I just realized something. Supposing we ever colonize Mars (lol!), helicopters and planes won't work there. That means long-distant transport will be either by ground or by reusable ballistic rocket. I'm sure that's not a surprise to anyone but me, but I think it would be an interesting contribution to e.g. setting an old western on Mars.
High-speed rail on Mars will have all the advantages of hyperloop (greatly reduced drag from 1% atmosphere) with none of the downsides (the cost of building miles of enclosed tubing and keeping it evacuated). At Marian sea level you could travel by rail much faster than an airplane at 30k feet on Earth.
Only downside relative to air travel on Earth would be building out the track.
Well thanks for nerd sniping me! This got me googling, and the closest thing to a martian sea level turns out to be super interesting. And so I’ll share the interesting stuff I just learned.
Since mars doesn’t have a sea, there’s no easy sea level equivalent, so (if I understand correctly) they have a level called the aeroid [0] (the corresponding term for earth’s sea level is geoid. ‘aer’ for Ares, I suppose).
At first, this was defined in terms of the level with a specific constant atmospheric pressure, but in 2001, ‘they’ made a new convention based on constant gravitational+rotational potential, since they finally had that data.
So now mars ‘sea level’ is that “equipotential [constant potential] surface… whose average value at the equator is equal to the mean radius of the planet.” [1]
Well, just as on Earth, there are cases where pavement for wheeled vehicles makes sense and cases where trains on tracks makes sense. But I expect rail will be more widely deployed on Mars since typical travel speeds will be higher on account of the thinner atmosphere. Going 300 mph by rail would be a snap, but you'd need awfully smooth and wide pavement, and a steady hand, to drive that fast on Mars. And going significantly faster will require levitation, where there isn't any advantage to not using a track.
They could, provided they have very large wings. Lower gravity helps, but near vacuum on the surface, winds and dust storms are problematic.
OTOH, SSTO is easier on Mars and there will be quite a surplus of rocket engines, at least at the start of the colonization effort. Suborbitals are much easier.
Finally, I think settlements will tend to be closer to each other because it's easier to manage emergencies when one does not require air travel.
Mars is, by Earth's standard, tectonically inactive. You should not expect dangerous marsquakes.
Mars is hydrologically impoverished: you should not expect flooding.
Meteorite impacts might be more severe because of the reduced atmosphere, so more small impacts should be expected. Medium and large impacts should be about the same: rare.
The biggest problems on Mars are air, water, and temperature. All of these have scalar efficiencies, so I suspect an optimal arrangement for Mars would be three cities not very far from each other, so as to be able to provide mutual support while avoiding single points of failure.
Lava tubes can provide adequate protection against radiation and small impacts. Inflatables can provide additional mechanical support for the tube walls and offer space for huge areas (which are not that great an idea, for redundancy reasons).
Not necessarily true - I can see some combo of a Zeppelin and a helicopter or prop powered plane like thing being workable. It may not be as fast as planes we have today but it would likely also have a huge efficiency advantage.
It's really a good sign that these things keep outliving their specified life span, though I also would assume that NASA's life span quotes are probably conservative to avoid the political fallout of "failure."
It's sort of like how companies often make conservative projections because if you make a crazy high projection and almost reach it that's a "failure" to shareholders even if you did exceptionally well.
> It's really a good sign that these things keep outliving their specified life
> span, though I also would assume that NASA's life span quotes are
> probably conservative to avoid the political fallout of "failure."
Cart before the horse.
NASA designates a science goal, which often includes a detailed plan of what to explore. The administration designates a cost budget, a time budget, and a mass budget. These specs then get sent to engineers (at e.g. JPL) who do the best they can to achieve the science goal within the cost, time, and mass constraints. Sometimes they can build a craft that will outlive its initial 90-day science mission by 14 years. Often that is because they got lucky with conditions, i.e. wind cleaning dust off solar panels.
In no case have they built a craft with no specific goal, then declared it's operational life expectancy, and then went and found a mission to do with it.
> In no case have they built a craft with no specific goal, then declared it's operational life expectancy, and then went and found a mission to do with it.
I don't think the message you responded to said that they built the craft then declared the operational life expectancy.
NASA could have designated a science goal which needed 22 flights, and had the same cost, time and mass budget associated with it. Clearly that goal would have been achievable with some probability given that it was achieved. They didn't. The comment in question is speculating about the reasons why NASA might have chosen 5 flight as the target instead of 22 or 222.
It's not the case that they could guarantee 22 flights for the same cost, time, and mass budget. We only know that this design worked after the fact, they didn't have that information in advance. Also, this design may only have achieved 22 flights by pure luck; maybe radiation hasn't struck a key microchip yet, or maybe the dust hasn't degraded the rotor motors as much as expected because there hasn't been as much dust as expected.
> In no case have they built a craft with no specific goal, then declared it's operational life expectancy, and then went and found a mission to do with it.
Regarding that last, there have been at least two cases where a secondary mission was added later, after launch. Pioneer 11 was launched for Jupiter, then retargeted during flight to slingshot to Saturn too. And New Horizons was launched for Pluto, then retargeted during flight to encounter a particular Kuiper Belt object (which hadn't even been discovered at launch.)
Yes, far more than two cases. I specifically reference Opportunity. And sometimes the hardware continues working fine but there is no budget for secondary missions.
I suspect space probes have a pretty steep bathtub curve. Lots of potential failure points early on, then large stretch of low risk of failure, followed by increasing failure risks as it gets old.
So when NASA set a target minimum lifetime goal, it puts them quite far into the bathtub curve, long after all that initial risk goes away.
If it makes it to it's target lifetime, chances are it will last a lot longer.
Especially because it uses an off the shelf Qualcomm Snapdragon 801 processor. Can this indicate that the expensive radiation hardened CPUs aren't necessary on Mars?
I know they had accounted for the need to reboot the processor in the event of a radiation anomaly. I’m interested to know what real world data they’ve collected in the time the helicopter has been flying.
Probably still a "It Depends" answer? What do you want that CPU to do? Curiosity and Perseverance could last a long time and would a faster CPU enable significantly better science instruments? A rover might be able to travel farther autonomously, which is cool but it's a science mission, not a race course.
Why is this one lasting so long? Presumably we know the radiation conditions on the surface so testing more units in a lab is a better guide than one plucky helicopter.
It can, and that's big news. At the very worst you could get away with simpler CPUs and redundancy instead of massively costly and limited supply rad hardened chips.
It is still probably a good idea to have the main equipment running on radiation hardened hardware, while the more unimportant stuff runs on off the shelf components.
That way at least if something goes wrong with the non-rad-hardened equipment, it could be rebooted or debugged using equipment which is rad-hardened
I'm no scientist but that's my take on the matter.
> I also would assume that NASA's life span quotes are probably conservative to avoid the political fallout of "failure."
My trusty SPARCstation had a 3 year extended warranty when bought, but it's still going since 1996. Not getting as much usage as it got when young, but she's a very reliable worker.
> though I also would assume that NASA's life span quotes are probably conservative to avoid the political fallout of "failure."
Isn't that the case with all space agencies? It is usually the best case scenario playing out in most cases, like this one. Even with the JWST, I can safely predict it will last as long as the Hubble, if not longer.
This is awesome to hear. I'm just confused... when the rover landed there was an interview where NASA explicitly stated that the rover would drive away from the copter after 30 days whether the flights were successful or not. Does anyone know when/why that plan changed?
If only they could reach the Rover and have the helicopter dust off the solar panels... Sort of like AAA in the US.
Also, in a Schwarzenegger voice ..."get to da choppa!"
