Showing posts with label tests. Show all posts
Showing posts with label tests. Show all posts

Tuesday, April 23, 2013

NASA Tests First Deep-Space Internet

artist concept of interplanetary internet Artist concept of interplanetary internet. Image credit: NASA/JPL
Larger view November 18, 2008

PASADENA, Calif. – NASA has successfully tested the first deep space communications network modeled on the Internet.

Working as part of a NASA-wide team, engineers from NASA's Jet Propulsion Laboratory in Pasadena, Calif., used software called Disruption-Tolerant Networking, or DTN, to transmit dozens of space images to and from a NASA science spacecraft located about more than 32 million kilometers (20 million miles) from Earth.

"This is the first step in creating a totally new space communications capability, an interplanetary Internet," said Adrian Hooke, team lead and manager of space-networking architecture, technology and standards at NASA Headquarters in Washington.

NASA and Vint Cerf, a vice president at Google, Inc., in Mountain View, Calif., partnered 10 years ago to develop this software protocol. The DTN sends information using a method that differs from the normal Internet's Transmission-Control Protocol/Internet Protocol, or TCP/IP communication suite, which Cerf co-designed.

The Interplanetary Internet must be robust enough to withstand delays, disruptions and disconnections in space. Glitches can happen when a spacecraft moves behind a planet, or when solar storms and long communication delays occur. The delay in sending or receiving data from Mars takes between three-and-a-half to 20 minutes at the speed of light.

Unlike TCP/IP on Earth, the DTN does not assume a continuous end-to-end connection. In its design, if a destination path can't be found, the data packets are not discarded. Instead, each network node keeps custody of the information as long as necessary until it can safely communicate with another node. This store-and-forward method, similar to basketball players safely passing the ball to the player nearest the basket, means that information does not get lost when no immediate path to the destination exists. Eventually, the information is delivered to the end user.

"In space today, an operations team has to manually schedule each link and generate all the commands to specify which data to send, when to send it, and where to send it," said Leigh Torgerson, manager of the DTN Experiment Operations Center at JPL. "With standardized DTN, this can all be done automatically."

Engineers began a month-long series of DTN demonstrations in October. Data were transmitted using NASA's Deep Space Network in demonstrations occurring twice a week. Engineers use NASA's Epoxi spacecraft as a Mars data-relay orbiter. Epoxi is on a mission to encounter Comet Hartley 2 in two years.

"There are 10 nodes on this early interplanetary network," said Scott Burleigh of JPL, lead software-engineer for the demonstrations. "One is the Epoxi spacecraft itself and the other nine, which are on the ground at JPL, simulate Mars landers, orbiters and ground mission-operations centers."

This month-long experiment is the first in a series of planned demonstrations to qualify the technology for use on a variety of upcoming space missions, said Jay Wyatt, manager of the Space Networking and Mission Automation Program Office at JPL. In the next round of testing, a NASA-wide demonstration using new DTN software loaded on board the International Space Station is scheduled to begin next summer.

In the next few years, the Interplanetary Internet could enable many new types of space missions. Complex missions involving multiple landed, mobile and orbiting spacecraft will be far easier to support through the use of the Interplanetary Internet. It could also ensure reliable communications for astronauts on the surface of the moon.

The Deep Impact Networking Experiment is sponsored by the Space Communications and Navigation Office in NASA's Space Operations Mission Directorate in Washington. NASA's Science Mission Directorate and Discovery Program in Washington provided experimental access to the Epoxi spacecraft. The Epoxi mission team provided critical support throughout development and operations.

JPL is managed for NASA by the California Institution of Technology in Pasadena.

Media contacts: Rhea Borja 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
rhea.r.borja@jpl.nasa.gov

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

Katherine Trinidad 202-358-1100
NASA Headquarters, Washington
Katherine.trinidad@nasa.gov

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Wednesday, April 10, 2013

First tests of old patent medicine remedies from a museum collection

What was in Dr. F. G. Johnson's French Female Pills and other scientifically untested elixirs, nostrums and other quack cures that were the only medicines available to sick people during the 18th, 19th and early 20th centuries?

Scientists provided a glimpse today based on an analysis of a museum collection of patent medicines used in turn-of-the-century America. It was part of the 245th National Meeting & Exposition of the American Chemical Society, the world's largest scientific society, which is being held here this week.

Mark Benvenuto, Ph.D, who headed the study, explained that hundreds of untested products were sold in stores, by mail order or in traveling medicine shows during the patent medicine era. The products were called "patent medicines" not because they had been granted a government patent, but from an unrelated term that originated in 17th century England.

"This was an era long before the controlled clinical trials and federal regulations that ensure the safety and effectiveness of the medicines we take today," Benvenuto explained. "Many patent medicines had dangerous ingredients, not just potentially toxic substances like arsenic, mercury and lead, but cocaine, heroin and high concentrations of alcohol."

The samples came from the collection of the Henry Ford Museum, in Dearborn, Mich. The museum houses artifacts celebrating American inventors of various items, including planes, cars, trains, machines, furniture and more. The 50 patent medicines in the analysis were among hundreds in the museum's Health Aids collection. The results of Benvenuto's study are on display at the museum.

Undergraduate students working under Benvenuto's supervision performed the bulk of the research. Andrew Diefenbach, a senior and mechanical engineering major at the university, presented the group's research in a talk here today. He got involved in the project as a freshman in Benvenuto's general chemistry course. "I'm interested to see what other comments people have, and what kind of things they may have thought of that we haven't thought of so far that we can use to further the research," Diefenbach said.

Some of the ingredients in the samples of old patent medicines, including calcium and zinc, actually could have been healthy and are mainstays in modern dietary supplements, said Benvenuto. He is with the University of Detroit Mercy. But others were clearly dangerous. Analysis of Dr. F. G. Johnson's French Female Pills, for instance, revealed iron, calcium and zinc. But the nostrum also contained lead, which is potentially toxic. Others contained mercury, another potentially toxic heavy metal, and arsenic.

Benvenuto explained that the presence of heavy metals may have been due to contamination. On the other hand, there actually was a rationale for including some of them. Arsenic and mercury were mainstays for treatment of syphilis, for instance.

Provided by American Chemical Society search and more info website


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