Centauri Dreams has long championed Webster Cash’s innovative New Worlds mission concepts, which would use a ‘starshade’ to block the light of distant stars to reveal their planetary systems. Cash envisions using multiple spacecraft for this assignment, one the starshade itself, the other a telescope that would make the needed observations. After a series of ups and downs, New Worlds now receives new life in the form of a $1 million award from NASA to study the starshade’s possibilities.
Remember that we’re still at an early research level when it comes to funding of this kind — the actual observatory, a design Cash calls New Worlds Observer — would cost an estimated $3.3 billion to design and build. Other mission concepts are still in play (fully nineteen observatory concepts have been chosen for further study), so the road ahead is by no means clear as we look toward space missions that can identify Earth-like planets around other stars. But Cash’s designs are well vetted, and should prove attractive to those responsible for narrowing the field.
At right is a simulation of what New Worlds Observer might see if pointed at Sol from 10 parsecs out. The blue bulge at the top is the Earth; the second object is Venus. To do this kind of work, NWO would use a starshade fifty yards in diameter, placed at Lagrange point 2 (L2), where a stable orbit can be achieved that balances the gravitational effects of the Sun and the Earth. The projected four-meter telescope is considerably larger and more powerful than the Hubble Space Telescope. Telescope and occulter would be stationed some 50,000 kilometers from each other along the line of sight to a nearby star, with the starshade moved as needed to select a variety of targets (you can see that two starshades would make even more sense, one able to move into position on the next star while the first observes its target).
Image: A simulated image of the inner solar system taken at 10 parsecs with a 4-meter telescope. Credit: Phil Oakley.
What to do with New Worlds Observer? The detection of the light of individual planets would allow us to understand the entire exoplanetary system, while using spectroscopy to analyze atmospheres for biomarkers like methane, oxygen and water. Photometric methods could show us variations in color as surface features rotate in and out of view. Take those methods to the max and you may be able to identify oceans, continents, polar caps and cloud banks. New Worlds Observer is a powerful concept that can advance our knowledge of rocky worlds around other stars and pave the way for more expansive missions to come.
The observations done with New Worlds Observer will require a telescope; these could be done with one that will already be existing when it launches such as JWST. Ideally, however, New Worlds would use a dedicated, visible light Hubble-class telescope to be designed with the rest of the mission.
Money, money, money…
Yes, the New Worlds Observer mission as currently constituted includes the 4-meter instrument, although there had been previous talk about using a starshade in conjunction with JWST. I gather the latter isn’t likely, but we can still do terrific work with the layout NWO now offers.
With only 400 stars within 10 parsecs, is it more “cost effective” to do this starshade concept, or, for a few bucks more, (even, say, 50 billion dollars more) could we get out to 550 A.U. and then REALLY have a telescope with Sol as our lens?
I’m thinking we have virtually the whole of the universe to cherry pick at Point 550, so why not put the money into a big rocket instead of a big telescope? Get a modest telescope to Point 550, and it’ll be taking pictures of license plates on alien teens’ jalopies 10 billion light years out, er, right?
I see the saving of time and money for the starshade, (especially time) but how much of a Point 550 project could be accomplished in the same amount of time and money?
30% ???
A light sail would have to be invented, probably, but isn’t “inventing the starshade” as daunting a engineering hump to get over? Again, I’m mostly wondering about cost effectiveness.
Edg
Edg, there’s probably enough distance between the two concepts to justify building the starshade. It can be done with existing technologies, whereas reaching 550 AU is going to take a serious propulsion upgrade. As you say, a solar sail mission could be attempted, but we haven’t yet reached the point where we can launch a sail fast enough to get to 550 AU in the lifetime of a researcher (for that matter, we have yet to fully deploy and fly a sail in space). I’m a big proponent of the FOCAL mission, as you know, but I think the starshade has a place as we work toward the gravity lens mission.
Pretty sound concept and simple too.
I went to the site and tried to access info about the station keeping technology, but they didn’t have it yet. I’d like to study how they intend to achieve autonomous station keeping.
Yes, the New Worlds site is still under construction, and just got something of a re-design. I’m interested in the autonomous operations question, too; I’ll see if I can find anything out about it.
Hi Folks;
Could a star shade be used to block out radially disposed sections of supermassive blackhole accreetion disks? Being able to study such disks in such a maner might enable us to tease out novel general relativistic effects that might be resolved by studying the different emmission frequencies of different radially differential elements of the disks. Effects that could be studied are light polarization, unexpected frequency distributions, unexpected relativistic dopplar effects in terms of both special and general relativity and the list goes on.
I am not sure if such a shade could work, but it might be worth a try.
Thanks;
Jim
The problem looks indeed very similar to finding small faint terrestrial planets near a bright star. Close to the event horizon will be the most exciting physics.
But a planet finder will most likely operate in infrared. Is that a good choice here? Not to get the best resolution, I guess.
NASA’s “New Worlds Observer” Will be Able to Spot Oceans,
Continents and Clouds on Small Rocky Planets
NASA has got its checkbook out to spend $3 billion for a
new space telescope powerful enough to discover planets
like Earth and even signs of alien life. The New Worlds
Observer will be able to identify planetary features like
oceans, continents, polar caps and cloud banks and even
detect biomarkers (image) like methane, oxygen and water
if they exist.
Its “eye” to the cosmos will be a four-meter-wide mirror
that will collect nearly three times as much light as the
2.4-meter mirror on the Hubble space telescope.
The NWO will feature a 50-yard wide, daisy-shaped
plastic “sunshade” with petals made from black plastic
like that used for rubbish bags. It will block the brilliant
light from the distant stars, shielding their overpowering
glare and allowing the telescope to observe any planets
in orbit around them and zero in on Earth-like planets in
other solar systems.
The thin plastic “starshade” would allow a telescope
trailing thousands of miles behind it to image light from
distant planets skimming by the giant petals without being
swamped by light from the parent stars. Researchers
could then identify planetary features like oceans,
continents, polar caps and cloud banks and even
detect biomarkers like methane, oxygen and water
if they exist.
“We think this is a compelling concept, particularly because
it can be built today with existing technology,” said Webster
Cash director of University of Colorado-Boulder’s Center
for Astrophysics and Space Astronomy. “We will be able to
study Earth-like planets tens of trillions of miles away and
chemically analyze their atmospheres for signs of life.”
Full article here:
http://www.dailygalaxy.com/my_weblog/2008/02/nasas-new-world.html
Edg – that argument doesn’t really work. While the configuration of the starshade concept can be repositioned to point at multiple targets, you need a separate telescope per target star at 550 AU (with all the associated costs of getting it out there) . Plus you’d need a starshade anyway on account of pointing your telescope at the Sun.
The “Planetscope”
A team of NASA scientists plan to balloon into the sky in search of other planets – but before you think they’ve confused a Jules Verne book with a planning document, they aren’t planning to get all the way to alien shores there with nothing but air to hold them up. The balloons will hoist two-meter telescopes ten kilometers up where they can see space a lot clearer than their land-bound cousins.
Full article here:
http://www.dailygalaxy.com/my_weblog/2008/03/the-planetscope.html
Meteoroid and space debris impacts in grazing-incidence telescopes
Authors: J. D. Carpenter, A. Wells, A. F. Abbey, R. M. Ambrosi
(Submitted on 13 Mar 2008)
Abstract: Micrometeoroid or space debris impacts have been observed in the focal planes of the XMM-Newton and Swift-XRT X-ray observatories. These impacts have resulted in damage to, and in one case the failure of, focal-plane Charge-Coupled Device (CCD) detectors.
We present a simple model for the propagation of micrometeoroids and space debris particles into telescopes with grazing incidence X-ray optics. The risks of future focal-plane impact events in three present (Swift-XRT, XMM-Newton, and Chandra) and two future (SIMBOL-X and XEUS) X-ray observatories are then estimated.
The probabilities of at least one impact occurring in the Swift-XRT, XMM-Newton, and Chandra focal planes, in a one year period from the time of writing in November 2007 are calculated to be ~5% and ~50% and ~3%. First-order predictions of the impact rates expected for the future SIMBOL-X and XEUS X-ray observatories yield probabilities for at least one focal-plane impact, during nominal 5-year missions, of more than 94% and 99%, respectively.
Future X-ray observatories, with large collecting areas and long focal lengths, may experience much higher impact rates on their focal-plane detectors than those currently in operation. This should be considered in the design and planning of future missions.
Comments: Accepted by Astronomy & Astrophysics, February 2008
Subjects: Astrophysics (astro-ph)
Cite as: arXiv:0803.1983v1 [astro-ph]
Submission history
From: James Carpenter [view email]
[v1] Thu, 13 Mar 2008 14:57:21 GMT (627kb)
http://arxiv.org/abs/0803.1983
NASA’S WEBB TELESCOPE SUNSHIELD PRELIMINARY DESIGN REVIEW COMPLETE
GREENBELT, Md. – The tennis court-sized sunshield built by Northrop
Grumman for NASA’s James Webb Space Telescope has completed its
preliminary design review at the company’s Space Technology facility.
The Webb Telescope is the next-generation space observatory, designed to
explore phenomena from distant galaxies to nearby planets and stars.
>From the origins of the universe to the formation of star systems
capable of supporting life on planets such as Earth, the Webb telescope
will give scientists unprecedented access to unexplored regions of
space.
“The sunshield is absolutely critical to the Webb telescope mission”
says Keith Parrish, JWST Sunshield Manager at NASA’s Goddard Space
Flight Center, Greenbelt, Md. “It will be folded up around the telescope
when the telescope is aboard its rocket during launch. The sunshield
will then deploy in space to shade the sensitive, precision telescope
optics and science instruments from the Sun and enable the observatory
to reach its proper operating temperature and environment. Without it,
the telescope and instruments can’t work. Northrop Grumman is leveraging
their experience in large deployable structures in space to come up with
a design that will do the job for the Webb telescope.”
The five-layer sunshield consists of extremely thin, specially coated
reflective membranes and a supporting structure. The sunshield blocks
solar heat, keeping the telescope’s science instruments operating at
cryogenic temperatures so astronomers can study distant galaxies, young
stars and planetary systems at near- and mid-infrared wavelengths.
“The completion of the preliminary design review allows the detailed
engineering design to move forward and maintains the delivery schedule
for the Observatory,” said Martin Mohan, Program Manager for the Webb
Telescope.
Completion of the preliminary sunshield design is the latest in a series
of significant accomplishments. One year ago, the Northrop Grumman
engineers developing sunshield membrane materials demonstrated that the
sunshield prototype material had been successfully tested, functioning
as predicted, in a relevant environment (simulating space).
Northrop Grumman is prime contactor for the Webb Telescope, leading the
design and development effort under contract to NASA Goddard. It is
scheduled for launch in 2013.
For related images and more information, please visit:
http://www.nasa.gov/centers/goddard/news/topstory/2008/jwst_sunshield.html
For the James Webb Space Telescope Mission Website, visit:
http://jwst.gsfc.nasa.gov
For Northrop Grumman’s Website, visit: http://www.ngc.com
Telescope could focus light without a mirror or lens
NewScientist.com news service May 1, 2008
Observatoire Midi Pyrenees
astronomers have proposed building a
space telescope powerful enough to
see Earth-sized planets within 30
light years of Earth. The telescope
would be a Fresnel imager, focusing
light by passing it through a
pattern of holes carved in an opaque
sheet. Because it relies on a foil
sheet rather than a massive mirror,
it…
http://www.kurzweilai.net/email/newsRedirect.html?newsID=8589&m=25748
The Futures Channel presents a short film on the
Starshade:
http://www.thefutureschannel.com/dockets/realworld/the_starshade/index.php