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I didn't realize the JWT will need to burn fuel in its steady state. Its pretty disappointing that this took 20 years to build and we will only get 20 years of
by dahfizz 5y ago
I didn't realize the JWT will need to burn fuel in its steady state. Its pretty disappointing that this took 20 years to build and we will only get 20 years of use out of it.
- Buttons840 5y agoHopefully the time limit will serve as a kick in the pants to build an even better telescope.
- Sharlin 5y agoLUVOIR: https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infrared_Surveyor https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infr... (basically a bigger JWST but for UV/optical/NIR observations à la Hubble).
- JaimeThompson 5y agoCurrently we can only lift so much mass into orbit which limits such things drastically.
- CabSauce 5y agoHopefully we'll have cooler stuff in place by then. I'm assuming it can also be serviced, like Hubble.
- btmiller 5y agoCurrent plans are for it not to be serviced. Considering that it’s sitting way beyond the moon at L2, it’d have been out of each even for the shuttles when they were still in service.
- Sharlin 5y agoHowever, hopefully it’s not out of reach of the hardware we’ll have in 20 years. Even though right now our capability is actually less than 20 years ago…
- nisegami 5y agoThe JWST was not designed to be serviceable. It's not impossible, but it's not in the plans right now.
- wpasc 5y agoits L2 point takes about a month to reach, much different orbit than Hubble which is why the flawless launch is so important and the unpacking.
- deleted 5y ago[deleted]
- WJW 5y agoNothing is impossible, but L2 is much further away than humans have ever been. AFAIK, we do not have any human rated spacecraft even remotely capable of going that far (and, hopefully, coming back).
- delecti 5y agoIt's unlikely anything at L2 could be serviced until we have significant infrastructure in space (like something for refuelling). Hubble orbits about 400 miles up, JWST is about 1 million miles away.
- toomuchtodo 5y agoJWST was designed for future refueling capabilities (there is a docking target and an externally accessible port for access to propellant storage), and this mission is well within existing launch vehicle capabilities (if a robotic refueler is lifted as payload). At launch, JWST was fueled with ~301 kg of propellant, so subtract that from launch vehicle payload to get an idea how heavy your refueling vehicle can be (assuming roughly 4k-5k kg depending on launch vehicle), and some margin for the refueler to separate and propel itself over the gravity edge JWST balances itself on from L2 into deep space post refueling. https://space.stackexchange.com/a/38415 https://space.stackexchange.com/a/38415 https://time.com/6127003/webb-space-telescope-discoveries/ 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.
- delecti 5y agoBy "servicing" I actually meant more "repair". The initial burns left enough fuel that JWST is likely to wear out before it runs out of fuel. The refuelling I meant was for craft to get people there and back, because repair is significantly more difficult than refuelling. https://blogs.nasa.gov/webb/2021/12/29/nasa-says-webbs-excess-fuel-likely-to-extend-its-lifetime-expectations/ https://blogs.nasa.gov/webb/2021/12/29/nasa-says-webbs-exces...
- nzach 5y agoJWST will be so far away from earth that is unlikely any human will ever get near him. Also, Hubble was designed to be serviceable during its lifetime. This isn't the case for JWST. 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.
- bpodgursky 5y ago20 years is a long time, and space is moving fast these days. I wouldn't bet on it not being serviced (although I do agree that we'll have something better by then).
- jagger27 5y agoIf I were to bet on something it would be a simpler but bigger design that takes advantage of Starship’s much wider fairing. 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.
- lanewinfield 5y agoleave it to hn to be disappointed about such a monumental achievement
- wpasc 5y agoWell, considering the progress in space in reaching the moon and the arguably stagnant (except recent developments like reusable boosters) developments since then, I think it's very reasonable to be disappointed in the past years of space development.
- deleted 5y ago[deleted]
- lapetitejort 5y agoHuman spaceflight has stagnated for sure. However, we have multiple rovers on Mars. We have satellites that tell us exactly where we are on Earth. We took pictures of Pluto. We exited the solar system. We landed on an asteroid. We slammed into a comet. I choose to be excited.
- wpasc 5y agoAll undeniably incredible achievements. I look at Nasa's budget [1] and see the government achieve something incredible in the apollo project and take their foot off the gas on the most exciting (and potentially unifying) frontier. I also look at the corruption and stagnation in US rocket systems like SLS and the sinkhole of hours and dollars it has been [2]. 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 https://en.wikipedia.org/wiki/Budget_of_NASA 2 https://techcrunch.com/2020/03/11/nasas-sls-moon-rocket-is-2-years-behind-and-billions-over-budget-internal-report-finds/ https://techcrunch.com/2020/03/11/nasas-sls-moon-rocket-is-2...
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- 2OEH8eoCRo0 5y agoI was planned to last 10 years.
- verytrivial 5y agoThen you're going to be disappointed by all satellites I'm afraid. They all need to do station-keeping, and have a way to maintain orientation when they spin-down their reaction wheels. "Solar-powered" thrusters use fuel too but use an electric field to accelerate it. 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.)
- musesum 5y ago> some Space Bro who'll offer to refuel it for likes / tax reasons Maybe a new kind of blockchain: https://news.ycombinator.com/item?id=26117587 https://news.ycombinator.com/item?id=26117587
- dahfizz 5y ago> Then you're going to be disappointed by all satellites I'm afraid. 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...
- FourHand451 5y agoI mean, is there something you'd suggest they should have done differently? I'd imagine they gave it as much fuel as they possibly could while meeting all of the other design goals. Is is possible you're more disappointed with the advertising than the observatory itself?
- dahfizz 5y agoMy real concern was the difficulty we had getting the JWT ready. If JWT's successor will also take 20 years to produce, then we better start working on it tomorrow. A 10-20 year lifespan on the telescope would be perfectly fine if we could launch a new one every 5-10 years. I'm worried that NASA has spent all its money and political will (and then some) getting JWT over the finish line.
- enkid 5y agoWe probably will have even cooler stuff up there in twenty years. Also, with the accessibility of space opening up, a refueling mission may become possible.
- anovikov 5y agoMost likely not refueling, but docking with a spacecraft that will provide propulsion. Has been tried with MEV-1 spacecraft docking Intelsat 901 a couple years back. JWST has a docking ring for that purpose.
- willis936 5y agoThink about what the craft is doing. It isn't just sitting out staring at one location. It orbits the Sun but doesn't want to ever see the sun. I bet if we wanted to get extra clever we could do flip maneuvers to preserve fuel, but if JWST hasn't met its goals in 20 years then messing about with time wasting tricks won't help it.
- cfaulkingham 5y agoI would hope we have something better to replace it with before then.
- nemacol 5y agoMaybe in 15 years we will have space drones to refuel it! :D We can dream.
- mongol 5y agoFrom the Wikipedia page of the Large Hadron Collider "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?
- dotancohen 5y ago> Perhaps the same applies to space telescopes too? Not really. The amount of targets that can be explored with JWST would take far longer than 20 years to image. And many targets, such as exoplanets or expanding novas, benefit from periodic reimaging with the same instrument.
- dredmorbius 5y agoThose targets themselves represent varying levels of interest and returns. The distribution of these is all but certainly a power law or Zipf function itself. 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.
- me_me_me 5y agoWeird nobody mentioned yet, JWST is at L2 (permanently shielded from sun by earth). L2 is not a stable and need correction burns to stay there that's the reason for life time of 20 years. Only stable - self correcting - are L4 and L5 points . https://en.wikipedia.org/wiki/Lagrange_point https://en.wikipedia.org/wiki/Lagrange_point
- carl_dr 5y agoJWST isn’t in Earth’s shadow - it orbits around L2 (approximately perpendicular to the Sun-Earth axis) at a radius comparable to the Earth-Moon distance. JWST has a huge solar array used to power the electronics on-board. 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 https://webb.nasa.gov/content/about/orbit.html
- me_me_me 5y agoYou are absolutely correct, it even has a massive sun-shield for that :D
- ricardobeat 5y agoYou should be disappointed that it took 20 years to build, period. Anything that runs for 20 years unattended is a massive technological achievement.
- FredPret 5y agoIf I were a 100-billionaire, I’d finance several of these. There was a fashion among the very rich 100+ years ago to finance ground-based telescopes and have it named after themselves
- paxys 5y agoThink about the state of technology 25 years ago. Are you disappointed that things built back then are obsolete now? Why should satellites be any different? Rather than lament its lifespan, I am hopeful that a couple decades from now we will build and launch something that is exponentially better.
- _b 5y ago20 years of taking pictures, but we'll be able to study the data it gathered, and benefit from discoveries it enabled, for an indefinite amount of time.
- awb 5y agoTechnology advances so fast though. Imagine a desktop from 20 years ago. We’ll be ready for an upgrade long before it runs out of fuel.
- stjohnswarts 5y agoSorry this is a one off unique device. 20 years is a great life in the history of NASA, plus they will most likely have robots that can refuel it in 20 years easily if it's even worth doing with 20 years of advancement in astronomy by then.