The thing that makes space travel difficult is that everything we used to do it is so massive !!! To get to the orbit , let alone to that of Moon or Mars, you have to lift a lot of very heavy stuff. So how do you do that ? How do you escape gravity, the force that holds us to the Earth ?
Well…let’s talk !
Travelling through space is Hard. That’s why NASA’s Space Launch System will have to be the most POWERFUL ROCKET in history. How is SLS able to meet the challenges of exploring deep space ? Well, when it comes to our journey to Mars and beyond…there’s a whole lot to consider.
Let’s talk about Low Earth Orbit first, which, compared to Mars, is relatively close. The International Space Station is only 220 miles over our head.
For years the space shuttle got us to Low Earth Orbit. It weighed about 4.4 million pounds and could carry 54000 pounds of cargo into orbit. That’s only about 18 family sedans worth of stuff and that’s because, of that 4.4 million pounds of Shuttle’s weight, 3 million pounds was fuel. The shuttle’s fuel weighed more than twice the shuttle, its external tank and the solid rocket boosters combined ! It’s like driving a car that requires a 1000 gallons gas tank.
The shuttle got us to Low Earth Orbit, but what about the Moon ? Well the Moon is 240,000 miles away, which is a 1000 time further than the shuttle can take us. Thankfully we don’t need a 1000 times as much fuel. The cool thing about space is you can coast. We’ve just gotta go fast enough to reach the Moon and let its gravity pull us into orbit. So you don’t need a 1000 times as much fuel but you do need more. But the more fuel you have, the heavier your vehicle has to be and the heavier your vehicle is, the more fuel you need.
Tricky, uh ?
The Saturn V is the rocket that took us to the Moon. It could carry 260,000 pounds of cargo into orbit. That’s almost 5 times that the space shuttle could carry and it could carry a 100,000 pounds to the Moon. However to do that it weighed 6.5 million pounds and 6 million pounds of that was fuel. That’s right! To get to the Moon, we had to build a vehicle that was over 90% fuel. Then what about Mars? When we go to Mars, it’ll be about 50 million miles away, about 200 times further away from the Moon.
The first version of SLS will get us to the Moon. The second version will be the tallest rocket in history, it’ll produce the greatest thrust and it’ll get the most stuff into the orbit. The second version of SLS will have about the same fuel as the Saturn V; while the Saturn V could only go to the Moon, the SLS will go to Mars.
NASA’s SLS is building on the foundation laid by the Saturn V and the Space Shuttle. In fact its current design looks a little bit like a mash-up of the Saturn V and the Space Shuttle. That’s because it is taking technology from both and combining them to go further than they ever could.
Let’s talk about how the SLS is like the Saturn V…
The SLS is a stage rocket like the Saturn V. Once all of the fuel and a stage is used up, that stage is dropped to reduce weight. The two are also of similar heights. The first version of SLS will be 322 ft. compared to 360 ft. of the Saturn V. The Saturn V had 3 in-line stages where the SLS will only have 2. But the SLS does have two boosters on either sides and you know where those came from. The Space Shuttle’s solid rocket boosters produce the most thrust of ANY rocket engine in history. The SLS will use the same boosters but they’ll be even more powerful because they have an extra Fifth segment containing propellant. The SLS’s two boosters combined will produce almost as much thrust as all five of the Saturn V for stage engines. The SLS is also using the Space Shuttle’s main engines, four of them at the bottom of the center of the rocket. These engines have been used since 1981 although they’ve been upgraded, improving performance and saving NASA money. They’re also hugely reliable. Between ground tests and shuttle flights, they’ve already clocked up 1 million seconds of “hot fire” time. And that’s before SLS ever lifts off.
So NASA has built some pretty incredible vehicles but the Space Shuttle couldn’t leave LEO and the Saturn V only went to the Moon. How will the SLS combine their capabilities and get to Mars? It’s because even though the SLS is built on previous technology, NASA’s improved it. Think about your phone for instance, a phone from 2007 looks a lot like the ones we have now and they do the same basic job. However, the new one has more power, is more efficient and can plainly just do more thanks to improvements in technology. Similarly, the first version of the SLS will weigh a million pounds less than the Saturn V but it’ll get to the Moon. The second version will weigh as much as the Saturn V, it’ll carry the same amount of fuel but it’s far more fuel efficient, and that’s the key to getting to Mars.
Technology has changed a lot since the Shuttle program began back in 1972. Back then, this was considered a “Smartphone”.
To sum up, the physics of sending a rocket into space hasn’t changed but our engineering has. NASA has figured out how to build on legacy technology while also improving it. It’s like putting a roof on the house, and when you do that, you don’t tear up the foundation.
Next time, we’ll see how the SLS is able to generate as much power to launch itself due Mars! Until then…stay tuned.
