When we send anything to space, we have to pay an enormous amount of money.
That’s because you need to push satellites, water, astronauts up and out of the Earth’s
gravity well.
Whether you’re just going to orbit, or heading to the Moon, or out into deep space, it makes
the most sense to build your structures in space, out of material that you got from space.
Obviously, that’s easier said than done.
But today I want to talk about some interesting projects that have already demonstrated that
it’s possible, and what the future might hold for building equipment and structures
in space.
We keep joking about the launch date of James Webb getting pushed back further and further
into the future.
Right now I think we’re looking at a launch date of the year 3000, but I’ll keep you
updated if that changes.
A big part of why this is so expensive and time consuming is that you’ve got to build
a huge, complicated space telescope down here on the ground, and then launch it to space
where it can begin operations.
Your space telescope needs to be able to fold up within the relatively small fairing of
the launch rocket.
Then it needs to unfold like origami to its full size and shape once it space.
The telescope and its electronics - the very definition of fragile - need to be able to
survive transportation and testing here in Earth gravity and then handle the shaking
and acceleration of launch.
Every single aspect of the mission needs to go perfectly.
And if any part fails, there’s no way to fix it after.
Nearly billion dollars can be wasted because a single hinge doesn’t work properly.
No, I can’t even imagine it.
But what if you could construct your mission in space?
Where it never needs to experience the gravity of Earth pulling it down?
Where the size of your telescope or station isn’t limited by the launch fairing of your
rocket?
The quick answer, of course, is that we’ve already tried construction in space: the International
Space Station.
At last count, 32 separate modules, trusses, solar panels and Canadarms have been attached
to the space station, as well as the various cargo and escape capsules on board.
The first module, Zarya, was launched in 1998, and over the last 20+ years, another 40 assembly
flights using Proton, Soyuz, space shuttles and Dragon capsules have launched delivering
additional hardware.
In fact, there are still another few Russian pieces in construction, which should launch
in the next few years.
And all this time, it’s been continuously inhabited by astronauts from around the world.
At this point, the ISS has a total internal volume of 1,000 cubic meters and a mass of
420 metric tonnes, and it’s one of the most complicated things ever built by humanity.
There’s definitely an argument to be made about whether or not this was the best way
to build a space station.
Whether it makes more sense to launch a single inflatable space habitat in one launch.
Or whether building modules on the ground and then assembling them in space makes more
sense.
But it’s hard to argue against the tremendous success as an international collaboration.
Space is hard, and working on it together will probably be the only way to make significant
progress.
As work on the International Space Station is winding down, NASA is gearing up to build
its next space-based station: the Deep Space Gateway.
The final configuration is still getting worked out, but it’s expected to be about 6 modules
connected together in a cis-lunar orbit that would serve as a launch point for human missions
down to the Moon and off into deep space, and on to Mars.
It’ll require more powerful rockets capable of carrying modules to such a high orbit,
and better shielding to protect against the increased radiation outside the Earth’s
protective Van Allen Belts.
But the project is essentially the same.
Build the modules down here on Earth, launch them to space and then have astronauts bolt
them all together.
And once again, it’ll probably be an international collaboration, bringing together modules from
many different nations.
But what if we didn’t use humans to build our structures in space?
What if we had robots carry the raw materials and then build gigantic space telescopes,
communications arrays and space station modules on their own in space?
We’ll get to that in a second, but first I’d like to thank:
Ken Wolfe
Claudio Bottaccini George Palmer
And the rest of our 800 patrons for their generous support.
They contribute so that you can see these videos, and we can make them freely available
to anyone who wants to learn about space.
Join our community at patreon.com/universetoday and get in on the action.
So what about actual construction from raw materials, in space?
A company called Tethers Unlimited is exploring this idea with their SpiderFab architecture.
Instead of building and testing your telescope, space station, etc down here on Earth, SpiderFab
carries the bare minimum material to space and then builds as much as possible right
there in place.
Once you construct your project in space, you’re only limited by the amount of raw
materials at your disposal.
Let me give you a concrete example.
In a previous video, we talked about the Starshade coronograph, a flower-shaped spacecraft that
blocks the light from a star, revealing the faint light of the planets orbiting around
it.
With current launch vehicles, the largest possible Starshade would be on the order of
about 62 meters across, with a mass of 1,495 kilograms in a launch fairing of 7.7 meters
by 4.5 meters..
The deployment phase would be incredibly tricky, with every strut and fold working perfectly
to deploy the entire shade.
But if you launched a SpiderFab with the raw materials it needs to build a starshade, it
could construct one 124 meters across with the same launch mass of 1,495 kilograms, but
with 1/30th the launch volume.
A much larger Starshade would allow telescopes to detect planets twice as close to their
parent star, multiplying the total number of planets by about 8.
Another example.
A large aperture radio dish, for space science or deep space communications.
NASA communicates with its spacecraft using the Deep Space Network.
They have a range of telescopes across the Earth, but the biggest are the 70-meter antennae,
capable of communicating with the Voyager spacecraft 20 light-hours away, as well as
New Horizons, which is out exploring the Kuiper Belt.
At a certain point, a fully steerable radio dish is limited by what it takes to fight
gravity down here on Earth.
Not to mention the fact that the Earth itself is blocking half the sky, all the time.
Out in space, though, things get pretty interesting.
According to Tethers Unlimited, they could build a 300 meter antenna - an Arecibo radio
telescope in orbit - with only 2 cubic meters of raw materials and a mass of 1,500 kg. 50
days after their SpiderFab got to work, you could have a completed space-based antenna.
Want to go bigger?
A Falcon Heavy could probably get you a 1000 meter antenna.
How does it actually work?
Tethers Unlimited has a manufacturing robot they call the Trusselator.
It uses an on-board 3D printer to construct a continuous 5 centimeter triangular truss.
These trusses can then be assembled together to form larger and larger structures.
During a recent test down here in Earth gravity, their Trusselator prototype was able to build
a 10-meter long truss that weighed only 340 grams.
It took 3 hours to build, with the truss growing at about 5 centimeters per minute.
As a next stage proof of concept, Tethers Unlimited would like to launch a pair of cubesats
side by side, and then manufacture a 50-meter truss, separating them in space.
This proof of concept could then do science, like very long baseline array astronomy, or
help measure the Earth’s ionosphere.
But let’s get to the best part.
The Mother of All Telescopes.
With a single launch, Tethers Unlimited has calculated they could build a single truss
7 kilometers long, 100 mm wide out of raw material.
This could turn into a hexagonal space platform 37 meters on a side, or a ring that’s 555
meters across.
That would make for a very big telescope.
Reusable rockets are lowering the launch costs for getting missions into space.
But I think the true revolution will begin when we learn to master space-based construction
methods.
Not to mention the exponential increase that will happen when we can acquire our raw materials
from space itself.
Then we will truly become a space-faring civilization.
What do you think?
Let me know your thoughts in the comments.
Once a week I gather up all my space news into a single email newsletter and send it
out.
It’s got pictures, brief highlights about the story, and links so you can find out more.
Go to universetoday.com/newsletter to sign up.
Did you know that all of my videos are also available in a handy audio podcast format,
so you can have the latest episodes show up right on your audio device.
Go to universetoday.com/audio, or search for Universe Today on iTunes, Spotify or wherever
you get your podcasts.
I’ll put a link in the shownotes.
And finally, here’s a playlist.