Battle of the Heavy Lift Rockets

schwit1 writes: Check out this detailed and informative look at the unspoken competiton between NASA's SLS rocket and SpaceX's planned heavy lift rocket. It's being designed to be even more powerful than the Falcon Heavy. Key quote: "It is clear SpaceX envisions a rocket far more powerful than even the fully evolved Block 2 SLS – a NASA rocket that isn't set to be launched until the 2030s." The SpaceX rocket hinges on whether the company can successfully build its new Raptor engine. If they do, they will have their heavy lift rocket in the air and functioning far sooner than NASA, and for far less money.

Why does it take so long?

[tekrat]

I mean seriously, look at the SLS, it's almost entirely composed of re-used space shuttle parts. It has the main engines on the bottom of the tank re-purposed from the shuttle. it has solid rocket boosters which already exist from the shuttle -- it entirely looks like it could be cobbled together in a few month's time because it uses almost entirely existing components.

So what exactly requires so many years to make it al work when it's all basically existing tech from the shuttle? I hate to say this, but this ain't rocket science.

Re:Competition is good.

[khallow]

You had a three sentence post and two of them were full of ignorance.

I was disabusing the previous poster of some pretty misguided notions. I guess you need some help as well. I notice, for example, that you don't actually disagree, you just choose to characterize my short observations as "full of ignorance". Do you have a reason why you think so?

I'm quite aware how NASA operates - by writing large checks to private contractors who make sure the money gets spent in the right congressional districts. But that sort of activity hasn't resulted in a viable launch platform since the 70s, when the Space Shuttle was developed.

And rather than continue to do something that hasn't worked in around four decades (and really, the Space Shuttle and the Apollo programs were just money sinks) maybe we could look at things that do work, like SpaceX's approach?

Re: Why does it take so long?

[kellymcdonald78]

While the "Shuttle Derived" messaging was used to sell the program, it's hardly anything but. The first few flights will use left over RS-25Ds from the shuttle program, but they are far too expensive for new ones to be built and throw away each flight, so the RS-25E and RS-25F engines needed to be developed. The 4 segment SRBs from the shuttle aren't powerful enough for SLS so they've had to develop a 5 segment SRB with a new type of solid fuel with a completely new grain. The casings are also being redesigned to be expendable. While the tank is shuttle derived, it needs a completely redesigned aft section to support the engines, plumbing is completely different, and the a new interstate to support the upper stage and payloads. It would have been cheaper and faster to start from scratch, but that doesn't keep the trough filled.

Re:Why does it take so long?

[petes_PoV]

So what exactly requires so many years to make it al work

It takes as long as it does, because that is the amount of time (or money: same principle applies) than is allotted to the project. Finishing sooner makes no sense as you'd just be working yourself out of a job earlier. There is also no pressing need to have such a vehicle. It's not as if there was a killer asteroid heading this way that would spell doom - and worse: upset NASA's carefully crafted timetables.

In that situation, where there was a deadline to be met (and not a vacuous political one), then yes: I daresay the prototype would be on the pad in a matter of months. With 2 or 3 more following close behind.

Re:No miracles

[0123456]

Efficiency is irrelevant when fuel makes up about 1% of the cost of a launch and bigger tanks are cheap. When you're throwing engines away every time, and they make up a large fraction of the cost of a launch, a low-cost engine that burns 10% more fuel can be a massive win.

Government rocket engineers have been fixated on efficiency because they rarely have to worry about cost. They can just steal more money from taxpayers.

Re:Competition is good.

[Anonymous Coward]

"Or paying a few tens of billions to develop a huge rocket " to who?

Boeing is the prime contractor for the design, development, test and production of the launch vehicle cryogenic stages, as well as development of the avionics suite.

TFA: "However, it is clear SpaceX envisions a rocket far more powerful than even the fully evolved Block 2 SLS â" a NASA rocket that isnâ(TM)t set to be launched until the 2030s."

The difference isn't private/gummint. All companies strive to make money.

The difference is in the objectives of the organizations involved. The objective of Congress is to get re-elected by keeping the pork flowing. The objective of Boeing is to take as long as possible to build anything because the longer it takes, the more pork flows in. Congress doesn't give a fuck if it ever flies. Boeing would be delighted if the project is funded to 2030, and even more delighted if cost overruns and delays pushed it out to 2050. Everybody has well-paid jobs for life!

The objective of SpaceX is Mars, bitches.

Musk needs an HLV long before 2030 if he is to live long enough to be able to retire on Mars. Because he is effectively self-funded, he not answerable to the whims of Congressmen and their pork allocations. Because he is interested in living long enough to see it fly, he is not interested in delaying things to pull as much pork out of the project as possible. He will build the fucking thing himself, and it will fly.