How to Ship the World’s Largest Space Telescope 5,800 Miles Across the Ocean | Hacker News Reader

How to Ship the World’s Largest Space Telescope 5,800 Miles Across the Ocean

nasa.gov

I imagine I'm not the only one, but every time I hear/see anything about JWT I just find myself muttering 'please work please work please work' audibly under my breath.

You know it runs Javascript, right? [1] I mean, as long as you're worrying...

(Before anyone starts hollering, I earn my bread and butter in the same language, and that'll be what makes me a millionaire in the unlikely event anything ever does. But on the other hand, somebody's gonna mention it, and I suppose it may as well be me.)

[1] https://www.stsci.edu/~idash/pub/dashevsky0607rcsgso.pdf sections 3.1, 3.5, 4.2ff.

No one would lament JavaScript if every implementation was as robust as the few that go to space.

In entire fairness, nothing we usually work on costs thousands of dollars per kilogram to send somebody to fix it, either.

JWST was never designed to be serviceable, because it's so far away[0]. It would probably be possibe to get a crew to L2 with our new SLS/Orion capability (with costly modifications)[1], but I don't think this was really anticipated back when JWST was designed. And once they get there, effecting a repair would be the equivalent of patching an executable with no source code, in production.

[0]: https://jwst.nasa.gov/content/forScientists/faqScientists.ht... [1]: https://www.researchgate.net/figure/The-crew-segment-of-the-...

> The JWST science operations will be driven by ASCII (instead of binary command blocks) on-board scripts, written in a customized version of JavaScript. The script interpreter is run by the flight software, which is written in C++.

> The flight software operates the spacecraft and the science instruments. The on-board scripts will autonomously construct and issue commands, as well as telemetry requests, in real-time to the flight software, to direct the Observatory Subsystems (e.g., Science Instruments, Attitude Control, etc.). The flight software will execute the command sent by the calling on-board script and return telemetry, which will be evaluated in real-time by that on-board script. The calling script will then send status information to a higher-level on-board script, which contains the logic to skip forward in the observing plan in response to certain events (see Section 4.1).

Maybe NaN will come to mean Not a Nebula

There's CoffeeScript in that nebula.

I am not an astronomer or involved in this project but I am crazily nervous and excited for the launch, orbital placement and deployment of this telescope. It seems sooo epochal and important.

I'm ambivalent. It's crazy expensive and will be cool, but with the improvements in satellite constellations, launch capabilities, and sensor aggregation that are coming out over the next 5-10 years, I suspect we're going to get platforms that surpass the JWST's capabilities much sooner than anyone thinks

Maybe, but that's OK! Hubble's still plugging away doing good science. We'll get platforms better than JWST, but it'll be a while before we've got enough telescopes in orbit to fulfill every potential good avenue of research/observation.

It blows my mind how far this telescope will be.

- ISS is 400 km from earth.

- Hubble is 500 km from earth.

- The moon is 384_400 km from earth. It took us 3 days to fly there.

- JWST will be 1_500_000 km from earth. It will take 30 days to fly to its final position.

Only ~4 times as far as the moon.

If you want to blow your mind more by a few orders of magnitude, Voyager 1 is currently 23,143,000,000 km from Earth. Its taken 44 years to get to that position.

And relative to the galactic center (https://en.wikipedia.org/wiki/Galactic_Center; actually only a galactic center out of many billions), the solar system is about 320,000,000,000 km from where it was 44 years ago.

Not sure if I missed something, why did this have to be shipped across the ocean to a spaceport in French Guinea? Would it have been less of a logistical challenge to launch this out of Vandenberg in CA?

The closer to the equator that you launch the more of an advantage you get from the rotation of the earth. Your starting velocity is higher launching from the equator than from a point closer to the poles of the earth.

It is launching on an Ariane 5 rocket which has the launch facilities in French Guiana (for the reason I mentioned above).

Edit: Vandenburg is also even worse from this perspective because in order to launch out over the ocean, you are launching against the rotation of the Earth so you have to overcome that velocity. But Vandenburg is often used for polar orbits where the rocket launches almost due south from Vandenburg over the ocean.

ah, thanks for that. I wonder if this also explains why spaceports in the U.S. have tended to be located further south.

Yep, that is definitely one of the reasons.

The other significant reason for putting a spaceport further south is the inclination of the orbit (angle of the orbital plane to the equator) is limited by the latitude of the launch site (without a secondary maneuver after launch). So for example if you launch due east (which gives the most advantage of the Earth's rotation) from Cape Canaveral, which is at a latitude of ~28 degrees, you will end up in an orbit with a 28 degree inclination. Launching further North or south you end up with a higher inclination either way. So in order to get an inclination close to equatorial it is easiest to launch closer to the equator. Its a bit hard to visualize but this article has some good explanations [0].

[0] https://www.planetary.org/articles/3450

It’s launching from French Guiana because it’s launching on Ariane 5 and that’s where it launches from.

It’s launching on Ariane 5 because it is a very powerful and incredibly reliable rocket that can carry a very large and customized fairing for this very large satellite that needs to go very far.

Mostly because its a NASA-ESA-CSA joint project. The JWST is jointly built by NASA-CSA. The ESA contribution is the launch vehicle.

I recall it was because of the payload capacity/volume of the Ariane rocket. Maybe there are better alternatives at this point.

Some NASA critic probably has a wonderful "last gasp of the monster" retrospective on this. "Build a telescope years after disposing of any launch methods", "design with no consideration for transport or launch, and so on.

I have heard "The NASA way" called a gold standard of inefficiency. As they fold up operations; who will take over that mantle of ludicrous largess? Not even Blue Origin can gold plate things "just because it looks better that way".

> after disposing of any launch methods

Huh? They had a variety of launchers to pick from.

> design with no consideration for transport or launch

Again, huh? The folding nature of the JWST is specifically a launch consideration; fitting in the available fairing sizes.

> Build a telescope years after disposing of any launch methods

Eh? A variety of launch vehicles were available; they chose the most appropriate one.

none of those launch vehicles were theirs. to me, NASA is less of a space agency as much as a satellite builder/operator. to be a space agency, you must be able to get to space not being to hitch a ride. hell, the Space Force is more of a space agency than NASA.

This makes absolutely no sense and I assume little thought went in to it. From the very start, the Pioneer 1 satellite, NASA has used rockets developed and operated by other entities.

A major, if not the principle, reason for NASA to exist is space science, not rocket science. Their satellites, research stations, etc are seriously important work. The rockets are definitely important, but primarily as a way to enable the space research.

This is like saying an airline isn't a true airline because they don't design their own planes. It just doesn't make any sense.

And then they went on to develop Mercury, Gemini, Apollo, Shuttles. All of them were able to launch payload into space. NASA can no longer do that. They have gone backwards in capability. The launch systems they are working on are so no where near working that multiple other company have been started and surpassed them in that amount of time.

NASA is no longer a space launch company. They service existing missions that were planned/designed/launched when I was kid. This pretty much makes them a legacy. Where's the new?

> NASA is no longer a space launch company.

Good. That was never the point of NASA. If they can contract out the launchers to SpaceX, ULA, etc., they can focus on the scientific aspects. Funding launch platforms via CRS and Commercial Crew was one of NASA's smartest and most cost effective decisions.

> Where's the new?

Quite a bit of it is on Mars actively exploring right now.

> NASA is no longer a space launch company.

NASA has never been a space launch company. Or a company at all, for that matter.

They’re a government administration that always contracted out most design work to private firms, with a mission much broader than space launch.

Who is "they"? You realize that most of the actual development work on all those programs was done by contractors/subcontractors in the aerospace industry?

NASA just landed a highly advanced rover on Mars, with a helicopter that exceeded all expectations. They do new stuff all the time. And do you know how much funding they had during the moon landing era? Even then, the Lunar service module, LM, etc. were developed amd built by outside companies (North American, Northrup-Grumman, etc.). And then there's the political SLS debacle which soaks up so much of their funding.

Oh yes, everything was built by NASA.

Its why components are called:

Rocketdyne F-1, Grumman LEM, North American Rockwell CSM, Douglas S-IVB

I'm not sure it's important that NASA be in charge of rocketry. The fundementals are well understood and private industry is willing to handle it, so why not? As long as the bus exists why does NASA have to own the bus?

JWST isn’t likely the most complex thing launched in space, just the most complex thing that is unclassified.

Yep.

2012: "The secretive government agency that flies spy satellites has made a stunning gift to NASA: two exquisite telescopes as big and powerful as the Hubble Space Telescope. They’ve never left the ground and are in storage in Rochester, N.Y."

Those were just outdated spares predating Hubble, and apparently more advanced: https://www.washingtonpost.com/national/health-science/nasa-...

For some reason those eggheads in labcoats insist we should point this telescope away from earth, can you imagine? What a waste.

They always had a launch vehicle. The JWST is a joint NASA-ESA-CSA project. The ESA is responsible for the launch as part of the project.

I can't wait for the first deep field results from JWST

While this is the largest space telescope it's not the largest telescope - for example the Vera Rubin Observatory optics (also shipped by boat down to Chile) are quite a bit larger (about 8.5 meters in diameter), even larger than the shipping container for the JWT (by about 3 meters). There's also a large shipping container specially made that handles a lot of the same problems.

To build on this and give more examples, the largest telescope is the FAST ratio telescope, with a 500m diameter. The largest fully steerable telescope is the Green Bank Telescope with 100m diameter.

But both of those are radio telescopes, so a more fair comparison with JWST would be the sizes of optical/near-infrared/mid-infrared telescopes. The Gran Telescopio Canarias has an 10.4m diameter primary that is made of a number of smaller mirrors. Keck's design is the similar (and came before the GTC), though the primary diameter is slightly smaller at 10m. The Large Binocular Telescope (LBT) has two 8.4m diameter mirrors. All three of these telescopes are capable of observing in the mid-infrared; in principle with higher angular resolution but less stable point spread functions and reduced sensitivity compared to JWST.

The Vera Rubin Observatory mirror is about the same diameter as the LBT's mirrors, but the large secondary and tertiary mirrors reduce the collecting area to be equivalent to that of a ~6.7m mirror.

Why not fly the telescope to the launch site?

The answer is in the article.

Ah, must have accidentally skipped of that part. Cheers!

For anyone else: “ While STTARS has previously transported Webb components to other NASA or partner facilities primarily by air, the team chose to transport Webb by sea to Kourou due to the logistics of landing at the Cayenne Airport in French Guiana. The 40-mile (65-kilometer) route between the airport and the launch site features seven bridges that STTARS would have been too heavy to cross. In addition, the drive from the Port de Pariacabo to Webb’s launch site is relatively short. In comparison, a drive from the Cayenne Airport to the launch site, factoring in STTARS’ slow speeds and other constraints, would have taken about two days.”

Also the package is about 1 foot too tall to fit in an AN-225.

Telescope in feet 110x18x15

Antonio AN-225 cargo 142x21x14

Edit: it would fit in a Beluga 124x23x23

It also fits in a C-5

Next question: Why does it need to be launched from another continent? Why not FL or TX?

Because they're launching on an Ariane rocket, which is a French rocket that launches from French Guiana.

As to why they chose that, I have no idea

> The rocket had a streak of 82 consecutive successful launches between 9 April 2003 and 12 December 2017.

That's why.

(We also like international cooperation. We build the telescope, ESA chips in with the launcher. Same situation with Orion and the ESA's service module.)

You get an advantage launching closer to the equator. The velocity of the Earth at the equator is higher so less deltaV is required from the rocket itself when compared to launching somewhere closer to the poles.

You get a speed boost the closer you are to the equator and if you want an equatorial orbit you have to spend fuel in orbit to correct down to zero degrees.

It is way cheaper to correct these things on the planet than with bigger rockets.

Probably a dumb question but while not seal it before shipping?

Half the article, the main picture and the first video are about sealing it into the special transport container.

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