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I think what we will see out of Spacex is half a dozen to a dozen-or-so reflights per booster. Not tens-of-thousands like an airplane. This is due in part to the use of aluminum-lithium alloys, which are not yet mature enough to predict long fatigue life for tankage subjected to extreme loads returning from orbital first stage speeds. It is also due in part to liquid engine characteristics.
The shortest-life component in most liquid engines has been the turbopump assembly. It is also the most expensive component. More than a few flights per turbopump assembly has yet to be demonstrated. Maybe it can, and maybe it cannot. We'll see. Shuttle couldn't do it.
Right up there as a close second for limiting factor is coking of kerosene in the regenerative cooling passages of kerosene-LOX engines. Coking is cooked carbon deposits inside the passages, and it is very hard to remove, much like the carbon deposits that are so hard to remove from automotive engines at overhaul time.
I do not know which of these will limit Spacex's reuse of first stages, or Blue Origin's, for that matter. Use of methane fuel instead of kerosene may reduce the coking, or it may not. We'll see. New technology, and all that that status implies. Don't hold your breath.
But I wish them well with it (methane instead of kerosene). We need something new.
The oldest way around the turbopump life problem is pressure-feed propellants. It works, but it is heavy, as heavy as the case of a solid, if not heavier. I would only do that in engine and propellant systems that are small mass compared to the airframe mass.
The other way is something XCOR has done on one form or another for some years now: piston-pump feed. They say it only looks feasible in smaller systems, like those of their Lynx rocket engines. But in those smaller systems, it is a real winner.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Trump's comments regarding NASA reauthorization act, Hubble Space telescope, and the James Webb telescope.
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How to speak from the heart and not screw up the teleprompter
Biden to unveil first photo from James Webb Space Telescope
https://www.nbcnews.com/science/space/f … ecommended
President Joe Biden will unveil the much-anticipated first full-color image from NASA's James Webb Space Telescope on Monday, agency officials confirmed.
The agency and its partners, the European Space Agency and the Canadian Space Agency, are set to release a separate batch of full-color images from the Webb telescope on Tuesday, but Biden, Vice President Kamala Harris and the public will get a sneak peek a day early.
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In May year 2069 there will be a Lunar Eclipse, how will it be celebrated, marked and remembered?
There is a vision to walk once again on the Moon and to orbit the Moon with a space station. Many thought people would soon be on Mars after NASA landed on the Moon.
while it was an achievement for mankind nobody can take it from the USA the books of History will always remember 'First on the Moon'....there are more players than the USA and Russia-Soviets, the Russians have moved backward maybe and there is of course a possibility China or somebody in the future might look at Mars and Europe or one day, some global space Mega-Corp might put Cyborgs on Ceres or Mercury or Enceladus or Callisto.
for now Chinese are not racing and the US Admins don't show the same urgency as previous Presidents.
and an economy people want to talk about.
'While NASA's 2024 budget proposal represents a welcome increase for the space program, much of it is eaten up by recent inflation.'
https://twitter.com/exploreplanets/stat … 2476638208
In defense of space colonies and mining the high frontier
https://thehill.com/opinion/technology/ … -frontier/
When President John F. Kennedy gave his famous speech at Rice University defending the Apollo moon race in 1962, he invoked a historic figure who was famous for founding one of the first European colonies in North America. “William Bradford, speaking in 1630 of the founding of the Plymouth Bay Colony, said that all great and honorable actions are accompanied with great difficulties, and both must be enterprised and overcome with answerable courage,” Kennedy remarked.
The sentiment is evocative of a simpler time in America, when most people regarded the settling of the New World as a heroic process, leading to the founding of new nations, not the least of which was the United States. Naturally, JFK could view the exploration of space in much the same way as the exploration and settlement of the Americas was regarded in his time.
Over 60 years later, attitudes toward America’s past and her future have changed. Many historians regard the settlement of the Americas as an unrelenting atrocity against the indigenous people who resided there before the arrival of the Europeans. The truth about whether the settling of the Americas was heroic or an atrocity is now a matter for debate, although some validity exists for both points of view.
Unfortunately, the more caustic view of America’s past has tainted some opinions about America’s future. According to The Guardian, at least one scientist, astrobiologist and planetary scientist Pamela Conrad, would like any thought of founding colonies in space and exploiting the resources of celestial bodies to be dispensed with entirely. Humans, if they venture into space at all, should do so for only the “pure” reasons of science and exploration.
Conrad, of the Carnegie Institution of Science, recently spoke on a panel on the ethics of space exploration at the American Association for the Advancement of Science (AAAS) meeting in Washington, D.C. She stated, “that rather than setting out to own or take resources from space, humans should endeavor to be ‘gentle explorers.’”
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I had never intended this thread to become "political," but due to the involvement of government in space travel, vis a vis NASA, it was unpreventable.
That said, I believe now that SpaceX has become the world leader in space exploration technology, and NASA is now "along for the ride." Other companies such as Axiom Space will now be "renting " their space suits to NASA.
Philanthropist Jared Isaacman is now paying his own way to space to do innovative research that NASA cannot find funding to accomplish, and will probably be the first pilot of the Starship.
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United States and South Korea agree to enhance space cooperation
https://spacenews.com/united-states-and … operation/
Marianne Williamson starts 2024 challenge against Biden
https://scrippsnews.com/stories/mariann … nst-biden/
Author and self-help expert
Robert F. Kennedy Jr is running, he is son of the murdered 1968 Presidential candidate Bobby Kennedy and nephew of President John F. Kennedy, I don't know if he would be Pro-Space like his Uncle. He questions big corporations and Pharma companies, some in news media call him a 'conspiracy theorist'.
He declared he is running nad candidate Robert Kennedy Jr. challenged Biden to debate as many Americans have 'major' concerns about president's age.
Victor Davis Hanson: Democrats Will Not Allow RFK Jr. On The Debate Stage With Biden, It Would Be A Disaster
https://www.realclearpolitics.com/video … aster.html
Trump's camp is trying to force Ron DeSantis to resign and formally declare a 2024 run, accusing the governor of 'taxpayer-funded globetrotting'
https://www.businessinsider.com/donald- … ing-2023-4
Biden’s Democratic Challengers Complain About Lack of Planned Debates, ‘Rigged’ Primary
https://www.nysun.com/article/bidens-de … ed-primary
Marianne Williamson and Robert F. Kennedy Jr. are griping that they won’t get the chance to debate the president
Vice President Harris’ visit with South Korean President Yoon some complain a photo op ?
https://www.nasa.gov/feature/goddard/20 … sa-goddard
South Korea's Yoon hails US ties at joint meeting of Congress
https://www.france24.com/en/live-news/2 … f-congress
Last edited by Mars_B4_Moon (2023-04-29 11:38:34)
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