APOD: A Flight of Helios (2011 Jul 24)

[APOD Robot]

A Flight of Helios

Explanation: An example of solar-powered flight, NASA's Helios aircraft flew almost one hundred years after the Wright brothers' historic flight on December 17, 1903. Pictured here at 3,000 meters in in skies northwest of Kauai, Hawaii, USA in August 2001, the remotely piloted Helios is traveling at about 40 kilometers per hour. Essentially an ultralight flying wing with 14 electric motors, the aircraft was built by AeroVironment Inc. Covered with solar cells, Helios' impressive 247 foot wide wing exceeded the wing span and even overall length of a Boeing 747 jet airliner. Climbing during daylight hours, the prototype aircraft ultimately reached an altitude just short of 30,000 meters, breaking records for non-rocket powered flight. Helios was intended as a technology demonstrator, but in the extremely thin air 30,000 meters above Earth's surface, the flight of Helios also approached conditions for winged flight in the atmosphere of Mars.

<< Previous APOD

Discuss Any APOD

Next APOD >>

[/b]

[neufer]

---

[Ann]

This is a quite lovely picture. It is a beautiful thing that humans have managed to build solarpowered aircraft, let alone one that could fly as high as this one.

But I wonder if it will ever be possible to build commercial airplanes with this technique.

Ann

[Guest]

At a cost to taxpayers of .... ?????

NASA needs to start printing that below its logo.

[owlice]

At a cost to taxpayers of .... ?????

....$55 per year?

I'd gladly pay quite a bit more if the extra went entirely to NASA.

[Davmkris]

Are the distances as stated correct? 3,000 meters is believable at about 10,000 feet. But 30,000 meters puts it well above 100,000 feet. For real?

[orin stepanek]

Are the distances as stated correct? 3,000 meters is believable at about 10,000 feet. But 30,000 meters puts it well above 100,000 feet. For real?

2001 August 14 96,863 ft 29.524 km Unmanned NASA Helios HP01 propeller solar-electric aircraft - record for non-rocket plane

[neufer]

Are the distances [sic] as stated correct? 3,000 meters is believable at about 10,000 feet.
But 30,000 meters puts it well above 100,000 feet. For real?

Yep

Fixed-wing propeller driven aircraft altitude records

Code: Select all

Year 	Altitude 	Person 	Aircraft 	Power
........................................................
1903 	3 m 		Wilbur Wright, Orville Wright 	Wright Flyer 	
1906 	4 m 		Alberto Santos-Dumont 	14-bis 	
1908 	110 m 		Wilbur Wright 	Biplane 	
1909 	920 m 		Louis Paulhan 	Farman 	
1910 	1,269 m 	Louis Paulhan 	Farman 	
1910 	1,403 m 	Walter Brookins 	Wright biplane 	
1910 	2,582 m 	Ralph Johnstone 	Wright biplane 	
1915 	3,640 m 	Joseph Eugene Carberry 	 ? 	
1920 	10,093 m 	Major Rudolf Schroeder 	LUSAC-11 	
1921 	10,518 m 	Lieutenant John Arthur Macready 	LUSAC-11 	
1930 	13,158 m 	Lieutenant Apollo Soucek, USN 	Wright Apache 	
1932 	13,404 m 	Cyril Unwins 	Vickers Vespa 	
1933 	13,661 m 	Gustave Lemoine 	Potez 50 	
1934 	14,433 m 	Renato Donati 	Caproni Ca.113 	
1936 	15,230 m 	Squadron Leader Francis Ronald Swain 	Bristol Type 138 	
1938 	16,440 m 	M. J. Adam 	Bristol Type 138 	
1938 	17,083 m 	Lieutenant Colonel Mario Pezzi 	Caproni Ca.161 	manned  record to date	
2001 	29.524 km 	NASA Helios HP01 	 	solar-electric aircraft - record for non-rocket plane

- The conquest of the world record height - October 22, 1938

---

- The device a Caproni 161 - Air which has been achieved the world record height of piston aircraft, a record still unbeaten (17.083m)

---

<<Mario Pezzi (1898-1968) was an Italian aviator known worldwide for his flight in which he achieved greater height than any other pilot in a propeller-powered airplane.

The future lieutenant general was born November 9, 1898. He had one brother, Enrico, who also grew up to be a General in the Italian Air Force. Mario joined the Infantry in October 1917, and the next year earned the rank of second lieutenant. He received his pilot's license in 1926. The next year he became part of the General Staff, rising to Cabinet of the Defense Ministry in 1931.

On May 7, 1937, Maj. Mario Pezzi took off from the Guidonia-Montecelio base on a Caproni Ca161 aircraft powered by a 14 cyl. double stellar engine supercharged by a double centrifugal 750 hp compressor. Piloting this aircraft he climbed to 15,655 m. Pezzi wore a special electrically heated pressurized suit and an airtight helmet, just like a modern astronaut. In the Caproni hangars in the meantime work went on ceaselessly to produce a new version of the aircraft, the Ca161bis designed by engineer Verduzio. Its cockpit embedded an air-tight shell, the first one to be built in the history of flight. The great expectations on this machine were soon fulfilled: on October 22, 1938, Pezzi attained a new world record of altitude in a propeller-driven, piston-engined aircraft (17,083 m), record still unbeaten today.

Transferred to the command of the East African Air Force, he commanded the base of Dire Dawa in 1941 and was appointed Chief of Staff of East Africa. He was taken prisoner at Amba Alagi on 20 May 1941. After the Sept. 8 switch to the south and in December 1943 assumed command of Unity Air operate until February 1945. In September 1948 he was appointed Director General of the staff Military Air Force. From June 1950 to February 1955 he was head of Cabinet Minister and then Secretary General of the Air. Pezzi is rightly considered an aeronautics and astronautics pioneer in Italy not only for his altitude records: he was the man who chose Luigi Broglio to lead the ITAF Ammunition Research Unit, responsible for rockets and missiles research, leading the way to future space exploration in Italy. He died in Rome on August 26, 1967.

[biddie67]

Such an unwieldy looking machine - I'm glad that it managed to reach the altitude it did but it sure doesn't look as though it can handle any atmospheric turbulance, storms, etc.

The kicker sentence in the APOD was the last sentence ::

Helios was intended as a technology demonstrator, but in the extremely thin air 30,000 meters above Earth's surface, the flight of Helios also approached conditions for winged flight in the atmosphere of Mars.]

This made my "ears perk up" - the force of gravity must be less on Mars which would be a plus but sunlight surely wouldn't be as strong as in Hawaii which would be a minus. Not to even mention packing and transporting such an unwieldy piece of equipment to Mars and then assembling it there! As stated above, definitely a "wing and a prayer" situation.

But, WOW, if NASA, et al. could come up with solar panels so efficient for something like this, I'd be among the first in line for the car using them here!!

[moonstruck]

Go NASA go !!

[nstahl]

They'd better get Martian weather forecasting down well. It doesn't look like it would survive in one of their windstorms, unless maybe it could get above it or at least above the vorticity, shears and downdrafts.

If I could steer my tax money some would go to NASA, some to other things we need and a lot less to some things that just hurt us. But it doesn't work that way.

[biddie67]

Wouldn't it be interesting, if on our annual income tax forms, besides the checkbox for $3.00 going to the Presidential Election Fund, there would be checkboxes where we could also check off $$$ designated to NASA and perhaps other projects of special concern ....

[Chris Peterson]

At a cost to taxpayers of .... ?????

NASA needs to start printing that below its logo.

It's hard to imagine any publicly funded venture that has provided a greater return on investment than NASA. If they are going to put numbers under their logo, they will reflect a net gain, not a cost.

[neufer]

Such an unwieldy looking machine - I'm glad that it managed to reach the altitude it did but it sure doesn't look as though it can handle any atmospheric turbulance, storms, etc.

They'd better get Martian weather forecasting down well. It doesn't look like it would survive in one of their windstorms, unless maybe it could get above it or at least above the vorticity, shears and downdrafts.

---

---

Bruegel's Landscape with the Fall of Icarus (ca. 1558), famous for relegating the fall to a scarcely noticed event in the background

---

<<On June 26, 2003, the Helios Prototype broke up and fell into the Pacific Ocean about ten miles (16 km) west of the Hawaiian Island Kauai during a remotely piloted systems checkout flight in preparation for an endurance test scheduled for the following month.

On the morning of the accident, weather forecasts indicated that conditions were inside the acceptable envelope, although during the preflight go/no-go review, the weather forecaster gave it a "very marginal GO." One of the primary concerns was a pair of wind shear zones off the island's coast. After a delayed take off, due to the failure of the winds to shift as predicted, Helios spent more time than expected flying through a zone of low-level turbulence on the lee side of Kauai, because it was climbing slower than normal, since it had to contend with cloud shadows and the resultant reduction in solar power.

As the aircraft climbed through 2,800 feet (850 m), according to the subsequent mishap investigation report, "At about 30 minutes into the flight, the aircraft encountered turbulence and morphed into an unexpected, persistent, high dihedral configuration. As a result of the persistent high dihedral, the aircraft became unstable in a very divergent pitch mode in which the airspeed excursions from the nominal flight speed about doubled every cycle of the oscillation. The aircraft’s design airspeed was subsequently exceeded and the resulting high dynamic pressures caused the wing leading edge secondary structure on the outer wing panels to fail and the solar cells and skin on the upper surface of the wing to rip off. The aircraft impacted the ocean within the confines of the PMRF test range and was destroyed. Most of the vehicle structure was recovered except the hydrogen–air fuel cell pod and two of the ten engines, which sank into the ocean."

The investigation report identified a two-part root cause of the accident:

"Lack of adequate analysis methods led to an inaccurate risk assessment of the effects of configuration changes leading to an inappropriate decision to fly an aircraft configuration highly sensitive to disturbances."

"Configuration changes to the aircraft, driven by programmatic and technological constraints, altered the aircraft from a spanloader to a highly point-loaded mass distribution on the same structure significantly reducing design robustness and margins of safety.">>

[bystander]

APOD: The Flight of Helios (2007 Jul 22)
APOD: The Flight of Helios (2003 Dec 20)
APOD: The Flight of Helios (2001 Aug 31)
http://asterisk.apod.com/viewtopic.php? ... 85#p153131

[drollere]

relevance to astronomy: 0%
chances similar technology will be deployed on mars within a century: 0%
out of office messages from APOD selection committee: 100%

[saturn2]

NASA´s Helios aircraft flew at around 40 Km / hour, and 3000 meters in the sky of Hawaii.
It´s solar powered.
In the space the solar wind move the spacecrafts of solar sails.

[Chris Peterson]

relevance to astronomy: 0%
chances similar technology will be deployed on mars within a century: 0%

I disagree. Assuming we continue to explore Mars, I think the likelihood of solar powered aircraft on the planet is quite high. We are also likely to see fleets of aircraft similar to this cruising our own atmosphere, as Earth observation tools- which is certainly relevant to astronomy.

[Chris Peterson]

In the space the solar wind move the spacecrafts of solar sails.

Solar wind is a minor contributor to the propulsion generated by solar sails. The force comes mainly from radiation pressure.

[neufer]

relevance to astronomy: 0%
chances similar technology will be deployed on mars within a century: 0%

I disagree. Assuming we continue to explore Mars, I think the likelihood of solar powered aircraft on the planet is quite high.

The ARES full-scale and half-scale flight test vehicles.

---

---

We are also likely to see fleets of aircraft similar to this cruising our own atmosphere, as Earth observation tools- which is certainly relevant to astronomy.

It is certainly relevant to saving taxpayer dollars for all sorts of current & future earth observations.

[neufer]

In the space the solar wind move the spacecrafts of solar sails.

Solar wind is a minor contributor to the propulsion generated by solar sails. The force comes mainly from radiation pressure.

<<There are two sources of solar forces: radiation pressure, and solar wind. Radiation pressure is much stronger than wind pressure. Both of these forces are small and decrease with the inverse square distance from the Sun.

In 1924, the Russian space engineer Friedrich Zander proposed that, since light provides a small amount of thrust, this effect could be used as a form of space propulsion requiring no fuel. Einstein proposed (and experiments confirm) that photons have a momentum p=E/c; therefore, each light photon absorbed by or reflecting from a surface exerts a small amount of radiation pressure. This results in forces of about 4570 mN/km² (~ 1 pound of force per square kilometer of sail) for absorbing surfaces perpendicular to the radiation in Earth orbit, and twice as much if the radiation is reflected.

Charged particles from the solar wind are able to point the ion tails of comets away from the Sun. The solar wind averages 6.7 billion tons per hour at 520 km/s with "slow" low energy coronal ejections reaching 400 km/s and "fast," higher energy ejections averaging 750 km/s. At the distance of the Earth, this results in average solar wind pressure of 3.4 mN/km², and is three orders of magnitude less than the photonic radiation pressure. Still the solar wind dominates many phenomena because its interaction cross section with gases and charged particles is about 10⁹ times larger than that of the photons.>>

<<The Dawn spacecraft (now orbiting Vesta) is propelled by three xenon ion thrusters which produce a thrust of 90 mN.>>

[Ann]

Wow, I love that Brueghel painting of the fall of Icaros. I think it says so much about the human condition. Say what you will, it is a beautiful painting, a tribute to the beauty of the Earth, a tribute to human toil and hard work, and a tribute to our enterprising spirits, lofty dreams, and frail bodies. And a reminder that every person is mortal and will be, and must be, forgotten, as society goes on regardless of the tragedies of individuals.

Ann

[kingernie]

And the payload was what?

I guess I missed that part. In my experience*, a proof of concept (POC) always required a payload of some kind. Even the Soviets were aware of that - a transmitter sending out beeps in Sputnik I, and a dog in one of their later endeavors. To compare this to the grand achievement of the Wright brothers is insulting. The brothers received NO taxpayer supplied monies in their initial development of viable heavier than air craft.

*Thirty-three years in aerospace engineering at The Aerospace Corporation. The opinions expressed are my own, and I am not representing the corporation.

[Chris Peterson]

And the payload was what?

The instrumentation that monitored performance, recorded it, sent the data back to the ground. That is a very typical payload for test flights of unmanned aircraft (and consistent with the likely payload a craft like this would carry in any real application). Of course, other than ensuring some sort of design loading, no payload as such is required for a test flight if the goal is to measure performance of control surface movement, the avionics, etc.

To compare this to the grand achievement of the Wright brothers is insulting. The brothers received NO taxpayer supplied monies in their initial development of viable heavier than air craft.

I don't believe such a comparison was being made. Of course, the Helios is a much greater achievement if a comparison were to be made. The Wright brothers were marginally the first of many people all working towards an inevitable goal that would have been reached with or without them in short order- a goal reached with rather crude methodologies. Helios is a masterpiece of scientific and engineering innovation.

As far as taxpayer money is concerned... while the Wright Brothers may have received none, most of the rapid development in aviation that followed in the next decades was largely funded by military spending.

*Thirty-three years in aerospace engineering at The Aerospace Corporation. The opinions expressed are my own, and I am not representing the corporation.

A company that would be a shadow of its present self without massive taxpayer investment...

[saturn2]

Chris Peterson and Neufer thank by your explanations
There are two solar forces; radiation pressure and wind pressure.
This forces can to move spacecrafs in the future.