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#901 2021-02-02 11:29:11

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,384

Re: Starship is Go...

SpaceNut: The FAA is under the jurisdiction of the U.S. Department of Commerce, a Cabinet level position. Biden is NOT a fan of Elon Musk, and the "10 % for the big guy" may still pervade his thinking. The FAA IS very political behind the facade of do-gooder-ism.
I currently hold a Private Pilot Certificate, and am still campaigning to regain my flight medical after a heart attack 3 years ago. It's not easy to deal with the bureaucracy of the FAA.
Biden has a very political cabinet, which is responsive to his wishes.

Last edited by Oldfart1939 (2021-02-02 11:45:19)

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#902 2021-02-02 13:53:30

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,882

Re: Starship is Go...

So much for politics of Democrats being the issue.....
SpaceX SN9 could fly today from South Texas, as FAA approves launchBB1dkanP.img?h=416&w=799&m=6&q=60&u=t&o=f&l=f

“Their rules are meant for a handful of expendable launches per year from a few government facilities. Under those rules, humanity will never get to Mars.”

The musk complaint is due to caution of flights being so dangerous for a new vehicle design which has not been prove with any of the features that its trying to bring into being.

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#904 2021-02-02 19:04:51

louis
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From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Starship is Go...


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#905 2021-02-02 20:14:36

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,882

Re: Starship is Go...

It does not look like the closeup of the flap was in the correct position before it flashed to the landing....
You can see something flying over the sn10 ship thats on the other launch pad...

Starship SN9 loses a Raptor during flipEtQSpStWYAASANN-1170x780.jpg

Flight video

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#906 2021-02-02 21:12:11

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 5,459
Website

Re: Starship is Go...

There was some sort of unintended fire going on, in the engine bay,  all during the ascent.  While the engine bay video coverage was interrupted,  the fire was not:  it was still there in the last seconds before impact. 

It takes two engines to thrust vector the craft to tail first for landing.  We saw that with SN-8. It also takes two engines to achieve enough thrust to decelerate the vehicle for landing.  With SN-9,  they got one engine ignited,  but the second failed to ignite. 

My guess is that the persistent fire has something to do with the failure of the second engine to ignite.  That sort of fire damages equipment. You can clearly see in the images right before it crashed that only one engine was firing,  and that there was a reddish fuel fire going on not far from that one running engine in the engine bay. 

At least we did not see the green copper-burning of oxygen-rich operation due to low fuel pressure,  which is what happened on SN-8.  That part of the plumbing issues seems resolved.  Now the methane leaks that seem to have caused this crash need attention.

This is not only like the early rocket work of the 1950's,  it is like most of the experimental aircraft test work of the 50's and 60's,  maybe even the 70's.  Lots of those vehicles crashed.  The issues Spacex faces are as much about how to fly supersonic vehicles reliably,  as they are about making a rocket work.

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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#907 2021-02-02 23:23:13

Oldfart1939
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Registered: 2016-11-26
Posts: 2,384

Re: Starship is Go...

"Space is hard!" quoted by thousands of engineers...

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#908 2021-02-02 23:24:43

Oldfart1939
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Registered: 2016-11-26
Posts: 2,384

Re: Starship is Go...

SpaceX is on a very fast track with the Starship design, and this is all part of the learning curve. Not the last RUDs that we'll undoubtedly see.

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#909 2021-02-03 17:33:28

GW Johnson
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From: McGregor, Texas USA
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Posts: 5,459
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Re: Starship is Go...

I do take considerable issue with this particular statement of Louis's.  In point of fact,  it is bullshit,  and there is no other accurate way to describe it.  Quote:

"Exactly. Far Left Democrats have always hated the space programme. They are calling ths shots in the Democratic Party now. This will only get worse, especially once Kamala Harris becomes President, in about 8 months' time."

The US space program as we know it,  and as we have known it for over 6 decades,  got started in 1958 with the formation of NASA from the older NACA,  under Republican president Dwight Eisenhower.  Before that,  there was an Army program and a competing Navy program to develop the rockets and the satellite hardware to launch an orbiting satellite.  Eisenhower reportedly let the Russians orbit Sputnik first in order to get them to de facto agree to the open skies principle,  although there are some who dispute that.  Myself,  that's what I think Ike did,  because he was anything but an incompetent person.  I do remember him.  Harry Truman was president when I was born.

It was the next president,  Democrat John Kennedy,  who in 1961 or 1962 gave NASA the goal of flying to the moon before the end of the 1960's.  And THAT is the genesis of the US space program as we have known it.  Kennedy was actually just looking for something we could use to outcompete the Russians,  it was his vice president Lyndon Johnson who was the real space advocate.  With LBJ president and re-elected after Kennedy's assassination,  we had several years of a president who was a strong advocate of an ambitious space program. 

And that man was a Democrat,  Louis.  I was there.  I witnessed it.  Whoever told you otherwise lied to you.

LBJ left office January 1969,  when Republican Richard Nixon became president.  Nixon was no space advocate,  and wanted to reverse or destroy all that he could of the Kennedy-Johnson legacy.  It was Nixon's executive order in 1972 that stopped the Apollo program at Apollo 17,  although we had hardware and trained crews to support missions through Apollo 22 (already paid for and built).  This order restricted human spaceflight to low Earth obit,  which killed the Mars mission,  at the time scheduled for 1987.  I know,  I was trying to become an astronaut to go to Mars,  when I was young.  It also killed the nuclear thermal rocket program,  because "if we aren't going to Mars,  who needs the rocket?".

Nixon resigned with vice president Jerry Ford taking over for him.  Those were the space shuttle years,  when it shrank from a real reusable two-stage airplane to the cluster that we all know.  (Nixon's original vice president Spiro Agnew resigned because of a corruption scandal.)

Democrat Jimmy Carter followed Nixon/Ford,  but was not much of a space advocate.  He continued the shuttle development thing. 

Republican Ronald Reagan followed Carter,  and saw the shuttle finally fly on his watch.  He wanted the X-30 Orient Express as a follow-on to shuttle,  but it was based on the technical marketing lie that scramjet has sufficient frontal thrust density at 100-150 thousand feet to climb.  It does not.  It never did,  and it never will.  So that didn't go anywhere.  One thing he did do was start the space station program.

Republican George H. W. Bush followed Reagan,  and continued the space station program,  and saw its construction begin on his watch. 

Democrat Bill Clinton followed,  and continued the space station construction. 

Republican George W. Bush followed,  and wanted to go back to moon,  but got all caught up fighting two mideast wars,  one of which was started on what we now know to be lies. 

Democrat Barack Obama followed,  and wasn't too much of a space advocate.  He did continue the NASA moon rocket,  though.

Republican (? because when younger he was a Democrat) Donald Trump followed,  and he was no space advocate either.  He continued the NASA moon rocket (now made obsolete by the likes of Spacex),  and allowed the halo orbit lunar space station program.

Now we have Democrat Joe Biden,  who is not known to me to be that much of a space advocate.  We'll see what he does.  Meanwhile the private sector is doing more than the government,  particularly the "new space" guys.

Whether a president is a space advocate or not seems to have a lot more to do with his personal preferences,  and pretty much NOTHING to do with his political party,  Louis!

GW

Last edited by GW Johnson (2021-02-03 17:54:09)


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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#910 2021-02-04 16:27:59

louis
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From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Starship is Go...

I didn't want to make this political. It was simply a statement of observable fact that Far Left Democrats have always been anti-space exploration,  considering it as a diversion from the issues of racism. poverty and inequality etc on Earth. I remember dimly hearing activists interviewed back in the lates 60s in Chicago. Obama was a leftist political organiser in Chicago. There's no doubt he would have imbibed anti-space exploration rhetoric in his 20s and his Presidency demonstrated his lack of support for space exploration. I wouldn't Trump was anti space exploration. I would agree he didn't accord it high priority against the need to revitalise the US economy. I don't think he was a fan of NASA but he did nothing to slow down Space X.

We will see how events unfold but I think Musk could face obstructionism because the Left in the Democratic Party are gaining influence as time goes by.



GW Johnson wrote:

I do take considerable issue with this particular statement of Louis's.  In point of fact,  it is bullshit,  and there is no other accurate way to describe it.  Quote:

"Exactly. Far Left Democrats have always hated the space programme. They are calling ths shots in the Democratic Party now. This will only get worse, especially once Kamala Harris becomes President, in about 8 months' time."

The US space program as we know it,  and as we have known it for over 6 decades,  got started in 1958 with the formation of NASA from the older NACA,  under Republican president Dwight Eisenhower.  Before that,  there was an Army program and a competing Navy program to develop the rockets and the satellite hardware to launch an orbiting satellite.  Eisenhower reportedly let the Russians orbit Sputnik first in order to get them to de facto agree to the open skies principle,  although there are some who dispute that.  Myself,  that's what I think Ike did,  because he was anything but an incompetent person.  I do remember him.  Harry Truman was president when I was born.

It was the next president,  Democrat John Kennedy,  who in 1961 or 1962 gave NASA the goal of flying to the moon before the end of the 1960's.  And THAT is the genesis of the US space program as we have known it.  Kennedy was actually just looking for something we could use to outcompete the Russians,  it was his vice president Lyndon Johnson who was the real space advocate.  With LBJ president and re-elected after Kennedy's assassination,  we had several years of a president who was a strong advocate of an ambitious space program. 

And that man was a Democrat,  Louis.  I was there.  I witnessed it.  Whoever told you otherwise lied to you.

LBJ left office January 1969,  when Republican Richard Nixon became president.  Nixon was no space advocate,  and wanted to reverse or destroy all that he could of the Kennedy-Johnson legacy.  It was Nixon's executive order in 1972 that stopped the Apollo program at Apollo 17,  although we had hardware and trained crews to support missions through Apollo 22 (already paid for and built).  This order restricted human spaceflight to low Earth obit,  which killed the Mars mission,  at the time scheduled for 1987.  I know,  I was trying to become an astronaut to go to Mars,  when I was young.  It also killed the nuclear thermal rocket program,  because "if we aren't going to Mars,  who needs the rocket?".

Nixon resigned with vice president Jerry Ford taking over for him.  Those were the space shuttle years,  when it shrank from a real reusable two-stage airplane to the cluster that we all know.  (Nixon's original vice president Spiro Agnew resigned because of a corruption scandal.)

Democrat Jimmy Carter followed Nixon/Ford,  but was not much of a space advocate.  He continued the shuttle development thing. 

Republican Ronald Reagan followed Carter,  and saw the shuttle finally fly on his watch.  He wanted the X-30 Orient Express as a follow-on to shuttle,  but it was based on the technical marketing lie that scramjet has sufficient frontal thrust density at 100-150 thousand feet to climb.  It does not.  It never did,  and it never will.  So that didn't go anywhere.  One thing he did do was start the space station program.

Republican George H. W. Bush followed Reagan,  and continued the space station program,  and saw its construction begin on his watch. 

Democrat Bill Clinton followed,  and continued the space station construction. 

Republican George W. Bush followed,  and wanted to go back to moon,  but got all caught up fighting two mideast wars,  one of which was started on what we now know to be lies. 

Democrat Barack Obama followed,  and wasn't too much of a space advocate.  He did continue the NASA moon rocket,  though.

Republican (? because when younger he was a Democrat) Donald Trump followed,  and he was no space advocate either.  He continued the NASA moon rocket (now made obsolete by the likes of Spacex),  and allowed the halo orbit lunar space station program.

Now we have Democrat Joe Biden,  who is not known to me to be that much of a space advocate.  We'll see what he does.  Meanwhile the private sector is doing more than the government,  particularly the "new space" guys.

Whether a president is a space advocate or not seems to have a lot more to do with his personal preferences,  and pretty much NOTHING to do with his political party,  Louis!

GW


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#911 2021-02-05 16:43:09

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 5,459
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Re: Starship is Go...

Louis:

I was trying to de-politicize it.  Besides the far left Democrats (not all Democrats are far left,  by the way),  there are a lot of Republicans who are not space advocates,  and they don't necessarily have to be far right. 

What I gave you was a list of presidents,  evaluated as to their space advocacy.  Actually,  congresses would be more important than any particular president.  Of the presidents I listed for you,  only one was a true space advocate (LBJ),  one was sort-of an advocate (JFK),  and the rest ranged from rather poor advocates to not advocates at all. 

And it crossed party lines.  Which is why I said it is more about the person than his party.

I was too young to remember much about Truman.  And too young to remember much about Ike until his second term.  But that time was before there was any serious thoughts about going into space. 

The Army and Navy programs started about 1955-ish.  The Navy program was "official" (Vanguard).  The Army program was quite unofficial,  until Vanguard failed.  That was the Jupiter-C version of von Braun's Redstone that pushed Explorer 1 to orbit. That stuff I remember.

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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#912 2021-02-05 20:15:00

SpaceNut
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Posts: 28,882

Re: Starship is Go...

Back investigation FAA Investigates Explosive Landing of SpaceX's Mars Starship Prototype

Have not found any close up engine performance like before on sn8 where the camera's clearly show the engine shutting down to be very violent and I would suspect that the engines are getting damage during that sequence as to while they are failing later when trying to reignite them for the full throttle landing.

Although this was an un-crewed test flight, the investigation will identify the root cause of today's mishap and possible opportunities to further enhance safety as the program develops.

Follow up article contained insn9 for what happened with sn8

As always expectations had to be calibrated, with this being just the second high altitude flight of a prototype Starship, the one issue with SN8’s flight – the loss of pressure in the CH4 Header Tank during the landing burn – has since been mitigated ahead of SN9’s attempt.

I think GW said that

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#913 2021-02-06 10:32:31

Oldfart1939
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Registered: 2016-11-26
Posts: 2,384

Re: Starship is Go...

GW-
Serious PUBLIC interest in space was initiated by a series of articles in the now-defunct Collier's magazine. This is where the public got their first glimpse of the genius of von Braun. This was about 1952 through 1954. I was a Aerospace Engineering Freshman at University of Colorado in 1957 when Vanguard had it's series of failures and Sputnik was launched by the Soviet Union. Eisenhower was actually an advocate of space, but was reluctant to use then existing military hardware to do the necessary launches. At the time, Redstone was available, and also Atlas I. Because of competition between the Army and Air Force, von Braun was prohibited from using the Jupiter rocket as a launch vehicle first stage as early as 1955. So...our entry into space was actually delayed by Politics. We had the ability to beat the Soviets into Space, but not the Political Will. Once Sputnik went up, Eisenhower was all business about getting us into the race, Big Time.

As a side note, the original Collier's articles can be found easily and downloaded in their full color entirety using Google. I owned all the original magazines for years, until they were disintegrating and were thrown out by my mother whilst I was away in the Army.

Last edited by Oldfart1939 (2021-02-06 15:26:06)

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#914 2021-02-06 11:34:08

GW Johnson
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Posts: 5,459
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Re: Starship is Go...

Oldfart1939:

I never saw the actual Collier's magazines,  but that same material was published in,  or inspired related articles,  in some other magazines and books.  Most notably,  it inspired the Disney classics about going into space that I saw on TV at the time.  I have these on DVD in color (TV was black and white in the early and mid 1950's),  and they remain amazingly close to the mark even today. 

I do seem to remember an Atlas launch about 1958 into orbit that resulted in the first transmission of an image via satellite.  It was an image of the crew on the flight deck of a carrier out at sea.  Atlas still had a serious reliability problem in those days,  and it still was a risk when Glenn first rode one in 1962.

From what I have read,  von Braun had a means to launch a small satellite with the Jupiter-C version of Redstone as early as 1956.  But the political decision was made that Vanguard would be first,  and some say a part of this was getting the "open skies" policy accepted by the Russians by letting them fly first with Sputnik 1.  Some others deny that last;  myself,  I don't know for sure.

The rocket plane projects would occasionally hit the news stories in the 1950's,  but it was the newly-formed NASA with its civilian Mercury program that got most of the publicity,  starting about 1958,  right after NASA's formation.  They were still flying the D-558-2 Skyrocket and the X-1 variants along with the X-2,  until about 1958 when the X-15 first rolled out.  That one actually did reach the definition of space once equipped with the big XLR-99 engine and drop tanks.  Lots of X-15 pilots actually won astronaut wings. 

Gemini was really just a slightly-upsized Mercury to carry two astronauts.  It needed a larger booster,  and that was the then-brand-new Titan-2.  It was Apollo that was an entirely different capsule design.  There were some studies of landing a Gemini launched by a Saturn-1 on the moon,  but that was inherently a one-way suicide trip.  Not popular,  and just a desperation choice to try to beat the Russians to the moon. 

What I remember about the genesis of Apollo comes from the predecessor to Aviation Week magazine.  I do remember seeing stuff about a capsule/giant two-stage service module that was to land directly on the moon.  That concept was still in one of von Braun's books as late as 1964 or 1965.  It took two Saturn 5 launches per mission,  with on-orbit refueling,  to do it that way. 

The notion of lunar orbit rendezvous is what got them down to one Saturn-5 per mission,  and it came from outside NASA.  There was resistance to it,  but what finally won the day was twofold:  (1) one launch per mission (lower cost),  and (2) no need to develop on-orbit refueling with cryogenics.  They thought they could not get that second thing done until well after 1970,  and probably rightly so.

There was to be a USAF delta-wing spaceplane launched by an advanced variant of the Titan missile (Titan-3,  still only a paper design then).  It was the X-20 "Dyna-Soar" (for "dynamic-soaring").  That one got cancelled in 1963 as the first 3 examples were about to come off the production line at Boeing.  The actual Titan-3 and Titan-4 variants are now part of launch vehicle history.

USAF and NASA already knew they could not launch an X-15 into orbit with a Titan-3,  because it could not survive reentry.  Whether the X-20 could have survived,  well,  who knows?  It was to be a flying test bed to explore refractory re-radiation cooling and active liquid cooling as alternatives to ablation.  It had Inconel-X skins like the X-15,  and graphite nose and leading edge pieces with embedded tungsten heat conductors.  Interesting design.  Never got to fly.

USAF's manned orbiting laboratory (MOL) was a Titan-3 launched school-bus-sized space station with a two man crew in a Gemini-B attached on top.  Gemini-B had a hatch through the heat shield.  The space station was really a manned spy satellite.  Its weight and dimensions were similar to the KH-11 unmanned spy satellites that Shuttle launched.  The Gemini-B actually flew once,  successfully and unmanned,  before MOL was cancelled in favor of KH-11.  That capsule is in a museum,  I think somewhere in the midwest.

As a graduate student in the 1972-1974 time frame,  I got to do hypersonic wind tunnel testing of proposed Space Shuttle nose shapes (actually the forward third of the vehicle) at UT Austin.  The professor had a NASA contract that covered exploratory work at UT,  followed by confirmation testing of the whole vehicle as a larger model at AEDC. 

What we found at UT was confirmed at AEDC:  (1) nose shape didn't matter all that much,  and (2) there were very strict AOA limits during entry,  such that too little or too much AOA led to the same outcome:  rapid windscreen failure leading to immediate cabin roof loss and destruction of the flight deck crew by wind blast. The limits were 20 to 40 degrees AOA.

We also found out at UT why this was:  it has to do with the effects of the lateral separation vortices alongside the nose upon the flow stream coming over the top of the nose.  Those vortices strengthen dramatically as AOA increases. 

Too low an AOA and you get direct still-attached hypersonic wind blast upon a transparency that cannot survive that. Higher,  and you get separated flow over the nose that jumps over the cabin roof.  Too high,  and the far-stronger vortices pull that flow over the nose back down into attaching to the surface,  and thus running smack into the transparency again,  which cannot survive. 

That's how I learned very early on that high speed aerodynamics can be a real bitch.

GW

Last edited by GW Johnson (2021-02-06 11:39:58)


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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#915 2021-02-06 21:02:26

SpaceNut
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Posts: 28,882

Re: Starship is Go...

Here is some more of those half truths lies about what is what as Biden administration backs US Moon shot
article goes on to say "initiated under his predecessor Donald Trump." going back to the moon was started back in 2004 when shuttle was getting canned as being to experimental.

The 2024 date has been in doubt because of a funding shortfall for the landing element, which will carry astronauts from lunar orbit down to the surface.

Nasa had asked for $3.3bn to fund the Human Landing System (HLS) in 2021 but received only $850m, which is likely to impact the schedule.

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#916 2021-02-07 13:32:28

Oldfart1939
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Registered: 2016-11-26
Posts: 2,384

Re: Starship is Go...

The old saw about "Money Talks," is true here, as the states with potential contractors have had their congressional representatives speaking out in favor of the Artemis project. Here in Colorado, both U.S. Senators (both Democrats) have come out with strong supporting statements. But no wonder; Lockheed-Martin is Colorado based, as is Sierra Nevada Corporation. Both have big (potential) roles to play in a moon landing. Senators from Washington, and California have thrown their support to this project (Boeing is in Washington, and SpaceX in California). Space is popular as a jobs creator and hence, vote gatherer.

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#917 2021-02-07 13:38:53

Oldfart1939
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Registered: 2016-11-26
Posts: 2,384

Re: Starship is Go...

For those who would like to peruse these phenomenally accurate predictors of the future (Collier's magazine), here's a link to guide you there:

https://www.rmastri.it/spacestuff/wernh … 1952-1954/

Last edited by Oldfart1939 (2021-02-07 16:01:55)

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#918 2021-02-07 16:06:39

GW Johnson
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From: McGregor, Texas USA
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Posts: 5,459
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Re: Starship is Go...

Wow,  those illustrations from Collier's do bring back the memories!  While I didn't see them in that magazine per se,  those same illustrations made their way into a lot of publications back then.  And I did see them!  Thanks!

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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#919 2021-02-07 19:44:40

SpaceNut
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Re: Starship is Go...

Have we found any engine views for this sn9 flight as it would be interesting to compare to sn8 for the shut off of fuel engine bouncing....

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#920 2021-02-08 21:43:58

SpaceNut
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Re: Starship is Go...

Next up SN10’s Raptors installed ahead of testing and refined landing attempt

We were too dumb. It was foolish of us not to start 3 engines & immediately shut down 1, as 2 are needed to land.”

Looks like they learned from not going with all engines and shutting them down if not needed.

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#921 2021-02-09 10:28:59

GW Johnson
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Re: Starship is Go...

If you follow the link in Spacenut's post 920 just above,  one of the pictures there shows a view of a reddish-looking fire in the engine bay of SN-9,  something I saw in the video of this flight that Spacex posted on their website.  I haven't seen any protective insulations wrapped onto these engines,  so a fire in the bay could easily damage such plumbing and wiring.  That would include the igniter,  which I believe to be a gas torch,  not TEB injection.  The fire points to a small fuel leak into the bay,  because leaked oxygen would not do that burning-with-air thing.  "Small" because the engine did not run oxygen-rich and burn green,  the way SN-8 did,  with seriously-low fuel feed pressure.

My own opinion is they are taking too high a risk waiting to the last second to flip and land.  That wait saves propellant,  but you get into fault tree troubles with single point failures causing disasters.  So far,  it has caused two crashes.   That being said,  lighting 3 engines for the flip is a valid idea to pursue.  Myself,  I would simply use the 3 at about 2/3 max thrust capability each,  for the same thrust as two engines at full thrust setting. 

I know that the Isp is lower at reduced thrust setting,  causing you to need more propellant,  but it is not a large quantity we are talking about.  If you have three engines running at reduced thrust,  it is easy to throttle up for more deceleration,  in the event something went wrong with vehicle guidance and control,  putting you at lower altitude to start the touchdown than you intended.  You cover more single-point failure modes in the fault tree that way.  So what if you need 30 tons of propellant to land instead of 20?  You have fewer crashes,  and that is a huge benefit!

Spacex went through this difference once before:  between being an expert in making rocket engines work,  and being an expert in flying a unique supersonic vehicle.  That was the 3 first-flight losses with Falcon-1 that almost bankrupted them before they could get going.  The same sort of thing is happening again,  this time with a different supersonic vehicle that has to "stick" a last-second subsonic propulsive landing.  No one has ever done that before,  not even the DC-X;  there are no experts! 

Crashes until they learn all these vehicle nuances,  should be expected.

GW

Last edited by GW Johnson (2021-02-09 10:31:51)


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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#922 2021-02-12 20:16:55

SpaceNut
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Re: Starship is Go...

Starship SN10’s Raptors installed as testing beginsNSF-2021-02-07-23-06-16-827-1170x755.jpg

image explaining the pivot on the center of mass
EtafrQeUcAUwaJx?format=jpg&name=small


Get ready for the heavy
NSF-2021-02-07-22-17-06-633.jpg

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#923 2021-02-16 09:58:16

GW Johnson
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Re: Starship is Go...

I added a S/N-8,  S/N-9-like test flight to the examples of my rocket vehicle performance spreadsheet article on "exrocketman".  It would seem to suggest they are not yet flying the max propellant loads that 3 sea level Raptors can lift,  so we can indeed expect to see some more-demanding test flights,  once they learn how to stick a landing without crashing. 

Myself,  I'd approach this difficult landing problem suspenders-and-belt,  armored codpiece.  I'd light 3 engines to do the flip,  but I'd leave all 3 running,  and just throttle back to the design thrust level.  If only 2 light,  leave them at full thrust. 

If 1 of the 3 fails and shuts down,  you can throttle the other 2 up much faster than you can relight either the 1 you chose not to light if you use only 2,  or the 1 that shut down,  if you can relight it at all.  That's "fault tree 101" stuff with a 3-engine vehicle. 

I'd also start the flip much earlier,  just in case there is a problem achieving the requisite 2-engine near-full-thrust level.  That way there is sufficient altitude available for the lesser available deceleration to actually kill the descent velocity.  Not having that altitude in the event of unexpected low thrust is exactly why both S/N-8 and S/N-9 crashed.

Both of these actions cost more propellant for the landing,  because delivered Isp's are lower at lower thrust settings,  and you are burning longer.  But so what?  The propellant quantities still aboard are low regardless,  so this is not a large effect upon that landing mass.  If it staves off a crash,  is that not well worth it?   

GW

Last edited by GW Johnson (2021-02-16 10:05:56)


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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#924 2021-02-20 14:07:04

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,882

Re: Starship is Go...

https://www.msn.com/en-us/news/technolo … d=msedgdhp

tahanson43206 wrote:

Here's another topic that is due for a refresh...

The report below is from an article on the closeout of the FAA review of a recent SpaceX launch/test flight.

"The FAA provided oversight of the SN9 mishap investigation conducted by SpaceX. The SN9 vehicle failed within the bounds of the FAA safety analysis," the statement continued. "Its unsuccessful landing and explosion did not endanger the public or property. All debris was contained within the designated hazard area. The FAA approved the final mishap report, including the probable causes and corrective actions."

It is good to see this outcome of a collaboration between an entrepreneur who does NOT want to be regulated, and the regulators who do NOT want to slow him down any more than absolutely necessary.

(th)

Good to know as SN 10 is being readied for engine testing.

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#925 2021-02-21 11:21:24

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,384

Re: Starship is Go...

My thoughts, in following up on what GW clearly stated: They should fly with the maximum payload in fuel that the 3 Raptors can handle and then land with a heavier rocket (unburned fuel). Wouldn't need to be a lot, but enough to warrant using 3 Raptors and more than their danger point of flame outs. The problem of de-fueling the Starship would then exist after landing.

Last edited by Oldfart1939 (2021-02-21 11:23:57)

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