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Blue Origin Thread (merged)

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1 hour ago, kerbiloid said:

While Dragon prepares to reach the Moon in 2018,  in NASA

I find such lack of faith disturbing...

Why? Those additionnal flights were made possible by of the reduction in the Russian crews (from 3 to 2), due to budget cuts. So instead of flying some Soyuz missions with only 2 crew members, NASA purchased the third seat.

Also both Dragon 2 and CST-100 are intended to do their first manned flight in May, resp. August 2018. CST-100s first flight to ISS is even only scheduled for December 2018.

In short, the flights that NASA booked now will occur before Dragon and CST-100 can fly according to a regular schedule to ISS. And the option of the 2019 flights is if the schedules at SpaceX or Boeing will slip.

Considering that by this 4 out of 6 permanent crew members will either be US or from US partners, there is maybe more available for SpaceX and Boeing than replacing 2 out of 4 Soyuz flights done every year.

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I have no doubt that CST-100 will fly in 1-2 years.
But afaik before conquering the Moon in 2018, SpaceX has 2 or 3 booked ISS crewed flights, on a spaceship yet haven't flown. Probably, SpaceX personnel should work 24/7 25/8 to reach the Moon.

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Boeing owns several Soyuz seats because they were part of an agreement over the debt from sea launch. It has nothing to do with Starliner.

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57 minutes ago, Veeltch said:

But that leaves me thinking on top of what rocket will Starliner be launched?

Atlas V

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Posted (edited)

This might be doable with a single Falcon 9 v1.2 and Dragon V2:

According to the SpaceX site, the F9 v1.2 can get 8,300 kg, 18,300 lb, to geosynchronous transfer orbit (GTO).

GTO is an intermediate orbit to GEO frequently used for communications satellites.

It takes about 2,500 delta-v to get to GTO and about 3,100 m/s delta-v to reach the Moon, translunar injection. So you would need about 600 m/s additional delta-v to get to the Moon.

The Dragon V2 is said to carry 1,390 kg of propellant for its Superdraco thrusters. The Isp of the Superdracos is only 240s at sea level. But with just a nozzle extension we can get the vacuum Isp to the 320 s range.

Then the delta-v possible for a 6,400 metric ton dry mass Dragon V2 would be:

320*9.81ln(1 + 1,390/(6400)) = 616.9 m/s.

This is just barely enough. But rocket engineers always like to carry some extra fuel on flights. Also that calculation doesn't even include the weight of the astronauts. We could store some extra fuel in the trunk of the Dragon. If we had 1,600 kg total propellant in the Dragon and trunk then we could get a delta-v of

320*9.81ln(1 + 1,600/(6400 +200)) = 681 m/s.

This would allow 200 kg more for the astronauts and supplies.

 

  Bob Clark

Edited by Exoscientist

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8 minutes ago, Exoscientist said:

This might be doable with a single Falcon 9 v1.2 and Dragon V2:

According to the SpaceX site, the F9 v1.2 can get 8,300 kg, 18,300 lb, to geosynchronous transfer orbit (GTO).

GTO is an intermediate orbit to GEO frequently used for communications satellites.

It takes about 2,500 delta-v to get to GTO and about 3,100 m/s delta-v to get to reach the Moon, translunar injection. So you would need about 600 m/s additional delta-v to get to the Moon.

The Dragon V2 is said to carry 1,390 kg of propellant for its Superdraco thrusters. The Isp of the Superdracos is only 240s at sea level. But with just a nozzle extension we can get the vacuum Isp to the 320 s range.

Then the delta-v possible for a 6,400 metric ton dry mass Dragon V2 would be:

320*9.81ln(1 + 1,390/(6400)) = 616.9 m/s.

This is just barely enough. But rocket engineers always like to carry some extra fuel on flights. Also that calculation doesn't even include the weight of the astronauts. We could store some extra fuel in the trunk of the Dragon. If we had 1,600 kg total propellant in the Dragon and trunk then we could get a delta-v of

320*9.81ln(1 + 1,600/(6400 +200)) = 681 m/s.

This would allow 200 kg more for the astronauts and supplies.

 

  Bob Clark

What if they used expendable F9 FT and use every single litre of fuel the second stage carries? AFAIK it always has some spare fuel they use to deorbit it after GTO missions. Since this would be a free-return trajectory the second stage would fly by the Moon, go back and burn in the atmosphere anyway.

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15 minutes ago, Exoscientist said:

This might be doable with a single Falcon 9 v1.2 and Dragon V2:

According to the SpaceX site, the F9 v1.2 can get 8,300 kg, 18,300 lb, to geosynchronous transfer orbit (GTO).

GTO is an intermediate orbit to GEO frequently used for communications satellites.

It takes about 2,500 delta-v to get to GTO and about 3,100 m/s delta-v to get to reach the Moon, translunar injection. So you would need about 600 m/s additional delta-v to get to the Moon.

The Dragon V2 is said to carry 1,390 kg of propellant for its Superdraco thrusters. The Isp of the Superdracos is only 240s at sea level. But with just a nozzle extension we can get the vacuum Isp to the 320 s range.

Then the delta-v possible for a 6,400 metric ton dry mass Dragon V2 would be:

320*9.81ln(1 + 1,390/(6400)) = 616.9 m/s.

This is just barely enough. But rocket engineers always like to carry some extra fuel on flights. Also that calculation doesn't even include the weight of the astronauts. We could store some extra fuel in the trunk of the Dragon. If we had 1,600 kg total propellant in the Dragon and trunk then we could get a delta-v of

320*9.81ln(1 + 1,600/(6400 +200)) = 681 m/s.

This would allow 200 kg more for the astronauts and supplies.

 

  Bob Clark

There may be something more to this that we can't see, because SpaceX has already confirmed that this will fly on Falcon Heavy. Perhaps the customers want the propulsive landing experience, so the SuperDracons can't be used for in-space propulsion? </speculation>

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Probably an impossible idea: but couldn't they rework the the upper stage, to be able to be robotically refueled? And device a way to make the the Merlin 1D Vac not freeze up so it can be easily restarted.

Launch a refueling craft to GTO (or what is useful) and let the Moon mission rendezvous with it. Robotically refuel it's second stage and progress with the mission.

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Posted (edited)
10 minutes ago, Gkirmathal said:

Probably an impossible idea: but couldn't they rework the the upper stage, to be able to be robotically refueled? And device a way to make the the Merlin 1D Vac not freeze up so it can be easily restarted.

Launch a refueling craft to GTO (or what is useful) and let the Moon mission rendezvous with it. Robotically refuel it's second stage and progress with the mission.

Space X yet haven't docked to ISS even once. All Dragons have been berthed by an arm.

http://www.floridatoday.com/story/tech/science/space/spacex/2017/02/23/spacex-dragon-arrives-safely-iss/98290822/

Edited by kerbiloid

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21 minutes ago, Streetwind said:

There may be something more to this that we can't see, because SpaceX has already confirmed that this will fly on Falcon Heavy. Perhaps the customers want the propulsive landing experience, so the SuperDracons can't be used for in-space propulsion? </speculation>

Probably as the margins on using an falcon 9 is to small. vacuum isp might well be lower. 
Sending an unmanned dragon 2 around the moon with falcon heavy would also be an nice way to test both systems.
Now I would liked to enter an moon orbit to get more quality time but not sure about dV requirements here. 
 

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1 minute ago, kerbiloid said:

Space X yet haven't docked to ISS even once. All Dragons have been berthed by an arm.

Yes yes I know :)

That's why I asked the question, cause they want to develop such refueling tech for their Mars space ship concept. So maybe they could start of small, with this by developing such tech and adopting it to current F9 upper stage.

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They can add arms to the Dragon-2: to berth itself to ISS or to catch the refueling barrel.

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Posted (edited)

One large, overly muscly arm ought to be enough for that, yeah.

 

(Oh lord am I dating myself? :P)

 

Edited by Streetwind

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Posted (edited)
59 minutes ago, Streetwind said:

There may be something more to this that we can't see, because SpaceX has already confirmed that this will fly on Falcon Heavy. Perhaps the customers want the propulsive landing experience, so the SuperDracons can't be used for in-space propulsion? </speculation>

 The Isp (specific impulse) of the Superdracos is pretty poor, only 240s at sea level. This means they would be too inefficient to use in vacuum. You would have to use nozzle extensions for this plan to work.

 That would be extra development work on the Dragon. Perhaps SpaceX just wants to take the simple approach of just using the Falcon Heavy. However, I'm not too sanguine on using the FH on a manned mission when it will have such few flights behind it. 

 

  Bob Clark

Edited by Exoscientist

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30 minutes ago, magnemoe said:

Probably as the margins on using an falcon 9 is to small. vacuum isp might well be lower. 
Sending an unmanned dragon 2 around the moon with falcon heavy would also be an nice way to test both systems.
Now I would liked to enter an moon orbit to get more quality time but not sure about dV requirements here. 
 

 For an unmanned test mission I'd much prefer it to actually land on the Moon such as in the permanently shadowed craters believed to contain ice.

  Bob Clark

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Posted (edited)
2 hours ago, Gkirmathal said:

Probably an impossible idea: but couldn't they rework the the upper stage, to be able to be robotically refueled? And device a way to make the the Merlin 1D Vac not freeze up so it can be easily restarted.

Launch a refueling craft to GTO (or what is useful) and let the Moon mission rendezvous with it. Robotically refuel it's second stage and progress with the mission.

You need to :

- Create a fuel duct between stages

- Pump cryogenic fuel through that (both RP-1 and LOX)

- Also refill the pressurant.

I think... that's over the top for a little result. Soyuz was able to do that, but it had hypergolic fuels w/o pressurant instead (which, probably only corrosive, not explosive).

Edited by YNM

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2 hours ago, Gkirmathal said:

Probably an impossible idea: but couldn't they rework the the upper stage, to be able to be robotically refueled? And device a way to make the the Merlin 1D Vac not freeze up so it can be easily restarted.

Launch a refueling craft to GTO (or what is useful) and let the Moon mission rendezvous with it. Robotically refuel it's second stage and progress with the mission.

That would require designing a whole new upper stage, as well as a whole new refueling vehicle. That would take years of development and would side track all their other projects.

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5 minutes ago, Nibb31 said:

That would require designing a whole new upper stage, as well as a whole new refueling vehicle. That would take years of development and would side track all their other projects.

Yea, at that point you might as well make it the Falcon/Raptor Upperstage people have been speculating about since the AF contract was bandied about.

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Posted (edited)

Refueling in space with cryogens hasn't been done; only with N2O4, UDMH, and ethanol. It's going to be doable, and several groups are working on it, but it's not going to be easy to develop.

Edited by Kryten

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5 hours ago, Exoscientist said:

The Isp of the Superdracos is only 240s at sea level. But with just a nozzle extension we can get the vacuum Isp to the 320 s range.

The Superdracos are the Dragon V2's launch escape system. The thing that saves the astronauts life if everything else goes horribly wrong. SpaceX won't start messing around with that lightly.

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33 minutes ago, cantab said:

The Superdracos are the Dragon V2's launch escape system. The thing that saves the astronauts life if everything else goes horribly wrong. SpaceX won't start messing around with that lightly.

At least for any varient that actually launches crew.

A hypothetical lunar lander varient of Dragon 2 (White dragon) that goes up unmanned for a 1-way landing on the moon has less need for a launch abort system.

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1 hour ago, cantab said:

The Superdracos are the Dragon V2's launch escape system. The thing that saves the astronauts life if everything else goes horribly wrong. SpaceX won't start messing around with that lightly.

I'd bet that there's a variant of the dragon trunk sitting somewhere at Hawthorne that has Hypergol tanks and Super-Draco engine mounted in place of cargo capability

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There might be a sketch of one somewhere. But not actual hardware.

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2 minutes ago, sojourner said:

There might be a sketch of one somewhere. But not actual hardware.

Why not, it's a logical thing to test and prove possible

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12 minutes ago, Nothalogh said:

Why not, it's a logical thing to test and prove possible

Because it's very expensive to design and build the hardware just to test that.

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