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-   -   What "weed need" is a space mission! (https://www.mersenneforum.org/showthread.php?t=17609)

kladner 2020-04-28 03:26

[QUOTE=chalsall;543973]I don't have references immediately at hand, but I've read from credible sources that several of the emergency oxygen supplies were activated, and used, during the decent.
[U]
Dan Simmons' [URL="https://en.wikipedia.org/wiki/Prayers_to_Broken_Stones#%22Two_Minutes_Forty-five_Seconds%22"][I]Two Minutes Forty-five Seconds[/I][/URL] short story in his [I]Prayers to Broken Stones[/I] collection coldly covers the topic.[/U][/QUOTE]
Thank You Chris! We have that book. I referred to this story earlier, but could not remember the source. Simmons is a seriously engaging author. This story really affected me. IIRC, the protagonist had opposed the low-temperature launch, but was strong-armed by managers to sign off on it.

chalsall 2020-05-01 18:00

[QUOTE=kladner;544030]Simmons is a seriously engaging author. This story really affected me.[/QUOTE]

Ditto. I briefly thought about being a SciFi author (as a hobby), until I read some of his work. Then I realized there was ("like") zero chance I could ever hope to touch that level...

He's also very multi-disciplinary. Love his horror work, as well as his /Joe Kurtz/ series.

However, I found his later work to be less rewarding. /Druid/ is a meandering waste of time, and I disliked that some of his recent output revealed a bit of a, shall we say, extreme right-wing slant...

kladner 2020-05-01 18:07

[QUOTE=chalsall;544384]Ditto. I briefly thought about being a SciFi author (as a hobby), until I read some of his work. Then I realized there was ("like") zero chance I could ever hope to touch that level...

He's also very multi-disciplinary. Love his horror work, as well as his /Joe Kurtz/ series.

However, I found his later work to be less rewarding. /Druid/ is a meandering waste of time, and I disliked that some of his recent output revealed a bit of a, shall we say, extreme right-wing slant...[/QUOTE]
Hyperion series is a great favorite here.

storm5510 2020-05-01 18:22

Amazing! Not a peep here from anyone about a crewed SpaceX Dragon flight on May 27th to the I.S.S. :shock:

xilman 2020-05-01 19:13

[QUOTE=storm5510;544390]Amazing! Not a peep here from anyone about a crewed SpaceX Dragon flight on May 27th to the I.S.S. :shock:[/QUOTE]What!

I think I am responding to a peep. Perhaps I am hallucinating.

Uncwilly 2020-05-01 19:20

People will be losing it (their minds) in the week before.

storm5510 2020-05-02 00:23

[QUOTE=xilman]What!

I think I am responding to a peep. Perhaps I am hallucinating.[/QUOTE]

:cool:

[QUOTE=Uncwilly]People will be losing it (their minds) in the week before.[/QUOTE]

I expect so, especially if they cannot be there, in person, watching. The boat crowd may not have any problems though.

:smile:

Uncwilly 2020-05-02 00:35

[QUOTE=storm5510;544426] I expect so, especially if they cannot be there, in person, watching. The boat crowd may not have any problems though.[/QUOTE]The range safety exclusion zone is large. And since this is launch with an active launch escape system the exclusion area near the pad will likely be larger.

storm5510 2020-05-02 13:27

[QUOTE=Uncwilly;544427]The range safety exclusion zone is large. And since this is launch with an active launch escape system the exclusion area near the pad will likely be larger.[/QUOTE]

Way back in 1981 when Columbia flew the first time, I saw photos of boaters pulled in close to the beaches north and south of the launch area. Of course, that was nearly 40 years ago.

I remember watching a video of the escape system test a few months ago. Having it built into the sides was interesting. No need for the tower on top like Apollo used. I suppose the only things under the cap on top is the docking collar and parachute system.

I wonder if anyone on the I.S.S. now has been cross-trained to fly it back down? I have not seen anything about it.

Uncwilly 2020-05-02 14:37

[QUOTE=storm5510;544450]I wonder if anyone on the I.S.S. now has been cross-trained to fly it back down? I have not seen anything about it.[/QUOTE]The plan had been to have Bob & Doug visit for approximately 2 weeks. But, it has been decided to extend their mission. Currently the plan (as I understand it) is to have them stay up until about 1 month before Crew 1 goes up. That gives NASA and SpaceX a month to look at the data and address any minor issues.

NASA is asking people to stay away because of COVID.

storm5510 2020-05-02 16:42

[QUOTE=Uncwilly;544454]The plan had been to have Bob & Doug visit for approximately 2 weeks. But, it has been decided to extend their mission. Currently the plan (as I understand it) is to have them stay up until about 1 month before Crew 1 goes up. That gives NASA and SpaceX a month to look at the data and address any minor issues.

NASA is asking people to stay away because of COVID.[/QUOTE]

"...before Crew 1 goes up." This seems like a Soyuz hitchhike to get a pair there to bring the Dragon back. I have not done much reading about all of this as my eyes are not so great anymore, even with glasses.

axn 2020-05-02 16:59

[QUOTE=storm5510;544461]"...before Crew 1 goes up." This seems like a Soyuz hitchhike to get a pair there to bring the Dragon back.[/QUOTE]

No. Crew 1 is the first official mission for Crew Dragon. The currently slated mission is Demo 2.

EDIT:- My guess is, before Crew 1 goes up, Bob & Doug will get on the docked Crew Dragon and come down.

Uncwilly 2020-05-02 20:26

[QUOTE=axn;544463]No. Crew 1 is the first official mission for Crew Dragon. The currently slated mission is Demo 2.

EDIT:- My guess is, before Crew 1 goes up, Bob & Doug will get on the docked Crew Dragon and come down.[/QUOTE]
Yes, both of these.

kladner 2020-05-03 14:29

[QUOTE=kladner;544386]Hyperion series is a great favorite here.[/QUOTE]
I just picked up on your last remark, Chris. The extreme Right report is disturbing. Niven showed some such signs, though around here we attribute that to his association with Pournelle.

xilman 2020-05-19 12:42

I found this very impressive [YOUTUBE]su9EVeHqizY[/YOUTUBE]

Note how the Falcon Heavy reaches orbit much earlier than the others, and just how long the Saturn takes before it even ignites the 3rd stage.

Also, see the relative positions of LOX, kerosine and LH2. The solid boosters burn from the inside outwards, something which I have known since I was a kid but you would be surprised at how many people think they burn from the bottom upwards.

storm5510 2020-05-19 13:22

[QUOTE=xilman;545838]...The solid boosters burn from the inside outwards, something which I have known since I was a kid but you would be surprised at how many people think they burn from the bottom upwards.[/QUOTE]

I always thought they burned from the bottom up. This made Challenger's o-ring burn-through easy to grasp. From the center out makes sense as exterior would not heat near as much. This make the o-ring problem a bit more muddy. I believe the solid's are stacked in segments during assembly. If there were the slightest gap between two of the segments, internally, then I can see how it would be a problem.

I dabbled with model rockets when I was a kid. It always amazed me how thick and hard the sides of the propellant casings were. Each had a tapered bore into the propellant.

LaurV 2020-05-19 13:35

[QUOTE=xilman;545838]I found this very impressive [/QUOTE]
I don't really... It teaches nothing non-obvious. What did you believe it was inside a rocket? There should put some indicators with speed, altitude, I just wasted 5 minutes (speed view) watching four colored balls doing nothing on screen. Much more impressive (for me) seems this one (linked from your link), where I actually learned something ...

[YOUTUBE]HyL36bH8PP8[/YOUTUBE]

Uncwilly 2020-05-19 14:00

[QUOTE=xilman;545838]The solid boosters burn from the inside outwards, something which I have known since I was a kid but you would be surprised at how many people think they burn from the bottom upwards.[/QUOTE]

[QUOTE=storm5510;545842]I always thought they burned from the bottom up. This made Challenger's o-ring burn-through easy to grasp.[/QUOTE]
That view presented is a 1/2 truth. The STS SRB's and other such rockets have different patterns. The "grain", as the individually prepared section of propellant are called, have different shapes. Some have a multipoint star pattern to provide maximum thrust at takeoff and then as the star burns the thrust goes down (as does the weight of the rocket). The acceleration can still go up. If the STS SRB's burned from the center outward, the burning surface area would go up as they burned. This would increase thrust as the mass has gone down. This would ramp up the acceleration. Burning from the end would not be fast enough, nor provide enough surface area/thrust. So, what was done for the STS STRB's (and many other systems where max acceleration is limited (meat sacks don't like too many G's) is to have a grain that has a whole in the center, but also is not touching the grains above and below them. They burn from the inside out [B][U]and[/U][/B] from top and bottom toward the middle. This give a near constant burning surface area. You will hear that the STS SRB's are 4 segment, while the SLS SRB's are 5. IIRC each segment has 2 grains in it.

Uncwilly 2020-05-30 21:45

So we had a launch today.
There was a lot of 'Murica going on. At least once I heard Murica^4.

ewmayer 2020-05-30 23:42

[QUOTE=Uncwilly;546834]So we had a launch today.
There was a lot of 'Murica going on. At least once I heard Murica^4.[/QUOTE]

Were the usual U-S-A chants replaced by one of T-S-LA(y) in honor of Musk's [url=https://finance.yahoo.com/news/tesla-ceo-elon-musk-awarded-214955380.html]recent $700M bonus[/url] for putting the above-chanted-stock-symbol company's share price into an even higher orbit than the astronauts in today's launch?

And, what was the approximate ratio of NASA to MAGA swag in the crowd?

Uncwilly 2020-05-31 00:31

[QUOTE=ewmayer;546838]And, what was the approximate ratio of NASA to MAGA swag in the crowd?[/QUOTE]The official webcast did not show crowds.

ewmayer 2020-05-31 00:43

[QUOTE=Uncwilly;546839]The official webcast did not show crowds.[/QUOTE]

A few good pics - none of crowds, just one of cheering beachgoers - in this [url=https://www.theguardian.com/science/2020/may/30/spacex-nasa-crewed-spaceflight-launch-dragon-capsule-elon-musk-trump]Guardian piece[/url]. I like the picture of Trump: "uh, Mr. President, the launch is *that* way, behind you." Busy gauging at how many people are watching *him*, no doubt. But good PR is good PR...

retina 2020-09-06 11:18

Not sure if this all just pure woo, but ...

[url]https://www.wired.com/story/mach-effect-thrusters-interstellar-travel/[/url] [quote]Woodward’s MEGA drive is different. Instead of propellant, it relies on electricity, which in space would come from solar panels or a nuclear reactor. His insight was to use a stack of piezoelectric crystals and some controversial—but he believes plausible—physics to generate thrust. The stack of crystals, which store tiny amounts of energy, vibrates tens of thousands of times per second when zapped with electric current. Some of the vibrational frequencies harmonize as they roll through the device, and when the oscillations sync up in just the right way, the small drive lurches forward.

...

In Einstein’s famous equation, E=mc2, an object’s energy, E, is equal to its mass, m, multiplied by the speed of light squared. That means if you change an object’s energy, you will also change its mass. An object’s mass is a measure of its inertia—that’s why it takes greater force to push a more massive object than a less massive one—so changing its energy will also change its inertia. And if, per Mach’s principle, inertia and gravity are one and the same, then changing an object’s energy means messing with the very fabric of spacetime. In theory, anyway.

Woodward realized that if Einstein was right and inertia really is gravity in disguise, it should be possible to detect these brief changes in an object’s mass as its energy fluctuates. If part of an object accelerated at the exact moment when it became a little heavier, it would pull the rest of the object along with it. In other words, it would create thrust without propellant.

Woodward called these temporary changes in mass “Mach effects,” and the engine that could use them a Mach-effect thruster. By combining hundreds or thousands of these drives, they could conceivably produce enough thrust to send a spaceship to the stars in less than a human lifetime. How to keep a person alive in space for decades is still an enormous question. But it is a mere footnote to the more fundamental issue of figuring out how to cross a void trillions of miles wide in any reasonable amount of time.[/quote]

Dr Sardonicus 2020-09-06 12:12

[QUOTE=retina;556216]Not sure if this all just pure woo, but ...

[url]https://www.wired.com/story/mach-effect-thrusters-interstellar-travel/[/url][/QUOTE]Another article with pictures and equations [url=http://ssi.org/wp-content/uploads/2018/02/ssiapw2017_12_fearn.pdf]here[/url].

It is not clear to me why this thing wouldn't violate conservation of momentum.

firejuggler 2020-09-06 12:57

This one is more on the funny side.

[url]https://twitter.com/PercyRover[/url] is a parody twitter account about the Perseverance probe. It identify as LatinX, and has a secondary account for Ginny, the helicopter that goes to mars with it. Also the account engage in political matter.

Nick 2020-09-12 11:36

Do you dig the moon? [URL="https://beta.sam.gov/opp/77726177617a45d0a196e23a587d7c14/view"]NASA is buying.[/URL].

retina 2020-09-14 13:10

[QUOTE=Dr Sardonicus;556219]It is not clear to me why this thing wouldn't violate conservation of momentum.[/QUOTE]It would also suggest that a capacitor will be heavier when charged than without charge, since the energy stored is supposedly higher. Same for an inductor and the magnetic field. And I guess also for anything at a higher temperature.

Dr Sardonicus 2020-09-14 13:55

[QUOTE=retina;556940]It would also suggest that a capacitor will be heavier when charged than without charge, since the energy stored is supposedly higher. Same for an inductor and the magnetic field. And I guess also for anything at a higher temperature.[/QUOTE]
I don't have a problem with that. Energy has mass. Of course, the energy that goes [i]into[/i] the capacitor or into heating something has to come [i]out of[/i] something [i]else[/i], and that something else will become correspondingly less massive. The equivalent mass is given by

m = E/c[sup]2[/sup],

which will be be pretty small in or near any molecular material whose atomic nuclei you want to remain intact.

What I have a problem with is a spacecraft's momentum changing ("Delta em-vee") without propellants, because it is less than clear to me what is acquiring the equal and opposite change in momentum required by conservation of momentum.

retina 2020-09-14 14:10

[QUOTE=Dr Sardonicus;556947]Of course, the energy that goes [i]into[/i] the capacitor or into heating something has to come [i]out of[/i] something [i]else[/i], and that something else will become correspondingly less massive.
<snip>

... atomic nuclei you want to remain intact.[/QUOTE]The article mentions solar and atomic as potential energy sources. When the thing is heavier move it left, and when it is lighter move it right. So even if energy is transferred from a battery then move the battery one way, and the cap/piezo/thing the other way. I can see how CoM is maintained there. Of course that doesn't mean it works, just that CoM looks to be fine AFAICT.

firejuggler 2020-09-14 16:57

We need to go back to look at Venus.

Phosphin, a gas associated with bacterial life ( on earth, at least) has been found in the middle layer of Venus athmosphere. [URL]https://www.nationalgeographic.com/science/2020/09/possible-sign-of-life-found-on-venus-phosphine-gas/[/URL]
[URL="https://www.planetary.org/articles/venus-phosphine-biosignature"]https://www.planetary.org/articles/venus-phosphine-biosignature [/URL]
[url]https://www.nature.com/articles/s41550-020-1174-4[/url]



But, as smbc said probably not alien [URL]https://www.smbc-comics.com/comic/2012-11-30[/URL] (yet)


Bepi-Colombo, the asteroïd probe, will use (two AFAIK) Venus gravity assist to come back with some sample. Maybe, it can do science on it's way back? ( well that was in the press briefing)


So no spiders life on mars but maybe microbial life on venus.

Uncwilly 2020-09-14 18:19

Rocket Lab has been planning a Venus trip for a while now:
[url]https://www.syfy.com/syfywire/rocket-lab-targets-venus-for-2023-life-searching-mission[/url]

Uncwilly 2020-09-15 16:49

Of course xkcd [XKCD]2359[/XKCD].
I think people have been too left column this week.

xilman 2020-09-25 20:23

[url]https://twitter.com/Trolley110/status/1309218356873121793[/url]

(Rocket scientists build classic design and prove that it works.)

tuckerkao 2020-09-25 21:29

[QUOTE=retina;323152]Thanks for the link. I think at a minimum the orbit has to be double the diameter of the Sun so that we can peek at the probe around the Sun's edges on a continuous basis. But practically I would expect the orbit needs to be larger than that to make signal reception more reliable.[/QUOTE]
The larger orbit will also be more functional for the Space Age Venus mission. The extremely high temperature and dense gravity will take some reliable devices to detect their unusual behaviors at times such as the inferno whirls.

retina 2020-09-27 08:52

[url]https://www.youtube.com/watch?v=dqwpQarrDwk[/url]

Apparently we can use Phobos as a gateway to the entire solar system. And not have to worry about it losing momentum, since it is heavy enough to handle it.

kriesel 2020-09-27 18:06

[QUOTE=xilman;557886][URL]https://twitter.com/Trolley110/status/1309218356873121793[/URL]

(Rocket scientists build classic design and prove that it works.)[/QUOTE]
A few posts lower on that twitter page, fleeing gave the rocket space to acquire more velocity before impact. Very understandable though. [url]https://twitter.com/i/status/1309511001235046405[/url]

kriesel 2020-09-27 18:25

space travel in style
 
Take everyone/everything in the solar system along. Plan for a long duration voyage. [url]https://www.youtube.com/watch?v=v3y8AIEX_dU[/url]

Mark Rose 2020-09-27 19:47

1 Attachment(s)
Not sure if this was ever posted here

Nick 2020-10-19 20:04

Nokia to build mobile phone network for the moon
[URL]https://www.nokia.com/about-us/news/releases/2020/10/19/nokia-selected-by-nasa-to-build-first-ever-cellular-network-on-the-moon/[/URL]

The moon doesn't appear to have a top-level domain name yet
(.lu is Luxembourg of course).

Uncwilly 2020-10-19 20:57

The asteroid Bennu is getting a up close and personal visit on Tuesday by OSIRIS/REx mission. [url]https://www.asteroidmission.org[/url] The spacecraft is going to touch the asteroid, blow on it and catch what gets stirred up. Then it will return that to earth for study. The asteroid was mapped in painstaking detail to select a site suitable. There were thousands of volunteers that marked millions of objects of this large city block size body. These amateurs let the professions select 4 possible sampling sites. NASA had agreed to this, and then when they saw that Bennu was basically mixture of gravel and rocks of various sizes, they were worried that the mapping might not get finished in time.

The people behind Zooniverse [url]https://www.zooniverse.org[/url] and CosmoQuestX made it happen. The power of distributed work by humans is amazing.

chalsall 2020-11-15 20:27

NASA/SpaceX Crew-1...
 
I'm surprised no one mentioned this...

Empirically, the bell-curve of US of A thinking is not completely insane... :wink:

[url]https://www.spacex.com/[/url]

Appoximately four (4#) hours from now... :smile: :tu:

Uncwilly 2020-11-15 21:11

[QUOTE=chalsall;563315]I'm surprised no one mentioned this...[/QUOTE]I had the feed running before they went live.
I really am wanting to see Crew 2 launch on a used Dragon.
Also, I hope when that happens Dee O'Hara can be on hand in the hallway leading out of the suit up room.

chalsall 2020-11-15 21:21

[QUOTE=Uncwilly;563324]I had the feed running before they went live.[/QUOTE]

Yeah... Me too. Like, four hours ahead of the feed going live I gave permission for local audio broadcast.

I have them muted at the moment (I personally can't deal with side-channel audio), but I drop into the video and text feed every twenty minutes or so to see what's going down (or, should that be, up...).

We live in extraordinary times.

Let's enjoy the ups, and manage the downs... :smile:

kladner 2020-11-15 21:40

I hope everything is copacetic this time. :smile:

Uncwilly 2020-11-15 21:53

SpaceX normally does a mission control audio only channel for it's launches.
Today's is:
[YOUTUBE]oMFLHc-GMh8[/YOUTUBE]

chalsall 2020-11-15 22:02

[QUOTE=kladner;563336]I hope everything is copacetic this time. :smile:[/QUOTE]

Seriously... When I grow up I want to be Musk.

Disagree with his breeding policies, but until he burns himself out he's doing some cool shit.

firejuggler 2020-11-30 17:31

ESA ([SIZE=2]Europe's Space Agency) Is Spending $103 Million to Remove a Single Piece of Space Junk[/SIZE]
[SIZE=2]https://www.esa.int/Newsroom/Press_Releases/Call_for_Media_ESA_and_ClearSpace_SA_sign_contract_for_world_s_first_debris_removal_mission[/SIZE]
[SIZE=2]
[/SIZE]
[code]

[SIZE=2]At ESA’s [URL="https://www.esa.int/About_Us/Corporate_news/ESA_ministers_commit_to_biggest_ever_budget"]Space19+[/URL] Ministerial Council, ministers granted ESA the funding[/SIZE]
[SIZE=2] to place a service contract with a commercial provider for the safe removal[/SIZE]
[SIZE=2] of an inactive object from low Earth orbit. Following a competitive process, an[/SIZE]
[SIZE=2] industrial team led by [URL="https://clearspace.today/"]ClearSpace[/URL] SA – a spin-off company of the[/SIZE]
[SIZE=2] Ecole Polytechnique Fédérale de Lausanne ([URL="https://www.epfl.ch/en/"]EPFL[/URL]) – was invited to submit[/SIZE]
[SIZE=2] the final proposal. With this contract signature, a critical milestone for[/SIZE]
[SIZE=2] establishing a new commercial sector in space will be achieved. Purchasing[/SIZE]
[SIZE=2] the mission in an end-to-end service contract, rather than developing an ESA-defined[/SIZE]
[SIZE=2] spacecraft for in-house operation, represents a new way for ESA to do business. ESA[/SIZE]
[SIZE=2] is purchasing the initial mission and contributing key expertise, as part of the Active[/SIZE]
[SIZE=2] Debris Removal/ In-Orbit Servicing project (ADRIOS) within ESA’s Space Safety[/SIZE]
[SIZE=2] Programme. ClearSpace SA will raise the remainder of the mission cost through commercial investors.[/SIZE]
[/code][SIZE=2]
[/SIZE]

diep 2020-11-30 18:15

[QUOTE=firejuggler;564845]ESA ([SIZE=2]Europe's Space Agency Is Spending) $103 Million to Remove a Single Piece of Space Junk[/SIZE]
[/QUOTE]

Money well spent. It's possible some years ago they suddenly saw so called 'debris' or junk in space actively move - hidden military satellites - designed to sabotage other satellites. With this you can clean up such debris and if it appears an enemy satellite cloaking it's a good catch.

Nick 2020-11-30 18:19

[QUOTE=firejuggler;564845]ESA ([SIZE=2]Europe's Space Agency Is Spending) $103 Million to Remove a Single Piece of Space Junk[/SIZE]
[SIZE=2]https://www.esa.int/Newsroom/Press_Releases/Call_for_Media_ESA_and_ClearSpace_SA_sign_contract_for_world_s_first_debris_removal_mission[/SIZE]
[/QUOTE]
I thought it was going to be one of the big letters circling the globe that spell out "UNIVERSAL"...

Uncwilly 2020-11-30 18:53

This would be a good test mission for [URL="https://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_Rocket"]VASIMR[/URL]

Dr Sardonicus 2020-11-30 18:57

[QUOTE=firejuggler;564845]ESA ([SIZE=2]Europe's Space Agency) Is Spending $103 Million to Remove a Single Piece of Space Junk[/SIZE]
[SIZE=2]https://www.esa.int/Newsroom/Press_Releases/Call_for_Media_ESA_and_ClearSpace_SA_sign_contract_for_world_s_first_debris_removal_mission[/SIZE][/QUOTE]
This has been in the works for some time. See [url=https://www.mersenneforum.org/showpost.php?p=563642&postcount=6]this post[/url] for a pertinent link.

Huh. Wrapping size tags around a web address prevents the Forum software from wrapping url tags around it. I had no idea. Good to know!

:tu:

diep 2020-11-30 19:42

[QUOTE=Uncwilly;564857]This would be a good test mission for [URL="https://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_Rocket"]VASIMR[/URL][/QUOTE]

Wikipedia not too optimistic about VASIMR. How comes?

[url]https://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_Rocket[/url]

James Heinrich 2020-12-09 20:08

[QUOTE=KEP;565793]... Now time to watch some SpaceX and hopefully a 12.5KM hop for starship :smile:[/QUOTE]Did they reschedule that?

Uncwilly 2020-12-09 20:21

[QUOTE=James Heinrich;565794]Did they reschedule that?[/QUOTE]
Currently SpaceX's YT channel is showing 38 minutes until their start.
[YOUTUBE]ap-BkkrRg-o[/YOUTUBE]

KEP 2020-12-09 21:29

[QUOTE=James Heinrich;565794]Did they reschedule that?[/QUOTE]

Not that early, as my message could imply and now unfortunantly a delay, so if it happens at 22:40 UTC, it sure will be too late for me to watch. Dang, we were so close :cry:

James Heinrich 2020-12-09 22:55

Certainly worth a watch if you missed it!

Uncwilly 2020-12-09 23:30

Link to today's test.
[url]https://youtu.be/ap-BkkrRg-o?t=6445[/url]

storm5510 2020-12-09 23:52

What was it that this vehicle was supposed to do? It did not turn out very well from the looks of it. :confused:

Uncwilly 2020-12-10 00:25

[QUOTE=storm5510;565808]What was it that this vehicle was supposed to do? It did not turn out very well from the looks of it. :confused:[/QUOTE]
It was supposed to land in the same orientation as it took off. It ran into low fuel pressure. The belly first fall was as planned. The flip to tail end down was as planned. It just didn't slow enough.

diep 2020-12-10 00:40

From what i wrote to someone on my chat regarding starship sn8.

I design CNC machines
i act as if i know something about hardware design
i do not understand why starship sn8 has inside 1 tube 3 rocket engines
1 shuts down and 2 continue to steer it then moveable in the tube
from engineering viewpoint seen that looks clumsy.

Why not use 1 engine that's moveable?
a) much cheaper
b) easier to bugfix
c) more efficient

James Heinrich 2020-12-10 01:04

[QUOTE=diep;565814]Why not use 1 engine that's moveable?[/QUOTE]Previous tests were 1-engine versions. The final version will be (I believe) a 6-engine design.

Uncwilly 2020-12-10 01:12

[QUOTE=James Heinrich;565815]Previous tests were 1-engine versions. The final version will be (I believe) a 6-engine design.[/QUOTE]But only the three that you saw today will be steerable. The other 3 will be optimized for vacuum. Having large engines causes them to be more expensive than a straight scaling would lead you to believe. Also, 1 engine with the thrust of those 3, would no be able to throttle down enough to land. With the Falcon9, they use 9 engines to launch, but only 1 during the landing. And even then they have to wait until very late to use it, otherwise the nearly empty booster would start flying up again.
More small engines allow the craft to loose 1 and still make it to orbit.

storm5510 2020-12-10 02:48

[QUOTE=Uncwilly;565811]It was supposed to land in the same orientation as it took off. It ran into low fuel pressure. The belly first fall was as planned. The flip to tail end down was as planned. It just didn't slow enough.[/QUOTE]

I watched the latter part of the video. The liftoff seemed slow. I wondered what all the engine misbehavior was about. It definitely hit the ground too hard. I have seen a few of the Falcon 9 first stage landings. Amazing stuff considering how fast it falls.

Dr Sardonicus 2020-12-10 02:50

[QUOTE=storm5510;565808]What was it that this vehicle was supposed to do? It did not turn out very well from the looks of it. :confused:[/QUOTE][quote=Elon Musk]Fuel header tank pressure was low during landing burn, causing touchdown velocity to be high & RUD[sup]†[/sup], but we got all the data we needed!

Even reaching apogee would've been great, so controlling all way to putting the crater in the right spot was epic!![/quote][sup]†[/sup][b]R[/b]apid [b]U[/b]nscheduled [b]D[/b]isassembly

:missingteeth: :missingteeth: :missingteeth:

Uncwilly 2020-12-10 02:54

I think that they had the engines throttled back to start with, because 1 engine was enough for the test hops (with a dummy load on top). Since the low pressure in the fuel tank happened, there was not enough thrust at the end to slow it down fast enough. That also likely explains the odd exhaust color. Fuel is used to cool the engines and protect it. Once you lose that, hot oxygen can attack the metal.

xilman 2020-12-10 09:26

[QUOTE=Uncwilly;565820]That also likely explains the odd exhaust color. Fuel is used to cool the engines and protect it. Once you lose that, hot oxygen can attack the metal.[/QUOTE]the colour reminded me very strongly of nitrogen dioxide.

N_2H_4 burn-off perhaps?

retina 2020-12-10 09:35

[QUOTE=storm5510;565818]I watched the latter part of the video. The liftoff seemed slow. I wondered what all the engine misbehavior was about.[/QUOTE]There were some tests that simulated engine failure. The vid shows how quickly the engines are re-gimballed to adjust for the defunct engine(s).

storm5510 2020-12-11 18:12

[QUOTE=Uncwilly;565820]I think that they had the engines throttled back to start with, because 1 engine was enough for the test hops (with a dummy load on top). [B]Since the low pressure in the fuel tank happened, there was not enough thrust at the end to slow it down fast enough.[/B] That also likely explains the odd exhaust color. Fuel is used to cool the engines and protect it. Once you lose that, hot oxygen can attack the metal.[/QUOTE]

There must be pumps to supply the engines with what they need. I would not think a lowering of tank pressure would interfere with pump operations that much, unless a negative G force was involved during the attempted landing.

A bit off-topic given the current context. The two Crew-Dragon flights had a camera inside the second stage. The engine bell was white-hot both times. Those must be made from something quite special to tolerate that much heat.

Uncwilly 2020-12-11 18:25

[QUOTE=xilman;565840]the colour reminded me very strongly of nitrogen dioxide.[/QUOTE][FONT="Arial Black"][COLOR="YellowGreen"]Cu[/COLOR][/FONT]

[QUOTE=storm5510;565952]There must be pumps to supply the engines with what they need. I would not think a lowering of tank pressure would interfere with pump operations that much, unless a negative G force was involved during the attempted landing.

A bit off-topic given the current context. The two Crew-Dragon flights had a camera inside the second stage. The engine bell was white-hot both times. Those must be made from something quite special to tolerate that much heat.[/QUOTE]The powerhead of the rocket engine has/is those pumps. If the supply line feeding those pumps does not have enough pressure, they will starve. (Pumps are designed to run a certain head pressure). The final burn was coming off the 'small' header tanks. Those are designed to be able to feed the engines during this maneuver. The tanks are pressurized with hot gas produced by the engines. Some rockets use helium to keep the tanks at pressure (a small volume of the liquid a small tank can expand to a very large volume of gas). The Star Ship is designed to use the autogenous system, because there are no helium fueling stations on the moon or Mars.

Dr Sardonicus 2021-02-03 17:30

[url=https://apnews.com/article/spacex-2nd-starship-flight-5ad6ee13518443d7a76da32e0725bc73]SpaceX's 2nd Starship test flight ends with another kaboom[/url][quote]The full-scale stainless steel rocket reached its intended altitude of 6.2 miles (10 kilometers), slightly lower than the last one. Everything seemed to be going well as the 160-foot (50-meter) Starship flipped on its side and began its descent. But it did not manage to straighten itself back up in time for a landing and slammed into the ground.

"We've just got to work on that landing a little bit," said SpaceX launch commentator John Insprucker. "Reminder - this is a test flight."[/quote]

diep 2021-02-03 18:38

[QUOTE=Dr Sardonicus;570799][url=https://apnews.com/article/spacex-2nd-starship-flight-5ad6ee13518443d7a76da32e0725bc73]SpaceX's 2nd Starship test flight ends with another kaboom[/url][/QUOTE]

I'm not a fan of humans further away than low orbit - as that's just throwing good money after bad money. (the burden it lays at the taxpayers because our technology is not so advanced yet, that burden is way way too high and it's all about some monkey surviving in space then rather than increasing the knowledge of humankind).

That said - it's tests what happens here - they're supposed to crash a lot - otherwise you clearly aren't testing everything very well!

xilman 2021-02-03 18:52

[QUOTE=diep;570801]I'm not a fan of humans further away than low orbit - as that's just throwing good money after bad money. (the burden it lays at the taxpayers because our technology is not so advanced yet, that burden is way way too high and it's all about some monkey surviving in space then rather than increasing the knowledge of humankind).[/QUOTE]It is not entirely tax payers' money.

Private enterprise already has ambitions for lunar and Martian missions and is putting their money where their mouths are. IMO, there is a very good chance of them occurring within 5-10 years.

diep 2021-02-03 19:03

[QUOTE=xilman;570802]It is not entirely tax payers' money.

Private enterprise already has ambitions for lunar and Martian missions and is putting their money where their mouths are. IMO, there is a very good chance of them occurring within 5-10 years.[/QUOTE]

Manned mission to Mars is order 10 trillion dollar - except if you want to 'throw away the people' with certainty. In short if you do not care they get killed with 99.99% certainty very quickly during the mission.

And all they would do on mars such people is sit in a bunker deep underground as going outside is too dangerous and would risk their life too much. The only advantage of having them there is that they can remote operate robots a little faster.

Why pay all those trillions of dollars if the alternative is autonomeous software with robots - which we didn't have yet - for example because CPU's and programming wasn't that advanced yet - in the 1960s?

Note that as for mars so far the only succesful landings on the Marsian soil has been done by NASA last time i checked.

There is nothing in space which privately is worth more cash than the same material is on the surface of planet earth. It's all taxpayers dollars what it is about.

Saying that some missions were 'privately paid' by Musk is also not entirely true - he got billions of subsidy cash first. So wasting a rocket with a cardboard Tesla car to 'test' some rocket out in space is not exactly privately paid either - that was tax payers dollars too.

As far as i know not even Musk, whose wealth comes close to some of the Arab oil sheikhs, posseses trillions of dollars. He's simply a businessman good in making money. Saying that he would want to pay something privately or could afford going manned to Mars privately is a nonsense story.

p.s. there is lots of nonsense stories out there in the media. Like Musk who optimistically said launching a rocket he would do for 10 million dollar. Yet in reality every mission he brings 4 astronauts to ISS, he'll catch what is it like 90 million a ticket or in short he catches over 300 million dollar - and if we add the billions of subsidy - it's right now a couple of billions a mission - which in the long run could go to 0.5 billion dollar for a single mission. Still factor 50 more than what is out there in the media.

Guess anyone can afford a ticket to the Moon?
Cheapest price i heard to go to the moon is 700 million dollar.
Yet that'll be eating babi papi pangang all the way to the moon without return ticket i guess.

Sure Jeff Bezos could. But will he?

They all want a share of those trillions of dollars if in future some president is stupid enough to sign off for a manned mission to Mars. And otherwise some dude in the EU. Not good enough to run a small ministery in Germany - good enough as EU president it seems. Yet not good enough to even buy a handful of vaccins. Some dude like that in future might sign off - who knows? They all want a chance to cash in some of those trillions!

storm5510 2021-02-04 01:05

[QUOTE=Dr Sardonicus;570799][URL="https://apnews.com/article/spacex-2nd-starship-flight-5ad6ee13518443d7a76da32e0725bc73"]SpaceX's 2nd Starship test flight ends with another kaboom[/URL][/QUOTE]

Watching this reminded me of the B&W video's of the early 1960's Atlas tests. John Glenn was present for many. He would have to ride one into orbit. I doubt having the escape tower on top brought him much comfort. I am sure he would have liked going to the moon. NASA finally allowed him to participate in a shuttle mission in 1998. He was 77 years old at the time.

LaurV 2021-02-17 16:11

Are we [URL="https://www.youtube.com/watch?v=tH2tKigOPBU"]there[/URL] yet?

retina 2021-02-17 16:35

[QUOTE=LaurV;571811]Are we [URL="https://www.youtube.com/watch?v=tH2tKigOPBU"]there[/URL] yet?[/QUOTE]Also this is interesting IMO.

[url]https://youtu.be/GhsZUZmJvaM[/url]

diep 2021-02-17 17:18

[QUOTE=LaurV;571811]Are we [URL="https://www.youtube.com/watch?v=tH2tKigOPBU"]there[/URL] yet?[/QUOTE]

Cool video. Note i'm a bit amazed he shows a thing he designed there - i design stuff like that so to speak in 1 day in CAD here - with probably far more primitive CAD as i can't afford the better CAD software...

Now some might not realize how tough it is to land on Mars as it is a total unlivable planet - yet i'm a bit amazed that they use another special vehicle to land the rover on Mars to go down from 200 km/hour to some sort of normal touchdown there.

That last thing with the rockets and some ropes to lower the rover looks like a vehicle from a science fiction series :)

Yet are they sure that lowering the rover on a rope below some rockets that give thrust upwards is the best idea?

Dr Sardonicus 2021-02-17 17:32

[QUOTE=LaurV;571811]Are we [URL="https://www.youtube.com/watch?v=tH2tKigOPBU"]there[/URL] yet?[/QUOTE]Perhaps "CRASH COURSE" was not the best choice of words...

Interesting to have an exhibit of hardware items, many of whose designs did [i]not[/i] work. That can be a real time-saver.

diep 2021-02-17 17:42

[QUOTE=Dr Sardonicus;571820]Perhaps "CRASH COURSE" was not the best choice of words...

Interesting to have an exhibit of hardware items, many of whose designs did [i]not[/i] work. That can be a real time-saver.[/QUOTE]

I would guess that's possibly secret - because other than NASA not many other nations so far managed to land a rover there...

So they show a few simple adapters and that's it.

(edit: AFAIK all other nations crashed into Mars with all missions that tried to land on the planet with rover type hardware - so we'll see whether the Chinese do better there than the amateurs of ESA - and for all those ESA, NASA and similar type governmental organisations - if you give that rover design to a team of SEAT - they'll redesign it in 3 days with half the components and a lot lighter in weight)

chalsall 2021-02-17 19:28

[QUOTE=retina;571812]Also this is interesting IMO. [url]https://youtu.be/GhsZUZmJvaM[/url][/QUOTE]

Indeed. Thanks for sharing.

Engineers tend to "thread the needle" between what is the bare minimum and what is too expensive to build.

Along with Scientists, they (IMHO) should be listened to more.

P.S. Somewhat amusing, my grammar correction AI is telling me my above should be s/be listened to more/listen more/; # Incorrect, but thanks for the advice...

firejuggler 2021-02-18 08:20

Today, we try to land a robot on Mars. With success I hope!

Uncwilly 2021-02-18 13:42

[QUOTE=firejuggler;571882]Today, we try to land a robot on Mars. With success I hope![/QUOTE]Done it before with the same basic system. This will be the USoA's 9th lander (and 5the rover) to succeed.

Dr Sardonicus 2021-02-18 14:49

[QUOTE=Uncwilly;571893]Done it before with the same basic system. This will be the USoA's 9th lander (and 5the rover) to succeed.[/QUOTE][taps knuckles on side of head] Knock on wood...

My understanding is, the Soviet Union actually achieved a "soft landing" on Mars in 1971, but the lander (Mars 3) only transmitted data for a short time (20 seconds? 45 seconds?) after landing.

retina 2021-02-18 14:51

[QUOTE=Dr Sardonicus;571902]My understanding is, the Soviet Union actually achieved a "soft landing" on Mars in 1971, but the lander (Mars 3) only transmitted data for a short time (20 seconds? 45 seconds?) after landing.[/QUOTE][url]https://en.wikipedia.org/wiki/Mars_3[/url] [quote]After 20 seconds, transmission stopped for unknown reasons.[/quote]

Uncwilly 2021-02-18 15:04

[QUOTE=Dr Sardonicus;571902]My understanding is, the Soviet Union actually achieved a "soft landing" on Mars in 1971, but the lander (Mars 3) only transmitted data for a short time (20 seconds? 45 seconds?) after landing.[/QUOTE]And there was no scientific data in that. Nor with any other non-'Merican lander. The Mars 2020 mission (aka Perseverance) is using the same method as MSL (Curiosity) to land. This time, though there is better software and more capability to avoid hazards on the way in. So the likelihood of a successful landing is much greater. And the likelihood of a landing in the center of the desired area is much better too.

LaurV 2021-02-18 18:07

[QUOTE=LaurV;571811]Are we [URL="https://www.youtube.com/watch?v=tH2tKigOPBU"]there[/URL] yet?[/QUOTE]
And, [URL="https://www.youtube.com/watch?v=gm0b_ijaYMQ"]going live[/URL] in 69 minutes.... Here is 1:05 AM, I may stay, I may not, I may stay, I may not...

masser 2021-02-18 18:12

[QUOTE=LaurV;571927]And, [URL="https://www.youtube.com/watch?v=gm0b_ijaYMQ"]going live[/URL] in 69 minutes.... Here is 1:05 AM, I may stay, I may not, I may stay, I may not...[/QUOTE]

stay! stay! stay! stay! stay!

one more cup of coffee: chug! chug! chug!

(I'd probably call it a night too; good reports will be available (or not :sad:) upon waking)

chalsall 2021-02-18 18:32

[QUOTE=masser;571928]stay! stay! stay! stay! stay![/QUOTE]

Annoyingly, I have an important meeting scheduled just when EDL occurs.

I don't do dichotic listening well (I can usually barely deal with one audio channel), but am going to give it another try shortly... :smile:

Uncwilly 2021-02-18 19:53

[QUOTE=chalsall;571930]Annoyingly, I have an important meeting scheduled just when EDL occurs.

I don't do dichotic listening well (I can usually barely deal with one audio channel), but am going to give it another try shortly... :smile:[/QUOTE]
Someone should set-up an ITTT for things like this that plays one of several tones when certain events occur. A simple beep on atmospheric interface. A low beep followed by a high beep for successful parachute deploy (a low then low would be a failure.) Then as the events tick by the first tone raises and the second tone indicates good (high) or bad (low). A triple high beep would close out a fully successful sequence.

Uncwilly 2021-02-18 21:02

1 Attachment(s)
Landing successful

pinhodecarlos 2021-02-18 21:03

Amazing!

bsquared 2021-02-18 21:04

.

:snipe:

:bow wave:

chalsall 2021-02-18 22:00

[QUOTE=Uncwilly;571937]Someone should set-up an ITTT for things like this that plays one of several tones when certain events occur. A simple beep on atmospheric interface.[/QUOTE]

It's a good thing I read that after my meeting. Or else they would have seen me fall out of my chair and ROFLMAO (out of frame)... :smile:

I did read out the important status reports of the EDL sequence during my meeting.

Almost no one found it funny... :chalsall:

Uncwilly 2021-02-18 22:16

[QUOTE=chalsall;571955]It's a good thing I read that after my meeting. Or else they would have seen me fall out of my chair and ROFLMAO (out of frame)... :smile:[/QUOTE] Why is that ROFL worthy? Having an "If This Then That" recipe that provides little audio notices for live events would be useful. An example might be the world cup. Set your favored team. When they play every time a team scores either a low tone sounds with their opponent scores or a high tone when they score. At the end of the game to beeps of the same tone tells the winner. A space launch could have a similar thing with progressing 2 tones. Election results, pick your side and get tones as results roll in. When your SO sends an SMS that they are home safe/their flight got in, what ever, a distinct tone sequence that reveals more than the "hey you got an SMS" noise. These could be useful while driving or in a meeting (a vibration pattern if the phone is on silent).

chalsall 2021-02-18 22:42

[QUOTE=Uncwilly;571957]Why is that ROFL worthy?[/QUOTE]

OK, maybe only I found it funny...

[url]https://www.youtube.com/watch?v=9kpBzUQHYtM[/url]

Dr Sardonicus 2021-02-18 23:10

It made it! :alien:

:bow wave:

:party:

LaurV 2021-02-19 03:16

Yeah!

:party:

Just seen it! (I didn't stay :sad: my eyes were already fallen into my mouth and they were looking through between the teeth...)


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