Quote from: Star One on 04/21/2017 11:22 amQuote from: as58 on 04/21/2017 10:40 amMore photos of the mirror are available at https://wfirst.gsfc.nasa.gov/gallery-photos.html. I wonder how the price tag has gone from $2.6B- $2.8B given in last year's decadal mid-term to $3.2B. It's not quite clear if both estimates include the same things, though. Slides from last week's NAC Science Committee meeting don't seem to be available yet.Isn't it the addition of the Coronagraph pushing the price tag up?Yes, but I believe that was already included in the previous cost estimate.
Quote from: as58 on 04/21/2017 10:40 amMore photos of the mirror are available at https://wfirst.gsfc.nasa.gov/gallery-photos.html. I wonder how the price tag has gone from $2.6B- $2.8B given in last year's decadal mid-term to $3.2B. It's not quite clear if both estimates include the same things, though. Slides from last week's NAC Science Committee meeting don't seem to be available yet.Isn't it the addition of the Coronagraph pushing the price tag up?
More photos of the mirror are available at https://wfirst.gsfc.nasa.gov/gallery-photos.html. I wonder how the price tag has gone from $2.6B- $2.8B given in last year's decadal mid-term to $3.2B. It's not quite clear if both estimates include the same things, though. Slides from last week's NAC Science Committee meeting don't seem to be available yet.
Do you think they'll end up having to remove it to keep the project within a reasonable cost level?
Quote from: Star One on 04/21/2017 01:14 pmDo you think they'll end up having to remove it to keep the project within a reasonable cost level?I think that they are sending a clear message to the science and engineering teams that NASA intends to keep this mission within its cost cap.
Quote from: as58 on 04/21/2017 10:40 amMore photos of the mirror are available at https://wfirst.gsfc.nasa.gov/gallery-photos.html. I wonder how the price tag has gone from $2.6B- $2.8B given in last year's decadal mid-term to $3.2B. It's not quite clear if both estimates include the same things, though. Slides from last week's NAC Science Committee meeting don't seem to be available yet.The $2.6-2.8B in the mid-decadal assessment is in FY15 dollars, the $3.2B is measured in the year those funds are spent.
That said, I'd hate to lose the coronagraph and ability to do formation flying with an occulting mask, but I suspect at least the latter is going to be lost, if it's not already.
The Demographics of Rocky Free-Floating Planets and Their Detectability by WFIRSTPlanets are thought to form via accretion from a remnant disk of gas and solids around a newly formed star. During this process material in the disk either remains bound to the star as part of a either a planet, a smaller celestial body, or makes up part of the the interplanetary medium; falls into the star; or is ejected from the system. Herein we use dynamical models to probe the abundance and properties of ejected material during late stage planet formation and estimate their contribution to the free-floating planet population. We present 300 N-body simulations of terrestrial planet formation around a solar-type star, with and without giant planets present, using a model that accounts for collisional fragmentation. In simulations with Jupiter and Saturn analogs present, about one-third of the initial (~5 Mearth) disk mass is ejected, about half in planets more massive than Mercury but less than than 0.3 Mearth, and the remainder in smaller bodies. Most ejections occur within 25 Myr, which is shorter than the timescale typically required for Earth-mass planets to grow (30-100 Myr). When giant planets are omitted from our simulations, almost no material is ejected within 200 Myr and only about 1% of the initial disk is ejected by 2 Gyr. We show that about 2.5 terrestrial-mass planets are ejected per star in the Galaxy. We predict that the space-borne microlensing search for free-floating planets from the Wide-Field Infra-Red Space Telescope (WFIRST) will discover up to 15 Mars-mass planets, but few free-floating Earth-mass planets.
NASA’s dark-energy probe faces cost crisishttp://www.nature.com/articles/n-12339962
The committee is co-chaired by Peter Michelson, the chair of the physics department at Stanford University who has worked on high-energy astrophysics missions such as Fermi; and Orlando Figueroa, a retired NASA official whose career included serving as deputy director of the Goddard Space Flight Center and director of NASA’s Mars exploration program. The other members include a mix of scientists, engineers and program managers.“We are confident this review will provide the insight and confidence among key stakeholders necessary to move toward what promises to be an exciting science investigation bound to reshape our understanding of the universe,” Thomas Zurbuchen, NASA associate administrator for science, said in a statement announcing the membership of the review panel.
Your report on NASA's next large space telescope, the Wide-Field Infrared Survey Telescope (WFIRST), misleadingly implies that NASA's dark-energy probe faces a cost crisis (Nature 546, 195; 2017). NASA has not yet completed the work of estimating the costs of the mission and is not facing funding difficulties, let alone a crisis.At the recommendation of the US National Academies of Science, Engineering, and Medicine, NASA is convening an independent technical, management and cost review of WFIRST. The purpose is to ensure that the mission's scope and cost are correctly aligned at this early stage, so that we can proceed with assurance to realize the scientific goals without overspending.This review was recommended by the National Academies in 2014 and again in 2016, and is not motivated by the mission's current status. We are confident that the review will contribute to the successful development of a breakthrough mission that will reshape our understanding of dark energy, exoplanets and the Milky Way.
NASA has not yet completed the work of estimating the costs of the mission and is not facing funding difficulties, let alone a crisis.
NASA has turned a lot of heads in recent years thanks to its New Worlds Mission concept – aka. Starshade. Consisting of a giant flower-shaped occulter, this proposed spacecraft is intended to be deployed alongside a space telescope (most likely the James Webb Space Telescope). It will then block the glare of distant stars, creating an artificial eclipse to make it easier to detect and study planets orbiting them.The only problem is, this concept is expected to cost a pretty penny – an estimated $750 million to $3 billion at this point! Hence why Stanford Professor Simone D’Amico (with the help of exoplanet expert Bruce Macintosh) is proposing a scaled down version of the concept to demonstrate its effectiveness. Known as mDot, this occulter will do the same job, but at a fraction of the cost.
As such, D’Amico – an assistant professor and the head of the Space Rendezvous Laboratory (SRL) at Stanford – and and Bruce Macintosh (a Stanford professor of physics) teamed up to create a smaller version called the Miniaturized Distributed Occulter/Telescope (mDOT). The primary purpose of mDOT is to provide a low-cost flight demonstration of the technology, in the hopes of increasing confidence in a full-scale mission.
Consisting of two parts, the mDOT system takes advantage of recent developments in miniaturization and small satellite (smallsat) technology. The first is a 100-kg microsatellite that is equipped with a 3-meter diameter starshade. The second is a 10-kg nanosatellite that carries a telescope measuring 10 cm (3.937 in) in diameter. Both components will be deployed in high Earth orbit with a nominal separation of less than 1,000 kilometers (621 mi).With the help of colleagues from the SRL, the shape of mDOT’s starshade was reformulated to fit the constraints of a much smaller spacecraft. As Koenig explained, this scaled down and specially-designed starshade will be able to do the same job as the large-scale, flower-shaped version – and on a budget!