Falcon Heavy

[Rockhem]

The Falcon Heavy

What do you guys think of the Falcon Heavy?

Personally, i think that it will be a great thing, to take heavy payloads to LEO and possibly, with a light enough payload, and beyond.

SpaceX has said that the cost per pound to get on the Falcon Heavy will be around $1000 dollars. The Falcon Heavy uses a little thing we

like to call "Asparagus Staging" which allows the boosters to pump fuel into the central stage.

LEO

To LEO, it can take 53 metric tons! That is a whole lot of mass! It will enable cheaper spaceflights, and is actually past the concept stage!

The Falcon Heavy is quite a small spacecraft for it's capability. The spacecraft is also pretty cheap at 80-125 million dollars.

Beyond Earth Orbit

The Falcon Heavy could probably put payloads into TLI and TMI (trans martian injection) quite easily, although it would of course be less than it's payload the LEO.

This could open up possibility of low cost microsats (making up names here) that would be bigger than a cube sat but smaller than a regular one that could be launched for

several hundred thousand (assuming that the rocket has enough buyers to fill it up) each.

Closing

I think that the Falcon Heavy will further spaceflight, and push the industry ahead. What are your thoughts?

[AustralianFries]

Looks great. Fairly decent production cost, one hell of a lifter, and the LEO is a bonus.

Guys, check this out!

[nettcod]

Low-cost heavy lifting? Hell yeah.

Edited January 22, 2014 by nettcod

[Bioman222]

Man, I am so impressed that just a commercial company could get this far.

[Klingon Admiral]

I still wonder how such a lifter will be commercially viable, as the only customers who need this lifting capabilities are national space agencies (to be more specific: NASA), and we all know where the budget of most space agencies is heading. And then, with that many engines, there is a lot of error potential. So in short, quite an overengineered beast.

[NovaSilisko]

I still wonder how such a lifter will be commercially viable, as the only customers who need this lifting capabilities are national space agencies (to be more specific: NASA), and we all know where the budget of most space agencies is heading. And then, with that many engines, there is a lot of error potential. So in short, quite an overengineered beast.

Heavy stuff in geosync orbit is big business too. That's the prime business driver behind FH, I believe. That, as well as launching lots of smaller satellites from one vehicle (Ariane 5 routinely launches 4+), enabling everyone to split the cost.

Multiple-engines does have a lot of error but they're designing their systems to be tolerant of errors (this was demonstrated on the CRS-1 flight when the center engine failed and possibly disintegrated). The Merlin engines are also designed to be simple, which reduces the per-engine failure risk.

It's a tradeoff, though. Three big engines with good reliability would work as well, but if you lose just one, you lose the vehicle.

Edited July 11, 2013 by NovaSilisko

[Alfastar]

Well, when most says the Falcon Heavy is great, I say that its now useless and not cheaper then a dual GEO payload launch from a Ariane 5.

Why? Because the Falcon heavy don't got a dual payload system. The Ariane 5 got. If you count already the launch cost for the Falcon heavy (What is not really trustful) then it MAY be cheaper in the first place, but around the same price, you can launch something from the Ariane 5 with a dual payload system.

And would so much engines be not even more risky? How more engines, how more chances that something can be wrong.

[harbingerdawn]

And would so much engines be not even more risky? How more engines, how more chances that something can be wrong.

Wrong. More engines means that the vehicle can survive an engine failure and still complete its mission. See Falcon 9 Flight 4 (SpaceX CRS-1 mission) and SA-508 (Apollo 13 mission) for proof.

Because the Falcon heavy don't got a dual payload system

Why do you assume that it could not use a dual payload system? I see no reason why one could not be developed.

[metaphor]

The Falcon Heavy needs to get a new upper stage to be more competitive in GEO launches. It might have a 53 ton capacity to LEO, but only 12 tons to GTO (partly because it's using a low Isp kerosene upper stage). For comparison, the Delta IV Heavy can only get 23 tons to LEO, but 13 tons to GTO.

The Falcon Heavy is still going to be cheaper than any competitor to GTO (where most of the commerical demand is), but not by that much. We'll have to wait and see how it performs on its test launch next year.

[Nibb31]

Man, I am so impressed that just a commercial company could get this far.

Powerpoints are easy. I will be impressed when it flies. ULA also have Powerpoint versions of ultra heavy evolutions of Atlas and Delta, just in case the need ever arises for large payloads. That doesn't mean they will ever be built.

However, SpaceX has all the hardware already. They should be able to build it if they ever get a launch contract. And that is the crux of the matter. SpaceX is a launch provider, not a space program. They launch stuff that other people pay for, and there is currently nothing for this to launch.

Commercial comsats are usually based on standard satellite busses, which are sized for current comsat launchers. Commercial operators are not interested in building larger comsats, especially as the need for GTO comsats is probably going to decrease in the near future as satellite TV is being replaced by broadband TV and 4G. Also, larger birds cost more if they fail. So I don't see them ever wanting a >30t comsat in GTO.

Government organisations will not design any payloads specifically for F9H until it has a proven flight record and they would need a backup plan. If for some reason the F9H program was to be cancelled, they would have an expensive 50t bird and no launcher to send it up with.

And no, SpaceX is not going to Mars unless someone pays them to. NASA certainly has no plans for that, and I don't see any other credible plans for that.

[DerekL1963]

Wrong. More engines means that the vehicle can survive an engine failure and still complete its mission. See Falcon 9 Flight 4 (SpaceX CRS-1 mission) and SA-508 (Apollo 13 mission) for proof.

No, he's quite correct - more engines mean more things to go wrong. That's a basic engineering fact. They also require more plumbing and a more complex and heavier thrust structure. But smaller engines are cheaper and simple to develop and build, so SpaceX is making lemonade out of lemons because modern engines fail very rarely. (Well, rarely by rocketry standards anyhow. By the standards of pretty much any other field of engineering they're pretty much crap.) The Shuttle, for example, suffered two engine failures out of 405 engine-flights. (If the Merlin engines of the Heavy fail at the same rate as SSME's, SpaceX can expect to lose an engine roughly every 8 flights.)

Other than that, let's wait and see if it ever flies.

[Klingon Admiral]

Heavy stuff in geosync orbit is big business too.

Which heavy stuff exactly? The GTO payload of the Falcon 9 Heavy is comperable to the payload of the Ariane 5, which currently holds the lion's share of the commercial launch market, no matter how hard Mr Musk tries to trashtalk them. Of the 69 Ariane 5 launches, only 12 carried a single payload, the 3 ATV launches included. 3The rest where launches of 2 or more satellites, with one ocassion where 7 satellites where lifted in one go. So even the Ariane 5 is quite overengineered for the work that it is doing.

Wrong. More engines means that the vehicle can survive an engine failure and still complete its mission. See Falcon 9 Flight 4 (SpaceX CRS-1 mission) and SA-508 (Apollo 13 mission) for proof.

Neither Falcon 9 #4 were nor Apollo 13 were sucessful missions. The secondary payload of the Falcon 9 could not be inserted into a proper orbit and was therefore lost. And what did Apollo 13 have to do with engine failures, especially engine failures on the first stage? In fact, was there any completely sucessful launch after an engine failure? Rockets aren't build with much room for error.

[andrewas]

Apollo 13 was successful after an engine failure, in that the loss of the second stage center engine had no major effect on the mission. The second and third stage burns were extended to compensate, and the mission went on as planned until an unrelated catastrophic failure in the oxygen tank in the service module.

Falcon 9 #4's secondary payload was deliberately aborted by NASA, as the extended burn to get the first payload into orbit eliminated the safety margin required for the secondary orbit. The mission could almost certainly have been done, but NASA were unwilling to risk the payload failing to clear ISS altitude.

Falcon 9 Heavy should perform even better if it loses a first stage engine, since thats a smaller portion of the overall thrust, which is the point that was made. The more engines you have, the more chance you have of one failing, but the less the impact that one failure has on the mission. Fly on one massive engine and either it works or it fails catastrophically, fly on 27 and you are much more likely to get into a useable orbit.

[Nibb31]

On the other hand, if you are flying 27 engines but you could succeed the mission with only 24, then you are have 3 engines on your rocket that are dead weight. In the case of the SpaceX Merlin, that's 2 extra tons of payload that you could be carrying instead.

If you have 2% failure rate on a single engined rocket, then you have 1 mission failure every 50 flights. If you have the same failure rate on a rocket with 27 engines, then you can expect at least one engine failure (which might mean degraded performance or loss of a secondary payload) every 4 flights.

It was a long time since I did any probability calculations, but you can also extrapolate that the figures for a double or triple engine failure (in which case you might lose the mission) are not negligeable.

Edited July 11, 2013 by Nibb31

[metaphor]

A 2% engine failure rate on a rocket with 27 engines means a 42% chance of at least one engine not working on any one flight. (98% chance of an engine working ^27 = 58% chance of all of them working)

The chance of at least 2 engines failing is 10% on any one flight. (98% chance of an engine working ^26 * 2% of one engine not working * 27 combinations = 32% chance of exactly one engine not working)

The chance of at least 3 engines failing is 1.5% on any one flight. So if the mission can be completed with the loss of 2 out of 27 engines, that's already better than using a single engine with a 2% failure rate.

[Kryten]

It depends on which two engines. Two on the same side could potentially cause mission failure for Falcon 9, and I'm not sure it's different for heavy. It'd certainly cause severe issues if it happened on the centre core.

[Klingon Admiral]

On the other hand, if you are flying 27 engines but you could succeed the mission with only 24, then you are have 3 engines on your rocket that are dead weight. In the case of the SpaceX Merlin, that's 2 extra tons of payload that you could be carrying instead.

If you have 2% failure rate on a single engined rocket, then you have 1 mission failure every 50 flights. If you have the same failure rate on a rocket with 27 engines, then you can expect at least one engine failure (which might mean degraded performance or loss of a secondary payload) every 4 flights.

It was a long time since I did any probability calculations, but you can also extrapolate that the figures for a double or triple engine failure (in which case you might lose the mission) are not negligeable.

Couldn't even a single engine failure result in a mission loss/double engine failure. I mean if it isn't the central engine that fails to ignite or whatever can happen to such an engine, wouldn't the loss of an engine result in the center of thrust shifting away from the center of mass, creating all sorts of nasty imbalances, besides the booster tanks not draining fuel at the same rate. Depending on how the ropcket can deal with such events, it might be necessary to shot down the "mirror-engine" of the engine that failed, if this is even possible.

[Bunsen]

Couldn't even a single engine failure result in a mission loss/double engine failure. I mean if it isn't the central engine that fails to ignite or whatever can happen to such an engine, wouldn't the loss of an engine result in the center of thrust shifting away from the center of mass, creating all sorts of nasty imbalances, besides the booster tanks not draining fuel at the same rate. Depending on how the ropcket can deal with such events, it might be necessary to shot down the "mirror-engine" of the engine that failed, if this is even possible.

The shift in center of thrust usually falls within the engines' gimbal range -- the remaining engines just readjust so the net thrust still points through the center of mass. It's more complicated if it happens early in the flight, because that shift also changes the angle of attack and then you have to account for aerodynamic effects too. On an outboard booster, propellant leveling might require shutting down a counterpart on the opposite booster, but maybe there's enough control in the crossfeed system to handle that.

The other problem is the risk of an engine failing violently enough to damage its neighbors or their plumbing. I know the Falcon 9 has some compartmentalization to address this. I don't know how violent an event it can handle, nor how far down the probability scale such events are.

[Alfastar]

Wrong. More engines means that the vehicle can survive an engine failure and still complete its mission. See Falcon 9 Flight 4 (SpaceX CRS-1 mission) and SA-508 (Apollo 13 mission) for proof.

A very simple fact is that how more stuff you put into something, how more change is that one of them going fail. 27 engines are just much, maybe too much. You can say that it can handle a engine failure, but would you as commercial company will launch you sat into GEO by a rocket who engine(s) fails at 50% of the flight history? (This is much more theoretical, but I try to let you understand my point)

Why do you assume that it could not use a dual payload system? I see no reason why one could not be developed.

Well, I not saying that it can't use a dual payload system. I saying that its not really profitable if it don't got it. Would be it not even just useless to make a commercial heavy-lift rocket without having a dual-payload system.

[stupid_chris]

I'm pretty damn sure the engineers at SpaceX are aware of the potential failures and if they keep the nine engine per booster configuration of the falcon 9, I think it's because they know what they're doing huh?

[jwenting]

redundancy is always a good thing. Engines are cheaper than payloads, and if they can shave 20% from the cost of an engine per KN thrust by using multiple smaller engines, each of them 1-2% less reliable than a single big one, they can easily compensate for needing more engines as they can use an extra 20% total thrust before it costs them money, leading to a rocket that's in total more reliable.

[DerekL1963]

I'm pretty damn sure the engineers at SpaceX are aware of the potential failures and if they keep the nine engine per booster configuration of the falcon 9, I think it's because they know what they're doing huh?

They could also be keeping them for the same reason I once drove a crappy car for years, it's what I had and what I could afford. Just because they keep it, doesn't mean it's optimal. SpaceX is, like anyone else, limited by schedule and budget.

[Nibb31]

redundancy is always a good thing.

No it isn't. Redundacy adds weight and complexity and cost. More stuff on board = more stuff that can go wrong. There is a balance to be found between redundancy, reliability and cost. That's Engineering 101.

The Apollo LM Ascent Stage engine was one of the single mission critical systems with no redundancy, which if it failed, the astronauts were lost. It would have added weight and complexity. Instead, they made it as simple and fault-proof as possible. They used hypergolics (which ignite spontaneously) to minimize moving parts, and put the engine under a cover that was accessible from inside the LM, so that if a valve got stuck, the crew could bang on things to get it to work.

They could have added redundancy, but they didn't because redundancy isn't always a good thing. Instead of redundancy, they opted for robustness and simplicity.

In the case of the Falcon, SpaceX engineers are not stupid and I'm pretty sure they have done the math regarding failure probabilities, but in the end, the main driver for using 9 Merlin engines is economical. Their aim is to make cheap rockets, and the cheapest engine is the one that you already have on the shelf.

[Fuzzy Dunlop]

I'm completely guessing here but I think the Merlin's physical size is probably a signifcant issue. Rocket engines are complex machines which take many man hours to build, this would only be exacerbated by having a huge, unwieldy structure. Merlin is slightly taller than an average man and weighs about 700 Kg, one guy can push it around on a trolley, I'm guessing most components can easily be lifted and installed by hand, everything is easily accessible. Overall I think you would need far more faffing with about cranes, jacks and scaffolding if you were building a much larger engine, which costs time and money.

[Dkmdlb]

Regarding the large number of engines causing reliability issues, I give you the most successful, reliable space launch system ever developed by human kind:

And now the most expensive failure ever, the N1: