SpaceX and other space stuff

[ahc]

Crew Dragon undocking and splashdown:

Sat., Aug. 1, 7:34 p.m. EDT: NASA SpaceX Demo Mission-2 Undocking

Sun., Aug. 2, 2:42 p.m. EDT: NASA SpaceX Demo Mission-2 Splashdown

 

[ahc]

I wonder how much time they have to get it zeroed in on the right direction once they hit the go to Mars button. Unless it was in geostationary orbit the firing would have to be calculated for each orbit window where it was 'more or less' headed in the right direction.

It's preplanned and done using "Orbital Mechanics". Here's a link:

Orbital mechanics - Wikipedia

And here's the quick excerpt from Wikipedia:

Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft. The motion of these objects is usually calculated from Newton's laws of motion and law of universal gravitation. Orbital mechanics is a core discipline within space-mission design and control.

Celestial mechanics treats more broadly the orbital dynamics of systems under the influence of gravity, including both spacecraft and natural astronomical bodies such as star systems, planets, moons, and comets. Orbital mechanics focuses on spacecraft trajectories, including orbital maneuvers, orbital plane changes, and interplanetary transfers, and is used by mission planners to predict the results of propulsive maneuvers. General relativity is a more exact theory than Newton's laws for calculating orbits, and is sometimes necessary for greater accuracy or in high-gravity situations (e.g. orbits near the Sun).

******

If you saw the movie "Hidden Figures", that's what those ladies were doing.

 

[Downunderwonder]

It's preplanned and done using "Orbital Mechanics". Here's a link:

Orbital mechanics - Wikipedia

And here's the quick excerpt from Wikipedia:

Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft. The motion of these objects is usually calculated from Newton's laws of motion and law of universal gravitation. Orbital mechanics is a core discipline within space-mission design and control.

Celestial mechanics treats more broadly the orbital dynamics of systems under the influence of gravity, including both spacecraft and natural astronomical bodies such as star systems, planets, moons, and comets. Orbital mechanics focuses on spacecraft trajectories, including orbital maneuvers, orbital plane changes, and interplanetary transfers, and is used by mission planners to predict the results of propulsive maneuvers. General relativity is a more exact theory than Newton's laws for calculating orbits, and is sometimes necessary for greater accuracy or in high-gravity situations (e.g. orbits near the Sun).

******

If you saw the movie "Hidden Figures", that's what those ladies were doing.

I never saw a slide ruler or a book of log tables in that film, although I think I recall her calling for a number at one point and doing the rest longhand. I think some movie licence was used.

The question was more about how accurately they can control the motor power and guidance control squirts to get it pointed where it needs to go at the right speed that Mars catches it at the other end.

For my money they would calculate a spot to aim for and go 'at' and then accelerate knowing that Mars will be in the another spot in a few months time. My astrophysics is very limited. At some point the sun takes over as the main influence on the ship's path relative to home, then Mars takes over.

 

[MJ5150]

Weather permitting, tonight will be the last night for me to wave to Bob and Doug as they fly by.
After Sunday, no more ISS for a while. I go out every night, sometimes twice, so it'll be weird not doing that anymore.

-Mike

 

[SBassman]

I have been trying to find the timeline for this weekend, unsuccessfully, until now.

- leave the space station around 7:30 pm ET Saturday
- 19-hour journey home - splashdown scheduled for 2:42 pm ET Sunday.

 

[ahc]

I'm thinking the return might be delayed by Hurricane Isaias. Of the seven potential splashdown sites for Crew Dragon off the coasts of Pensacola, Tampa, Tallahassee, Panama City, Cape Canaveral, Daytona, and Jacksonville, a bunch of them could be affected.

 

[Downunderwonder]

I have been trying to find the timeline for this weekend, unsuccessfully, until now.

- leave the space station around 7:30 pm ET Saturday
- 19-hour journey home - splashdown scheduled for 2:42 pm ET Sunday.

So, ^18.45 of relative boredom followed by a few minutes of clenching bottom followed by a nervous parachute ride?

 

[ahc]

So, ^18.45 of relative boredom followed by a few minutes of clenching bottom followed by a nervous parachute ride?

Yup. Same as it ever was.

 

[Downunderwonder]

Does anyone know at what stage they have a reentry burn or is it multiple stages? 19 hours seems a long time to 'climb down''.

 

[SBassman]

Does anyone know at what stage they have a reentry burn or is it multiple stages? 19 hours seems a long time to 'climb down''.

Yes. I would like to know that, too. There has to be a very short window of actual danger when they are re-entering, and I haven't found a specific reference to it yet.

 

[Downunderwonder]

In other space news, RocketLab got FAA approval to resume launches of their Electron lifter. Apparently it has been determined ( decided ) a faulty switch ( must have) downed the last one.

 

[ahc]

Does anyone know at what stage they have a reentry burn or is it multiple stages? 19 hours seems a long time to 'climb down''.

Yes. I would like to know that, too. There has to be a very short window of actual danger when they are re-entering, and I haven't found a specific reference to it yet.

The actual deorbit burn is done using the Dragon's thrusters as opposed to the retro rockets that were strapped to the Mercury, Gemini and Apollo capsules' heat shields. It a 15 minute +/- process on the last orbit. Here's how the deorbit burn worked on Crew Dragon Demo-1, the uncrewed test of the Crew Dragon. It should be similar for this flight.

Coming Up: Crew Dragon Deorbit Burn – Commercial Crew Program

 

[SBassman]

The actual deorbit burn is done using the Dragon's thrusters as opposed to the retro rockets that were strapped to the Mercury, Gemini and Apollo capsules' heat shields. It a 15 minute +/- process on the last orbit. Here's how the deorbit burn worked on Crew Dragon Demo-1, the uncrewed test of the Crew Dragon. It should be similar for this flight.

Coming Up: Crew Dragon Deorbit Burn – Commercial Crew Program

Thank you. Much appreciated.

 

[ahc]

Thank you. Much appreciated.

All part of the friendly, courteous service here at TB Mission Control!

 

[Stewie26]

All part of the friendly, courteous service here at TB Mission Control!

Thanks for overseeing TB Mission Control AHC.

 

[SBassman]

So those videos were excellent. Has anyone heard if we will have video for the undocking and that chaser plane again for re-entry?

 

[SBassman]

 

[MJ5150]

So those videos were excellent. Has anyone heard if we will have video for the undocking and that chaser plane again for re-entry?

SpaceX Crew Dragon carrying NASA astronauts to depart space station today. Here's how to watch it live. | Space.
The wife and I have planned our day around watching this.

Here's the direct link to the NASA YouTube channel where you can set a reminder to alert you when the program starts.


-Mike

 

[bholder]

SpaceX Crew Dragon carrying NASA astronauts to depart space station today. Here's how to watch it live. | Space.
The wife and I have planned our day around watching this.

Here's the direct link to the NASA YouTube channel where you can set a reminder to alert you when the program starts.


-Mike

Just came here to post exactly this. Well, except the "wife and I" part, hehe.

 

[Downunderwonder]

The actual deorbit burn is done using the Dragon's thrusters as opposed to the retro rockets that were strapped to the Mercury, Gemini and Apollo capsules' heat shields. It a 15 minute +/- process on the last orbit. Here's how the deorbit burn worked on Crew Dragon Demo-1, the uncrewed test of the Crew Dragon. It should be similar for this flight.

Coming Up: Crew Dragon Deorbit Burn – Commercial Crew Program

I don't have internet data to burn on YouTube so apologies if this is covered, just wondering what takes up the other 18+ hrs of capsule free orbiting before reentry? One would assume they could leave detaching until the station passed say 2hrs away from reentry point leaving plenty of time for final system checks before retro burn. Obviously something takes a lot more time!