Name: The Insane Engineering of the Perseverance Rover
Uploaded: 2021-04-12T12:05:51.000Z
Duration: 19 min 42 s
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On July 30th 2020, a United Launch Alliance  Atlas V rocket lifted off from Cape Canaveral,  

Florida. Carrying the next generation of Mars  Exploration Vehicles.The Perverence Rover  

And, today, on February 18th 2021, if all  goes to plan, the two vehicles will land  

safely on the Martian surface after their  long 7 month journey to the Red Planet.

Only about 40 percent of missions  sent to Mars have been successful  

and perseverance will have to endure a  vicious and complicated landing sequence,  

as it's creators wait, powerless to intervene,  waiting for news of its success back in Pasadena.

Perseverance rover is the largest and heaviest  rover JPL has ever sent to Mars. Heavier than the  

Curiosity Rover by 100 kilograms, and with that  extra weight comes a whole host of new gadgets.

This isn't just some slightly upgraded version  of the curiosity rover. Perseverance is  

benefiting from almost 10 years of advancement  of technology. It's packed with fascinating and  

novel technologies that will form a stepping  stone in humankind's eventually first steps  

on the surface of the red planet. This is the  insane engineering of the Perseverance Rover.

Perseverance, hopefully,  is now safely on the ground  

where it will live a long  illustrious life on the red planet.

We have learned some things from the  Curiosity Rover that will hopefully  

help Perseverance avoid the struggles  it's predecessor is experiencing.

We have made an entire video on the struggles  of the Curiosity Rover wheels and how they  

have been gradually falling about on the harsh  Martian service. In the end the engineers at JPL  

did not opt for shape memory alloy wheels  like the ones we discussed in that video,  

but simply increased the diameter of the wheels,  decreased their width and increased the thickness,  

while incorporating sturdier curved threads  that will better resist crack growth than  

Curiosity's sharp cornered threads. [1] They  have also forgone the rectangular cut outs which  

imprinted morse code, spelling out the Rover's  origins, in the rusty dirt of its new home.

There is a whole host of new software upgrades  too. Like the algorithm that determines when  

to open the parachute. In the last mission the  parachute simply deployed when the target speed of  

1450 kilometres per hour was reached, after  most of the hypersonic re-entry speed of  

21,450 kilometres per hour had been bled off. [2]

For perseverance, JPL wanted to increase the  accuracy of their landing, so this time around  

the chute will open when it is approaching  the optimal trajectory for the landing site.  

It will also be scanning the surface of the  landing site and correlating those images to  

it's pre-existing map to allow the skycrane  to choose the best landing site with minimal  

obstacles. Perseverance's ground navigation  systems have also been significantly upgraded,  

with it's optical sensors feeding data  to a machine learning vision algorithm.  

Allowing Perseverance to find it's own  path through the rough terrain of Mars,  

where Curiosity had to constantly stop and start  with help from it's earthbound controllers.

Perseverance is benefiting massively  from the past decade of improvements  

in autonomous flight and driving developed  by the drone and automotive industries.

This will mean Perseverance will be able  cover much more ground during its life,  

here, in Jezero Crater [3]. A massive crater  that was once home to a lake the same size  

as Lake Tahoe. You can see the  remnants of this ancient river bed  

and delta spilling into what may have  once been a habitable body of water.

It is here that Perseverance will scour for  signs of life. Before we get into all the  

gadgets it will use to do this, let's look  at how Perseverance will power them. The  

Perseverance Rover features the same Radioisotope  Thermoelectric Generator as the Curiosity Rover.  

RTG's work by converting the heat from the  natural decay of a radioisotope into electricity.

It uses a simple principle called the  Seebeck Effect to generate electricity.  

[4]The seebeck effect essentially allows  us to generate an electric current  

through a heat differential, as charge  carriers, both electrons and electron holes,  

will move from hot to cold. So  if we have two semiconductors,  

one with charge carriers in the form of electrons  and one with charge carriers in the form of holes.  

A potential difference between the two  semiconductors will form when a heat  

gradient is applied. This potential difference  causes a current to flow in the external circuit

These two semiconductors need to be both  thermally insulating, to ensure this heat gradient  

is maximized, but also electrically conductive  to maximize the current. These two material  

properties are typically linked. Copper is  both a great electric and heat conductor,  

while iron is a poor electric and heat conductor.  Having a single material that is a great electric  

conductor and a poor heat conductor is extremely  rare. For this reason two unique materials are  

used for the p and n type semiconductors. Lead  Telluride for the n-type and an alloy commonly  

called Tags for the p-type, which is formed from  tellurium, silver, germanium and antimony. [4]

Now we just need a consistent  heat source. Thankfully  

radioactive substances  generate heat as they decay.

The perseverance rover RTG uses 4.8  kilograms of plutonium dioxide as it's heat  

source. This radioactive material primarily  produces alpha waves, which is essential,  

as this form of radiation is most efficiently  converted to heat in a compact space. [5] [6]

While Plutonium 238 also releases  minimal beta and gamma radiation,  

decreasing the weight of shielding needed to  protect the electronics onboard from these more  

powerful kinds of ionizing radiation, an essential  characteristic for a lightweight spacecraft.

The Plutonium 238 is also formable into a ceramic  like material that will break into large chunks,  

rather than being vaporised and spread in the wind  during a launch failure, where it could be inhaled  

or introduced into the food chain. [7] [8]

The electricity this unit can  provide will gradually degrade,  

from it's maximum of 110 watts at launch,  as its plutonium heart naturally decays.  

Losing half of its energy every 87.9 years, which  is much longer than the 138 day half life of the  

early polonium 210 RTG prototypes. [8] Another  advantage of Plutonium 238 for this application.

This will power all the instruments onboard,  

like the Moxie instrument, which  is one of the new devices I am  

most excited about aboard Perseverance. Moxie is a new oxygen generation device  

that will test a vital technology  for any future human mission to Mars.

You may wonder, like I did, how is this  different from the oxygen generation present  

in the international space station. There is  obviously a limited supply of oxygen there.  

Why do we need to test this  new technology on Mars,  

when we obviously have a tried and tested  method of creating oxygen already. Surely?

The international space station does not  really recycle oxygen. Oxygen is created  

on the international space station through  the electrolysis of water. [9] This produces  

hydrogen and oxygen. The hydrogen is then reacted  with carbon dioxide to form water and methane.  

The methane is then simply exhausted into space  while the water is fed back into the system.

The international space station  requires regular resupply of water  

as we are losing 2 hydrogen atoms  for every oxygen molecule we create.  

This is not a closed loop system and water is  a pretty heavy material to be shipping to Mars.

The perseverance rover will test  a new method of oxygen creation  

using this device which will use solid  oxide electrolysis to instead break  

the plentiful carbon dioxide in the Martian  atmosphere into Oxygen and Carbon Monoxide.

It's operation is fairly simple. Air will be taken  in through a dust filter by a specialized pump  

designed to be as light and compact as possible  called a scroll pump. [10] Scroll pumps are  

pretty cool. They consist of two spiral scrolls,  one stationary and one rotating. Air is taken  

in at the inlet here and as the secondary  scroll rotates in traps and squeezes air  

against the primary stationary scroll. This  continues to happen as the volume between the  

two scrolls decreases down the spiral, causing an  increase in pressure, in this case it takes the  

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