Space stuff thread

Or, have an alternate landing site similar to what NASA had for the space shuttle when weather was bad at Cape Canaveral, if they couldn't land the shuttle in Florida, they landed in California.

The spaceX crew seem intent on trying landings on an unstable surface therefore they should have several landing barges that could be positioned in forecasted calmer areas of the Atlantic or Pacific oceans, that way spacex could pick a better landing spot an orbit or two or three before re-entry.

Why the desire to land on water?
It is the best simulator of what Falcon may run into in future landings. If you recall, it was reported that the Huygens probe landed with a splat when it touched down on Titan, but further study of the telemetry showed otherwise.

While earlier studies of data from Huygens determined the surface of Titan to be quite soft, scientists now think the surface consisted of a hard outer crust but is soft underneath, so that if an object put more pressure on the surface, it sank in significantly.

Source: http://What Happened During the Huygens Mission? | www.universetoday.com

I believe this is the main reason for the unstable landing testing; No one can tell for certainty what type of surface a ship will land on until they get to where their going and spacex needs to be prepared for any contingency.

I don't get this, maybe I have not noticed an article or two. The reason to test a floating landing pad, as far as I have understood, is that when the rocket is carrying a heavy load, it can't land on earth. Thinking that the load, heavy or not, will be left in space, the returning rocket is the same regardless of the load it took to the space.

What does the weight of the load to do with the landing capacities?

Kari, you ask some intriguing questions and I would like the opportunity to adjust my hypothesis, do you have a referral to an article that has the correlation between the load and "it can't land on Earth"?

Kari said:

The reason to test a floating landing pad, as far as I have understood, is that when the rocket is carrying a heavy load, it can't land on earth.

This may explain rcv's astonishment at the size of the explosion:

Kari said:

Thinking that the load, heavy or not, will be left in space, the returning rocket is the same regardless of the load it took to the space.

It can't be the same unless the launch vehicle failed to deliver its load. Who is doing this "thinking", the on-board computer?

Kari said:

What does the weight of the load to do with the landing capacities?

With what ever remaining load that is left in the launch vehicle, the computers have to calculate the remaining weight into the speed of descent, plus the time/distance to touchdown, plus the remaining fuel in order to calculate how much thrust to apply. It might look something like this:



The 1% is my estimate but, if any of these factors are off, Falcon will crash, notwithstanding structural failures.

I wanted to throw a jab into this to include Intel's new skylake processor and freezing during complex workloads, but that would be unfair because I don't know what type of computational power the Falcon is using.

Anak said:

Kari, you ask some intriguing questions and I would like the opportunity to adjust my hypothesis, do you have a referral to an article that has the correlation between the load and "it can't land on Earth"?

I read it on a Finnish news site, there are 5 of them I read daily, I am not sure which one it was. I will try to find the referral. I am sure I read it.

Kari said:

Anak said:

Kari, you ask some intriguing questions and I would like the opportunity to adjust my hypothesis, do you have a referral to an article that has the correlation between the load and "it can't land on Earth"?

I read it on a Finnish news site, there are 5 of them I read daily, I am not sure which one it was. I will try to find the referral. I am sure I read it.

Found the article, it was published on the national Finnish public broadcaster's news site on early hours of Monday Finnish time: SpaceX:n kantoraketin laskeutumisyritys epäonnistui jälleen | Yle Uutiset | yle.fi

Article is naturally in Finnish. The fourth paragraph after the first image says in Finnish:

SpaceX:n tavoitteena on tehdä raketeista uudelleenkäytettäviä, mikä pudottaisi huimasti kustannuksia ja tekisi nykyisistä kertakäyttöraketeista vanhanaikaisia. Merellä kelluvalle alustalle laskeutuminen mahdollistaisi raskaampaa rahtia toimittavien kantorakettien uudelleenkäytön. Painavampaa kuormaa kuljettavat raketit operoivat pienemmällä määrällä polttoainetta, jolloin paluu maalle ei ole mahdollista.

My free but quite accurate translation:

SpaceX's objective is to make rockets reusable, which would drop the costs dramatically and would make traditional rockets old-fashioned. Landing on a floating pad would make it possible to re-use even the rockets which are carrying heavier loads. Rockets with heavier loads operate with less fuel, making landing on land impossible

[Question on performance hit for attempting landing the first stage] We effectively lose, in terms of performance... It really depends on what we want to do with the stage if we were to do an ocean landing or a return to launch site landing. If we do an ocean landing, the performance hit is actually quite small at maybe in the order of 15%. If we do a return to launch site landing, it's probably double that, it's more like a 30% hit (i.e., 30% of payload lost).

Shit Elon Says - Transcript - SpaceX Press Conference September 29 2013

A Guy

Scientists reported Wednesday they finally have "good evidence" for Planet X, a true ninth planet on the fringes of our solar system.

The gas giant is thought to be almost as big as Neptune and orbiting billions of miles beyond Neptune's path — distant enough to take 10,000 to 20,000 years to circle the sun.

This Planet 9, as the two California Institute of Technology researchers call it, hasn't been spotted yet. They base their findings on mathematical and computer modeling, and anticipate its discovery via telescope within five years or less.

The two reported on their research Wednesday in the Astronomical Journal because they want people to help them look for it.

More: Video: Planet 9: Good evidence for another planet in solar system, Caltech scientists say | 89.3 KPCC

Kari said:

Found the article,

SpaceX's objective is to make rockets reusable, which would drop the costs dramatically and would make traditional rockets old-fashioned. Landing on a floating pad would make it possible to re-use even the rockets which are carrying heavier loads. Rockets with heavier loads operate with less fuel, making landing on land impossible

Kari, I see what your sayin' but, I need time to absorb the added information to reply. To me, the article you reference to seems like an oxymoron.

I need to understand why the returning rocket has an equal or more load than what it left with. Is it because the vehicle is bringing something back from the ISS or where-ever?

Code:

Landing on a floating pad would make it possible to re-use even the rockets which are carrying heavier loads.

And; Why:

Code:

Rockets with heavier loads operate with less fuel, making landing on land impossible[/

Why does a heavier load make landing on terra firma impossible, why do some loads qualify for less fuel?

This is not an inflection on you Kari, but there is information that is lacking here, and it is lacking from spacex's side; Which is understandable, because if I had secrets of this magnitude I would want to keep my cards close to my chest to. "I think they call it proprietary".

A Guy said:

[Question on performance hit for attempting landing the first stage] We effectively lose, in terms of performance... It really depends on what we want to do with the stage if we were to do an ocean landing or a return to launch site landing. If we do an ocean landing, the performance hit is actually quite small at maybe in the order of 15%. If we do a return to launch site landing, it's probably double that, it's more like a 30% hit (i.e., 30% of payload lost).

Shit Elon Says - Transcript - SpaceX Press Conference September 29 2013

A Guy

Bill, at the present time I'm not capable of understanding, let alone reading and comprehending the referral you provided about this spacex thing. Suffice it to say that I will take your reference under consideration and offer an opinion at a later time.



On a lighter note....

Kari said:

Scientists reported Wednesday they finally have "good evidence" for Planet X, a true ninth planet on the fringes of our solar system.

The gas giant is thought to be almost as big as Neptune and orbiting billions of miles beyond Neptune's path — distant enough to take 10,000 to 20,000 years to circle the sun.

This Planet 9, as the two California Institute of Technology researchers call it, hasn't been spotted yet. They base their findings on mathematical and computer modeling, and anticipate its discovery via telescope within five years or less.

The two reported on their research Wednesday in the Astronomical Journal because they want people to help them look for it.

More: Video: Planet 9: Good evidence for another planet in solar system, Caltech scientists say | 89.3 KPCC

If I had the opportunity to go to another planet, I would take it, but I believe my wife would have other considerations for me to think about.

Her main concern would be, the aloneness she would experience.

Anak said:

This is not an inflection on you Kari, but there is information that is lacking here, and it is lacking from spacex's side; Which is understandable, because if I had secrets of this magnitude I would want to keep my cards close to my chest to. "I think they call it proprietary".

I didn't take you asking the source not as an inflection on me :). Anyway, I seem to be totally unable to find anything else on this matter, wondering where the Finnish journalist has gotten that information.

Taking off to the east you get an assist from the earth's rotation.The most efficient use of energy (fuel) is to land downrange which is over water for a takeoff from Canaveral. To return to land would require extra fuel and/or a reduced payload.