Picture a rocket shooting into space.
Is it a towering beast that dwarfs nearby buildings and palm trees?
That makes sense.
The rockets that go to the International Space Station
and beyond are closer to the height of a rollercoaster than they are to a house.
But you don’t have to be that large to get to space.
Today, we’re going to celebrate the smallest rocket to ever orbit the Earth:
The Japan Aerospace Exploration Agency’s SS-520-5.
Launched back in 2018, its success could help usher in a new era
of getting stuff where you want it in space, when you want it, but in space.
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Now, I know what you’re thinking.
“That still looks pretty big to me”.
Well, you are a human.
Probably.
So even this tiny record-holder is going to look large compared to you.
The SS-520-5 stands just 9.5 meters tall and 0.5 meters in diameter.
But that means It’s skinny enough to hug!
Meanwhile, you could try hugging the likes of NASA’s Space Launch System,
or SLS, which sent the Artemis I mission around the Moon back in 2022.
But it would probably feel more like you’ve just kind of
smushed yourself up against the side of it.
The enormous SLS is over 98 meters tall,
which is over ten SS-520-5 rockets stacked on top of each other.
And that massive difference in size all comes down to the job each is built to do.
You can divide space-faring rockets into three main types.
Deep space rockets like the SLS use their extreme size to pack in
a bunch of fuel and the super powerful engines needed to push people
and cargo into, as the name suggests, deep space.
Although NASA’s idea of what deep space is might not match yours.
The Moon is considered deep space.
Which, I mean, I guess…
The closest relative to the SLS might be the Saturn V rocket,
which took Apollo astronauts to the Moon in the late 1960s and early 1970s.
And it was even larger, at 111 meters tall.
But groups around the world have launched rockets
into deep space without these giants.
Rockets like the Atlas V are built to carry scientific equipment,
not people, so they can be smaller, around 60 meters tall.
The most common rockets used today are orbital rockets.
These take cargo, whether that’s satellites or astronauts,
into space with enough speed for them to stay in lower orbits around the Earth.
The Russian Soyuz and SpaceX Falcon 9 rockets,
famous for their trips to the International Space Station, are both orbital rockets.
They’re between 45 and 75 meters tall, and are about half the diameter of the SLS.
That’s still way too big to hug...at least it is if you’re by yourself!
So SS-520-5 is way smaller than the SLS
partly because it’s only meant to send stuff into low Earth orbit, not deep space.
But at 9.5 meters tall, it’s also much smaller than typical orbital rockets.
And that’s because SS-520-5 is actually a modified suborbital rocket.
Suborbital rockets have enough oomph to get above the Kármán line,
the arbitrary 100 kilometer height many scientists use to define the edge of space.
But they don’t go fast enough to stay in orbit around Earth.
They fall back into the atmosphere as soon as their engines shut off.
The team that built SS-520-5 was on a mission to construct the smallest,
cheapest rocket that could launch a satellite into orbit,
so they started with a tiny suborbital Japanese rocket called the SS-520.
The SS-520 is a special kind of suborbital rocket called a sounding rocket.
The sounding part of the name comes from maritime history,
when sounding meant taking measurements.
And today’s sounding rockets do just that,
hoisting scientific instruments into space for a few minutes to collect data.
But to get their sounding rocket into orbit,
the team needed to make two major modifications.
First, it needed to fly much faster than it was designed to.
Speed is a big part of what separates orbital and suborbital flight.
A suborbital rocket needs to fly 6000 kilometers per hour
to reach a maximum altitude of 125 kilometers.
But to actually achieve a 125 kilometer orbit,
that same rocket would have to fly almost five times faster.
In order to reach those eye-popping speeds, the team added a third set
of rocket engines on top of the two that the regular SS-520 used.
The second modification was that the rocket would need to make a turn
at just the right time.
Sounding rockets typically fly straight up to space
and fall straight back down in a big U-turn shape.
But to get into orbit, SS-520-5 needed to fly straight up into space,
then turn itself horizontally and accelerate.
This was accomplished by adding a reaction control system
between the first and second sets of rocket engines, called stages.
After the first stage had run out of fuel and was ejected,
jets of nitrogen gas would not only help turn the rocket,
but they’d also keep its position stable so it could hit those high speeds.
These two tweaks turned SS-520 into the SS-520-5.
But the most important part was the cargo it carried into orbit.
Nestled in the nose cone of that extra third stage
was a teensy satellite called a CubeSat.
CubeSats are standardized satellites built in dimensions called “U”.
Each U is 10 cm square, and weighs only 1.3 kilograms.
Most CubeSats have 3U sections and weigh 4 kilograms.
They might be tiny, but CubeSats can do all sorts of things in space.
When pointed at the Earth, they can help with everything
from disaster response to climate monitoring.
As part of the Artemis I mission, the Space Launch System
carried ten CubeSats and launched four of them into orbit around the Moon.
Those satellites will look for water and hydrogen
and help create maps of the lunar surface that NASA will use
to plan future landings…like the Artemis III mission.
The CubeSat that SS-520-5 delivered into orbit carried both communications
equipment and five small cameras that took pictures of the Earth for six months.
But why bother with a small rocket that launches individual CubeSats?
Big rockets like the SLS could carry many dozens of CubeSats to space at a time,
especially if humans weren’t also along for the ride.
It’s really handy that CubeSats can carpool with other missions.
But it also limits where the CubeSats can go and when they can launch into space.
Huge rockets like the Space Launch System take years to develop.
If all you want to get to space is a single CubeSat for a short-term research project,
a tiny rocket like the SS-520-5 could be a really tempting future alternative.
If they turn out to be financially viable, that is.
In the meantime, we can hail the SS-520-5 as the king of tiny space rockets.
Huzzah!
We think this tiny record holder is so nifty,
we’ve made an even smaller version you can order today!
The SS-520-5 is our Pin of the Month for all of July.
Put it on your backpack.
Put it on your hat.
Put it on your official SciShow Space Cork Board,
which you can also get by going to DFTBA.com/SciShow.
Thanks for watching!
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