Space - The Final Frontier

[Koogie]

^^^ Great video. Inane commentary.

[MRG]

Quote:

Originally Posted by Chuckanut Here's video of the highlights of Starship SN10's flight. Including the interesting end. It did land safely, for about 8 minutes.

Time for everyone to get out. Boom![emoji6]

[Chuckanut]

SN11 gave us another interesting test flight this morning. Apparently, it had a few new issues, and after another rapid unscheduled disassembly event it landed by spreading its parts over the landing area.

[JoeWras]

Quote:

Originally Posted by Chuckanut SN11 gave us another interesting test flight this morning. Apparently, it had a few new issues, and after another rapid unscheduled disassembly event it landed by spreading its parts over the landing area.

Reminds me of watching automobile racing. As we watch the cars disintegrate, the helpful announcers explain that this is good, because it is dissipating energy away from the driver.

So I guess a landing is soft if parts are spread over the area, no?

[Chuckanut]

The Ingenuity helicopter is set for its first test flight on Sunday. The WSJ has an interesting article on Ingenuity and what it will try to do in today's paper (page A6).

Interestingly, flying a helicopter in the Martian atmosphere at ground level is like flying a helicopter at 22,000 feet here on Earth. High performance helicopters can hover at about 10,000 feet here on Earth. Ingenuity has no special scientific instruments, NASA simply wants to see if it can fly a helicopter on Mars.

The article below contains a link to the what will be the live broadcast of the flight. Video taken of and by Ingenuity probably won't be available for a few days.

https://www.businessinsider.com/watc...e-2021-4?op=1a

Good Luck and Go Baby Go!

[JoeWras]

I probably won't watch the live feed of the rocket scientists looking at their screens and either cheering or having puzzled looks on their faces.

I am very interested in the results, analysis and hopefully video once they process it over the following hours and days.

[CaptTom]

Quote:

Originally Posted by JoeWras I probably won't watch the live feed of the rocket scientists looking at their screens and either cheering or having puzzled looks on their faces. I am very interested in the results, analysis and hopefully video once they process it over the following hours and days.

I just read that the data (and maybe video?) won't be in until the wee hours of Monday morning. So maybe I'll check in when I get up.

Given the amount of planning and preparation which went into this, I suspect it'll work well. I'm sure nobody wanted their name, or their company's name, associated with that one point of failure. That's why spacecraft always seem to last longer, and work better, than the original mission specs required.

[Chuckanut]

Quote:

Originally Posted by CaptTom That's why spacecraft always seem to last longer, and work better, than the original mission specs required.

IIRC, Scotty advised young engineers in Star Fleet to never give an unpadded somewhat positive estimate. Always under promise and over deliver.

[easysurfer]

Mars helicopter flight delayed. Darn, was looking forward ... (probably needs a person to tap the helicopter's side as a kickstart like the old TV sets ).

Quote:

You'll have to wait a little while longer to see NASA's Mars helicopter in action. The agency has delayed Ingenuity's first flight to "no earlier than" April 14th after a test on April 9th went awry. The high-speed spin test finished prematurely after a watchdog timer (meant to catch technical issues) expired while transitioning the helicopter to its flight mode. NASA stressed that Ingenuity was "safe and healthy," and that it was reviewing telemetry from the vehicle to both understand what happened and determine when the first flight might occur.

https://news.yahoo.com/nasa-ingenuit...184140652.html

[Walt34]

This flight is also being followed closely by radio control modelers on those forums. This is of course the Ultimate Radio Control Aircraft in those circles.

[CaptTom]

Quote:

Originally Posted by CaptTom Given the amount of planning and preparation which went into this, I suspect it'll work well.

Quote:

Originally Posted by easysurfer Mars helicopter flight delayed.

Darn! I jinxed it! Sorry everybody.

[JoeWras]

Well, the watchdog timer is really not the best of news. I suspect this may take them a little time, perhaps weeks. They may also scale back the testing progression or add more simple tests first than were planned. This is just my gut feel.

The good news is they went slow to exactly find this kind of thing. The bad news is watchdogs are never expected.

As a 30+ year firmware engineer, I'm way too familiar with the concept. I'll try to explain as simple as I can.

Custom hardware like this doesn't run windows, instead it usually runs a simple command loop. The code is constantly looping, waiting and executing commands. In that loop, a timer is set. This timer should never expire because it gets reset each loop. If it expires, it triggers an emergency interrupt that puts the device into a safe mode.

All the code that runs should either: a) Run so fast the timer won't expire, or b) "pet the dog" (reset the timer) when it knows it has to run longer.

Since this didn't happen, it means that the code either lost its mind and went into a loop, or some hardware got stuck while the code was waiting for an absolutely guaranteed result from that hardware that failed its guarantee.

They should be able to determine where it went bad. Let's hope it was a typical error condition badly programmed (doubtful) because that can be fixed. I'm betting instead that some hardware is behaving badly. Still that doesn't mean all is lost, but it may mean some re-programming around that hardware.

This is hard to analyze and reprogram when the device is sitting on your desk. It is much harder when the device is light-minutes away by each command.

I'm optimistic, though. Just not optimistic for a flight very soon.

[Chuckanut]

Quote:

Originally Posted by CaptTom Darn! I jinxed it! Sorry everybody.

Twenty lashes with a wet noodle!

[Gumby]

Quote:

Originally Posted by JoeWras Well, the watchdog timer is really not the best of news. I suspect this may take them a little time, perhaps weeks. They may also scale back the testing progression or add more simple tests first than were planned. This is just my gut feel. The good news is they went slow to exactly find this kind of thing. The bad news is watchdogs are never expected. As a 30+ year firmware engineer, I'm way too familiar with the concept. I'll try to explain as simple as I can. Custom hardware like this doesn't run windows, instead it usually runs a simple command loop. The code is constantly looping, waiting and executing commands. In that loop, a timer is set. This timer should never expire because it gets reset each loop. If it expires, it triggers an emergency interrupt that puts the device into a safe mode. All the code that runs should either: a) Run so fast the timer won't expire, or b) "pet the dog" (reset the timer) when it knows it has to run longer. Since this didn't happen, it means that the code either lost its mind and went into a loop, or some hardware got stuck while the code was waiting for an absolutely guaranteed result from that hardware that failed its guarantee. They should be able to determine where it went bad. Let's hope it was a typical error condition badly programmed (doubtful) because that can be fixed. I'm betting instead that some hardware is behaving badly. Still that doesn't mean all is lost, but it may mean some re-programming around that hardware. This is hard to analyze and reprogram when the device is sitting on your desk. It is much harder when the device is light-minutes away by each command. I'm optimistic, though. Just not optimistic for a flight very soon.

Thank you for that explanation. I had no idea what a watchdog timer was, and I'll bet I'm not the only one.

[Yoheadden]

Asteroid 2021 GW4 was discovered on April 8, 2021 using the 59 inches (1.5 meter) telescope of the Catalina Sky Survey at Mt. Lemmon, Arizona.
Anyone hear about this one ?


Bottom line: A small asteroid designated 2021 GW4 will pass extremely close to Earth on Monday, April 12, 2021. It’ll pass just 12,313 miles (19,816 km) from Earth’s surface, which is about 5% the Earth-moon distance. Amateur astronomers using telescopes can see it shortly before closest approach passing the galaxy Messier 95 on the night of Sunday, April 11.

[Gumby]

Quote:

Originally Posted by Yoheadden Asteroid 2021 GW4 was discovered on April 8, 2021 using the 59 inches (1.5 meter) telescope of the Catalina Sky Survey at Mt. Lemmon, Arizona. Anyone hear about this one ? Bottom line: A small asteroid designated 2021 GW4 will pass extremely close to Earth on Monday, April 12, 2021. It’ll pass just 12,313 miles (19,816 km) from Earth’s surface, which is about 5% the Earth-moon distance. Amateur astronomers using telescopes can see it shortly before closest approach passing the galaxy Messier 95 on the night of Sunday, April 11.

Close enough to theoretically hit a geosynchronous satellite, which are at about 22k miles above the surface.

[Koogie]

"""The small asteroid has been designated as 2021 GW4. It is estimated to be about 16 feet (5 meters) in diameter."""

Impressed they could find something that small moving at that speed (+/-30.000 kph)

[Walt34]

Quote:

Originally Posted by Gumby Thank you for that explanation. I had no idea what a watchdog timer was, and I'll bet I'm not the only one.

+1

That makes at least two of us.

[JoeWras]

Quote:

Originally Posted by Walt34 +1 That makes at least two of us.

You are welcome, folks. In my last Megacorp, I originally hated debugging watchdogs because they could be mysteriously difficult. As I gained confidence over the years, I actually enjoyed the challenge.

I thought about one more thing on Ingenuity. There's a possibility they intentionally call a watchdog event when anything goes wrong, because this is the well known "safe mode" path. I saw this kind of programming once eons ago. Given that this space hardened code has to be tight, they may do it this way. The event may point directly to a known error condition that is easy to fix. Let's hope for this.

I'll give a hypothetical. Say they command the blades to be at 6 degrees, and do not expect RPMs to go over 5k at this pitch. If the RPMs go over, perhaps they just intentionally watchdog. The fix may be to set the pitch at 8 degrees. It would be great if this is the kind of issue they find. Easy fix.

[Boho]

Quote:

Originally Posted by JoeWras I'll give a hypothetical. Say they command the blades to be at 6 degrees, and do not expect RPMs to go over 5k at this pitch. If the RPMs go over, perhaps they just intentionally watchdog. The fix may be to set the pitch at 8 degrees. It would be great if this is the kind of issue they find. Easy fix.

It's also easy to communicate that along with the notice of the watchdog event. It seems like we would have known by now if it were that simple.

The helicopter doesn't seem robust at all. It sounds like there's absolutely no way to manipulate anything to correct its position if it lands badly, and that's the expected mode of failure at the end if its life. With the watchdog event, something may be a tiny bit off with no way to fix it.