Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission • Hacker News Board

Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#231

Post by lodi » Fri, Feb 15, 2019, 4:43 PM UTC

tzs wrote: post #125

luizfzs wrote: post #82

Earlier quoted context omitted.

I saw a video once saying that SpaceX uses general purpose computers on the rockets instead of specific purpose hardware. If I'm not mistaken, they amount to 6 and have a checking system to assure the output of them is the same.

Those "have N copies and compare them" systems then have the issue that whatever does the comparison is a single point of failure. You could use multiple comparison units and have a second level comparison check them, but then that is your single point of failure, and so on. I've been told, but never actually looked it up, that there is a theorem that proves you always have to have at least one single point of failur…

I thought the way these things worked is that each of the N computers can see the state of the other N-1 computers; if your local state differs from the majority opinion you overwrite it, thereby joining the majority.

Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#232

Post by JCharante » Fri, Feb 15, 2019, 6:48 PM UTC

droithomme wrote: post #131

Ianworld wrote: post #105

Earlier quoted context omitted.

I remember talking to a high up on the program at a FIRST robotics event who complained about them running so long. They weren't making any major new discoveries and sucking up resources and mindshare stopping him for kicking off and focusing on new projects. He said nobody would take the PR hit to decide to just end a mission like this so he was stuck.

> I remember talking to a high up on the program at a FIRST robotics event who complained about them running so long. Not surprising at all. Coached a FIRST team for several years. At this point they sell licensed robotics kits with canned instructions for kids to put together and those kids win because of time limitations. The teams that build from scratch and actually contribute discover or learn anything at all ar…

> The teams that build from scratch and actually contribute discover or learn anything at all are intentionally blocked from winning

This is ridiculous, and I'm saying it is from the perspective of having been a student whose team finished fourth in FRC in a recent year (and won multiple events per year), and having volunteered and assisted multiple teams.

While it is true that a lot of lower resources teams may be better off going with commerical off the shelf (COTS) components, such as the Greyt Elevator and Greyt Intake, teams that perform at a higher level will build everything from scratch. Whether this means utilizing gussets or welding, building your own drive train or using the AndyMark prebuilt chassis.

While it is true that some kids may be better off doing research projects, there is nothing wrong with participating in a team. From my three years as a student, I was exposed to developing solutions to split messages up and verify data integrity when communicating over serial with external microprocessors, utilizing version control, setting up Continuous Integration on our repositories, first deploying apps from Cordova to developing Progressive Web Apps, which forced me to learn to use a VPS on Digital Ocean, running a docker swam on hyper.sh, and storing files on S3 and using RDS.

FIRST is what you make of it, and I'm personally glad that someone holding your opinions towards the program is no longer actively interacting with kids in the program.

Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#233

Post by sametmax » Sat, Feb 16, 2019, 8:53 AM UTC

classicsnoot wrote: post #223

sametmax wrote: post #198

Earlier quoted context omitted.

Jumping on the opportunity to have somebody who knows about those things. I used to have a huge garden, and made a compost by barely dumping anything organic on a big pile. It worksed great: low maintenance, never one problem, plenty of compost produced. I now live in a flat, and have composter using worms. I can't make it practical for the love of me. If I put it inside, I get flies, no matter how much carbonated ma…

Definitely! First off, I am biased in my compost preferences and it is always good to hear different opinions. Second, what works for one fails for another, so no sense in throwing more effort into a process that isn't working. On to your situation. In home composting is always tricky. My wife and I do indoor/outdoor because we have a yard. In your situation, I'd advise against vermicomposting for the same reasons yo…

Great, can you email me at lesametlemax on gmail ?

Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#234

Post by blake1 » Sat, Feb 16, 2019, 1:31 PM UTC

ezconnect wrote: post #226

trothamel wrote: post #172

Earlier quoted context omitted.

Sort of. I think the book "Roving Mars" covers this the best. They were worried about a dust storm like the one that killed Opportunity, so they designed the rover to last 90 days even in the pitch darkness of a dust storm. To make sure they'd succeed even in this worst case, they added two additional petals worth of solar panels (IIRC, about a 50% increase in area) to the MERs. Reading a contemporary description, th…

I think they solve the power problem by bringing a nuclear reactor as the main power source.

Different rover. Spirit and opportunity aren’t RTG powered; curiosity is.

Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#235

Post by NL807 » Mon, Feb 18, 2019, 12:47 PM UTC

goatherders wrote: post #181

NL807 wrote: post #134

Earlier quoted context omitted.

It's pretty much what you do in any successful enterprise. Under promise, over deliver.

That's just startup and sales speak. I've found that delivering exactly as promised is more than enough to keep customers happy.

> That's just startup and sales speak.

Nah, it's a method for giving you a lot of wiggle room if you (or your business) fucks up in something.