Hello Space Fans and welcome to another edition of Space Fan News.
This week, SpaceX completes an important milestone its quest to make rocket launches into Earth
orbit cheaper; astronomers have found a way to have an accelerating universe without dark
energy; and Space Fan News goes to Washington to march for science on April 22nd.
Yesterday, from the historic launch pad 39A at the Kennedy Space Center the SpaceX Corporation
achieved a huge milestone in making access to space cheaper.
For the first time, SpaceX reused one of its rockets to launch a communication satellite
known as SES-10, which will bring high capacity satellite service to Bolivia, Colombia, Ecuador
and Peru.
With yesterday's launch, SpaceX has proven that it can recover, restore and relaunch
a critical component of the Dragon 9 launch vehicle and doing this means that it can get
stuff into orbit cheaper.
The hope is that the more they can do this, the cheaper it will be to put stuff into space.
The entire Dragon 9 rocket isn't reused, only the massive first stage, but if companies
choose to launch their payloads using a refurbished first stage, then SpaceX reports they can
save up to 30 percent of the cost of the launch.
And since the cost to launch a Falcon 9 starts at around $60 million, launching on a used
rocket could start at around $40 million.
Yesterday's launch used the second rocket ever recovered by SpaceX; it was the same
vehicle used for CRS-8, the company's eighth cargo resupply mission to the International
Space Station launched almost a full year ago on April 8th, 2016.
Then they recovered it on the drone ship named Of Course I Still Love You, and started getting
it ready to use again.
It took SpaceX about 4 months to get it ready again for another launch.
As you can imagine, this process isn't easy, each component has to be inspected and refurbished
to be used again, but that's way cheaper than building them from scratch each time and
then throwing them away.
Which is the path the SLS or Space Launch System is taking.
You may be wondering why in this day and age why we would take such a wasteful approach
to getting into orbit?
That's a good question and the answer has to do with different design objectives.
Setting aside a minute the fact that Congress told NASA to build the SLS this way, there
are other reasons why recovering the SLS is impractical.
First off, the SLS is a much bigger rocket and designed to get much bigger payloads into
orbit.
It's designed to carry 5-10 times more payload.
Further, the Solid Rocket Boosters used by SLS are relatively cheap to rebuild each time
making it somewhat unnecessary.
There's not a lot left of the SRB's once they are spent to actually recover which is
why NASA never bothered with the ones on the Space Shutlle.
Then there's the SLS second stage.
It is a huge, orange tank full of cryofuels and four advanced engines.
And while it would be worth it to get these engines back, it's not really possible.
The tank itself is quite soft, mostly made of foam with a thin aluminum lining.
What's more, it carries a lot of fuel, meaning a lot of delta-V and that means it reaches
a very high speed and very high altitude.
To get it back means it needs to lose that speed and altitude.
This is quite opposite to Falcon 9's recoverable first stage, which barely reaches barely 1.5km/s
(out of about 8 km/s or so to reach orbit) and it only very shortly peeks out above the
atmosphere.
The Falcon 9 can brake and descend at reasonable, survivable speed, without burning up and without
spending excessive amounts of fuel on braking, to avoid burning up.
It is the second, non-recoverable stage that carries most of the responsibility for reaching
orbital speed.
So it's not really fair to compare the two launch designs.
While SLS will be more expensive and wasteful, it's primary purpose isn't to make space
cheap like the Falcon 9 is, it is an explorer rocket that will help NASA regain a human
launch capability and will serve as a backbone for any future human Moon and Mars missions.
Yesterday's launch was a huge step forward in commercializing space and I was very happy
to see everything go off without a hitch, the launch was spectacular, a few minutes
later the first stage landed on Of Course I Still Love You, and the SES-10 satellite
was successfully deployed.
The satellite SES company said that they did indeed get a discount on the launch but non-disclosure
agreements prevent them from giving exact numbers.
But I think more than the discount, the company really wanted to be the first one to use a
refurbished SpaceX rocket.
Next astronomers have worked out a way to have an accelerating, expanding universe without
dark energy.
According to a Hungarian-American team, they believe that standard models of the universe
fail to take into account of its changing structure, and claim that once you do that the need for
dark energy disappears.
We've known for about 20 years now that the universe was accelerating as it expands
and this cosmic surprise has had cosmologists scrambling ever since to try and explain why
it's doing that.
To explain the energy associated with the force that is causing this expansion, astronomers
reasoned that almost 70 percent of the universe must consist of whatever that is - and they
called it dark energy.
We've also known for quite a while that there's this stuff out there, called dark
matter that we seem to talk about every episode, which is out there permeating about 25 percent
or so of the cosmos.
But there are some researchers out there, led by a PhD Student at a university in Hungary,
which I'm not gonna pronounce because I'll just mess it up, who are questioning that
dark energy is really required to accelerate the universe.
These guys are arguing that the data points we have for measuring the acceleration of
the universe - which consist of observations of Type-1a supernovae throughout the sky - only
provide enough information to give us an average acceleration.
This average is throughout the whole universe and it could be, in fact it is probable, that
the universe is expanding at different rates in different areas.
The current theories, the team argues, ignore the intricate structure of the large scale
universe.
The mathematics that describe the expansion of the universe is embedded in equations from
Einstein's Theory of General Relativity and are amazingly complex.
Dr László Dobos, a co-author of the paper, explains that, "We know from very precise
supernova observations that the universe is accelerating, but at the same time we rely
on coarse approximations to Einstein's equations which may introduce serious side-effects,
such as the need for dark energy, in the models designed to fit the observational data."
When we look at the large scale structure of the universe, we see a cosmic web of galaxies
that follow huge tendrils throughout space time and normal and dark matter appear to
fill the universe with a foam-like structure, where galaxies are located on the thin walls
between bubbles, and are grouped into superclusters.
The insides of the bubbles by comparison are almost empty of both kinds of matter.
Using a computer simulation to model the effect of gravity on the distribution of millions
of particles of dark matter, the scientists reconstructed the evolution of the universe,
including the early clumping of matter, and the formation of large scale structure.
I always love saying things like 'reconstructing the evolution of the universe'.
Golden age folks!
Unlike most simulations that approximate a smoothly expanding universe, taking the structure
into account led to a model where different regions of the cosmos expand at different
rates.
The average expansion rate though is consistent with present observations, which suggest an
overall acceleration.
Which is what we see, so that's good!
Dr. Dobos concludes by saying, "The theory of general relativity is fundamental in understanding
the way the universe evolves.
We do not question its validity; we question the validity of the approximate solutions.
Our findings rely on a mathematical conjecture which permits the differential expansion of
space, consistent with general relativity, and they show how the formation of complex
structures of matter affects the expansion.
These issues were previously swept under the rug but taking them into account can explain
the acceleration without the need for dark energy."
If this finding is upheld, it could have a significant impact on models of the universe
and the direction of research in physics.
For the past 20 years, astronomers and theoretical physicists have speculated on the nature of
dark energy, but it still remains an unsolved mystery.
Nobody has any idea what this stuff is.
With this new model, these guys expect at the very least to start a lively debate.
I love science.
Finally, like this shirt?
I'm going to wear it later this month when I go to the March for Science in Washington
D.C. on April 22nd.
I also made this Deep Astronomy Hoodie in case it gets cold.
I try to keep politics out of my online life, but as many of you who have been following
me for a while know that I am passionate about improving science education in, not just the
United States, but the entire world.
I concentrate on the U.S. though because it needs it the most, we are among the worst
in the world when it comes to science literacy and I simply can't live with that.
I fervently believe that a person who has a modest education in science has an advantage
in life and is better able to make better decisions, both politically and in daily life.
It seems to me that science in my country continually takes a back seat to almost everything
else, we prioritize the wrong things, like jobs in coal country over the health of our
planet.
It makes no sense to me to burn more coal at the expense of having a home planet to
live on.
And the jobs thing doesn't cut it with me.
Don't tell me, 'well those coal miners are out of jobs and that's not fair'.
No, it's not fair, but reviving a dangerous career path fraught with environmental disasters
everywhere isn't the solution.
The solution, as I see it, is to educate people, like those miners, to do other jobs, ones
that probably pay more.
When I hear about the lack of jobs in I shake my head.
We have companies scrambling to fill jobs all over the place.
An education in science gives everyone a leg up and allows people access to more than just
one kind of job.
The days of pulling a lever all day on a factory floor are long gone, robots do that now.
What's needed are people to build and repair the robots, program CNC milling machines,
operate complicated manufacturing machinery, work with sophisticated computer controlled,
well everything, repair computerized appliances, all kinds of jobs
are not being filled because there aren't any qualified
candidates to do them.
And if you care about energy jobs, there are solar and wind power installations and renewable energy.
There are lots and lots of jobs here, the thing is, you have to know things.
You need an education, one that is heavy in the sciences.
While I do the best I can with my modest YouTube channel, there is a lot more I can do and
that's why I'm going to the March.
I've never done anything overtly political before but I feel pretty strongly about this.
I remember that Carl Sagan was politically active, I actually saw him once in the 1980's
in Colorado at a protest at the Rocky Flats nuclear weapon plant.
I'm no Carl Sagan, but, well, every little bit helps.
I'll hopefully have some remote live streaming equipment with me when I go so I'll try
to live stream it that day but I'll keep you posted on the progress of that.
If you want to talk more about this and the stuff we talked about a couple of weeks ago
about expanding SFN, please join me for another Space Fan News Live event next Wednesday at
3pm ET.
The link is in the description box below and if you click on the little bell icon on the
watch page, you'll get a reminder.
That's it for this week Space Fans.
This show is supported by SFN Patreon Patrons whose contributions make sure you see this
every Friday, so thank you very much.
Thanks to all of you for watching and as always,
Keep Looking Up!
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