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

[Rocket Science]

Thank you for the excellent article William and wonderful renders Nathan!

[Nomadd]

Thankyou for posting this as I did not stay up to watch it live. However I am generally disappointed on the low quality questions in these briefing. More than 75% are Elon, how do you feel about.... all general emotional questions. I want to see answers to technical questions, the best one was about the grid hydraulic pump failure. If I was able to ask a question I would like to know why SpaceX takes 27 hours to rendezvous with the ISS and the Russians take only 4 hours.

To rendezvous with an orbiting spacecraft - such as the station - you need to wait until the earth is turning so your launch-pad is exactly aligned with the orbital plane - while the earth constantly rotates. This means, unless you are capable of doing very expensive high deltaV plane-change manouvers, you end up with an instantaneous launch window.

Now the problem is, that you end up in that exact perfect spot only once every 24 hours, as the earth rotates....

Minor correction, this alignment of ISS/target and launch site actually happens twice every 24 hours.  On both the ascending and descending tracks.  But due to the nature of range/launch safety constraints and the allowable launch azimuths from a given launch site, you may end up being limited to only one of those in practice.  For launches from KSC/CCAFS to the ISS, SpaceX and others are limited to only launching into the ascending track (northeast).  Launching into the descending track (southeast) would result in overflying landmasses/populations which would violate the allowed safety limits.

Really, really minor correction...Once or twice every 23 hours 56 minutes.

[russianhalo117]

https://twitter.com/jaredhead/status/1101766548727844864

And SpaceX has said the nose cone on Dragon has opened. Woohoo! Now comes the real test: getting to @Space_Station, especially docking.

The nosecone uses the NDS docking mechanism to secure it in place for launch and landing so the NDS gets a partial checkout after launch.

[russianhalo117]

No lighting inside trunk? Pretty sure cargo dragon has lights there so that you can see separation clearly even in the dark.

There is lighting but it is not turned on during that phase of flight.

[mlindner]

Interesting headline on Gazeta.RU: Roscosmos didn't congratulate NASA and Musk for today's successful flight:

https://m.gazeta.ru/amp/science/2019/03/02_a_12218617.shtml

Desktop version: https://www.gazeta.ru/science/2019/03/02_a_12218617.shtml

If this is actually true then that really makes things quite sour. NASA didn't criticize Roscosmos over their repeated incidents such as drilling holes in their own spacecraft nor nearly killing one of their astronauts. It seems Roscosmos is getting more and more partisan.

[Ancient]

Anyone know if there is going to be a webcast for docking?

[Rocket Science]

Anyone know if there is going to be a webcast for docking?

Yes...
https://www.nasa.gov/multimedia/nasatv/schedule.html

[ThomasGadd]

Something strange that Elon said in the post conference, to I believe his second question, while talking about Dragon 2 he said “Hardly a part in common with Dragon 1 which in retrospect will probably change”
Not sure what to make of that. Any thoughts or did I just read his reply incorrectly?

Since Dragon2 is unlikely to change much given the strict certification process involved I assumed that meant that Dragon1 would be updated to have more commonality with Dragon2.

Isn't Dragon 1 in the process of being phased out?

Maybe they are going to use some Dragon 2 parts on upcoming Dragon 1 cargo flights.

Since NASA wants new Dragon 2's for crewed flights.   Spacex will refurbish flown ones for cargo.

I suspect after some flight time on the Dragon 2 NASA will certify them like used F9's.

[Jorge]

Thankyou for posting this as I did not stay up to watch it live. However I am generally disappointed on the low quality questions in these briefing. More than 75% are Elon, how do you feel about.... all general emotional questions. I want to see answers to technical questions, the best one was about the grid hydraulic pump failure. If I was able to ask a question I would like to know why SpaceX takes 27 hours to rendezvous with the ISS and the Russians take only 4 hours.

To rendezvous with an orbiting spacecraft - such as the station - you need to wait until the earth is turning so your launch-pad is exactly aligned with the orbital plane - while the earth constantly rotates. This means, unless you are capable of doing very expensive high deltaV plane-change manouvers, you end up with an instantaneous launch window.

Now the problem is, that you end up in that exact perfect spot only once every 24 hours, as the earth rotates....

Minor correction, this alignment of ISS/target and launch site actually happens twice every 24 hours.  On both the ascending and descending tracks.  But due to the nature of range/launch safety constraints and the allowable launch azimuths from a given launch site, you may end up being limited to only one of those in practice.  For launches from KSC/CCAFS to the ISS, SpaceX and others are limited to only launching into the ascending track (northeast).  Launching into the descending track (southeast) would result in overflying landmasses/populations which would violate the allowed safety limits.

Really, really minor correction...Once or twice every 23 hours 56 minutes.

Equally minor correction... more like 23 hours 36-ish minutes. Four minutes earlier per day due to the difference between the sidereal and solar day, 20-ish more minutes due to the westward regression of the ISS orbit ascending node caused by the Earth's equatorial bulge. It's "20-ish" because it's a function of altitude and inclination. ISS inclination doesn't vary much but altitude can.

The previous answers to this question are accurate as far as they go, but they're missing something. I'm just going to throw this out there, from NASA's NTRS (note, per the revision log on page 2, that this document is no longer export controlled):

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170001943.pdf

Further hint: paragraph 3.4.2.1. Have fun.

/lurk

[Svetoslav]

I've been wondering - will astronauts be allowed to enter Crew Dragon (possibly yes), for how long and will it be shown on NASA TV?

[Jorge]

I've been wondering - will astronauts be allowed to enter Crew Dragon (possibly yes), for how long and will it be shown on NASA TV?

They pretty much have to, in order to extract the 181 kg of equipment and supplies, and put in the science samples and failed spacesuit.

March 3, Sunday:
- 08:30 UTC NASA TV Coverage of the Rendezvous and Docking of the SpaceX/Crew Dragon Spacecraft to the ISS
- 11.00 UTC Dragon SpX-DM-1  Docking
- 13:30 UTC NASA TV Coverage of the Hatch Opening of the SpaceX/Crew Dragon Spacecraft
- 13.45 UTC hatch opening by flight engineer Anne McClain and commander Oleg Kononenko.
DM-1 will deliver 181 kg of equipment and supplies for the station's crew and return with science samples, as well as a failed part of a spacesuit for analysis and repair
- 15:35 UTC NASA TV Coverage of the SpaceX/Crew Dragon special welcoming ceremony by the ISS crew.

[MKremer]

I've been wondering - will astronauts be allowed to enter Crew Dragon (possibly yes), for how long and will it be shown on NASA TV?

Hatch opening should be live. And, yes, they'll have to enter inside since there is some 200kg or so of cargo to be unloaded and some to be loaded for return.

I would guess that they will go through the same kind of air sampling with masks and eye protection, like the first visits of the other cargo craft that have berthed and docked to the station.

[FutureSpaceTourist]

https://twitter.com/enterprise_flt/status/1102023954078879744

The Shelton family of Dallas was known for the tradition of sending flowers to @NASA_Johnson for Shuttle missions. We haven't had a delivery since 2011 - until I got a call on console today. A reminder of what @Commercial_Crew means for this nation and the world. Go @spacex!

https://twitter.com/enterprise_flt/status/1102026529293377536

As the tradition goes, one white rose to signifies the sacrifices of Columbia, Challenger, and Apollo 1. The other roses are for the current @Space_Station crew of 3. And then there's an extra rose - why? It's for #ripley, the @SpaceX dummy. And it's the only fake rose.

[catdlr]

Looks like the seats have the ability to slide back under the seat back, when not used to (see picture attached)??

[mlindner]

One thing I don't like about the SpaceX coverage is that they feel the need to always be talking and never have silence. (Or have music playing.)

[Scylla]

Looks like the seats have the ability to slide back under the seat back, when not used to (see picture attached)??

If your talking about the two center seats, they drop down out of the way of the control panal so  the Commander and Pilot can get in to them. They then rise up to the control panel.

[Targeteer]

why isn't the keep out sphere mentioned during Soyuz and Progress approaches?

[mlindner]

why isn't the keep out sphere mentioned during Soyuz and Progress approaches?

Another case of the commercial crew groups being held to higher standards than Shuttle or Roscosmos ever were?

[mlindner]

Sounds like SpaceX lets its people talk over the NASA loop audio as well. They also can't mute music properly when astronauts are talking.

[EspenU]

Dragon 2 HUD view - first time we've seen this. Heading to the KOS (Keep Out Sphere), but that screen. This is what the astros will use. Very nice layout.

Like taken right out of a sci-fi movie. Makes the view from Soyuz look a little dated