This video is supported by Brilliant! Hey, Hey Marcus House with you here. If you’ve been
watching along here for quite some time, you will know that the team and I have been releasing some
deep dive videos that look into the complexity of long duration crewed spaceflight. The primary
concerns of course being the health of astronauts aboard these missions. We’ve talked in depth about
the damage of various types of radiation and the recommendation for strong shielding. We’ve also
covered generating at least some reasonable geforce to mitigate the health issues that
arise from being weightless for long periods of time. You’ve only got to read Scott Kelly's Book
Endurance to know how detrimental that can be. To do all of this stuff right and protect those
squishy fragile human bodies on board, it is going to take a lot of equipment. That also means a lot
of mass. Changing the trajectory of all that mass has huge propellant requirements, and if
you need to send many thousands of tons of that on every trip, it is going to be hugely expensive.
What if I told you though, that once we get all this up to the required speed for the journey,
that was it. A reusable station taking trip after trip, only needing tiny course corrections from
time to time? Well, with a nod to Buzz Aldrin, may I present to you the Atomic Powered, Shielded,
Spinning Starship Mars Cycler! Ok, let’s talk about cyclers. No,
not those… these. When you place something, say, a Tesla Roadster, a spacecraft,
or a complete station into a special trajectory between two planets, you get this! A cycling
trajectory that can pass back and forth between them. Only needing the odd correction adjustment
to stay on the path indefinitely! Yep. Minimal propellant needed once it’s on the right path.
The concept isn’t new of course. The use of cyclers was considered in 1969 by
Walter M. Hollister, who proposed a concept for an Earth–Venus cycler. He was the first to experiment
with the possibility of placing a spacecraft on a trajectory that goes back and forth between Earth
and Venus indefinitely, again, with barely any fuel needed other than small course corrections.
Then came Buzz Aldrin with an updated idea. Yes, the same Lunar Module pilot who landed on
the moon for the first time in 1969 alongside Neil Armstrong. Aldrin was not just a pilot,
he was the first astronaut with a doctoral degree in astronautics. Even earning the
nickname "Dr. Rendezvous" by his peers after his thesis. Aldrin built upon this cycler concept,
proposing his own in his 1985 paper. This specific concept was for a Mars Cycler and
as you might have guessed, this one was named the Aldrin Cycler, or as Buzz describes it,
“a subway-in-the-sky between our planet and our future second home.” Sounds exciting doesn’t it?
Well, I certainly think it is. It’s a station that once in orbit can travel to Mars and back with
very little propellant. It uses gravity-assists flying by Earth and Mars in just a precise way,
that the orbit around the sun is adjusted precisely the next leg of the journey. Due
to the case it doesn't need loads of propellant to change its trajectory, it could be thousands
of tonnes and it wouldn’t matter outside of initially getting it up to speed. It can
carry heavy radiation shielding, modules for artificial gravity, an ample amount of space,
surplus consumables, and all the comforts recommended for the brave crew on board.
Now there is a pretty lengthy list of other different Earth Mars Cyclers, some taking many
years and having various speed and trajectory pros and cons. This one as an example is the
S1L1 cycler which travels from Earth to Mars once in a little over four and a half years.
The Journey to Mars, takes only 5 months, but to get back to Earth, it needs to take another
two orbits around the sun, doing an Earth gravity assist in between, and then re-encountering the
Earth for the next crew to make their journey to the red planet. At this point, having used
almost no propellant, the cycle starts again. The duel Aldrin Cycler specifically though I
think is the most interesting. This provides the benefit of having not only
a fast journey from Earth to Mars in what many refer to as the “Up” cycle shown here,
but also a similar fast “Down” cycler to return from Mars. By using these two separate cyclers,
we can have a much faster trip to Mars and back every 2.13 years. Yea, that is a lot quicker.
For the sake of this video, I’ll name the two cyclers Transfer Station Alpha for the Earth
to Mars Up-cycler, and Transfer Station Bravo for the Mars to Earth Down-cycler!
Now immediately, you may see an issue that comes along with a cycler system. They are
not stopping at Earth or Mars. No… they instead scream by very rapidly. Think of scenes from
the movie The Martian, where supplies needed to be hurled off at huge velocities to catch
the Hermes station screaming by. We need to catch that station, and catch it fast. Well,
introducing small, light, efficient spacecraft simply to transport astronauts on board as quickly
as possible to minimize their overall exposure. As this great paper exploring this topic puts it,
these are the taxis! Probably largely made of light weight materials and carbon composites,
minimal shielding and high Specific Impulse engines like the RL10. Essentially a vehicle
with the speed capability or Delta V requirements that we need to catch the station. Remember,
we only need to take the astronauts, and enough food and water for their leg of
the journey. There really isn’t any reason why other cargo vehicles with low powered,
high efficiency engines couldn’t have supplied the station well in advance anyway. So, here is the
challenge. Transfer Station Alpha will swing by Earth at a whopping speed. This table here assumes
you are departing from a lunar radius orbit, and these are the delta V requirements to catch it.
A fascinating read if you want to explore deeper by the way. Link to that is in the description.
This is where our journey begins. A journey that will take us hundreds of millions of kilometers
away from home. Once docked and on board Transfer Station Alpha, the benefits are clear. A faster,
safer journey to Mars taking around 5 months or so. Why safer? Well, the quick transit time for
one. Many NASA plans talk of 7 month trips from Earth to Mars, so this knocks a few months off
that, but more importantly, we can load the transfer station with much better shielding
from Galactic Cosmic Radiation. The dangers of which I’ve talked about in this previous
video. Loading many tonnes of shielding on a simple one shot mission would be very costly
and it wasteful doesn’t it. I couldn’t agree more. But, putting it on a cycling station making many
trips makes a lot of sense. Sure, it takes a lot of initial velocity to get it up to speed,
but using high efficiency low-thrust propulsion options like Solar-Electric or nuclear engines,
that is the key. What else would make it safer? Some artificial gravity to simulate Mars gravity.
Artificial gravity in space is highly desirable for several reasons. Firstly, it helps alleviate
the detrimental health effects like muscle atrophy and bone loss on long missions. By simulating the
gravitational forces humans will experience on Mars, it would promote physical health and reduce
the risk of long-term complications. Secondly, just for convenience! Crew comfort is important,
and having some partial gravity enabling the crew to perform everyday tasks ina similar way to here
on Earth. Eating, sleeping, and exercising in a familiar environment would be wonderful for
morale and overall productivity. There’s a lot of ideas on what kind of space craft could be
built to achieve this. Everything from rotating space stations like in 2001 a Space Odyssey,
right up to a more recent movie Stowaway where a huge tether had the space station on one side, and
a equally massive propellant tank on the other as a counterweight, all spinning slowly. Neat idea.
So with their reasonably fast trip to Mars done and dusted, it is time for all astronauts to
board a modest re-entry vehicle, decouple from the transfer station screaming by, and make their way
to the Martian surface using the atmosphere to aggressively aerobrake to slow down,
and a propulsive landing on the surface. This is the beginning of a lengthy and productive time
on the surface. Plenty of time before they need to catch the next ride back home. That is the
reason why we are here though, and it is time to unlock the many mysteries that could redefine our
place in the universe. Exploring the martian landscape, possibly unearthing signs of basic
extraterrestrial life? The most profound result may even be the huge revolutions in technology,
medical equipment and sustainable living required to attempt this. All colossal benefits here at
home while we witness the ultimate epoch defining adventures on another planet.
Transfer Station Alpha after passing rapidly past Mars continues on the rest of its almost 21 month
elliptical journey to complete its circuit all the way around the sun to intercept the Earth
again. This sped up version shows quite clearly that each gravity assist actually rotates the
entire orbit. That results in something quite similar to this neat geometry after four full
orbits around the sun. Pretty cool huh!? So, moving onto the second Aldrin
Cycler, Transfer Sta-tion Bravo! This is essentially the same sort of idea,
but this orbit intercepts with Mars as it plummets in toward Earth. That means a similar 5 month trip
all way back home. The issue with the return on this leg of the journey, is that the taxi required
to catch Transfer Station Bravo is way more than what was needed for the earth leg of the trip.
In this scenario, it is assumed you will be leaving on your taxi from a station on or
around the moon Phobos orbiting high above Mars. Obviously to get to this station,
astronauts would have launched on a light weight Mars ascent vehicle first. The movie The Martian
goes for direct ascent here but either way, we need a highly efficient taxi designed to simply
catch Transfer Station Bravo. Just look at the delta V requirements for this. Over double what
was needed when we caught Transfer Station Alpha at Earth Earth. It is still possible
with chemical propulsion, but a much bigger challenge. At this point though we may well have
nuclear engines providing a much more efficient option. This announcement by NASA in January was
a positive sign of the future here. With DARPA they are collaborating to, we hope, successfully
demonstrate a nuclear thermal rocket engine in space for the first time ever. All with the goal
of creating options like what we are talking about. With propellant generation facilities
on the moons of Earth and Mars, creating reusable vehicles should all be possible, and it is just
incredible to imagine. With Aldrin's Duel Cycler system in action there would always be a crew on
Mars in a 44 month cycle. The concept suggests that 26 months into the crew's stay on Mars,
they’d welcome the next from the following cycle, spend 18 months with them, and then head home.
As with any complex idea, there are some negatives. Because both transfer stations
are in a very well timed cycle, there is only one chance every two and a bit years to make
the trip. The departure and arrival times are absolute with almost no margin, governed
by the iron fist of Newtonian mechanics. To make this safer, would there need to be backup rescue
taxis or some such failsafe? If such a cycler system does one day become a reality, perhaps
there could be a string of them all riding the cycle together providing extra safety measures.
Of course, it will not be easy making these mammoth cycling stations. Making one alone would
take tremendous resources. However optimistic you might be, it could take decades to build
something of this kind. We would certainly need a fully functioning lunar base. One
that is technologically sophisticated enough to extract regolith, create and supply propellant
and support a gigantic industry of workers on the lunar surface. Then, there is the big challenge
of constructing a vehicle like this in orbit. That alone requires technology far in advance
of what we have right now. Once constructed, you then need to establish the initial trajectories.
Accelerating the monstrous mass thousands of meters per second is going to be a challenge. I
imagine a combination of nuclear engines and ion propulsion would be a requirement there. Before
we can even contemplate doing any of this, the absolute first key is affordable mass to orbit,
and if SpaceX’s dreams of a fully reusable Starship becomes reality,
that is the beginning of the change that can make everything we are talking about here a reality.
It is a super inspiring thought proposed long back in 1985, when reusable rockets were just science
fiction. Aldrin’s dream was to future-proof the Mars program. As he said “this system would go a
long way toward politician-proofing the Mars program”, simply because it is a long term
investment that would stretch many presidential terms. Similar in a way to what has been achieved
with the international space station. A common question I get a lot and one
we’ve hinted at a few times in the past, is, could you make a similar sort of shielded station with
artificial gravity largely from Starships alone? [Ad Start] Just to work out what is practical
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subscription. Thank you Brilliant! [Ad End] Ok, so could a station built largely with
Starships work as a Mars cycler and also provide adequate protection for its crew? Well in theory
it totally could. If we take all of the ideas discussed throughout the last few deep dive
videos we get this! Firstly we would want to construct a giant rotatable frame in lunar orbit
that will provide the main body of the structure. Wack a few docking collars onto that Central Hub,
send loads of shielding mass up from the moon to encase the living areas. Once assembled, hook up
a highly efficient space tug ready to delicately hurl it off into its long term trajectory. Dock
whichever variants of Starship you require for the first leg and away you go! That’s
it right. No problem!? Look, who knows how the future will play out, but it is fun to imagine.
The diameter of this alone would be over 215 meters which is about twice the International
SpaceStation. As already mentioned, artificial gravity is important, and at this scale we’d have
the luxury to spin this up and get it rotating to simulate Mars gravity. Big shielding collars over
the habitable space there to block the majority of galactic cosmic radiation as well. Everything
here to keep the entire crew comfortable. Probably not with crews of 100 packed into
each of them like Elon used to mention. 10 or 12 in each ship would I think be plenty.
So yes, what do you think of this concept? With the potential that Starship brings to
the table could the door to private and government options open wide to make any
of this practical? Or will the concept be forever a dream out of reach. Of course,
there are many different solutions for interplanetary travel, and this was
just one interesting idea that I’ve been researching heavily over the last year!
I’d like to say a big thanks also to Dennis Chamberland for giving me a hand with some
research material. Witha fascinating career as a NASA Space Life Sciences engineer,
an aquanaut, and the Mission Commander for seven NASA underwater missions,
I appreciate your time mate. If you love this sort of stuff check out his books from the link below.
I hope you enjoyed this video! If you did, don’t forget to hit subscribe to follow
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If you want to continue the journey, check out our related videos on radiation, artificial
gravity options and much much more. Thanks for watching, and I’ll see you all in the next video!