It might have been thirty years ago, I heard this story, maybe from one of my college professors. Basically, Edison tried over a thousand materials as filaments for his light bulb before he found one that worked. And a reporter asked him what it felt like to fail a thousand times, and Edison said he never failed once. He just found over a thousand things that didn’t work. I have no idea how true that story is, but it is a perfect example of how science is supposed to work.
I was thinking
about this after the eighth example of how Starship didn’t work. I do believe it is possible to build a fully
reuseable rocket. If we have the
technology and understanding to do it now, remains to be seen. I’m not dismissing Starship as a total failure,
but I do agree that it is not living up to the hype. And I increasingly feel that it likely needs
a redesign.
As I said, I was
thinking about all this after Flight 8, and I realized that the booster seems
to work. It’s not launching and landing
perfectly, but how many attempts did it take to land the Falcon 9 first
stage? A couple months ago, I wrote up a
post with my Thoughts on Starship, and I had a section on how I would have done
things differently if I had been in charge, and one of them was to start with
an expendable second stage. That way you
could start putting stuff into orbit, while also running experiments on reentry
to get some data before trying to build a reusable upper stage. And I started wondering what kind of missions
could be launched with a Starship Booster and an expendable second stage. Here are the three ideas I came up with.
A space station
Decades ago, I
heard about an idea to make some changes to the Space Shuttle so that the
External Tank – normally left to burn up in the atmosphere – would be left in
orbit. Crews could then go to it and
turn it into a space station. I started
thinking about doing that with an expendable second stage, but the more I
thought about it, the more issues came up.
For example, since rockets are designed to be as light as possible and
aren’t meant to spend long periods of time in space, they don’t have shielding
for micrometeors. So to shield a second
stage turned space station, you’d either have to have some shielding that would
go on the outside once it is in orbit – which I image would be a huge pain – or
you’d build it with the added shielding.
But if there’s more shielding, you’d have smaller fuel tanks and part of
the idea for this space station stage would be to have it built alongside the
reuseable stages to minimize costs, but needing smaller fuel tanks would mean a
different assembly line. And then
there’s the issue of hatches. Fuel tanks
have holes in them for the fuel to get in and go out, but they’re not two
meters in diameter to allow a human with cargo to get through. So you’d either have to spend all the time
and effort into building tanks with such large hatches that don’t leak during
launch, or just use normal tanks and cut the hatches into them once the stage
is in orbit. But how do you cut through
a fuel tank in orbit in a manner that doesn’t create problems, such as igniting
leftover fuel, or filling the space with metal filings? And then you get into stuff like power
cables. The ideal thing would be to
build this station stage with all the power cables and ventilation ducts
outside the fuel tanks. But then you
either need premade access points for these, or there would be additional spots
in the tank that need cut. And what
about the space inside the tank? Do you
leave it one big open space, or do you put a bunch of anchor points so that you
can attach wall pieces to make rooms?
It seems for every
issue you can either solve it on the ground, meaning a lot of work to make sure
you don’t make things worse like making the fuel tanks too weak by putting a
bunch of hatches in them, or you solve them in orbit, meaning a lot of work
because you have to be extra, extra, extra, extra certain things are safe. In the end, I’d say it would probably be
faster and safer to launch a Starship Booster with an expendable second stage
that just puts as big as possible modules into orbit. Link a couple of these up, and you have a
space station.
Space junk remover
craft
I have … an
interest, I guess, about removing space junk.
A few years ago, I even wrote about A Space Junk Prize I would start if
I had billions of dollars I didn’t know what else to do with. So I definitely wondered what space junk
remover thing could be launched with a Starship with expendable second stage.
What I came up
with, looks a bit like the ship from You Only Live Twice, or Rocket Lab’s
Neutron. Basically, the fairing wouldn’t
be jettisoned, but would remain attached to the craft for the whole
mission. Once in orbit, the fairing
would open, but other than some cubesats, there probably wouldn’t be a
satellite. With the extra mass of the
fairings – as large as they can make – there wouldn’t be much extra mass for a
satellite. With the fairings open, the
craft would approach a dead satellite, or maybe some upper stage left in
orbit. The craft would slowly close the
distance, and then some robotic hands would grab hold of the space junk. Then the fairings would close and lock shut. The craft would then deorbit to burn up in
the atmosphere. The reasons for the
fairings, is that there could be paint flecks or other small pieces that could
come off during the deorbit, and the fairings would stop them from getting
loose. Also, most satellites and upper
stages aren’t designed to be grappled by something, so these robotic hands
would have to take hold of thrusters, or an antenna or something that may not
be that strong, especially after decades in space. The deorbit burn would be very gentle, but
there’s still the possibility the junk could break loose, and hopefully the
fairing would be able to hold everything in.
The real idea of
this system, is that after testing it a few times in low Earth orbit, you could
send one out to geosynchronous orbit to grab hold of a defunct satellite. But instead of bringing it all the way back
down to burn up in the atmosphere, the craft would just go out to a graveyard
orbit. This would open up a slot for a
new satellite.
Of course, satellites
can fit in the fairing of a small rocket to launch because the solar panels and
antenna are usually folded up. But once
they unfurl in space, there might not be a way to build a fairing large enough
to contain them. So while there are some
situations where this space junk remover craft would be great, to really clean
up the orbits around Earth will require other things.
Atmospheric drag
test
I did a series of
posts about space missions I’d fund if I had the money to burn, and in one I
discussed an idea of putting a bunch of cubesats into very low orbits so they
can observe how things like paint flecks interact with the tenuous upper
atmosphere. This would be an extension
of that.
The idea is to launch,
I don’t know, a thousand cubesats on one mission. The most basic idea, is if you had two cubesats
that had the same mass, but one was more aerodynamic than the other, and you
released them in the same orbit, would the less aerodynamic one deorbit
sooner. The knee-jerk answer is yes, but
how much sooner? That’s what this
mission would test. The way you test it,
is you have six or seven designs for cubesats, and you build a hundred or so of
each. You then release ten of each at an
altitude where they’d likely deorbit and burn up in about a month. And then you release ten more a few
kilometers higher, and so on until the last batch will likely stay in orbit for
about a year. And then you monitor when they
deorbit. And I’m sure there would be
other cubesats that could hitch a ride to such orbits.
The point of this
mission would be to get some real-world data on how things behave as they’re
deorbiting. One possibility – either a
mission launched on a smaller rocket, but it could also be part of this mission
– would be to have a bunch of dummy cubesats set to immediately deorbit. These dummy cubesats wouldn’t have batteries
or anything dense or hazardous. But they
might have containers of various substances that burn in distinct colors. These would be set to deorbit and burn up somewhere
over, say, the continental US. I’m sure
people have seen cubesats burning up in the atmosphere, but nobody knew it was
happening and so had instruments set up to record it. Besides the science, I’d love to see ten
bright meteors within a few minutes.
***
So those are my
ideas. Are they the greatest of
ideas? No. But if they keep blowing up Starships, they
may need some backup ideas for the booster.
Just saying.
