What’s Coming After Hubble and James Webb? The High-Definition Space Telescope

Decades after its momentous launch, the ever popular Hubble Space Telescope merrily continues its trajectory in low-earth orbit, and it still enables cutting-edge science. Astronomers utilized Hubble and its instruments over the years to obtain iconic images of the Crab Nebula, the Sombrero Galaxy, the Ultra Deep Field, and many others that captured the public imagination. Eventually its mission will end, and people need to plan for the next telescope and the next next telescope. But what kinds of space exploration do scientists want to engage in 20 years from now? What technologies will they need to make it happen?

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Why is that James Webb taking so fricken long? It was supposed to be up like five years ago.

dv said:

Why is that James Webb taking so fricken long? It was supposed to be up like five years ago.

budget cuts I heard

CrazyNeutrino said:

dv said:

Why is that James Webb taking so fricken long? It was supposed to be up like five years ago.

budget cuts I heard

According to wiki:

“The JWST has a history of major cost overruns and delays. The first realistic budget estimates were that the observatory would cost $1.6 billion and launch in 2011. NASA has now scheduled the telescope for a 2018 launch. In 2011, the United States House of Representatives voted to terminate funding, after about $3 billion had been spent and 75 percent of its hardware was in production. Funding was restored in compromise legislation with the US Senate, and spending on the program was capped at $8 billion. As of December 2014, the telescope remained on schedule and within budget, but at risk of further delays.”

Not so good. There has always been a concern that Hubble would die before the JWST went up. Luckily, the last Hubble servicing mission from 2009 was a complete success, so the 2011 launch date for JWST became less important.

CrazyNeutrino said:

What’s Coming After Hubble and James Webb? The High-Definition Space Telescope

Decades after its momentous launch, the ever popular Hubble Space Telescope merrily continues its trajectory in low-earth orbit, and it still enables cutting-edge science. Astronomers utilized Hubble and its instruments over the years to obtain iconic images of the Crab Nebula, the Sombrero Galaxy, the Ultra Deep Field, and many others that captured the public imagination. Eventually its mission will end, and people need to plan for the next telescope and the next next telescope. But what kinds of space exploration do scientists want to engage in 20 years from now? What technologies will they need to make it happen?

more…

From hdst_report_final_072715.pdf

Note: this report is definitely designed to be read by people with no knowledge of astronomy. If nothing else, you can browse it for the pictures.

What sort of optical telescope can accomplish the scientific goals described in previous chapters? The first consideration is aperture size. The need to discover exoplanets and to dissect galaxies at 100 pc resolution sets the size.
Hubble 2.4m, JWST 6.5m, HDST 11.7m.
This can be rolled up to fit within an existing Delta launch rocket shroud. Starshades vs. Coronagraphs – a coronagraph is preferred, but requires extraordinarily stable wavefront and line-of-sight pointing stability to maintain high contrast over long periods of time—a challenge for the telescope designers.

Detector technologies: In the UV and visible, 5 micron pixels are required to properly sample a point source imaged by the telescope, critical for crowded-field photometry, precision astrometry and time-series measurements. Given the size of the focal plane, this implies a pixel count of > 1 Gigapixel (32k on a side) for imaging sensor arrays that cover the desired ~6 arcminute field of view. In the near-IR, acceptable pixel sizes will be 10 microns with correspondingly lower pixel counts.