NASA releases Hubble image taken in new pointing mode • Hacker News Board

Re: NASA releases Hubble image taken in new pointing mode

#71

Post by FactolSarin » Thu, Jun 20, 2024, 3:12 PM UTC

tempnow987 wrote: post #69

tonetegeatinst wrote: post #7

NASA has such a tiny budget in comparison to other stuff....so they really have to stretch that money as far as they can, and especially considering spacecraft....its a very unforgiving production environment. Am I making a joke about deploying in production? Yes, yes I am. But I also know NASA really does the best they can and I am amazed at the insane work and effort that they do to make sure spacecraft they send a…

Except you look at what they are spending on the entire SLS infrastructure vs what they are getting (vs other science options and/or space exploration options) and basically your mind is blown at how wasteful NASA is. SLS is a $2-$3 billion per launch DISPOSABLE rocket. The orion capsule is going to be something like $20 billion(!). I think things like launch abort and service module with all the propulsion etc are a…

I don't think NASA would have chosen the SLS platform though. It was basically mandated by Congress.

Re: NASA releases Hubble image taken in new pointing mode

#72

Post by _mlbt » Thu, Jun 20, 2024, 3:12 PM UTC

Tostino wrote: post #30

phaedrus wrote: post #21

Earlier quoted context omitted.

I'm sure at NASA as at all government agencies there are teams who work very efficiently and do more with less, and other teams whose mission does not have that characteristic and constraint.

The majority of inefficiency seems to leek into NASA via our Congress.

This isn’t specific to NASA or Congress. U.S. Government agencies will utilize whatever budget they are given, period.

There is no incentive to be efficient. If there is leftover money in the final fiscal quarter you are highly encouraged to use every penny, even if that means buying new furniture and office supplies that you don’t really need. Any leftover money will be given to someone else and you will receive a smaller budget the following year.

Re: NASA releases Hubble image taken in new pointing mode

#73

Post by ijustlovemath » Thu, Jun 20, 2024, 3:13 PM UTC

regularfry wrote: post #14

londons_explore wrote: post #9

Earlier quoted context omitted.

Luckily the processing for this sort of control loop is usually very simple mathematically. It's gonna be a few multiplies and a bunch of adding and subtracting most likely. The challenge is designing that mathematical formula, and making sure to take the readings from the sensors and output them to the actuators on time .

It's not just designing the formula, getting the parameters right is going to be a right pain. You might have meant that as part of "designing" but it's a significant challenge in its own right, over and above having a formula that's the right shape. Not to mention numerical accuracy in the implementation, but I'd assume that's mostly known patterns at this point.

The beauty of using a Kalman filter is that its constantly refitting the model parameters to match the observed state.

Re: NASA releases Hubble image taken in new pointing mode

#74

Post by cubefox » Thu, Jun 20, 2024, 3:15 PM UTC

dr_orpheus wrote: post #50

cubefox wrote: post #32

Naive question: Today, smartphones use microscopic gyroscopes based on MEMS (micro-electromechanical systems) technology. Would these also work on Hubble? I suspect they'd work fine in space, perhaps while also being more durable (the failing Hubble gyroscopes were only installed in 2009). Though I guess their precision is not good enough for a telescope.

The accuracy of MEMS gyros is orders of magnitude worse than the gyros on Hubble. I suspect based on this article [0] that Hubble uses hemispherical resonator gyros (HRG [1]). The really high accuracy rate sensors that you find in spacecraft are usually HRGs or Fiber Optic Gyroscopes (FOG). [0] https://science.nasa.gov/mission/hubble/observatory/design/h... [1] https://en.wikipedia.org/wiki/Gyroscope#HRG

Oh, this made me worried about JWST (as it can't be serviced once the gyroscopes break), but I found this:

> To detect changes in direction JWST uses hemispherical resonator gyroscopes (HRG). HRGs are expected to be more reliable than the gas-bearing gyroscopes that were a reliability issue on Hubble Space Telescope. They cannot point as finely, however, which is overcome by the JWST fine guidance mirror.[18]

https://en.wikipedia.org/wiki/Spacecraft_bus_(James_Webb_Spa...

So Hubble uses gyroscopes that are more precise but less reliable than the HRGs used in JWST.

Re: NASA releases Hubble image taken in new pointing mode

#75

Post by ijustlovemath » Thu, Jun 20, 2024, 3:15 PM UTC

cubefox wrote: post #57

SaberTail wrote: post #49

Earlier quoted context omitted.

No, the comment you're replying to is confused. These gyroscopes are entirely used for determining Hubble's orientation. Reaction wheels effect the actual rotation, and Hubble's are fine. I think the confusion is a result of imprecise language talking about how they are used to slew the telescope. They are "used" but as feedback, in conjunction with other systems. Also, there have some prominent reaction wheels failu…

Thanks, this makes sense. I guess I should look up the difference between gyroscopes and reaction wheels next.

Per your name: https://m.youtube.com/watch?v=n_6p-1J551Y&pp=ygUG

Re: NASA releases Hubble image taken in new pointing mode

#76

Post by zamadatix » Thu, Jun 20, 2024, 3:32 PM UTC

semi-extrinsic wrote: post #64

trentnix wrote: post #17

Earlier quoted context omitted.

NASA looks efficient because you’re comparing it to the rest of government. I love the work they do. I wish they did more with what they have. And then I wish they had more to work with. When they are constrained, like they are with spacecraft already in flight, their ability to problem solve with the tools and systems they have available is absolutely impressive.

> NASA looks efficient because you’re comparing it to the rest of government. NASA also looks quite efficient when you compare it to many tech companies. NASA has 18k employees and $25bn budget in 2023, let's compare it with some companies: Spotify and Stripe are each equal to half of NASA both in terms of employees and budget. Snapchat and Airbnb are both approx 1/3rd of NASA in both employees and budget. Yahoo has…

How do I read this employees/budget metric to properly rank efficiency?

Is 1,000 employees each with an average burn rate per employee of a $1,000,000/y supposed to be more or less efficient than 2,000 employees with an average burn rate per employee of $500,000/y? If so, why is that a sign of an inherently more efficient company when we haven't even mentioned things like output yet? E.g. some of the companies in the list post a large loss, others post a large gain. If a company doubled it's employee count and posted a 10% change in profit due to staffing budgets why should that result in 100% or 50% change in this metric?

Is 1,000 companies with 1 employee each and a budget of $1,000,000/y inherently supposed to be the same efficiency as 1 company with 1,000 employees and a budget of $1,000,000,000/y even if the other company is posting a profit and the small company just spending it all each year?

I'm generally on the side of NASA but in this case I just don't understand how to apply this metric in a meaningful way. It seems almost everything else about the company is more relevant to overall efficiency the "amount of money spent in the last year for a given number of people working there". I.e., at the end of the day in terms of efficiency I don't really care if 1 person works at NASA or 100,000 people work at NASA I care how quickly they get meaningful missions completed at a given budget.

Re: NASA releases Hubble image taken in new pointing mode

#77

Post by dekhn » Thu, Jun 20, 2024, 3:32 PM UTC

cubefox wrote: post #56

olleromam91 wrote: post #47

Earlier quoted context omitted.

The sensor you’re describing is usually called an accelerometer.

No, accelerometers detect acceleration in linear direction (up/down, left/right, forward/backward), while gyroscopes detect rotation (pitch, yaw, roll). Smartphones have both, to detect all six degrees of freedom. Edit: Apparently, for smartphones, all these sensors are integrated into a single MEMS chip, one sensor for each degree of freedom, three accelerometers and three gyroscopes: https://youtube.com/watch?v=9X4…

BTW, smartphone acceleromoters are also packaged for hobbyists; a board like https://www.adafruit.com/product/2019 can be easily used to make any number of applications when coupled with a microcontroller. https://learn.adafruit.com/adafruit-mma8451-accelerometer-br...

Re: NASA releases Hubble image taken in new pointing mode

#78

Post by _joel » Thu, Jun 20, 2024, 3:39 PM UTC

FactolSarin wrote: post #71

tempnow987 wrote: post #69

Earlier quoted context omitted.

Except you look at what they are spending on the entire SLS infrastructure vs what they are getting (vs other science options and/or space exploration options) and basically your mind is blown at how wasteful NASA is. SLS is a $2-$3 billion per launch DISPOSABLE rocket. The orion capsule is going to be something like $20 billion(!). I think things like launch abort and service module with all the propulsion etc are a…

I don't think NASA would have chosen the SLS platform though. It was basically mandated by Congress.

[flagged]

Re: NASA releases Hubble image taken in new pointing mode

#79

Post by el_toast » Thu, Jun 20, 2024, 3:42 PM UTC

FactolSarin wrote: post #71

tempnow987 wrote: post #69

Earlier quoted context omitted.

Except you look at what they are spending on the entire SLS infrastructure vs what they are getting (vs other science options and/or space exploration options) and basically your mind is blown at how wasteful NASA is. SLS is a $2-$3 billion per launch DISPOSABLE rocket. The orion capsule is going to be something like $20 billion(!). I think things like launch abort and service module with all the propulsion etc are a…

I don't think NASA would have chosen the SLS platform though. It was basically mandated by Congress.

Same story with shuttle and that's why it looks the way it is and was as expensive as it was. It would have been a completely different vehicle if Congress weren't meddling.

Re: NASA releases Hubble image taken in new pointing mode

#80

Post by dotnet00 » Thu, Jun 20, 2024, 3:45 PM UTC

fallingknife wrote: post #55

tonetegeatinst wrote: post #7

NASA has such a tiny budget in comparison to other stuff....so they really have to stretch that money as far as they can, and especially considering spacecraft....its a very unforgiving production environment. Am I making a joke about deploying in production? Yes, yes I am. But I also know NASA really does the best they can and I am amazed at the insane work and effort that they do to make sure spacecraft they send a…

There's a billionaire who has offered to do a repair mission. NASA considers this too risky to let some random guy go up there and fix it. If they worked together on a plan I feel like they could get this done in a way that reduces the risk, but it seems like they just don't want to.

It's worth adding that the proposal was mainly for reboosting the telescope, which can still be done later if needed.

Trying to EVA and work on Hubble would be very risky right now with Dragon since you have to vent the entire capsule first, and this creates all sorts of optics contamination risks.

They're also balancing this against upcoming technologies, possible cost reductions and the much improved capabilities of ground based telescopes due to advanced adaptive optics.