F9r and observations from the shuttle

[Superluminaut]

One of the problems with the shuttle program was the excessive cost and time necessary for each post flight orbiter inspection. Do you expect spacex will be plagued with the same problem?

As far as I know spacex has not proven the repeat reliability of its engines, or the whole first stage really. I know the two experimental prototypes where flown multiple times, but how much of the hardware was reused, and what kind of turn around cost was associated with it. Not to mention the second prototype failed. Getting your hardware back seems only half of the cost reducing solution. How much development has actually gone into making that hardware reusable, and how extensive of a process is that expected to be?

[xenomorph555]

It should be noted they have never retrieved a stage from space, it could be highly damaged.

[Bill Phil]

The shuttle was more of an upper stage than a first stage. Although the F9 is different, it's still got a lot to prove.

[ZooNamedGames]

It should be noted they have never retrieved a stage from space, it could be highly damaged.

The only rocket part in my knowledge that has been staged off of a rocket and reused is the Space Shuttle's SRBs. We know how dangerous they can be when taken for granted... So I personally say reuse is a waste. Money will bite them in the back. It's like reusing the 1st stage of a S5- the most expensive is the fuel- once that's done then you only have to worry about is the structure which is way safer and cheaper to leave to rot... or just recover it for melting THEN reuse the raw materials to form them into what you need.

[Streetwind]

As far as I know spacex has not proven the repeat reliability of its engines, or the whole first stage really.

Each engine is test-fired for its full mission duration after it completes production. It is then assembled into the first stage, and then the completed first stage is again fired for its full mission duration before being assembled into the full rocket. A few days before lauch, the fully complete rocket is then rolled out onto the part for a so-called static fire test, where the full countdown sequence is practiced. The engines ignited and brought to full flight pressure, but the rocket is never released. So when the time comes to launch a brand-new Falcon 9, the engines actually are already more than "two flights in", and the first actual launch is actually just the "third flight" in a manner of speaking, not the first. This is done because the "bathtub curve" of reliability is a thing that exists - a complex piece of technology is highly likely to fail right after production (due to production mistakes) and at the end of its operational lifetime (due to old age), but in the middle between these high failure zones is a low area with almost no failures.

I know the two experimental prototypes where flown multiple times, but how much of the hardware was reused, and what kind of turn around cost was associated with it.

All of the hardware was reused for both Grasshopper and Falcon 9R-Dev1 (individually, not across them), at least according to SpaceX statements. Now, whether or not that hardware was subject to refurbishment between flights, I cannot say...

Not to mention the second prototype failed.

It failed due to a software problem specific to the test platform (a blocked sensor port that had no redundancy, but does have double redundancy on a regular F9). The rocket stage hardware itself had no problems - in fact, even the never-tested-before self-destruct mechanism worked flawlessly

It should be noted they have never retrieved a stage from space, it could be highly damaged.

That's why I am pretty much expecting the stage that they may or may not recover from CRS-5 to not fly again anytime soon. The prudent course of action will be to take it back to the hangar and disassemble it to the last screw to triplecheck everything. But frankly, even the ability to do this checking will be a major step ahead, and the results are sure to be interesting (one way or another).

The only rocket part in my knowledge that has been staged off of a rocket and reused is the Space Shuttle's SRBs.

Technically the orbiter was staged off of the STS rocket But, I get what you mean. The shuttle SRBs are a poor example of reusability though, because while the parts were in fact flown many times - I think the boosters for the last shuttle flight still had some parts in them that were used in the first shuttle flight - the process to refurbish them was extremely involved. They landed relatively hard in saltwater, so they had to be taken apart (into several thousand pieces for each booster!), and every part was scrubbed down and checked for corrosion and damage. It took more work than it would have taken to assemble a brand-new booster from factory-fresh parts.

I think this is the part that Superluminaut is wondering about, whether SpaceX can avoid paying more for refurbishment than what a new rocket would cost. In this, SpaceX has the advantage of landing much more softly, and not landing in salt water. This can potentially allow them to skip refurbishment entirely... if, of course, they can prove that the stages actually return undamaged and in prime condition.

[magnemoe]

It should be noted they have never retrieved a stage from space, it could be highly damaged.

Stage does not reach orbital speed so it face lite heat during reentry. it don't spashdown so it take no damage from seawater.

[ZooNamedGames]

Each engine is test-fired for its full mission duration after it completes production. It is then assembled into the first stage, and then the completed first stage is again fired for its full mission duration before being assembled into the full rocket. A few days before lauch, the fully complete rocket is then rolled out onto the part for a so-called static fire test, where the full countdown sequence is practiced. The engines ignited and brought to full flight pressure, but the rocket is never released. So when the time comes to launch a brand-new Falcon 9, the engines actually are already more than "two flights in", and the first actual launch is actually just the "third flight" in a manner of speaking, not the first. This is done because the "bathtub curve" of reliability is a thing that exists - a complex piece of technology is highly likely to fail right after production (due to production mistakes) and at the end of its operational lifetime (due to old age), but in the middle between these high failure zones is a low area with almost no failures.

All of the hardware was reused for both Grasshopper and Falcon 9R-Dev1 (individually, not across them), at least according to SpaceX statements. Now, whether or not that hardware was subject to refurbishment between flights, I cannot say...

It failed due to a software problem specific to the test platform (a blocked sensor port that had no redundancy, but does have double redundancy on a regular F9). The rocket stage hardware itself had no problems - in fact, even the never-tested-before self-destruct mechanism worked flawlessly

That's why I am pretty much expecting the stage that they may or may not recover from CRS-5 to not fly again anytime soon. The prudent course of action will be to take it back to the hangar and disassemble it to the last screw to triplecheck everything. But frankly, even the ability to do this checking will be a major step ahead, and the results are sure to be interesting (one way or another).

Technically the orbiter was staged off of the STS rocket But, I get what you mean. The shuttle SRBs are a poor example of reusability though, because while the parts were in fact flown many times - I think the boosters for the last shuttle flight still had some parts in them that were used in the first shuttle flight - the process to refurbish them was extremely involved. They landed relatively hard in saltwater, so they had to be taken apart (into several thousand pieces for each booster!), and every part was scrubbed down and checked for corrosion and damage. It took more work than it would have taken to assemble a brand-new booster from factory-fresh parts.

I think this is the part that Superluminaut is wondering about, whether SpaceX can avoid paying more for refurbishment than what a new rocket would cost. In this, SpaceX has the advantage of landing much more softly, and not landing in salt water. This can potentially allow them to skip refurbishment entirely... if, of course, they can prove that the stages actually return undamaged and in prime condition.

Exactly my thinking. Just reuse the RAW materials or start fresh- its cheaper- its easier- and its more reliable.

[Armchair Rocket Scientist]

The only rocket part in my knowledge that has been staged off of a rocket and reused is the Space Shuttle's SRBs. We know how dangerous they can be when taken for granted... So I personally say reuse is a waste. Money will bite them in the back. It's like reusing the 1st stage of a S5- the most expensive is the fuel- once that's done then you only have to worry about is the structure which is way safer and cheaper to leave to rot... or just recover it for melting THEN reuse the raw materials to form them into what you need.

IIRC fuel is less than 1% the cost of a Falcon 9 launch, and it's already one of the cheapest rockets ever in terms of hardware. Likewise, the raw materials are relatively cheap. This is why nobody pulls the wreckage of spent rocket stages out of the ocean for recycling - some people in Kazakhstan apparently take apart debris from Russian launches for scrap metal, but the money they get off it is only significant for trying to feed a family, not for building another rocket - if it was enough to significantly offset the cost of a launch vehicle the Russian Government would scrap the stages themselves.

The vast majority of the cost of a rocket launch is technology and labor. Manufacturing a launch vehicle requires a lot of expensive machines, such as 3D printers that can print metals, friction-stir welders, and enormous milling machines that can make an isogrid pattern in a giant fuel tank. It also requires a lot of highly-skilled labor from the engineers and technicians responsible for building the thing. There's also launch-related infrastructure, such as the pad itself, the transporter that moves the rocket to the pad from the VAB, and the permanent fuel tanks that hold the fuel before it's loaded into the rocket.

Now, with reusability you also get recovery and maintenance costs for the vehicle. SpaceX plans to keep the former low by boosting-back to land near the launch pad, and the latter is dependent on the vehicle design. Maintenance costs are also dependent on flight rate. IIRC one of the reason the Shuttle was so expensive was because its flight rate ended up much lower than anticipated. This was partly because the shuttle took forever to refurbish, but partly because they didn't have enough payloads since it turned out using a manned vehicle to launch satellites was economically moronic. With the Falcon 9, the question isn't whether people will want to launch satellites on it (they already do), it's whether the demand for satellite launches will increase enough when SpaceX lowers the price to make reusability economically viable.

[Superluminaut]

Each engine is test-fired for its full mission duration after it completes production. It is then assembled into the first stage, and then the completed first stage is again fired for its full mission duration before being assembled into the full rocket. A few days before lauch, the fully complete rocket is then rolled out onto the part for a so-called static fire test, where the full countdown sequence is practiced. The engines ignited and brought to full flight pressure, but the rocket is never released. So when the time comes to launch a brand-new Falcon 9, the engines actually are already more than "two flights in", and the first actual launch is actually just the "third flight" in a manner of speaking, not the first. This is done because the "bathtub curve" of reliability is a thing that exists - a complex piece of technology is highly likely to fail right after production (due to production mistakes) and at the end of its operational lifetime (due to old age), but in the middle between these high failure zones is a low area with almost no failures.

All of the hardware was reused for both Grasshopper and Falcon 9R-Dev1 (individually, not across them), at least according to SpaceX statements. Now, whether or not that hardware was subject to refurbishment between flights, I cannot say...

It failed due to a software problem specific to the test platform (a blocked sensor port that had no redundancy, but does have double redundancy on a regular F9). The rocket stage hardware itself had no problems - in fact, even the never-tested-before self-destruct mechanism worked flawlessly

That's why I am pretty much expecting the stage that they may or may not recover from CRS-5 to not fly again anytime soon. The prudent course of action will be to take it back to the hangar and disassemble it to the last screw to triplecheck everything. But frankly, even the ability to do this checking will be a major step ahead, and the results are sure to be interesting (one way or another).

Technically the orbiter was staged off of the STS rocket But, I get what you mean. The shuttle SRBs are a poor example of reusability though, because while the parts were in fact flown many times - I think the boosters for the last shuttle flight still had some parts in them that were used in the first shuttle flight - the process to refurbish them was extremely involved. They landed relatively hard in saltwater, so they had to be taken apart (into several thousand pieces for each booster!), and every part was scrubbed down and checked for corrosion and damage. It took more work than it would have taken to assemble a brand-new booster from factory-fresh parts.

I think this is the part that Superluminaut is wondering about, whether SpaceX can avoid paying more for refurbishment than what a new rocket would cost. In this, SpaceX has the advantage of landing much more softly, and not landing in salt water. This can potentially allow them to skip refurbishment entirely... if, of course, they can prove that the stages actually return undamaged and in prime condition.

That's a good point about the number of times spacex tests its engines. I wonder if they have a specified number of ignitions they build it for. Also I wonder if the low pressure environment during flight would cause additional wear and tear.

I have not yet heard about any planned infrastructure for vehicle inspections. I would assume they try to do it largely through on board sensors. Repair also raises a new issue to consider in the rocket equation. Would the additional mass of exchangeable parts be beneficial, or would it be more efficient to replace entire engines.