SpaceX Falcon 9 CRS8 Launch & Landing Attempt 4:43PM ET

[PottedMeat]

Reaction at ULA headquarters:

they probably just OK'd a huge funding boost to their vulcan development program and wrote a fat check to jeff bezos

 

[MongGrel]

NASA currently has two rovers on Mars, a probe orbiting Saturn, another probe on it's way Jupiter, and a NASA probe flew by Pluto last year. NASA is the only space agency in the world to send any probes to the outer planets.

+1

Like many people have said in other threads, NASA is focused more on deep space.

Boost to orbit is becoming a private venture.

 

[dr150]

1.) 1st Putin Twitter message saying that it's fake CGI.

2.) 2nd Putin Twitter message saying he's going to ramp up his nuclear arsenal to fend off the CGI.

 

[Phoenix86]

+1

Like many people have said in other threads, NASA is focused more on deep space.

Boost to orbit is becoming a private venture.

Yeah, but Musk's eyes are on Mars.

 

[Markbnj]

Absolutely out of this world amazing. What a sight.

 

[IronWing]

Cool. What keeps it from falling over once it lands? Even in calm seas, the barge is rocking.

 

[Phoenix86]

Cool. What keeps it from falling over once it lands? Even in calm seas, the barge is rocking.

Wide legs and it's bottom heavy. Most of the fuel is spent, so it's mostly just the engine weight and empty tanks.

 

[mnewsham]

Cool. What keeps it from falling over once it lands? Even in calm seas, the barge is rocking.

As the other poster said, nice wide legs and the rocket engine bits are all at the bottom making it very bottom heavy.

However, before they move the ship they will secure it into place (I believe they weld it to the deck).

 

[MrSquished]

neat-0

 

[PottedMeat]

4K video from chase plane:
you can see it hop a little to the left

https://www.youtube.com/watch?v=sYmQQn_ZSys&feature=youtu.be

video from top of stage with grid fins adjusting for winds and the hop

https://twitter.com/SpaceX/status/718605741288894464

 

[sportage]

Landing just like all those vintage Sci-Fi movies.

 

[William Gaatjes]

Maybe a silly question, but is it because of the amount of fuel left and the trajectory into space that the rocket was landed in open sea ?
Was the nearest point on land to populated to allow the rocket to touch down on land, meaning safety reasons ?

 

[mnewsham]

Maybe a silly question, but is it because of the amount of fuel left and the trajectory into space that the rocket was landed in open sea ?
Was the nearest point on land to populated to allow the rocket to touch down on land, meaning safety reasons ?

It's a mix of different factors, it has to do with the orbit and payload of the rocket, as well as where they are launching from.
They also need major government approval for land based landings. So a sea based landing is much easier to coordinate.

This way they can launch the rocket and have it follow it's natural parabolic trajectory and have the drone ship waiting in the area it's expected to come down near, then you use a bit of fuel to slow down and land safely on the barge.
The other alternative is instead of allowing it to follow it's natural parabolic course, you allow a larger margin of fuel and do some extra burns to bring the rocket back to land. This however takes fuel away from the main mission and you either suffer a reduced payload, or a different orbit, and depending on mission requirements, this isn't always possible or feasible, and since the majority of the planet is covered in water, it just makes sense to be able to land on water if possible hence the drone ship.

 

[William Gaatjes]

It's a mix of different factors, it has to do with the orbit and payload of the rocket, as well as where they are launching from.
They also need major government approval for land based landings. So a sea based landing is much easier to coordinate.

This way they can launch the rocket and have it follow it's natural parabolic trajectory and have the drone ship waiting in the area it's expected to come down near, then you use a bit of fuel to slow down and land safely on the barge.
The other alternative is instead of allowing it to follow it's natural parabolic course, you allow a larger margin of fuel and do some extra burns to bring the rocket back to land. This however takes fuel away from the main mission and you either suffer a reduced payload, or a different orbit, and depending on mission requirements, this isn't always possible or feasible, and since the majority of the planet is covered in water, it just makes sense to be able to land on water if possible hence the drone ship.

I see. I kind of have a doom scenario in my head where they have a heavy storm coming up on sea. Of course, there are weather predictions to base the schedule on, but there also schedules to be met with respect to the trajectory and refueling of the ISS. And of course, the wind can change on sea just like that within an hour. I imagine that with heavy weather, getting that first stage back to touch down on the drone ship may not be easy. Perhaps they should invest into a bigger ship ?

 

[mnewsham]

Perhaps they should invest into a bigger ship ?

They're already fairly large ships, about the size of a narrow football pitch.

They also have fairly advanced thrusters designed to keep it as steady and level as possible during rough seas. Yesterday wasn't exactly the calmest weather and they landed it.

 

[Brovane]

Maybe a silly question, but is it because of the amount of fuel left and the trajectory into space that the rocket was landed in open sea ?
Was the nearest point on land to populated to allow the rocket to touch down on land, meaning safety reasons ?

A RTLS (Return to Launch Site) boost back by the Falcon-9 results in about a 30% payload hit to LEO. A drone ship landing by the Falcon-9 results in about a 15% payload hit to LEO. For the CRS-8 launch, SpaceX could have done a RTLS but they decided to attempt the drone ship landing because they hadn't been successful yet. For launches to higher energy orbits like GTO, the 1st stage has greater velocity at stage separation. This greater velocity down range makes it impossible to do a RTLS so with GTO launches the only option is a drone ship landing.

 

[Brovane]

I see. I kind of have a doom scenario in my head where they have a heavy storm coming up on sea. Of course, there are weather predictions to base the schedule on, but there also schedules to be met with respect to the trajectory and refueling of the ISS. And of course, the wind can change on sea just like that within an hour. I imagine that with heavy weather, getting that first stage back to touch down on the drone ship may not be easy. Perhaps they should invest into a bigger ship ?

As re-usability advances then I expect you will see No-Go weather for both launch and landing. Space launches can be scrubbed for a variety of reasons and even for yesterday's launch, SpaceX and NASA had already selected a backup window launch date/time which was today for the CRS-8 mission. Usually for most trajectories you have at least one launch window each day. As for the ISS they is plenty of margin for supplies and it is never that tight that a missed launch window would jeopardize operations in orbit.

 

[William Gaatjes]

Yep, i kind of expected that if there was one place where redundancy could be found, it would in space exploration. ^_^

 

[MongGrel]

http://arstechnica.com/science/2016...-be-no-spacex-and-its-brilliant-boat-landing/