Charlie Bolden Is Very Confused These Days
Keith’s note: I am not sure what to make of this comment by Charlie Bolden. Either he is very confused or someone is giving him really stupid talking points. Let’s see, where do I start: how “old” is SLS technology? The Solid Rocket Boosters SLS uses are stretched and improved versions of the same design that Space Shuttles flew beginning in 1981 – but were designed in the 1970s (source). Oh, and SLS uses re-flown Space Shuttle Main Engines (RS-25) which were also designed in the 1970s (source). And, FWIW Bolden flew these vehicles multiple times in the 80s.
SpaceX vehicles and engines were designed in the 21st century, use advanced manufacturing technology and require an ever-shrinking number of people to launch. Instead of re-using the reusable SSMEs on SLS, NASA will throw them away whereas SpaceX can use their first stages over and over and over again – after they wash the soot off the rocket, that is.
Board member: why is NASA developing SLS when SpaceX has heavy-lift plans? Boldne counters that SpaceX’s Falcon 9 uses “old technology.”
— Jeff Foust (@jeff_foust) April 26, 2016
What a bizarre excuse. He could have said something like “NASA needs tried-and-true heavy lift capability and SLS offers more than a Falcon Heavy”, which would have been true at least in the case of the latter (SLS’s many, many other problems aside).
That wouldn’t even require him to say the real reason that SLS is being developed, which is that it’s what NASA’s backers/funders in Congress want.
It could be that Bolden very much deserves being jumped on. However, given the books that have come from departed Obama cabinet secretaries and functionaries, maybe we should all be kind and wait until Charlie writes his tell-all tome?
Not much “to-Tell” that would not be self-incriminating
Cut him some slack; he was probably thinking of the pintle injector on the Merlin and the fact that its a LOX Kerosene booster with an isp of about 360 seconds; the RS-25s are LOX H2 – and about 468 seconds – therefore the SLS engines are more efficient even though they are not going to be reused – which is definitely a SpaceX technology advance. Its probably an open question on whether you should reuse SLS boosters; if you’re launching once every year or two, the refurbishment costs and infrastructure might not be worthwhile; RS-25s have already proven reusability as part of the Shuttle program but the economics of the shuttle solids re-use never really lived up to its promise – you need higher flight rates to justify that. Falcon 9 can be reused a lot – for multiple missions and multiple customers; Musk’s dreams of Mars transporters ferrying lots of colonists to the red planet notwithstanding, its going to be a long time before the flight rate for a big rocket to do exploration makes sense.
ISP is a terrible yardstick these days. The cost of a launch (perhaps even divided by the payload mass) is a better metric to measure a launch vehicle by. This is especially true when comparing engines which use different fuels. Yes Merlin has a far lower ISP than an RS-25, but the Falcon 9’s kerosene tanks are far smaller in size and mass than if it burned LH2. Furthermore, the cost to manufacture a Merlin is a tiny fraction of the cost of an RS-25.
Here’s hoping that Falcon 9 continues to be successful and that Falcon Heavy starts test flights this year. Fly early, fly often.
ISP is the only yardstick that can be used, Merlin is 1/3 the thrust of RS25 but does not cost 1/3 the price of RS25
No. For first stage engines, thrust is more important than ISP. For upper stage engines, ISP is more important. The solids used to provide 6/7 of the thrust for the first two minutes. then SSMEs continued for another 6.5 minutes.
It is true that the SLS upper stage will have more efficient, altho more expensive, engines, than Falcon Heavy’s vacuum-nozzle Merlin. We will see how much Raptor improves on that, but LH2 will always be more efficient technically, even when you take into account the greater structural mass to hold the LH2 versus dense Kerosene or Methane.
But the only thing that should matter to us, since we are not spending our money, is cost per pound delivered to Mars orbit. By that definition Falcon Heavy is more efficient, even with a lowly kerosene upper stage.
Agreed, especially with, “the only thing that should matter to us, since we are not spending
our money, is cost per pound delivered to Mars orbit.”
any way you look at it, the efficiency of the engine is first and foremost, it doesn’t matter if the tank is 2000 gallons or 20000 if the energy per pound is the same (hydrogen wins)
the solids provided 6/7 of the thrust, but weight 2/3 of the total mass, at t-0, Saturn 5 didn’t have enough thrust to lift itself
either way, Falcon Heavy will require 27 engines, SLS only 4 and the two solids – which one is going to be cheaper?
SLS will be capable of lifting nearly twice as much as Falcon Heavy
Not sure why you say that at T-0 the Saturn did not have enough thrust to lift itself as it weighed 6.5 million lb and had a thrust of 7.5 million lb.
There is pretty good evidence, in the form of SpaceX pricing, that the Falcon Heavy will be considerably cheaper than the SLS. Even without reuse SpaceX has been able to reduce costs substantially. Two Falcon Heavy’s will probably be about 1/3 the cost of one SLS.
I got the Saturn V stuff from guys that built it, assembled it, hauled it over to 39A, fueled it, and watched it sitting there under full power of the five F1 engines for six seconds before the load cells on the hold down posts read zero
“Falcon Heavy will require 27 engines, SLS only 4 and the two solids – which one is going to be cheaper?”
Uh…SpaceX by about $800,000 per launch.
no, it will require two Falcon Heavy vehicles to put up the same payload as one SLS
Ok, then Spx will only be $650,000 cheaper
Just to be pedantic, the Boeing contract for SLS first stage cores is $1.4 billion each. Not including the engines, SRBs, upper-stage or payload. It’s unlikely that SLS would launch for less than $2b each.
SpaceX is offering commercial contracts for FH at less than $100m. Even assuming a 200% NASA-tax, you could still buy six FH launches for a single SLS launch.
You can probably trace all of the technology back to the V2 rocket if you wanted to, but Bolden shouldn’t have to defend SLS against SpaceX, since the competition is actually MCT. Does anyone think MCT will fly this decade ??
SLS won’t fly with people this decade either.
I’m expecting Elon Musk to reveal a ‘not earlier than’ date for MCT’s LCH4/LOX booster at the September announcement of his Mars plans.
BTW, it’s not just hardware SpaceX has developed, their innovative software is critical to their success.
Nobody ever accused Gen. Bolden of being a rocket scientist.
All I can ask is.. will Bolden be going bye-bye when we get a new president?
Almost certainly Charlie will be gone – he is tired if for no other reason. But it will take many months before the new President gets around to nominating a new Administrator.
Public: Why is Board member asking this question- now??
The idea was to re-use Shuttle tech, at least in part, as I recall, wasn’t it? Remember ‘shuttle-derived’?
You are correct about SLS, but SpaceX isn’t using revolutionary new technology either. I seriously doubt we can launch things without old fashioned rockets unless we can disturb the local Higgs field to make payload mass vanish.
BTW, the mass of ordinary matter is mostly (99%) from kinetic energy of quarks and gluons in the nucleons, not from the Higgs-derived mass of the quarks and electrons themselves.
The easier answer was that the Falcon 9H can lift 53 mt, while the SLS will lift 70 – 130 mt.
While not presuming to disagree with your sensibilities, I do have faith in the American electorate. There’s quite a bit of evidence that the craziness we see ensconced in the House is largely the result of district shenanigans and is not directly applicable to the electorate at large. I could be wearing blinders, though.
Your assessment that the choice between parties and the implications of victory by one side or the other is accurate, however. As a stalwart of one side I can only say that our candidate has lots of warts.
What a mess.