Falcon Heavy for Moon, Mars, and More?

Oldfart1939 · 2018-02-18 22:36:56

This is a new thread started in response to the direction the Unmanned Probes thread regarding Falcon Heavy has taken. Robert Zubrin wasted no time in writing his opinion in regards to the possible utility of the FH for missions beyond LEO.

http://www.weeklystandard.com/what-the- … ce9cd02e34

SpaceNut: I agree with you about the small diameter (3.7 meters, or 12 feet) of the FH being a limiting factor for building a manned vehicle for Mars missions. One thing this system has demonstrated is the feasibility of constructing a 3 stick launcher, all being liquid fueled. The lighting of 27 engines DIDN'T BLOW UP the launch vehicle!! So...why not build a more robust, larger diameter center core with 15 engines that is 6.1 meters (20.00 feet) diameter? Since SpaceX had to completely redesign the center core to withstand the additional structural loadings, why not take another step in that direction and improve the basic Falcon Heavy to a Falcon Super Heavy? This would be a "evolutionary approach" rather than a "revolutionary" one?

kbd512 · 2018-03-17 14:32:51

Oldfart1939,

I think that's what the latest incarnation of BFR is. F9H is an evolutionary step towards a truly reusable two stage super heavy lift launch vehicle. If anything, BFR is a simplified approach using slightly more energetic propellants and a booster design that lowers maintenance and fuel costs.

louis · 2018-03-17 16:50:14

The (current) BFR design hasn't just popped out of nowhere. It has evolved in response to the perceived demands of the Mars Mission and Space X's space business requirements (huge synergy if it can be used for several purposes) . The fact is that the BFR solution can deliver 300 tonnes in two cargo loads to the Mars surface - which will be an absolutely stunning achievement and be a huge boost to colonisation.

kbd512 wrote:

Oldfart1939,
I think that's what the latest incarnation of BFR is. F9H is an evolutionary step towards a truly reusable two stage super heavy lift launch vehicle. If anything, BFR is a simplified approach using slightly more energetic propellants and a booster design that lowers maintenance and fuel costs.

kbd512 · 2018-03-17 20:52:01

Louis,

At no time in history, past or present, have humans delivered commercial satellites using super heavy lift launch vehicles. If SpaceX can do it, then more power to them. I don't see it as a practical solution unless the means to change orbits without using propellant is available since satellites are delivered to specific orbits. If we had some sort of operational system for changing orbits without using propellants, like electrodynamic tethers or EM / Cannae Drive, for example, then I could see this concept working in SpaceX's favor. Until then, I see BFR, SLS, and similarly sized launch vehicles as being more useful for space exploration than any other purpose. Maybe I'm wrong, and hope I am, but I kinda doubt it. There are operational reasons for why we do things the way we do them.

louis · 2018-03-18 11:57:27

You've lost me there...why couldn't the BFR launch a satellite to orbit if it is designed to also reach the ISS?

kbd512 wrote:

Louis,
At no time in history, past or present, have humans delivered commercial satellites using super heavy lift launch vehicles. If SpaceX can do it, then more power to them. I don't see it as a practical solution unless the means to change orbits without using propellant is available since satellites are delivered to specific orbits. If we had some sort of operational system for changing orbits without using propellants, like electrodynamic tethers or EM / Cannae Drive, for example, then I could see this concept working in SpaceX's favor. Until then, I see BFR, SLS, and similarly sized launch vehicles as being more useful for space exploration than any other purpose. Maybe I'm wrong, and hope I am, but I kinda doubt it. There are operational reasons for why we do things the way we do them.

Terraformer · 2018-03-18 12:19:10

You could, but we don't have any satellites that would use a significant fraction of the payload capacity, so the vast majority of the payload would be wasted. It would be cheaper to use a smaller vehicle.

If you're launching lots of satellites into similar orbits, you could use multiple upper stages, I suppose.

Void · 2018-03-18 14:08:19

Well, I have to disagree with that.

For regular BFR, for some time SpaceX will be launching its own, for broadband.

After that, they will need to replace or upgrade their broadband orbiters.

As for the refueling ship, I should think it could accommodate the odd small payload or two.

As for the Moon and other destinations, I can imagine parking extra supplies in LEO, on a pallet.

For landing on the Moon, then attach the perhaps toroidal pallet to the BFR, up to it's safe landing capacity, and land on the Moon. It should be possible to use such a pallet to actually stabilize the BFR when it lands on the Moon, a broader base.

Further stockpile supplies for a mission to Mars with an exterior pallet. You most likely cannot land on Mars with that, but perhaps like the SpaceX Fairings, the pallet may have thrusters, to insert it into Martian orbit, even if BFR is going to do a tense atmospheric burn-in.

kbd512 · 2018-03-18 15:22:32

Louis,

It's not that you couldn't use BFR to launch satellites, but how would you do that without redesigning the upper stage specifically for that purpose? SpaceX could design three different variants of the upper stage just to launch satellites, but there's a cost associated with doing that. That'd invariably cost more, so they'd simply have to eat the cost of designing, testing, and using a purpose built satellite launcher and obtain enough orders for satellites going to the same or very similar orbits for that to work. Again, if there was a system for changing orbits without using propellants, such as electrodynamic tethers, then a one-size-fits-all launch vehicle solution becomes a much better proposition.

The latest BFR incarnation is a reusable Saturn V class launch vehicle. Historically, NASA has been the only user of such a launch vehicle. The Saturn V, STS, and SLS are all super heavy lift vehicles. The orbiter was part of the STS "payload", since it went all the way to orbit, it just wasn't useful payload, apart from providing the astronauts a place to live in space before ISS was built.

If there's no means to change orbits without using propellants, the satellite operators aren't going to pony up millions to tens of millions in extra money for separate upper stages to make orbit changes when cheaper alternatives are available. This idea has been proposed before and was DOA back then for exactly the reasons I stated. What's changed about changing orbits without using propellants when using BFR versus all the other times this has been proposed or actually attempted? STS used upper stages to launch military satellites to GEO and the upper stages were and are so expensive that there were basically no other takers and even NASA used different vehicles for most of its satellites because the design requirements were not compatible with using STS. That was a government spending program to maintain our technology base during the 1970's and 1980's. SpaceX is a private corporation that has to make a profit to continue operations.

For a corporation, "I think this is cool" is not a valid reason to spend tens of millions of dollars over and above other existing solutions to the same problem. You don't seem willing to accept that, but SpaceX has to get its customers onboard or it has to be willing to eat the entire cost of the design, development, and testing program, which is exactly what it had to do to get Falcon Heavy off the ground. In short, this BFR is a single purpose solution for space exploration purposes. It won't have any other practical purposes because there aren't any.

New Mars Forums

Announcement

#1 2018-02-18 22:36:56

Falcon Heavy for Moon, Mars, and More?

#2 2018-03-17 14:32:51

Re: Falcon Heavy for Moon, Mars, and More?

#3 2018-03-17 16:50:14

Re: Falcon Heavy for Moon, Mars, and More?

#4 2018-03-17 20:52:01

Re: Falcon Heavy for Moon, Mars, and More?

#5 2018-03-18 11:57:27

Re: Falcon Heavy for Moon, Mars, and More?

#6 2018-03-18 12:19:10

Re: Falcon Heavy for Moon, Mars, and More?

#7 2018-03-18 14:08:19

Re: Falcon Heavy for Moon, Mars, and More?

#8 2018-03-18 15:22:32

Re: Falcon Heavy for Moon, Mars, and More?

Board footer