Starship is Go...

Oldfart1939 · 2021-04-15 15:22:19

Musk states that SN 15 will fly next week.

Not one of my favorite links about SpaceX: https://www.youtube.com/watch?v=qdH-VulltHI

Last edited by Oldfart1939 (2021-04-15 16:07:59)

louis · 2021-04-15 17:23:35

Crappy robot voices are always annoying! lol

This has got to be one of the most exciting launches of all!

If they can succeed with this new model then it's full steam ahead for Mars but if problems persist and we see fire followed by explosion again then it suggests the design has some fundamental flaws which may take a long time to address.

So hoping this flight is fully successful...well by fully I mean "doesn't end in an explosion".

Oldfart1939 wrote:

Musk states that SN 15 will fly next week.
Not one of my favorite links about SpaceX: https://www.youtube.com/watch?v=qdH-VulltHI

louis · 2021-04-16 13:51:59

Felix compares and contrasts SN15 with SN10 ...

https://www.youtube.com/watch?v=8c4Z6Iv2A8E

SpaceNut · 2021-04-18 13:20:43

Just watched my first Felix utube video and was quite a bit better done than the convention videos.

Felix covered the fabrications shaping of key transition area with the nose area, the end of wing cover and external wireway plus plumbing that goes from high to low as well as air resistance drag changes.
Also covered was first fabrication of the booster stage dress rehearsal construction.

SpaceNut · 2021-04-18 16:50:36

heat shield close up

lunar legs

louis · 2021-04-18 17:34:01

The legs are a bit more convincing in that rendering.

Was it something like 790 tiles on the SN15? Don't think we've seen any fall off yet - a good sign!

SpaceNut wrote:

heat shield close up
https://www.nasaspaceflight.com/wp-cont … 50-233.jpg
lunar legs
https://www.nasaspaceflight.com/wp-cont … 41-832.jpg

louis · 2021-04-21 14:53:25

Looks like SN15 is scheduled to launch 23 April at 13:00 local time.

Anyone able to confirm that?

SpaceNut · 2021-04-21 19:10:34

They have begun to put it through the testing phase so its coming soon for sure.
https://www.nasaspaceflight.com/2021/04 … r-testing/

tahanson43206 · 2021-04-21 20:52:14

For SpaceNut re #1083

Thanks for the link to that long and encouraging article ...

I noticed this later on in the piece, and wondered if all that testing is audible to GW Johnson ???

Every new engine built at SpaceX’s factory in California passes through McGregor ahead of being sent to the launch site as a unit or as part of a rocket stage.
The facility has grown in size during its SpaceX tenure, with the addition of numerous test stands, including the conversion of the original stalwart Falcon 9 tripod stand, which now hosts vertical Raptor testing.
Raptor engines are also tested in two horizontal bays, with long duration testing now into the SN60 range, the engines with the cited improvements. The second Raptor Vac (RVac) was also spotted on the horizontal stand last week via NSF’s Gary Blair in the L2 McGregor section, a local who flies past the test site at around 3,000 feet AGL.

(th)

GW Johnson · 2021-04-22 12:44:46

Any of the larger engine tests get heard all over half each of two counties. Yep, I hear them. My porch is 6 miles from their test site (that's 10 km for metric aficionados, BTW). Doors and windows get rattled hard enough to worry about cracks. Oddly enough, it's about the same in downtown McGregor, at 3 miles from the test stands.

GW

SpaceNut · 2021-04-26 18:14:08

This is not whom we should trust or follow Elon Musk admits ‘a bunch of people will probably die’ in early missions to Mars

Dead will end the program....

Oldfart1939 · 2021-04-27 16:02:11

SN 15 was successfully static fired, and Musk stated that the rocket will fly "this week."

louis · 2021-04-28 07:07:23

Here's the tweet:

https://twitter.com/elonmusk/status/1386836238771105793

Oldfart1939 wrote:

SN 15 was successfully static fired, and Musk stated that the rocket will fly "this week."

I saw reference in a thread to "legal challenges". Are these from local residents affected by noise and other disturbance do we know?

SpaceNut · 2021-04-29 21:25:32

FAA authorizes SpaceX's next three Starship test launches

So is this 3 swings and you are out or will they get it right finally

Oldfart1939 · 2021-04-30 09:12:57

The launch of SN 15 is starting coverage at 10:00 AM MDT through several of the YouTube channels: Everyday Astronaut, NASA Spaceflight; and What About It.

louis · 2021-04-30 10:30:18

Today? Exciting! I thought they had to fit a new Raptor engine or something...

I know every test is important but this was one is super-important! They've made many improvements...but have they addressed the challenges of the return to ground to avoid the catastrophic fires? If they have then an orbital flight can't be far away...if they haven't, this might be a far more difficult problem to overcome than first thought.

Oldfart1939 wrote:

The launch of SN 15 is starting coverage at 10:00 AM MDT through several of the YouTube channels: Everyday Astronaut, NASA Spaceflight; and What About It.

Oldfart1939 · 2021-04-30 11:53:01

I'm currently watching the Everyday Astronaut coverage.
Road closure is in effect. Cars leaving the beach areas.

Oldfart1939 · 2021-04-30 12:11:03

Scrubbed for today.

SpaceNut · 2021-04-30 16:05:38

louis wrote:

The legs are a bit more convincing in that rendering.
Was it something like 790 tiles on the SN15? Don't think we've seen any fall off yet - a good sign!

SpaceNut wrote:
heat shield close up
https://www.nasaspaceflight.com/wp-cont … 50-233.jpg
lunar legs
https://www.nasaspaceflight.com/wp-cont … 41-832.jpg

Up until now with no survivors we could not tell but the test run of the engines some came off

https://youtu.be/Lbhai7z2wYo

louis · 2021-04-30 16:24:47

Felix's latest:

https://www.youtube.com/watch?v=4qPRwsWjZqw

He seems pretty optimistic about prospects for the Starship test flight - now looking good for next week.

Nice section on the huge Integration Tower which will house the Starship-Booster stack.

Work on orbital SN20 already under way!

Last edited by louis (2021-04-30 16:29:45)

louis · 2021-04-30 16:25:57

Whoops! Well that is another thing they will need to get right.

SpaceNut wrote:

louis wrote:
The legs are a bit more convincing in that rendering.
Was it something like 790 tiles on the SN15? Don't think we've seen any fall off yet - a good sign!

SpaceNut wrote:
heat shield close up
https://www.nasaspaceflight.com/wp-cont … 50-233.jpg
lunar legs
https://www.nasaspaceflight.com/wp-cont … 41-832.jpg

Up until now with no survivors we could not tell but the test run of the engines some came off
https://youtu.be/Lbhai7z2wYo

RobertDyck · 2021-04-30 17:08:08

Just want to mention. I read a science fiction book that included a rocket landing on its tail with thrust designed to zero vertical motion exactly at touch-down. In the book, humans took a rocket to another planet. Space aliens insisted on controlling the rocket from the ground. Humans would normally hover briefly over the landing pad, then gently touch down. But alien flight controllers insisted on rapid descent, then high thrust to reduce velocity quickly at the last second, achieving zero velocity just as landing legs touched down. Very fuel efficient, but left those in the rocket rattled.

The book was one of the Skylark series. The first one?

louis · 2021-04-30 17:40:06

Thinking about Space X's rocket catcher and what you wrote there made me wonder if something like the following system might work:

You have a tower with an internal catchment area at the base of which is an inert gas tank under very high pressure - as the rocket comes into land, the inert gas is released, slowing down the rocket for a perfect landing. Wouldn't work for a first landing on Mars but later on could save on rocket fuel load, allowing for more cargo.

RobertDyck wrote:

Just want to mention. I read a science fiction book that included a rocket landing on its tail with thrust designed to zero vertical motion exactly at touch-down. In the book, humans took a rocket to another planet. Space aliens insisted on controlling the rocket from the ground. Humans would normally hover briefly over the landing pad, then gently touch down. But alien flight controllers insisted on rapid descent, then high thrust to reduce velocity quickly at the last second, achieving zero velocity just as landing legs touched down. Very fuel efficient, but left those in the rocket rattled.
The book was one of the Skylark series. The first one?

GW Johnson · 2021-05-02 10:23:52

I think catching a landing rocket with surface-mounted hardware is very likely to remain a Rube Goldberg pipe dream. Precisely because it is Rube Goldberg. Too Rube Goldberg to actually work.

I also think Spacex is learning (the hard way) that thrusting hard for a last-second zeroing of velocity is NOT the way to reach the high reliability for landing manned craft. That has been working with Falcon cores, but there are no lives involved, and those cores are far smaller vehicles. The bigger the vehicle, the harder it is to fly with that kind of precision close to the ground. Big enough, and even the robot cannot do it.

Multi-engine reliability is utterly required for retropropulsive landings, but you have to start the burn earlier, in order to recover from a sudden engine out at ignition or during the burn! There is just NO WAY around that requirement! Why? Here's why: unexpectedly-lowered thrust means it takes more time (and altitude) to get slowed sufficiently. Simple as that. We've already seen them demonstrate exactly that effect, multiple times.

So you fire up early at reduced thrust, and throttle-up to full, only if need be. Thus it becomes entirely feasible to slow to a hover off the surface, then touch down gently, regardless of the deceleration history leading to that point. But, you WILL burn more propellant doing that. No way around that, either, because Isp is lower at reduced thrust, and a hover touchdown costs lots of burn. Which is why I factor-up the landing ideal delta vee by 1.5 to 2.

Sometimes you just have to incur a larger propellant burn to get the reliability (and safety) that you MUST have for manned (or high-value unmanned) operations. Ugly little fact of life. Deal with it, or else fail! As I already said, Spacex is still learning the hard way to deal with it. Some of us could have told them (and saved them some failures), but they prefer not to ask us outsider oldsters.

The Starship landing leg designs are beginning to look a bit more credible for the concept illustrations of the lunar lander version of Starship. Before this testing is done, all versions of Starship will have legs more like those, despite the problems integrating legs with entry heat shields (really tough design problem, that!) You need those legs for off-site emergency landings, even with just orbital transport and orbital tanker Starships. But they haven't dealt with that issue yet. They will have to deal with it, or else they will fail.

They do seem to like to learn the hard way! Typically, most large organizations suffer from the same or similar attitudes. "Not invented here" is the usual term used for that. Government labs are really, really bad about it, but commercial firms also suffer from it. Spacex certainly does. And not hiring anybody over 45 who might know better makes it worse. They do that to get chronic 80-hour weeks out of employees. Older people just cannot sustain that pace indefinitely.

GW

Last edited by GW Johnson (2021-05-02 10:35:20)

Oldfart1939 · 2021-05-02 11:28:54

GW-

Some of the ideas that Elon has proposed do fall into the realm of Rube Goldberg devices, but Elon has a lot of wishful thinking dreams that he can afford to pursue. I'm skeptical that he can make landing the Super Heavy by catching it with his tower will work, but he seems to think that it's do-able. The hover-slam landings of Falcon 9 seems to be well-refined now, but as you commented about the increased weight of Starship and need for more than a single engine running at a time will probably just be another step on the learning curve for the SpaceX engineers.

P.S. added in edit: The landing legs concept on the Lunar Starship are still too narrow w/r to the height of the vehicle.

Last edited by Oldfart1939 (2021-05-02 11:31:22)

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