SpaceX Falcon 9 / Dragon 2 : SpX-DM2 : May 27, 2020 : DISCUSSION

[tyrred]

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

Bob and Doug are scheduled to go up on May 27th.  Those nerves are now.

[CorvusCorax]

I did some calculations and tests with SpaceX ISS-SIM (with some modifications)

After playing around with this for a bit, I think we can put a lower bound on the DeltaV budget Crew Dragon must have for ISS operations.

<snip>

All in all I get to 280 m/s minimum DeltaV to get to the ISS and back -- add some margin for failed ISS approaches and manual flight experiments, and we can conclude Dragon should have at least 300 m/s.

I'd give that an error of  +- 10 m/s - I don't know what altitude a phasing orbit might be - or whether its circular or not.  And I don't know how low Dragon needs to put its Perigee for reentry.

But all in all, I think a trip to ISS and back should be no less than 280 m/s plus margins, from where Falcon9 deploys Dragon.

Is there any official number of Dragon2's propellant load and DeltaV budget?

[atsf90east]

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"?

Did anyone else read that in Slim Pickens' voice?

[CorvusCorax]

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"?

Did anyone else read that in Slim Pickens' voice?

Shoot, a fella' could have a pretty good weekend in Vegas with all that stuff.

[king1999]

The Guardian put the dragon into a fairing. LOL.

https://www.theguardian.com/science/2020/may/24/elon-musks-crew-dragon-puts-america-back-in-the-space-race

[ugordan]

L-3 launch weather forecast still only 40% GO

Booster recovery area prediction actually got worse.

[woods170]

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

No, it isn't. That survival kit stuff is located behind panels in other parts of the spacecraft. The pack on the left thigh is a zippered bag containing several small items that could be needed when the crew has visors closed and the suit pressurized. It also contains items that would be immediately needed in case of an landing emergency or in-cabin systems malfunction. Stuff like a small, but powerful flashlight, seatbelt cutter, etc. On top of the pack sits an iPad. That iPad has a bluetooth-like link up with the spacecraft systems.

[woods170]

L-3 launch weather forecast still only 40% GO

Booster recovery area prediction actually got worse.

Booster recovery is a secondary objective. If the ascent route weather is good, including the abort zones, and only the booster recovery area is a no-go, than SpaceX will ditch the booster.

[ChrisC]

L-3 launch weather forecast still only 40% GO

Booster recovery area prediction actually got worse.

And to be clear, the 45th's forecasts and POVs only apply to LAUNCH, right?  The forecast/POVs of the "50" downrange abort points are being handled by SpaceX, and we're not seeing those, right?

So a 40% GO is actually likely far worse in reality, because downrange can only make it worse.

[CorvusCorax]

L-3 launch weather forecast still only 40% GO

Booster recovery area prediction actually got worse.

Booster recovery is a secondary objective. If the ascent route weather is good, including the abort zones, and only the booster recovery area is a no-go, than SpaceX will ditch the booster.

I think the recovery area is on the same flight path, as such a no-go for the recovery zone would almost certainly extend to at least some of the abort zones. Especially if you assume that Dragon's recovery constraints on sea state, wind and weather are more constrained than a landing Falcon9 booster.

[FlattestEarth]

Booster recovery is a secondary objective. If the ascent route weather is good, including the abort zones, and only the booster recovery area is a no-go, than SpaceX will ditch the booster.

How close are abort zones to droneship and thus how likely to have similar weather?

[rdale]

I'm not quite as pessimistic as USAF forecasters are (when you combine their 40% with the Atlantic forecasts that's a very low chance) but realistically it might be tough.

[Wargrim]

Pretty sure they will launch on the weekend, because that will be the first time in months that i will be at a place without internet.

[freddo411]

Booster recovery is a secondary objective. If the ascent route weather is good, including the abort zones, and only the booster recovery area is a no-go, than SpaceX will ditch the booster.

How close are abort zones to droneship and thus how likely to have similar weather?

One of the abort zones includes the drone ship area, but the abort zones are much, much larger than the area around the drone ship

[mulp]

I was surprised by the large number of people in close quarters with the crew. Including a reporter? doing interviews.

Are all these people living in NASA/SpaceX quarantine quarters for the past two weeks or more?

[TALsite]

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.

Nobody told this before, but for me with these numbers on the back,  the technicians helping the astronauts all the way to their spacecraft remember me the "all blacks" rugby team players.

I'd love see them dancing the "haka" before launch wishing them good luck.... 

Maybe I miss live sport.... 

Good luck Dragon!

[Comga]

https://twitter.com/elonmusk/status/1264633864627957761

Sorry to interrupt this serious discussion of technical details to gush but...
Isn't this a gorgeous vehicle?
Just what we'd want in the early part of the 21st century.
Clean lines
Integrated LAS
Those conformal solar cells
Grid fins and landing legs
A clean lined, aesthetic access bridge
Even a lovely sunrise.

[Nomadd]

Sorry to interrupt this serious discussion of technical details to gush but...
Isn't this a gorgeous vehicle?
Just what we'd want in the early part of the 21st century.
Clean lines
Integrated LAS
Those conformal solar cells
Grid fins and landing legs
A clean lined, aesthetic access bridge
Even a lovely sunrise.

I'd bet that most of the people on the planet would assume that's an artist's conception. Real rockets aren't that beautiful.

[AS_501]

It will be interesting to hear the crew's comments on Falcon 9's ride quality (shaking, vibrations, etc.).  Being a long and slender rocket like Saturn 5, will they experience a lot pitching and yawing up at the spacecraft end from first stage engine gimbaling?  Several Apollo/Saturn V crews noted that ("...like a ladybug riding the end of a whip antenna." someone said).  The Apollo 7 and Skylab crews complimented the Saturn IB first stage for its "smooth ride".  With a similar number of first stage engines, will Falcon 9 also produce low-level vibrations?  To any news media folks out there who may read this, please ask the crew about their ride into orbit in general.  Thanks.

[Lars-J]

It will be interesting to hear the crew's comments on Falcon 9's ride quality (shaking, vibrations, etc.).  Being a long and slender rocket like Saturn 5, will they experience a lot pitching and yawing up at the spacecraft end from first stage engine gimbaling?  Several Apollo/Saturn V crews noted that ("...like a ladybug riding the end of a whip antenna." someone said).  The Apollo 7 and Skylab crews complimented the Saturn IB first stage for its "smooth ride".  With a similar number of first stage engines, will Falcon 9 also produce low-level vibrations?  To any news media folks out there who may read this, please ask the crew about their ride into orbit in general.  Thanks.

It will be interesting to hear what they say, sure. Each launch vehicle probably has its own unique feel. But I doubt there will be any large surprises, they have likely a lot of sound, vibration, and G-load measurements over many F9 and Dragon flights.