Author Topic: F9H and "Dragon 2"  (Read 129375 times)

Offline Jim

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Re: F9H and "Dragon 2"
« Reply #80 on: 01/20/2011 05:09 pm »

I also think Space Solar Power

What says this is viable?

Offline tigerade

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Re: F9H and "Dragon 2"
« Reply #81 on: 01/20/2011 05:15 pm »
Are we talking about space-based solar power?

http://en.wikipedia.org/wiki/Space_solar_power

I think it's an interesting idea, but I think the challenges are way too enormous and the benefit is debatable.  I definitely don't see it on our lifetime, or the next.  But maybe the next next lifetime.  :)

Offline kevin-rf

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Re: F9H and "Dragon 2"
« Reply #82 on: 01/20/2011 05:23 pm »
Are we talking about space-based solar power?

http://en.wikipedia.org/wiki/Space_solar_power

I think it's an interesting idea, but I think the challenges are way too enormous and the benefit is debatable.  I definitely don't see it on our lifetime, or the next.  But maybe the next next lifetime.  :)

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Offline meekGee

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Re: F9H and "Dragon 2"
« Reply #83 on: 01/20/2011 05:26 pm »
uh oh - Jim and me are on the same side of the fence again.

I'd love for it to work, but I can't make the numbers fit.

Unlike other space endeavors, Space solar power has to work CHEAPLY.  Terrestrial solar, with all of its downsides (And I know these excel sheets by heart) is a formidable competitor to SBSP... 

« Last Edit: 01/20/2011 05:26 pm by meekGee »
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Offline docmordrid

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Re: F9H and "Dragon 2"
« Reply #84 on: 01/20/2011 07:58 pm »
uh oh - Jim and me are on the same side of the fence again.

Uh-Oh indeed - all three of us agree on something?

Maybe there's something to this 2012 stuff after all  :o
« Last Edit: 01/20/2011 07:59 pm by docmordrid »
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Offline Gregori

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Re: F9H and "Dragon 2"
« Reply #85 on: 01/20/2011 08:26 pm »

I also think Space Solar Power

What says this is viable?

It has lots of advantages over terrestrial solar power, being a constant source of power, and installations can be very large as there is lots of space in orbit and almost endless energy to collect. With current launch vehicles, this may not be viable, especially ULA's rockets costing 200-300 million per launch.

A combination of factors may make space based solar power viable in a few decades. The cost for producing photocells is coming down per watt.Lot of research is being done into making more efficient cells. SpaceX intends to make Falcon 9 fully reusable in the near future. There has been research into flyback stages and other kinds of reusable vehicles in the past 2 decades.

A lot of this does depends on new technology being developed that both lowers launch costs and costs of making solar cells, but I have no doubt both things will advance because of oil shortages, mitigating global warming and the start of commercial space flight market by entrepeneurs, and old companies who are trying new things.

If Space Based Solar Power becomes a reality, its going to need a lot of people in orbit to assist in constructing and maintaining this vital infrastructure.

Reusable vehicles will lower launch costs

Offline D_Dom

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Re: F9H and "Dragon 2"
« Reply #86 on: 01/20/2011 08:36 pm »
Gregori, before driving too far OT you should look at many discussions of SBSP
 http://forum.nasaspaceflight.com/index.php?topic=19831.105
« Last Edit: 01/20/2011 08:37 pm by cygnusX1 »
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Offline Gregori

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Re: F9H and "Dragon 2"
« Reply #87 on: 01/20/2011 11:12 pm »
Sorry for dragging off topic :)

Anyways, I am speculating there will be 2 new spacecraft by SpaceX after 2020. A BLEO Dragon 2 that will serve the government market and will fit on a Falcon 9 Heavy with Merlin2 engines. It will have more capabilities than Orion or the original Dragon.

The second vehicle will be a Dragon Bus, that will fit on the Falcon X and will be capable of ferrying 50+ people to private and government stations in LEO. It will be a land landing capsule with pusher escape system that can precision land at a spaceport.

I aware that there is some wishful thinking in that, but oh well!!!

Offline go4mars

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Re: F9H and "Dragon 2"
« Reply #88 on: 01/20/2011 11:50 pm »
I am speculating ...after 2020...
A BLEO Dragon 2 that will serve the government market and will fit on a Falcon 9 Heavy with Merlin2 engines. It will have more capabilities than Orion or the original Dragon.

Agreed.  But I think it will fit on a F9H with the hammerhead raptor stage (and thus be at least 6 meters in diameter).  2 versions:  "Dragon 2a" for BLEO missions (perhaps only 10 seats), and "Dragon 2b" for LEO (with 18-25 seats).  This would also fit nicely on the top of an eventual F-X (6 meter core).

I am speculating ...after 2020...
The second vehicle will be a Dragon Bus, that will fit on the Falcon X and will be capable of ferrying 50+ people to private and government stations in LEO. It will be a land landing capsule with pusher escape system that can precision land at a spaceport.
Around 2025, I also think there will be 2 versions of a dragon bus (maybe called dragon 3a and 3b).  But I instead of F-X, I think it will be launched on F-XX or something even larger.  Version 3a will be for servicing LEO and be stuffed with seats (maybe 100 or so), but 3b will only share a few basic elements with 3a because it is meant to land on Mars and stay there.  3b might not look a lot like 3a, will have a lot less seats in it, and could even include things like giant ballutes.  A few might be landed per colony mission to Mars (for landing various mission components/equipment/modules).  If SpaceX has a methane/oxygen version of Merlin 2, then I wouldn't be shocked to see these sent back from Mars to LEO via ISRU rocket fuel to get re-stocked with more Mars-bound goods and people.     

I aware that there is some wishful thinking in that, but oh well!!!

If there weren't wishful thinkers, we would still be cavemen. 

100 people per flight !?!  Well, if F-XX shoots 15 times more mass to LEO than F9, then just maybe 100 people isn't completely crazy.  Just close your eyes for a moment and imagine that the stages are reusable...   
And remember that methane is cheaper than RP-1.  Imagine that the development costs were mostly paid for by government grants (contracts) and by bootstraps through a philanthropic company (profitless).  Unburdened by development costs, how much would a 1-way ticket to Mars cost in this scenario?      mmm...   I can almost feel myself slam dunking a basketball into a 16 foot high hoop already. 

Sweet dreams everybody!
« Last Edit: 01/21/2011 12:05 am by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Jim

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Re: F9H and "Dragon 2"
« Reply #89 on: 01/21/2011 12:34 am »
Get real.

There will winged RLVs for passengers and none of these inane large capsules.  There isnt going to be a replacement govt station for the ISS nor a Dragon 2

Offline docmordrid

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Re: F9H and "Dragon 2"
« Reply #90 on: 01/21/2011 01:32 am »
Sounds like you're a believer in SABRE, or something like it?
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Offline go4mars

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Re: F9H and "Dragon 2"
« Reply #91 on: 01/21/2011 04:18 am »
Get real.

There will winged RLVs for passengers and none of these inane large capsules.  There isnt going to be a replacement govt station for the ISS nor a Dragon 2

LOL!!   Now that's some cold water to the face!

There will winged RLVs for passengers and none of these inane large capsules.

SSTO?  or stages?

Why winged?  Seems to me that a generous helping of PICA should do the trick for a 6 or even 10 meter capsule.    No?

There isnt going to be a replacement govt station for the ISS

Agreed.  Private sector's turn. 

nor a Dragon 2
In the sense of a propulsive landing/upgraded dragon?  Or in the sense of a bigger future version?





« Last Edit: 01/21/2011 04:19 am by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Gregori

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Re: F9H and "Dragon 2"
« Reply #92 on: 01/21/2011 11:26 pm »
Get real.

There will winged RLVs for passengers and none of these inane large capsules.  There isnt going to be a replacement govt station for the ISS nor a Dragon 2

People have been waiting for these magical winged RLV's since the 1970's....and look where that got us.  ;)

I know capsules are not very aesthetically pleasing, but they are simpler, safer and cheaper than space-planes and are an easier extension of what SpaceX and Boeing are doing. If RLV's show up, capsules can take advantage of them, but they're not dependent on them.


There very well may be a replacement or extension for the ISS if NASA doesn't go BLEO after 2020. With the HLV design NASA sent to congress, it doesn't look like NASA is going any further than LEO for a long time.


Offline Lars_J

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Re: F9H and "Dragon 2"
« Reply #93 on: 01/21/2011 11:38 pm »
Capsules are great. Economical and safe.

BUT... They will never open up mass transportation (of people) to space. Some kind of reusable passenger spaceplane (or VTVL) will have to be developed for that. And we are not there yet.

Expecting SpaceX to create a "Dragon 2" with a 10-20 passenger capacity is just silly IMO.

The closest technological path to a true reusable passenger craft is probably a two-stage spaceplane. (The first stage being a flyback booster or jet+rocket-propelled carrier aircraft)
« Last Edit: 01/21/2011 11:41 pm by Lars_J »

Offline docmordrid

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Re: F9H and "Dragon 2"
« Reply #94 on: 01/22/2011 12:43 am »
Skylon/SABRE, or something much like it.
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Offline meekGee

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Re: F9H and "Dragon 2"
« Reply #95 on: 01/22/2011 01:23 am »
aesthetics aside, and agreeing that vehicle reusability, benign landing, and quick turn-around are all key, I don't see the argument from this to wings.

The mass of the wings goes with the mass of the vehicle, and so does the propellant necessary for a powered landing.  If you reduce the terminal velocity to near 150 m/s and assume exhaust velocity of 2500 m/s, the propellant mass will be 6-7% of the vehicle mass.  Can wings ever beat that?  Can they even come close?

Propulsive landing requires the rocket engines mass too, and maybe an emergency chute too, but wings also require more heat shield mass, and present issues during ascent.  And a vertical lander can land in a lot more places than a winged vehicle.

I am not sure how wings can win the game.  I think the desire for them is more an artifact of watching too much sci-fi.

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Offline Seer

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Re: F9H and "Dragon 2"
« Reply #96 on: 01/22/2011 03:40 am »
aesthetics aside, and agreeing that vehicle reusability, benign landing, and quick turn-around are all key, I don't see the argument from this to wings.

The mass of the wings goes with the mass of the vehicle, and so does the propellant necessary for a powered landing.  If you reduce the terminal velocity to near 150 m/s and assume exhaust velocity of 2500 m/s, the propellant mass will be 6-7% of the vehicle mass.  Can wings ever beat that?  Can they even come close?


I think that some of your figures are off.  Terminal delta v is only one part of the requirement, though its only about 50-100 m/s. Correcting range dispersion is another 100-200 m/s. Gravity losses while braking and hovering are another 100 m/s at least. So that's 250-400 m/s for at most 350s isp if you assume hydrogenlox (for an rlv stage), and 250s for hypergolics.
Plus you have the mass of the landing propellents tank. Since a wing and tail are about 10%, its basically a wash mass wise.




Offline meekGee

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Re: F9H and "Dragon 2"
« Reply #97 on: 01/22/2011 03:53 am »
I think the range correction  is too high, I agree on the gravity drag.  The Landing/LAS match-up nulls out most of the weight of the tanks, especially if you assume an emergency chute landing in case of an abort.

Wings + tail + extra heat shield for those + extra structure to support two main load directions + rolling landing gear - all for only 10%?   That doesn't sound right.   Sounds maybe right for a regular airplane.

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Offline Seer

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Re: F9H and "Dragon 2"
« Reply #98 on: 01/22/2011 06:14 am »
I think the range correction  is too high, I agree on the gravity drag.  The Landing/LAS match-up nulls out most of the weight of the tanks, especially if you assume an emergency chute landing in case of an abort.

Wings + tail + extra heat shield for those + extra structure to support two main load directions + rolling landing gear - all for only 10%?   That doesn't sound right.   Sounds maybe right for a regular airplane.



The wing and tail are 10%. The rest is extra. But the capsule will have abort motors/landing engines,  heavy ablative heatshield and landing legs.

Offline go4mars

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Re: F9H and "Dragon 2"
« Reply #99 on: 01/22/2011 01:20 pm »
The closest technological path to a true reusable passenger craft is probably a two-stage spaceplane. (The first stage being a flyback booster or jet+rocket-propelled carrier aircraft)

I agree that a 2 (and wouldn't rule out 3) stage spacecraft is necessary.  And I agree that stages would ideally be flyback.  But I don't understand the need for wings.

Capsules are great. Economical and safe.

BUT... They will never open up mass transportation (of people) to space. Some kind of reusable passenger spaceplane (or VTVL) will have to be developed for that. And we are not there yet.

Why?  Capsules have more efficient mass fractions (assuming the continued need for abort functionality for the forseeable future).  They don't need giant runways.  Please explain your dismissal of capsules in exchange for a new version of "shuttle orbiter". 

http://www.astronautix.com/craft/bigemini.htm 

"requiring a resupply craft that could deliver up to 12 passengers and 12 metric tons of payload 6 to 14 times a year, returning up to 7 cubic meters of cargo each time. Big G could provide such a capability by 1971, using Gemini technology applied to Gemini and Apollo hardware, with minimum interference to the higher priority Apollo lunar landing program."

Back in NASA's Apollo era, they thought a handy little 12-seater capsule would be great for supporting NASA and commercial stations that were projected to be up and running in the 1970's.
« Last Edit: 04/04/2012 04:05 pm by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

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