If everything they build lasts longer than expected, not only are they giving bad estimates (which perverts allocation of resources), they are way too smart and experienced to be doing it unintentionally.
Now if Ford Motor underpromised on your car, telling you it would last 2 years, you wouldn't buy it in the first place - you'd never find out that it really lasts 10 years. But I suspect NASA gets away with it because everyone is blown away by even the underpromised result - helicopters on Mars, holy sh-! - and also nobody has experience with how long Martian helicopters typically fly.
OTOH there is approximately 0% chance a Ford is going to last 10 years without any maintenance or repairs.
Take a much more common example: expiration dates. A product going bad before its expiration date is an issue. Potential a massive one that could kill people. A product that remains in good condition after its expiration date is fine. As a result, expiration dates almost always occur far before the product actually expires.
That is salesperson talk. NASA has been doing public communication half a century too, and they know what people will take from it.
Your assessment of the estimates is basically MBA talk.
They designed the helicopter for 5 flights. It is very likely the case that the requirements that a rotary wing aircraft can operate for 5 flights with minimal operator intervention, and only between missions, resulted in an helicopter that had a longer lifespan. Could they have done it cheaper? Maybe, probably, but most likely with a much higher risk of failure, and given the time, distance, and cost, and the organization doing the work, I am pretty confident that the team made the right choice.
Think about it like having to get across town after work for some reason. If it’s your buddy’s party and it’ll run all night, you might take the bus or call an Uber but it’s no big deal if you’re a few minutes late. If it’s your party, you might pay to park your car nearby or have a ride waiting for you. If it’s the meeting where you’re selling your company or announcing your presidential campaign, you might have a helicopter waiting on the roof. NASA’s stuff is all like that last case because the base costs are so high - shipping anything to another planet and waiting years to do it again, if you are given the chance, costs so much more that it makes sense to pay extra to build everything with deep safety margins just so you can say the odds of failure are comfortably low.
They knew internally that it could fly 16x more. They just didn’t want to say it in a statement publicly.
NASA and aerospace as a field traditionally have a bias towards that kind of overlapping safety margins because the kinds of failures they get destroy the entire air/space-craft. If some MBA at GE cost-optimizes your dishwasher, they’re better off trimming “waste” until it dies the day after the warranty expires as long as it doesn’t fail in a way which causes you never to buy their brand again. NASA faces far more catastrophic failures and because their systems are all custom with economy of scale for large product runs and their missions by necessity have a hefty base cost so it doesn’t make sense to save $50k on rover parts when you are paying $500M to ship it to Mars.
These are novel and truly unprecedented space missions. There may yet be a future in which we can confidently predict outcomes at scale, but we are not there yet. Being conservative in assumptions is a virtue, and hopefully is emulated in every future mission.
(And if your target is at least 20 but you say it's 5, you can miss your target and still claim you succeeded.)
Look at the reporting from NASA. For instance[1]:
> “Less than a year ago we didn’t even know if powered, controlled flight of an aircraft at Mars was possible,” said Thomas Zurbuchen, the associate administrator of NASA’s Science Mission Directorate. “Now, we are looking forward to Ingenuity’s involvement in Perseverance’s second science campaign. Such a transformation of mindset in such a short period is simply amazing, and one of the most historic in the annals of air and space exploration.” ** > “This upcoming flight will be my 22nd entry in our logbook,” said Ingenuity chief pilot Håvard Grip of JPL. “I remember thinking when this all started, we’d be lucky to have three entries and immensely fortunate to get five. Now, at the rate we’re going, I’m going to need a second book.”
"One of the most historic in the annals of air and space exploration"? Or here[2]:
> NASA's Ingenuity Mars Helicopter completed 71 flights since first taking to the skies above the Red Planet on April 19, 2021, far exceeding its originally planned technology demonstration of up to five flights.
Of course, this makes it to the Wiki article[3]:
> The helicopter's performance and resilience in the harsh Martian environment have greatly exceeded expectations. The aircraft surpassed its required altitude and flight duration specifications soon after beginning operations on Mars. This allowed Ingenuity to perform far more flights than were initially expected of the aircraft.
Or look at how XKCD has a comic about "Wow, I can't believe this rover exceeded our expectations by so much!" for both Spirit[4] and Opportunity[5].
At this point, it's hard to not see this framing as NASA spin, one that people keep falling for over and over again.
[1] https://mars.nasa.gov/news/9146/nasa-extends-ingenuity-helic... [2] https://mars.nasa.gov/technology/helicopter/#Helicopter-High... [3] https://en.wikipedia.org/wiki/Ingenuity_(helicopter) [4] https://xkcd.com/695/ [5] https://xkcd.com/1504/
One is a playfully satirical exaggeration of capabilities. To the extent it offers a commentary, is fully crediting a rover for it's toughness and longevity.
The other approaches the longevity from a perspective of sentimental affection for an innocent rover who grows increasingly lonely as it's mission grows longer and longer. It does not imply prior knowledge or PR spin on the past of NASA.
Neither of these really work if NASA says, "We're hoping for a decade, but our minimum goals are 90 days." It works because of the NASA spin, "Wow, this was only supposed to be a 90 day mission/5 flights, but we can't believe how much these things have exceeded our expectations!"
If people are continuously telling you their work is so amazing that they're blown away by how much the results have exceeded their expectations, you should probably question how honest they're being with you.
Or "NASA says there's going to be a major announcement tomorrow about a discovery on Mars!", and the discoveries are usually "we've found yet more evidence that Mars used to be wet."
Even the missions themselves - there's been a lot of talk about how Perseverance is collecting samples as the first part of a mission to send them back to earth. But the difficulty is in launching a return flight from Mars, something we're nowhere close to being able to do at the moment. You have to wonder how much of the sample caching is really useful, and how much is just a way to look as if were making progress on something that's still incredibly far away.
Cyberdyne industries: I never said you would die at the end! Aieee my eyes!
If it broke in those two years you’d be very upset, but if it does last longer that’s a bonus.
Unlike with software, where they call that "support" and try to scare you into their next version immediately after that ends.
Unfortunately, the automakers are slowly picking up those practices from software.
We’re talking about on-off speciality devices designed to perform a task where there is no possibility of repair or service. They’re overbuilt to provide the best chance that the main mission is accomplished. Once that’s done they can keep going until it breaks.
Is that actually the case when it comes to the helicopter in question?
So, we keep having gear designed that shows us exactly what could happen for longevity while accomplishing the actual mission goals for the same budget
NASA built in lots of margin to help ensure they met their objective, especially considering that it's really fucking hard to get a new helicopter to mars if it breaks.
Furthermore, you are answering it with a “they must have known!”
I just don’t see how you can know this. (For context, I work at JPL and interact regularly with some of the Perseverance team, but nobody from the helicopter team, which was very small.)
Some context. The helicopter was originally quite controversial because it had no clear science rationale (mission science requirements did not imply a need for a helicopter). My understanding is that it was put on as a tech demo and (paraphrasing) cool thing. The lab director at the time was a proponent.
Of course it was a huge success.
Because of its precarious status, it was not designed to fly a lot. Planning flights takes a lot of resources, coordination with the rover takes resources, etc. Bandwidth, time, and people. My point is that the “plan” was kept small partly because these ancillary costs had to be kept down. This would hold even if the hardware could last forever. The tech demo must not get in the way of the prime science mission, which had already been planned.
The use of COTS components is another factor. The effects of radiation on microprocessors (in the Mars-surface or deep space environment) are not really well known, as a practical matter. There is just not much engineering experience with how bad it can get. So the longevity of the Snapdragon was (AFAIK) highly uncertain, not to mention whatever other COTS components were on it.
Hope this context is helpful.
I know nothing about the helicopter in particular but as I pointed out, NASA seems to very frequently underestimates longevity and performance (not a crime at all and maybe politically wise); I can't remember when they've overestimated. Forget my impressions in prior posts - how and why does that actually happen?
> tech demo ... precarious ... not much engineering experience
Also, while I've taken the opportunity of spare resources to do experiments (though not usually on Mars), I'm careful about timing and appearances - I don't want to embarass my team or partners with a failure that's visible to outsiders who wouldn't understand it was an experiment, and would think we just failed at our jobs.
Everything NASA does seems to be on a very public stage, interpreted by endless outsiders (like on HN :) ). The whole world watched the helicopter's first flight. How can someone approve the helicopter, and promotion of its flight, and risk the world saying, for the next decade, 'that crazy helicopter embarassment shows we need to rein in NASA', blah blah blah? NASA's reputation is very important to humanity.
Thanks for sharing what you know. You guys do amazing things; people are so jaded that they don't realize how incredible it is.
Heli was on board the lander but it was not subject to the same risk constraints.
I think your probabilistic risk assessment has something going for it, but not all risk would scale that way.
I’m surprised at the self assurance of some of these comments!
Directed (in essence) means that the National Academies (NAS) decadal survey recommended that specific mission. (They specify the what but not too much about the how.) A directed mission is assigned to an implementing center (JPL , GSFC, etc.) And they build it to accomplish their best interpretation of the NAS DS guidance.
Sometimes this can be expensive, more expensive than the NAS expected (JWST). And sometimes the imperative to make it work to accomplish the “down from the NAS” guidance, with near 100% certainty, in a novel environment will result in over performance like you noted.
The noteworthy directed missions are mostly large flagship missions.
The other category is cost capped competed missions. (VERITAS is a recent one, so was New Horizons, but they exist in astrophysics and earth science as well as planetary; see for example https://en.m.wikipedia.org/wiki/New_Frontiers_program). “Tell us what you can build to accomplish some portion of the following high level science goals in $300M or less”
Over engineering is not really possible under those conditions! You will be competing against the absolute best concepts and teams in existence. So the budget is really squeezed.
These two mission types are complementary in the obvious way. The flagships push engineering capacity way forward, and the competed missions have a lot of innovative concepts within a cost cap.
There are also pure tech demonstrations (often piggybacking like the helicopter did) and certain other categories but the competed/directed split is primary.
when they get the funding for the mission is when they make the lowball estimates, but with the funding they build equipment that is much more durable. It's hard to see where any perversion takes place
(*I don't necessarily mean the practice of shooting a rocket into space and launching a telescope, but the ability to build an object that can perform that exactly to its specifications under those kinds of circumstances.)
Nasa, congrats on successful mission, which now ended.
I see what you did there.
IMO, Webb is a bad example. It was super over budget, late, and experienced a litany of problems.
In contrast, most un-manned NASA projects are roughly on budget and generally have few issues. And even the ones that do, NASA often figures out how to correct them like the Hubble telescope.
This is simply not true. Maybe for some of the smallest Discovery or New Frontiers missions, but then those aren’t actually built by NASA/JPL.
Mars Sample Return is also famously insanely late and over budget, and so have been most flagship missions.
JWST was built by primarily Northrop Grumman engineers
Give other space agencies the budget of NASA, let experience marinate and you will see similar performance. NASA does not have some sort of magical intrinsic property that makes engineers perform better by sheer effect of working under its umbrella.
For example, what requirements for the Ingenuity helicopter were set for the engineers? Five flights or a 100 of flights?
Under promise, overdeliver, is a nice way to say that you're dishonest with the client. The fact you can overdeliver means you're making some trade-offs elsewhere, e.g. in design/production price, time, weight or somewhere else.
Overdelivering is a nice byproduct, but it shouldn't be the goal.
It has nothing to do with dishonesty. Though I have no doubt that it might be used that way, that's fraudulent and a whole different ball-game commercially.
In such a situation, why not say like it is? Just explain the client the situation, what's the risk and for what additional cost it can be lowered. And I have no doubt this is what was happening in NASA, in other words this was no "underpromise and overdeliver", this was "explain the situation and agree on trade-offs leading to the best ratio of positive outcome for the price".
I think the only situation where this approach is valid is when your client is not sophisticated enough to understand the trade-offs and make an optimal decision.
But officially the statements are always set as an "underpromise and overdeliver" thing because the clients are not sophisticated enough to understand the trade-offs.
By clients I mean politicians and the general public, who take even delays or testing-to-failure as being actual failure.
That doesn't work well when communicating indirectly, through politicians and journalists, to the public at large. It may not work when communicating to elected politicians.
That brought to mind the glass-half-full / half-empty (false) dichotomy: The engineer thinks the glass is twice as big as it needs to be (or maybe 30-40% bigger to allow for a safety margin).
Unfortunately this leads to uninformed reporters to make stupid claims like "a probe only designed to last 90 days...". There's no self destruct or planned obsolescence in NASA probes. They don't have an egg timer set to 90 days and then explode.
The probes are designed to last at least as long as the ability for their consumables/power supply lasts. Consider the stresses of launch, transit through space, and insertion/landing are way worse than day to day conditions for a lot of probes. If they can survive all of that rolling around a desert is relatively easy (in comparison). If Ingenuity made one successful flight there was little reason it couldn't make more so long as it had the appropriate power available and the Martian Space Defense didn't shoot it down.
Ingenuity didn't overperform, it performed according to its actual design and construction. It only overperformed misinformed media expectations.
C'mon let's not blame the reporters. NASA pushes this line - why do think everyone repeats it, using the same language almost every time? You can even see it here on HN.
NASA never wants to say a probe will probably last longer than its primary mission because then reporters go the complete opposite direction and claim NASA said a "probe failed to last the claimed X+Y flights".
NASA’s got a history of their rovers overperforming like this. Between this and Webb, it’s hard to argue they’re not the best out there.
It's underpromising and overdelivering. It's a smart strategy because it's just hard to get stuff to work in space and on another planet. So it's best to underpromise.
You can bet that the internal goal is a lot higher than the public goal.
That's the wrong kind of overperforming.
Sure, there is less lift... But there is also less drag. So your rotors can go far faster with the same power input - and, roughly, it looks like the power needed to hover (for a craft of a given mass and size) is actually less on mars due to the lower gravity, despite the rotors moving super fast.
I think this is a misconception. Even in water, you cannot provide lift equal to your bodyweight.
It is easier to swim (vs sink) in water because the water gives a large amount of buoyancy.
However, in air and on mars, buoyancy is small enough to be negligible.
FYI, these two things are __directly__ related.
Lift = c0 r v^2 A
Drag = c1 r v^2 A
=> Lift = c0/c1 Drag
You should be able to reason this out too. Think about how you generate lift. The blades spinning have to push something, right? What is it pushing? Then think about drag. What is that dragging against? Is it related to the thing you're also pushing against? I think you know the answer.
Yep. Setting maths and motors aside... it's why helicopters have service ceilings and why no one has built a helicopter that can fly away into the stratosphere.
Just like the mars helicopter cannot fly on earth.
Great ROI, we should keep going on bigger projects. All that data...phew.
Working there must feel like pure Americana each time you tap a key. I'd be coding extra just to enjoy that, especially seeing the level of impact these teams have. I wonder if they drink coffee while they build or if they found that it reduces performance for the engineers or for the astronauts?