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Old 04-13-2019, 06:16 AM
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blackshire blackshire is offline
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Default FH replaces SLS? (link)

Hello All,

The recent White House directive to return U.S. astronauts to the Moon within five years (for which, Vice President Mike Pence emphasized, achieving the goal takes precedence over the means, utilizing privately-developed rockets if that route will enable the timetable to be met) has caused NASA to consider using the SpaceX Falcon Heavy, topped by a hydrolox (LOX/LH2)-powered Interim Cryogenic Propulsion Stage (ICPS, a modified Delta IV second stage which is powered by one RL-10 engine) from the SLS--instead of the Space Launch System itself--to boost the Orion spacecraft to lunar orbit, and:

This SpaceFlightNow article (see: https://spaceflightnow.com/2019/04/...mmercial-debut/ ), about this week's Falcon Heavy-Arabsat 6A mission, mentions this possibility several paragraphs down. Ironically, much as the minimalist (due to its only 27,000 pound-thrust first stage) Vanguard launch vehicle made possible the highly successful and useful Thor-Able and Thor-Delta launch vehicles, which utilized the Vanguard rocket's two upper stages, the ICPS would remedy one weakness of the Falcon Heavy. Its relatively low-ISP kerolox second stage (powered by one MVAC--Vacuum Merlin--engine) causes the Falcon Heavy's payload mass capability to fall off sharply for higher-energy missions (to and beyond geosynchronous transfer orbits, as well as for lunar and Earth-escape trajectories). Also:

Just as the Titan III, Titan 23, Titan 34D, and Titan IV could use upper stages of various impulse capabilities (the Agena, Transtage, IUS, TOS, Centaur, the 14' wide Centaur-G [later renamed Centaur-T, used on the Titan IV], etc.), depending on the mission requirements, the Falcon Heavy could also utilize different upper stages as per mission requirements. The following section of the article says:
****************************************
Falcon Heavy emerges as backup for NASA’s lunar landing ambitions

As NASA scrambles to respond to the Trump administration’s directive to land astronauts on the moon by 2024 — four years ahead of the previous schedule — the agency in recent weeks has examined backup launch options for crewed missions if the behind-schedule Space Launch System runs into more delays.

In a speech last month at the Marshall Space Flight Center in Alabama, Vice President Mike Pence charged NASA to return astronauts to the lunar surface within five years “by any means necessary.”

The Space Launch System was designed to send NASA’s Orion crew capsule to a planned “Gateway” mini-space station in lunar orbit, where moon landers could dock for sorties to the lunar surface.

But the SLS was supposed to launch in 2017, and officials last month said the heavy-lifter’s first test flight — a mission without astronauts on-board — would likely not happen until 2021.

NASA Administrator Jim Bridenstine ordered a study to see whether commercial rockets could be ready in time to launch the Orion crew capsule on an unpiloted demonstration mission around the moon in 2020, untethering the new spacecraft from further SLS delays.

The study concluded any commercial launch option for the Orion spacecraft would likely take longer to prepare than the Space Launch System, but one intriguing backup to the SLS emerged, Bridenstine said.

[This illustration shows the components of the Space Launch System’s Block 1 configuration, which is the version scheduled to fly on the rocket’s first mission, designated Exploration Mission-1. Credit: NASA] *The article text continues thus*:

“At the end, there is another solution out there,” he said in a NASA town hall meeting April 1.

While the Falcon Heavy falls short of the SLS’s lift capability, Bridenstine said an upper stage called the Interim Cryogenic Propulsion Stage, or ICPS, originally designed for the SLS could be installed on top of the existing Falcon Heavy. The ICPS uses a single Aerojet Rocketdyne RL10 engine and is built by United Launch Alliance, a SpaceX rival.

“Talk about strange bed fellows,” Bridenstine said, referring to the possible marriage of SpaceX and ULA rockets.

The additional stage could have the power to propel the Orion crew capsule and its service module, built in Europe, into lunar orbit. But the scenario would require numerous time-consuming modifications to the Falcon Heavy and its launch pad at the Kennedy Space Center, including additional aerodynamic testing and the placement of new hypergolic and liquid hydrogen fueling equipment at the pad.

“At the end of the day, there is a solution here that could potentially work or the future,” Bridenstine said. “It would require time, it would require cost, and there is risk involved, but guess what? If we’re going to land boots on the moon in 2024, we have time, and we have the ability to accept some risk and make some modifications.

“All of that is on the table,” Bridenstine said. “There is nothing sacred here that is off the table, and that is potential capability that could help us land boots on the moon in 2024.”

In his remarks last month in Alabama, Pence put NASA’s contractors on notice, saying the moon landing objective should not be tied to any single company.

“In order to succeed … we must focus on the mission over the means,” Pence said. You must consider every available option and platform to meet our goals, including industry, government and the entire American space enterprise. Our administration is committed to this goal.”

The launcher is just one piece of the puzzle. NASA must also develop or purchase a human-rated lunar lander that does not exist yet.

While the Falcon Heavy/ICPS launcher could be a viable alternative to the Space Launch System, Bridenstine said the SLS remains the surest way to launch astronauts to the moon by 2024.

Managers at NASA and Boeing, the SLS core stage’s prime contractor, are assessing how the SLS schedule might be accelerated. The SLS first stage engine section, which will house four RS-25 main engines, has been the primary culprit for the rocket’s recent delays.

Teams at the Michoud Assembly Facility in New Orleans, where the SLS core stage is manufactured, have devised a way to assemble the rest of the core stage without the engine section, allowing some work to proceed in parallel, rather than waiting for the aft propulsion module to be ready.

Managers are also considering whether to skip a full-duration eight-and-a-half-minute test firing of the core stage and its four engines at NASA’s Stennis Space Center in Mississippi. The four engines are leftovers from the space shuttle program with extensive flight history, and engineers may decide that a shorter hold-down firing on the launch pad in Florida could satisfy their test requirements.

“The best option to get us to lunar orbit as soon as possible is SLS and an Orion with a European service module,” Bridenstine said. “There’s nothing that beats that capability. Right now, what we’re doing is everything possible to accelerate that.”
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Old 04-13-2019, 06:48 AM
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Joe Wooten Joe Wooten is offline
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We have wasted enough money on the Senate Launch System. It is way past time to cancel it. It never was about getting to the Moon or anywhere else. It was expressly designed as congressional pork
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Old 04-13-2019, 07:12 AM
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ghrocketman ghrocketman is offline
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I don't think we will ever again see another man-rated NASA "owned" launch vehicle.
Way too much congressional PORK and not enough focused initiative to ever get it done.
It will be private sector. NASA has far too much internal and external bureaucracy.
At best they will serve as an administrator of launch facilities and a support role.
The good ol' days of Apollo and that type of focus are long gone. Have been since the last moon landing. After Apollo NASA has become a BAD JOKE when it comes to manned missions.

The only way NASA would become relevant again would be a Constitutional Amendment guaranteeing them a percentage of all federal tax revenue. The funding would have to increase at least 20X, with ZERO outside political oversight.
Any remnant of political control would need to be removed.
All power with the Scientists/Engineers/Astronauts and NONE with bureaucrats.
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Old 04-13-2019, 07:35 AM
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blackshire blackshire is offline
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Quote:
Originally Posted by Joe Wooten
We have wasted enough money on the Senate Launch System. It is way past time to cancel it. It never was about getting to the Moon or anywhere else. It was expressly designed as congressional pork
I agree--it just keeps dragging on and on, keeping Congressional largess (which is taken from all of us) flowing to keep aerospace jobs in those Congressional districts going. (That this happens--as is the case for all NASA programs, except those in which the hardware is built "in-house," as with some scientific satellites and space probes--is not wrong in itself; the wrongness involves keeping those jobs going with no other benefit--hardware, missions, useful data, etc.--accruing therefrom.) Also:

The SLS's Shuttle-based technology is now so old (the design of the RS-25 [formerly the SSME--Space Shuttle Main Engine] dates back half a century now, and the Solid Rocket Boosters' technology also goes back that far, being based on that of the old segmented 10' diameter Titan IIIC Stage 0 solid motors) that it makes no sense to reach back to keep it in use. (It would be like trying to achieve the performance, reliability, and efficiency levels of current jet airliners using 1969 aviation technologies.) While there is nothing wrong with using old technology when it is the best available, this isn't the case for the SLS. For example:

Large solid motors are dirty, dangerous, produce strong vibration, and their sheer weight causes greater wear-and-tear to the Crawler Transporters, the Mobile Launch Platforms, and the rock "road surface" of the crawlerway itself (the Saturn V, for its great size, weighed little more than 200 tons when its tanks were empty, which was how it was transported). The RS-25 engines require much costly inspection even when used just once, because they were made using many parts and many welded joints (today's rocket engines--even reusable ones such as SpaceX's Merlin and Blue Origin's BE-3--are made using greatly advanced production methods, having far fewer parts and welds), and discarding a complex, expensive, and designed-to-be-reusable engine like the RS-25 after just one use is a depth of economic madness that only a government bureaucrat could fail to see as such. Even the RL-10 hydrogen/oxygen upper stage engine, despite its decades of highly reliable service, is slated to be phased out for more modern replacements in other launch vehicles, because it too is largely hand-made, with many parts and welds, which makes it more expensive to procure.
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Old 04-13-2019, 08:45 AM
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blackshire blackshire is offline
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Quote:
Originally Posted by ghrocketman
I don't think we will ever again see another man-rated NASA "owned" launch vehicle.
Way too much congressional PORK and not enough focused initiative to ever get it done.
It will be private sector. NASA has far too much internal and external bureaucracy.
At best they will serve as an administrator of launch facilities and a support role.
The good ol' days of Apollo and that type of focus are long gone. Have been since the last moon landing. After Apollo NASA has become a BAD JOKE when it comes to manned missions.

The only way NASA would become relevant again would be a Constitutional Amendment guaranteeing them a percentage of all federal tax revenue. The funding would have to increase at least 20X, with ZERO outside political oversight.
Any remnant of political control would need to be removed.
All power with the Scientists/Engineers/Astronauts and NONE with bureaucrats.
One possible exception--although the proliferation of capsules makes it rather unlikely (because existing or upcoming ones could be modified for such purposes if needed, but Crew Dragon is already designed with such needs in mind)--could be capsules for deep space exploration missions:

With political/organizational (and even emotional/psychological) realities being what they are, I can see NASA procuring its own crew return capsules for NEO landing missions, Venus and Mars flyby or orbiter missions (such flyby missions can even encounter *both* planets in the same flight, as the 1960s Bellcomm studies showed; with orbiter missions, astronauts could control unmanned rovers or aircraft in real-time, land on the Martian Moons, etc.), and main belt asteroid missions (the inner belt is close enough to not require nuclear-thermal or nuclear-electric propulsion for reasonable voyage durations). But--especially in the case of SpaceX--NASA could just order suitably-outfitted Crew Dragon capsules right off the production line, as its heat shield is already rated for Mars-return re-entry velocities, and:

When NASA was young, before it became a bloated bureaucracy like other federal agencies, they could and did (and took pride in doing so!) achieve great things on the cheap, using relatively few (but highly-talented and enthusiastic) people, and by being willing to take chances--not irrational risks, but calculated risks. Also, they built quite a few spacecraft "in-house"; many of the Explorer scientific satellites were built at the NASA Goddard Space Flight Center (they may still do this, particularly with the smaller Explorer satellites), and JPL built many of the Mariner planetary probes (although Boeing built the Mariner 10 Venus & Mercury probe, on a fixed-price $98 million contract) and also the Voyager spacecraft (which are outer-planet Mariners, just given a new name--so was Cassini, a Mariner Mark II), while TRW, Boeing, RCA, GE, and other contractors built the OGO, OAO, TIROS/ITOS/ESSA, Nimbus, Pioneer, Lunar Orbiter, and other satellites and space probes. Ironically, reducing NASA's budget, but not by too much, *and* in concert with definite, focused, and specified goals, might make them more effective, because--as in their early days--they wouldn't have the money to waste on needless bureaucracy, duplication, endless studies of hardware and projects they *know* will never come to fruition, and so on. For example:

During the Space Shuttle's development (*that* program was a great example of how NOT to do things!), NASA--after the Congressional tide turned against the Shuttle--sought, and got, the U.S. Air Force to join them, presenting a united front that, without which, the program would have been killed. But the USAF, in return for their support, insisted on design changes (a high re-entry crossrange orbiter capable of placing [and returning] large--up to 33,000 pounds--spy satellites in polar orbit, which could return and land at Vandenberg Air Force Base in one orbit if need be). This made the Shuttle much larger than NASA had wanted, and its greater size and weight--as well as the delta-winged orbiter and its greater heat shielding problem--made the vehicle much more expensive, *but*:

Even though they knew that the vehicle they wanted--a simpler and cheaper straight-winged, low-crossrange, "belly-flop re-entry" orbiter (preferably lofted by a reusable winged booster, although cheaper parachute-recovered, simple pressure-fed single and dual reusable boosters also appeared feasible if budget limitations made the winged booster unattainable)--would almost certainly never be built (because it didn't meet the USAF requirements), NASA continued to let study contracts to the aerospace companies--and continued to do "in-house" design work of its own--on straight-winged, low-crossrange orbiters! By that time (the late 1960s - early 1970s), NASA had--due to Apollo--become a larger, "fatter" agency with a much bigger budget, and they had begun to act--and have the outlook--that they do today (ever since Apollo, they've sought to maintain the "standing army" that they acquired for it). They need to get back to the "leaner, meaner, yet more ambitious, and not afraid to take reasonable risks" mindset and culture that they had before about 1964 - 1966, and such cultures are easier to establish, or re-establish, with fewer--but highly-talented and self-motivated--people. as well:

This doesn't mean that studies are worthless or undesirable. If the project being studied is technologically feasible--even if it stretches the state of the art a little (which is a good thing)--and if it is fiscally achievable to implement, then the study is well worth making. Pioneer F, G, and H provide an outstanding example of this opposite, desirable kind of study. The Pioneer 10 and 11 missions were cheap--even by the standards of the early 1970s--and they resulted from a modestly-funded 1960s NASA study for a small (~500 pounds) Jupiter flyby probe that could be lofted by an Atlas-Centaur equipped with a Surveyor solid propellant retrorocket motor as a third stage; both it and the spacecraft would be spin-stabilized. Plus:

The study pointed out that in addition to exploring the asteroid belt, the giant planet itself, and its moons, the probe could utilize Jupiter's powerful gravity as an additional "stage," to either [1] pass behind Jupiter and escape from the Solar System, returning data as it went, [2] pass over a Jovian pole, sling-shooting the spacecraft far above or below (north or south of, respectively) the ecliptic plane, enabling exploration of a whole new region of space, or [3] pass ahead of the planet, which would cancel out the probe's velocity so that it would fall straight into the Sun, returning data on an entire cross-section of the Solar System, from Jupiter into the Sun, during its long descent. This study bore abundant fruit:

Pioneer F became Pioneer 10 after its successful launch, and flew mission type [1], while Pioneer G became Pioneer 11; it flew a modified mission type [2], passing close under Jupiter's south pole and being hurled high above the ecliptic plane, flying by Saturn at about the point where its orbit descended back through the ecliptic. (Due to uncertainty about whether the spacecraft would remain functional long enough to reach Saturn in working order, Pioneer 11's visit to the ringed planet was considered a possible bonus, just as Voyager 2's Uranus--and especially Neptune--flybys were; to everyone's pleasant surprise, they all lasted--both Voyagers are *still* operating!--far longer than even the most optimistic engineers dared to hope.) As for the third spacecraft in this series:

Pioneer H was intended to fly a "full-blown" Jupiter flyby/out-of-ecliptic mission (perhaps higher north than Pioneer 11 went, or maybe over Jupiter's north pole and then down south of the ecliptic), but it was never launched for budgetary reasons (partly due to the Space Shuttle consuming more and more of NASA's budget in the 1970s...)--Pioneer H now hangs in the National Air and Space Museum at 0 ecliptic latitude, serving as a stand-in for Pioneer 10. The ESA/NASA Ulysses spacecraft later flew such an out-of-ecliptic mission. (Ulysses itself was the remnant of the planned two-spacecraft ISPM--International Solar Polar Mission--that would have had two "Jupiter flyby-redirected" spacecraft simultaneously orbiting over both of the Sun's poles to gather "time-matched" data on both hemispheres of our star; the NASA-provided ISPM probe had to be cancelled for budget reasons, largely due to a certain winged spacecraft [space science folks justifiably loathed the Space Shuttle]...) In addition:

I am not surprised that mission type [3] was not attempted with any of the Pioneer outer-planet spacecraft. Only relatively recently, with the Parker Solar Probe launched last October, had the necessary thermal shielding materials and thermal control systems needed for close solar passages been developed sufficiently to make mission planners confident of success (and the $1.5 billion spacecraft's closest approach to the Sun's surface will still be 4.3 million miles away!); with the Pioneer F/G/H probes' 570-pound weight (the Parker Solar Probe weighs 1,510 pounds fueled, and still 1,224 pounds dry), providing a "Sun-diving" Pioneer probe with enough shielding to survive--even just momentarily--contact with, or even just close proximity to, the Sun's photosphere would have been impossible within its mass limit.
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http://www.lulu.com/product/cd/what...of-2%29/6126511
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Last edited by blackshire : 04-13-2019 at 10:22 AM.
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Old 04-14-2019, 09:22 AM
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Joe Wooten Joe Wooten is offline
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Even the RL-10 hydrogen/oxygen upper stage engine, despite its decades of highly reliable service, is slated to be phased out for more modern replacements in other launch vehicles, because it too is largely hand-made, with many parts and welds, which makes it more expensive to procure.

I wonder why Aerojet has not re-engineered the Centaur for easier manufacturing. it is a good motor. The USA used to be really good at rationalizing manufacturing processes.
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Old 04-14-2019, 10:03 AM
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Quote:
Originally Posted by Joe Wooten
Even the RL-10 hydrogen/oxygen upper stage engine, despite its decades of highly reliable service, is slated to be phased out for more modern replacements in other launch vehicles, because it too is largely hand-made, with many parts and welds, which makes it more expensive to procure.

I wonder why Aerojet has not re-engineered the Centaur for easier manufacturing. it is a good motor. The USA used to be really good at rationalizing manufacturing processes.


Aerojet Rocketdyne is, in fact, putting a lot of effort into simplifying RL10 manufacturing. (You are correct - the original versions are very much hand made!). The improved versions are on the way, and should fly for the first time next year on Atlas V. An improved engine on Delta IV should follow in 2021. Versions with even more improvements should hit the scene in roughly 3-4 years - including much higher performance!
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