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Elon Musk confirms Falcon 9 first stage single-stage-to-orbit (SSTO) capable.


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Elon Musk Verified account �@elonmusk @TobiasVdb
The F9 booster can reach low orbit as a single stage if not carrying the upper stage and a heavy satellite.
https://twitter.com/elonmusk/status/669132749500887040




Thank you very much, Mr. Musk. See:

The Coming SSTO's: Falcon 9 v1.1 first stage as SSTO, Page 2.
http://exoscientist.blogspot.com/2013/11/the-coming-sstos-falcon-9-v11-first.html


Bob Clark

Edited by Exoscientist
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[quote name='Rthsom']I would like to see this be proven true. Launching a first-ever SSTO would certainly be a huge accomplishment.[/QUOTE]

While I agree it would be cool, there have been other rocket stages that would have been able to go SSTO. The Saturn V second stage comes immediately to mind, and if I recall correctly, I think the Atlas could have done SSTO instead of it's 1.5 stage design if it just used it's sustainer engine (but only just).
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Not much reason you'd want to. I guess if you were desperate for habitat structure for wet workshops you could do so, but have fun living in a house that smells permanently like kerosene.

Also, wow, I remember you from NASASpaceFlight. Still chasing the proverbial good SSTO design, I see. Edited by NovaSilisko
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Also, according to "Halfway to Anywhere: Achieving America's Destiny in Space" by G. Harry Stine (1996) these stages all had SSTO capability:

Ariane 5 Stage 1 (mass fraction 0.912)
Atlas E (mass fraction 0.933)
Black Arrow Stage 1 (mass fraction 0.922)
Delta 6925 Stage 1 (mass fraction 0.944)
Energia core (mass fraction 0.907)
Saturn IB Stage 1 (mass fraction 0.907)
Saturn IB Stage 2 (mass fraction 0.913)
Saturn V Stage 1 (mass fraction 0.941)
Saturn V Stage 2 (mass fraction 0.927)
Saturn V Stage 3 (mass fraction 0.905)
Titan II Stage 1 (mass fraction 0.966)
Titan II Stage 2 (mass fraction 0.908)
Titan III Stage 1 (mass fraction 0.948)
Titan III Stage 2 (mass fraction 0.923)
Titan IV Stage 1 (mass fraction 0.947)
Zenit Stage 1 (mass fraction 0.903)
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What's the point? Just to say that it can? Or could you actually take a small satellite. A cube sat. And launch it to orbit on the first stage? I imagine engines would have to periodically shut down to the last one to manage twr. That'd be pretty cool actually.

Seems like a waste though. Couldn't a much smaller, cheaper multi stage rocket do the same?
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[quote name='Motokid600']What's the point? Just to say that it can? Or could you actually take a small satellite. A cube sat. And launch it to orbit on the first stage? I imagine engines would have to periodically shut down to the last one to manage twr. That'd be pretty cool actually.

Seems like a waste though. Couldn't a much smaller, cheaper multi stage rocket do the same?[/QUOTE]

Yeah that's exactly the point. It is pointless which is why nobody has done it with any of the other SSTO capable stages
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[quote name='Steel']Yeah that's exactly the point. It is pointless which is why nobody has done it with any of the other SSTO capable stages[/QUOTE]

Well then what's Elon hinting at here? "That it can" or "that it will"? They're not actually going to try this are they?
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Not to poke all the Musk fanbois too much, but this just looks like a media friendly soundbyte a few days after a BlueOrigin success. Just a little "Hey remember us?" for SpaceX to stay current in a very short-term memory world.

Sure if you take all the payload off, I'm sure a whole range of different rockets could be SSTO, there is no reason to do such a thing though.
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[quote name='NovaSilisko']Not much reason you'd want to. I guess if you were desperate for habitat structure for wet workshops you could do so, but have fun living in a house that smells permanently like kerosene.

Also, wow, I remember you from NASASpaceFlight. Still chasing the proverbial good SSTO design, I see.[/QUOTE]

Wet workshops would be exposed to vacuum before having air pumped in, so the keresene would be vented.
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There have been plenty of first stages that had enough dV to go SSTO with a negligeable payload. Musk is just being an ass because he got burnt by Bezos. The phallic-substitute waving is getting ridiculous.

Even if the F9 first stage did get to orbit, there is no way it could reenter and land in one piece. It simply doesn't have any reentry capability. Edited by Nibb31
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[quote name='Motokid600']Even so I'm willing to bet it would still wreak of fuel. There's no way every molecule of fuel would escape.[/QUOTE]
It's amazing how sensitive our noses are. You are correct that it would be pretty hard to make a tank stop smelling like kerosene.
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As people above me have said, an SSTO version of a launcher's first stage will have too little payload to be useful.

[quote name='Nibb31']Musk is just being an ass because he got burnt by Bezos.[/QUOTE]

He didn't get "burnt," landing a stage that has a higher horizontal velocity, and is much larger/taller (because it is the first stage of an orbital launcher) is still a much harder challenge.

(I'm just wondering, are you hoping for SpaceX to fail or something?) Edited by Pipcard
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[quote name='Steel']While I agree it would be cool, there have been other rocket stages that would have been able to go SSTO. The Saturn V second stage comes immediately to mind, and if I recall correctly, I think the Atlas could have done SSTO instead of it's 1.5 stage design if it just used it's sustainer engine (but only just).[/QUOTE]

Sure but the point is that they needed extra boosters. Quite many stages could do that if we had efficient second stage engines on them. If F9 can do it without additional booster power, now that's something.
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[quote name='Reddragon']Sure but the point is that they needed extra boosters. Quite many stages could do that if we had efficient second stage engines on them. If F9 can do it without additional booster power, now that's something.[/QUOTE]

Not true at all. A lot of first stages (and some second stage) historically could have done SSTO as they were, Falcon 9 is nothing new or special. Edited by Steel
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A single stage to orbit rocket basically needs two things:

- A TWR on the pad >1
- A combination of fuel/mass ratio and engine Isp that yields the necessary ~ 9km/s dV

For example, an average Isp of 300 and a fuel mass fraction of 90%:

dV = 9.807 * 300 * ln(100/10) = 6774,4 <--- not enough

But make it ~400 average, like an RS-68 would have, and something like 92%:

dV = 9.807 * 400 * ln(100/8) = 9907,9 <--- yep, that works!


I would say that most rocket first stages today fulfil these requirements, especially those flying fully liquid fueled. So yeah, this bit of "news" is not really special nor particularly surprising. I would have been more surprised if the F9 first stage was [I]not[/I] SSTO capable.
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[quote name='Pipcard']
He didn't get "burnt," landing a stage that has a higher horizontal velocity, and is much larger/taller (because it is the first stage of an orbital launcher) is still a much harder challenge.[/quote]

He sure is acting on twitter like he is butthurt, which is definitely immature.

Everybody here knows the order of magnitude of difference between orbital and suborbital. There is also an order of magnitude difference between BO's flight and previous rocket landings like DC-X, Armadillo, and Masten. There's no need to rub it in constantly.

BO achieved a perfect landing on their second attempt and is likely to reuse a rocket stage before SpaceX. It is a great achievement and they deserve congratulations.

[quote]
(I'm just wondering, are you hoping for SpaceX to fail or something?)[/QUOTE]

Nope, just observing objectively and not being a fanboy. I love what SpaceX is doing. I'm not keen on the hype. Edited by Nibb31
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[quote name='Streetwind']A single stage to orbit rocket basically needs two things:

- A TWR on the pad >1
- A combination of fuel/mass ratio and engine Isp that yields the necessary ~ 9km/s dV

For example, an average Isp of 300 and a fuel mass fraction of 90%:

dV = 9.807 * 300 * ln(100/10) = 6774,4 <--- not enough

But make it ~400 average, like an RS-68 would have, and something like 92%:

dV = 9.807 * 400 * ln(100/8) = 9907,9 <--- yep, that works!


I would say that most rocket first stages today fulfil these requirements, especially those flying fully liquid fueled. So yeah, this bit of "news" is not really special nor particularly surprising. I would have been more surprised if the F9 first stage was [I]not[/I] SSTO capable.[/QUOTE]

So...nothing in your equation mentions anything about the size of the rocket. Could someone build a small rocket (10 feet high or something?) that could reach orbit?
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