The UAE plans its first Arab spaceship to Mars in 7 years. What’s more, they plan to land it on Mars. With this, they are aiming high indeed, as Mars is probably the most difficult place to land a spacecraft in the inner solar system.
I have no idea what their plans are, but it could be a wonderful opportunity to do something truly astonishing – and fly some of the innovative light weight Mars craft that have been developed over the years.
Perhaps these ideas are too innovative for NASA or the ESA or Russia to contemplate at present? At any rate they have never flown. But they might be ideal for new countries with less history in space exploration, and willing and interested enough to try something different.
So first, why is a landing on Mars is so difficult? The problem is the Mars atmosphere.
It is too thin to use for a soft landing with a parachute. So on Mars you can’t do this
Apollo 15 – it can sometimes be tricky landing on Earth also. It had a malfunction so that only two of the parachutes worked, landing on the Earth. Two of the shrouds of the third parachute probably destroyed by a fuel dump during re-entry. Return of Apollo 15 to Earth
Then parachute – but is not possible to parachute all the way to the surface in the near vacuum.
Finally, rocket motors for the last few tens of meters, to slow to a standstill.
- first aerobraking with a heat shield.
- Then discard the heat shield, continue on parachute.
- Then discard parachute because it can’t take you all the way to the surface.
- Finally land using rocket engines. The rockets have to cut off at just the right moment when the spacecraft is only a few meters above the ground.
For this final stage another alternative is to use airbags.
- Has to land on a level surface. If it hits a large boulder and topples over – then for most spacecraft designs, then that’s the end of the mission.
It’s obviously harder than landing on Earth.
HARDER THAN LANDING ON THE MOON
But it’s also harder than landing on the Moon too. On the Moon, though you have no parachutes, you can go into a very low orbit, a few kms above the surface – which you can’t do on Mars.
And with the low gravity – you can basically “hover” above the surface – and because there is no atmosphere also – then if worst comes to the worst you can abort and fly back into orbit, if you have enough fuel reserve, and try again.
The Mars atmosphere varies in density – and with dust storms sometimes covering the entire planet – often at the times that spacecraft arrive at the planet – and is generally hard to predict.
Combine that with the need for a complex landing sequence, and – also everything has to be totally autonomous. By the time the lander arrives on the surface of Mars – that’s within a few minutes of entry into the atmosphere. It takes a minimum of eight minutes to send the information about its entry to Earth and for us to send a signal back. So even if you spotted a major malfunction during the entry sequence – and respond instantly within seconds – it is no good – the whole thing is over by the time your instruction reaches Mars.
LANDING ELLIPSE UNCERTAINTY
Also – because of the winds on Mars – and the atmosphere – you have the uncertainty that you can’t do a pinpoint landing as you can on the Moon. On the Moon – they could land within meters probably of the desired landing site.
Most landing ellipses for Mars can’t fit into the Gale crater where Curiosity landed.
The ExoMars 2018 Landing Site is 104 km by 19 km – this image shows it on a possible landing site:
Chances are their landing ellipse will be similar or larger. So – they would need to find a large flat area of Mars to land on. And it’s almost impossible to find such an area with no boulders at all – so there will be an element of chance involved.
It might be a better method than rockets, less to go wrong, but Beagle II tried this same method and failed
Beagle 2 highlighted a major issue, that – they didn’t have live telemetry from the surface. So nobody knows why they failed, turned up a list of several different possibilities.
They would be well advised to have lots of telemetry. And expect the first landing to fail, but learn from that and go on to the next one.
In some cases the reason for the failure is known. For instance Mars polar lander failed because its engines cut off early – because of a software programming error that “detected” the surface before it got to it.
KNOWLEDGE OF MARS SURFACE
On the plus side we do have very detailed images of the Mars surface, now, down to a resolution of meters.
That’s a major plus over some of the earliest Mars missions, but we still have the uncertainty of the atmosphere, huge landing ellipse, need for total autonomy – and this complex landing sequence where every stage has to work on time, first time.
You can’t do it step by step, accomplish one step, and then more on to the next after communications with Earth – as you can on the Moon (say).
They could try this idea – make the light weight construction into an asset.
NASA’s Space Place. See also Inflatable Robotics
This is another fun and innovative idea, which again need not be particularly heavy.
With really small light rovers, then the landing would be simpler.
Here the idea is to use solar powered balloon rovers which don’t land at all – so missing out one of the most dangerous steps in the landing sequence.
This is project Archimedes – a 2009 mission by the German Mars society which never flew.
Or they could try the Solar Montgolfiere Balloons for Mars
MICRO GLIDERS ON MARS
This is an idea that’s been suggested, but not actually tried. It has the advantage again – that though you do get there eventually, you don’t land on Mars right away.
You have a long flight down to the surface. In some of the ideas – it is a single flight to a crash landing on Mars, and that’s it – still worth doing with images sent back all the way.
But in others (I don’t think this is widely known) – then you can land at the end of your flight, and can take off again. So – if it fails – you have all the images from the first flight down.
When starting a new indigenous Mars spaceflight program, perhaps they might like to try this.
Advantage is – inspiring new technology and ideas. if it works – could send lots of gliders to explore areas of Mars close up.
NASA’s Langley Research Center Artist’s concept of the Mars Airplane – one of many ideas – this is a tiny plane with five foot wingspan which folds to fit into an aeroshell for entry into the Mars atmosphere.
With one of these planes they found a way to put it into a stall at a 70° angle towards the ground, They found that in this configuration, it falls reasonably slowly, rather like a parachute. The plan was to add thrusters for a vertical soft landing on the Martian surface.
After a vertical tail first landing like this, your airplane could take off again, using the same thrusters. This is a plane that could land on the surface of Mars and then fly again repeatedly. Essentially, it’s a design for a miniaturized Mars version of VTOL flight.
In the early days of the space shuttle, the plan was to fly a space shuttle every week. One of the things they could do with all those launches is to send lots of airplanes to Mars for close up exploration of the surface.
Wild idea – feather light model planes with low take-off speeds for the thin atmosphere of Mars
This is not a worked out study but just an idea I came up with a friend. But might suggest some interesting approaches to explore.
Again – it is an idea for really light machines, easy to send in a small package to Mars, so seems relevant here.
Even the tiny mini Mars gliders of NASA are still robustly built, not exactly featherweight.
I was talking to Billy Stiltner, he flies model planes able to fly slowly, slowly, almost float through the air like thistledown.
In case you haven’t seen this before, you can find videos of these featherlight planes on youtube
He said he doesn’t think that there is a minimum airflight speed for an aircraft, if you can make it of light weight enough materials.
So even though it is usually said a plane needs to be fast to fly on Mars, perhaps that’s because they design them around the idea of a heavy plane with a heavy payload. You don’t need strong materials, since the atmosphere is so thin. Especially if you avoid flight during the dust storms.
Even during the strongest winds on Mars, they are fast winds in a near vacuum, in a thin atmosphere corresponding to 30 or 40 km up in the Earth’s atmosphere.
Our rovers have never had any problems with wind damage (the only wind related problems are to do with dust spread by the winds when they cover the solar panels). They have many delicate appendages (cameras, solar panels etc).
So we wondered about the idea, could you have an aircraft made of light materials which would be flimsy on Earth, yet are robust enough for the thin atmosphere of Mars? It could fly slowly – at least = obviously not as slowly as in the thick atmosphere of the Earth, but a lot slower than any of the other ideas.
These would be planes with almost transparent wings of mylar and the like, and their structures could be built of reasonably strong ultralightweight materials such as aerographite. They would be featherlight, but strong enough for Mars.
We came up with the idea – on Mars, what if you hang your planes from a tall pole, on a line short enough so they don’t hit the ground, and set them flying around.
You could probably set the thing 100 meters into the atmosphere or more and with the thin atmosphere, there isn’t much chance of it blowing over.
If necessarily you can add guy-lines to stabilize the pole. This would be especially useful if you want to carry your planes and the launching pole on a smaller mission or rover. A tiny rover like pathfinder could peg in the guys or loop them over or around boulders.
Once it is all set up, you set the planes flying round and round like the round the pole flying for model aircraft. This simulates an enormously long runway on the surface of Mars.
Eventually they fly fast enough to reach their take off velocity. Then they release their leads and fly off on their missions.
When they come back again after their flights, you set the guys spinning fast around the pole, until they reach the flight speed of the airplanes. The planes then dock onto the hooks at the end of the leads. With modern technology – it shouldn’t be too hard to find a way for the planes to dock with the leads when they come back again.
Then the plane flies round and round the pole, as it gradually slows down, ike landing on an enormously long runway – and then when it “lands” it goes into a box on the rover, or some kind of shelter for the planes in the dust storms.
If it has a shelter, it only needs to fly in good weather on Mars, permitting yet lighter construction.
Since the planes are so light, and especially if the camera and transmitter can also be miniaturized and light as well, you might be able to have dozens of them stored on a single rover. They could be designed to fold up when not in use, andvfor transport to Mars. Or they could b be designed to stack on top of each other for compact storage (or both).
That is just a back of the envelope type idea, maybe someone would be interested in exploring it a bit further.
As far as I know it is an innovative idea, never heard of any study of the idea of either round the pole flying on Mars as a way to launch aircraft – or the idea of featherlight thistledown light aircraft on Mars.
ENTOMOPTER – FLYING SUPER SIZED BUMBLE BEE ON MARS
This is another lightweight flying machine that could take off from a surface lander, and again, suitable for a small lightweight prototype mission.
Video of Robert Michelson’s entomopter.
On Mars it might be easier for machines to fly with insect type flight with rapidly beating wings, using the bumble bee wings vortex effect for lift. On Mars that can work scaled up to wings a meter across because of the thin atmosphere also assisted by the low gravity. That’s the idea of the entomopter.
HOPPING MICROBOT SWARMS TO EXPLORE SURFACE AND CAVES
Yet another idea, even smaller robots.
Small, spherical microbots filled with minature fuel cells, instruments and an artificial muscle for hopping
Microbot Madness: Hopping Toward Planetary Exploration
They could fit a thousand of these into 174 Kgs.
WHY NOT GO OUT ON A LIMB AND TRY SOME INNOVATIVE IDEAS
So – would be rather cool if they went out on a limb and borrowed some of these more innovative ideas.
There are so many ideas around for ways of exploring Mars. But the big space agencies don’t tend to explore them much – they prefer to keep on with tried and tested ideas for the main part.
But, given the high fail rate of missions to Mars so far – I think is not at all clear that the approach we have used so far is the best one.
IDEA – DESIGN AROUND MANY LIGHTWEIGHT MISSIONS AT LOW COST RATHER THAN BIG FLAGSHIP ONE OFF MISSIONS
At present, our approach for Mars missions – for NASA, ESA and Russia, all the same idea – we rely on complex expensive missions, send just a single rover or orbiter each time. Then if it fails – it is a major setback and sometimes leads to cancellation of the whole idea as with Beagle II.
NASA has had a string of remarkable successes to Mars surface recently – but even NASA has had many failed missions to Mars also.
And especially flying or balloon rovers may be worth exploring because they give you a chance to skip one of the most dangerous steps.
Also – lightweight technology demo explorers on Mars. Well worth doing and would show to the world that they have done something interesting and are pioneers in space exploration.
I expect that eventually we will have humans in orbit around Mars exploring it by telerobotics. And will have maybe dozens of robots on the surface for them to control.
If so – most likely international partnership perhaps involving all the major space faring countries to pay for it – it’s an expensive mission costing surely many billions to develop. Perhaps something like the ISS around Mars.
Then other countries then can join in by launching mini rovers to the surface of Mars for the astronauts in the international expedition to control.
(this article originally appeared as my answer to a question on quora)