No, the claim isn’t small vs large, it is reusable vs expendable. RLVs could be an order of magnitude more efficient than expendables. Smallness only has to do with lower development costs making it easier to get funding and and smaller size making it easier to get a very high flight rate, which is also required to achieve drastically lower costs. Small RLVs are going to be economically viable much earlier than large ones and they would be good enough to allow significant commercial manned spaceflight and large scale government funded exploration.

“he seems to be afraid”

“Afraid” is not exactly the right word, “extremely concerned” would be much much better.

“of dead comet cores with a such a low albedo that they’re not easily detectable by optical systems. Best way to find them is observation in the infrared, which can’t be done well from earth for obvious reasons.”

Its “comet fragments”, not “comet cores”, and those and Long Period Comets, and Moon based instruments provide another 6 months to deal with a LPC inbound our way, not to mention much better detection of all of the smaller stuff.

“if I remember the general consensus correctly- should serve to make such encounters exceedingly unlikely.”

You got theories, and then you got facts.
When the two diverge it is time for a new theory.

“I’m also not aware of any geological evidence that this is a serious threat, unlike asteroids.”

Well, you’ll have to do some reading then.

I also hope you can find NASA’s CAPS studies online.

Sorry for not providing you with a hole bunch of handy dandy easy links, but I didn’t see your post earlier, its late, and I’m going to have some dinner and then sleep

While my guess is that to do so for you would be futile, others here might benefit. On the other hand, they might already be smart enough to use search engines.

E.P. Grondine
Man and Impact in the Americas

spacenews.com/commentaries/110418-misplaced-priorities-congress.html

FWIW…

Who has said this? Specifically? Quote? Reference?

Don’t lie.

I and other folks have stated several times in this forum that for NASA, it makes no sense to spend limited taxpayer dollars on a special-purpose HLV until absolutely necessary. Existing, underutilized LVs whose costs have already been paid for should be maximized first and limited development dollars should go into new in-space propellant management and storage capabilities first.

But the F9H is being paid for by SpaceX and its investors, not NASA or the taxpayer. It’s up to their corporate leadership to determine what markets they want to go after, what capabilities those markets require, and whether it makes sense to invest in those capabilities. If they think a lighter weight and highly efficient HLV is the best way to knock out the Delta IV Heavy and undercut the overall market for Ariane V, Proton, and EELVs, then that’s their decision.

I hope NASA, Congress, and the White House are smart enough to leverage the F9H instead of wasting my taxpayer dollars on a duplicative HLV when private industry plans to pays for this one. But aside from that, SpaceX’s decision to fund F9H has nothing to do with NASA or my taxpayer dollars.

“That is a no-brainer, and I know from you all have something between your ears, whether or not you agree… It almost looks to me like you guys just happend to like Mr Musk, and anything he does is OK in your book. If, hypothetically, he was a lemming, I fear that one or two of you might almost be tempted to follow suit”

I fear you can’t make a post without repeating lies, insulting other posters, and calling them names.

Take your crap elsewhere.

Cripes…

“It is funny how I heard people claim that only small rockets are efficient.”

I haven’t heard that claim. What I have heard & stated is that mega-launchers that Congress & NASA want to build don’t come close to being cost effective unless you have to put up lots of mass (over 20M lbs), and if there is that much mass needed, then commercial companies would do it better and cheaper.

And then SpaceX announces the F9H, which has a lower cost per payload pound to LEO than the F9.”

Which like all privately funded business ideas, could be just what the market will need, or not. But the great thing is that the U.S. Taxpayer doesn’t have to pay for it’s failure, and it can benefit from it’s success. Capitalism at it’s best.

The SLS on the other hand only makes sense if there is a huge funded need for it, and so far there is ZERO.

You know, some in Congress have this idea that because NASA has always launched it’s own stuff on the Shuttle, that that is the way it should always be.

But consider this. When Apollo first started, there was no significant commercial launch industry, nor was there much of one in the 70’s when the Shuttle was conceived and built.

Today though we have a plethora of launch capability, both within the U.S. and with our political allies. If the U.S. needs to put mass into orbit, there is plenty of excess capacity available today to do it, and more that can be added in a couple of years by expanding existing facilities.

Without a defined and long-term need, the SLS is not needed. The Falcon Heavy may not even be needed, but like I said, if it fails, then the taxpayer doesn’t have to pay. With the SLS, it will be a $20B+ failure.

I could buy a car to drive myself to the airport or I can rent a car, or I can use public transport. Using public transport is much cheaper than buying a car. Renting a car is cheaper than buying a car.

The only reason why it makes any sense for me to own a car is becuase I intend to use it a lot and use it for task that public transit is not as well suited.

If I only drove 4-6 times a year like the shuttle flies or the 2 trips to the moon that Apollo did it makes no sense to own a completely separate system. The fixed costs of running said system will eat any savings from having your own system.

First, I would challenge the notion that Falcon 9 is a small rocket (or the Atlas V, or Delta IV)

Second – the issue, IMHO, isn’t about HLVs vs non-HLVs. The biggest issue are market segmentation vs market growth. Fundementally, (which I think you’ve mentioned before) we need to grow the markets for launch vehicles. The reason like propellant depots is they are inherently a market creator – fuel can be fairly launcher agnostic. Or, on another side – multi-core based HLVs don’t bother me, because they increase the utilization of existing rockets, and don’t produce specialized, highly expensive systems (assuming Elon can back up his numbers, he’s talking about producing 40 cores a year – that would have to producing some interesting results). And no, I don’t just limit this to Falcon 9 – I have no problem with Atlas V Phase 1 or 2, or Delta IV growth (provided we aren’t talking about something highly specialized)

Alternatively, if you produce a vehicle that has no payloads, that means you are using money to develop something that doesn’t have a purpose to fly (IE Senate Launch System) or you are creating a rocket to launch something that doesn’t need a new rocket (Ares I) you are increasing market segmentation or at least decreasing the market growth. These are bad things

When it comes to things like HLVs, prop depots, and other tech/vehicle development

“I don’t wish to follow the M1 analogy too far.”

to follow it at all is goofy and not a comparison that has any validity. There is a reason for the US government to have assets which are unique to a particular mission that it needs done; but if that is the case then the mission itself is what should bear scrutiny FIRST and then the hardware being capable of accomplishing that mission is next.

At best the Shuttle launch system or derivative people are starting to remind me of the folks who kept advocating larger and larger battleships…after 7 Dec 1941.

But the problem is that there is no mission AT ALL for an HLV, particularly an HLV that is enormously expensive…and which the US government cannot afford to develop or even fly. Whittington is reduced on his web site to the American patriotism argument NUTS

“It is funny how I heard people claim that only small rockets are efficient…” where?

If Musk Falcon9 did not lower the cost per pound to launch or the development cost were exorbitant…then there would be some head scratching, at least by me. But neither apparently is correct unlike a SLS HLV.

How does a vehicle which will cost a billion a launch in your viewpoint justify itself when there are far cheaper alternatives?

Robert G. Oler

Perhaps but in theory it is the spacecraft and not the rockets that are the problem. What a HLV does is reduce the number of flights needed to lift hardware. The problem is we need Spacecraft not HLV. The issuse is that there is plenty of money in the NASA budget for spacecraft, but if you blow it all on an HLV you may get nowhere.

“It is funny how I heard people claim that only small rockets are efficient…orders of magnitude more efficient than any HLV. And then SpaceX announces the F9H, which has a lower cost per payload pound to LEO than the F9. And now I am hearing all those armchair PhDs and MBAs saying that it is now OK to be up to 50mT …”

FH cost more per launch than Falcon 9. If you have a 10 ton spacecraft it would be foolish to buy a FH9 heavy(unless you get some sort of ride share thing going).

The problem I have with HLV isn’t so much the capacity it is who creates it and how is it is created. Monolithic boosters like Saturn V and most likely SLS are a bad idea. They have no other users. Space X can keep the capacity to launch the FH9 because it shares many parts with the falcon 9. They can control their costs because they don’t need a totally separate workforce like Saturn and Shuttle and the FH is not going to be a NASA only rocket.

SLS is foolish becuase congress wishes it to be capable of sending crew to the ISS. Serving the ISS does not take an HLV and should not be the role of an HLV.SLS has congress dictating to NASA what capacity the HLV should be. What if 50 tons to LEO were much cheaper to develop and Operate than 130MT? Delta for isntance can be upgraded to 50MT…demanding 70MT or 130MT may be adding a lot of cost without much benifit.

“It almost looks to me like you guys just happend to like Mr Musk, and anything he does is OK in your book. If, hypothetically, he was a lemming, I fear that one or two of you might almost be tempted to follow suit ”

I am more partial to boeing,ULA ect and with investments we could have 2 launchers capable of lifting 50MT for less than the cost of 1 launcher that lifts 130MT and it would cost NASA less per year. Oh and I still think prop depots are a smart idea that allows missions to not be limited by the size of the HLV.

Fools rush in where wise men fear to tread… but then nearly everyone working in the field thinks that its going to take another hit before anything is done. Kind of like hurricanes and tsunami’s.

Me, I’m foolish enough to think that people are not that dumb, but we’ll see.

“As I understand it, your principal concern is long-period comets dropping in from the Kuiper Belt and beyond.”

That, and SMALL DEAD COMET FRAGMENTS. The asteroids seem to be detectable, including C class, as their orbits bring them around several times before impact, but getting better coverage there would be an additional benefit

A summary of recent impacts in the Americas may be found in my book “Man and Impact in the Americas”.

By the way, Earth based detection and minimal IR is a non-trivial cost: it is estimated it will cost $1 B over the next 20 years, and we’re looking at at at least one launch/sat as a minimum requirement. Say $500 M, more likely more. That’s what JPL put in their report to the Congress, the one that Griffin and Weiler sat on

Detection is going to be a continuing problem for as long as man lives on the Earth.

” If so, what kind of active detectors do you have in mind?”

See NASA Langley’s CAPS reports. As I mentioned before, I disagree with Langley’s architecture for building them, as it strikes me that using lunar orbit would be cheaper.