What makes you think that LockMart and Boeing are incapable of doing what NASA is doing right now?
Quote from: woods170 on 05/18/2017 06:51 amWhat makes you think that LockMart and Boeing are incapable of doing what NASA is doing right now?-Nobody's going to tell them "it's the law".-Nobody's going to pay them upfront.
Quote from: Space Ghost 1962 on 05/17/2017 06:04 pmQuote from: Star One on 05/17/2017 05:08 pmWell maybe it should be more independent or they'll have a dead JV (Joint Venture) on both their hands.Then if they need it they'll revive it from the dead.That doesn't really make sense though. If everyone is laid off, institutional knowledge lost, factories shut down, contractors exit the market etc, they won't be able to just restart production even for the existing proven Atlas V/Delta IV. Seems like Centaur in particular would be extremely difficult to resurrect, and the Russian engine purchases have been grandfathered in but likely wouldn't be allowed to restart. The actual value in ULA would be lost forever even if they played "weekend at Bernies" with the corpse.
Quote from: Star One on 05/17/2017 05:08 pmWell maybe it should be more independent or they'll have a dead JV (Joint Venture) on both their hands.Then if they need it they'll revive it from the dead.
Well maybe it should be more independent or they'll have a dead JV (Joint Venture) on both their hands.
Quote from: ArbitraryConstant on 05/18/2017 07:46 pm-Nobody's going to tell them "it's the law".-Nobody's going to pay them upfront.That was not my point. My point was that Boeing and LockMart can do what NASA is doing right now: re-learn how to build rockets in a (as of yet) theoretical scenario where ULA has been allowed to "die" and - for some reason - needs to be raised from the dead. The keyword here is "need". When there is a corporate need, the order to do something to satisfy that need, and the money to make it so, will eventually follow.
-Nobody's going to tell them "it's the law".-Nobody's going to pay them upfront.
Whichever engine is not selected by United Launch Alliance to power the Vulcan rocket could lose its Air Force funding, although top acquisition officials declined to say Wednesday whether they would definitely take that action.“Once ULA makes their decision, that’s a choice that ULA makes, I’m interested in the launch service capability,” said Maj. Gen. Roger Teague, the director of space programs in the Office of the Assistant Secretary for Acquisition.Speaking to reporters at the Pentagon, Teague declined to say whether the Air Force would cancel funding for the development of whichever engine ULA does not select, but said that the service is focused on launch services rather than engine development.“I’m not going to continue to fund a separate engine that may not be used as part of our overall assured access requirement,” Teague said.
Agreed they would be able to re-learn how to build rockets. ..
I'm hoping neither Boeing nor LM will start 're-learning' rocketry, but just go and snap up one of the new startups and go carefully about augmenting and complementing their capabilities to help them grow up fast.
Are you saying ULA is a prisoner of its parents shortsightedness?
Quote from: ArbitraryConstant on 05/19/2017 01:58 pmAgreed they would be able to re-learn how to build rockets. ..I'm hoping neither Boeing nor LM will start 're-learning' rocketry, but just go and snap up one of the new startups and go carefully about augmenting and complementing their capabilities to help them grow up fast.
Quote from: guckyfan on 05/15/2017 04:28 pmQuote from: TrevorMonty on 05/15/2017 03:59 pmThere is no radiator on ICE.Where does the excess heat go?Back into the propellant and out the thrusters
Quote from: TrevorMonty on 05/15/2017 03:59 pmThere is no radiator on ICE.Where does the excess heat go?
There is no radiator on ICE.
Quote from: Jim on 05/26/2017 08:34 pmQuote from: guckyfan on 05/15/2017 04:28 pmQuote from: TrevorMonty on 05/15/2017 03:59 pmThere is no radiator on ICE.Where does the excess heat go?Back into the propellant and out the thrustersI can not yet see how dumping heat into the propellant during long coast phases is a good idea.
Quote from: guckyfan on 05/27/2017 06:26 amQuote from: Jim on 05/26/2017 08:34 pmQuote from: guckyfan on 05/15/2017 04:28 pmQuote from: TrevorMonty on 05/15/2017 03:59 pmThere is no radiator on ICE.Where does the excess heat go?Back into the propellant and out the thrustersI can not yet see how dumping heat into the propellant during long coast phases is a good idea.They don't dump heat into the propellant in long coast phases. One of the advantages of an IC engine is that its idle power generation can be tiny. So whatever boiloff there is is used to idle the IC engine, giving power for electronics. When they need to re-pressurize the tanks, the crank up the engine.At idle, the left over exhaust gasses are vented overboard. So there is a constant ullage thrust (very low). This keeps the propellants settled, which reduces the boil off a factor of 2 or more.Read the papers. IVF is really good stuff, and applies to either H2 or methane (except that for methane, you can sometimes avoid any boil off at all at higher orbits, or interplanetary flight).Jim
ICEs are cheap and have a much higher power to weight ratio than batteries.Batteries will win for cars because environmental standards are getting tougher and tougher. It's really hard (and expensive) to meet emission standards with ICEs.
Quote from: meekGee on 05/14/2017 08:20 pm- the ICE component of IVF is dated. That means you don't understand IVF. The least benefit of IVF is the power it generates. The ICE provides heat and pressure. The savings is from the elimination of He and hydrazine. IVF doesn't work with fuel cells, the heat of the ICE is needed to make IVF work.
- the ICE component of IVF is dated.
I don't see how electrical driven IVF system is going to be any less complex than ICE driven. All the plumbing, valves, thrusters are same. For electrical system you need a means of heating LH and LOX to gas to pressurise tanks during main engine burn. That is lot of energy required for few minutes. NB ICE does this not main engine (RL10), reducing complexity of main engine. Fuel consumption for power generation during coast phases is less than boil off. Any fuel lost to boiloff that is not burned for thrust or power is lost energy. About only time solar panel makes sense is when all fuel is evaporated and tanks are full of pressured gas. At which point stage has probably been disposed off or docked to fuel depot for future use. The ICE is not a heavy car engine but ultra light motorbike engine.
Helium purge gasses are used to ensure that feed lines are clear of any residual propellants after main engine firings and prior to long duration periods of dormancy.
The integrated RCS system uses accumulator tanks which are sized to hold the propellant required for a single translational maneuver. These accumulator tanks are fed from the main propellant tanks by a set of electric pumps which draw in the appropriate propellant load and provide tank pressurization for operations. This pressurization is supplemented by a gaseous helium system, however, the helium load is greatly reduced due to the smaller accumulator tanks and the electric pumps employed to feed the tanks. From the accumulator tanks to the thruster, the RCS system operates as a traditional regulated pressure-fed system. Propellant flow to the electric pumps is tapped off the flow system used by the CFM circulators which minimizes the number of penetrations into the main propellant tanks.
Here's another interesting system from a NASA design of an in-space stage (serves another purpose of course).https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160012088.pdfIt uses autogenous pressurization when the engines are running, but also helium. Apart from pressurization for clearing feed lines:QuoteHelium purge gasses are used to ensure that feed lines are clear of any residual propellants after main engine firings and prior to long duration periods of dormancy.The RCS:QuoteThe integrated RCS system uses accumulator tanks which are sized to hold the propellant required for a single translational maneuver. These accumulator tanks are fed from the main propellant tanks by a set of electric pumps which draw in the appropriate propellant load and provide tank pressurization for operations. This pressurization is supplemented by a gaseous helium system, however, the helium load is greatly reduced due to the smaller accumulator tanks and the electric pumps employed to feed the tanks. From the accumulator tanks to the thruster, the RCS system operates as a traditional regulated pressure-fed system. Propellant flow to the electric pumps is tapped off the flow system used by the CFM circulators which minimizes the number of penetrations into the main propellant tanks.