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41

Engineering / Re: Interesting stuff about SpaceX Starship (hate the name)

« Last post by Nemesis on July 25, 2024, 07:56:02 pm »

Starliner now has no firm return date.  They are extending the mission to AT LEAST 45 days and may well go beyond that.  I've seen reports that the next Crew Dragon in August can't dock with the ISS unless one of the craft already there departs. 

NASA and Boeing are trying to act like this is not serious but extending a 10 day (MAX) mission long enough to interfere with the normal crew rotation seems pretty serious to me. 

Could it be that they want the next Crew Dragon to take equipment to allow carrying the Starliner crew down in the Dragon already there (making it carry 6 not 4)?  In which case presumably Starliner would return uncrewed (if it makes it).  If this happens it may be the end of Starliner.

Really not looking good.

Finally some more info:  Link to article

And the testing may have helped give engineers a better understanding of the issue’s “root cause”: Heat building up inside the thrusters may be causing Teflon seals to bulge, restricting the flow of propellant.

The findings also prompted Boeing and NASA to abandon plans to allow the astronauts to manually fly the Starliner spacecraft on the way home, as they did briefly during the trip to the ISS. “Some of the manual maneuvering put some extra stress on the thrusters,” said Steve Stich, NASA’s Commercial crew program manager.

Still, officials did not definitively say Thursday that the Starliner spacecraft that carried veteran NASA astronauts Butch Wilmore and Suni Williams to the space station would be the same vehicle that brought the astronauts back home.

“There is a lot of good reasons to complete this mission and bring Butch and Suni home on Starliner,” Stich said after noting that NASA does have contingency options if Starliner is not approved to bring the astronauts home.

The Helium leak source:

Analysis of components on the ground — specifically, a version of the Starliner’s service module that’s been sitting in White Sands, New Mexico for three years — showed that the helium leaks may be a result of seals that have become degraded because of exposure to propellant vapor, according to Nappi.

No commitment as to how they will bring them home.

42

Announcements / Re: HAPPY JULY 4th!!!

« Last post by Panzergranate on July 22, 2024, 09:01:08 pm »

I spent the 4th of July in Poole General Hospital with a severe gall bladder infection, gall stones and jaundice. I had half of my gallbladder removed and spent 14 days in a hospital bed. I missed voting in the UK general election, something I always dutifully participate in, out of reverence to all those people who fought throughout British history for my right to have a vote.

Fortunately, Britain has a national health service and not a profiteering health industry, so my treatment in hospital cost me nothing, because I'd already contributed towards it all with my taxes throughout my life.

43

Announcements / Re: HAPPY JULY 4th!!!

« Last post by Starfox1701 on July 15, 2024, 04:16:33 pm »

thank you

44

Engineering / Re: Interesting stuff about SpaceX Starship (hate the name)

« Last post by Nemesis on July 09, 2024, 08:29:11 pm »

Ariane 6 has had a partially successful first launch. The issues were with the 2nd stage and its failed reignition resulting in not all the payloads being put in orbit or on their return to Earth trajectory in a couple of cases.

Not great but for a first flight not a total failure. 

Update: 

The 2nd stage was to ignite three times the first two were successful and all the satellites were put in their correct orbits.  The 3rd ignition was to deorbit the craft and place 2 more "probes" on paths which would result in them landing by parachute.  The 2nd stage will now have to wait till the orbit naturally ends could be years or even decades so the "probes" are effectively lost as their electronics won't last that long. 

So more successful than my initial thinking.  If they were only placing satellites in one orbit plus the "probes" this would likely have been a total success.

A good but not great first flight.

45

Announcements / HAPPY JULY 4th!!!

« Last post by FA Frey XC on July 04, 2024, 08:58:43 pm »

We salute the USA's Independance day!

Regards,

~The D.net Team

46

Engineering / Re: Interesting stuff about SpaceX Starship (hate the name)

« Last post by Nemesis on July 04, 2024, 09:21:20 am »

Starliner now has no firm return date.  They are extending the mission to AT LEAST 45 days and may well go beyond that.  I've seen reports that the next Crew Dragon in August can't dock with the ISS unless one of the craft already there departs. 

NASA and Boeing are trying to act like this is not serious but extending a 10 day (MAX) mission long enough to interfere with the normal crew rotation seems pretty serious to me. 

Could it be that they want the next Crew Dragon to take equipment to allow carrying the Starliner crew down in the Dragon already there (making it carry 6 not 4)?  In which case presumably Starliner would return uncrewed (if it makes it).  If this happens it may be the end of Starliner.

Really not looking good.

47

Engineering / Re: Interesting stuff about SpaceX Starship (hate the name)

« Last post by Nemesis on June 28, 2024, 06:34:07 pm »

Dream Chaser (space cargo plane) to be launched on Vulcan in September now delayed to December.

Based on prior delays to December of different missions I consider the December launch unlikely.  They seem to place them at year end till they find out what is likely to happen.  ULA currently has a July launch, a September launch and FIVE December launches with 3 of those being Vulcan.  Seems highly unlikely to me. 

48

Engineering / Re: Interesting stuff about SpaceX Starship (hate the name)

« Last post by Nemesis on June 26, 2024, 05:28:40 am »

The filter clogging on the booster is now explained.  How they plan to stop it recurring is not explained.

They maintain tank pressurization with partially burned propellant from the propellant pumping system (burning the propellant powers the pumps).  The combustion results in CO2 and water.  It is water ice that is causing the filter clogging.  Water obviously freezes at the temperatures of LOX and liquid methane.  Maybe they will have to change things so the combustion products don't do the pressurization but the actual material being pumped does?  Or some other way to keep ice from the filters.

49

Engineering / Re: Interesting stuff about SpaceX Starship (hate the name)

« Last post by Nemesis on June 25, 2024, 09:17:13 pm »

Just like a lot of things with Super Heavy this can be tried first on Starship and is much easier with the reduced mass.  Almost all components for SH are common with Starship, now the Earth landing is shared too.  This allows Starship to do almost all the prototype level work for SH.

I've been reviewing some old posts.  I got this one wrong.  I didn't consider the added difficulty of returning from orbit for the catch.  So Super Heavy gets caught first. 

Ooops. 

50

Engineering / Re: Interesting stuff about SpaceX Starship (hate the name)

« Last post by Nemesis on June 25, 2024, 01:29:34 pm »

It appears a test tank (14.1) that was made for testing the strength of the "pins" the booster lands on may actually be dropped onto the mechazilla arms by a crane.  This would also test the catching arms themselves and perhaps its ability to reposition a booster along the length of the arms and to rotate it for correct orientation (though this may already have been tested with a full booster, I don't recall it being done but might have missed it).

SpaceX has applied to the FCC to use certain frequencies for catch attempts on IFT5 and IFT6 with IFT7 later using revised frequencies.  Start date for use of the frequencies (presumably for testing not a flight/landing) is July 17th.  Nothing to indicate whether this would include the test tank drop mentioned above.

Ariane 6 over due by 4 years has had a successful wet dress rehearsal so a flight may be relatively soon (within 6? months perhaps).  So the EU may soon be back to launching their own rockets.