars. So it’s really about finding a balance between
somewhere that’s relatively low and somewhere that’s relatively old. So we’re landing in this region North West
Arabia Terra, here, because it’s actually quite near the hemispheric divide on Mars
where the southern highlands – the old part of Mars – borders the northern lowlands – the
young part of Mars. So this region here has the advantage of being relatively low down,
so there’s enough atmosphere, but is also relatively old. Margin for error in where we’re actually going
to land, it’s about 100 kilometres or so, so we need to be very very sure that the entire
area across these two sites, across the entire landing area is safe for the rover to land
and safe for it to explore, but also that there’s going to be good science to do wherever
we land within the sites. The thing I’m most worried about, I guess,
is the landing. The time delay is as much as seven minutes at that point. It tends to
get referred to as the seven minutes of terror. And thus the landing system has to be able
to land the rover safely all without any interaction from Earth. Earth will only find out if it’s
landed seven minutes after it either has or hasn’t, on the surface, so that will be quite
a nervous time. The landing sites are selected in sort-of
a balancing act to make sure that the rover can deal with the environment that will encounter
once it lands on Mars. Inevitably most of the scientifically interesting sites are the
hardest to get to. The two sites where the rover could potentially
land are called Mawrth Vallis and Oxia Planum. Both sites are covered in clay minerals. Clay
minerals are important because we think they form in water on the Earth, so we think that
four billion years ago these clay minerals at the two sites formed somehow in liquid
water and we think they would potentially be good at preserving signs of life, so organics. To help inform the ExoMars mission, scientists
have been working with some pieces of Mars that we have right here, on Earth. So the Museum has one of the best collections
of Martian meteorites in the world because it’s quite a diverse collection. The cream
of the meteorite collection for Martian meteorites is this one here called Nakhla, which fell
about 100 years ago, in Egypt. In the 1980s, researchers at the Museum found
that it actually contained traces of water and this was the first evidence that the planet
Mars actually has water on it. It’s one thing to find water on Mars, but
life? One of the really big questions is whether
there’s life on Mars because once we did think it was much warmer and wetter and so it might
have been habitable. In 1996 a group of researchers published evidence for fossilised bacterial-type
life, they found these little fossil morphologies in a meteorite called Allan Hills 84001. And
we now think these little wormy things they found were probably not fossilised Martian
life but it’s really invigorated the debate. And absolutely one day we might find that
evidence that we’ve been looking for, that there was life on Mars. Other rovers started off looking for water
and following the water, now looking at habitability, but we’re going right to the heart of the
question of ‘was there life there?’ My feeling is that Mars was formed around
the same time as the Earth in a similar part of the Solar System, where water can exist
as a liquid. And if our assumptions about what life needs are correct then in theory
we should find it next door. It think it’ll be bacterial level of life, it’s the most
hardy form of life we have on Earth, so if we do find it it’ll be that. But I’m fairly confident we will
find what we’re looking for, yes. Mars probably had the conditions for life
four billion years ago, so whether or not life evolved there is an interesting question.
Two planets within a solar system both hosting life is quite a good sign for perhaps life
elsewhere in the universe. Ultimately, that’s what’s most exciting about
the ExoMars mission. If we find life on Mars, there’s no limit
to where else in the universe life has found a way. We hope you enjoyed that video. Don’t forget
to share it and subscribe to our Youtube channel. You’ll also find loads more amazing content
on the space hub on our website.

Leave a Reply

Your email address will not be published. Required fields are marked *