Tag: WFIRST

Great Nations Need Great Observatories

This new image from NASA’s Hubble Space Telescope, shows the tentacled Southern Crab Nebula. The nebula, officially known as Hen 2-104, appears to have two nested hourglass-shaped structures that were sculpted by a whirling pair of stars in a binary system. The duo consists of an aging red giant star and a burned-out star, a white dwarf. The red giant is shedding its outer layers and some of this ejected material is attracted by the gravity of the companion white dwarf. The result is that both stars are embedded in a flat disk of gas stretching between them. This belt of material constricts the outflow of gas so that it only speeds away above and below the disk. The result is an hourglass-shaped nebula. The bubbles of gas and dust appear brightest at the edges, giving the illusion of crab leg structures. These “legs” are likely to be the places where the outflow slams into surrounding interstellar gas and dust, or possibly material which was earlier lost by the red giant star.  (NASA and ESA)

The Hubble Space Telescope, arguably the jewel in the crown of NASA’s science missions, was launched 29 years ago.  It has been providing scientists and the public with a steady stream of previously unimagined insights about the cosmos — plus those jaw-dropping, very high-resolution images like the one above — pretty much ever since.

It has also provided the best example to date of what humans can do in space with its five repair and upgrade missions.  It did indeed launch to great skepticism, especially after a near fatal flaw was found in its key mirror.  It was also considered over budget at launch, way behind schedule and questionable scientifically and had to be fixed in orbit 353 miles into space.

The Hubble Space Telescope after its second repair and upgrade mission in 1998. (NASA)

But almost three decades into its mission now — and with decades more service likely — it clearly shows what an exceedingly ambitious project can deliver and the level of excellence that NASA, its European Space Agency partner and space scientists and engineers can achieve.  Talk about soft power.

This is important to remember as the agency’s 40-year-old Great Observatories program –that the Hubble Telescope is a part of –is under considerable threat.

The mission that was supposed to fly in the 2010s, the James Webb Space Telescope, is also way over budget, way behind schedule, and now described as a financial threat to other NASA missions. … Read more

A Reprieve for Space Science?

View of WFIRST focusing on supernova SN1995E in NGC 2441. The high-priority but embattled space telescope would, if congressional support continues, add greatly to knowledge about dark energy and dark matter, supernovae, and exoplanets.  (NASA)

 

A quick update on a recent column about whether our “golden age” of space science and discovery was in peril because of cost overruns and Trump administration budget priorities that emphasized human space travel over science.

The 2018 omnibus spending bill that was passed Wednesday night by the House of Representatives and Thursday night by the Senate represents a major push back against the administration’s earlier NASA budget proposals.  Not only would the agency receive $1.6 billion more funding than proposed by the administration, but numerous projects that had been specifically eliminated in that proposal are back among the living.

They include four Earth science satellites, a lander to accompany the Europa Clipper mission to that potentially habitable moon and, perhaps most important, the Wide Field Infrared Survey Telescope (WFIRST) space telescope.

Funding for that mission, which was the top priority of the space science community and the National Academy of Sciences for the 2020s, was eliminated in the proposed 2019 Trump budget, but WFIRST received $150 million in the just-passed omnibus bill.

A report accompanying the omnibus bill is silent about the proposed cancellation and instructs NASA to provide to Congress in 60 days a cost estimate for the full life cycle of the mission, including any additions that might be needed.  So there appears to be a strong congressional desire to see WFIRST launch and operate.

Still hanging fire is the fate of the James Webb Space Telescope, which has fallen behind schedule again and is in danger of crossing the $8 billion cap put into place by Congress in 2011.  NASA officials said this week that they will soon announce their determination about whether a breach of the program’s cost cap will occur as a result of further delays.

NASA has a fleet of 18 Earth science missions in space, supported by aircraft, ships and ground observations. Together they have revolutionized understanding of the planet’s atmosphere, the oceans, the climate and weather. The Obama administration emphasized Earth studies, but the Trump administration has sought to eliminate future Earth missions. This visualization shows the NASA fleet in 2017, from low Earth orbit all the way out to the DSCOVR satellite taking in the million-mile view.

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How Will We Know What Exoplanets Look Like, and When?

An earlier version of this article was accidently published last week before it was completed.  This is the finished version, with information from this week’s AAS annual conference.

This image of a pair of interacting galaxies called Arp 273 was released to celebrate the 21st anniversary of the launch of the NASA/ESA Hubble Space Telescope. The distorted shape of the larger of the two galaxies shows signs of tidal interactions with the smaller of the two. It is thought that the smaller galaxy has actually passed through the larger one.

This image of a pair of interacting galaxies called Arp 273 was released to celebrate the 21st anniversary of the launch of the NASA/ESA Hubble Space Telescope. The distorted shape of the larger of the two galaxies shows signs of tidal interactions with the smaller of the two. It is thought that the smaller galaxy has actually passed through the larger one.

Let’s face it:  the field of exoplanets has a significant deficit when it comes to producing drop-dead beautiful pictures.

We all know why.  Exoplanets are just too small to directly image, other than as a miniscule fraction of a pixel, or perhaps some day as a full pixel.  That leaves it up to artists, modelers and the travel poster-makers of the Jet Propulsion Lab to help the public to visualize what exoplanets might be like.  Given the dramatic successes of the Hubble Space Telescope in imaging distant galaxies, and of telescopes like those on the Cassini mission to Saturn and the Mars Reconnaissance Orbiter, this is no small competitive disadvantage.  And this explains why the first picture of this column has nothing to do with exoplanets (though billions of them are no doubt hidden in the image somewhere.)

The problem is all too apparent in these two images of Pluto — one taken by the Hubble and the other by New Horizons telescope as the satellite zipped by.

 

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Pluto image taken by Hubble Space Telescope (above) and close up taken by New Horizons in 2015. (NASA)

Pluto image taken by Hubble Space Telescope (above) and close up taken by New Horizons in 2015. (NASA)

 

Pluto is about 4.7 billion miles away.  The nearest star, and as a result the nearest possible planet, is 25 trillion miles  away.  Putting aside for a minute the very difficult problem of blocking out the overwhelming luminosity of a star being cross by the orbiting planet you want to image,  you still have an enormous challenge in terms of resolving an image from that far away.

While current detection methods have been successful in confirming more than 2,000 exoplanets in the past 20 years (with another 2,000-plus candidates awaiting confirmation or rejection),  they have been extremely limited in terms of actually producing images of those planetary fireflies in very distant headlights.  And absent direct images — or more precisely, light from those planets — the amount of information gleaned about the chemical makeup of their atmospheres  as been limited, too.… Read more

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