SpaceX Falcon 9 / Dragon 2 : SpX-DM1 : March 2, 2019 : DISCUSSION

[ZachS09]

...

LAUNCH, LANDING AND DRAGON DEPLOYMENT
(all times are approximate)
  Hour/Min/Sec   Events
  +00:00:58   Max Q (moment of peak mechanical stress on the rocket)
  +00:02:33   1st stage main engine cutoff (MECO)
  +00:02:38   1st and 2nd stages separate
  +00:02:44   2nd stage engine starts
  +00:07:48   1st stage entry burn
  +00:08:57   2nd stage engine cutoff (SECO-1)
  +00:09:26   1st stage entry burn
  +00:09:37   1st stage landing
  +00:10:59   Crew Dragon separates from 2nd stage
  +00:12:00   Dragon nosecone open sequence begins

Why are there 2 first stage entry burns? From the listed times, the seconds one should be the landing burn, although 11 seconds is a short landing burn. Usually those are 30 sec for a single engine landing.

You're right. They meant to write "1st stage landing burn" at T+09:26. And it's an 11-second landing burn because they want to do a high retrothrust burn similar to the one we heard about for GovSat 1.

[PahTo]

From the press briefing (below).  I hope Stephen got his answer (drives me crazy that they don't share the numbers with the public).  The "Internet" suggests Crew Dragon may weigh 11-ish tonnes fueled without cargo, and up to 14+ tonnes with cargo.  Whatever the DM1 number, I expect this to be the heaviest-ever Falcon 9 payload.

"Stephen Clark, Spaceflight Now: Hi, Stephen Clark, Spaceflight Now, again. One question for maybe Hans or Kathy. Do you know about what the weight of the spacecraft is, in terms of pounds or kilograms at launch with all the fuel and cargo or crew loaded. About how heavy is it? And a little way ahead for the next week, you mentioned testing and analysis, what sort of milestones do you have over the next seven days to get ready for the launch? Fueling of the spacecraft with hypergolic fuel, et cetera.

[snip]

 - Ed Kyle

Really interesting discussion about performance, RTLS, flatter trajectory.  Does anyone know how the DM1 vehicle is configured? (sorry if I missed it, please point me).  That is, are there four seats with approx 225lb bags of ballast, supplies arranged in the cabin as they would be for a manned mission, some ballast in the trunk to simulate non-pressurized cargo (would they even do that, or is the ECLSS housed in the trunk)?  Obviously I haven't followed Dragon 2 very closely, thanks for the "instant education"--time to get to know the future...

[Rondaz]

SpaceX’s Crew Dragon and Falcon 9 head to Pad 39A for historic launch debut

By Eric Ralph  Posted on February 28, 2019

https://www.teslarati.com/spacex-crew-dragon-falcon-9-rollout/

[spacebleachers]

Rollout view this morning is awesome with the fog. Kinda reminds me of when Challenger rolled out to the pad and the aerial photos taken above the fog.

[DigitalMan]

From the press briefing (below).  I hope Stephen got his answer (drives me crazy that they don't share the numbers with the public).  The "Internet" suggests Crew Dragon may weigh 11-ish tonnes fueled without cargo, and up to 14+ tonnes with cargo.  Whatever the DM1 number, I expect this to be the heaviest-ever Falcon 9 payload.

"Stephen Clark, Spaceflight Now: Hi, Stephen Clark, Spaceflight Now, again. One question for maybe Hans or Kathy. Do you know about what the weight of the spacecraft is, in terms of pounds or kilograms at launch with all the fuel and cargo or crew loaded. About how heavy is it? And a little way ahead for the next week, you mentioned testing and analysis, what sort of milestones do you have over the next seven days to get ready for the launch? Fueling of the spacecraft with hypergolic fuel, et cetera.

[snip]

 - Ed Kyle

Really interesting discussion about performance, RTLS, flatter trajectory.  Does anyone know how the DM1 vehicle is configured? (sorry if I missed it, please point me).  That is, are there four seats with approx 225lb bags of ballast, supplies arranged in the cabin as they would be for a manned mission, some ballast in the trunk to simulate non-pressurized cargo (would they even do that, or is the ECLSS housed in the trunk)?  Obviously I haven't followed Dragon 2 very closely, thanks for the "instant education"--time to get to know the future...

I recall someone (Gerst?) saying the weight of the people was negligible so I do not think there is ballast for those seats, except for the lone Starman.

[Rondaz]

Weather Prediction 80 Percent ‘Go’ for Demo-1 Launch; Televised Prelaunch Briefing Today

Anna Heiney Posted on February 28, 2019

The first launch of SpaceX’s Crew Dragon spacecraft aboard the company’s Falcon 9 rocket is now only two days away. Liftoff of the uncrewed flight test, called Demo-1, is targeted for 2:49 a.m. EST from Kennedy Space Center’s Launch Complex 39A. The milestone will mark the first launch of a commercially built American rocket and spacecraft designed to carry astronauts to the International Space Station.

Meteorologists with the U.S. Air Force’s 45th Weather Squadron continue to predict an 80 percent chance of favorable weather for launch on Saturday morning, with the possibility of thick clouds or cumulus clouds posing the main concern.

NASA will broadcast a prelaunch briefing from Kennedy at 4 p.m. today. Participants are:

Kathy Lueders, manager, NASA Commercial Crew Program
Joel Montalbano, deputy manager, International Space Station Program
Hans Koenigsmann, vice president, Build and Flight Reliability, SpaceX
Pat Forrester, chief, Astronaut Office, Johnson Space Center
Melody C. Lovin, launch weather officer, 45th Weather Squadron
Learn more about the mission and NASA’s Commercial Crew Program in the press kit and by following the @commercial_crew on Twitter and commercial crew on Facebook.

https://blogs.nasa.gov/commercialcrew/2019/02/28/weather-prediction-80-percent-go-for-demo-1-launch-televised-prelaunch-briefing-today/

[DaveJ576]

Clarification needed: Does the nose cap stay open the whole time on orbit, or does it open only during the rendezvous and docking phase? SpaceX animation indicates the later.

[OccasionalTraveller]

Clarification needed: Does the nose cap stay open the whole time on orbit, or does it open only during the rendezvous and docking phase? SpaceX animation indicates the later.

The timeline shows nosecone opening starting at +12 minutes into the mission, just over one minute after separation from the second stage. No indication how long it stays open for after undocking, but I would imagine it might stay open for some time after to make it easier to dock again if required. It certainly has to close (or be jettisoned) for re-entry. The press kit states five hours between undocking and deorbit burn, so some time in between those two points!

We know that it can be jettisoned in an emergency, since there are buttons to trigger the pyros on the control panel.

[DecoLV]

T-0 was 2:48. Where did the extra minute come from?

[Norm38]

On rollout, cargo dragons (CRS-16) didn't roll to the pad until the day of launch.  Why are they rolling out today instead of Saturday?

[abaddon]

On rollout, cargo dragons (CRS-16) didn't roll to the pad until the day of launch.  Why are they rolling out today instead of Saturday?

Well, the launch is at 2:48am Saturday, so they would roll out Friday.  A day early doesn't seem surprising to me when it's the first Crew vehicle launch.

[Zed_Noir]

On rollout, cargo dragons (CRS-16) didn't roll to the pad until the day of launch.  Why are they rolling out today instead of Saturday?

More time for the press to get video coverage and standup interviews with the vehicle stack as the backdrop. It is the first crew rated US spacecraft going up since the last Shuttle landed in 2011.

[MostlyHarmless]

On rollout, cargo dragons (CRS-16) didn't roll to the pad until the day of launch.  Why are they rolling out today instead of Saturday?

Also, could be because there is probably less time-critical cargo to loaded for this test flight?

[High Bay 4]

During the CRS-16 pre-launch briefing Hans mentioned using Firing Room 4 at the LC-39 LCC for future launches.  Anyone know if it will be used for this Saturday's DM-1 launch?

[MostlyHarmless]

T-0 was 2:48. Where did the extra minute come from?

Liftoff times are sometimes adjusted as the ISS orbital parameters are refined by NORAD.  Aligning exactly with the ISS orbital plane means less delta-V needed for plane adjustments.

At least that's my semi-educated guess.   

[NX-0]

On rollout, cargo dragons (CRS-16) didn't roll to the pad until the day of launch.  Why are they rolling out today instead of Saturday?

Also, could be because there is probably less time-critical cargo to loaded for this test flight?

With the Crew Access Arm, it should be easier to access for late-stow.
I wonder if Cargo D2 will allow that option.

[Alexphysics]

T-0 was 2:48. Where did the extra minute come from?

As the launch approaches the launch time is refined with updated orbital ISS data and it is now at 07:49:03 UTC. I wouldn't be surprised if it moves a few seconds left or right in these few dozen hours until launch.

[Norm38]

Well, the launch is at 2:48am Saturday, so they would roll out Friday.  A day early doesn't seem surprising to me when it's the first Crew vehicle launch.

***Smacks forehead***
Somehow I was off a day, thinking the launch was Saturday night/Sunday morning.  But it's tomorrow night.  Hey, one less day to wait!

[Lars-J]

Clarification needed: Does the nose cap stay open the whole time on orbit, or does it open only during the rendezvous and docking phase? SpaceX animation indicates the later.

I believe the star trackers are under the nose cap, so the nose cap will likely open quickly after launch and stay open until shortly before re-entry.

[bkellysky]

Three questions:
Launch time in the oh-so-dark. I assume that's orbital dynamics with the ISS' orbit?  It seems like in the 1960s they tried to do daylight launches to get the best views. 

In the eastern USA is there a chance to see powered flight (8 minutes 57 seconds up along the east coast, like the STS) or is the 'flat' trajectory keeping it below our horizon?

We have a low in the northwest overflight of the ISS a few hours before docking. Heavens-above.com predicts magnitude -1.9, not as bright as typically.  Is that too low and too dim to see Dragon?
https://heavens-above.com/passdetails.aspx?lat=41.034&lng=-73.7629&loc=White+Plains&alt=65&tz=EST&satid=25544&mjd=58545.4088050497&type=V
Thank you - pointing to where I may have missed the answer to the first question would be fine.
If you have a link I missed to visibility of Dragon's powered flight, let me know.
Of course, the weather not looking favorable in the northeast USA this weekend.
bob