NASA SpaceX Launch

[Fovean]

Wasn't sure where to put this but...

The link below is to NASA TV's youtube live stream of today's Crew Dragon launch. Enjoy!

https://www.youtube.com/watch?v=Aymrnzianf0

Remarkable resemblance to the Galactic Empire o:

 

[Reban]

I'm watching. Its a long time since I've been excited about a manned launch.

Edit: Poop.... scrubbed due to weather

 

[Fovean]

Yeah, totally bummed but it was the right choice IMO. "Safety first" should never be a mere platitude.

Next attempt Sat 30 May, 3:30PM EDT

Would love to hear from folks about "instantaneous launch windows" in general, and can we implement this in a Traveller game somehow? I'm having vague ideas about jump shadows and solar weather while being chased by the local System Patrol...

 

[BRJN]

Would love to hear from folks about "instantaneous launch windows" in general, and can we implement this in a Traveller game somehow? I'm having vague ideas about jump shadows and solar weather while being chased by the local System Patrol...

Apollo 12 launched just ahead of an approaching thunderstorm. After liftoff, lightning struck the exhaust plume, causing the computers and electronic gear to go on the fritz for a moment. (The rocket was overhead and out of the way by that point.) You could narrate something similar if your group is normally into Han Solo -style takeoffs just as The Authorities show up at the landing bay.

"I told you earlier that it was cloudy and raining. The good news is, nobody is crazy enough to chase you through this. The bad news is -rolls dice- the long range scanners say a Space Invaders fleet is approaching."

 

[Grav_Moped]

Yeah, totally bummed but it was the right choice IMO. "Safety first" should never be a mere platitude.

Next attempt Sat 30 May, 3:30PM EDT

Would love to hear from folks about "instantaneous launch windows" in general, and can we implement this in a Traveller game somehow? I'm having vague ideas about jump shadows and solar weather while being chased by the local System Patrol...

The instantaneous launch window was because the ISS is moving at 7.7km/sec and the Crew Dragon has to arrive at exactly where the ISS is going to be when it gets there. There's not enough delta-V available to "chase it down" and then come to a stop when they get there.

The delay until Saturday is because the ISS orbit shifts west by about 22.9 degrees longitude on each pass, and the orbital path won't be over Florida again until Saturday. ISS missions have to launch while the station's orbit passes above the launch site because changing orbital inclination is REALLY costly in terms of delta-V.

 

[Grav_Moped]

From a Traveller perspective, it's almost always a moot point, since ships have basically unlimited maneuver.

It is a big deal for Air/Rafts and other low-TL antigrav vehicles, if you're trying to reach something in orbit with only 0.1G acceleration (after weight neutralization) to play with. (At higher TL, grav vehicles have thrusters rather than grav modules, and thus have better lateral acceleration capability.)

 

[Timerover51]

From a Traveller perspective, it's almost always a moot point, since ships have basically unlimited maneuver.

It is a big deal for Air/Rafts and other low-TL antigrav vehicles, if you're trying to reach something in orbit with only 0.1G acceleration (after weight neutralization) to play with. (At higher TL, grav vehicles have thrusters rather than grav modules, and thus have better lateral acceleration capability.)

Where is that stated?

 

[Xerxeskingofking]

Where is that stated?

I think that's a extrapolation of the Megatraveller thing about grav plates being made to thrust in a given direction and providing reduced thrust off-axis, down to 25% at 90° and only 10% at 180°. so, for a 1G grav plate aimed down (like on air/raft), it would only be able to climb at 0.1G.

 

[whartung]

From a Traveller perspective, it's almost always a moot point, since ships have basically unlimited maneuver.

It is a big deal for Air/Rafts and other low-TL antigrav vehicles, if you're trying to reach something in orbit with only 0.1G acceleration (after weight neutralization) to play with. (At higher TL, grav vehicles have thrusters rather than grav modules, and thus have better lateral acceleration capability.)

They may only have 0.1G to play with, but they have effectively an unlimited amount, so they have plenty of time to make up velocity. And 0.1g net thrust is nothing to sneer at.

It's more efficient (in terms of time), obviously to have a properly plotted launch, but not fatal.

 

[Grav_Moped]

They may only have 0.1G to play with, but they have effectively an unlimited amount, so they have plenty of time to make up velocity. And 0.1g net thrust is nothing to sneer at.

It's more efficient (in terms of time), obviously to have a properly plotted launch, but not fatal.

Yeah. I'm figuring the flight profile to an arbitrary orbit would be to ascend vertically to above most of the atmosphere, travel fast in near-vacuum to get under the orbital track (dropping into the atmosphere to aerobrake once near the starting point), then going up and forward from there.

I think aerobraking to cancel lateral momentum saves time over trying to shift orbital inclination through lateral acceleration, but throwing away the upward vector from the early ascent phase might cancel the time savings.

Just trying to add some "crunch" to the "Air/Raft can reach orbit in [world's size code] hours" rule.

 

[Straybow]

Note: [Alt]0176 [on number pad] = °

 

[Xerxeskingofking]

°

huh, never knew that. thankyou.