SpaceX is a go for April 30th: 1st commercial launch to space station

[sojourner]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Sojourner, are you on the nasaspaceflight.com forums? I post there quite a bit. (as Lars_J) I've expressed a lot of skepticism towards the speculation from that single image.

You know, the one thing that annoys me over there is the elitism of the posters. It seems that people go unresponded to if they are new to the site or haven't demonstrated their credentials. For example, I posted a perfectly reasonable question about the F9R first stage's center of gravity here and got no response at all.

 

[Hyperspace05]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Sojourner, are you on the nasaspaceflight.com forums? I post there quite a bit. (as Lars_J) I've expressed a lot of skepticism towards the speculation from that single image.

You know, the one thing that annoys me over there is the elitism of the posters. It seems that people go unresponded to if they are new to the site or haven't demonstrated their credentials. For example, I posted a perfectly reasonable question about the F9R first stage's center of gravity here and got no response at all.

While there is some elitism going there, I think that may just more of a case where people just don't know the answer.

I considered responding, but since I know jack, I would just be spouting BS. (hmm, which may not be much different from my normal posts)

 

[Hyperspace05]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

New pictures released:


My new desktop background

Also, a new picture of the recovery:

 

[Psion]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Sojourner, are you on the nasaspaceflight.com forums? I post there quite a bit. (as Lars_J) I've expressed a lot of skepticism towards the speculation from that single image.

You know, the one thing that annoys me over there is the elitism of the posters. It seems that people go unresponded to if they are new to the site or haven't demonstrated their credentials. For example, I posted a perfectly reasonable question about the F9R first stage's center of gravity here and got no response at all.

While there is some elitism going there, I think that may just more of a case where people just don't know the answer.

I considered responding, but since I know jack, I would just be spouting BS. (hmm, which may not be much different from my normal posts)

Consider creating a second account to answer your ignored questions with obviously wrong bullshit. This will prompt outraged corrections from the elitists and you'll get the answers you need. I do that around here and it works all the time.


...


Uh ... whoops.

 

[Hyperspace05]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

LOL!

 

[Crazy Eddie]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Those have to happen if Musk has any intention of fulfilling some of the things he has said so far. He is repeating over and over that one of his goals is Mars, and while Falcon Heavy can carry Martian payloads, it doesn't quite cut it. This and the other things that he have been mumbling are strongly suggesting that he intends to work on those (or similar ones) once he gets the opportunity.

That doesn't suggest they have any need for a heavy lift vehicle. Quite the opposite in fact, Musk probably envisions a spaceflight architecture based around the reusable Falcon 9H and dragon-derived orbiters. There isn't a whole lot you could do with a single HLV that couldn't be more efficiently accomplished with three MLVs, especially if the smaller rockets are reusable.

Once the reusable F9 is operational, the FH will be using the same reusable 1st stage as boosters. Their reusable work applies to future variants of both the F9 and FH.

I'm confused... are you saying the Falcon Heavy DOES qualify as an HLV?

 

[Crazy Eddie]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Wouldn't heavier launchers be cheaper in terms of fuel though? FH can lift five times what F9 can, and uses, what, three times more fuel? If you:
1. Developed full reusability all the way to Mars.
2. Increased the size of the rocket/engines.

True as that is, the cost of the fuel is a VERY small expense for the overall launch budget. Off the top of my head, the larger and more sophisticated engines alone would easily offset any cost savings in fuel efficiency, to say nothing of the added cost of the rocket itself, extra man hours needed to get it flight ready, and the fixed cost of the larger and more complicated launch facilities needed to maintain it.

 

[Hyperspace05]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

I'm confused... are you saying the Falcon Heavy DOES qualify as an HLV?

It depends on how you define a HLV. (100mt capability? 70 mt? 50mt?) But it is a heavy version of the falcon 9.

 

[publiusr]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

I'd call 100 tons an HLLV. But F9 heavy comes in at what--40-53 tons is what i've heard. The reason I support a true HLLV isn't just mass but payload shrouds. A hydrolox core allows wide payload shrouds. F9 heavy is based on a denser kerolox platform. Also Josh Hopkins expressed certain "Doubts upon Depots" in an article for The Space Review, and an Aviation Week and Space Technology blurb I linked to over at www.bautforum.com months back cited a need for 36 Delta IV heavies--(or 24 F9s) for a depot. Moreover, it was shown that boil-off was a major stumbling block for now. An HLV allows less complex BEO missions in that all the fuel goes up at once, and is staged off as thrust--traded for inertia that cannot leak.

The current trend is for comsats to lose any on board liquid propellant for electric drives due to the problems many sat providers have had with thrusters going out and being forced to limp to orbit using electric systems--which will be a boon for Musk BTW:
http://www.spacenews.com/satellite_telecom/120511-europeans-check-boeing-electric-sats.html

It's just best not to have a lot of plumbing and liquids sloshing around up there--with a lot of Rube Goldberg docking. An HLV allows for more direct missions with as few rendevous as needed. The Falcon XX is a possibility.

 

[sojourner]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Yeah, it's a shame we don't have experience docking/building things in orbit... oh wait, ISS. It's also a shame we don't have experience transferring fuel on orbit... Oh wait, ISS.

Fuel depots are not a difficult concept and the benefits far outweigh the deficits.

HLV's are just not cost effective at one every 2 years. I'd rather have a medium launcher with a much higher (and successful) flight rate.

 

[Hyperspace05]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

There are certain stumbling blocks to solve for cryogenic propellant depots, but it is unquestionable that it is going to happen real soon. We won't be able to afford going anywhere without it - even with "HLLV's".

Anyone expressing "doubts about depots" is heavily invested in creating huge launch vehicles we cannot afford to operate. I would express huge doubts about their objectivity. It's like arguing back in 1900 that gas stations were a bad idea - and they we should do all transportation with huge trucks that had to fill up at the refinery.

We don't need 100 mt launchers. Not even 70 mt. The solar system is open to us, with with even smaller launchers, such as FH. Even the Delta IV-Heavy (at 25 mt) could be used for lunar flights if we wanted to - only 3 launches per mission. And with the FH @ 50 mt, one launch is enough to send a spacecraft with crew or to resupply a Lagrange or lunar orbit station.

And until we have cryogenic depots, we can still do hypergolic depots. (which will certainly be needed for a reusable lunar lander) As sojourner states, we already have a hypergolic depot in orbit - ISS. We can build far better ones if we just fund it.

 

[Cutter John]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

I'm a bit of a noob to all this so forgive the question. But what happens to the Dragon capsule now? Is it meant to be reused for another flight? Personally I'd love to see it end up in the Smithsonian at some point. It really is a piece of history.

 

[sojourner]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Dragon capsule's are designed to be re-used, but this one is going on a road tour and will end up on display somewhere.

 

[YellowSubmarine]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

During one of the briefings it was mentioned that new Dragons will be constructed for all resupply missions, but some of them might be reused for other SpaceX uses, including DragonLab.

 

[SilentP]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Sorry, but what is a hypergolic depot? And what would the purpose of a cyrogenic depot be in terms of storage?

 

[sojourner]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Both of those refer to the type of fuel being stored. Hypergolic would be fuels like kerosene and other hydrocarbons while cryogenic would be primarily referring to liquid hydrogen.

 

[publiusr]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Kerosene isn't a hypergolic--thats fuels like UDMH, MMH, "Aerozine," pentaborane, zip propellants. Anything that will combust upon touching an oxidant--like nitrogen tetroxide--that too is a hypergolic.

Now kerosene and HTP (pure H2O2 that blew the nose off the Kursk from a torpedo) are non cryogenic and storable at room temps like hypergolics are, but you still need the spark plug, if you will.

So while they are storable propellants, they are not hypergolic. Also there is a movement away from hypergolics due to toxicity.

Some of you might remember the recent satellite shoot-down where folks were worried about the threat of that one small craft's hypergolic fuel. Now, maybe that was just a fancy excuse for a test of the Standard Missile 3, and maybe it wasn't. At any rate, hypergolic depots are simply not on the table.

Anyone expressing "doubts about depots" is heavily invested in creating huge launch vehicles we cannot afford to operate. I would express huge doubts about their objectivity.

Actually it was the individual work worked for ULA and did work on the DTAL lander concept:
http://www.ulalaunch.com/site/docs/...rationsIncorporatingAccessibility20067284.pdf
http://www.thespacereview.com/article/1447/1

An approach using propellant transfer appears to be more expensive than building some variety of heavy lift vehicle


In fact, it doesn't need to be either or
http://www.aviationweek.com/Article.aspx?id=/article-xml/asd_11_03_2011_p01-02-389517.xml
http://www.spacesafetymagazine.com/2011/11/06/nasa-strongly-in-orbit-fuel-depots/

"Michael Gazarik, NASA’s space technology program director, says that CPST and the Space Launch System (SLS) heavy-lift rocket currently under development are complementary technologies. 'To explore deep space we need a heavy-lift vehicle — SLS — and we need this technology.'"

Still, the position of folks in the know is that depots are what we cannot afford now, in that "concerns about fuel boil-off in orbit remain. A paper presented by Patrick R. Chai and Alan W. Wilhite of the Georgia Institute of Technology at this year’s International Astronautical Congress estimates that depot tanks would lose about $12 million worth of propellant a month in low Earth orbit if protected only with passive insulation. But the state of the art in cryocoolers that would be needed to prevent boil-off falls short by 'an order of magnitude' and would require “significant research” to meet likely requirements."

More:
http://www.bautforum.com/showthread...n-is-doing-it-again-...?p=1957541#post1957541
http://spacenews.com/commentaries/111031-propellant-depots-instead-heavy-lift.html

The challenge for fuel depots is simply that the marginal specific cost of payload to orbit is generally lower for larger launch vehicles.

Lots of rancor remain:
http://news.yahoo.com/space-based-fuel-depot-debate-heats-again-214200266.html
http://www.bautforum.com/showthread.php/127444-Change-of-Focus-of-NASA

The SLS and the Multi-Purpose Crew Vehicle (MPCV) are needed today. Fuel depots will be needed tomorrow, when a robust space operations infrastructure has been established and operations beyond LEO are common.

So, spaceflight is harder than popular culture has led on.
http://www.thespacereview.com/article/2069/1

 

[sojourner]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Kerosene isn't a hypergolic--thats fuels like UDMH, MMH, "Aerozine," pentaborane, zip propellants. Anything that will combust upon touching an oxidant--like nitrogen tetroxide--that too is a hypergolic.

You're right, my mistake.

 

[Crazy Eddie]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

I'm personally of the opinion that the entire concept of an orbiting fuel depot is doomed to remain a power-point proposal until somebody develops a practical/non-toxic monopropellant for orbiting spacecraft. That will probably require some sort of propulsion system paradigm shift; either widespread adoption of NOFBX, or ion thrusters that can efficiently use more easily storable propellants.

Obligatory nod to Arthur C. Clarke; in Odyssey Three the most advanced ships in the solar system were all using water as a reactant mass for what was basically a nuclear-thermal rocket.

 

[sojourner]

Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

Yeah it just goes back to the problem that chemical engines aren't a good choice after you reach orbit.