New Worlds is an exciting new mission proposed by Dr. Webster Cash geared at discovering terrestrial extrasolar planets. The mission includes a free-flying occulter, or starshade, that accompanies a space telescope around its L2 orbit. The telescope and occulter have a difference of about 18,000 kilometers between them. The occulter creates a deep shadow, where the telescope will sit, able to view faint planets that are otherwise lost in their parent star’s glare.
Extrasolar planets (also called exoplanets) are planets that orbit stars other than our Sun.
Current extra-solar planet detection methods rely on indirect means to infer the presence of planets. Except in very rare and exceptional cases, we do not actually see the planets there. The star is so bright that its light completely overwhelms the light from any planets. Instead, scientists measure the effects of the planets on their stars, the most widely used method being the Doppler shift method. Additionally, though we are now beginning to discover smaller, Earth-sized planets like Gliese 581c, current detection methods are heavily biased toward finding large Jupiter-class planets simply because they have the greatest effects on their stars. New Worlds Observer will allow us to detect Earth-sized planets easily and will allow us to take photographs of entire solar systems. Additionally, we will be able to determine the composition of extrasolar planet atmospheres using spectroscopy, perhaps determine whether they have continents and oceans, and possibly even whether they have life.
So far, though we are discovering new extrasolar planets all the time (over 200 are now known), we know little about other solar systems and even about the exoplanets themselves. Virtually all of the planets we have so far discovered were detected indirectly by their effects on their parent stars. New Worlds Observer will allow us to take direct snapshots of entire exosolar planetary systems. We will be able to compare other solar systems to our own to gain a better understanding of how our own solar system formed and evolved and perhaps even find evidence for life.
Yes! Recent advances have been made in starshade design and deployment, and in autonomous deep-space station-keeping. Analyses and lab demonstrations have validated these approaches.
A starshade is an occulter that will fly in front of the telescope and block the incoming starlight from the parent star, leaving the light from any planets visible. Think about trying to catch a ball and using your hand to block out the Sun so you can see it. The same basic principle applies here. For more information on what a starshade is, click here.
Spectroscopy studies the interaction between light and matter by analyzing the light various substances produce and absorb. Different substances produce different characteristic spectra that are like their fingerprints. By doing spectroscopy, we can learn what extra-solar planetary atmospheres are made of and much more.
New Worlds Observer will do spectroscopy on the light from extrasolar planets to determine what their atmospheres are made of. The composition of Earth's atmosphere is affected by life, and we believe atmospheres with life elsewhere will likewise be affected. There are certain gases like free molecular oxygen that are, as far as we know, only present in abundance in an atmosphere because of the presence of life. By searching for these gases, we may be able to determine whether a planet is inhabited.
In theory, New Worlds should be able to detect any kind of life that leaves a recognizable signature in its planet's atmosphere. It is probable that simple life (think bacteria...or simpler) is a lot more common than complex life (plants and animals), so anything we detect will probably be single-celled. There is, however, no way of knowing this for certain at this point.
Mission plans call for New Worlds Observer to be placed at a point in space called Lagrange Point 2, frequently abbreviated as L2. At L2, the gravitational effects of the sun and the Earth balance out so that an orbit here is stable. Placed at L2, New Worlds Observer would orbit 1.5 million kilometers from the Earth – this is about 4 times farther away than the Moon! L2 always lies on the side of the Earth away from the Sun, so it is an ideal place to put observatories in space since L2 always maintains the same orientation relative to the Earth and the Sun. The James Webb Space Telescope, for example, will be placed at L2.
Ideally, New Worlds Observer will use a 4-meter diameter Hubble-class visible light telescope, which will of course open new doors to the rest of the astrophysical community. A telescope this good would be able to do much more than just extrasolar planet research.
New Worlds Observer will require a telescope, but it will not use Hubble. Instead, mission plans call for a 4-meter diameter Hubble-class telescope that will work in tandem with the starshade.
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.
The thrust and fuel consumption needed to counter static and dynamic gravitational forces are much smaller than the thrust and fuel used for maneuvering to the next target. The maneuvers are so powerful that L2 becomes almost equivalent to flat space operation.
Yes. We calculate completion of the baseline 3-year mission with at least 30% propellant reserve.
The shade must be sufficiently large to fit the telescope mirror entirely within its diffracted-light shadow.
The starshade will be tilted so that the telescope sees the dark side – it will see only the very thin leading edge of the starshade illuminated by the Sun.
The two key technologies are starshade deployment and alignment control. Both have significant heritage already from other programs. Subscale demonstrations will verify these technologies. The starshade will be fully deployed three times in ground tests and carefully measured to show repeatability of accuracy. Alignment sensing will be tested in vacuum on simulated targets. Control of scattering can be measured before launch.
Manufacturing tolerances are readily accomplished with standard precision machining techniques, an area in which our team is highly experienced. We will use a number of techniques (photogammetry, laser metrology, etc.) to verify manufacturing accuracy.
