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#26 2017-12-06 10:45:14

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,500

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

SpaceNut-
I believe all 3 of the soon-to-be-flown Falcon Heavy cores are already at the Cape, and will be test fired there. I don't know if they will do a test fire of all 3 stages at once, though. I believe the plan was to fire them individually? I may be wrong about this, and hoping anyone else with better information will correct me.

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#27 2017-12-06 11:42:52

RobS
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From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
Website

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

They were test fired individually in Texas because there is no stand where all three can be fired together. The plan is to set them up on the launch pad and test fire them together later this month.

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#28 2017-12-06 15:24:32

louis
Member
From: UK
Registered: 2008-03-24
Posts: 3,818

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

Interesting video on Falcon Heavy launch.

https://www.youtube.com/watch?v=fN65OmwXqAo


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#29 2018-01-06 19:05:34

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 12,701

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

Feasibility of composite fuel tanks for BFR 2.4 and 5.5 meter tanks eventually filled with liquid hydrogen and pressure cycled 20 times with a 40 to 30% mass saving over alminum but as stated these are not actual size and means lots of engineering.

The BFR is to measure a staggering 30 feet by 348 feet, consisting of a first stage booster and second stage ship 157 feet long. Musk hopes to launch the first 35-story BFR toward the red planet by 2022.

The booster is lifted by 31 Raptor engines to produce produce liftoff thrust of 5400 tons, which will lift the total vehicle mass of 4400 tons.

Make first stage around 3,150 to 3,215 and since reuseable is most likely the 85 ton payload. The mass fraction of 11% would mean fuel is 2,803.5 . This makes oxygen 2462 and methane 688.

The 2nd stage cargo area is where the passengers are kept, at a pressurized volume of 825 cubic meters.
It will have a dry mass of 85 tons, plus a propellant mass of 1,100 tons.
The fuel tanks hold 240 tons of methane, while the oxygen tank holds 860 tons of liquid oxygen.
http://exrocketman.blogspot.com/2017/10 … ge-of.html

The whole design is capable of carrying a payload of up to 150 tons or 250 in expendable mode, but the typical return payload will come to around 50 tons.

http://space.skyrocket.de/doc_lau/bfr.htm

bfr__1.jpg

A refueled ITS will be able to bring back quite a bit. A trip departing Mars could reach Earth with one tank of fuel too, as long as the payload stays under 20-50 tons.

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#30 2018-01-07 09:31:01

louis
Member
From: UK
Registered: 2008-03-24
Posts: 3,818

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

Space X have already conducted pressure tests on their full scale model I believe:


http://uk.businessinsider.com/spacex-ca … st-2016-11


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#31 2018-01-07 10:24:59

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 12,701

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

spacex-carbon-fiber-fuel-tank-ocean-barge-test.jpg

Musk also told redditors that his engineers would haul the prototype out to sea and "take it up to 2/3 of burst pressure" in the coming weeks.
To which this is pressurized air and not cryogenic oxygen or supercooled methane as a test article and not production or to size..

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#32 2018-01-07 10:26:59

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,500

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

louis wrote:

Space X have already conducted pressure tests on their full scale model I believe:


http://uk.businessinsider.com/spacex-ca … st-2016-11


That was done last year before the announced reduction in size. This is now an obsolescent version.

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#33 2018-01-07 12:22:50

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 3,190
Website

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

Safe burst testing requires filling the tank with water and pressurizing that.  When the tank bursts,  the pieces don't accelerate,  they just fall outward,  because water is practically incompressible until you reach around 5-10,000 psi,  and only a handful of percent even at 10,000 psi. 

If you burst test with air (or any other gas),  the compressed pressure is very suddenly released,  and the rapidly-expanding gas accelerates the pieces to high supersonic speeds as very dangerous shrapnel.  (The military fragment impact test is spec'd at 8000 ft/sec precisely because of this effect.)  In the solid rocket motor business,  we never, ever, ever (!!!) proof-tested anything with air or any other gas.  We always used water. 

That testing safety concept comes from relatively early in the boiler design experience,  which is around 3 centuries old now.  I would be most disappointed to learn that Spacex's engineers were unaware of this simple safety expedient that saves lives,  and tons of money.

GW

Last edited by GW Johnson (2018-01-07 12:27:24)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#34 2018-01-07 18:49:00

louis
Member
From: UK
Registered: 2008-03-24
Posts: 3,818

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

Accepted but they are really testing the materials and structure aren't they? A smaller version is unlikely to be less mission-ready. That said, I agree they obviously need to test the actual scale prototype.

Oldfart1939 wrote:
louis wrote:

Space X have already conducted pressure tests on their full scale model I believe:


http://uk.businessinsider.com/spacex-ca … st-2016-11


That was done last year before the announced reduction in size. This is now an obsolescent version.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#35 2018-01-07 23:06:01

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 3,190
Website

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

Well,  you could test for cryogenic effects upon burst pressure by using inert liquid nitrogen,  and still get the benefits of pressurizing with a near-incompressible liquid.  LN2 is cheap.  Not as cheap as water,  but not expensive.

Once you have characterized the cold burst phenomena safely,  you can explore leakage effects with the real materials,  in a whole lot more effective safety.  Leakage is a real concern with composites because they are inherently porous.  There HAS to be some sort of liner. 

Methane isn't a problem beyond leakage with carbon composites,  but oxygen is.  Oxygen spontaneously reacts with carbon,  especially carbon dust.  LOX / charcoal is an old,  almost forgotten high-order detonating explosive.  There HAS to be an isolating,  leak-preventing liner.  And it simply CANNOT fail. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#36 2018-01-08 05:28:12

elderflower
Member
Registered: 2016-06-19
Posts: 879

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

And that liner needs to be an unreactive substance. Copper alloys, Aluminium alloys and austenitic stainless steels (eg type 304) are popular choices. It need only be thin because the structural strength is provided by the overwrap. But if it develops a crack you will be in big trouble. This is possibly what happened to the failed Falcon 9 last year, the one that disassembled itself in an unscheduled manner on the pad.

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#37 2018-01-08 10:07:39

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,500

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

I personally like the concept of a Type 304 stainless steel liner, in spite of the associated weight. Then a spray-on layer of a fluorinated polymer and then the overwrap with carbon fiber for strength. Carbon fiber tanks can be reactive with LOX, which I've ranted about several times on this forum. And on SpaceNews.com, as well.

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#38 2018-02-11 20:40:44

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 12,701

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

With the success of the Falcon 9 Heavy comes the forward thinking Elon Musk and you guessed it the BFR...

SpaceX's 'Falcon' feat may be just a prelude to the main event as Elon Musk looks forward to the Big F---ing Rocket that he says will take humans to the moon and Mars.

171019-bfr-spacex-rocket-mn-1210_6f5c91e9dbee8a4d7d533eb9cd017837.focal-860x430.jpg

As Musk revealed at a post-launch press conference, the Falcon Heavy will be a cargo-hauling workhorse. To deliver humans into space, he said, “we need to be way bigger than that.” BFR is the rocket Musk is counting on to return astronauts to the moon and to ferry colonists to Mars.

That being said as he is trying to send it all in 1 shot....rather than manageable pieces.

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#39 2018-03-27 17:22:43

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 12,701

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

Elon Musk's vision to colonize Mars updated in New Space

In "Making Life Multi-Planetary" Elon Musk, CEO and Lead Designer at SpaceX, presents the updated design for the Big Falcon Rocket (BFR), the powerful rocket intended to propel a newly modified space vehicle to the International Space Station and beyond to fulfill his vision for establishing a human presence on Mars.

The article, a summary of Mr. Musk's presentation at the 68th International Astronautical Congress, is published in New Space, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free on the New Space website.

Mr. Musk not only provides details on the BFR's updated design but, importantly, presents a plan for how to pay for it. He describes the development of a huge carbon fiber tank that is capable of holding the cryogenic liquid oxygen needed to fuel the rocket, and the key to the SpaceX business case, how on orbit refueling will take place.

The article also reports on progress toward perfecting propulsive landing and achieving rendezvous and docking. Included is information on the changes to the vehicle as its design has evolved, and the dramatic differences in payload capabilities between previous and current versions of the vehicle and BFR designs. Mr. Musk summarizes his vision and goals for a future manned Mission to Mars.

"Elon's description of the Big Falcon Rocket, along with the stunning recent success of the Falcon 9 Heavy indicates just how far SpaceX has come in establishing the elements needed to dramatically lower the cost for deep space exploration," says Editor-in-Chief Scott Hubbard, Stanford University.

"I look forward to seeing SpaceX contribute to human exploration as well as near-term science goals like the Mars Sample Return."

Research paper

Raptor engine testing

The next key element is on the engine side. We have to have an extremely efficient engine; the Raptor engine will be the highest thrust-to-weight engine, we believe, of any engine of any kind ever made. We already have 1200 seconds of firing across 42 main engine tests. We have fired Raptor for as long as 100 seconds. It could fire for much longer than 100 seconds, this is just a reflection of the size of the test tanks. The duration of the firing for landing on Mars is about 40 seconds. The test engine currently operates at 200 atmospheres, or 200 bar, the flight engine will be at 250 bar, and then we believe over time we could probably get that to a little over 300 bar.

figure4.gif

Mars mission goals

We are targeting our first cargo missions in 2022—that's not a typo, although it is aspirational. We've already started building the system—the tooling for the main tanks has been ordered, the facility is being built and we will start construction of the first ship around the second quarter of next year. In about six to nine months we should start building the first ship. I feel fairly confident that we can complete the ship and be ready for a launch in about five years. Five years seems like a long time to me. The area under the curve of resources over that period of time should enable this time frame to be met, but if not this time frame, I think pretty soon thereafter. But that is our goal, to try to make the 2022 Mars rendezvous (Fig. 15). The Earth-Mars synchronization happens roughly every two years, so every two years there is an opportunity to fly to Mars.

figure15.gif

Then in 2024 we want to try to fly four ships—two cargo and two crew. The goal of the first mission is to find the best source of water, and for the second mission, the goal is to build the propellant plant. We should—particularly with six ships there—have plenty of landed mass to construct the propellant depot, which will consist of a large array of solar panels, and then everything necessary to mine and refine water, draw the CO2 out of the atmosphere, and then create and store deep cryo CH4 and O2.

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#40 2018-03-28 08:28:03

louis
Member
From: UK
Registered: 2008-03-24
Posts: 3,818

Re: Timeline milestones for a BFR Cargo landing on Mars in 2022.

Wow! So the whole of Mission One would potentially have 600 tonnes of cargo supplies! That is hugely huge!  Think what you can do with 600 tonnes.

Musk's chat over the timeline is as ever somewhat confusing...he seems already to be rowing back and talking about construction of the first ship in the second quarter of next year and his "5 year" timeline takes us to 2023 not 2022. Be that as it may, it's still an impressive  step forward.

So Part A of Mission One - the cargo only landing - is focussed on finding water resources? Is he going to have a number of small rocket hoppers and some robot rovers on board to undertake the prospecting? Rocket hoppers would be well suited as you simply need to open the cargo doors and you could deploy them, without crane or similar. Perhaps they will be combination rocket hoppers/wheeled mini rovers?



SpaceNut wrote:

Elon Musk's vision to colonize Mars updated in New Space

In "Making Life Multi-Planetary" Elon Musk, CEO and Lead Designer at SpaceX, presents the updated design for the Big Falcon Rocket (BFR), the powerful rocket intended to propel a newly modified space vehicle to the International Space Station and beyond to fulfill his vision for establishing a human presence on Mars.

The article, a summary of Mr. Musk's presentation at the 68th International Astronautical Congress, is published in New Space, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free on the New Space website.

Mr. Musk not only provides details on the BFR's updated design but, importantly, presents a plan for how to pay for it. He describes the development of a huge carbon fiber tank that is capable of holding the cryogenic liquid oxygen needed to fuel the rocket, and the key to the SpaceX business case, how on orbit refueling will take place.

The article also reports on progress toward perfecting propulsive landing and achieving rendezvous and docking. Included is information on the changes to the vehicle as its design has evolved, and the dramatic differences in payload capabilities between previous and current versions of the vehicle and BFR designs. Mr. Musk summarizes his vision and goals for a future manned Mission to Mars.

"Elon's description of the Big Falcon Rocket, along with the stunning recent success of the Falcon 9 Heavy indicates just how far SpaceX has come in establishing the elements needed to dramatically lower the cost for deep space exploration," says Editor-in-Chief Scott Hubbard, Stanford University.

"I look forward to seeing SpaceX contribute to human exploration as well as near-term science goals like the Mars Sample Return."

Research paper

Raptor engine testing

The next key element is on the engine side. We have to have an extremely efficient engine; the Raptor engine will be the highest thrust-to-weight engine, we believe, of any engine of any kind ever made. We already have 1200 seconds of firing across 42 main engine tests. We have fired Raptor for as long as 100 seconds. It could fire for much longer than 100 seconds, this is just a reflection of the size of the test tanks. The duration of the firing for landing on Mars is about 40 seconds. The test engine currently operates at 200 atmospheres, or 200 bar, the flight engine will be at 250 bar, and then we believe over time we could probably get that to a little over 300 bar.

https://www.liebertpub.com/na101/home/l … igure4.gif

Mars mission goals

We are targeting our first cargo missions in 2022—that's not a typo, although it is aspirational. We've already started building the system—the tooling for the main tanks has been ordered, the facility is being built and we will start construction of the first ship around the second quarter of next year. In about six to nine months we should start building the first ship. I feel fairly confident that we can complete the ship and be ready for a launch in about five years. Five years seems like a long time to me. The area under the curve of resources over that period of time should enable this time frame to be met, but if not this time frame, I think pretty soon thereafter. But that is our goal, to try to make the 2022 Mars rendezvous (Fig. 15). The Earth-Mars synchronization happens roughly every two years, so every two years there is an opportunity to fly to Mars.

https://www.liebertpub.com/na101/home/l … gure15.gif

Then in 2024 we want to try to fly four ships—two cargo and two crew. The goal of the first mission is to find the best source of water, and for the second mission, the goal is to build the propellant plant. We should—particularly with six ships there—have plenty of landed mass to construct the propellant depot, which will consist of a large array of solar panels, and then everything necessary to mine and refine water, draw the CO2 out of the atmosphere, and then create and store deep cryo CH4 and O2.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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