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alfadriver (Forum Supporter)
alfadriver (Forum Supporter) MegaDork
6/1/20 12:56 p.m.

Here's an article about the guidance compueter https://history.nasa.gov/computers/Ch2-5.htm

Anyway, SpaceX gets a lot of weight advantage due to technology- and more in computers, but also in 3D printing.  IMHO, a good example of the 3D pringing is the rockets that are on the Dragon Module.  Which means they have large thrusters on the capsule oall the time, and can use them any time.

Good for them.  And given the progress, I would wonder if Boeing is taking advantage of that or not.

tuna55 (Forum Supporter)
tuna55 (Forum Supporter) MegaDork
6/1/20 12:56 p.m.
alfadriver (Forum Supporter) said:

In reply to tuna55 (Forum Supporter) :

The only other real clean sheet on their own, that I can think of quickly is Tesla.  

Which actually makes me sad for Boeing.  What Tesla said about the auto industry is actually true about the space industry.  And in the context of where I work, Alan Mulally turned out to be a pretty big player- good for us, bad for Boeing that he didn't get the gig.  If he did for Boeing what he did for us, I don't see the disasters happening, and they may have even won the race to ISS.

Interesting tangent to consider.

(I'm sure other clean sheet updates are out there- just that it's one that I relate to)

I meant clean sheet for space travel. Have the Russians been recycling the same designs forever? I sort of expect so.

 

yeah, Mulally saved F for sure.

Keith Tanner
Keith Tanner MegaDork
6/1/20 12:57 p.m.

There are lots of good articles out there about how Boeing has a fundamental culture problem. It wouldn't be a quick or easy ship to steer on to a new course. And it would be viewed as a risky choice, just look at how much money is being poured into company via the SLS contract. SLS vs Falcon is a really interesting comparison, the SLS was supposed to be built on proven technology to control costs. For example, it was to use existing Shuttle engines. Somehow, those engines cost about as much as a Falcon Heavy launch...EACH.

There are a number of mostly clean sheet designs in space right now. Rocket Lab is probably the most successful after SpaceX, but they're a little more traditional in how they're operating. Virgin Orbit is also revisiting some techniques that haven't been used for a while.

And yes, I believe the Russian technology is old and static - but also very reliable. Nothing fundamentally wrong with it other than it's getting more expensive and it's under control of a country that may or may not be our friends.

Keith Tanner
Keith Tanner MegaDork
6/1/20 1:32 p.m.
alfadriver (Forum Supporter) said:

In reply to Keith Tanner :

WRT the computers- I would wager that the Dragon computers systems are lighter than the memory from the Landing Module.  They are hard wire copper modules....  Replacing just that with modern memory of a modern computer would have save millions in fuel.

A quick google search says that it cost $1.5M/lb to the moon, and another thread has the guidance computer at 70lb.  

(I'm not sure why I can't paste in a reply, kind of annoying)

Actually, you can't just jam normal computer memory into a spacecraft. The rope memory in the guidance computer was a pretty clever and robust solution.

Yes, modern computers can be lighter and faster - but given the mass of everything on Apollo, the computers were not an enormous part of it. I would call it evolutionary and not revolutionary. I think the more integrated and iterative design process is a bigger factor. Remember that Dragon has been flying for about the length of the entire Apollo program!

bobzilla
bobzilla MegaDork
6/1/20 1:55 p.m.

In reply to Keith Tanner :

While they weren't enormous, 70lbs in memory and 35 lbs in 2 displays and keyboards is a lot of weight to lug around to do the rudimentary functions they were tasked with in comparison to modern tech. I'd love to see an alternate reality where someone takes their iphone 11 back to 1965 nasa for them to reverse engineer it. 

alfadriver (Forum Supporter)
alfadriver (Forum Supporter) MegaDork
6/1/20 3:15 p.m.
bobzilla said:

In reply to Keith Tanner :

While they weren't enormous, 70lbs in memory and 35 lbs in 2 displays and keyboards is a lot of weight to lug around to do the rudimentary functions they were tasked with in comparison to modern tech. I'd love to see an alternate reality where someone takes their iphone 11 back to 1965 nasa for them to reverse engineer it. 

And every single pound mattered.  That's more my point.  70lb is enormous- it's half a third passenger.  Not to the take off weight of the entire beast, but the take to the moon and back with the fuel available, it's a lot.  And a lot of that is in the woven memory.  Change that one aspect to the lander to modern weights, and that saves a bunch of take off fuel.

Keith Tanner
Keith Tanner MegaDork
6/1/20 3:18 p.m.

I am not expressing myself well, obviously.  Is lighter better? Hell yes. Is saving "half a passenger" in computer weight a game changer? No, not even close. That 105 lbs (computer plus screens) represents 0.3% of the weight of the LEM (hardware plus propellant).

The savings in weight on switches, knobs and individual displays may actually be greater, especially with the development of FETs in place of mechanical relays. That should also increase reliability - remember the problem with a piece of loose metal in the Abort switch in zero g in one of the landings?

alfadriver (Forum Supporter)
alfadriver (Forum Supporter) MegaDork
6/1/20 3:34 p.m.

So someone has to remember this thread in 120 days.  When they are scheduled to come back....

bobzilla
bobzilla MegaDork
6/1/20 3:49 p.m.
Keith Tanner said:

I am not expressing myself well, obviously.  Is lighter better? Hell yes. Is saving "half a passenger" in computer weight a game changer? No, not even close. That 105 lbs (computer plus screens) represents 0.3% of the weight of the LEM (hardware plus propellant).

The savings in weight on switches, knobs and individual displays may actually be greater, especially with the development of FETs in place of mechanical relays. That should also increase reliability - remember the problem with a piece of loose metal in the Abort switch in zero g in one of the landings?

I get where you're coming from. By itself, its cool but not a deal breaker. But combine all the modern stuff of today and how much would hte modern equivalent of the LEM and CM weigh today? How many people.stuff/things could go now compared to then. 

aircooled
aircooled MegaDork
6/1/20 4:49 p.m.

I know a guy who worked at Grumman (Long Island) in the day, and worked on the LEM (the base plate above the accent motor was some of his work).  There, as noted, was always a HUGE weight / numbers game going one.  A very small amount of weight at the top of the rocket (anything going to the moon) translated to a LOT of needed fuel / thrust.  Of course with the LEM, about half of it had to come back off the moon.  Not sure if weight was a huge deal there though.  It doesn't take too much to get into orbit from the moons surface.

He said on one of the LEMs, one of the windows broke.  The amount of effort to clean every tiny particles out (you don't want glass shards floating around in zero g) was pretty extreme.

David S. Wallens
David S. Wallens Editorial Director
6/1/20 11:13 p.m.

FWIW, we saw the launch--well, two one-second bits of it due to cloud cover. Still, always awe-inspiring. It's the rumble, too, that you need to experience. 

alfadriver (Forum Supporter)
alfadriver (Forum Supporter) MegaDork
6/2/20 6:08 a.m.
David S. Wallens said:

FWIW, we saw the launch--well, two one-second bits of it due to cloud cover. Still, always awe-inspiring. It's the rumble, too, that you need to experience. 

From your home or nearby?  

I keep trying to have a cuise roughly when there's a launch- but that's so on and off that it's almost impossible.  

tuna55
tuna55 MegaDork
6/2/20 7:29 a.m.
alfadriver (Forum Supporter) said:
David S. Wallens said:

FWIW, we saw the launch--well, two one-second bits of it due to cloud cover. Still, always awe-inspiring. It's the rumble, too, that you need to experience. 

From your home or nearby?  

I keep trying to have a cuise roughly when there's a launch- but that's so on and off that it's almost impossible.  

We brought our whole family down to Florida to see a launch in the spring.

 

Instead they delayed it and we all got the flu. Also I got the van stuck in the sand on a side road.

JesseWolfe
JesseWolfe Reader
6/2/20 8:26 a.m.

My family and I planned a summer vacation last July around a Falcon 9 launch.  Sadly it was weather delayed the 1 day we had in Port Canaveral, and when it did launch 3 days later, it was a t-minus 10 minutes to launch and we were in Tampa.

JesseWolfe
JesseWolfe Reader
6/2/20 8:30 a.m.

By the way, for the science geeks, here's a good video on the science and cost effectiveness of stainless steel vs composites in rockets.

 

https://youtu.be/LogE40_wR9k

alfadriver (Forum Supporter)
alfadriver (Forum Supporter) MegaDork
6/2/20 9:00 a.m.
tuna55 said:
alfadriver (Forum Supporter) said:
David S. Wallens said:

FWIW, we saw the launch--well, two one-second bits of it due to cloud cover. Still, always awe-inspiring. It's the rumble, too, that you need to experience. 

From your home or nearby?  

I keep trying to have a cuise roughly when there's a launch- but that's so on and off that it's almost impossible.  

We brought our whole family down to Florida to see a launch in the spring.

 

Instead they delayed it and we all got the flu. Also I got the van stuck in the sand on a side road.

If not for the cost, it would be tempting to schedule some time on the space coast during a launch window, and then take a cruise.

aircooled
aircooled MegaDork
6/2/20 11:49 a.m.

I found the thing I saw about why SpaceX is so efficient (link skips to 28 min in):

https://youtu.be/KA69Oh3_obY?t=1651

 

 

This part where he asks Elon questions really shows the different philosophies.  It's a great video in general, but it is almost an hour long.

David S. Wallens
David S. Wallens Editorial Director
6/2/20 12:23 p.m.

In reply to alfadriver (Forum Supporter) :

I have only seen one launch from home, but that's due to our thick tree canopy. I have watched several from the park down the street. Usually we go to the beach for a really clear view. 

For this one, we ventured south to Bethune Beach. Was the view that much better than the view from our beach–15 minutes away vs. nearly an hour? Maybe, maybe not. But as my wife said, we got to enjoy a day outside.

For the recent in-flight demolition launch, I went all the way down to Titusville. There's a park located across the water that offers a perfect view. That was way cool. I also imagine that it was totally packed for the latest launch. 

Antihero (Forum Supporter)
Antihero (Forum Supporter) UltraDork
6/2/20 12:30 p.m.

I'm glad to see we are doing more with space. I know some think we should spend the money elsewhere but I think exploration is vital to our civilization for growth

codrus (Forum Supporter)
codrus (Forum Supporter) UberDork
6/2/20 12:40 p.m.
dculberson (Forum Supporter) said:

In reply to Keith Tanner :

I noticed that, the interior of the Dragon was light years beyond older ship designs. Everything looked purposeful, clean, and modern.

I suspect that's because most previous spacecraft were designed by long-time aerospace/defense contractors, they primarily build for military contracts and "functional" is the name of the game, aesthetic considerations are far, far down the list.  While SpaceX isn't exactly a consumer-oriented company (hah), there seems to be a bunch of crossover with Tesla who most definitely are.

alfadriver (Forum Supporter)
alfadriver (Forum Supporter) MegaDork
6/2/20 12:47 p.m.

In reply to David S. Wallens :

This launch was a little different, wasn't it?  The orbit of the ISS had the launch going NE out of Canaveral- do you think it helped that the general direction was north toward you? 

One of those things I really want to see- been a space fan since being a kid.  Heck, I even remember some of the words to a kids song to the moon, and pretending that the banana tip in my cereal was a space capsule.  Funny that I still remember that.  I also remember being really bored looking at the small triangle of gray for one of the later moon landings.  

Good thing that we did a trip to the museum the recent cruise to Canaveral.

tuna55
tuna55 MegaDork
6/2/20 12:54 p.m.

Just watched a neat video about SpaceX switching to a space-age material called stainless steel. I snickered a bit. SS is great stuff. I am cheering for them, and hope it keeps the space program going. I am really excited to see Mars. I guess the plan is to have the rover bring back Mars rocks? That sounds amazing. I was completely amazed (pardon the repeat word, but it's the right word) at the Kennedy Space Center being able to touch the moon rock. Mars rocks would be even cooler.

tuna55
tuna55 MegaDork
6/2/20 12:55 p.m.

By the way, continuing my annoyance with the news: We were watching one of the live feeds, and it was interrupted by the news, giving us news about the launch, with a smaller video of the same live feed we were already watching, but with some talking head guy instead, and it was way worse.

codrus (Forum Supporter)
codrus (Forum Supporter) UberDork
6/2/20 1:02 p.m.
Keith Tanner said:

I am not expressing myself well, obviously.  Is lighter better? Hell yes. Is saving "half a passenger" in computer weight a game changer? No, not even close. That 105 lbs (computer plus screens) represents 0.3% of the weight of the LEM (hardware plus propellant).

 While it may be only 0.3% of the total mass, it matters a lot because it's being hauled around everywhere.  Doing some back-of-the-envelope calculations using wikipedia numbers, taking it out would have added 1% to the total delta-v of the descent stage and 1.5% to the ascent stage.  Tsiolkovsky's rocket equation is a bitch.

But it's not "half a passenger" because you can't just add a third person without also adding a bunch of other stuff.  That extra person would have needed extra air, extra CO2 scrubbers (remember that scene in Apollo 13?), extra food, a space suit, extra structure so there's enough room for him to move around and put that suit on, etc.

alfadriver (Forum Supporter)
alfadriver (Forum Supporter) MegaDork
6/2/20 3:01 p.m.
tuna55 said:

By the way, continuing my annoyance with the news: We were watching one of the live feeds, and it was interrupted by the news, giving us news about the launch, with a smaller video of the same live feed we were already watching, but with some talking head guy instead, and it was way worse.

While watching TV, I was also live feeding either the SpaceX or NASA Youtube feed.  When things are happening, they only show what is happening, and make sure that you can hear the talk- which is really cool.  I kind of perfer the SpaceX feed, because they also include the reaction of the employees in the background- which is really cool.

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