SpaceX News

[Skipjack]

SpaceX is not going to be a monopoly. Blue Origin is already working on a competing RLV.
Of course the prices will be lower for launches that allow them to reuse the hardware afterwards versus launches that have such high payloads or orbits that require them to expend the booster. The prices on the SpaceX website are for payloads with enough margins for landing the booster for later reuse.
In the beginning they will charge significantly less for flights that use previously flown boosters until they have built enough confidence with customers that the reused boosters are just as safe as the new ones. Once the technology is matured enough, reused boosters will be safer than previously unflown boosters and the safety curve will match a bathtub. That means that first flights of a new booster will have a higher chance of failure than previously flown boosters, just like it is for airplanes.
SpaceX has to lower the launch prices to the point where the market elasticity increases enough to give them enough payloads a year. This is why SpaceX will continue to push the prices down. Without extremely low launch prices and extremely frequent flights (Musk eventually wants to launch once a day), there is no basis for mars colonization.

[Maui]

Well,to be fair, monopolies can be influenced by government, but not always to the monopolizers benefit. The monopoly breaking US government actions at the beginning of the 20th century are examples. Admittedly, such actions are often (sometimes?) driven by public opinion more than government competence.

Funny, because I feel these days that gov has been on the side of protecting monopolies as much as breaking them up. It seems rare that worrisome mergers are denied, for SpaceX specifically there was recently the ULA "block buy" issue with the Air Force (broken probably mostly by the public opinion factor you mention), there's states passing laws to block Tesla's sales model, utility commissions preventing Google from using telephone poles for Google Fiber...

[Carl White]

SpaceX is not going to be a monopoly. Blue Origin is already working on a competing RLV.

SpaceX seems to have a big head start though, seeing as Blue Origin has never reached orbit.

[Skipjack]

SpaceX is not going to be a monopoly. Blue Origin is already working on a competing RLV.

SpaceX seems to have a big head start though, seeing as Blue Origin has never reached orbit.

True, but they are working on their next engine (also methane like SpaceX's upcoming raptor) and seem to be very close with it. Then they will build a two stage LV simillar to F9 but with the methane engine.

[paperburn1]

yes but big blue and spacex are looking into methane for two different reasons. Musk wants a round trip from mars. so The Sabatier reaction has been proposed as a key step in reducing the cost of manned exploration of Mars (Mars Direct) through In-Situ Resource Utilization.
A variation of the basic Sabatier methanation reaction may be used via a mixed catalyst bed and a reverse water gas shift in a single reactor to produce methane from the raw materials available on Mars, utilizing water from the Martian subsoil and carbon dioxide in the Martian atmosphere. A 2011 prototype test operation that harvested CO2 from a simulated Martian atmosphere and reacted it with H2, produced methane rocket propellant at a rate of 1 kg/day, operating autonomously for 5 consecutive days, maintaining a nearly 100% conversion rate. An optimized system of this design massing 50 kg "is projected to produce 1 kg/day of O2:CH4 propellant ... with a methane purity of 98+% while consuming 700 Watts of electrical power." Overall unit conversion rate expected from the optimized system is one tonne of propellant per 17 MWh energy input.

[krenshala]

50kg for the converter? That's pretty low mass, considering what it will be doing.

[D Tibbets]

"One tonne of fuel from 17 MWhr of electricity" ... I suppose large solar farms could provide for adequate fuel production in a timely manner. But a Bussard Polywell fusion reactor or one of it's competitors would be tremendously useful. And this is only for an energy source consideration. A fusion powered electric rocket or (drool ) a diluted fusion product rocket would change the game even more.

Despite this wishing (one day soon now), SpaceX strategies based on demonstrated available technology is extremely impressive!

Dan Tibbets

[Skipjack]

yes but big blue and spacex are looking into methane for two different reasons. Musk wants a round trip from mars. so The Sabatier reaction has been proposed as a key step in reducing the cost of manned exploration of Mars (Mars Direct) through In-Situ Resource Utilization.
A variation of the basic Sabatier methanation reaction may be used via a mixed catalyst bed and a reverse water gas shift in a single reactor to produce methane from the raw materials available on Mars, utilizing water from the Martian subsoil and carbon dioxide in the Martian atmosphere. A 2011 prototype test operation that harvested CO2 from a simulated Martian atmosphere and reacted it with H2, produced methane rocket propellant at a rate of 1 kg/day, operating autonomously for 5 consecutive days, maintaining a nearly 100% conversion rate. An optimized system of this design massing 50 kg "is projected to produce 1 kg/day of O2:CH4 propellant ... with a methane purity of 98+% while consuming 700 Watts of electrical power." Overall unit conversion rate expected from the optimized system is one tonne of propellant per 17 MWh energy input.

It is not just for the ISRU. Methane has several other advantages. It produces less soot, so the engines will remain cleaner and will require less maintenance when reused. Current Merlin engines should be good for 10 flights without maintenance. Will probably need deep cleaning especially of the fine cooling channels after that because of the soot deposits. Methalox engines should run much cleaner and probably wont need cleaning for 20 launches or more.
Methalox has a higher Isp than kerolox. This means more payload, especially to higher orbits and BEO (mars, but also moon and others).

[hanelyp]

Methane also has bulkier tankage than kerosene, which offsets the ISP advantage. But the potential for production on Mars and less soot production are clear wins for Methane.

[krenshala]

Clearly the simplified fuel storage and improved Isp makes up for the extra mass requirements (assuming it masses more, and isn't just higher volume).

[TDPerk]

50kg for the converter? That's pretty low mass, considering what it will be doing.

If it makes 1 kg an hour, by the time a commonly quoted Mars Transit cycle of 2 Earth years has passed, it will have made 30,000 pounds, throwing in some extra for losses to be conservative.

[paperburn1]

So this use NASA's space MAV as the example vehicle of what we want to return from Mars's surface. I think they consider the lander vehicle to be about 16 tons of what they will be landing on through the surface of Mars. So figuring they'll abandon as much stuff as they can for the return flight you're looking at maybe 12 tons to be brought backup and orbit. This will give us about a need of 60,000 pounds of fuel/oxidizer to take our intrepid explorers backup to the return vehicle. So we might need 2 of them little gizmos instead of one.

[Skipjack]

Methane also has bulkier tankage than kerosene, which offsets the ISP advantage. But the potential for production on Mars and less soot production are clear wins for Methane.

The lower density is not bad enough to offset the Isp advantage, especially not with the extremely low mass stages that SpaceX has been able to achieve.
This is further mitigated with subcooling and densification of the methane.
There are a few more advantages that further lower the tank mass. The methane is self pressurizing and thus does not require separate helium tanks (with the accompanying support structure for them) to pressurize the tanks. The methane is about the same temperature as the LOX and thus there is less insulations required on the common bulkhead that separates the tanks. All that will mean a good increase in mass fraction over kerolox for LEO and a much larger increase for GTO and BEO missions. The reason is that for the second stage Isp becomes more important once you get to higher orbits.

[Skipjack]

50kg for the converter? That's pretty low mass, considering what it will be doing.

If it makes 1 kg an hour, by the time a commonly quoted Mars Transit cycle of 2 Earth years has passed, it will have made 30,000 pounds, throwing in some extra for losses to be conservative.

Musk wants a 3 month trip (and 30 days in the more distant future). This is quite ambitious but makes perfect sense to me. In fact, I have been arguing that a serious mars colony can not be sustained with trip times longer than 2 weeks (under optimal conditions, which means much longer average trip times). I would presume that they dont stay for 2 years on their first mission there, but rather just for a few days. They will have a precursor mission two years before that though. That one will probably bring the methane converters or just some additional fuel that they will pump into the MCT for the flight home.

[paperburn1]

http://fortune.com/2016/07/30/spacex-te ... -falcon-9/


Successful This time, the three-minute burn was about what it would have taken to get the rocket back into space.