Author Topic: General Falcon and Dragon discussion (Thread 11)  (Read 398757 times)

Offline whitelancer64

Re: General Falcon and Dragon discussion (Thread 11)
« Reply #500 on: 12/24/2014 02:31 pm »
Does anybody know the plans for partial evacuations, as in a medical emergency?

medical emergencies on the ISS are essentially handled on a case-by-case basis. both NASA and Roscosmos have a flight surgeon and a medical staff ready to advise and instruct should medical treatment be required for anyone on the ISS. the most normal spaceflight medical complications are well known and fairly well understood, although this is a subject of much of the ongoing research on the ISS. the more concerning medical situations on the ISS have included cuts, burns, various infections, and heart conditions. there is a great deal of literature on space medicine available, searching around you can find a lot of reading material.

the current procedure seems to be that should a medical evacuation be necessary, a Soyuz capsule would be used. the particulars would depend on the severity of the medical emergency, but most likely this would be done only in a critical situation, so you'd have a Soyuz pilot, the patient, and a crew member dedicated to tending to the patient descending back to Earth, where i'm sure there would be a large contingent of medical personnel assembled to treat them.
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Offline Vultur

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #501 on: 12/28/2014 07:33 pm »
What would the delta-v of a Falcon 9v1.1 first stage with no second stage and no/very small payload be? How close could it get to SSTO? What if you took the landing legs off?

Offline S.Paulissen

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #502 on: 12/28/2014 07:47 pm »
What would the delta-v of a Falcon 9v1.1 first stage with no second stage and no/very small payload be? How close could it get to SSTO? What if you took the landing legs off?

The first stage alone ballparks to around 8500 m/s delta-V ignoring gravity losses and aero-drag.  LEO required delta-V is estimated to be 9-10 km/s depending on the rocket's given losses.  The stage would need to muster an average ISP closer to 310 to come close to achieving SSTO with no payload.  This orbit would be exactly KSC 28.5degrees and nowhere near the orbital plane and altitude of the ISS. 

I feel this is a very optimistic estimate.
« Last Edit: 12/28/2014 08:41 pm by Exclavion »
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Offline Vultur

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #503 on: 12/29/2014 01:56 am »
What would the delta-v of a Falcon 9v1.1 first stage with no second stage and no/very small payload be? How close could it get to SSTO? What if you took the landing legs off?

The first stage alone ballparks to around 8500 m/s delta-V ignoring gravity losses and aero-drag.  LEO required delta-V is estimated to be 9-10 km/s depending on the rocket's given losses.  The stage would need to muster an average ISP closer to 310 to come close to achieving SSTO with no payload.  This orbit would be exactly KSC 28.5degrees and nowhere near the orbital plane and altitude of the ISS. 

I feel this is a very optimistic estimate.

Wow. That is really surprisingly close. Given that the F9 first stage is designed to carry a 2nd stage (and thus could have quite a bit more fuel and still have a TWR > 1 at launch) could a SSTO be made with Merlin 1D technology?

Offline guckyfan

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #504 on: 12/29/2014 06:54 am »
Wow. That is really surprisingly close. Given that the F9 first stage is designed to carry a 2nd stage (and thus could have quite a bit more fuel and still have a TWR > 1 at launch) could a SSTO be made with Merlin 1D technology?

I am continually amazed by the fascination something as completely useless as a SSTO rocket seems to have!

I say explicitly rocket. Other designs like Skylon not included.

Offline cambrianera

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #505 on: 12/29/2014 09:08 am »
Wow. That is really surprisingly close. Given that the F9 first stage is designed to carry a 2nd stage (and thus could have quite a bit more fuel and still have a TWR > 1 at launch) could a SSTO be made with Merlin 1D technology?

I am continually amazed by the fascination something as completely useless as a SSTO rocket seems to have!

I say explicitly rocket. Other designs like Skylon not included.

World is full of useless but fascinating things.
And full of of things useless today, but useful tomorrow (and viceversa).
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Offline fast

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #506 on: 12/29/2014 09:47 am »
What would the delta-v of a Falcon 9v1.1 first stage with no second stage and no/very small payload be? How close could it get to SSTO? What if you took the landing legs off?

The first stage alone ballparks to around 8500 m/s delta-V ignoring gravity losses and aero-drag.  LEO required delta-V is estimated to be 9-10 km/s depending on the rocket's given losses.  The stage would need to muster an average ISP closer to 310 to come close to achieving SSTO with no payload.  This orbit would be exactly KSC 28.5degrees and nowhere near the orbital plane and altitude of the ISS. 

I feel this is a very optimistic estimate.

Wow. That is really surprisingly close. Given that the F9 first stage is designed to carry a 2nd stage (and thus could have quite a bit more fuel and still have a TWR > 1 at launch) could a SSTO be made with Merlin 1D technology?

possibly it can be made even right now, if you will launch you stretched F9R first stage from mountain takeoff field at altitude above 5000-6000m. Increased Isp will, low drag will greatly benefit...

it was discussed in other tread

Offline S.Paulissen

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #507 on: 12/29/2014 04:44 pm »
Wow. That is really surprisingly close. Given that the F9 first stage is designed to carry a 2nd stage (and thus could have quite a bit more fuel and still have a TWR > 1 at launch) could a SSTO be made with Merlin 1D technology?

Not really; a lot of first stages are very similar on two stage rockets.  It's not economical to launch something that barely makes LEO with a tiny payload fraction when, for marginal more cost, staging will increase payload many fold times.    It's useless for high energy orbits. 

Furthermore, pertinent only to SpaceX, this SSTO vehicle has nearly no possibility of recovery coupled with low margins and capability.

So you know, with a 10m tank stretch and existing 1d performance, they could SSTO a payload between 1000-2000kg.  Again, at KSC minimum energy LEO.  With the purported 112% thrust 1d, you could loft a 13m stretch with a payload of ~3000kg.  Compare this with the nearly 15000kg the existing two stage rocket can put into the same orbit.


I am continually amazed by the fascination something as completely useless as a SSTO rocket seems to have!

I say explicitly rocket. Other designs like Skylon not included.

I generally agree. Payload fraction is awful even if the first stage could do SSTO, which it could with a modest stretch. 

Skylon is vaporware until I see a full scale, flight weight, SABRE engine work as well as projected at speed/altitude conditions as well as a rocket.  Until that point, it's a bunch of useless/fascinating hardware.
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Offline dror

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #508 on: 12/29/2014 05:37 pm »
What would the delta-v of a Falcon 9v1.1 first stage with no second stage and no/very small payload be? How close could it get to SSTO? What if you took the landing legs off?

The first stage alone ballparks to around 8500 m/s delta-V ignoring gravity losses and aero-drag.  LEO required delta-V is estimated to be 9-10 km/s depending on the rocket's given losses.  The stage would need to muster an average ISP closer to 310 to come close to achieving SSTO with no payload.  This orbit would be exactly KSC 28.5degrees and nowhere near the orbital plane and altitude of the ISS. 

I feel this is a very optimistic estimate.
Can subcooled densified rp1 change that?
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Offline S.Paulissen

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #509 on: 12/29/2014 07:54 pm »
Can subcooled densified rp1 change that?

No.  You get somewhere in the vicinity of 3.3% more fuel at -20°C assuming the whole propellant load is RP-1 (which it's not, it's about 1/4 of it with 3:1 O:F mix) which allows ~25m/s more deltaV.
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Offline Norm Hartnett

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #510 on: 12/29/2014 11:56 pm »
I haven't seen this mentioned around here but Mike Killian caught a remarkable photo of the last ISS resupply launch. See it about half way down the page of this somewhat older article in America Space.

http://www.americaspace.com/?p=73981

It shows the first and second stage burns and also the first stage reentry/landing burn. Very cool!
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Offline Robotbeat

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #511 on: 12/30/2014 01:20 am »
Can subcooled densified rp1 change that?

No.  You get somewhere in the vicinity of 3.3% more fuel at -20°C assuming the whole propellant load is RP-1 (which it's not, it's about 1/4 of it with 3:1 O:F mix) which allows ~25m/s more deltaV.
Falcon Heavy boosters can do it easily without needing propellant densification. They have even better mass fraction than a F9 core, since the tanks are stretched.  Mass fraction of 30, and 3 of the engines are restartable (the center one several times), so you can also use the much more efficient multi-burn trajectories. And you'd have pretty good T/W ratio (especially considering recent improvements in Merlin 1D), so low gravity losses. Aero losses would also be very low due to the aspect ratio of such a tall and skinny rocket.

...but it'd be expendable and thus pointless compared to a Falcon 9 reusable which could get better performance with less cost. F9R should be able to do 13 tons partly reusable (according to SpaceX), especially with down-range barge landing. The SSTO expendable FH booster would get about 5 tons or so to low LEO.
« Last Edit: 12/30/2014 01:26 am by Robotbeat »
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Offline Zed_Noir

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #512 on: 01/01/2015 05:43 am »
The folks at Hawthorne release a year in review video for 2014


Offline mme

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #513 on: 01/01/2015 08:54 pm »
The folks at Hawthorne release a year in review video for 2014
...
I know that some people are put off by "PR," but I have to admit that I love this.  It really conveys the excitement of spaceflight to me.  Looking forward to the landing attempts, the abort tests, all the launches and of course the possibility of FH.  2015 is going to be an interesting year!
Space is not Highlander.  There can, and will, be more than one.

Offline Lar

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #514 on: 01/02/2015 01:41 am »
I think some of the footage of the water landing may not have been released before, or maybe I missed it. Nice vid.
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Offline MattMason

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #515 on: 01/02/2015 02:25 am »
I think some of the footage of the water landing may not have been released before, or maybe I missed it. Nice vid.

They greatly stabilized the plane-chaser water landing by slowing it down and probably enhancing the sharpness. It seemed far more detailed.
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Offline sghill

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #516 on: 01/06/2015 10:32 am »
There were some great shots of operational F9 grid fins in this morning's launch attempt coverage. :)

Bring the thunder!

Offline fthomassy

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #517 on: 01/09/2015 05:54 pm »
Have not seen this on the forum's yet and thought it would entertain (not likely to inform many on NSF).

https://twitter.com/SpaceX/status/552876085743218688
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Offline The Amazing Catstronaut

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #518 on: 01/09/2015 06:21 pm »
Have not seen this on the forum's yet and thought it would entertain (not likely to inform many on NSF).

https://twitter.com/SpaceX/status/552876085743218688

Yup, it's already been posted up. Thank you for the reminder however.

It's great that SpaceX tweets stuff like this; it's excellent public outreach for the Falcon.
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Offline dglow

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Re: General Falcon and Dragon discussion (Thread 11)
« Reply #519 on: 01/12/2015 03:17 am »
Have not seen this on the forum's yet and thought it would entertain (not likely to inform many on NSF).

https://twitter.com/SpaceX/status/552876085743218688

Hadn't seen that, thanks! The 'Bird 9' is a riff upon the 'Up-Goer Five', here: https://xkcd.com/1133/

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