SpaceX, the aerospace company founded by Elon Musk, is working diligently on an ambitious project: to definitively establish people on Mars.
To help make this vision a reality, Musk's company is developing a colossal and completely reusable system called Starship.
The starship was conceived as a 180-foot-tall spaceship that will ride in orbit on top of Super Heavy, a rocket of about 220 meters in height, according to Musk's latest descriptions.
The spaceship is designed to be supplied at low Earth Orbit to push 100 passengers and more than 100 tons of cargo at a time to Mars.
But the success or failure of the launch system – and by extension the Musk plan to support the human race ̵
A change concerns the construction of the spaceship from stainless steel alloys instead of carbon fiber composite materials.
But the most surprising change, according to experts in the aerospace industry, is the way in which the starship will try to prevent itself from burning in the atmospheres of Mars and the Earth.
Instead of relying on thousands of heavy ceramic tiles to shie the spaceship from the heat, as NASA did with its space shuttle, Musk says the spaceship "will bleed" rocket fuel through tiny pores to cool.
In theory, putting liquid between Starship's steel skin and hot plasma as it lifts atmospheric gases would prevent the destruction of the ship.
But if SpaceX is able to extract a launch system of this unprecedented size and design remains to be seen, says Walt Engelund, an aerospace engineer and director of NASA Langley's Space Technology and Exploration Directorate.
Scale entry, descent and landing are something that NASA has had to challenge for decades: we spent a lot of time and we focused on how we could do it on Mars, "said Engelund a Business Insider.
"We have landed the metric curiosity rover: this is the greatest thing we have ever laid on the surface of Mars."
To go from the Martian landing of a robot of dimensions of a car to a ship the size of a building full of humans, said Engelund, is "a couple of orders of magnitude" – about 100 times – harder than the landing of Curiosity, who said "is probably one of the hardest things we've ever done at NASA. "
" It will not be easy for us or SpaceX, "Engelund said
Because the spaceship turned into a vy-metal rocket ship
Musk thinks to be able to build a self-sufficient city on the red planet by 2050 . He wants the individual tickets on Mars to be cheap like a house on Earth and return travel is free.
The Starship-Super Heavy launch system is the way that Musk plans to achieve that goal, and said that switching to stainless steel alloys is a way to contain the costs and build the system more quickly.
"The spaceship will look like liquid silver," Musk said of the December change, adding that the ship will have a mirror-polished finish to help reflect heat – a cool factor literal case
Illustration of the next Starship spaceship of SpaceX and Super Heavy (central) rocket next to the NASA Saturn V rocket (left) and SpaceX Falcon 9 rocket (right). (© Kimi Talvitie)
In an interview with Popular Mechanics Musk explained that steel is about 67 times cheaper than the weight of lightweight composite materials and superstrosi in carbon fiber that SpaceX had planned to use until September. Steel is also easier to work with than carbon fiber, allows faster prototyping and better resists intense heat.
In addition, Musk said that the strength of steel is "increased by 50%" when it touches ultra-cold liquids, including the cryogenic methane and oxygen that the starship could use to push through space.
The problem with steel, however, is that the material is dense and heavy. At least one of the early versions of the General Dynamics Atlas missile, which was made from metal, crumpled under its weight on a launchpad.
Yet Musk has suggested that the use of SpaceX steel is very different and will make the stellar ship redesigned stronger, more resilient and less heavy. Ultimately, he said, material change will improve missile ship performance compared to old design.
"I am confident that a stainless steel ship will be lighter than advanced aluminum or carbon fiber, due to its weight resistance to temperature and the reduced need for thermal shielding," Musk tweeted to January.
But as resistant as it is to steel, it is not invincible, especially when it forms the skin of a spaceship that screams through atmospheric gases.
and bleeding for survival
The starship could enter through the atmospheres of Mars and Earth at 19,000 mph . At such speeds, Musk said parts of the vessel's belly, like his nose, could be exposed to temperatures of around 2,700 degrees Fahrenheit.
There is enough heat to destroy the steel alloy that Musk said SpaceX could use for Starship's outer skin. Called 310S, the material is often labeled as a heat-resistant metal, since it has a lot of chrome and nickel mixed in it.
(It is no different from steel used in cooking pots and pans.) But the 310S steel still starts to react with oxygen and corrodes at about 2,000 degrees and melts at around 2400.
The spacecraft needs protection from intense heat, which is why Musk's plans require Starship's body to cool using liquid fuel during landing.
Musk said Popular Mechanics who decided to give up the space shuttle thermal cards to save weight and avoid the risk that a damaged or lost tile could compromise a heat shield.
Instead, he explained, the starship would "bleed" or sweat the rocket fuel from small holes in its steel skin, and that the liquid layer would carry away the scorching heat of the entrance. Atmospheric.
"On the wind side, what I want to do is have the first regenerative heat shield: a double-walled stainless shell, like a stainless steel sandwich," said Musk.
"Flow both fuel and water in b between the sandwich layer, and then the micro-perforations to the outside – tiny perforations – and essentially discharge water, or you could drain fuel, through micro-perforations to the You would not see them unless you approached them. "
He added that the heat shield would do the double work by strengthening Starship's steel body.
"As far as I know, this has never been proposed before, Musk said
The experts told Business Insider that Musk is right about the fact that no spacecraft ever entered orbit and returned to Earth using a similar heat shield, but the concept of "perspiring" perspiration or thermal protection is not new, and
Musk says that the launching system of the starship will be polished to a mirror. (© Kimi Talvitie)
Breathable or "active" cooling has been around for millions of years in the form of mammalian skin When the temperature of the human body increases too much, for example, the microscopic pores switch off sweat.  This liquid evaporates to take away excess heat and prevent overheating.
As for the sweating spaceship, NASA started playing with the ispi cooling system to nature before landing astronauts on the moon.
the transpiring cooling is not new. It has been around for decades, "said Engelund.
A patent filed by NASA in 1965 analyzed using the urine of the astronaut to cool a heat shield on the bottom of a space capsule.
in 2006, the space agency spent at least $ US70,000 for research on an inflatable, transpiration-cooled heat shield, which could help the spacecraft landing on Mars.
Even the spacecraft "sweat" played a part in the Cold War armament race Defense test: launch of a nose tip cooled by perspiration for return vehicles.
These re-entry vehicles are flown into space on top of missiles intercontinental ballistic, fall into the Earth's atmosphere thousands of miles at the time and hit distant targets with nuclear warheads  But according to historical documents of the US Air Force, the project was canceled later on the years' 70 due to limited funding and "design issues that had plagued the development effort". The engineers instead opted for a "simpler ablat" "heat shields that isolate a vehicle burning during the return.
The information on the problems of the transpiring thermal defense shields are mostly classified.
But George Herbert, an aerospace engineer who researched the military uses of launching into the vehicle space, told Business Insider in an e-mail that "reported and known problems include blocked perspiration holes."
In other words, a common challenge faced by the adolescent skin: clogged pores
& # 39; What happens if a bird poop on your rocket??
Several experts have told Business Insider that they are worried about the blocking problem in Starship's heat shield design.  "You can imagine that it would not take long to clog something like that, if they were microscopic pores," Engelund said.
Dwayne Day, who helped investigate the loss of NASA's Columbia space shuttle and its crew, imagined an annoying one the most common scenario that the starship would have to face at any launch site on Earth.
"And if a bird poops your rocket and connects some holes, and then when it's coming back, no refrigerant comes out of those holes and that section of the vehicle overheats?" Day wrote in an e-mail to Business Insider.
Engelund said he saw problems with the cooling systems clogged in tests performed inside the hypersonic wind tunnels.
During these experiments, scale models of vehicles are placed in the tunnel – which can blow air thousands of miles at the time – to study how they behave. Some of the tests involved heat shields pumping liquids through the channels just below the model's skin to cool it, but not all models survived.
"I have seen cases where you get a clogged channel … and it will immediately cause burns," Engelund said. "A model disappears into a hypersonic wind tunnel, almost vaporises, there is so much energy and so much heat."
Musk said that using methane as a refrigerant could be better than water.
"Rapid vaporization of water can counter-intuitively cause it to block and block cooling channels," he said in a Tweet last month .
But also Engelund sees the challenges with the methane option. When exposed to high temperatures, the carbon atoms contained in the hydrocarbon fuel (such as methane) can "coke" or adhere to and become solid. Such debris can therefore block thin structures such as pores.
"I would be very concerned about this," Engelund said, adding that another major concern would be impurities in fuels, which can also lead to clogs.
One possible way to deal with these problems, Engelund said, could simply be to add more pores than it seems necessary, "in the event that a small percentage of the perforations become clogged or that the channels run cooler to such perforations."
In addition to issues like bird droppings and clogging, there is the fine dust blowing on Mars. This could be allocated to Starship's fuel pores, and it might be difficult to find and remove those blocks while on the red planet.
"The inspection and certification, in general, would be a concern for a large system operating on a scale like that – especially on Mars, where you do not have access to a large trestle or towers to go up and inspect" Engelund said.
"I suppose you could use drones." Maybe it's something he's thinking about. "
Can Starship get hot?
Musk shared only fragments of Starship's latest design and did not present a complete picture to the public, as he did in the past. (The renderings shown in this story are courtesy of Kimi Talvitie a 3D artist.
– Elon Musk (@elonmusk) 25 January 2019
Ma Musk said in December that he "gave a detailed explanation in March / April", awaiting the launches success of a "test hopper" prototype that the company is building in Texas
Meanwhile, Musk has shared a video (above) that seems to show the test of a metallic heat shield for Starship It is not yet clear how much SpaceX research has done on the concept of transpirational cooling.
"It is a big risk if they have not worked to qualify and validate what they want to do," Herbert said
"But if they have done, it could be a real winner for them new design. "
If it does not work, Engelund said, it's not necessarily a dead end for Musk's starship.
" You might find it unsustainable or too expensive to certify or test, and you might find an idea better, "said Engelund." He was really good at it. "
SpaceX also expects constant changes and modifications while engineers work to make Starship a reality.
" We are using the same rapid iteration # 39; design approach that led to success on the Falcon 1, Falcon 9, Falcon Heavy and Dragon programs, "a business representative in an e-mail told Business Insider, referring to the latest rocket and spaceship of the company.
But SpaceX refuses any comparison between the starship and the curiosity of NASA rover
"Curiosity was pushing the limits of the Mars technology (1970-1945) including an architecture EDL sp echos based on the parachute, "SpaceX said.
"We are taking a completely different approach, taking advantage of what we have done with Falcon 9, and have ample opportunity to demonstrate it on Earth before flying to Mars."
Despite the high obstacles SpaceX seems to face in its mission to launch and land the starship on Mars, no expert we talked with the SpaceX system said It was not plausible.
"They have surprised many people and have a lot of smart people working for them, and Elon seems to be really committed and dedicated to this," Engelund said.
"Maybe there are some things we could do with them, I suspect there will be."
This article was originally published by Business Insider.
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