Talk-Polywell.org

What do we call that, a Falcon 50?

I'd rather not be seated behind that geodesic windshield at Max Q. Put a few 4k cameras outside and I'll watch on a flat screen, thank you very much.

Let's see how Falcon Heavy will develop. I think that video is way too much ambitious considering the point where SpaceX is at the moment.
I mean, I love ambition, but that type of ambition is a tad too exaggerated! As of today I will be already very happy with a Falcon Heavy where the 3 booster can be reused at least 10 times!!

Tom Ligon wrote:What do we call that, a Falcon 50?

Looks like a Falcon XX

Something similar, at least. That shows the Falcon XX as having one core with 6 engines. Typo?

The booster in that animation seemed to have dozens of small engines. Supposedly everything will be using Merlin 2 at that point. Maybe this is an early concept illustrated as using the Merlin 1D? In which case it would have 54 engines to be the equivalent of 6 Merlin 2s?

One has to wonder where and what the pad for the XX Heavy will be. That is one big ass rocket.

The chart three posts above is possibly obsolete. Back in 2010 the Merlin 2 was mentioned as a 1.7 million pound thrust kerosene/ oxygen engine. Since then I am not aware of any further development to an actual engine. My impression, is that instead of this, Space X is putting their money into methane/ oxygen Raptor engines. This was initially envisioned as being as powerful as the proposed Merlin 2, but for various reasons is now targeted at about 600 thousand plus thrust. As such the BFR- MCT- IPT has 42 engines on the booster. The booster is fully reusable and could be used for just about any super large payload to LEO, so a separate Falcon XX seems unlikely. It's size will be about the same as the Falcon XX (relative to the Saturn 5).

Actually I don't know what the booster will be called, but it seams that the Raptor engine is the path to the future of super heavy lift- at least for SpaceX. In the presentation today there was three vehicles presented- the Inter Planetary Transport, an orbital tanker derived from the IPT, and the booster. With 42 Raptors at ~ 600+ thousand pounds of thrust each, it adds up to a lot of thrust for the booster.

Some slides from Musk's presentation is linked below

http://imgur.com/a/20nku

A more up to date rocket comparison is at:

http://imgur.com/a/w22oe

The actual presentation video:

https://www.youtube.com/watch?v=IFA6DLT1jBA

Dan Tibbets

ladajo wrote:One has to wonder where and what the pad for the XX Heavy will be. That is one big ass rocket.

Didn't you see the video above, where they cleared a pad to make room for a new one? Yeah, it is rather close to the KSC HQ. But if the XX goes, the fireball might not quite reach the HQ.

No worries! Human-rated. Safe as houses.

This raptor booster engine has 3 million Newton thrust at sealevel with a SL Isp of 334 and a vac Isp of 360.
The vacuum version has even higher thrust and Isp with 3500 kN and 382 respectively.
All that in a package about the same size as the Merlin 1D!! This opens crazy possibilities!
Musk indicated that the tanker version of the upper stage could be an SSTO (though for some reason he thinks it could not be recovered). I think that if they optimized it for the role (e.g. shortened engine bells on the outer engines), they could have an RLV SSTO with a significant payload (e.g. a Dragon2) to LEO. With orbital refueling, they could make this the workhorse for not only going to LEO but also GEO and the moon.
It could bring the cost of access to space down to levels that could bring about a space based economy.

ladajo wrote:One has to wonder where and what the pad for the XX Heavy will be. That is one big ass rocket.

In the start it will be "Pad 39A" according the Q/A session that was held after the presentation.
It looks like when they built this pad it was done with much bigger rockets in mind than the Saturn.

I dunno Giorgio, I have been to 39A, and I am not sure it could handle it as built, however I leave the real assessment to the structural guys who built it.. Even the buffer zone may need to be reassessed. The structures put inside the buffer zone (used to be at least) are built for the air and ground dynamic effects of a heavy boost. I remember being in the woods in the buffer zone at Stennis many a time, 5 or more miles from the test stands when they did SSME full firings, and the swamp would rumble.

Perhaps the reason they don't expect to recover the tanker booster is that it IS an SSTO.

RWB gave me a quote (and then never forgave me when I had a character use it in a story): "The best SSTO has two stages." There are reasons we use multi-stage rockets. They typically have better margin. The STS was not really SSTO, it had SRBs in order to get it flying. The SRBs were recoverable.

So if you can build an SSTO, you can bet you're compromising somewhere to do it. Now consider that instead of coming back from a suborbital trajectory, it has to re-enter from LEO. It is coming down faster and further. That's a nasty problem, considering they're landing boosters now on the last few teacups of fuel.

If you could put a parachute on it... but then presumably that throws the spatial precision of your landing way off. So now you're landing in water. My understanding is that this is a problem for big rockets because they just don't have the structural integrity to survive the bouncing and tipping over.

As a different strategy, I'd say hey, if you're not recovering your tanker - turn it into a space habitat.

On that note, though, how much extra mass is it? Maybe take it with you to mars? Then re-purpose it on ground. Twice the living space.

From wikipedia:

Falcon 9
-----------
3.7m diameter (divided by 2, squared = 3.4225 pi area)
9 merlin engines


ITS
----
12m diameter (divided by 2, squared = 36 pi area)
42 raptor engines


42/9 = 4.667 engine # ratio
36/3.4225 = 10.518 area ratio

Thus, at about the same packing density, the raptors will have about twice the area as the merlins.
It's listed as having about 3x the vacuum thrust (3,000 vs 914), so this sounds ballpark.


So comparing to a Falcon 9, we're looking at engines about twice the size, and a hull about 3x (edited) the diameter.

So... bigger than a falcon XX.

...errr... 3x the diameter.

...of the falcon 9