Blue Origin Thread (merged)

[Elthy]

Also one is to weak, they would need 3. But since switching to methane would mean to reconstruct the whole rocket this wont happen at all.

[Wjolcz]

9 minutes ago, Elthy said:

Also one is to weak, they would need 3. But since switching to methane would mean to reconstruct the whole rocket this wont happen at all.

Yeah, that's what I thought. Would be cool to see F9 use one engine instead of nine some day though.

[tater]

Stage 2 might benefit from a single raptor in place of the Merlin, if for no other reason than no COPV  .

[Nibb31]

2 hours ago, wumpus said:

They may have to,  but they also might simply throw away a "used up" ITS after n flights.  Perhaps some modules will have longer lifecycles than others and they will detach and deorbit certain modules and replace them, leaving other older parts to go back to Mars.  Certainly, the lion's share of the cost will getting the thing from Earth to LEO, so they don't want to do that any more times than necessary (regardless of how many times the BFR can be reused).

Landing a ITS on Earth seems like the option they will avoid as long as they can.

No, because they have a booster specifically designed to launch ITS vehicle into orbit for a low cost.

And direct reentry and landing from Mars costs less dV than an orbital insertion burn.

[tater]

@Nibb31 is right. The whole idea is that the ITS does a direct EDL from Mars (and to Mars, I imagine). The goal is spending as little dv as possible.

Testing this thing could be expensive if there are any failures. You'd want to test it all up to LEO. You'd want to test a LEO reentry ad landing. You'd want to throw the thing far enough out to get an idea of a direct entry from at least the Moon, or even accelerating it to fake an EDL direct from Mars.

You might use that same Earth reentry vehicle as a test on orbit for a while, too. Keep a small crew aboard for a long time in LEO, perhaps, then remove the crew with a crew rated vehicle (D2), and then boost the ITS for a fast reentry.

You'd need to send one unmanned to Mars, as well.

[Motokid600]

Honestly I'm just really curious as to how they plan on getting 100 people down from the rocket to the surface. "Okay folks, weve arrived. It took us decades and the most cutting edge tech there is... okay now help me with the rope ladder."

Edited September 30, 2016 by Motokid600

[tater]

Winch and a crew/cargo gondola, I bet.

I sorta like that it's devolving back to the 1950s. Rockets landing on tongues of fire like god and Heinlein intended.

[sojourner]

A lift platform that uses one of the legs as a traverse?

[Motokid600]

Hell if it didn't need refuel it could almost be the new NOVA Mars direct descent. The 1950 way of doing it and Nova didn't last long before being reevaluated. The same will most likely happen here I figure. Elon Musk is playing the role of a modern-day Von Braun with his vast orbital stations and nuclear reactors. In the end the final rendition will be a farcry from the original. I personally much prefer the Aldrin cycler approach. Simple craft, high radiation protection, No aerodynamic stresses, an vastly more simple landing/ascent craft... But we will STILL need the massive rocket to dock cargo to the ship moving at escape velocity. So this 550t to LEO rocket wil still be of significant use. And we ensure a steady line of Mars resupply.

[sojourner]

There are rumors of a raptor based second stage in development, but nothing concrete that I've seen.

[sojourner]

1 minute ago, Motokid600 said:

In the end the final rendition will be a farcry from the original.

Except, according to Musk, what we've been shown is based on the engineering drawings.  So it may not be that far off in overall design even if the details change.

[Motokid600]

33 minutes ago, sojourner said:

Except, according to Musk, what we've been shown is based on the engineering drawings.  So it may not be that far off in overall design even if the details change.

With the present plan, yea. If they eventually go with a cycler method that'd change it a good deal. 146 day transit time for one. The "ITS" could be WAY smaller for the 100 people being only a very large Dragon that goes up to the cycler ship, lands on Mars, goes up to the cycler ship, lands on Earth and on and on. The cycler would be just a simple big structure covered in solar panels and radiators.  A hotel with a station keeping system and life support for under a year. ( Supplied by the manned launch. The idea here is no need for "room". Pack 'em in it'll only be a few hours. ) A more expensive initial investment yes, but once the ship is kicked out onto the proper trajectory your done. Especially if you want to do two like the plan says. One inbound and one outbound.    .... Folks i'm having a hard time wondering why they chose against this o.O

 

 

Edited September 30, 2016 by Motokid600

[DerekL1963]

30 minutes ago, sojourner said:

Except, according to Musk, what we've been shown is based on the engineering drawings.  So it may not be that far off in overall design even if the details change.

They had engineering drawings for the Nova (as a direct ascent to the Moon), and for the lander it carried (which made a direct landing on the Moon and a direct ascent back to Earth) too.   That's not what flew though.

 

[Motokid600]

Will the real Dr. John Houbolt please stand up.

[sojourner]

54 minutes ago, Motokid600 said:

With the present plan, yea. If they eventually go with a cycler method that'd change it a good deal. 146 day transit time for one. The "ITS" could be WAY smaller for the 100 people being only a very large Dragon that goes up to the cycler ship, lands on Mars, goes up to the cycler ship, lands on Earth and on and on. The cycler would be just a simple big structure covered in solar panels and radiators.  A hotel with a station keeping system and life support for under a year. ( Supplied by the manned launch. The idea here is no need for "room". Pack 'em in it'll only be a few hours. ) A more expensive initial investment yes, but once the ship is kicked out onto the proper trajectory your done. Especially if you want to do two like the plan says. One inbound and one outbound.    .... Folks i'm having a hard time wondering why they chose against this o.O

Do you really think they waited this long to announce their plan without considering and dismissing a cycler system?

[Motokid600]

Just now, sojourner said:

Do you really think they waited this long to announce their plan without considering and dismissing a cycler system?

I'm wondering what possible reason they could have to justify that dismissal.

[Vanamonde]

A multitude of SpaceX-related threads have been merged. 

[Elthy]

You would still need the DeltaV for a cycler, the only thing you save is the regenerative pard of the lifesupport system. Not realy worth it.

[Motokid600]

5 hours ago, Elthy said:

You would still need the DeltaV for a cycler, the only thing you save is the regenerative pard of the lifesupport system. Not realy worth it.

Your saving the mass of having to launch a giant, ridiculous all in one cruise ship out of Earths and Mars gravityb well each and every time. With a cycler you only need to do that once and your done. The ITS can then be massively simplified making that Dv much easier and cheaper to achieve.

Edited September 30, 2016 by Motokid600

[Nibb31]

15 minutes ago, Motokid600 said:

Your saving the mass of having to launch a giant, ridiculous all in one cruise ship out of Earths and Mars gravityb well each and every time. With a cycler you only need to do that once and your done. The ITS can then be massively simplified making that Dv much easier and cheaper to achieve.

The trajectory of a cycler isn't necessarily as quick as a direct transfer. Therefore, transit times are typically longer, which means that you need more supplies and consumables.

The only thing a cycler saves is the mass of a higher habitable volume. RV with the cycler would still be a matter of several days, so you can't really cram 100 people into seats like you would in a 737. You are still going to need some ample room in your shuttle craft.

If anything, a cycler might make sense as a much later optimisation, when you need to transport thousands of passengers. We aren't there yet. Even planning more than 10 is ridiculous it at this stage.

[Motokid600]

Aldrin cylcer calls for 146 day transit time. People aren't on board for the entire duration of its orbit. They depart to Mars as it passes by and catch it 16 months later on the way back in for 146 day trip back. You think it'd take days to rendezvous with a craft on an escape trajectory? Surely that could be reduced. And... Yea I don't understand the 100 person deal. It's a big pretty number, but c'mon can we get 70... 80 maybe lol.

[Technical Ben]

Space. In space it is a premium.

[magnemoe]

52 minutes ago, Nibb31 said:

The trajectory of a cycler isn't necessarily as quick as a direct transfer. Therefore, transit times are typically longer, which means that you need more supplies and consumables.

The only thing a cycler saves is the mass of a higher habitable volume. RV with the cycler would still be a matter of several days, so you can't really cram 100 people into seats like you would in a 737. You are still going to need some ample room in your shuttle craft.

If anything, a cycler might make sense as a much later optimisation, when you need to transport thousands of passengers. We aren't there yet. Even planning more than 10 is ridiculous it at this stage.

No not coach class but not cabins, gravity or lots of radiation shielding either.
I agree it would not be needed for an one time mars mission but for the 100 person version it would make sense. 
For direct transfer it limited how fast you can go using chemical engines and earobraking. 

[Kryten]

12 hours ago, sojourner said:

There are rumors of a raptor based second stage in development, but nothing concrete that I've seen.

There is a USAF contract for development of a raptor second stage for FH, but it's not very big, and it remains doubtful that it will actually fly. Basically it's money the USAF had left over in their 'next-gen launcher' budget after paying for AR-1.

[Exoscientist]

23 hours ago, Nibb31 said:

I wish people would stop talking about SSTO. There is no SSTO in any part of Musk's plans, except the direct launch from Mars surface.

The ITS booster is nowhere near SSTO. It separates at around 2500m/s. The whole point of refueling the ITS in LEO is because it burns all of its propellant to reach LEO.

 Actually, there is. In his presentation at about the 54 minute mark Musk discusses that the second stage in its tanker form or in its spaceship form will be able to reach orbit when used as a single stage. He states though the tanker will not be able to land, presumably because of insufficient reserve fuel. Then it could be an expendable SSTO.

However, he states it could be used as cargo ship for fast intercontinental deliveries. In this case it would need to land so presumably he means this would be at speeds just below orbital.

 

  Bob Clark