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Falcon Surprise, SpaceX Says Something Big is Coming
ElkGroveDan
post Apr 6 2011, 10:04 PM
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QUOTE (ugordan @ Apr 6 2011, 11:09 AM) *
Tanks stretched by that much would look unnaturally skinny for F9's diameter.

I'm sure those sections will be encouraged to wear horizontal stripes.


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ugordan
post Apr 6 2011, 10:09 PM
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QUOTE (stevesliva @ Apr 6 2011, 11:37 PM) *
Is that where the figure comes from?

No, that would only partially account for it. The press release stated that propellant crossfeed could be turned off for payloads less than about 45 tons suggesting the crossfeed accounts for "only" a 8 ton boost. There's really no way of approaching that 45 ton figure without stretched tanks first, even with tanks having one of the best propellant mass fractions in the world.

Falcon 9 is supposed to be able to boost 10 tons. 3 identical cores can obviously only make that 30-ish tons.
Parallel with this Falcon Heavy announcement, there was a brief mention of an upgraded Falcon 9 as well, also 14 meters taller, weighing 480 tons and being able to lift 16 tons. 3*16 is close to the above figure of 45 tons without crossfeed. So that about checks out. The vastly higher thrust on Merlin 1d is basically unused with the current tanks, in fact the engines might actually have to be derated in order for "non-upgraded" Falcon 9's not to jump off the pad and use up all the propellant too soon.

Previously the engine upgrade was targeted at 125 klbf, they could actually reduce the number of these new 140 klbf engines on Falcon 9 down to 8 and have the same performance as before.


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algorimancer
post Apr 7 2011, 03:31 PM
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Launch costs of <$1000/lb. encourage the notion of an UMSF craft. I would think that we could come up with enough donations to launch a 100-500 lb spacecraft, building on the notion of the CubeSat program. Given a piggyback beyond LEO, adding an ion drive and perhaps a magsail (https://secure.wikimedia.org/wikipedia/en/wiki/Magnetic_sail), an asteroid (perhaps 16 Psyche or 15 Eunomia?) flyby or even rendevous/landing might be entirely feasible, given a bit of creativity. I would envision 5 years to launch, followed by a 5 year mission.
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djellison
post Apr 7 2011, 03:48 PM
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QUOTE (algorimancer @ Apr 7 2011, 08:31 AM) *
Launch costs of <$1000/lb. encourage the notion of an UMSF craft. I would think that we could come up with enough donations to launch a 100-500 lb spacecraft, building on the notion of the CubeSat program.


The most expensive part has never been the launch. Build a spacecraft, testing it, the ground systems required to use it - that's the expensive part with spacecraft, typically.
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Syrinx
post Apr 7 2011, 06:28 PM
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You know the old saying. In for $1000, in for a pound. Heh.

I would like to entertain the idea of a "UMSF" craft. I'd be in for a few pounds. Integration, testing, comms, all that business is definitely a concern.
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algorimancer
post Apr 11 2011, 12:45 PM
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QUOTE (Syrinx @ Apr 7 2011, 01:28 PM) *
...
I would like to entertain the idea of a "UMSF" craft. I'd be in for a few pounds.


I too would easily be in for a few pounds, especially over a 5+ year time frame.

It has been my experience that much of the expense of this sort of endeavor is personnel. In the case of an UMSF craft, I would expect that most of this would be volunteered time. Also, I note that rather a lot of the relevant professionals are members of this site. It would certainly be of interest to work-up a reference design and costs. Are ion drives prohibitively expensive? Would we need to buy time on the DSN, or could comms be more improvised (pulsed laser, for instance)? This could be an opportunity to test some new technology. Then there's also the possibility of commercial sponsors.
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djellison
post Apr 11 2011, 01:56 PM
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I repeat - you are catastrophically underestimating the costs, complexity and challenges involved.

The very very smallest and simplest spacecraft you can possibly put together is a 1U cubesat - which is a $50-100,000 investment. Moreover, getting it off the ground is about the same. And that has no payload, no ground stations, no actual 'use'.

A literal build-to-print 3U cubesat is $250k. ( google 'Cubesat Kit' for an actual price list ) Plus - the international nature of UMSF renders ITAR a significant hurdle that would almost certainly bring things to a halt if money were no object.

DSN time? It's tens of thousands of dollars..PER HOUR. An Ion engine? Hundreds of thousands, if not millions. Pulsed laser communications? You're now talking about a large and powerfull 3-axis stabilised spacecraft with significant power ( 10's of millions ) and multiple large apature ground stations ( 10's of millions )

If you want to have some sort of involvement in an actual spacecraft or spacecraft analogous project.... then these are actual options

Contribute to the Planetary Society Lightsail project ( https://planetary.org/join/donate/K09ls1w )
Find a local university that's conducting a CubeSat project, and offer your talents, time and expertise.
Get involved in a high-altitude balloon flight. I don't thing there's a country in the western world where some radio-hams or soldering-iron wielding tech heads are not building them and launching them monthly.
Heck - my latest solo project is a small R/C plane with an autopilot and I'm having great fun.

We're not building a spacecraft here. I'm serious.

Syrinx, algorimancer.... I'm telling you as a UMSF regular...and now as an Admin.... you're talking fiction, stop it.
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algorimancer
post Apr 11 2011, 05:11 PM
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As I see it, you're prematurely squelching a (relevant) discussion before it can even get underway. But you're the administrator, so I'll drop it.
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djellison
post Apr 11 2011, 08:27 PM
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QUOTE (algorimancer @ Apr 11 2011, 10:11 AM) *
, you're prematurely squelching a (relevant) discussion


I'm squelching a discussion on this forum between two guys who are dangerously and embarrassingly uninformed regarding the costs and complexities of building a spacecraft. Furthermore - it has near zero relevance to this thread. What I HAVE done is give you suggestions of how you might participate or contribute to space or space analogous projects.

There is nothing stopping you opening up a forum, yahoo group, whatever... to continue that discussion. Indeed, I would encourage you to do so.

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Greg Hullender
post Apr 13 2011, 01:38 AM
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Something I've always liked about UMSF is that it doesn't allow discussions that are too detached from reality. I had wondered if that would continue under new management. Glad to see it.

--Greg
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