NASA says Webb’s excess fuel likely to extend its lifetime expectations
blogs.nasa.gov
blogs.nasa.gov
Lots of talk about refueling even with the 20 year lifespan, from what I've gathered having watched a lot of the NASA conferences and livestreams this past year, with this amount of operational fuel capacity the problem in 20 years will be on operational lifetime of wear components, not just the fuel.
The reaction wheels are _large_ moving parts on the JWST. The cryocooler for the MIRI is a very finely calibrated moving part. It's a closed system, but still relies on pumps and electronics. After 2 decades of operation it's very likely that these will be experiencing some issues.
While in 2 decades it might be feasible to refuel the JWST, it seems very unlikely it'd be worth it given the operational wear of every other component. Had we used too much fuel to correct the course to get where we are the math may have been very different. Seems to me that we're fortunate that we can instead dedicate resources to the next-gen observatories!
Attempts to refuel will be completely unneeded.
Edit:
This seems to be a controversial opinion (based on down votes). To clarify, my expectation is that if launch costs have come down as much as people suggest, launching a new and improved (potentially significantly larger) space telescope would be a better use of funds than a complicated and risky refuelling mission. There will be many lessons learnt from JWST that by then there will be an appetite for something new.
My hope also is that if the cost to launch has come down so would the development costs of any new satellites, leading to reduced costs for science missions.
I grew up at Lick Observatory in the Bay Area, and really love ground-based stuff, but I'm somewhat familiar with their operations and I guarantee it's got nothing on space 'scopes.
You literally could have 1000 tons of liquid nitrogen delivered to your telescope if you needed to, if it saved $1 billion.
I think people still aren’t understanding the ambitions of Starship. We’re not talking about a 30% improvement in cost. But a 300000% improvement in part because you could even afford human technicians…
... not at the same wavelengths. The earth's atmosphere is largely opaque to IR, for instance.
There are some things you can only do beyond the atmosphere.
Not that space isn't also hard, but each environment has both affordances and limitations.
Propellant is often a key limitation to life of a satellite, especially for earth-observations sats in low earth orbit (the opposite of the JWT), and it's well worth refuelling a satellite in principle.
The JWT is a _lot_ of expensive hardware. It's not crazy at all to think about refuelling, especially if it's expending significant propellant to say in a stable orbit +/- maneuver for imaging operations.
All that having been said, refuelling is still a long way from reality, and despite a lot of companies marketing refuelling ports and similar things, it will be a long while time until it's a realistic solution. Over the lifetime of the JWT, it probably will become feasible, though.
It's fair to say that over two decades, additional capabilities will exist.
Given the advances in launch systems, both in situ assembly (large structures w/o complex packaging and deployments), and planned servicing and replaceability could mean that both arguments are true:
- We'll have bigger, more capable, and/or simply more observatories.
- Those themselves will be capable of being serviced and upgraded over their own lifetimes.
Keep in mind that one element of science that's advanced by such projects is engineering systems for space environments themselves. Vacuum, radiation, micrometeorites, station-keeping, gravitational flux and variance, materials handling (cold-welding, lubrcation, moving parts, etc.), thermal management, and design-for-servicing itself, all factor in to considerations.
It seems highly probable to me that any such servicing itself will all but certainly be robotic. At L2, speed-of-light issues are a factor as there is a one-way signal time of five seconds, long enough that direct control of physical manipulators is no longer feasible, or very slow. (Imagine that you reach for a wrench, and ten seconds later, see that your hand has actually extended and contacted it.) And putting humans in such a location, only reachable over many days or weeks, well out of Earth's magnetosphere radiation projection, would be fantastically expensive.
The LUVOIR is the next generation - https://asd.gsfc.nasa.gov/luvoir/ and https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infr...
The design for it is really impressive.
> LUVOIR Architecture A (LUVOIR-A) features a 15-m diameter primary telescope aperture and four serviceable instruments
JWST has a 6.5 meter mirror.
The larger the aperture, the smaller the resolved object that we can look at. For example, looking at the central black hole of M87 which is on the order of "diameter of the solar system" ( https://xkcd.com/2135/ ).
However, the only reason we are able to resolve it is that it is so bright.
But if you want to look at dim objects, then the area of the light gathering is the important value. That is why Arecibo was so important ( https://ui.adsabs.harvard.edu/abs/2005AAS...207.2907D/abstra... )
For the HSA - it used the largest of the radio dishes available - https://science.nrao.edu/facilities/vlba/HSA
The Green Bank Telescope 100m and the Effelsberg 100m telescopes are much more sensitive than the VLA... but the VLA can resolve 0.2 and 0.04 overall.
So yes, we could send up a bunch of 3m space telescopes out to the L2 point - but how many individual miniature instruments are we going to need to make for each, how much propellant will be needed for each, how will you keep the cold side cold (size matters)?
While I'm not a rocket scientist, I'm not sure that those are easy problems to solve... and I feel like they're much harder problems to solve than ones that the JWST and the current line of telescope proposals have.
>It's fair to say that over two decades, additional capabilities will exist.
Capability doesn't create need, in either a technical or economic/resources sense.
Too many people are interpreting "unneeded" as: "a satisfactory amount of fuel for a long-enough lifespan, but more would be better"...
When it really means: "fuel is no longer the most likely controlling/ limiting factor as to what ultimately triggers the end of webb's usable/useful lifespan".
Even if fuel ends up being the actual limiting factor, no ability to extend the (likely) lifespan of ALL the other critical components makes refueling a high-risk, high-cost, low-return venture.
And that fuel itself, over 20 years, could prove not to be the limiting factor.
There remains the point that you've stated, and are again asserting, an absolute condition, that refueling is completely unneeded. Given that a now + 20 years JWST that is still functional except for fuel might exist, that categorical absolute remains unjustified, regardless of how probable it might be. And again, it's specifically how you're communicating this that seems to be raising objections.
None of us have a perfect view of the future. JWST itself offers only an improved view of the past, after all.
In what hypothetical scenario does fuel deplete at a greater than expected rate, in a way that wouldn't also call into question the reliability and expected lifespan of the remaining limiting factors?
Accidental commanded release? A leak? Station-keeping being more demanding than expected? Those would all move risk-v-reward in the wrong direction.
And it doesn't substantially decrease the cost or risks, other than what might be gained by an extended development period, which would need to be weighed against simultaneous advances better applied to and spent on a successor.
So maybe not an absolutism, but an already highly-unlikely proposition who's chances of implementation just decreased dramatically due to the new information at hand.
[0] By ending up with an older/ closer to failure but refueled satellite, and a decreased relative value of remaining potential science/observations, presuming highest value science is done first.
They are not the elements of your initial nor follow-up comments with which I've had issue. And you continue to not address those.
As for what might lead to low-fuel-but-serviceable observatory: reaction-wheel degreadation shy of failure (there are multiple redundant wheels for each axis of rotation), possibly some kind of solar-storm or solar-wind interaction which increases station-keeping requirements.
It's difficult to foresee what previously anticipated scenarios might emerge, for all the obvious reasons. But if I had a $10 billion low-on-fuel observatory on my hands, it was still turning in good science, and my capabilities to provide it with fuel had improved markedly, and there was nothing else obviously imminantly limiting lifetime ... I might opt for the top-up. Even at a cost of a few sheckles.
Keep in mind that the opportunity cost isn't the amortised value of the observatory, but its projected future life and the cost of replacing that functionality. I don't know what the associated values here are. I could envision a reality in which those turned favourable for a refueling mission.
Which, again, contradicts your original, and several-times-sustained, "completely unneeded" assertion.
The horse seems quiet well flogged, and in the interests of a peaceful death, I'm begging off further beating of it.
Of course it does! Today we have all kinds of needs that people 20, 100, 1000 years did not have. That's because the capability to do something created the need for it.
For an obvious example, people need iphones. Nobody had one 20 years ago.
For another, deodorant wasn't needed 100 years ago. The need for it was totally created by the ability to manufacture it.
Capability allows the market to exist and creates potential for demand.
For certain levels of actual demand and saturation, social/cultural normalcy and expectations might lead to "need" as you describe it.
But in this case, I meant specifically that Webb, given 20 yrs of remaining fuel, won't suddenly "need" refueling if the experimental technology suddenly becomes avaliable in 19 years, as the remaining system also approaches end of life.
Fuel is no longer the most likely point of failure for determining lifespan. That might have been different if Webb had to use more fuel on its trajectory burn, had only a few years of fuel, and the technology was extant/eminent and cheap.
The risk-v-reward calculus would completely different, but unlikely to change at this point.
If my truck throws a rod on a roadtrip in Alaska and I limp upon a gas station as my 20yo dying truck burns the last of its gasoline... I don't "need" gasoline, I need a flight home and a new truck.
I wouldn't worry about the junks, they're fake internet points that mean nothing.
I believe the GP is correct: wear and tear on existing components means that fuel won't be the only issue in 20 years. Hubble has been serviced 5 times [1] for example.
Part of the complexity (and thus cost) for JWST was all the issues introduced by trying to fit a 6.5m mirror on existing rockets. All those moving parts and points of failure have design costs.
What you may find in 20 years is that we'll want to launch an even larger mirror and/or use interferometry between multiple telescopes to improve effective resolution.
[1]: https://www.space.com/15892-hubble-space-telescope.html#:~:t....)
1. People like to hate on things and people just because they're popular when there's literally no other reason; and
2. A large number of people will let their personal opinion drive their behaviour. Elon is a dick, no question. Because of that some people will just downvote or speak ill of SpaceX or Tesla. Worse, this dislike can be used to rationalize pretty antisocial behaviour (eg doxxing, swatting).
What SpaceX has done is nothing short of astounding whether you like him or not. I'm not sure of the exact number but I believe SpaceX has raised <$20B and brought launch costs from >$50k/kg (Space Shuttle) to $1-2k/kg to LEO. It seems highly likely that Starship will drive that below $1k/kg, possibly by a lot.
By comparison, a single SLS/Artemis launch is likely to cost more than that.
And if you think it's just a question of throwing money at the problem, just look at the abject failure that is Blue Origin (fun fact: Blue Origin was founded 3-4 years before SpaceX).
I would bet big that most people on here have a fairly balanced opinion of him that roughly would look like:
- Almost single handedly accelerated the electrification of cars by a couple of decades
- Together with many amazing engineers, scientists and more, led to huge reductions in launch costs and increased frequency of launches
- He acts carelessly online with respect to the law around securities
- He acts carelessly online when he wants to insult someone
- He doesn't really care much about light pollution that affects astronomers
- Overhypes many of his ideas and doesn't recognise any criticism of his failures
- Has an implausible idea that we can colonise Mars this century
I am both impressed by the man and have a few misgivings. Like any human being he is multifaceted.
But like anyone he does idiotic things at times but I suppose they are amplified by his strange life.
I wouldn't say he's a "pariah because of his wealth." If anything, he's probably a pariah for consistently, wildly over-promising (overshooting "optimist" to land in "liar" territory) and being a jerk (e.g. defaming that the cave diver, among other things).
Then add to that obnoxious fanboys who've made him a weird tech Jesus, and who defend him and bring up his brain farts at every opportunity. I, at least, wouldn't mind never hearing about him again. Lets hear about the cool people who actually did the cool stuff (and just happen to work for companies he's invested in) instead.
Instead of a huge sunshade, use a telescope tube and a huge amount of liquid helium (even the relatively small amount in Spitzer lasted many years, and this is one instance where mass directly translates into time). Instead of big unfolding mirror, use a monolithic one.
This would actually be technically superior to Webb (colder mirror and instruments than you can get with the typical Webb cryocooler, less starlight impacting the instruments as your telescope tube with baffles shields it better, less diffraction off the mirror segment interfaces) and ought to be potentially much simpler and cheaper. And you could afford to build more than one, allowing you to reduce risk aversion slightly and increase telescope time.
Yeah you might be able to get bigger and heavier but it still needs to contend with launch forces.
Now assembling it in space might change things… but I’m sure that has its own challenges. And even then you’d probably want a space elevator instead of rockets to get your people and equipment int local orbit.
The Arian 5 costs around $185M to launch, they therefore need to make sure it works first time.
Starship is estimated to be $2-10M.
Speculation is somewhere in the 70%-90% of original cost.
Doing it after the fact--- some design work would be saved, but how much of the tooling and supply chain still exists? Parts are going to need re-engineering, etc.
Size constraints are particularly obvious. For instance, it's 6.5M diameter mirror needed to fold up for launch to fit inside the less than 5.4M diameter fairing. That would fit comfortably without folding in Starships 9M diameter. The sunshield wouldn't quite fit unfolded (14m x 29m), but you can almost guarantee that it would have had a simpler deployment mechanism.
Mass constraints are maybe more important, but less obvious. JWST weighs 6161 kg, Starship is aiming for a payload of more like 100,0000 kg, and by taking advantage of orbital refuelling the capability to put that anywhere instead of it being severely reduced past LEO. That means you can use heavier mirrors instead of optimizing them for weight, you can build your structures out of easy to work with materials light metal, instead of hard to work with ones like carbon fiber. You can oversize parts, and include redundant ones if you think they might be needed.
Even if you totally ignored the cost of the launch, the capabilities of a super heavy launcher would make a huge difference. The cost is the icing on the top. It means that as long as you can build a second version for substantially cheaper than the first, you don't have to design the first so that it never fails. For instance, you don't have to design your heatshield on earth and never test the design in 0G until it's on your 10 billion dollar satellite that has to work...
Imagine instead launching components that could be docked together in orbit, tested, and then boosted to it's destination orbit.
You can also remove large categories of risk by freely spending mass and volume.
> Starship is estimated to be $2-10M.
Don't believe the hype. If Starship works out, they can beat other paths to orbit by a fair margin, but it's not going to be a >10x reduction. Much likely much less than that, too.
There should never be such an expensive program again because hopefully we'd realize its easier to also build a massive 1-off rocket for it instead of years developing awesome folding things. Has all the money SpaceX have ever spent so far even come to 10 billion yet?
cost of a new JWST without a foldable mirror and a static sunshield: $2B
why not do both?
My point it is, we have so few space telescopes that even having time on an "outdated" one is still pretty valuable.
EDIT: Maybe a better example, it's not much use for a first-world person to use a ten year old smartphone, since current smartphones are much more capable and they're comparatively cheap. Planes, on the other hand, are used for decades, since simply buying a new one is very expensive. This is despite it's tech being far superior.
It's the massive capital expenditure on the telescope and its infrastructure that is the significant limiting factor on the pace of putting newer and better telescopes in place.
Same thing in this case: instead of visiting Webb, they could build a new Webb without all the origami, and assemble it by hand in orbit for a tiny fraction of the cost, and end up with two of them. Then, maybe put different instruments on the second one.
A telescope that can see back to the beginning of the universe is never obsolete to astronomers. The Hubble is 'obsolete', but there are plenty of astronomers that would step over their own mothers to get time on it.
> but there are plenty of astronomers that would step over their own mothers to get time on it.
May I suggest "there are plenty of astronomers who would cut their left hands to get time on it". Similarly florid, but does not propagate the meme "people will often be evil for the right price" -- that meme is self reinforcing, the more we believe in it, the more true it becomes, and the worst the world becomes as a result
I believe the world becomes even worse when people are unable to speak candidly, frankly, and in their own way. Being able to extract and recognize the meaning behind someone's words, in spite of any perceived flaw in word choice or phrasing, is one of the hallmarks of a mature and intelligent individual.
This belief that controlling how people speak will somehow make the world a better place seems somewhat quixotic.
100% agree. The way we talk, I think, matters. The stories we tell ourselves help shape us. But so does it matter how we try to change it.
Forcing/controlling the way people speak is a remedy worse than the malady 97% of the time, and certainly in the present case.
(Also, it is reasonable that you would interpret my suggestion as an attempt to control, given some elements of the current political climate)
Another example of a poorly told story that worries me: https://www.theguardian.com/books/2020/may/09/the-real-lord-...
best case you have two working mid-IR telescopes in space instead of one. i don't hear any astronomers complaining about that scenario!
also the irony here is that the only the only client this company has now is itself to launch his telecom satellite swarm, which in turn will have a negative effect on ground observations, both in VIS and RF bands. astronomers heavily rely on ground based observations, because on the contrary to space telescope the can modify their instruments easily.
you can do a lot with other technologies, for instance diffractive lenses, chronographs as a separate spaceship, etc, etc... the best for a telescope is not always to have the biggest single piece mirror.
i know i know, i'll get heavily downvoted for the above, i just don't like that the said company test their stuff in a middle of a natural reservation.
I read Musk's statements regarding this towards his workforce as a pure power play to put pressure on them working even harder on ongoing issues like you mentioned.
That being said - if you can produce n amount of engines per time frame, I am positive that they manage to achieve n*x amount of engines per the same time frame as well.
Wasn't that a bit of over-inflation from dodgily-backed NIMBYs, especially in a state where petrochemical industries have abused a lot more natural environments?
Also, sure you can have more complex methods to get to the stage where it's analogous to a single large mirror, but that's why it took 25 years to make JWST (amongst policical reasons too, but still).
If constellations are so bad to astronomy, why do ESA want one?
Finally, I think you'll find KSC in Florida is slap bang in the middle of a huge nature reserve, as it has been for the past 50+ years
I don't think they realistically stand a chance to outcompete SpaceX within the next ten years on any dimension, after all, SpaceX is a fast moving target itself. But that's just my opinion, so we'll have to wait to see how it plays out.
It would be great to have a real competitor to SpaceX, that can't come soon enough, I do give them better chances than Bezos and his toy factory.
Please, just watch the interview. It might change your opinion by listening to the plan, I know I felt much more optimistic about more serious players in the field.
I'm not aware of any reusable vehicles by ULA and all the current flights are fully booked, they're sold out of their current block. There were only a handful of launches last year, I think Electron actually flew more. For the new, they're waiting for engines from Blue Origin but they'll probably end up using RS as it doesn't look like BO will deliver.
The Russians (and Chinese) are basically copying anything SpaceX in terms of reusable heavy lift, which might be a good plan in the long-term but it's not that innovative.
I think long term if Ariane Space and ULA don't adapt that they'll die unless they keep being subsidized. But if SpaceX manages to reduce cost even further then that will make no sense, it is already very hard to justify.
I guess you must really hate NASA then.
> Visitors to Kennedy Space Center Visitor Complex are often surprised to discover that they are just as likely to be greeted by an alligator or dolphin. This is because Kennedy Space Center sits in the middle of the Merritt Island National Wildlife Refuge adjacent to Canaveral National Seashore, one of the largest and most diverse wildlife preserves in Florida. In fact, the refuge supports one of the highest numbers of threatened and endangered species anywhere in the nation.
https://www.kennedyspacecenter.com/blog/07/the-wild-side-of-...
Much of it was built before the EPA existed, so routine was routine. But, it is still being expanded, lately on behalf of SpaceX. Scheduling in lots of studies and meetings just amount to delaying, if they can't actually affect whether the paving happens. No amount of public hand-wringing gives a turtle back the nesting site its ancestors have returned to for a million years, or a hundred million.
If they've built on 5% of the land in 50 years, then we should have another 950 years of expansion, at that extrapolation.
You are aware there is a conservation programme running too?
If the supposed conservation programme doesn't actually block paving, then it is what they call a formality. Business-as-usual is routine.
The US space program was practically moribund for those 50 years. The paving was done quickly at the start. With space activity ramping up, paving will too, as we see starting already. What are you demanding as a definition of "routine" beyond paving where they like, when they like?
You say they are routinely abusing the area and all I'm getting from that is that they've paved over areas, 5% of the area. How is this routinely abusing the area?
Could you post an journal article explaining how this has routinely abused the area and put the ecosystem at risk?
There's still cause for optimism, NASA hardware has a reputation for outlasting its designed lifetime by quite a bit.
electronics on the voyager still work, 45 years after launch.
it is possible that things will break. it is also possible that they won't. we'll see in 20 years, but having an option on the table in case they do work is simply prudent engineering.
But I also just wanted to point out as people discuss re-fueling that some of the concepts for this are not just open up the fuel tank and add more fuel but it might be operationally simpler to make a satellite that attaches like a jetpack [0]
I don't think they can know for sure, however the bearings have been designed with this in mind using ceramics. Also I just realised with the JSWT going around the L2 point it won't be cutting through the Earth's magnetic field, mind you it will be exposed to the direct solar wind.
Question for astronomers: Based on the linked article from that blog post about the five LaGrange points relative to the Earth and Sun (https://webb.nasa.gov/content/about/orbit.html) are there similar points associated with the other planets? If so, how does the heavier gravity of the Sun (for a planet like Mercury) or the gas giants and their large moons impact the points?
I don't think I understand your question about the sun. The Lagrange point used for JWST is an Earth-Sun one.
- The ratio of masses between the two bodies is sufficiently large.
- The mass of objects orbiting at or near the Lagrange points is sufficiently small.
There are Lagrange points in the Earth-Sun system (JWST will orbit near L2), the Earth-Moon system (the "L4 Society" is named for one of these, proposed as the location for permanent habitable space colonies), and the other planets of the solar system and the Sun.
For bodies of sufficiently similar masses, the Lagrange points aren't well defined, as with Pluto and its comparatively giant moon / sister-dwarf-planet Charon.
And there are limits to the mass of an object which can be orbited at a Lagrange point. It's not possible, for example for there to be a "twin Earth" orbiting opposite the Sun from Earth, at the L3 point, as the mass of that object would destabilise the entire Earth-Sun-Twin system.
Lower mass of the secondary system would move Lagrange points closer to that body, higher masses would place Lagrange points at a greater distance from the secondary (lower-mass) body in an orbital pair.
I'm not sure what the situation is for highly complex orbital systems as with Jupiter and Saturn in which there are many moons which might peturb orbits near other planet-moon Lagrange points, though I suspect that these would still be reasonably well-defined for some of the larger moons of Jupiter and Saturn.
For a good visual explainer, see: https://yewtu.be/watch?v=Gu4vA2ztgGM
I am curious about Mercury's Lagrange points. Per the video, they should theoretically exist ... but have astronomers observed natural satellites at those locations, like the corresponding points for Earth or the Jupiter trojans?
Good call.
https://carnegiescience.edu/news/old-plates-new-data-mysteri...
If a much better telescope comes along or an especially dynamic phenomenon is discovered there might be a temptation to take more pictures of something that has already been captured, but otherwise, why would you? This data is expensive and will probably remain so for quite some time, for the obvious reasons.
Seems like an aggressive estimate. For example the Kepler spacecraft produced a lot of data for its planet finding mission. The light curves that it sent back had some automated processing, but had multiple rounds of inspection for identifying the "objects of interest" and then confirming actual planet candidates. The backlog was on the order of a year to when data was taken. This had the additional complexity that to confirm a planet transit you really had to see it pass in front of the star twice to confirm the orbital period.
JWST will also be delivering similar data over its lifetime, but I would assume that ground processing of that data will significantly improve over that timeframe.
https://space.stackexchange.com/questions/57255/why-doesnt-j...
Insufficient fuel means not remaining on station. There's probably an end-of-life contingency to push the telescope "over the top" as EOL is approached, such that it transitions to an independent heliocentric orbit rather than endangering other L2 missions or returning (eventually) to Earth along an uncontrolled trajectory.
A considerable portion of the cost and risk comes from getting the mass and physical size down so we can launch them.
https://webb.nasa.gov/content/about/faqs/faq.html#serviceabl...
With future tech and more research, we will be able to use the fuel it has far more effectively.
the theoretical fuel use is zero... The actual use is proportional to how our calculations of orbits and stuff differ from reality.
At what point do uncertainty effects (limits to measurement precision) and risk (danger of rolling "over the top" of the L2 point, and requiring reverse thrust, which JWST cannot deliver) come in to play?
L2 point is unstable, so theoretical fuel use cannot be zero I believe.
In addition, it uses propellant for orbit position keeping (station keeping) as you wrote.
It does actually have reaction wheels to control attitude without propellant, but it needs fuel to unload the momentum. It's possible the JWST could get into a situation where electricity wouldn't unload the momentum fast enough.
https://en.wikipedia.org/wiki/Spacecraft_bus_(James_Webb_Spa...
https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-m...
All these things necessitate expending some fuel for station keeping.
It's like standing a sharp pencil on its tip - the slightest disturbance causes an accelerating fall, so it always falls. In the case of L2 any object placed there will always drift away with accelerating velocity.
To counteract this you need thrust, and that needs reaction mass. You can't do it with gyros etc, you have to chuck something out in the opposite direction to the way you want to push.
Edit: Incidentally (again not an expert) this sounds like maybe a useful quality of L2. L4 and L5 are stable which I assume means they're filled up with space garbage and odd socks, which maybe would be a problem for putting things there?
It also needs propulsion for attitude control. It does have reaction wheels, but once those are saturated you have to spin them back down. The only way to do that without transferring all that momentum back to the rest of the spacecraft is to use propulsion to counteract it.
Anyone else with this problem? I'd really like to stop thinking these horrible thoughts.
It's the same feeling when you want society to colapse because 'how cool would be to be a survivor in an apocaliptical wasteland'. Or when you vote for a bad candite saying "f..k it, let's see what happens"
Even from purely an entertainment standpoint, the prospect of getting new images from deep space in unprecedented quality and resolution seems a lot more interesting to me than some drama and blame-shifting about billions of NASA dollars going up in smoke.
If you want the experience of a 20 year project dissolving into nothing, you can just rewatch the news coverage about Afghanistan from last summer.
But yeah, it would certainly fit into the string of bizarrely bad news of the last years. Maybe it feels so weird that some project actually appears to succeed for a change?
There are a set of telescope plans which are presently in consideration, including WIRST, the wide-angle infrared telescope; HabEx, the Habitable Exoplanet Imaging Mission; Lynx, a next-generation X-ray telescope; and the Origins Space Telescope, an infra-red telescope even larger than Webb.
https://www.universetoday.com/139461/what-comes-after-james-...
This links as well to a good YouTube video describing each of the proposals.
For telescopes, among factors I'm aware of are:
- The total number of devices. More 'scopes means more points of the sky which can be imaged at any one time. This permits detecting either rare or transient events. There are also possibilities afforded by multiple devices operating in concert, providing both greater positioning sensitivity (angular resolution) and increased surface area, though more the former than the latter.
- Wavelength specificity. Infra-red, radio, visible light, UV, and X-Ray sensitivity all permit detection of different phenomena. Devices suited to one wavelength may not be suitable for others. Specific research goals may favour specific observational methods.
- Other sensing modes. Spectroscopy (which provides information on chemistry of remote objects). Gravity, gamma ray, and particle sensors (e.g., neutrino sensors, cosmic-ray detectors) may afford other options. There are proposals for space-based gravity-wave detectors, for example.
- Compound devices. The HabEx system in particular has two components, the telescope itself, and a sunshield used to block the light of an observed star, which would operate at a separation of 100s of thousands of km.
- Collector size. Larger mirrors permit gathering of more light. This permits shorter collection periods for brighter events, and imaging of previously undetectable phenomena. The Hubble Deep Field views are an example of the latter, and pushed the boundaries of known and and observable phenomena tremendously.
- Storage, processing, and communications capabilities. I don't know how much this contributes to observation capabilities, though I suspect it has an impact.
- Developments in phsyics, materials, and sensing, generally. Looking through lists of physics and chemistry Nobel awards since the 1970s, a surprisingly large number have concerned capabilities rather than fundamental characteristics or properties of matter or the universe. Many of these afford new capabilities in sensing and detection.
- Probes. Rather than a single instrument which views distant objects, probes get close to a specific object, or set of objects, and make close or direct observations of these. Various landers, impactors, flyby, orbiter, and similar missions, to date all to objects within the Solar System, would be examples of these. These compete with other missions (manned, long-distance sensing).
- Earth observation. Probably the largest class and most productive set of space-based observation platforms has been looking at our own planet.
It's also worth thinking through what has made JWST possible, including launch platforms, experience with complex deployments, manufacturing, sensing, and control capabilities. These will have impacts on future missions, and further development might also extend their capabilities.
In situ fabrication or assmbly might offer the greatest opportunity The possibilities of constructing telescopes either in low-Earth orbit and transporting them to an observation orbit, or on remote bodies (the Moon, perhaps an asteroid) also exist. I'm thinking through scenarios in which larger launch craft (Starship, SLS), space-based assembly, and possibly even temporary construction structures --- effectively an inflated balloon in which engineers and technicians could work in shirtsleeve or close-to-it conditions --- might be used to assemble very large structures without relying on the complex deployment ballet used by JWST, or being constrained to the dimensional constraints of the Ariane V launch vehicle and fairing. An asteroid, de-spun, could provide both a shield against solar and Earth-based radiation and emissions, and structure and materials for at least some assembly. This presumes that the asteroid's own orbit would be sufficient for observations and that instruments would be sufficiently aimable from that point.
Finally: most technological improvement tends to follow a sigmoidal curve: an early period of slow development, a period of rapid attainment, then a slower period of approaching theoretical maximum efficacy. New developments or combinations of technologies may restart that curve, but often 15 years doesn't deliver transformational development. Rather older technologies are refined, reliability improved, costs reduced, or flexibility increased. I suspect we'll see a mix of these factors --- some diminishing returns as existing modalities and mechanisms are perfected, and some new avenues as novel combinations do become possible.
"It's around 20 years of propellant, roughly speaking,” though he added that it’s a preliminary estimate.
https://space.stackexchange.com/a/38415
https://time.com/6127003/webb-space-telescope-discoveries/
> Webb faces other operational challenges, however. Hubble has been kept alive in part through maintenance and servicing runs done by astronauts. Webb’s great distance from Earth makes that kind of house call impossible. What’s more, in order to remain stable at its gravity-balanced Lagrange point, Webb needs a thruster system, and a thruster system requires fuel. The telescope will launch with a full tank, but that will be only enough to keep it operating for a minimum of five years and a maximum of 10. In theory, a refill ought to be possible, and the telescope is actually equipped with a docking target to accommodate an incoming spacecraft that could conduct a refueling and extend the JWST’s life. It’s an appealing idea, especially considering the telescope’s dizzying price tag. That spacecraft, however, does not yet exist, though it could within the next decade.
To be honest, sounds like a cool project to start working on, with the idea that it becomes an off the shelf capability for future space observatories. SpaceX's Dragon can carry a 6000 kg payload, and already supports autonomous docking with the ISS, for example.
https://blogs.nasa.gov/webb/2021/12/29/nasa-says-webbs-exces...
Maybe technology will develop enough to allow us to send drones to work on JWST, but today this is still just a dream.
PS: I'm just a random code monkey on the internet, so take these comments with a grain of salt.
Let’s say we wanted a constellation of telescopes to do full sky surveys of small objects in our system for asteroid detection. Do those need to be kept at near absolute zero to be effective at that task?
Webb has a specific mission of imaging deeply redshifted space. I would hope in 20 years we’ll be able to launch bigger, simpler, and cheaper designs for more “pedestrian” missions.
I am very excited about space and the future, I just think that in the years since Apollo the story has been emblematic of wastefulness, contractor level benign corruption (cost plus contracting) more than it has been inspiring with the stories you mentioned. just my opinion.
1 https://en.wikipedia.org/wiki/Budget_of_NASA
2 https://techcrunch.com/2020/03/11/nasas-sls-moon-rocket-is-2...
> NASA's budget peaked in 1964–66 when it consumed roughly 4% of all federal spending....In 1973, NASA submitted congressional testimony reporting the total cost of Project Apollo as $25.4 billion (about $156 billion in 2019 dollars).
I wonder if there also wasn't that level of waste at that point but not too many people cared because the country was mostly terrified by the USSR and wanted to win.
Ironically, I think the more we think there's corruption and waste, the more that may lead to corruption and waste, as we distrust and defund and discourage. Again, I imagine some of the waste comes from the fickle attitude that some of the public and lawmakers have towards funding these orgs.
The stagnation in aerospace is mostly due to us running into fundamental limits of physics pretty quickly, not due to some kind of work ethic or creative failures. to keep pushing forward in space would have required another order of magnitude in funding, and funding during Apollo was already huge. That said, I wouldn't mind if all the worlds military $$$ had been dumped into mars colonization either.
We've sent hundreds of robots all over the place. To Mars, Jupiter, asteroids, comets, the outer planets, out of the Solar System entirely, as close to the Sun as can be managed, and everywhere else in between. For basically all of these missions, sending humans along would be 1000x more expensive, and the humans would be bored to tears for 99.9% of the time. For most of the rest of the time, they'd be relying on the same instruments as the robotic missions, as the environment is too harsh for anything else. So what's the point?
And who would we be sending? We could send super-smart scientific experts to maybe follow up on things a little faster, but it'd be a waste to have them sit around for years on the voyage back and forth. Or we could send more ordinary folks, who might not be all that much more capable than the robots we're sending now.
Sorry, it might burst some peoples bubbles of romance and sexy space adventures, but it mostly just doesn't make sense to send humans into space for the type of exploration missions we're doing. Maybe if we can send enough resources to actually have a colony on Mars or something, but we're not there yet.
What about Voyager, ISS, Hubble, Mars rovers, Mars helicopter(!), and Cassini/Huygens missions? There's more to do in space than just going to the moon. I'd love to see us back there as well, but I think there's still a whole lot to be excited about.
As to what we can do in space: the value of reusable boosters is very understated. Why don't we have a manned mission to Mars? Because it takes a huge payload with lots of delta-V. Sending ten rockets up for orbital refueling was always a pipe dream in terms of cost. Suddenly it's attainable and the solar system is our oyster. It's still expensive, but we now have the tools.
Your comment is really frustrating. few people in this life can do something that was never done before, much much fewer on this scale, much much much fewer with such impact on science and humanity.
So you would have to do that again basically or come up with another mirror design.
I am sure they have learned alot from building JWT, as they certainly learned a lot from building Hubble or the space shuttle. I don't think that knowledge necessarily transfers forwards to make the next project easier.
The evidence is that the time and cost it took to produce JWST are what they are. That planners lowballed these estimates, or that administrators and legislators wouldn't have approved greenlighting based on accurate estimates, speak to failures in planning and administration, rather than engineering.
Much of the planning / large-project literature, which I've studied for some three decades, seems itself to be largely blind to this distinction.
As to many comments found on the Internet mirroring such viewpoints.
20 year project? Dies in committee.
Welcome to politics.
All I'm saying is there's room to improve. JWST would be a monumental success for humanity even if it launched 20 years late.
https://en.wikipedia.org/wiki/Development_of_Duke_Nukem_Fore...
"The video game Duke Nukem Forever spent fifteen years in development, from 1996 to 2011."
This was, and continues to be, a momentous accomplishment.
The fact that it happened at all is a herculean task in constraints management, not only on the engineering side, but also on the political and zeitgeist-management side (e.g., managing different adminstrations with often antithetical perspectives on the value of science, etc).
A lot of folks on HN only see this from their own perspective, of "how-can-I-disrupt-X", or "I would have done it so much better", without a real appreciation of the overwhelming complexities in pulling off a task with so many moving parts (literally and figuratively).
Sure, you could have done it better. Then do it. But don't diminish the value of a truly monumental accomplishment when it happens; they don't come often enough, and more often than not, projects with this level of ambition fail far before they ever get to the point they can be critiqued by arm-chair geniuses.
1. For an astronomer, you can already build such a system yourself quite trivially by getting an large mirror, mounting it in space with a really big catapult, and then using origami to unfold everything. From earth, this telescope could be accessed through everyday ham radios.
2. It doesn't actually replace the Hubble. Most people I know still want to see things in the visible spectrum, and IR fake images just don't cut it. This does not solve the visible spectrum issue.
3. It does not seem very "viral" or income-generating. I know this is premature at this point, but without charging users for the service, is it reasonable to expect to make money off of this?
This is all sarcasm, modified from this infamous comment: https://news.ycombinator.com/item?id=9224
Say it wildly over performs reliability.. it lasts not 20 years but 1,000 years - is that more of success? I'd argue against that - it's more of a failure because we don't need it to last that long.
What if - hypothetically - we had JWST 10 years ago for half the cost but it were just winking out right now? Would that be a failure? I think that's at least an arguable point.
We have that guideline because putting down your peers like this is reliably the marker of a bad comment, and leads to significantly poorer threads. We all love to feel superior to others, or (probably the same thing) to ward off feeling inferior, but this is a low-grade mechanism and never a source of interesting conversation. It also pretty much dominates the internet and we're trying for something different from those defaults here.
HN comments have been overwhelmingly positive about the JWT and it is currently one of the most popular topics that appears here.
20 years is still a rather long time. Expect something else fragile to fail before then. And that's still double the target life time! (And unless they've made it almost maliciously difficult to add fuel, I'm sure there will be some Space Bro who'll offer to refuel it for likes / tax reasons.)
Except we launch well over 1000 satellites a year. The JWT is clearly a bigger deal than that. This has been advertised as NASA's magnum opus. The fact that it was only supposed to last 10 years makes it feel much less significant...
I'm worried that NASA has spent all its money and political will (and then some) getting JWT over the finish line.
I mean, we'll still have some big terrestrial infrared 'scopes. And we'll be coming off 20 years of very good space infrared scope data... And we'll have had the smaller Nancy Grace Roman Space Telescope up in L2 also (launching in 2027, nominal life 5 years).... ESA is launching an exoplanet-focused infrared scope to L2 in a similar timespan... Presumably other "smaller" infrared scopes will fly by 2042. So...
There's so many wavelengths and different possible space telescope missions. Let's not replace JWST (assuming it gets a normal mission life)-- let's keep some infrared capability and do something else.
wonder if we could put a telescope on the moon for $10B though.
Most of JWST's wavelength coverage is energies that terrestrial telescopes can do (just less well). It's not like Herschel which went into the far, far infrared (and had its life limited by liquid He as a result).
Re: Moon-- Why put a telescope down a gravity well?
Most of the discussion of telescopes on the moon I've heard has been about radio telescopes, where a huge hunk of rock between you and Earth can be a feature.
Roman is slated for launch in 2027 (and survived the JWST overruns!), LISA in the 2030s, and there are a few competing proposals that haven't totally firmed up for the next decade too: LUVOIR, HabEx, and a few others
Further optical and gravitational observatories are amongst further options.
Trust that plans are in process.
JWTs location in L2 (a mathematically unstable location that requires energy to not roll back into a gravity well in any direction) is like putting it on the satellite equivalent of K2 and not coming down from the peak for 20 years and you compare it to the thousands of commuters that made it up the hill down the road from your house.
> legally mandated reentry in 25 years.
https://www.esa.int/Safety_Security/Space_Debris/Mitigating_...
FCC subsequently fined them $900k.
[0] https://docs.fcc.gov/public/attachments/DOC-363486A1.pdf
[1] https://www.reuters.com/article/us-usa-satellite-fine-idUSKC...
https://www.hpcwire.com/2019/06/24/a-behind-the-scenes-look-...
Perhaps there's some altrusitic archive.org style site that needs to exist for science, that features datasets of multiple PB in magnitude and allows anyone to pull the full archive.
Maybe in the future, but still, people still have access to source imagery and they regularly make spectacular images and material from public domain data from space agencies and interest groups. You don't need 4PB unless doing something like, well, imaging a black hole.
It's fun, not sure how much there is run a business from it, unless you plan on taking the data and creating spectrographs for some future mining mission way in the future? :D
JWST pivots the entire spacecraft to point the 6 meter mirror. I'm sure they've optimized the consumables on the schedule, but it simply 'costs resources' to do this sort of work. I assure you there are gruellingly dense and optimized observations plans afoot.
Compare to e.g. the very successful Herschel Space Observatory -- it too went out to L2(-ish), did everything it was meant to do in its three year mission, and managed to extend to four before (drum roll) running out of fuel, this time for cooling. JSWT solves this cooling issue by some incredibly funky mechanical resonance cooling. Herschel "only" cost about $1 billion, and it will be interesting to compare the science results.
L2 is an unstable orbit and needs constant corrections to not drift away, so JWST has much more significant fuel needs than if it were in say Hubble's orbit. How much fuel it would have left for these maneuvers depended on how precise the launch was (i.e. how much fuel it needed to spend on corrective burns just to get to L2). This was obviously uncertain until after the launch, but ten years was a lower bound above which the launch would not be considered a major issue--if it only had say 5 years of fuel left after the launch that would be an indication that the launch was flubbed some how.
TLDR: JWST was not "supposed" to last only 10 years. It was designed and built to last much longer, that was just a lower bound assuming nothing went very wrong.
cf. Mars rovers operating long past the "planned" mission length, e.g. Opportunity's "planned" 90-day mission turning into over 5,000 days. It is vastly unfair to the people who designed and built Opportunity to say it was "supposed" to last only 90 days. It was built to last much longer; 90 days was a lower bound for the mission to be considered a success.
This one is hundreds to thousands of times further out than any of those satellites, for instance. It also has a far longer lifetime compared to the average, even before this news. Four times the distance of the moon from Earth. There's no luxury of being able to repair, service and refuel such a thing without approaching or exceeding the costs of just making a new, better one with the learnings and savings from before.
(edit - the "earth moon" distance isn't to scale with respect to planetary diameters... the distance from the earth to the moon is about the same as the sum of all the diameters of all the planets - that's a long way itself)
Or do we get to go all the way back to Shuttleworth, Tito, and Branson?
Surely Branson is the first space bro.
Maybe a new kind of blockchain: https://news.ycombinator.com/item?id=26117587
"After some years of running, any particle physics experiment typically begins to suffer from diminishing returns: as the key results reachable by the device begin to be completed, later years of operation discover proportionately less than earlier years"
Perhaps the same applies to space telescopes too?
> Perhaps the same applies to space telescopes too?
That's not to say we'll run out of interesting things to look at. Only that there is in fact a case of diminishing returns and interest.
But yes, space is big. And there's much in it.
Only stable - self correcting - are L4 and L5 points .
Even if it was stationary at L2, Earth wouldn’t completely shield it from the Sun - the point is too far from Earth/the Sun so large for it to.
There is a nice animation on https://webb.nasa.gov/content/about/orbit.html
Rather than lament its lifespan, I am hopeful that a couple decades from now we will build and launch something that is exponentially better.
Full link, for reference: https://www.npr.org/live-updates/morning-edition-2022-01-11#...
Nobody needs space-mission-ready CRUD that takes $10 billion and 15 years of development.
I see this every day in the difference between SaaS and on-prem Enterprise software. If you have a bug in on-prem, Enterprise every customer needs to deploy the patch. You need to update all affected, supported versions, etc. In SaaS, you just deploy and more often than not that's it. This changes the way you do everything and it comes with a high cost. JWST is the most extreme example on this spectrum.
I was hired because during failovers, the engineers were often getting unhandled runtime exceptions in the failover python code. (much of it was untested except when running failover) Often, the engineers would break one thing while cleaning up another thing. All of this was OK, because the system failed infrequently enough and was eventually replaced with spanner.
If a pure software project would get that kind of money people probably would feature bloat to infinity. The JWST during its design phase were under very strict limiting factors. Volume limit, mass limit, power limit, etc. Compared that with any software project where obviously there are limits but they are much more malleable. You can argue that we need to provision 20% more servers to achieve our goal, but you cannot argue that we need to stretch the Ariane 5 by 20%. (Well you can argue, but the rocket is not going to get stretched.)
So all in all, it seems I'm agreeing with you. But I don't think it's about the quality or grownupness of the participants, but more about the shape of the problem.
I think the modern computing world instead is not grownup, but rather CADT (cascade attention deficit teenagers). A constant developing of new solutions that copy previous ones, but are typically worse, or have the same problems as the previous ones. This seems endemic in the industry, albiet with exceptions.
Anybody who wants to learn more should read the RISKS mailing list and its archives. It's remarkably hard to produce reliable software but a number of groups around the world can do it.
Examples I can think of: the teams that built the series of ESS for AT&T. The folks who built Erlang (telecom reliability is a common theme here, being one of the other technical areas where software and hardware engineering excellence greatly exceeds that which we see from typical groups today). Even Qt, although the quality of their code and its adherence to the principles that make Qt great is variable, I'd say is a good example of a system built by grown-ups.
BTW, when i say "grown-up", I don't really mean anything directly related to age, although age and experience are the best proxies for grown-up. Grown up is really a way of saying: working with more weight on wisdom as raw intelligence (Ghemawat's law), respecting experience even if it's not obvious why you should, (Chesterton's Fence), using statistical testing techniques effectively for quality control (Shewhart), practicing discipline to ensure long-term compatibility and not burning your dependents (jwz's law of CADT). I don't think there's a general term for acting with these principles, I just mentally associate them with being a grownup who has learned from experience.
Yes, totally second that, that's the best school there is, seeing what goes wrong and what the consequences are. I probably spent weeks just reading and analyzing the various posts there.
As for the part of the industry that isn't grown up: anything that can do OTA or automatic updates is likely to suffer from a rash of bugs and usability issues, which includes everything that's SAAS and almost all application software with the exception of some industrial stuff. There is far more low quality software than there is high quality software.
Perhaps a better question would be - for public or enterprise facing projects of similar budget, why is the perceived $X/$Y/$Z so much lower? That is a discussion worth having, and can help unpack your bias and assumptions into a worthwhile conversation.
In short, the expansion of the web economy has allowed for incredibly lazy programming, being done by minimally qualified people, mostly motivated by short term gains, who consistently forget the expensive lessons of previous generations. The original web technologies were fairly good- HTTP and HTML both addressed a need, and I think they were sound (never liked html's derivation from sgml, though, and I don't agree with HTTP's decision to be stateless) but so much of what's sprung up since has evolved with no real natural selection.
"Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something."
It's completely correct to say that modern software development has evolved into clown cars and that big infrastructure projects are run to far higher standards.
Also, why can't I downvote your comment?
You can't downvote a reply to your own comment.
The issue isn't how correct you are or aren't. The issue is comment quality. Your comment was low-quality regardless of how correct you are, or feel.