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Loren Grush and Aeolus




Space is for everybody. It's not just for a few people in science or math, or for a select group of astronauts. That's our new frontier out there, and it's everybody's business to know about space.

Christa McAuliffe

SPACE LEGEND OF THE WEEK

Gregory Bruce Jarvis (August 24, 1944 – January 28, 1986) was an American engineer who died during the destruction of the Space Shuttle Challenger on mission STS-51-L, where he was serving as Payload Specialist for Hughes Aircraft and sat next to Christa McAuliffe

He was originally scheduled for a flight the previous March but was bumped when Senator Jake Garn, Republican of Utah, was given his spot. The same thing happened on his next turn, the flight early in January when a Florida Congressman, Bill Nelson, took his place. Mr. Jarvis rejoiced when he was rescheduled for flight 51-L.

Aerospace engieer who got his degree and masters in Electrical Engineering and was manager of the f-1, f-2 and F-3 spaecraft.

During salvage operations to raise the crew deck from the ocean floor, his body escaped from the wreckage, floated to the surface, and disappeared back into the sea. On April 15, 1986, on the last scheduled attempt to recover wreckage, it was rediscovered and returned to shore. Jarvis was cremated and his ashes scattered in the Pacific Ocean.

Space Word of the week

Lithobraking is a landing technique used by unmanned space vehicles to safely reach the surface of a celestial body while reducing landing speed by impact with the body's surface.

Lithos is a Greek word meaning "rock" or "stone." like Lithosphere: The crust of a planet.


The first successful lithobraking was achieved by the Soviet Luna 9 probe resulting in the first soft landing on the Moon. Lithobraking is typically accompanied by the use of other techniques like retrorocket braking or the use of heat shields and parachutes to reduce speed prior to impact. The Mars Pathfinder and Mars Exploration Rover programs have used this approach successfully.

Lithobraking is also used as a humorous euphemism for the result of a spacecraft crashing into the surface of a body with no measures to ensure its survival, either by accident or with intent

Aeolus

launch 22 August 2018, 21:20 UTC

Atmospheric Dynamics Mission Aeolus built by Airbus in Stevenage here in the UK and the LIDAR was built in france.



  • Aeolus orbits in a Sun-synchronous, dusk/dawn orbit where the local mean solar time of passage for equatorial latitudes is around sunrise or sunset, so that the satellite rides the terminator between day and night. Riding the terminator is useful for active radar satellites, as the satellites'

  • Observations of the wind will be taken from the night-side of the satellite to avoid the solar background. While orbiting over the hemisphere experiencing winter, the satellite will enter Earth’s shadow for up to 20 minutes per orbit. This means that the satellite will be subjected to huge temperature changes as it passes from day to night. The thermal design is, therefore, robust.

  • solar panels can always see the Sun, without being shadowed by the Earth, 320 km above Earth. This is a relatively low orbit and a compromise between acquiring the measurements and keeping fuel consumption to a minimum. A lower altitude increases the amount of fuel needed to maintain a steady orbit over the life of the mission.

The ALADIN instrument (Atmospheric LAser Doppler INstrument) is a direct detection ultraviolet laser lidar consisting of three major elements: a transmitter, a combined Mie and Rayleigh backscattering receiver assembly, and a Cassegrain telescope with a 1.5 metres (4.9 ft) diameter.

The transmitter architecture is based on a 150 mJ diode-pumped frequency-tripled Nd:YAG laser operating in the ultraviolet at 355 nm.[7] The Mie receiver consists of a Fizeau spectrometer with a resolution of 100 MHz (equivalent to 18 m/s). The received backscatter signal produces a linear fringe whose position is directly linked to the wind velocity; the wind speed is determined by the fringe centroid position to better than a tenth of the resolution (1.8 m/s). The Rayleigh receiver employs a dual-filter Fabry–Pérot interferometer with a 2 GHz resolution and 5 GHz spacing. It analyzes the wings of the Rayleigh spectrum with a CCD; the etalon is split into two zones, which are imaged separately on the detector.


Anne Grete Straume mission scientist.

The processing of the backscatter signals will produce line-of-sight wind-component profiles above thick clouds or down to the surface in clear air along the satellite track, every 200 kilometres (120 mi). Wind information in thin cloud or at the tops of thick clouds is also attainable; from the data processing, information on other elements like clouds and aerosols can also be extracted. The data will be disseminated to the main NWP-centres in near-real-time.

Development of the ALADIN instrument has been problematic. The ultraviolet laser was causing damage to the optical surfaces in a vacuum. ESA scientists asked NASA for support, however NASA has minimal experience with lidar of this design. Technology required for the satellite was pushing the technology envelope, therefore after problematic development ESA asked Airbus to perform additional full-model tests in a vacuum before continuing mission development. Overall complications involved in the instrument caused an estimated 50% final cost overrun; ESA has agreed to come with additional funding for the project.

#esa #earthgroupies #nasa #Aeolus

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