SpaceX Launching Astronauts into Space Today

[Michael in ABQ]

Edit: Original launch window on the 27th was scrubbed due to weather, backup launch window today, May 30th at 3:22 EDT. See below for details, current live feed: https://www.youtube.com/watch?v=bIZsnKGV8TE

In less than an hour US astronauts will fly into space again on an American spacecraft from American soil.

The NASA YouTube live feed has over 900,000 viewers: https://www.youtube.com/watch?v=Aymrnzianf0

The SpaceX YouTube live feed has almost 700,000 viewers: https://www.youtube.com/watch?v=Aymrnzianf0

Hopefully the weather clears and they can launch. This will be a historic day, the first commercial spacecraft to take astronauts into orbit.

Watch history unfold on Wednesday, May 27, as NASA and SpaceX launch astronauts Robert Behnken and Douglas Hurley to the International Space Station. This mission marks the first time since the retirement of the space shuttle in 2011 that humans will fly to the space station from U.S. soil.

Tune in starting at 12:15 p.m. EDT as NASA and SpaceX provide joint, live coverage from launch to arrival at the space station. Teams are targeting 4:33 p.m. EDT for the launch of the SpaceX Crew Dragon spacecraft atop a Falcon 9 rocket from historic Launch Complex 39A at NASA’s Kennedy Space Center in Florida. The Crew Dragon is scheduled to dock to the space station at 11:29 a.m. Thursday, May 28.

Learn more about the mission: https://www.nasa.gov/launchamerica/

[Michael in ABQ]

Launch was scrubbed for weather at T minus 16 minutes. Next launch window is on May 30th at 3:22 p.m. EDT, or 19:22 UTC, and on Sunday, May 31st at 3:00 p.m. EDT, or 19:00 UTC.

[secondcor521]

One of the things I thought was interesting in the commentary today is that it is an instantaneous launch window.  I assume that is because it is a mission to the ISS, so they need to coordinate the launch with the ISS location.  I think they said Saturday's launch window is also instantaneous.

Since the ISS orbits every 90 minutes or so (as most LEO satellites seem to, I'm guessing as a consequence of orbital velocity), I'm curious why they don't have a repetitive instantaneous launch window.  Like if it doesn't work Saturday at 3:22pm, why won't it work at about 5:02pm?

Having asked that, I think it's because as the ISS orbits in LEO, the location of the Earth underneath it shifts over time, so there are only particular orbits that are "close enough" to Florida for the paths to work.  Saturday at 3:22 pm must be an approximately integral number of orbits of the ISS relative to today's launch time.  Let's see, that's just under 71 hours, which is 4,260 minutes, subtracting the 11 minutes makes it 4,249 minutes.  Dividing by 90 minutes per orbit, that works out to 47.something orbits, which means it's probably 47 orbits and the ISS actually orbits every 90.4 minutes or so.

I'm glad I wasn't the one doing the math for all this; it's obviously well beyond my pay grade.

I'm still curious why the constraints work such that the next launch window is 3 days away but the one after that is only one day beyond.  Hmm.

[js82]

I'm still curious why the constraints work such that the next launch window is 3 days away but the one after that is only one day beyond.  Hmm.

Unless the ISS/a satellite is orbiting directly over the equator, its not just changing in terms of longitude, but in terms latitude relative to the earth underneath it, thus it takes a certain number of cycles to approach the same point above the earth.  It's also(in theory) possible for a rocket to intercept the ISS from 2 different directions, depending on when in the orbital cycle the rocket is launched.  But in practice they leverage the velocity of the earth's rotation to reduce the amount of energy required for the rocket to reach orbital velocity.

This is a good visualization:

https://www.youtube.com/watch?v=foQpkvW_N2U

[maizefolk]

Was excited to watch this and am more excited at the thought of getting to watch it on Saturday when I won't have to also pretend to be participating in two different zoom meetings.

[Michael in ABQ]

Link to launch live feed from SpaceX: https://www.youtube.com/watch?v=bIZsnKGV8TE

After standing down from launch on Wednesday May 27, SpaceX is now targeting Saturday, May 30 for Falcon 9’s launch of Crew Dragon’s second demonstration (Demo-2) mission from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida. This test flight with NASA astronauts Bob Behnken and Doug Hurley on board the Dragon spacecraft will return human spaceflight to the United States.

The instantaneous launch window opens at 3:22 p.m. EDT, or 19:22 UTC, with a backup instantaneous launch opportunity available on Sunday, May 31 at 3:00 p.m. EDT, or 19:00 UTC. Tune in here to watch the launch webcast. Coverage will begin about 4 hours before liftoff.

Demo-2 is the final major test for SpaceX’s human spaceflight system to be certified by NASA for operational crew missions to and from the International Space Station. SpaceX is returning human spaceflight to the United States with one of the safest, most advanced systems ever built, and NASA’s Commercial Crew Program is a turning point for America’s future in space exploration that lays the groundwork for future missions to the Moon, Mars, and beyond.

[YYK]

T-15! Exciting

[YYK]

I've not seen the inside of the capsule before, so it's interesting to see how automated everything is these days. The capsule almost looks like a barebones mock-up with how empty it is inside and just the control screens in front.

[lemanfan]

I'm watching, and so are my friends in this saturday evening Zoom meeting... :)

[lemanfan]

I've not seen the inside of the capsule before, so it's interesting to see how automated everything is these days. The capsule almost looks like a barebones mock-up with how empty it is inside and just the control screens in front.

I'm note quite sure I like touch screens in this kind of environment.

[maizefolk]

I've been watching since about 30 minutes before the launch window. So much nicer to be able to have undivided attention.

[YYK]

GO!!!

[lemanfan]

Yeeee-haw!

[Michael in ABQ]

Success!

Astronauts in orbit and the first stage landed successfully back on the drone ship in the Atlantic. Perfect launch.

[YYK]

Stuck the landing too. That's never not exciting.

[maizefolk]

Yes!!!

[marty998]

Amazing to see. Well done to all the scientists and engineers involved for launching safely.

[Mr. Green]

I Iove all the camera views SpaceX has and the metrics visualization they use to show where the rocket is in the launch timeline. It's everything I would imagine a launch would be in 2020 with all the tech we have. And the controlled landing just never gets old.

[Paul der Krake]

I Iove all the camera views SpaceX has and the metrics visualization they use to show where the rocket is in the launch timeline. It's everything I would imagine a launch would be in 2020 with all the tech we have. And the controlled landing just never gets old.

When they show it...

[YYK]

I Iove all the camera views SpaceX has and the metrics visualization they use to show where the rocket is in the launch timeline. It's everything I would imagine a launch would be in 2020 with all the tech we have. And the controlled landing just never gets old.

When they show it...

A conspiratorial person might suggest that the feed was intentionally cut as a precaution in case the landing failed, forestalling negative press right after the Starship proto blew up. But I think it's more likely that the feed just cut off because the antenna was jarred by a rocket slamming into the ship.

[maizefolk]

The feed seems to drop out at least two out of every three times they use the drone ship (rather than returning to the launch site).

[mrmoonymartian]

I Iove all the camera views SpaceX has and the metrics visualization they use to show where the rocket is in the launch timeline. It's everything I would imagine a launch would be in 2020 with all the tech we have. And the controlled landing just never gets old.

When they show it...

A conspiratorial person might suggest that the feed was intentionally cut as a precaution in case the landing failed, forestalling negative press right after the Starship proto blew up. But I think it's more likely that the feed just cut off because the antenna was jarred by a rocket slamming into the ship.

The controlled landings were faked. It was all done in a studio on Earth using slow motion and special lighting.

[YYK]

The controlled landings were faked. It was all done in a studio on Earth using slow motion and special lighting.

I'll buy it. The shots of the round "earth" we saw on the feed were obviously bad CGI too.

[Arbitrage]

One of the things I thought was interesting in the commentary today is that it is an instantaneous launch window.  I assume that is because it is a mission to the ISS, so they need to coordinate the launch with the ISS location.  I think they said Saturday's launch window is also instantaneous.

The Falcon 9 launch system is largely designed for instantaneous launch windows.  It's not just their ISS missions, it's basically every mission they fly (it might be every mission now; it's been a couple of years for me since following it that closely).

[mrmoonymartian]

One of the things I thought was interesting in the commentary today is that it is an instantaneous launch window.  I assume that is because it is a mission to the ISS, so they need to coordinate the launch with the ISS location.  I think they said Saturday's launch window is also instantaneous.

Reminds me of this...

https://xkcd.com/1834/

[Wrenchturner]

I Iove all the camera views SpaceX has and the metrics visualization they use to show where the rocket is in the launch timeline. It's everything I would imagine a launch would be in 2020 with all the tech we have. And the controlled landing just never gets old.

I really enjoyed the cameras and production too.  The capsule looked downright comfortable!  Great to see something remarkable like this in such trying times.

[maizefolk]

The capsule looked downright comfortable!  Great to see something remarkable like this in such trying times.

Really drives home that before this Dragon launch the most recent US spaceship rated to carry humans was designed and build in 1982 (the space shuttle) and the only spaceship anywhere in the world that still carried humans to space (Soyez) was designed in the the 1960s.

Our non-space technology has come a long way in the last half century.

[markbike528CBX]

I'm not sure why the launch window was instantaneous. 
I do know that SpaceX can't do long (hours) launch windows, since they use chilled propellants, unlike others who can just top up tanks during a long hold.

I've seen one of the few previous instantaneous launch window shots, Einstein Gravity B Probe.   https://einstein.stanford.edu/MISSION/mission3.html
This was extra cool, because I was on night shift at a job nearby, and I had to get back to sleep.
Having an instantaneous launch window meant a scrub versus a delay.  A delay or long hold might have seen me see the launch in the rear view window as I reluctantly drove away.
It did scrub once, but I knew 23hours 56 minutes later, I'd be able to try again and still be back in time to sleep.

I've seen and heard real (commercial) rockets tested, but they were only ~1lbs thrust.

Disclosure: Former rocket scientist (chemist).  I still have my paystubs from Rocket Research in Redmond WA to prove it, as sometimes that becomes necessary :-)
It is now a division of Aerojet  https://www.rocket.com/space/space-power-propulsion/monopropellant-rocket-engines  .  The rocket shown on the top of the linked page is small, note the wiring (size similar to very small usb cable wires) and the engine bell outlet is 1.3" diameter.  Edit, the one shown is _not_ the smallest as it has 5 lb. thrust.  The smallest is 0.02lbs thrust.

Real Disclosure: just PTF