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Perseverance Rover lands on Mars [video]

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Re: Perseverance Rover lands on Mars [video]

#291

Post by TulliusCicero »

Daho0n wrote: post #220
TulliusCicero wrote: post #69

Earlier quoted context omitted.

That snipe was really unnecessary. Not to mention weird, considering how successful SpaceX has been at dominating the commercial launch sector.

I'm not commenting on the rest of your post but the "dominating the commercial sector" just so you don't think I'm badmouthing SpaceX. Just wanted to add that if you sell X pounds of cargo to the commercial sector but sell the same capacity to the military for X times 3 then your are not dominating but are subsidized by the state and in a position to undercut the commercial competition. It's not just for PR that Spac…

Was SpaceX uncompetitive in its bids for the government launches or something? My understanding is that they were much cheaper than other bidders, not more expensive.

Re: Perseverance Rover lands on Mars [video]

#292

Post by ggreer »

vietjtnguyen wrote: post #278
ggreer wrote: post #225

Earlier quoted context omitted.

If it was made with off-the-shelf parts then it's a testament to how wasteful NASA has become. Building that helicopter took them 6 years and $80 million.[1] 1. See page 20 of the launch press kit: https://www.jpl.nasa.gov/news/press_kits/mars_2020/download/...

They can't exactly procure a bunch of parts and then call it a day. Lots of the cost is tied to the verification and validation. Then there's the system design, requirements engineering, trade studies, system integration, engineering models, simulation, software, environmental testing, launch costs, ground command and data systems, interfacing with the rover, etc. Paying engineers to do all that is what makes it so e…

The $80M doesn't cover the launch costs. That would be part of the $2.4B for the overall rover project.

For comparison: SpaceX's entire Falcon 1 program cost $90M over 6 years. That was to develop two new rocket engines (Merlin & Kestrel), build out the launch site on Omelek Island, and launch five times.

Re: Perseverance Rover lands on Mars [video]

#293

Post by m4rtink »

Sharlin wrote: post #180
teraflop wrote: post #121

Earlier quoted context omitted.

In fact that's exactly what they're doing: the Mars Reconnaissance Orbiter is serving as a communications relay, as it did for previous landers. It's just that since there have never been more than a handful of spacecraft active on Mars at any given time, there's currently no point in spending huge amounts of money to launch a whole constellation of satellites for continuous coverage.

Not only the MRO, but other orbiting assets as well, particularly NASA's MAVEN and ESA's TGO. Even the venerable 2001 Mars Odyssey is still used as needed, I think.

Even ESAs Mars Express is still around - since 2003!

Re: Perseverance Rover lands on Mars [video]

#294

Post by UnpossibleJim »

bregma wrote: post #238
whatshisface wrote: post #231

Earlier quoted context omitted.

Simultaneity is at least as well defined as clock time. Both clock time and the velocity of your reference frame can have arbitrary constants added to them to yield equally valid coordinate systems. So "it's not really simultaneous" is analogous to "it's not really 6:30 PM."

Well, it's 6:30 PM somewhere . lifts glass

From The Hitchhiker's Guide to the Galaxy: "Time is an illusion. Lunchtime doubly so."

Re: Perseverance Rover lands on Mars [video]

#295

Post by m4rtink »

raylus wrote: post #152
notum wrote: post #58

Any JPL/NASA HN users that could comment? That would be beyond awesome! Great job, mission!

JPL Engineer here, any questions I could convey to the slack I'll be glad to feed back to HN

How much overlap is there now that two similar yet 10 years different rovers are in operation ? Is it possible to share some of the human/software/planning resources or are they basically two separate efforts by this points ?

Also, do the Rover Drivers still live on the Mars time that makes their working hours shift by 45 minutes every day, like in the good old MER days ? ;-)

Re: Perseverance Rover lands on Mars [video]

#296

Post by dieortin »

mulmen wrote: post #269
spaetzleesser wrote: post #236

Earlier quoted context omitted.

They should make km the default unit and not miles....

Ever been on an airplane? Altitude was almost certainly measured in kilofeet. As noted in other comments, NASA (like the rest of the United States [1]) does use the metric system. But it doesn’t matter. Nothing about the metric system makes it uniquely suitable to landing on Mars. Or space travel in general. What matters is a consistent standard. Internally NASA could use Armstrongs. Where 1 is the weight or height o…

It does matter. See the errors caused in the past by using the imperial system. The metric system has a number of advantages.

Re: Perseverance Rover lands on Mars [video]

#297

Post by michaelwilson »

tectonic wrote: post #14

You can also watch an EDL visualization in your browser: https://eyes.nasa.gov/apps/mars2020/#/home And read about how it will use Terrain Relative Navigation to find a safe landing spot: https://www.jpl.nasa.gov/news/a-neil-armstrong-for-mars-land... Perseverance is phenomenally complex, its Sample Caching System alone contains 3,000+ parts and two robotic arms. So exited for all the sciencing this nuclear-powered,…

It turns out that they took 640lbs (!) of weight to mars to be tossed off at various points during EDL. The video is worth watching if you'd like some more of the nitty-gritty behind the process: https://www.youtube.com/watch?v=W0NakShgbHY

Re: Perseverance Rover lands on Mars [video]

#298

Post by vietjtnguyen »

ggreer wrote: post #292
vietjtnguyen wrote: post #278

Earlier quoted context omitted.

They can't exactly procure a bunch of parts and then call it a day. Lots of the cost is tied to the verification and validation. Then there's the system design, requirements engineering, trade studies, system integration, engineering models, simulation, software, environmental testing, launch costs, ground command and data systems, interfacing with the rover, etc. Paying engineers to do all that is what makes it so e…

The $80M doesn't cover the launch costs. That would be part of the $2.4B for the overall rover project. For comparison: SpaceX's entire Falcon 1 program cost $90M over 6 years. That was to develop two new rocket engines (Merlin & Kestrel), build out the launch site on Omelek Island, and launch five times.

Sure. I meant it more in the sense that there are some launch costs associated with the Mars Helicopter because it consumes mass budget.

As to the SpaceX point. Yes, I think SpaceX is more efficient with their money than NASA, but this will boil down to a discussion of counterfactuals and degrees of "wastefulness". Was NASA wasteful? What does it mean to be wasteful? What's the threshold? What would it cost SpaceX to build the Mars Helicopter? Can we really compare a launch vehicle versus a tech demo of a rotorcraft operating on another planet? Would that $80M be better spent just funding SpaceX? I don't know. I just don't think it's fair to simply say "If it was made with off-the-shelf parts then it's a testament to how wasteful NASA has become". The engineering has to happen. Could NASA have been more efficient with it? Probably. Was it wasteful? I don't think so.

Re: Perseverance Rover lands on Mars [video]

#299

Post by m4rtink »

vietjtnguyen wrote: post #278
ggreer wrote: post #225

Earlier quoted context omitted.

If it was made with off-the-shelf parts then it's a testament to how wasteful NASA has become. Building that helicopter took them 6 years and $80 million.[1] 1. See page 20 of the launch press kit: https://www.jpl.nasa.gov/news/press_kits/mars_2020/download/...

They can't exactly procure a bunch of parts and then call it a day. Lots of the cost is tied to the verification and validation. Then there's the system design, requirements engineering, trade studies, system integration, engineering models, simulation, software, environmental testing, launch costs, ground command and data systems, interfacing with the rover, etc. Paying engineers to do all that is what makes it so e…

Yeah, with launch windows every two and hal years only, 9 months of travel time, still expensive launch costs and complicated landing requirements you really need to make sure stuff works.

Sure, for stuff you can reasonably test in Earth gravity and atmosphere you can just weld stuff together in a field and then fly it until it stops crashing. Thats a case when you can iterate quickly and relatively easily with lots of COTS stuff.

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