LIVE: Launching astronauts from US soil to ISS for first time in last 9 years - Page 1
Forum section: electronics / general

author: wraper
author_rank: Unknown
timestamp: May 30, 2020, 04:07:40 pm
content: Second attempt due to bad weather scrub last Wednesday:

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 30, 2020, 04:38:25 pm
content: I hope Mr. Dave is online to. He gave us interesting Information.-->https://www.eevblog.com/forum/chat/downlink-freq-for-the-today-space-flight/Does anyone here try to receive Stuff from the Aircraft?

author: rdl
author_rank: Super Contributor
timestamp: May 30, 2020, 05:07:18 pm
content: The weather is still iffy, they just said estimated odds for launch are 50-50. Jim Bridenstein said something like, it's May in Florida - we have to try every chance we get because the next opportunity will probably be no better.The video feed showing the inside of the Dragon looks truly futuristic.

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 30, 2020, 05:16:22 pm
content: Will Mr. Dave do a Stream today to?

author: wraper
author_rank: Unknown
timestamp: May 30, 2020, 07:14:57 pm
content: 8 minutes left. Looks it's a go.

author: Shock
author_rank: Super Contributor
timestamp: May 30, 2020, 07:40:44 pm
content: Success! 19 hours to the ISS.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 30, 2020, 07:51:17 pm
content: That was a neat and uneventful launch, just like you'd want them to be. As posted in the TEA thread I saw what seems to be a 87V used during the door closing procedure. Looks like they were using it in the ohms range or continuity mode. I'm quite curious what they were doing, as it seems part of the regular procedure. Maybe it's used to check the door is properly sealed somehow.

author: dr.diesel
author_rank: Super Contributor
timestamp: May 30, 2020, 07:56:52 pm
content: ^ Those guys need renamed to SpaceX Ninjas!

author: Shock
author_rank: Super Contributor
timestamp: May 30, 2020, 08:00:16 pm
content: Purely speculation but likely a manual check to see if the locking mechanism is fully engaged. I've not seen much on the design but they exit to the ISS via the nose so that is essentially a one way door.

author: nctnico
author_rank: Super Contributor
timestamp: May 30, 2020, 08:01:05 pm
content: I'm not liking the Nintendo-look of the inside of the new space ship.Where did all the buttons go?

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 30, 2020, 08:11:20 pm
content: Quote from: Shock on May 30, 2020, 08:00:16 pmThat's my guess too, but I'd like to know how they do it exactly. Maybe some resistance measurement to infer how well the mechanism is engaged?

author: Shock
author_rank: Super Contributor
timestamp: May 30, 2020, 08:31:06 pm
content: Could possibly be also the emergency exit release now I've watched it again and them faffing with the handle. So it's probably something like an air bag system for blowing the door open or breaking the seal, either way resistance is a good way to check you have a good electrical connection or that a mechanism is fully connected without powering it up fully.

author: Gyro
author_rank: Super Contributor
timestamp: May 30, 2020, 08:49:35 pm
content: In the coverage on Wednesday, they said they were checking for pressure bleed - some kind of resistive pressure sensor?

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 30, 2020, 08:55:28 pm
content: Quote from: Gyro on May 30, 2020, 08:49:35 pmPossibly, but I'd wager those would be accessible from inside the vehicle and included in the telemetry. This looks like something which is checked once.

author: Howardlong
author_rank: Super Contributor
timestamp: May 30, 2020, 10:07:52 pm
content: Quote from: nctnico on May 30, 2020, 08:01:05 pmI was also thinking the touch screens were an interesting update, I mean it's not like we've ever had a touch gesture misinterpreted!

author: eti
author_rank: Super Contributor
timestamp: May 31, 2020, 12:10:24 am
content: It was superb, but I will just say this:~ Those space suits look ridiculous - too "trendy".~ I wish Elon-"I am gonna rule the world, save the planet and then move everyone to the moon"-Musk would butt out, and leave space to REAL ENGINEERS from NASA; having his cringey company stepping in and funding stuff just seems like one GIANT, perpetual commercial marketing stunt & money grab. His cars are SHITE, they're never going to take over, and I find the whole thing very weird, and it doesn't sit well.

author: eti
author_rank: Super Contributor
timestamp: May 31, 2020, 12:15:45 am
content: Quote from: nctnico on May 30, 2020, 08:01:05 pmIt's silly, but then, society is brainwashed because everyone's convinced themselves that touch screens HAVE to be on EVERYTHING, and because they're everywhere else too...I can hear this fictional narrator in my head, saying "But this is the science fiction we'd dreamed of YEARS ago, and we hoped one day it would happen - we've MADE it happen, it HAS to happen, and everything HAS to be touch screen because it was our dream" kinda narrative - like it's SO forced and contrived - they HAVE to have touch screen EVERYTHING "just because..." and because some kids had a sci fi fantasy 50 years ago, then those kids grew up, and forced their fantasy to become reality "JUST BECAUSE"People are idiots, didn't you realise?It's likely because Mr Musk is on the scene, and has forced giant iPad-esque touch panels into Teslas... WHY? Who knows! Because it's ... "futuristic" and looks "kewl" - and along with idiotic gullwing doors that serve no purpose except to SCREEEAAAAAAM "FUTURE!!!! FUTURISTIC!!!" I bet you the cognitive load with those Tesla touch panels is AWFUL! When you're driving a car, you want a PHYSICAL CONTROL - buttons don't freeze and crash, softwaredoes!Ain't NO WAY, ever, these kiddy toy cars are "the foooootcha!" OR taking over anything, it's all a pipe dream from sci fi nerds and Tesla cheerleaders. NO WAY.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 31, 2020, 12:38:27 am
content: Quote from: eti on May 31, 2020, 12:15:45 amAre you trying to single handedly prove people are idiots?

author: rdl
author_rank: Super Contributor
timestamp: May 31, 2020, 12:43:19 am
content: I read somewhere that the concept for the look of the suits was done by a Hollywood costume designer.Starliner has a much more traditional interior design than the Dragon but both are intended to be flown completely automated, so the controls are somewhat redundant anyway.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 31, 2020, 12:52:47 am
content: Quote from: rdl on May 31, 2020, 12:43:19 amAs far as I understand the craft can be fully controlled from the capsule, even though most spacecraft have historically been flown mostly automatically. In almost all cases crew are simply meaty cargo. Either way, there's little doubt extensive testing was done to ensure functionality of any newly introduced features. Any failure due to a bad choice could effectively end SpaceX at this stage.

author: wraper
author_rank: Unknown
timestamp: May 31, 2020, 12:54:18 am
content: Quote from: eti on May 31, 2020, 12:15:45 amAt least in case with astronauts gullwing doors make them way easier to enter/leave while wearing constraining spacesuits. Fashion thing but in this case quite usable feature.Also do you think this is more practical than 3 touchscreens and a few buttons? If it does the job well, put something that takes minimum space and weight which are quite limited resources in space capsule.

author: Shock
author_rank: Super Contributor
timestamp: May 31, 2020, 12:54:37 am
content: It has to be made before people realize if they need it or not. Certain technologies have downsides, VR has been around since the 80s and it's still a take it or leave it technology. Looks like lithium battery powered cars may not be around in the future. Touch screens are good for displaying and sorting through information but I don't think they will replace manual controls any time soon.

author: nctnico
author_rank: Super Contributor
timestamp: May 31, 2020, 12:56:58 am
content: Quote from: rdl on May 31, 2020, 12:43:19 amFound an article on the controls:https://www.theverge.com/2020/5/30/21275753/nasa-spacex-astronauts-fly-crew-dragon-touchscreen-controlsI'm still puzzled on how they are going to operate those touch screens in high-G (emergency) situations. Fighter jets typically have force sensor sticks for which you don't need to lift or move your arm at all.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 31, 2020, 12:57:39 am
content: Quote from: wraper on May 31, 2020, 12:54:18 amThe Space Shuttle was a not too great compromise in many ways. It should never have existed from an engineering point of view but politics and large amounts of money pumped into facilities across the nation ensured it did anyway.

author: Shock
author_rank: Super Contributor
timestamp: May 31, 2020, 01:06:24 am
content: The Space Shuttle is 70s tech rolled out into the 80s for specific tasks. It's not like they said hey lets make this complicated as we can, back then everything needed a button, switch or knob. 135 missions according to NASA.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 31, 2020, 01:59:51 am
content: Quote from: Shock on May 31, 2020, 01:06:24 amIt wasn't just a product of its age. It was as much a political vehicle as it was a functional one and it shows.https://www.technologyreview.com/2011/07/06/193194/was-the-space-shuttle-a-mistake/

author: hendorog
author_rank: Super Contributor
timestamp: May 31, 2020, 02:13:54 am
content: Quote from: nctnico on May 31, 2020, 12:56:58 amI was thinking the same thing. It's such an obvious problem with touchscreens that they must have mitigated it somehow.

author: eti
author_rank: Super Contributor
timestamp: May 31, 2020, 02:15:52 am
content: Quote from: Mr. Scram on May 31, 2020, 12:38:27 amNo, that would be a waste of energy and time; they do just fine proving it all on their own.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 31, 2020, 03:02:50 am
content: Quote from: eti on May 31, 2020, 02:15:52 amToo late, you already did.

author: ChunkyPastaSauce
author_rank: Unknown
timestamp: May 31, 2020, 03:46:19 am
content: Quote from: wraper on May 31, 2020, 12:54:18 amBetter comparison would be another capsule for ISS missions, since the functionality is about the same. The obvious one being Soyuz capsule, the control dash area happens to be about the same size and looks more realistic to condense.Soyuz

author: jogri
author_rank: Frequent Contributor
timestamp: May 31, 2020, 11:01:43 am
content: Quote from: nctnico on May 31, 2020, 12:56:58 amWhat exactly is an high-G manoeuvre for you? If i recall correctly the crew is suspected to ~2.5G shortly before Max-Q, and right now you have to fighter pilots sitting in the capsule, they probably won't bat an eye (okay, that's going to change with regular missions). They would probably see ~6-7 G on a inflight abort at Max-Q (someone did the math for the ground abort and calculated 3.5G for that, plus the ~2.5G during normal flight), but it would require superhuman reactions to control the capsule anyway, so it is done by the flight computer ->no interactions required.The only situation where they could be required to use the touchscreens at high-G would be during reentry, but if the capsule is similar to the Souyz they would experience under 4G (and i am not sure if this G-number is reached while breaking or if it is the negative G they would feel when the chutes deployed).It's not like the old Gemini/Mercury systems that reached 7G on both stages, you probably just had to pray that the rest of the rocket would function if something broke during launch.

author: nctnico
author_rank: Super Contributor
timestamp: May 31, 2020, 12:00:44 pm
content: IIRC one of the Gemini missions got a stuck manoeuvring thruster putting the space craft into a wild spin. Current technology is likely much better but things still can go wrong.

author: dr.diesel
author_rank: Super Contributor
timestamp: May 31, 2020, 12:10:39 pm
content: Anybody know what OS is running on the Dragon touchscreens?SpaceX uses a lot of Linux from what I've heard, but the bottom menu row does look a bit custom Winish.

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 31, 2020, 02:07:34 pm
content: Well I guess the use some highly customised system who will reset them self in the case of a OS Crash.

author: tom66
author_rank: Super Contributor
timestamp: May 31, 2020, 02:08:48 pm
content: If SpaceX were using Windows on those systems I'd be shocked. It's almost certainly a custom Linux or possibly an RTOS for reliability if qualifying Linux was seen as too difficult.

author: nctnico
author_rank: Super Contributor
timestamp: May 31, 2020, 02:50:53 pm
content: Quote from: Lord of nothing on May 31, 2020, 02:07:34 pmI doubt they run Linux and I doubt they run an OS they wrote from scratch. More likely it is a mission critical OS; probably very similar to what Tesla is using in their cars.

author: dr.diesel
author_rank: Super Contributor
timestamp: May 31, 2020, 02:54:33 pm
content: Quote from: nctnico on May 31, 2020, 02:50:53 pmPretty sure the cars run Linux.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 31, 2020, 03:04:59 pm
content: Tesla is using a custom Linux-based OS, while a few other manufacturers use QNX.AFAIK, SpaceX also uses a custom Linux-based OS. I don't know if there are any major differences between the two, like for instance the kernel version and set of patches.https://www.zdnet.com/article/linux-is-under-your-hood/https://www.rankred.com/what-hardware-software-does-spacex-use-to-power-its-rockets/

author: rdl
author_rank: Super Contributor
timestamp: May 31, 2020, 03:08:38 pm
content: Docking is complete. Commander Chris Cassidy looks overworked getting ready to open the hatch. I bet he's looking forward to having some help onboard.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 31, 2020, 03:28:57 pm
content: I missed the docking sequence itself, I'll have to see that on a replay.Amazing job anyway.

author: tom66
author_rank: Super Contributor
timestamp: May 31, 2020, 04:03:58 pm
content: Quote from: nctnico on May 31, 2020, 02:50:53 pmTesla runs Linux in their cars for their touchscreen and instrument cluster (specifically, at least in the original Model S, it was a heavily stripped Ubuntu distribution.)Not sure about the ECUs but likely an RTOS or baremetal, depends on what the ECU controls.

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 31, 2020, 04:24:36 pm
content: sry I was busy I just saw them docking what did the do now?Are the out of the Aircraft?

author: jogri
author_rank: Frequent Contributor
timestamp: May 31, 2020, 06:28:54 pm
content: Yeah, they entered the ISS about an hour ago

author: nctnico
author_rank: Super Contributor
timestamp: May 31, 2020, 06:54:11 pm
content: Quote from: dr.diesel on May 31, 2020, 02:54:33 pmProbably for the infotainment system but it would surprise me if they run Linux on the computers which do the auto-pilot, safety features and engine control. That was what I was aiming at (to be clear).

author: dr.diesel
author_rank: Super Contributor
timestamp: May 31, 2020, 07:05:36 pm
content: Quote from: nctnico on May 31, 2020, 06:54:11 pmAuto Pilot is a really good question, would love to read more about that specifically.

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 31, 2020, 07:08:16 pm
content: Quote from: nctnico on May 31, 2020, 06:54:11 pmYeah. But the OS question started with the question: "Anybody know what OS is running on the Dragon touchscreens?", so it was sort of obvious subsequent replies were dealing with that: the OS used for all the UI systems.As for all the other subsystems, probably hundreds of them, sure most of them are unlikely to run on Linux. And I also doubt they all run on the same OS. There are probably baremetal subsystems, others on RTOSs, etc.

author: Shock
author_rank: Super Contributor
timestamp: May 31, 2020, 08:26:43 pm
content: For those who missed the docking rewind this stream.

author: IDEngineer
author_rank: Super Contributor
timestamp: June 01, 2020, 07:14:00 am
content: Found today that SpaceX writes their code in C++, their screens in JavaScript, the OS is Linux, and the platform is PowerPC. They do not use rad-hard components but instead shield at the modular level.

author: Mr. Scram
author_rank: Super Contributor
timestamp: June 01, 2020, 10:23:53 pm
content: Quote from: IDEngineer on June 01, 2020, 07:14:00 amThey also use ridiculous amounts of redundancy. Almost every CPU is tripled and the set uses majority voting. There are many, many CPUs aboard for all kinds of subsystems.

author: IDEngineer
author_rank: Super Contributor
timestamp: June 02, 2020, 06:56:23 pm
content: Quote from: Mr. Scram on June 01, 2020, 10:23:53 pmThat's very common. Even the Shuttle had such redundancy. IIRC, it had five computers, three of which were "live" at any one time, with one auto-backup and I can't remember when the fifth came into play. On the original launch in 1980(?) one shut down and a backup kicked in. Then a SECOND one shut down. I remember John Young saying his knees got a little weak at that point. But it all turned out fine... it wasn't CPU's that cost us two Shuttles and two groups of astronauts.

author: 0culus
author_rank: Super Contributor
timestamp: June 02, 2020, 07:01:32 pm
content: Quote from: IDEngineer on June 02, 2020, 06:56:23 pmIIRC the final computer ran software independently developed from the primary ones.https://history.nasa.gov/computers/Ch4-3.html

author: IDEngineer
author_rank: Super Contributor
timestamp: June 02, 2020, 07:08:41 pm
content: Quote from: 0culus on June 02, 2020, 07:01:32 pmThat's what I thought I remembered, but wasn't sure so I didn't want to say so.I'd be tempted to specify things at the MODULAR level and have separately developed hardware too, but rad-hard stuff isn't exactly commonplace. SpaceX's approach of hardening the enclosure is the better solution IMO because it affords such flexibility.

author: dr.diesel
author_rank: Super Contributor
timestamp: June 04, 2020, 12:00:13 pm
content: During the Starlink launch last night the host mentioned the SpaceX Software Team will be hosing a Q&A on Reddit in the next couple weeks. Might be a great opportunity for further info on OS/Touchscreens etc.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: June 04, 2020, 05:49:56 pm
content: Quote from: eti on May 31, 2020, 12:15:45 amTesla owner here. I find the large touchscreen panel to be quite easy to use and it gives me much more information while driving than any dashboard on previous vehicles I've driven. It's never crashed or frozen on me even under extreme conditions (temperatures <0C and >45C).

author: rrinker
author_rank: Super Contributor
timestamp: June 04, 2020, 06:11:01 pm
content: Notice also the Crew Dragon has a stick, and there are also buttons for certain functions on the arm rest, where they would be relatively easy to hit while under high G loads. And also notice that the right-hand seat has the buttons on the left side, and the left seat has the buttons on the right armrest. So either person can access the buttons on the other person's seat. This is most definitely not something that was rushed through, the details have been well thought out.

author: Mr. Scram
author_rank: Super Contributor
timestamp: June 04, 2020, 08:22:53 pm
content: Quote from: IDEngineer on June 02, 2020, 06:56:23 pmThose were the main computers, not all the subsystems. There are crazy amounts of powerful processors in SpaceX hardware. SpaceX also uses commercial grade computer hardware and trusts the redundancy.

author: Mr. Scram
author_rank: Super Contributor
timestamp: June 05, 2020, 06:15:10 pm
content: Last time I didn't have time to go into detail, but it's pretty interesting. Below is a quote without any sources, but it's consistent with what we've heard elsewhere. It's essentially COTS hardware made redundant to a somewhat ridiculous degree. Rad hardening isn't wholly necessary for short orbital hops.QuoteApparently they use LabView for the ground based stuff:Quotehttps://space.stackexchange.com/questions/9243/what-computer-and-software-is-used-by-the-falcon-9

author: rdl
author_rank: Super Contributor
timestamp: June 05, 2020, 07:58:35 pm
content: QuoteWow, so Dragon 2 displays are basically using a web browser.(if that quote is correct)

author: tom66
author_rank: Super Contributor
timestamp: June 05, 2020, 09:06:08 pm
content: I wonder how much validation you'd have to go through to prove that Chromium is stable when running a JS web app for crucial flight information displays.I've managed to crash it pretty easily doing fairly normal things.

author: dr.diesel
author_rank: Super Contributor
timestamp: June 05, 2020, 11:06:26 pm
content: Quote from: rdl on June 05, 2020, 07:58:35 pmIf optimized and debugged for that particular set of functions, reliability might not be an issue.

author: dr.diesel
author_rank: Super Contributor
timestamp: June 07, 2020, 01:05:51 am
content: Reddit answers:https://www.reddit.com/r/spacex/comments/gxb7j1/we_are_the_spacex_software_team_ask_us_anything/

author: StillTrying
author_rank: Super Contributor
timestamp: August 02, 2020, 06:59:23 pm
content: How come we heard a splash the moment it touched the water when the TV camera is 3 miles away.https://www.cnet.com/news/spacex-splashdown-smoothly-delivers-nasa-astronauts-back-to-earth

author: paulca
author_rank: Super Contributor
timestamp: August 02, 2020, 07:38:15 pm
content: Quote from: StillTrying on August 02, 2020, 06:59:23 pmEm... I checked the SpaceX live stream and on it too is the splash at touch down. WTF?

author: SilverSolder
author_rank: Super Contributor
timestamp: August 02, 2020, 07:44:18 pm
content: Quote from: StillTrying on August 02, 2020, 06:59:23 pmFake news... should be used to it by now!

author: Monkeh
author_rank: Super Contributor
timestamp: August 02, 2020, 07:51:07 pm
content: Quote from: paulca on August 02, 2020, 07:38:15 pmBecause that wasn't a splash, it was the room mic being unmuted so you could hear applause.

author: paulca
author_rank: Super Contributor
timestamp: August 02, 2020, 08:19:13 pm
content: I think it was played on the control room PA by someone.

author: StillTrying
author_rank: Super Contributor
timestamp: August 02, 2020, 08:20:22 pm
content: "Because that wasn't a splash, it was the room mic being unmuted so you could hear applause."I've re-wound skynews and watched it 6 times, it definitely sounds like a splash to me!There's a boom 30 sec after the splash, = ~4.8 miles. 5.8 miles.The 50 years old recovery method is definitely not as neat as a shuttle landing.

author: chris_leyson
author_rank: Super Contributor
timestamp: August 02, 2020, 10:09:50 pm
content: Nothing wrong with touchscreens if you build them to meet or exceed avionics and space qualifications. I think wraper summed it up with the shuttle flight deck photoQuoteAlso nothing wrong with a web browser HMI, they work well and if the hardware fails over for whatever reason you've still got a backup Ipad or two. The flight sofware and the Draco thrusters worked flawlessly to autonomously fly the Dragon capsule back to earth and get Doug Hurley and Bob Behnken home safely.SpaceX have renegotiated their contract with NASA to reuse the DM-2 capsule on the first operational Crew Dragon mission due to launch in September. Whereas other human space flight vendors can't even get their flight software right.