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posted by mrpg on Tuesday May 22 2018, @02:46AM   Printer-friendly
from the thunderbirds-are-go dept.

SpaceX's controversial rocket fueling procedure appears 'viable,' says NASA safety advisory panel

A NASA safety advisory group weighed in Thursday on SpaceX's highly scrutinized proposal to load rocket propellants while astronauts are aboard, saying it appears to be a "viable option."

Several members of the Aerospace Safety Advisory Panel said that as long as potential hazards can be controlled, loading crew before fueling is finished could be acceptable.

"My sense is that, assuming there are adequate, verifiable controls identified and implemented for the credible hazard causes, and those which could potentially result in an emergency situation ... it appears load-and-go is a viable option for the program to consider," panel member Capt. Brent Jett Jr. (Ret.) said during Thursday's meeting.

SpaceX and Boeing Co. each have NASA contracts to develop separate crew capsules to transport astronauts to the International Space Station. Both SpaceX and Boeing are scheduled to conduct uncrewed flight tests of their vehicles in August, with crewed flight tests set for several months later.

A Falcon 9 blew up during propellant loading in 2016.

Previously: NASA Advisory Committee Skeptical of SpaceX Manned Refueling Plan

Related: SpaceX Identifies Cause of September Explosion
Problems With SpaceX Falcon 9 Design Could Delay Manned Missions


Original Submission

Related Stories

NASA Advisory Committee Skeptical of SpaceX Manned Refueling Plan 20 comments

Experts advising NASA are not impressed with SpaceX's plan to fuel rockets while astronauts are aboard, particularly in the wake of the September 1st explosion:

"This is a hazardous operation," Space Station Advisory Committee Chairman Thomas Stafford, a former NASA astronaut and retired Air Force general, said during a conference call on Monday. Stafford said the group's concerns were heightened after an explosion of an unmanned SpaceX rocket while it was being fueled on Sept. 1. Causes of that explosion remain under investigation.

Members of the eight-member group, including veterans of NASA's Gemini, Apollo and space shuttle programs, noted that all previous rockets carrying people into space were fueled before astronauts got to the launch pad. "Everybody there, and particularly the people who had experience over the years, said nobody is ever near the pad when they fuel a booster," Stafford said, referring to an earlier briefing the group had about SpaceX's proposed fueling procedure.

SpaceX needs NASA approval of its launch system before it can put astronauts into space. NASA said on Tuesday it was "continuing its evaluation of the SpaceX concept for fueling the Falcon 9 for commercial crew launches. The results of the company's Sept. 1 mishap investigation will be incorporated into NASA's evaluation."

SpaceX posted updates about the explosion on Oct. 28. The helium loading system appears to have caused the problem. SpaceX wants to resume launches before the end of the year.


Original Submission

SpaceX Identifies Cause of September Explosion 10 comments

Elon Musk appeared on CNBC and offered a definitive explanation for his company's recent launch explosion:

SpaceX CEO Elon Musk says that his company has finally gotten to the bottom of the September 1st Falcon 9 explosion — claiming it was the "toughest puzzle" they've ever had to solve. And now that the problem is known, he expects SpaceX to return to flight in mid-December.

Speaking on CNBC yesterday, Musk said "it basically involves liquid helium, advanced carbon fiber composites, and solid oxygen. Oxygen so cold that it actually enters solid phase." So what does that mean exactly? Musk gave some hints a little while ago during a speech he gave to the National Reconnaissance Office. According to a transcript received by Space News, he argued that the supercooled liquid oxygen that SpaceX uses as propellant actually became so cold that it turned into a solid. And that's not supposed to happen.

This solid oxygen may have had a bad reaction with another piece of hardware — one of the vehicle's liquid helium pressure vessels. Three of these vessels sit inside the upper oxygen tank that holds the supercooled liquid oxygen propellant. They're responsible for filling and pressurizing the empty space that's left when the propellant leaves the tank. The vessels are also over wrapped with a carbon fiber composite material. The solid oxygen that formed could have ignited with the carbon, causing the explosion that destroyed the rocket.

Musk called the issue one that had "never been encountered before in the history of rocketry." One of SpaceX's customers, Inmarsat, may find an alternative for one of its upcoming satellite launches. SpaceX launches could resume mid-December.

For comparison's sake, at standard pressure:


Original Submission

Problems With SpaceX Falcon 9 Design Could Delay Manned Missions 16 comments

SpaceX is no stranger to delays. The private space firm headed by Elon Musk has pushed back is launch schedule several times in the last few years after rockets have been lost. Now, the Government Accountability Office (GAO) says there may be an issue with the Falcon 9 rocket that delays the expected launch of the first manned mission in 2018.

The report from the GAO (just a preliminary release for now) cites issues with the turboblades used in Falcon 9 rockets. These are the components that move fuel from the tanks to engines. The blades apparently have a tendency to develop cracks, which could cause catastrophic failure if they develop or worsen during a launch.

According to NASA acting administrator Robert Lightfoot (who also has an amazing name) says the agency and SpaceX have been aware of the issue for months (or possibly years). NASA expressed concern to SpaceX that the turboblade cracks presented too great a risk to launch manned missions. Cracks have been found in the turboblades as recently as September 2016.

SpaceX says it has been conducting extensive testing on the Falcon 9 rocket and believes it to be safe. It has made changes to the design of the turboblades in an effort to mitigate the cracking issues. Although, the company may still undertake a full redesign of the blades depending on the upcoming GAO report. If that happens, the manned launch will almost certainly be delayed.

Source:

https://www.extremetech.com/extreme/243883-problems-falcon-9-design-delay-manned-missions


Original Submission

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  • (Score: 3, Interesting) by tftp on Tuesday May 22 2018, @06:36AM (3 children)

    by tftp (806) on Tuesday May 22 2018, @06:36AM (#682548) Homepage
    Should be OK ... as long as the payload with humans is equipped with a launch escape system [wikipedia.org].
    • (Score: 2) by bob_super on Tuesday May 22 2018, @04:29PM (1 child)

      by bob_super (1357) on Tuesday May 22 2018, @04:29PM (#682695)

      Pretty much my take on it.
      Is it really safer to go to a pad that has a giant bomb on it, take the elevator, climb aboard, then finally strap in and close the hatch ?
      I would go for strapping in first, check the escape rockets are on, then load the bomb, even if that's a long boring process.

      Sure, the odds of kaboom are higher during loading, but even if they are 50x higher than when the rocket is just sitting there loaded while I get on it, the odds of survival in the latter case are much much lower.

      Anne Frankly, if I ain't going to space today because of a giant boom, riding the escape system is the thrill of a lifetime (even if it breaks more ribs than a real takeoff), when looking at the rocket go boom from a safe distance is just a terrible -while awesome- disappointment.

      • (Score: 1, Insightful) by Anonymous Coward on Tuesday May 22 2018, @05:47PM

        by Anonymous Coward on Tuesday May 22 2018, @05:47PM (#682729)

        In traditional case you approach the fully loaded bomb wearing just a light spacesuit. If anything happens while you are riding the elevator and packing in, you burn up to fine ashes. Consider that the rocket is venting fuel components most of the time.

        In this case you are walking up to an inert metal tube. Once you are in, the descent capsule can withstand some serious fire on its own, because that's how it lands. And the rocket on top will fire soon enough. So it might be that the crew is even safer this way, being always protected.

    • (Score: 2) by darkfeline on Wednesday May 23 2018, @06:06PM

      by darkfeline (1030) on Wednesday May 23 2018, @06:06PM (#683186) Homepage

      Isn't the explosion the launch escape system?

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  • (Score: 0) by Anonymous Coward on Tuesday May 22 2018, @12:27PM

    by Anonymous Coward on Tuesday May 22 2018, @12:27PM (#682613)

    The article links to a news article that reports on the Nasa report.

    For now, human space flight involves a crew strapping themselves to a really big firework after Wiley Coyote.
    'Safety' advisory panels can dress it up, but the nature of the game is always going to involve balance between extraordinary risk and an extraordinary ride.
    The question is how to pick a smart balance.
    Using solids in the shuttle was an interesting balance point way outside the comfort zone of many at the time.
    Load and go may be similar.

    It seems to me that the best argument for load and go is that the crew is never helpless whenever the thing has the fuel to make a big kaboom.
    The argument against is that the fueling process is the second most likely thing to ignite the kaboom.

    I'd like to actually understand what SpaceX did to the He tank and fueling process to lower the unscheduled disassembly odds.

    So, anybody know where the Nasa report is?

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