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With Fuel Exhausted, NASA Retires Kepler Telescope (space.com)
ewhac writes: NASA today announced that it is retiring the Kepler telescope after nearly ten years of service -- double its initial mission life. In that time, Kepler discovered over 2,600 exoplanets, most of which are between the size of Earth and Neptune, sparking an entirely new field of astronomical research, and revealing for the first time just how common exo-planetary systems are. With its fuel supply exhausted, Kepler is no longer able to maneuver or reorient itself to make observations. NASA has elected to decommission the spacecraft and leave it in its current, safe orbit away from Earth.
Why not refuel? Would the cost of a refueling mission be greater than a whole new telescope?
For Hubble, maybe. But Kepler is currently 187 million kilometers behind Earth on a heliocentric orbit and drifting back at 31km/s. Nothing we had, have or will have for a long time can reach there to do a refueling job. It was designed as a sacrificial instrument from the start.
Trying to become famous by taking photos. Visit my homepage please.
Congress wouldn't pay for manned space flight.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Farewell and thank you for a job well done. It's important to remember to count all the victories and remind ourselves at how good it can be. Who would have thought that astronomy would be a hot field? But with better eyes and better thoughts we can peer deeper into the inky blank and make better sense of what we're seeing. Human advancement is possible. The stars are ever closer. Thank you Kepler.
Or what if we would have included an packed solar sail to jettison the probe towards the nearest planetary system detected by Kepler? Just for the fun of it, of course. And to test some equipment while we at it.
Cost of maintaining shuttle programme: fixed costs plus cost per shuttle. Kicker: the fixed part is very, very non-trivial!!! An operational shuttle is not something you just keep around.
Secondly, it is well known that the shuttle design was a compromise of so many "things" it was supposed to do, that it was never anywhere near the original ambition of having something you could land and then just fly again, and is seen by many as a bit of a failure. Just search for "space shuttle bad design" and you'll get many hits.
Thirdly, I'd say that if they had kept the shuttle programme going, it would have stifled some of the innovation we are currently seeing.
As much as I would like to have shuttle capabilities, it was always a dead end in terms of being a platform for going further into space exploration.
Kepler is 137 million km from Earth. About a million times too far away for the space shuttle to get to,
With "its fuel supply exhausted", NASA has "elected to [...] leave it in its current, safe orbit". If you have only one option, seems to me there is not much electing to be done ...
The old shuttles, whether USA or Rusian, would not be able to reach the Kepler. It is verrrrrry far away from earth - millions of kilometers.
NASA's estimate for such a journey is 16-20 years.
Such a probe could return in a viable length of time. Easier than transmitting data 4.1 light years and you'd get better bandwidth.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
A DSV-1 with suitable payload could get there.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
The shuttle couldn't come close to reaching this, it would take an Apollo-level manned mission to even get there.
A DSV-1 with suitable payload could get there.
At great cost with money that should go for the next generation of spacecraft.
Look, Kepler served its purpose. It confirmed over a thousand exo-planets, and thousands more unconfirmed. It is not particularly useful to find a few hundred or even a thousand more. Kepler has been in space for 10 years, and was built with tech even older than that. It is time to move on.
We need a NEW spacecraft that can detect smaller planets, planets further from their star, and even exo-moons. We need to be able to look for spectroscopic signs of O2 in star-crossing exo-planets, which may mean life. Spending $500M on a refueling mission will accomplish none of this.
If we only had a craft able to fly up there and refuel and fix/upgrade it... oh wait we DID! NASA really should have kept 1 space shuttle for just this kind of mission. Sigh. Oh well.
Dude the shuttle couldn't even get to 5000 km above the earth. Kepler is more than 100 000 000 km away. There is nothing we had, have or will have in the near future that can go that far away fill her gas tank and come back.
Nobody has any theory for how to make an interstellar probe return. Any solar sail that can manage to keep accelerating long enough to get up to an appreciable fraction of the speed of light will have no prayer at stopping, because solar sails only work within star systems and it'll be going so fast it'll pass through the star system in far, far less time than it spent accelerating in ours. You need an equal amount of time in the same energy conditions to decelerate as you had to accelerate.
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THANKS BRETT BUTTFUCK
It's like taking your wife's mother out to the forest and leaving her. Justifiable or not, it is a KILLING, homicide in the case of your mother-in-law. In Florida it is known as the stand-your-ground law.
Yeah, you'd have to include the ability to do a 180 halfway along your journey (assuming stars with equal output); definitely a deal breaker.
finally being airlifted/dropped off, at the grand matage casino... out back, near the employee tents..
Considering Kepler found 2600 exoplanets (maybe a few more will be found in exising data) by looking a small sliver of the sky, more advanced telescopes looking at different parts of the sky will certainly yield even more worthwhile discoveries.
If we only had a craft able to fly up there and refuel and fix/upgrade it... oh wait we DID! NASA really should have kept 1 space shuttle for just this kind of mission. Sigh. Oh well.
It's almost as if you don't know where this thing is orbiting.
Clue: Shuttles aren't designed for deep space missions.
No sig today...
I like how you put that last part in bold.
Wall-E will find it eventually, along with the rest of the space junk.
We have a replacement, it's called TESS https://tess.mit.edu/ It's not quite the same as Kepler, but has a similar mission. Good news is TESS's imaging sensors cover a LOT more area than Kepler.
I.e a period of a little more than a year but roughly the same as earth's. That's a reasonable place
to leave it. If it were in an Lagrange point it might be worth not junking that location up for
future missions, although I'm not sure enough of scale to know if that even matters.
How 'big' is the useful area around L2 anyhow?
What planetary system could be reached within 16-20 years? The closest one is over 4 light years away. The fastest we have even sent an object is 0.000135% the speed of light.
Why does it need to use fuel at all, when it could use gyroscopes?
Erm, if nothing we had can get there, how did Kepler get there in the first place? Surely we must have had something to get it there in the first place.
Wouldn't a Falcon Heavy be able to send something to that orbit, as it has proved it can send a payload to Mars?
I love it.
It joins all the other drifters and landers spread around the solar system.
Hopefully whoever finds it puts it in a museum or collection, and not a junk pile.
It seems like there are some theories about how to slow down, at least if you're aiming for the Alpha Centauri system (which is a 3 star system).
"I have never let my schooling interfere with my education." - Mark Twain
But Kepler is currently 187 million kilometers behind Earth on a heliocentric orbit and drifting back at 31km/s
I don't know the accuracy of that statement made by brucetheloon, but if correct, that's how. We put it into an orbit around the sun, and then we slowed it down a little, and over 10 years it's been drifting back behind us. If in 10 years it has managed 187m km, and the circumference of earths orbit is 940m km, we should be able to reach it in about another 40 years.
Kepler is way out of the shuttles range.
Besides the shuttle ability to do such things was over exaggerated, and a normal rocket design could probably do such safer and cheaper then the shuttle.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
Alpha Centauri is 4 light years away. The fastest probe we have ever sent goes 0.023% the speed of light. That means it would take 17,000 years to get there. So unless there is some magical technology that can make probes faster, we don't need to worry about slowing down.
Instead of decommissioning it, why not open it up to amateurs? They won't mind where it's pointed for the chance to play with it...
Show me on the 1st Amendment bobblehead where the moderator touched you...
It's called Daelecious (or something like that--my spelling is rotten) yielding 7% of c.
and is seen by many as a bit of a failure
NASA is either terrible at estimating their equipment lifetime or good at keeping positive press by publishing an expected lifetime much shorter than the real lifetime.
The glass is twice as big as it needs to be.
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Claims of exceeding the initial plans look much better than "oops, we didn't provide for refueling".
Managing expectations is the key — remember, for another example, the Mars vehicles? How every report about their adventures included a reminder, that they've exceeded expectations and therefore we ought to welcome whatever results we got from them, instead of asking, why this or that subsystem stopped functioning...
Excellent PR-job, NASA. The private sector, often blamed for planned obsolescence of consumer devices, ought to take notice. If your iPhone still works after one year, that is a wonderful feat of technology — quit whining, rejoice, and pay us for a new telescope, er, phone.
Yes, enforcing laws, defending borders, and searching for exoplanets — exactly the things government is supposed to be doing...
In Soviet Washington the swamp drains you.
I think you're missing a big part of this discussion. :) It's about using a lightsail to accelerate a tiny probe up to a significant fraction of the speed of light using Earth based lasers. See the Breakthrough Starshot initiative. The discussion was about the difficulty of slowing down on the other end.
"I have never let my schooling interfere with my education." - Mark Twain
I think it would be interesting to just leave it's instruments turned on and create a feed where amateurs could pull down the data and look at it.
Or that NASA is good at over-engineering things so that they complete the mission objectives. If Kepler didn't last as long enough to complete the initial mission time, would the US government and the people keep funding them?
If we take the example of the Mars rovers Spirit and Opportunity, NASA (and no one else) knew what the climate of Mars would do until they sent the rovers. The main concern with the rovers could be engulfed in dust storms for weeks as soon as they arrived. So they overbuilt the battery system to guarantee that the 4 month mission could be completed under the worst conditions.
Another factor is that Kepler and the rovers where never designed to be serviced so everything has to last as long as possible with no hope of service.
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Over-engineering is when you pay $350Bn but you needed $200Bn to finish the mission. That's waste.
Efficiency is when you need to pay $200Bn to finish the mission and you pay $210Bn to get twice as much out of it.
NASA has a record of claiming that things like the Mars Rover are performing amazingly, and that they don't understand how it's been able to keep going so long. They should have a risk profile that shows e.g. 50% likelihood of meeting mission objectives at $200Bn spend, 95% at $250Bn spend, 98% at $252Bn spend; and also, a graph of likely mission opportunities (e.g. extended operating lifetime) at each spend level.
In other words: it's perfectly okay to say you built this to have a 98% chance of completing the mission and that there's a 50% chance of going an extra 2 years and a 20% chance of going an extra 5 years. It's deceptive to say you built this with an expected lifetime of 5 years and holy shit it's still going strong at 15 years! An expected lifetime of 5 years could be that you had a 6-month variation, and could be 50% likely to make it to 5 years, 90% likely to make it 4.5 years, and 10% likely to make it to 5.5 years. It could also mean that you had a 50% chance of failure by 5 years and a 10% chance of failure by 6 months, so you built it to have a 5% chance of failure by 5 years--and it has about 50% likelihood to make it 8 years and a 10% likelihood to make it 12 years.
That all sounds fancy, but it's standard. More than that, it misses the elephant in the room.
NASA didn't build Kepler or the Rover to last a few years before breaking down from component wear.
NASA built them to outlast their mission, and provided fuel expected to exhaust in the mission time.
NASA claimed this truck got 12mpg, fueled it up with a 35gal fuel tank so it could go 420 miles on a tank, and got 1,050 miles out of the tank because it actually goes 30mpg. WTF?
It turns out the tank only needed to be 14gal.
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It's not like there have been any significant improvements in digital imaging, low-power processing, attitude and position sensors and miniaturization in the decade since Kepler and the iPhone 3G were built and launched.
fencepost
just a little off
I'm not disagreeing with that.
I've pointed out elsewhere how to build a telescope capable of spectrometry on Earth-sized planets hundreds of light-years away. Getting a lot of flak for pointing it out, I should add.
So that's the choice. An obsolete telescope we technically can refuel but probably shouldn't, and a space-based interferometer capable of everything you asked but is utterly rejected and despised by many on Slashdot.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Solar tacking, duh.
The fastest probe we have ever sent goes 0.023% the speed of light.
The fastest we have even sent an object is 0.000135% the speed of light.
So which is it?
The fastest we have even sent an object is 0.000135% the speed of light.
The fastest probe we have ever sent goes 0.023% the speed of light.
So which is it?
You have two solar sails.
Remember, the equations most balance, so you have a solar sail for going out, which you discard when acceleration approaches zero (as galactic winds will essentially act as a brake) and you open up a second solar sail facing the other way when you reach the equivalent point in the other solar system.
You now degenerate to zero, since the total momentum exerted in each direction must now be equal and you started at zero.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Why? You have two sets of solar sails, one facing one way, one facing the other.
You don't need the ship facing the other way. The ship isn't doing anything useful, it's space not water.
You open up the first set on leaving, jettison when it ceases to be useful, then open the other set at the equivalent point in the other system.
0 + X - X = 0
Repeat the process for the return journey.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
NASA calculates a solar sail could accelerate a probe to 0.25 C.
That fast enough for you?
If you want to tell them they're hopeless at engineering, go right ahead. That's between you and them, though.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
I'm going by a 1989 NASA calculation for a solar sail.
They reckoned that you need 1 square km of sail per 10g of probe, but that you could reach a quarter light speed by the time you exited the solar system.
Since the fall off of energy follows the inverse square law, and the mass will increase due to dust and other debris accumulating on the sail as a function of velocity, it seems reasonable to assume that if their 0.25C is correct, you'd reach more than that half way (since you'd have much less than half the dust and much more than half the energy).
It takes about 17 hours for a signal to travel from the heliopause to Earth. If that's the edge NASA was using, it would take the aforementioned probe 5.7 days to reach it, which can't be right - the sails can't get enough energy in that time.
They might have been using the Oort cloud, which NASA's website describes as an edge of the solar system. In that case, you're looking at about a light year. That means under 8 years to get there, although most of that distance will be over 1/8 C.
So you've 2 light years to go at 0.25C (8 years travel) the 1 ly at either side. Let's say that's averaging 1/3 C. So that's 6 years on either side, bringing us up to 22 years. We're probably averaging more than that, since it's not linear acceleration. That's how you get down to below 20.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Interesting, but a return means it has to slow down again in our solar system which is a couple of stars short of the requirements. And the 4.6% of C limit means we're looking at a nearly 200 year round trip, which is a lot harder to secure funding for than a 50 year trip some people will actually live to see the results of.
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The whole problem with your premise is that it requires omnipotence and premonition. In hindsight you can claim something wasn't efficient when it exceeded the original goals but back when these things were launched no one had any knowledge of the future in how long things would last.
NASA never claimed one iota of what say they claimed. Instead NASA was given clear mission parameters and a budget which they had to meet. In the specific case of the rovers they didn't know the severity of dust storms or how badly it would degrade battery charging. The worst case scenario had to be used to design the system.
Opportunity has possibly suffered the worst case scenario that NASA planned more than 16 years ago: an intense dust storm has possibly drained the batteries to the point where the rover is likely dead for good. It just took 16 years for it to happen.
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There is a difference between putting a sedan-sized object in orbit around the sun, and hitting an existing sedan-sized object currently in orbit around the sun.
Or for a baseball analogy (I know, I know, tradition is car analogies), it is easy for a batter to hit a ball 500 feet. It is much harder for a batter to hit a ball 500 feet and have it land in the exact same spot as the first.
utterly rejected and despised by many on Slashdot.
NASAs research priorities and budgets are not set by the Slashdot consensus. So what does it matter what people here think?
The whole problem with your premise is that it requires omnipotence and premonition.
Dude I have certification in a field centered around this, and I don't have certification in the specific KA for people who took extended study in estimating. Yes, there's actually certification specifically for estimating, and for risk management, and a number of things.
In the specific case of the rovers they didn't know the severity of dust storms or how badly it would degrade battery charging.
The Rover should have had a more-detailed analysis. NASA was actually pretty accurate with their predictions of its lifetime; they had anticipated dust buildup on the solar panels, and the dust storms were actually cleaning the solar panels, which caused the discrepancy.
Space vessels are a different matter: NASA has plenty of experience getting them into space and operating them in space. They know the power drain and the conditions of operation. It'd be nice if there were some fuel left over after launch, except the launch stages drop off the probe and so that extra fuel is lost. This leaves NASA with a pretty good idea of exactly how much fuel they have once they get into space--and, besides, once they're in space they know how much fuel they have and can re-estimate from there.
That means NASA should be able to predict space vessel lifetimes pretty well. They're built to exhaust their fuel source, and NASA knows how long fuel lasts. NASA knows the operating conditions and the fuel demands. At some point, NASA should be able to determine the probe's lifetime, rather than calling it at 5 years and having half the fuel left at 10.
The same is, again, not true of things in orbit which we repair. We end up extending their lifetimes by intervention. This is also why nobody can predict how long a car will last.
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Dude, so you knew 16 years ago how dust storms would affect both rovers over the course of the next 16 years? Why the hell didn't you tell NASA so they didn't have to design to the worst case scenario?
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Mission parameters of Pathfinder: 1 month
Actual mission duration of Pathfinder: 3 months
Pathfinder didn't give NASA an entire year of data much less a decades worth to determine charge rates, cleaning etc. Remember extrapolation (which NASA had to guess) != interpolation.
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They didn't just design for the worst-case scenario. They overbuilt.
What's your excuse for NASA not being able to figure out how much fuel long-term space probes consume?
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You don't seem to understand anything about estimating. Pathfinder gave NASA ground data to correlate with telescope data, enabling them to model the Martian atmosphere--that was the point. The biggest miss on Opportunity was predicting a continuous coating of dust on the solar panels, which didn't happen at all.
A month is enough to get a read on insolation at ground versus in space versus weather, by the way, so NASA has a pretty good estimate of year-long insolation data, and can work out charging rates from that to relatively-high accuracy because they have a lot of data about how atmosphere interacts with insolation. They also knew a lot more than you do about batteries, and estimated a shorter battery life and higher wear.
As to extrapolation versus interpolation, most estimating isn't exactly that. A lot of estimating is "A is like B, and X is like Y except smaller/bigger and made with B. We've been using a new technique to do C, which is completely-unlike B, but should apply to parts of the process of doing B, so B should be improved in budget and time by these factors. Doing X should thus come out in this manner. Here's the time, budget, and resources necessary." We've never done anything like this, but we know about how much it should cost and how long it should take--and what the variation is in our estimates (i.e. risk).
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You don't seem to understand that one month of data isn't enough to predict 16 years worth of data. Can you use one month of data here on Earth to forecast 16 years? Hell no. Yet you think you can magically predict weather on another planet where we didn't have detailed data.
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So your answer really is you didn't have the slightest clue about the future. So what I said before: NASA doesn't have omnipotence. Funny how that applies to everyone.
As for Kepler fuel, you do understand that most things are designed with a 2X safety factor right? Kepler's original mission was 3.5 years. 2X would be 7 years; however, in 2013 (4 years into the mission) failure of a 2nd reaction wheel meant that mobility of the telescope was limited. Thus they didn't use as much fuel as they would have used if the wheels kept functioning.
In other words, Kepler was fully functional for only 4 years or so. NASA has been able to work around the failures for the last 5 years by refining what it could do. Which means you were basically dead wrong about Kepler.
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That doesn't make any sense. All other things equal, if a star can accelerate a probe with a solar sail to a certain speed away from the star, the same star should be able to deaccelerate the same probe back to the speed it started at when it approaches the star.
Of course, a few things that might make it unequal is that we could bounce the probe around our solar system and sling it around some planets to give it a boost (and the probe would get a boost simply because we would launch it from Earth which itself is moving). We could reverse that in the target solar system but pulling that off might require knowing more about the characteristics of the target solar system than the data we'd have at launch.
Another factor would be how luminous the target star is - a star less bright than the Sun obviously won't be as effective at slowing the probe down than our Sun would be at accelerating it. But that could be used to our advantage in the case sending probes to stars that are more luminous than the sun.
Any solar sail that can manage to keep accelerating long enough to get up to an appreciable fraction of the speed of light will have no prayer at stopping, because solar sails only work within star systems and it'll be going so fast it'll pass through the star system in far, far less time than it spent accelerating in ours. You need an equal amount of time in the same energy conditions to decelerate as you had to accelerate.
So either dive into the sun at the target system or do what Robert Forward suggested:
https://arc.aiaa.org/doi/10.25...
The weather patterns weren't unusual and unpredicted; the probe's performance given those patterns was.
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Extrapolation is not interpolation. Someone with the credentials you claim should know this. One month of Mars data doesn't begin to cover all the seasons of Mars. And all 4 Mars seasons take about 1.8 Earth years. I can't see how anyone can claim one month is enough data.
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