WHAT’S AFTER HUBBLE

January 30, 2016


HUBBLE:

It is very difficult to believe that the Hubble Telescope is twenty-five (25) years in orbit. The launch date for Hubble was April 24, 1990 and remains in operation. Hubble’s orbit outside the distortion of Earth’s atmosphere allows it to take extremely high-resolution images with negligible background light.  It rotates approximately 345 miles above our Earth.   It has recorded some of the most detailed visible-light images ever, allowing a deep view into space and time. Many Hubble observations have led to breakthroughs in astrophysics, such as accurately determining the rate of expansion of the universe. A digital photograph of the Hubble Telescope is given as follows:

HUBBLE

Every 97 minutes, Hubble completes a spin around Earth, moving at the speed of about five miles per second (8 km per second) — fast enough to travel across the United States in about 10 minutes. As it travels, Hubble’s mirror captures light and directs it into its several scientific instruments.

Hubble is a type of telescope known as a Cassegrain reflector. Light hits the telescope’s main mirror, or primary mirror. It bounces off the primary mirror and encounters a secondary mirror. The secondary mirror focuses the light through a hole in the center of the primary mirror that leads to the telescope’s science instruments.

People often mistakenly believe that a telescope’s power lies in its ability to magnify objects. Telescopes actually work by collecting more light than the human eye can capture on its own. The larger a telescope’s mirror, the more light it can collect, and the better its vision. Hubble’s primary mirror is 94.5 inches (2.4 m) in diameter. This mirror is small compared with those of current ground-based telescopes, which can be 400 inches (1,000 cm) and up, but Hubble’s location beyond the atmosphere gives it remarkable clarity.

As you might suspect, the marvelous Hubble Telescope is using technology that is considered outdated relative to what is available today.  Still working and still providing remarkable photographs and data, the scientists and engineers at NASA recognized a newer device would ultimately be needed to push the boundaries of astronomy. Hence the James Webb Telescope.  OK, just who is James Webb?

JAMES WEBB:

The man whose name NASA has chosen to bestow upon the successor to the Hubble Space Telescope is most commonly linked to the Apollo moon program, not to science.

Yet, many believe that James E. Webb, who ran the fledgling space agency from February 1961 to October 1968, did more for science than perhaps any other government official, and that it is only fitting that the Next Generation Space Telescope would be named after him.

Webb’s record of support for space science would support those views. Although President John Kennedy had committed the nation to landing a man on the moon before the end of the decade, Webb believed that the space program was more than a political race. He believed that NASA had to strike a balance between human space flight and science because such a combination would serve as a catalyst for strengthening the nation’s universities and aerospace industry.

By the time Webb retired just a few months before the first moon landing in July 1969, NASA had launched more than 75 space science missions to study the stars and galaxies, our own Sun and the as-yet-unknown environment of space above the Earth’s atmosphere. Missions such as the Orbiting Solar Observatory and the Explorer series of astronomical satellites built the foundation for the most successful period of astronomical discovery in history, which continues today.  It is absolutely fitting that the next generation telescope be named after Mr. Webb.

JAMES WEBB VS HUBBLE:

The graphic below shows an excellent comparison between Hubble and James Webb relative capabilities.

Hubble vs James Webb

JAMES WEBB TELESCOPE:

JWST is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate JWST after launch.

Several innovative technologies have been developed for JWST. These include a primary mirror made of 18 separate segments that unfold and adjust to shape after launch. The mirrors are made of ultra-lightweight beryllium. JWST’s biggest feature is a tennis court-sized five-layer sunshield that attenuates heat from the Sun more than a million times. The telescope’s four instruments – cameras and spectrometers – have detectors that are able to record extremely faint signals. One instrument (NIRSpec) has programmable micro-shutters, which enable observation up to 100 objects simultaneously. JWST also has a cryo-cooler for cooling the mid-infrared detectors of another instrument (MIRI) to a very cold 7 K so they can work.  The JPEG below will show the instrumentation assembled into the platform and give a very brief summary of purpose.

JAMES WEBB SPECIFICS

The telescope will be “parked” 932,000 miles above Earth into space; obviously, beyond our moon.  With the ability to collect much more light than Hubble, the Webb Telescope will be able to see distant objects as they existed much earlier in time, specifically 13.5 billion years earlier.  This number is only 200,000 years after the “big bang”.

Other JPEGs of the telescope are given as follows:

James Webb in Orbit

(ABOVE) The Webb Telescope in Orbit.

Given below:  The James Webb Telescope Team.

TEAM

On 6 July 2011, the United States House of Representatives’ appropriations committee on Commerce, Justice, and Science moved to cancel the James Webb project by proposing an FY2012 budget that removed $1.9bn from NASA’s overall budget, of which roughly one quarter was for JWST.  This budget proposal was approved by subcommittee vote the following day; however, in November 2011, Congress reversed plans to cancel the JWST and instead capped additional funding to complete the project at $8 billion.

The committee charged that the project was “billions of dollars over budget and plagued by poor management”. The telescope was originally estimated to cost $1.6bn but the cost estimate grew throughout the early development reaching about $5bn by the time the mission was formally confirmed for construction start in 2008. In summer 2010, the mission passed its Critical Design Review with excellent grades on all technical matters, but schedule and cost slips at that time prompted US Senator Barbara Mikulski to call for an independent review of the project. The Independent Comprehensive Review Panel (ICRP) chaired by J. Casani (JPL) found that the earliest launch date was in late 2015 at an extra cost of $1.5bn (for a total of $6.5bn). They also pointed out that this would have required extra funding in FY2011 and FY2012 and that any later launch date would lead to a higher total cost. Because the runaway budget diverted funding from other research, the science journal Nature described the James Webb as “the telescope that ate astronomy”. However, termination of the project as proposed by the House appropriation committee would not have provided funding to other missions, as the JWST line would have been terminated with the funding leaving astrophysics (and the NASA budget) entirely. You can see from the following digital, Congress was certainly within their right to cancel the program.

ESTIMATED COSTS

It is not an inexpensive program.  The House of Representatives, as mentioned above, did not kill the program. Launch is still scheduled for 20 October, 2018. I personally believe this was the proper move for them to make.

As always, I welcome your comments.

 

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