Blue Origin Thread (merged)

[Nibb31]

As I hadn't really been following Spacex until the last barge landing attempt

Well, then you might not want to get into an argument with people who have been following space new for years.

The point of reusability, as shown in all their old PR since they started working on reusability, implies flying back to the launch site, which is done by an RTLS burn after separation.

It has been admitted that reusability carries some heavy penalties:

- Additional fuel for the RTLS burn and landing (but remember that the stage is nearly empty at this point)

- A trajectory that is steeper, which adds less horizontal velocity in order to minimize the above

- A dV penalty that is transferred to the upper stage because of the suboptimal trajectory

- Additional avionics and attitude control systems to flip back the stage

- Additional weight for landing gear

Everybody recognizes that because of those penalties, the max payload of a reusable Falcon 9 will be several tons lower than a non-reusable Falcon 9, with something like 7 tons to LEO instead of 11 tons. So, only the smaller payloads will be able to benefit from the discount of a using a reusable first stage, but it is still within the margins of the launcher.

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Heck, even the 2nd stage is left with some excess fuel in it, because in the future they will re-use the 2nd stage too.

I doubt we will ever see 2nd stage reusability on the Falcon at this point. Maybe on SpaceX's next generation rocket, but it is a much tougher nut to crack than getting the 1st stage back.

[magnemoe]

I doubt we will ever see 2nd stage reusability on the Falcon at this point. Maybe on SpaceX's next generation rocket, but it is a much tougher nut to crack than getting the 1st stage back.

Wonder if they could use the return of engine only and capture in air technique ULA plans but here for upper stage?

Should have multiple benefits, upper stage is one engine and systems, is pretty light compared to first stage engines so its easier to capture

[SeaDog]

That is one possibility, but that will be for the BFR/MCT.

Another speculation for that vehicle I've seen is that the upper stage will be refueled in orbit, brought to mars, perhaps even landed and refuelled again and then used to bring back the MCT. Something along those lines. If anything remotely like that will happen is uncertain, but i guess it could count as reusability.

[Nibb31]

It would still need a heat shield for reentry, avionics, RCS for attitude control, and complex logistics to operate mid air recovery downrange in Europe or Africa (depending on the launch innclination), with all the ITAR strings attached.

All in all, it would still be much more complex than flying back the first stage. A single mass-produced Merlin engine is supposed to be pretty cheap compared to the rest of the rocket so I'm not sure that it makes sense to go to huge extremes to get it back.

I can't help thinking that it might be better to redesign the whole vehicle. Maybe you could make a reusable "Super Dragon" that would combine the second stage with the orbital vehicle, on top of a wider-base, lower-CG, reuse-friendly 1st stage. It would be a whole new launcher, a bit like a 2-stage version of DC-X, but it would be a great way to evolve SpaceX's current technology.

Edited April 18, 2015 by Nibb31

[magnemoe]

It would still need a heat shield for reentry, avionics, RCS for attitude control, and complex logistics to operate mid air recovery downrange in Europe or Africa (depending on the launch innclination), with all the ITAR strings attached.

All in all, it would still be much more complex than flying back the first stage. A single mass-produced Merlin engine is supposed to be pretty cheap compared to the rest of the rocket so I'm not sure that it makes sense to go to huge extremes to get it back.

I can't help thinking that it might be better to redesign the whole vehicle. Maybe you could make a reusable "Super Dragon" that would combine the second stage with the orbital vehicle, on top of a wider-base, lower-CG, reuse-friendly 1st stage. It would be a whole new launcher, a bit like a 2-stage version of DC-X, but it would be a great way to evolve SpaceX's current technology.

Second stage already needs RCS and avionics for satellite deployment. Added mass would be the decopler, heat shield and parachute, you will also want to put avionics and other expensive parts in the return module but leave most structure with the tank, you would also have some freedom in selecting reentry point doing burns after releasing satellites.

Benefit would be smaller heatshield and no need for fuel and legs for landing, you would also have more freedom in the heatshield design.

Main critic of the vulcan engine recovery is that it would be so heavy it would be hard for helicopters to recover but the falcon 9 upper stage is only 4 ton dry weight, now you drop the tank and most structure making it pretty manageable to capture.

Downside is that you could use aging engine for upper stage bringing the real engine cost down, this will also cost valuable payload capacity but so would any second stage recovery.

Was an earlier dissuasion about joining dragon and upper stage, main downside would be conflict between engine and heatshield, you would need an heatshield and structure going below the engine and an hatch for the engine to pass trough. In this case I wonder if an lifting body craft like an miniature shuttle design would be better.

This would have the option to use an drop tank like the shuttle used to keep size down.

[Motokid600]

Y'know last I tried landing a second stage in KSP I couldn't spin the craft back around to burn engines and land. The stage flew like a dart heatshield first into the ground.

Wonder how SpaceX planned on getting around that issue. The second stage has to reenter upside down and at some point right itself after heating.

Only thing I can think of is a parachute that deploys from the top near the heatshield just to spin it around.

[Lukaszenko]

No one here is an actual engineer, let alone an engineer at SpaceX.

You're making it sound like engineer= rockstar or Fortune 500 CEO

I'm actually pretty sure quite a few people here are "actual" engineers.

[PakledHostage]

No one here is an actual engineer, let alone an engineer at SpaceX.

Thanks. Now I'm having an existential crisis...

[StrandedonEarth]

Pic of debris-strewn JRTI in port!

http://spaceflightnow.com/2015/04/17/photos-spacexs-debris-strewn-landing-barge-back-in-port/

Note: SpaceX decided a while back that it's better to put resources towards developing Raptor than recovering the F9 second stage, so they're not bothering with that.

[magnemoe]

Thanks. Now I'm having an existential crisis...

Same here.

[wolfedg]

Well, then you might not want to get into an argument with people who have been following space new for years.

The point of reusability, as shown in all their old PR since they started working on reusability, implies flying back to the launch site, which is done by an RTLS burn after separation.

It has been admitted that reusability carries some heavy penalties:

- Additional fuel for the RTLS burn and landing (but remember that the stage is nearly empty at this point)

- A trajectory that is steeper, which adds less horizontal velocity in order to minimize the above

- A dV penalty that is transferred to the upper stage because of the suboptimal trajectory

- Additional avionics and attitude control systems to flip back the stage

- Additional weight for landing gear

Everybody recognizes that because of those penalties, the max payload of a reusable Falcon 9 will be several tons lower than a non-reusable Falcon 9, with something like 7 tons to LEO instead of 11 tons. So, only the smaller payloads will be able to benefit from the discount of a using a reusable first stage, but it is still within the margins of the launcher.

Well I wouldn't have called it arguing so much as questioning, but nevertheless your post answered a lot of the questions that were going through my head.

[AngelLestat]

But even if you can launch the half of the payload in full reusable mode, you reduce current spacex cost (which are already cheap) by more than a 90%, this counts for falcon 9 and falcon heavy.

There are many missions which you dont need the full payload.

[Leszek]

Question

What is cheaper a single non-reusable F9 with 11 ton payload, or a reusable F9 Heavy that has only an 11 ton payload?

[Nibb31]

But even if you can launch the half of the payload in full reusable mode, you reduce current spacex cost (which are already cheap) by more than a 90%, this counts for falcon 9 and falcon heavy.

There are many missions which you dont need the full payload.

You keep on waving around this 90% figure, as if SpaceX reusability will somehow reduce their launch price from $60 million to $6 million. We've already explained to you plenty of times that it doesn't work that way. The hardware is only a part of the launch costs. Most of those costs are fixed costs that do no benefit from reusability. The best SpaceX can hope for, with full reuse of the 1st stage, is 20%, which would bring the ticket price down to $50 million.

Also, there will never be "full reusability" of the Falcon 9. The second stage will not be reusable. It is very unlikely that the central core of the FH will be reusable before a long time, and there will still be many payloads that won't be able to afford the mass penalty of reusability.

Question

What is cheaper a single non-reusable F9 with 11 ton payload, or a reusable F9 Heavy that has only an 11 ton payload?

There is no reusable FH yet. Full reusability of the central core, which goes much higher and faster than the F9 core, is pushing expectations quite a lot. Since the central core will probably have to be expendable, the FH can't be cheaper than an expendable F9.

[Frozen_Heart]

Question

What is cheaper a single non-reusable F9 with 11 ton payload, or a reusable F9 Heavy that has only an 11 ton payload?

If they manage to get reusability on all 3 cores then in theory the Falcon Heavy could be cheaper. However the central core will be heading downrange very fast by the time of separation. They would need to land it on a barge as boostback would be too much.

[Nibb31]

If they manage to get reusability on all 3 cores then in theory the Falcon Heavy could be cheaper.

We don't know anything about the economics of a reusable F9 first stage yet. As I said earlier, there are fixed costs that are not proportional to the size of the rocket or launch rate. The biggest cost is the salary of the personel, not the launch hardware. Reusing hardware only saves a small part of the operation cost. The rest of the logistics, R&D, manufacturing and processing facilities, maintenance, payload integration, launch operations, mission control, etc... all remain the same. And the economics of reusing rocket stages goes against the economics of mass producing rocket stages, which has been how SpaceX has managed to reduce costs until now.

The industry will need several years of experience with reuse and higher launch rates before anyone can claim that it actually saves money. Currently there is no reason to believe that the demand for orbital launches will boom because SpaceX cuts prices from $60 million to $50 million.

However the central core will be heading downrange very fast by the time of separation. They would need to land it on a barge as boostback would be too much.

They also need to figure out how to make it survive reentry. The central core will be flying much higher and faster than an F9 1st stage. It will need some sort of TPS, and it might be going too fast to flip around without breaking up in the air stream.

Let's let them figure out recovering and reusing the easy stuff before speculating on stuff that is much more complicated. I'm not saying they can't do it, but it will require a serious R&D effort, which might not be economically worth it. There isn't much of a market for Falcon Heavy so it doesn't make much sense to spend a big effort on reusing the central core. Getting the side boosters back will already be quite an accomplishment.

[Pipcard]

I always see some people praising the idea of reusabiility. "Throw-away rockets are a waste! Why build a new rocket every time? Rapid reusability is possible! It is the future, and it will revolutionize space access!"

and then I see some people doubting it. "Maintenance will cost too much! Not enough launch rate/flight rate! What about mass production? The market isn't big enough!"

But which one will be true for SpaceX? We'll just have to find out. They probably know about the lessons learned from the Space Shuttle, and are applying them to the Falcon 9. For example, their launch system doesn't involve 35000 tiles on a large winged orbiter that need to be inspected individually.

Edited April 19, 2015 by Pipcard

[Frozen_Heart]

They also need to figure out how to make it survive reentry. The central core will be flying much higher and faster than an F9 1st stage. It will need some sort of TPS, and it might be going too fast to flip around without breaking up in the air stream.

I assumed that rather than doing a boostback, it would simply use excess fuel to slow down to a speed more similar to a Falcon 9 first stage before re-entering. As its so large it should have extra fuel for at least that.

[YNM]

Is it a thing to save the boosters using only/partially using chutes or so ? (or maybe help the landing a bit with chute, much like the how they plan on the capsules)

[Pipcard]

Chutes mean less landing accuracy, which will make recovery and rapid reusability harder compared to a precise propulsive landing.

Also, there will need to be large parachutes for a large stage, which will add a lot of weight.

Edited April 19, 2015 by Pipcard

[Nibb31]

Is it a thing to save the boosters using only/partially using chutes or so ? (or maybe help the landing a bit with chute, much like the how they plan on the capsules)

Boosters are heavy, so you would need super-huge parachutes, which aren't precisely cheap. Salt water is also corrosive and damages engines, which means they would need to be stripped down and cleaned. Also, even with a parachute, a splashdown is a violent process. The Shuttle SRBs were recovered after parachuting down into the Atlantic. They were steel casings, much stronger than aluminium tanks, and they still got severely damaged and bent in the process.

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I assumed that rather than doing a boostback, it would simply use excess fuel to slow down to a speed more similar to a Falcon 9 first stage before re-entering. As its so large it should have extra fuel for at least that.

It still needs to flip around at hypersonic speeds to do a retro-burn. That might be possible, but it might not. It's still another nut that needs cracking.

[AngelLestat]

Question

What is cheaper a single non-reusable F9 with 11 ton payload, or a reusable F9 Heavy that has only an 11 ton payload?

THey comment that for the first stage core/booster reusability an 11 tons launch will be still cheaper to use a falcon9 without reusability. That is because in the falcon heavy they still have problems about how to recovery the center core stage.

You keep on waving around this 90% figure, as if SpaceX reusability will somehow reduce their launch price from $60 million to $6 million. We've already explained to you plenty of times that it doesn't work that way.

When you said "we" you mean shynung and you?

I (and some others) also explained lots of times why your logics and calculations are wrong. At this point when we both already propose our arguments and we find not agreement, the only we can do is wait and see who was right.

About how much it will take to reduce the cost when they achieve to recovery the first stage/boosters, almost right away if their chances of success are high.

This is because even if you dont need to reduce the prices much, they will do it anyway to the max they can for two reasons.

1- To show everybody they did what their promise, also this it will mean a clear evidence for investors that is a safe bet being so far from the competence and with good chances to control the space market in not time. This will produce also a lot of losses to their competence which it will be harder to reach them.

2- To encourage new bussiness oportunities in space and increase by a lot the amount of launchs by years, which is equal to how fast you can progress and reduce the cost even more.

Also, there will never be "full reusability" of the Falcon 9. The second stage will not be reusable.

Never said never.. Never in this case means 5 years for the first tries or plan.

It is very unlikely that the central core of the FH will be reusable before a long time, and there will still be many payloads that won't be able to afford the mass penalty of reusability.

I never said that any kind of payload will have those prices. But if for certain type of payload you get great discounts, then everybody will start to designs spacecrafts to fix those payload margins.

Is it a thing to save the boosters using only/partially using chutes or so ? (or maybe help the landing a bit with chute, much like the how they plan on the capsules)

I guess 3 short rotor blades at the side of the booster will full fill the fins duty even better and will provide much more control and chances to a soft landing using the autorotation effect. This also reduce the amount of fuel waste it.

Like this but with shorter blades

Edited April 19, 2015 by AngelLestat

[Nibb31]

I (and some others) also explained lots of times why your logics and calculations are wrong.

No you haven't. You have waved away the economical and industrial factors or used wrong assumptions on how the space industry works.

You keep on bringing up unrealistic figures like "90% reduction". That implies that the first stage hardware represents well over 90% of the total launch cost, which completely ignores all the other costs involved. In reality, it might represent 60% of the total rocket, while the rocket hardware itself only represents maybe 30% of the total launch cost.

[shynung]

When you said "we" you mean shynung and you?

Shall I remind you of this particular thread? Me and Nibb aren't they only ones who have problems with the concept.

Edited April 19, 2015 by shynung

[sgt_flyer]

@shynung one of the possibilities for the tip over, would be that either one leg broke due to the horizontal speed, or failed to deploy / lock itself in place correctly. when the booster immobilize itself, it looks like already slightly tilted in.