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Zonal Flows and Oberth Delta V



To be the first to enter the cosmos, to engage, single-handed, in an unprecedented duel with nature-

could one dream of anything more?

Yuri Gagarin

On this Day

  • August 17 1970 – Venera program: Venera 7 launched on a Molniya 8K78M. It will later become the first spacecraft to successfully transmit data from the surface of another planet (Venus). The probe transmitted information to Earth for 53 minutes, which included 20 minutes from the surface. It was found that the temperature at the surface of Venus was 475 °C

  • 60 Years ago Augst 17th 1958 – Pioneer 0, America's first attempt at lunar orbit, is launched using the first Thor-Able rocket and fails. Notable as one of the first attempted launches beyond Earth orbit by any country.

  • 150 Years Ago August 18th - 1868 – French astronomer Pierre Janssen discovers helium.

Space Legend of the Week

Umberto Guidoni (born 18 August 1954 in Rome) is an Italian astrophysicist, science writer and a former ESA astronaut,

  • first European to visit the International Space Station.

  • He is a veteran of two NASA space shuttle missions. STS-75, STS-100

  • He was also a Member of the European Parliament (MEP) from 2004 to 2009,

  • elected within the Party of Italian Communists.

  • doctorate in astrophysics from the University of Rome La Sapienza in 1978

  • research projects was the Tethered Satellite System, which was part of the payload of the STS-46 mission

  • First flight Space Shuttle Columbia STS-75 in 1996, which included the second flight of the TSS system (TSS-1R).

  • 2001 - STS-100, first European on board ISS

  • Space Shuttle Endeavour carried the Raffaello Multi-Purpose Logistics Module for its maiden flight

  • as well as the Space Station Remote Manipulator System (SSRMS), the Canadian robotic arm used extensively to assemble the ISS

  • Guidoni was assigned to ESA's European Space Research and Technology Centre (ESTEC) as crew support for the payloads to be developed for the Columbus Laborator

  • n 2007 was the speaker of the radio program entitled “From the Sputnik to the Shuttle”

  • in 2011, was published the book “From the Earth to the Moon”

  • He published articles and books including books for children such as "Martino on Mars"

Space Word of the week

Delta V: Difference or change in velocity.

∆v as used in spacecraft flight dynamics, is a measure of the impulse that is needed to perform a maneuver such as launch from, or landing on a planet or moon, or in-space orbital maneuver. It is a scalar (magnitude and direction) that has the units of speed. As used in this context, it is not the same as the physical change in velocity of the vehicle.

  • Delta-v is the change in velocity that can be achieved by burning that rocket's entire fuel load.

  • is proportional to the thrust per unit mass and the burn time. It is used to determine the mass of propellantrequired for the given maneuver through the Tsiolkovsky rocket equation

  • For multiple maneuvers, delta-v sums linearly..

  • For interplanetary missions delta-v is often plotted on a porkchop plot, which displays the required mission delta-v as a function of launch date.

  • For the Voyager program, engineers at JPL plotted around 10,000 potential trajectories using porkchop plots, from which they selected around 100 that were optimal for the mission objectives. The plots allowed them to reduce or eliminate planetary encounters taking place over the Thanksgiving or Christmas holidays, and to plan the completion of the mission's primary goals before the end of the fiscal year 1981

  • When designing a trajectory, delta-v budget is used as a good indicator of how much propellant will be required.

Space Fact

In astronautics, a powered flyby, or Oberth maneuver, is a maneuver in which a spacecraft falls into a gravitational well, and then accelerates when its fall reaches maximum speed. The resulting maneuver is a more efficient way to gain kinetic energy than applying the same impulse outside of a gravitational well. The gain in efficiency is explained by the Oberth effect, wherein the use of an engine at higher speeds generates greater mechanical energy than use at lower speeds. In practical terms, this means that the most energy-efficient method for a spacecraft to burn its engine is at the lowest possible orbital periapsis, when its orbital velocity (and so, its kinetic energy) is greatest


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