
SpaceX Crew Demo-1 Mission [video] - mch82
https://www.spacex.com/webcast
======
primordialsoup
I am an engineer who builds with a computer. And when I see such things as
this, I sometimes spend a minute or so marveling and thinking about the
complexity of building and orchestrating such a launch. In fact, I really
cannot comprehend how something like this can be successfully done, given how
so many things could go wrong. Yes, I understand the idea of redundancy, I
understand gravity, I understand that physics and chemistry goes into this,
but still, the engineer in me wonders how on earth can we make all of this
work together. Really, kudos to spaceX, kudos to NASA, and and kudos to those
who believe in science.

~~~
Gravityloss
Computer engineering is new. We're still at the phase where bridges collapse
and ships sink regularly.

~~~
twtw
Computer engineering is not substantially newer than aerospace engineering.

~~~
mLuby
It's true, they just have different focuses. Aerospace (in general) has traded
huge costs for safety and reliability. Computer engineering (in general) has
traded correctness/reliability for low cost and rapid development.

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jpatokal
Looks like they nailed the launch: first stage recovered and Dragon 2
separated successfully. Congratulations SpaceX!

Docking with the ISS is scheduled ~27 hours from now on Sunday, March 3 at
10:55 UTC (5:55 EST).

[https://www.space.com/how-to-watch-spacex-crew-dragon-
demo-1...](https://www.space.com/how-to-watch-spacex-crew-dragon-
demo-1-mission.html)

~~~
jessriedel
Anyone know why they choose a launch time and trajectory such that the arrival
at ISS is more than a day later? It seems like you could choose to arrive at
the ISS almost immediately after reaching orbital velocity if you wanted.

~~~
simonh
They don’t reach the stations orbital velocity immediately after launch
though. What they do is launch into a lower orbit behind the station. Lower
orbits have a shorter orbital period, so they gradually catch up and raise
their orbit as they get closer.

If the went into a ballistic trajectory directly at the station, there is a
risk of debris from the launch, such as paint flecks, scraps of metal, etc
hitting the station. Also a lower initial target orbit makes various abort
scenarios easier. Then of course another poster has pointed out they need time
to check and validate all the vehicles systems.

Generally in space it’s best to avoid doing anything in a rush if you can
avoid it. In recent years the Russians moved to a 6 hour launch to rendezvous
window which is pretty quick really. This is what made it possible to capture
footage of the launch from the station.

[https://youtu.be/ouBfzCgXHgk](https://youtu.be/ouBfzCgXHgk)

~~~
sandworm101
Technically they do reach the stations velocity. In fact they exceed it. The
lower orbit is slightly faster. Total energy is lower, but they are moving
faster than the station.

A counterintuitive part of spaceflight is that often you have to first
accellerate in order to slow down.

~~~
vermontdevil
Makes sense. Get up to a higher speed and it’s easier to do a controlled slow
down. Than having to speed up after getting into orbit near another orbiting
body.

~~~
JshWright
That's not really it. "Speeding up" and "slowing down" are equally easy (or
hard). They're both acceleration, just in a different direction.

The reason it's going faster is because it's lower. The lower an orbit, the
faster the thing is moving. In order to slow down, you have to accelerate
twice (I'm using the term "accelerate" here to refer to "going faster in the
direction you're already going").

The first acceleration raises the far side of your orbit. You then have to
"climb" up to that new higher orbit. Once there, you accelerate again to raise
the low side of the orbit (otherwise you'd pick up all that speed again then
"falling" back down to the lower altitude).

At the end, you're in a new, higher, orbit, going slower than when you
started.

------
Symmetry
From Eric Berger's twitter[1]

> _If the first stage lands tonight, SpaceX will have successfully landed 35
> of its 69 launches, meaning that MORE THAN HALF of its rocket launches will
> have safely returned._

[1][https://twitter.com/SciGuySpace/status/1101752352317628416](https://twitter.com/SciGuySpace/status/1101752352317628416)

~~~
aboutruby
Same thing happened to NASA, started at 43.6% success rate for 1950s then
85.1% for 1960s, etc. etc.
[https://space.stackexchange.com/questions/1659/what-is-
the-s...](https://space.stackexchange.com/questions/1659/what-is-the-success-
rate-of-nasa-launches)

------
hsrada
"Science is the only news."

([https://www.goodreads.com/quotes/213539-science-is-the-
only-...](https://www.goodreads.com/quotes/213539-science-is-the-only-news-
when-you-scan-a-news))

------
14
This is so exciting! I had not heard this was happening and came to my
favorite site to check out some bed time reading and find this! Awesome

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mhsabbagh
Ah, here I am, setting under the blanket and drinking a cup of tea with lemon,
watching a rocket 9600km away from me that's about to go to space in few
minutes.

What a time to be alive.

~~~
cheese_toasty
Pretty great friday night!

~~~
mhsabbagh
It's Saturday 11AM here, though.

~~~
lostlogin
Saturday night here.

What time zones do rockets use?

~~~
occamschainsaw
UTC is the time zone of space missions usually.

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ramidarigaz
The NASA TV feed seems to be higher quality than youtube (and has identical
content).

[https://www.nasa.gov/multimedia/nasatv/index.html#public](https://www.nasa.gov/multimedia/nasatv/index.html#public)

~~~
azernik
Had same quality issues - then just told YouTube to use 720p instead of auto-
resolution and it got all better.

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cheese_toasty
Man this makes me miss when I was living at UCF - we'd see shuttles taking off
at Kennedy space center from East Orlando

~~~
hoorayimhelping
I grew up in southwest Orlando. We'd go outside during elementary school to
watch the launches, we'd interrupt little league games and football games to
watch the launches. Kids and parents all just found it so magical and amazing.
Those solid rockets were clearly visible even 70 miles away.

~~~
goshx
I am 180+ miles South from the pad and it is visible from here! I love
watching them.

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amayne
I’m at Kennedy Space Center on the causeway across from the launch pad. Just
watched it from approximately 5 miles away. Insane.

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headmelted
Thanks for posting this. I always watch the launches with my kids and I'd
totally forgotten it was this morning.

------
WestCoastJustin
Post Launch Interview w/ Elon Musk & NASA Team Discuss SpaceX Dragon 2 Launch
Success @
[https://www.youtube.com/watch?v=HuXPLtJXd14](https://www.youtube.com/watch?v=HuXPLtJXd14)

------
function_seven
Goosebumps when stage 1 stuck that landing.

Godspeed, Ripley!

~~~
zedgerman
Same here. Watching rockets land from orbit will maybe never get old.

Awesome job to everyone at SpaceX! Godspeed for the rest of the mission!

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sidcool
Everything went well so far. Lift off, stage separation, first stage Landing,
Dragon separation. They have honed these steps over the past several years.
The ISS rendezvous is going to be just as successful. Great going SpaceX/NASA.

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rasikjain
Kudos to the entire team of SpaceX, Nasa and Ripley (dummy) for this mission.
This takes a great amount of co-ordination and integration to make this
complex mission successful. Living in great era of innovation and advancement
in space.

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mch82
Launch window opens at 2:49 a.m. EST, or 7:49 UTC.

~~~
JshWright
It also closes at 2:49 a.m. EST (Falcon 9 launches to the ISS have
instantaneous launch windows).

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smdyc1
Amazing footage. The precision Landing of stage 1 was something I hasn't
expected.

~~~
JshWright
This was actually one of the less precise landings. Generally it's right on
the X. It looks like it may have slid a bit after touchdown.

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slim
tl;dr

no crew onboard

(still a great achievement)

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antimora
[https://www.youtube.com/watch?v=u-SAdjoFVHk](https://www.youtube.com/watch?v=u-SAdjoFVHk)

~~~
gresrun
Official stream:
[https://www.youtube.com/watch?v=2ZL0tbOZYhE](https://www.youtube.com/watch?v=2ZL0tbOZYhE)

~~~
empyrical
If anyone is confused, the posted unofficial link is a rebroadcast of the
Nusantara Satu mission and is not the Crew test.

