Hacker News Reader

Comment by kunai | Hacker News Reader

One of NASA's biggest mistakes wrt the demise of the STS/Shuttle program was not leaving some way lined up to service Hubble in orbit. The current crop of launch vehicles isn't suited to this task, despite us being ten years out from STS-135.

It's proven itself an absolutely invaluable tool for research, but I think the even more impressive mission Hubble has shown itself as irreplaceable for is stimulating the public's mind for science and exploration. There's nothing like seeing photos of the universe in visual-light spectrum and thinking, "what if we went there?"

JWST is amazing and I'm so glad it's finally launching but for that second use case, it trails Hubble.

View on HN

I wouldn't lay the blame on NASA. Congress ultimately decides what NASA does and does not do.

Constellation was the system that was supposed to succeed the Shuttle. It had one successful first-stage launch in October 2009. In 2010, Constellation was cancelled by Congress (at the behest of then-president Obama). In its stead, Congress essentially designed a new rocket called the Space Launch System, and tasked NASA with building it. Constellation's crewed capsule, Orion, survived as the SLS's crewed capsule. Unfortunately, the SLS is now 5 years overdue for its first launch. (It currently seems reasonably likely to launch for the first time in 2022.)

The Orion capsule could conceivably service Hubble [1], especially after lots of launches and general experience with the vehicle. If Constellation had not been cancelled, or if Congress had tasked NASA with a less-ambitious rocket to build, (or if the contractors that NASA was obliged to use to build the SLS had been able to keep to the original schedule,) we might have had a spacecraft to service Hubble right now.

[1] https://www.thespacereview.com/article/3965/1

I think JWST will be an amazing replacement as most space photos are doctored with visible light "interpretations" of other wavelengths already and nobody seems to notice/care as they have their minds blown. The process almost even adds to the beauty of them.

>nobody seems to notice/care as they have their minds blown

Some people do, and erroneously conclude that "space is fake". This would be laughable, if not for the part where they then persuade their friends and family to feel deceived. Artificially coloring images without disclosing it clearly upfront in a highly visible manner, ideally with some sort of watermark on the image, is the sort of white lie that contributes to the public's growing distrust of authority.

Yes, I know the caption below the image usually disclaims it. But as you say, most people don't notice or know it until somebody points it out to them, and too often the somebody who points it out is somebody who's peddling nonsense of their own.

Calling it "doctored" is perhaps a stretch. Hubble (and many earth-bound astronomers) take images of emission nebulae with narrowband filters covering some of the emission lines that are important and particularly strong. The typical ones are hydrogen-alpha, oxygen-III, and sulphur-II. These are particular colours of light that are emitted by these chemical elements, and so detecting these emissions are the best way to detect these chemical elements, for science.

Then these detections are put together into a false-colour image so we can visualise it. We have three narrowband filters, so it makes obvious sense to map them to the three primary colours in the image.

It's not about using weird filters on the telescope to make "doctored" images that look impressive. It's about using weird filters on the telescope to collect the best science possible, and then using that data to make an image.

How do you visualize non-visible wavelengths except by using visible wavelengths? I mean, for humans.

You basically use a mapping function that assigns a visible wavelength to a corresponding non-visible one. Its as if you're manually red-shifting the light "down" the spectrum.

What will they think of next?

That's a good point. Regardless of how it shakes out, I'm really excited to see the first images from Webb. The implications this spacecraft could have for understanding the question of where we came from are immense.

I thought the experience they had servicing Hubble actually meant that they generally didn’t want to have satellites that they would have to service due to costs involved.

Maybe with the new options it becomes cheaper/ more viable.

How was that a mistake? What was the alternative?

For the near term it's always going to be cheaper to launch replacement satellites instead of servicing broken ones in orbit.

Reply on news.ycombinator.com