Review: The James Webb Space Telescope

For the 6th meeting of the Astronomy Twitter Journal Club we decided to try something a little different – just a discussion about a topic rather than a paper. This was purely because we didn’t have time to pick and review a paper; it’s not a new direction! Normal service will resume on Thursday 28th July, 2011.

The discussion topic selected by a vote was the James Webb Space Telescope.

Recently, the US Congress released its Appropriations Bill, which covers science funding and in particular, decides how much funding NASA gets. The Bill includes the following statement:

The bill terminates funding for the James Webb Space Telescope, which is billions of dollars over budget and plagued by poor management.

So, is this a good idea? Was it expected? Is it a disaster?

On to the discussion… Ialso recommend reading the full Tweet archive – I didn’t cover all the points raised as this post was getting too long.

Is cancelling going to achieve anything?

It’s important to realize that even if JWST is eating up astrophysics money, the proposed cancellation does not restore one cent. – johngizis

 #JWST has gone too far for cancellation; should complete it, & it will be good. – DrMRFrancis

would we *gain* anything by scrapping JWST? Money is lost, not redistributed – teagazer

point for me is: if cancel #jwst we won’t have anything else for less money OR sooner up there. so might as well finish! – sarahkendrew

Budget and costs – questions and points

How much over budget is it? – chris_tibbs

It’s way over budget. But the initial budget was unrealistic. – kashfarooq

The future costs depend on launch date. If there isn’t a lot of extra money soon, the overall costs skyrocket – johngizis

Does anyone know the ratio between the money required to complete JWST and the money already invested? – chris_tibbs

According to the link here, it is 1/2 or possible 1/3! – johngizis

Are there any alternatives?

Without Shuttle HST is a dead duck. #JWST is a necessary risk. We have no plan B – astrojenny

How much of #JWST science could be done with other upcoming facilities? e.g. ELT – astronomyjc

Depending how well extreme AO works, ELTs may match/exceed JWST in optical/nearIR. See this conf – janerrigby

nothing can match JWST in the mid-IR: 60-100x more sensitive than Spitzer for spectroscopy, at higher R – janerrigby

Much of the wavelength space covered by #JWST is inaccessible from the ground…. sensitivity spectacular – sarahkendrew

“We are rapidly approaching the limit of what can be done scientifically without the James Webb”

This was a quote from, and prompted the following exchange:

Erm – no we aren’t – tharries

Perhaps would be better to say we’re approaching the limit of what can be done at JWST wavelengths? – astronomyjc

Sorry, don’t agree with the wavelength argument either, we would just have to chose problems that are tractable. – tharries

i.e. ignore the science that requires wavelengths that can only be seen from space? – kashfarooq

define tractable. Manageable only if we stop pushing technology/science boundaries? Depressing thought. – vrooje

well, in the areas where Hubble has pushed the most (high-z, exoplanets), #JWST will push much further – sarahkendrew

Public Perception

Astronomers rely on the goodwill of the public. I think JWST risks damaging this, particular given the current economic climate – tharries

Then we should do better at communicating why its important rather than scrap $billions already done – teagazer

Has there been much media coverage of the proposed cancellation in the US? How aware is the public of the problems?  – astronomyjc

Our astro ambitions are ALWAYS constrained by economic realities. This is no different. – tharries

Public is very forgiving if the results are awesome. See HST again: cost overruns, faulty 1st implementation, but who remembers? – DrMRFrancis

If the images are as mind blowing as HST, everyone will forget the cost – kashfarooq

seems to me it doesn’t matter what we astronomers think: jwst hasn’t been effectively sold to American public and congress – Matt_Burleigh

However, definitely needs to be better PR on #JWST : main stories are abt. budget overruns, not what rockin’ science it will do. – DrMRFrancis

Is anyone worried about the technical ambition?


Does the technical ambition worry anyone? Sending a huge mirror to L2 that has to unfold when it gets there? – kashfarooq


worrying – yes. but if we don’t try then it definitely won’t happen. – teagazer

Yes, absolutely. Makes me very nervous after the issues HST had, but many smaller unserviceable missions have been fine – vrooje

Yes, but we have to at least attempt it to find out. – chris_tibbs

This has always been a big worry 4 me. But JWST ppl have always insisted it can b done. They cant say anything else! I’ve been repeatedly told “military have done it many times”- Matt_Burleigh

Def. worrying but they must be pretty sure it will work – astronomyjc

Be good to see how RadioAstron does with its unfurling  – astronomyjc

the design/test/verification/redundancy requirements on space hardware is staggering. so much is done to mitigate risk. – sarahkendrew

And when it comes down to it the riskiest part of the whole thing is probably the launch – astronomyjc

Ariane 5 ECA current has 100% success rate (30 launches) – tharries

Great discoveries

A great question from Sarah:

POLL: what would be the one unexpected discovery #jwst could make that would justify the spend/overrun? – sarahkendrew


Signatures of greenhouse gas emissions in the atmosphere of an exoplanet. Industrial/developing civilisation emissions. Not just life, intelligent life.- vrooje

Oxygen and Methane in an exoplanet’s atmosphere – kashfarooq

Tough call: unexpected is by def. unpredictable! 🙂 As a cosmologist, I’d love unexpected high-z discoveries. – DrMRFrancis

signature of life on a nearby exoEarth – Matt_Burleigh

Light from just 300 million years after the Big Bang… Wow. –kashfarooq

Good question, @kashfarooq : anyone know what #JWST might say about 1st stars? That would be important! – DrMRFrancis

ALIENS!! (sorry, someone had to say it!) – astronomyjc

Exoplanet discoveries will definitely make the public forgive all! – DrMRFrancis

I vote for the FACE of GOD! should appeal to Congress 🙂 – sarahkendrew

I wonder if the most impactful, unforeseen #JWST discovery might come from our local neighborhood instead of early universe – vrooje

To conclude

Obviously, we were preaching to the converted here – mostly, everyone was highly partisan, or even directly affected by the decision (sarahkendrew is working on MIRI, one of #JWST‘s instruments).

I’ll end the post with this:

How do we get media, public to think about science? – janerrigby

Write about it — all of us. Anyone who cares about this stuff is an ambassador for science. – DrMRFrancis

And here is my contribution to that point.


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