Poll

Given the weather, do you think the launch will happen today?

Yes
47 (35.3%)
No
86 (64.7%)

Total Members Voted: 133

Voting closed: 05/28/2020 07:21 pm


Author Topic: SpaceX Falcon 9 / Dragon 2 : SpX-DM2 : May 27, 2020 : DISCUSSION  (Read 366506 times)

Offline Yazata

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Whichever The case, as you said, NASA convinced the Russians that the risk was acceptable and DM-1 flew a successful mission. The NASA rep said today that SpaceX made a modification post-DM-1 that eliminated the issue entirely.

I seem to recall reading that the Russians had their cosmonauts retreat to the Russian modules on the far side of the Station when DM-1 docked.

Online harrystranger

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Planet imagery showing Falcon 9 and Crew Dragon on the pad. You can see the crew access arm reaching over to F9.
https://twitter.com/HarryStrangerPG/status/1264005642185916416?s
Contains modified Planet imagery 2020

Online Vettedrmr

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I wasn’t sure myself, so I did some searching and found a quote from Gerstenmaier in the DM-1 FRR that said, “That's the basic concern the Russians brought up, why isn't there a separate system or separate box to go provide this backup capability? We think we have sufficient rationale for that." Whichever The case, as you said, NASA convinced the Russians that the risk was acceptable and DM-1 flew a successful mission. The NASA rep said today that SpaceX made a modification post-DM-1 that eliminated the issue entirely.

Yeah, that definitely perked my ears up.  I would love to learn what they did.

Have a good one,
Mike
Aviation/space enthusiast, retired control system SW engineer, doesn't know anything!

Whichever The case, as you said, NASA convinced the Russians that the risk was acceptable and DM-1 flew a successful mission. The NASA rep said today that SpaceX made a modification post-DM-1 that eliminated the issue entirely.

I seem to recall reading that the Russians had their cosmonauts retreat to the Russian modules on the far side of the Station when DM-1 docked.

I remember they said they were going too but at least one of the Russian's was there with the American and Canadian astronauts during docking. 
 

Online kdhilliard

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If you like podcasts - today’s release has a flight director explaining the details not only of the mission, but how the separate mission controls will work together.

https://overcast.fm/+Pjd9-HXeE
Thanks rdale!  What a great episode!

It starts with a lighthearted, 10 minute interview with the astronauts and is followed by a one hour twenty minute, dense, in-depth discussion with Zebulon Scoville, the NASA Lead Flight Director for DM-2, who led the development of the Crew Dragon flight rules.  There's tons of interesting information in there.

Direct link to that May 22, 2020 Houston We Have a Podcast episode: SpaceX Demo-2
* Transcript on same page
* Right click on "Listen Now" to download.
* Second portion starts at 13:50 with a short introduction of DM-2 and lead-in to the FD Scoville interview which starts at 15:40.

The initial astronaut interview has a bit of info which touches on the "pilot jocks" discussion four pages back, though not specifically explaining why they didn't arrive in a T-38.  Bob Behnken is a flight test engineer, not a test pilot like Doug Hurley is, and they have spent a lot of time together in a T-38.  Doug:
Quote
based on my experience as an astronaut, the Air Force flight test engineers, which is -- you know, Bob is one of those.  I was fortunate enough to fly with Rex Walheim on another flight.  And those guys just bring so much to the table from an astronaut perspective. They, in general, make the best astronauts that I've seen in my 19 plus years here.  And so that program within the Air Force is a tough one to beat as far as getting somebody ready to fly a spaceship. ... You know, Bob is just one of those guys that is -- he's as competent, as smart, dependable.  Whether it was in an airplane, you know, Bob and I probably have a thousand hours together in an airplane.  So just backing me up in the front seat many times or helping make a decision, a weather decision or another decision.

Offline CorvusCorax

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We know the initial orbit of Dragon is 190x205km but does anyone know (or can calculate from launchtime, launch timeline and ISS orbit) the intial phasing angle between dragon and the ISS? (just after dragon separation)

I wrote a userscript mod of the SpaceX ISS docking simulator that you can install in the webbrowser which will now let's you control dragon manually during phasing and rendezvous as well as docking (as opposed to only docking with the unmodified sim)

I have the initial orbit set to 190x205, but I'd like to have phasing angle and inclination offset correct, too.

If anyone can give me these values, I'll update the user-script accordingly :-)
« Last Edit: 05/23/2020 12:52 pm by CorvusCorax »

Offline CorvusCorax

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I tried to solve it myself.

In Northeastern direction, the ISS passes KSC at 20:07 UTC on May 27 (16:07 EDT) acording to https://www.n2yo.com/passes/?s=25544#

Launch is at 20:33 UTC ( 16:33 EDT )

Dragon takes aprox 10 minutes to reach orbit. But it also launches northeast catching up somewhat, so I'd only count aprox 7 minutes ish.

That gives ISS aprox 33 minutes head start (+- 3 minutes)

ISS has a period of 92.9 minutes in near circular orbit. That makes this a phase of 127° (+-11°)

So the rough estimate is: Dragon has to catch up to the ISS by about 1/3 of an orbit.

Relative inclination is harder to tell - since they can chose the liftoff time arbitrarily it should be zero, so it's basically down to whatever Falcon9's insertion accuracy is.

And Falcon9's insertion accuracy is pretty decent from what I've heard ;)

I might have the lateral error artificially high to keep the difficulty up ;)

Offline AndyH

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The Florida Today stream of 39A has been on a monitor since before yesterday's static fire.

Watching lights in the access arm and on the associated level of the tower/FSS last night brought on feelings that combined years of scifi and memories of black and white Apollo coverage.  Sweet excitement!

Quote from: Bradbury
For the wind was slowly rising and he let it take hold and blow him all the rest of the way across the desert to the rocket which stood waiting there.

T-4
« Last Edit: 05/23/2020 06:28 pm by AndyH »

Online FutureSpaceTourist

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Apologies if someone has already noted this

https://twitter.com/djsnm/status/1264274129705775104

Quote
Giant space fish swallows ISS

‘Obvious’ once someone has pointed it out ...

Offline Steven Pietrobon

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A preview of launch day. Anyone know what is on the astronauts left thigh? A packed lunch? Interesting seeing the new black coveralls worn by the pad technicians. The cockpit view is unfortunately too fuzzy to make out any details.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline spacenut

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Pack on the left thigh could be a survival kit in case of abort in a remote area.

Offline AndrewRG10

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It's an iPad

Offline matthewkantar

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Offline Nomadd

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Pack on the left thigh could be a survival kit in case of abort in a remote area.
"One forty-five caliber automatic; two boxes of ammunition; four days' concentrated emergency rations; one drug issue containing antibiotics, morphine, vitamin pills, pep pills, sleeping pills, tranquilizer pills; one miniature combination Russian phrase book and Bible; one hundred dollars in rubles; one hundred dollars in gold; nine packs of chewing gum; one issue of prophylactics; three lipsticks; three pair of nylon stockings"?
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline Nevyn72

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Pack on the left thigh could be a survival kit in case of abort in a remote area.
"One forty-five caliber automatic; two boxes of ammunition; four days' concentrated emergency rations; one drug issue containing antibiotics, morphine, vitamin pills, pep pills, sleeping pills, tranquilizer pills; one miniature combination Russian phrase book and Bible; one hundred dollars in rubles; one hundred dollars in gold; nine packs of chewing gum; one issue of prophylactics; three lipsticks; three pair of nylon stockings"?

Ahhhh, I see you've been to the ISS before!

Offline Lars-J

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It's an iPad

Yep. I assume check-lists/manuals and other resources and/or communication tools are loaded on them.

I assume you can think of them as the equivalent of flight check-lists that Soyuz crew read during ascent.
« Last Edit: 05/24/2020 07:19 am by Lars-J »

Online darkenfast

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Certainly the easiest access to a spacecraft since Gemini.
Writer of Book and Lyrics for musicals "SCAR", "Cinderella!", and "Aladdin!". Retired Naval Security Group. "I think SCAR is a winner. Great score, [and] the writing is up there with the very best!"
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Offline ace5

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Any official (SpaceX) information about the total weight of the spacecraft?

Offline Alexphysics

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It's an iPad

Yep. I assume check-lists/manuals and other resources and/or communication tools are loaded on them.

I assume you can think of them as the equivalent of flight check-lists that Soyuz crew read during ascent.

But to be fair Soyuz crews have been using iPads for every launch since the middle of the last decade. Much easier to follow the checklists that way and, like Bob and Doug, they have the old style paper checklists in case the iPads stop working :)

Offline banjo

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Which launch is nervier? Bob and Doug going up or the James Webb?

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