Musk floated an idea for upper stage recovery in a series of tweets recently, saying his company would bring Falcon 9's upper stage «back from
orbital velocity using a giant party balloon.»
He started the series of tweets with the acknowledgment that «This is gonna sound crazy,» and then said, «SpaceX will try to bring rocket upper stage back from
orbital velocity using a giant party balloon.»
Not exact matches
Fritz Zwicky
used it for the first time to declare the observed phenomena consistent with dark matter observations as the rotational speeds of galaxies and
orbital velocities of galaxies in clusters, gravitational lensing of background objects by galaxy clusters such as the Bullet cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies.
In July 2008, astronomers (Michael Endl and Martin Kürster) analyzed
used seven years of differential radial
velocity measurements for Proxima Centauri to submit a paper indicating that large planets are unlikely to be orbiting Sol's closest stellar neighbor within its habitable zone — around 0.022 to 0.054 AU with a corresponding
orbital period of 3.6 to 13.8 days.
A subsequent analysis
using the most recent kinematic and radial
velocity data available in the literature, however, found Proxima «is quitely likely» to be bound to to Stars A and B based on calculations of the binding energy of Proxima relative to the center of mass of the entire triple system, where its
orbital semi-major axis exceeds 10,000 AUs and is «on order the same size as Alpha Centauri AB's Hill radius in the galactic potential» (Wertheimer and Laughlin, 2006).
However, later observations by other astronomers
using interferometric astrometry and recent radial
velocity data found no evidence to support the existence of a companion greater than 0.8 Jupiter mass with an
orbital period around Proxima Centauri of between one and about 2.7 years (Benedict et al, 1999).
We also
used radial
velocity measurements of the host star, spanning a time range of $ \ sim $ 30 yr, to constrain the companion's mass and
orbital properties, as well as to probe the host star's spectral age indicators and general spectral energy distribution.
Using multi-epoch optical and near - IR follow - up spectroscopy with FLAMES on the Very Large Telescope and ISIS on the William Herschel Telescope we obtain a full
orbital solution and derive the fundamental parameters of both stars by modelling the light curve and radial
velocity data.