This month's AE presenter: James Aubuchon
Date of presentation: May 2019 (exact date uncertain)
Subject: How to Build a Space System II, the Space Environment Proper
Description: Space is by its nature a difficult environment in which to place and operate any kind of system. The space environment is characterized by high vacuum, temperature extremes, thermal cycling, and low gravity.
Though a small speck can damage a satellite, over 500,000 pieces of orbital debris larger than 10 cm are currently tracked by NASA. There are over 40 known meteor showers that pass through Earth’s upper atmosphere. There are also cosmic rays, micrometeoroids, and other particulates. The chemical environment includes very reactive atomic oxygen and the Van Allen radiation belts. There is an induced environment as the result of venting and outgassing from the space system itself which can interact with the space system.
Space weather variations, due mainly to the Sun, make the environment more challenging. While visible light is approximately constant, X-ray and ultraviolet light are highly variable in time and space.
Solar wind, solar flares, coronal mass ejections, solar energetic particles, x-ray flares, solar radio bursts, & solar proton events are unpredictable and are sometimes huge to monumental. These can react directly with the space system or with the Earth’s magnetosphere to cause geomagnetic storms. They can energize the ionosphere and the Van Allen radiation belts.
Direct effects on the space system may include radiation damage which can cause single event upset, latchup, loss of orientation, execution of phantom commands, and degradation of solar panels. They may result in spacecraft charging with subsequent spark discharge and possible damage. Effects on the atmosphere may result in scintillation of satellite to ground communication.
These are some of the factors which make space a difficult environment. Taken individually, any one might prove hazardous to endurance, navigation, or general operation of a space system. Taken collectively, they make operating any such system in space a massive and yet delicate undertaking.
31 May 2019
15 April 2019
Presentation: April 2019
This month's AE presenter: Jeff
Date of presentation: 15-Apr-2019
Subject: Crew Dragon
Description: In this month's scintillating presentation, Jeff talked about the project called "Crew Dragon", a NASA-funded project being designed by SpaceX. Crew Dragon is one of two variants of the larger project "Dragon 2", which itself is the successor to the earlier Dragon series of cargo transports by SpaceX. The Crew Dragon variant is designed to carry up to seven astronauts, while the Cargo Dragon variant is exclusively for cargo. A trial run successfully docked with the International Space Station on 8-Mar-2019.
Date of presentation: 15-Apr-2019
Subject: Crew Dragon
Description: In this month's scintillating presentation, Jeff talked about the project called "Crew Dragon", a NASA-funded project being designed by SpaceX. Crew Dragon is one of two variants of the larger project "Dragon 2", which itself is the successor to the earlier Dragon series of cargo transports by SpaceX. The Crew Dragon variant is designed to carry up to seven astronauts, while the Cargo Dragon variant is exclusively for cargo. A trial run successfully docked with the International Space Station on 8-Mar-2019.
25 March 2019
Presentation: March 2019
This month's AE presenter: James Aubuchon
Date of presentation: 25-Mar-2019
Subject: How to Build a Space System I, Dealing with the Earth’s Atmosphere
Description: A space system must ascend (and possibly descend) through the atmosphere. We must communicate with that system through the atmosphere. Some very small portion of the atmosphere remains even at the altitude of man-made satellites. The atmosphere has layers determined not by arbitrary boundaries, but by physical characteristics. Still, there is more than one layering system.
The best known (Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere) is determined by temperature gradient (not temperature). For example, temperature decreases with altitude in the troposphere and increases with altitude in the stratosphere.
The atmosphere is also layered by chemical composition. The atmosphere can be divided into the lower homosphere in which the atmosphere is well stirred and the higher heterosphere where chemical layering is more pronounced. There is also an ozone layer, and an ionosphere (which, itself, has layers).
There is a lower acoustic zone and a higher anacoustic zone in which sound will not propagate. These classifications schemes overlap one another.
The physical characteristics of the various layers were discussed. The exosphere blends smoothly into outer space where the gravity of the Earth is no longer strong enough to prevent the solar radiation from removing particles from the Earth’s atmosphere.
Date of presentation: 25-Mar-2019
Subject: How to Build a Space System I, Dealing with the Earth’s Atmosphere
Description: A space system must ascend (and possibly descend) through the atmosphere. We must communicate with that system through the atmosphere. Some very small portion of the atmosphere remains even at the altitude of man-made satellites. The atmosphere has layers determined not by arbitrary boundaries, but by physical characteristics. Still, there is more than one layering system.
The best known (Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere) is determined by temperature gradient (not temperature). For example, temperature decreases with altitude in the troposphere and increases with altitude in the stratosphere.
The atmosphere is also layered by chemical composition. The atmosphere can be divided into the lower homosphere in which the atmosphere is well stirred and the higher heterosphere where chemical layering is more pronounced. There is also an ozone layer, and an ionosphere (which, itself, has layers).
There is a lower acoustic zone and a higher anacoustic zone in which sound will not propagate. These classifications schemes overlap one another.
The physical characteristics of the various layers were discussed. The exosphere blends smoothly into outer space where the gravity of the Earth is no longer strong enough to prevent the solar radiation from removing particles from the Earth’s atmosphere.
18 February 2019
Presentation: February 2019
This month's AE presenter: Jeff
Date of presentation: TBD, sometime in February
Subject: TBD, but I bet it was good
Description: Yay! A presentation was delivered in February, I promise! However, due to a senior moment, I can't remember anything about it at this time. Will fill in the rest when I do remember.
Date of presentation: TBD, sometime in February
Subject: TBD, but I bet it was good
Description: Yay! A presentation was delivered in February, I promise! However, due to a senior moment, I can't remember anything about it at this time. Will fill in the rest when I do remember.
31 January 2019
No presentation: January 2019
Well, I guess I can't reuse last month's excuse, can I? Especially since it was specific to December!
Actually, I had a presentation "in the can" and ready to go for much of the month, but the calendar was full and I had no opportunity to deliver it in January. I did eventually deliver this presentation in February instead.
Now, if only I could remember what it was about...
Actually, I had a presentation "in the can" and ready to go for much of the month, but the calendar was full and I had no opportunity to deliver it in January. I did eventually deliver this presentation in February instead.
Now, if only I could remember what it was about...
31 December 2018
No presentation: December 2018
If there's one month that often gets singled out with no presentation delivered, it might (or might not) be December. Due to the holidays and other familial arrangements, there are usually fewer meetings in December, and those are often packed with other activities that are significantly higher priority than AE. That was the case in December 2018, and there was no presentation delivered that month. Sorry.
That's my story and I'm sticking to it.
That's my story and I'm sticking to it.
19 November 2018
Presentation: November 2018
This month's AE presenter: David
Date of presentation: 19-Nov-2018
Subject: Cruise Missiles
Description: David presented a brief history of cruise missiles. Cruise missiles have had a major impact on our world today as they have often been the first weapon used in modern conflicts. A cruise missile is a unmanned aircraft, similar to a drone, except that it is typically meant to hit its target and not return (with some exceptions). Cruise missiles differ from ballistic missiles, which have a boost phase and fall back to the target by gravity.
Cruise missiles were first conceptualized in WWI with the modification of Navy Curtis N-9 biplanes to fly into ships. The Army also developed the Kettering Bug, another pilotless biplane, to attack land targets. These weapons were too late for WWI, but the V1 Buzz Bomb was used extensively in WWII and widely regarded as the first effective cruise missile. Ground and Air launched cruise missiles culminated with the BGM-109 Tomahawk and AGM-86 ALCM missiles used today.
Date of presentation: 19-Nov-2018
Subject: Cruise Missiles
Description: David presented a brief history of cruise missiles. Cruise missiles have had a major impact on our world today as they have often been the first weapon used in modern conflicts. A cruise missile is a unmanned aircraft, similar to a drone, except that it is typically meant to hit its target and not return (with some exceptions). Cruise missiles differ from ballistic missiles, which have a boost phase and fall back to the target by gravity.
Cruise missiles were first conceptualized in WWI with the modification of Navy Curtis N-9 biplanes to fly into ships. The Army also developed the Kettering Bug, another pilotless biplane, to attack land targets. These weapons were too late for WWI, but the V1 Buzz Bomb was used extensively in WWII and widely regarded as the first effective cruise missile. Ground and Air launched cruise missiles culminated with the BGM-109 Tomahawk and AGM-86 ALCM missiles used today.
31 October 2018
No presentation: October 2018
Once again, events have conspired to deprive our audience of our monthly words of wisdom (if not wit) for the month of October 2018.
17 September 2018
Presentation: September 2018
This month's AE presenter: James Aubuchon
Date of presentation: 17-Sept-2018 (not 100% certain of exact date)
Subject: The source of subsonic lift
Description: Guest presenter James "Jim" Aubuchon delivered the September 2018 presentation on aerodynamics, explaining how the source of subsonic lift is Van der Waals Forces, and not the Bernoulli Effect as commonly believed.
The Bernoulli Effect is a valid observation made on liquids and published in 1738. In some circumstances, it applies to gases. However, it is an observed effect and not a fundamental cause. Similarly, Newton’s Laws are statements of observed behavior and are not fundamental causes. The fundamental forces of flight are gravity, which must be overcome, and the electromagnetic force, which provides lift. In subsonic flight, the electromagnetic force is applied to the aircraft via Van der Waals forces. The popular explanation of lift in terms of different airflow transit times above and below the wing is wrong.
The most intuitive way to visualize lift is in terms of Newton’s Laws. The wing directs airflow downward behind the wing, hence the air exerts an upward force on the wing. For a Cessna 182, air within about 5 meters above the wing is directed downward. Downwash and Van der Waals forces cause lift, not Newton’s Laws or the Bernoulli Effect. The Bernoulli Effect is useful in aircraft design to calculate the pressure distribution on aircraft surfaces, but, again, is not the proximal cause of lift.
Date of presentation: 17-Sept-2018 (not 100% certain of exact date)
Subject: The source of subsonic lift
Description: Guest presenter James "Jim" Aubuchon delivered the September 2018 presentation on aerodynamics, explaining how the source of subsonic lift is Van der Waals Forces, and not the Bernoulli Effect as commonly believed.
The Bernoulli Effect is a valid observation made on liquids and published in 1738. In some circumstances, it applies to gases. However, it is an observed effect and not a fundamental cause. Similarly, Newton’s Laws are statements of observed behavior and are not fundamental causes. The fundamental forces of flight are gravity, which must be overcome, and the electromagnetic force, which provides lift. In subsonic flight, the electromagnetic force is applied to the aircraft via Van der Waals forces. The popular explanation of lift in terms of different airflow transit times above and below the wing is wrong.
The most intuitive way to visualize lift is in terms of Newton’s Laws. The wing directs airflow downward behind the wing, hence the air exerts an upward force on the wing. For a Cessna 182, air within about 5 meters above the wing is directed downward. Downwash and Van der Waals forces cause lift, not Newton’s Laws or the Bernoulli Effect. The Bernoulli Effect is useful in aircraft design to calculate the pressure distribution on aircraft surfaces, but, again, is not the proximal cause of lift.
06 August 2018
Presentation: August 2018
This month's AE presenter: Jeff
Date of presentation: 6 Aug 2018
Subject: The TESS Mission
Description: Jeff gave a brief presentation outlining the goals and progress of NASA's Transiting Exoplanet Survey Satellite (TESS) mission. TESS is a space telescope, designed to search for exoplanets using the transit method in an area 400 times larger than that covered by the Kepler mission.
Date of presentation: 6 Aug 2018
Subject: The TESS Mission
Description: Jeff gave a brief presentation outlining the goals and progress of NASA's Transiting Exoplanet Survey Satellite (TESS) mission. TESS is a space telescope, designed to search for exoplanets using the transit method in an area 400 times larger than that covered by the Kepler mission.
04 August 2018
Event: Drone Testing
David organized a mini-event at Baylands Park in Sunnyvale, CA. Several squadron members participating in our Quadcopter Kit AE Stem Project met at Baylands Park to fly the STEM Quad Lugs quadcopter. This quadcopter, built at the squadron by squadron members, was stable on the easy settings, near impossible to control on the sensitive settings. It will continue to fly in the future, and will be used at recruiting events. This successfully concludes this STEM project.
While there, the group also flew other member-owned quadcopters and fixed wing RC aircraft. The park had other RC modelers flying their aircraft, and the group spent quite a bit of time watching them as well.
While there, the group also flew other member-owned quadcopters and fixed wing RC aircraft. The park had other RC modelers flying their aircraft, and the group spent quite a bit of time watching them as well.
16 July 2018
Presentation: July 2018
This month's AE presenter: Jeff
Date of presentation: 16 July 2018
Subject: Light Pollution - Saving the Dark
Description: This month's AE presentation talked about light pollution - the causes (excessive lighting, poorly shielded lighting (particularly street lights)), the effects (wasted energy, perpetually glowing sky, health and other effects on both humans and wildlife), and suggestions for ways to alleviate the problem.
Date of presentation: 16 July 2018
Subject: Light Pollution - Saving the Dark
Description: This month's AE presentation talked about light pollution - the causes (excessive lighting, poorly shielded lighting (particularly street lights)), the effects (wasted energy, perpetually glowing sky, health and other effects on both humans and wildlife), and suggestions for ways to alleviate the problem.
04 June 2018
Presentation: June 2018
This month's AE presenter: David
Date of presentation: 4 June 2018
Subject: Delta-winged Aircraft
Description: Delta wings provide several important benefits. As triangular structures, they are inherently strong. Delta wings are streamlined. With supersonic aircraft, the leading edge of a delta wing can be angled so that the entire wing remains in subsonic air. Delta wings have surprisingly good low speed performance due to vortex lift, or leading edge vortexes effectively creating a highly-cambered airfoil. Delta aircraft can have conventional tails or be a tailless flying wing. If the aircraft is also a flying-wing, it will have to land at high angles of attack due to limited ability to deploy flaps.
Date of presentation: 4 June 2018
Subject: Delta-winged Aircraft
Description: Delta wings provide several important benefits. As triangular structures, they are inherently strong. Delta wings are streamlined. With supersonic aircraft, the leading edge of a delta wing can be angled so that the entire wing remains in subsonic air. Delta wings have surprisingly good low speed performance due to vortex lift, or leading edge vortexes effectively creating a highly-cambered airfoil. Delta aircraft can have conventional tails or be a tailless flying wing. If the aircraft is also a flying-wing, it will have to land at high angles of attack due to limited ability to deploy flaps.
31 May 2018
No presentation: May 2018
Events have conspired to rob our audience of our monthly brilliance for the month of May 2018. Apologies all around.
23 April 2018
Presentation: April 2018
This month's AE presenter: David
Date of presentation: 23 Apr 2018
Subject: The Stratolaunch Aircraft
Description: David gave a presentation this month on the Stratolaunch aircraft. The Stratolaunch is similar in concept to Spaceship One's mothership, the White Knight. It is a twin-boomed airplane used to carry satellite boosters to approximately 50,000 feet. The booster is then dropped for launch to low earth orbit. The Stratolaunch is the largest airplane by wingspan, with a 385 foot wing, longer than the wing of the Spruce Goose. Gross weight is over 1.3 million pounds, with a 500,000 pound payload. The airplane's six engines and many of the flight components were salvaged from two Boeing 747s. The Stratolaunch is currently undergoing high speed taxi testing. Its first flight is expected to be in 2019.
Date of presentation: 23 Apr 2018
Subject: The Stratolaunch Aircraft
Description: David gave a presentation this month on the Stratolaunch aircraft. The Stratolaunch is similar in concept to Spaceship One's mothership, the White Knight. It is a twin-boomed airplane used to carry satellite boosters to approximately 50,000 feet. The booster is then dropped for launch to low earth orbit. The Stratolaunch is the largest airplane by wingspan, with a 385 foot wing, longer than the wing of the Spruce Goose. Gross weight is over 1.3 million pounds, with a 500,000 pound payload. The airplane's six engines and many of the flight components were salvaged from two Boeing 747s. The Stratolaunch is currently undergoing high speed taxi testing. Its first flight is expected to be in 2019.
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