To obtain a high-resolution image of the stamps for media use only, e-mail roy.a.betts@usps.gov.

ST. PAUL, MN — Four American scientists today were honored on Forever stamps issued by the U.S. Postal Service during a special ceremony at the Science Museum of Minnesota.

The distinguished scientists are: chemist Melvin Calvin; botanist Asa Gray; physicist Maria Goeppert Mayer; and biochemist Severo Ochoa. The stamps go on sale nationwide at local Post Offices, online at usps.com and through the toll-free line, 1-800 782-6724.

With these stamps, the third in the American Scientists series, the Postal Service honors four Americans who, while dedicating their lives to understanding the fundamental process of nature, made extraordinary contributions to the advancement of science.

“In this small way, we have created a lasting tribute to four extraordinary scientists, and as we share their legacy with Americans everywhere, it is our fervent hope that these stamps also will help to light the spark of science in young minds everywhere,” said Pritha Mehra, Postal Service vice president, Mail Entry and Payment Technology. who dedicated the stamp.

“And, whenever you purchase these wonderful new stamps, they will be good for 1-ounce First-Class Mail postage … forever,’’ Mehra said.

Joining Mehra to dedicate the stamps were St. Paul Mayor Christopher Coleman; Science Museum of Minnesota President Eric Jolly; Distinguished McKnight University Professor George Barany; Citizens’ Stamp Advisory Committee Vice Chair Ira Michael Heyman; and St. Paul Postmaster Michael Larson.

Following is brief background information on the four American scientists honored on the new Forever stamps:

Melvin Calvin was the first scientist to trace in detail the process of photosynthesis, and he conducted pioneering research on using plants as an alternative energy source. He won the Nobel Prize in chemistry in 1961.

Asa Gray, one of the first professional botanists in the United States, advanced the specialized field of plant geography and became the principal American advocate of evolutionary theory in the mid-nineteenth century.

Maria Goeppert Mayer developed a theoretical model that helped explain the structure of the atomic nucleus; for this work she became one of only two women, the other Marie Curie, to win a Nobel Prize in physics.

Severo Ochoa, a biochemist, was the first scientist to synthesize ribonucleic acid, and he competed in the race to decipher the genetic code. Ochoa won the Nobel Prize in physiology or medicine in 1959.

For each stamp in this block of four, art director Ethel Kessler collaborated with designer, typographer and photo illustrator Greg Berger to create a collage featuring a photograph and signature of the scientist, along with items such as equations and diagrams associated with the scientist’s research.

How to Order the First-Day-of-Issue Postmark
Customers have 60 days to obtain the first-day-of-issue postmark by mail. They may purchase new stamps at a local Post Office, at The Postal Store website at usps.com/shop, or by calling 800-STAMP-24. They should affix the stamps to envelopes of their choice, address the envelopes (to themselves or others) and place them in larger envelopes addressed to:

American Scientists Stamp
Postmaster
P.O. Box 645001
St. Paul, MN 55164-5001

After applying the first-day-of-issue postmark, the Postal Service will return the envelopes through the mail. There is no charge for the postmark. All orders must be postmarked by Aug. 16, 2011.

How to Order First-Day Covers
The Postal Service also offers first-day covers for new stamp issues and Postal Service stationery items postmarked with the official first-day-of-issue cancellation. Each item has an individual catalog number and is offered in the quarterly USA Philatelic catalog. Customers may request a free catalog by calling 800-STAMP-24 or writing to:

Information Fulfillment
Dept. 6270
U.S. Postal Service
PO Box 219014
Kansas City, MO 64121-9014

Philatelic Products
There are four philatelic products available for this stamp issue:

• 467363, First-Day Cover Set of 4, $3.52
• 467368, Digital Color Postmark Set of 4, $6.40
• 467391, Ceremony Program, $6.95
• 467399, Cancellation Keepsake Stamp Pane with Digital Color Postmark Envelope, $15.95

To learn more about the Postal Service’s Stamp Program, visit http://beyondtheperf.com.

The Postal Service receives no tax dollars for operating expenses and relies on the sale of postage, products and services to fund its operations.

We’re everywhere so you can be anywhere: www.uspseverywhere.com.

# # #

Please Note: For broadcast quality video and audio, photo stills and other media resources, visit the USPS Newsroom at www.usps.com/communications/newsroom/welcome.htm.

A self-supporting government enterprise, the U.S. Postal Service is the only delivery service that reaches every address in the nation, 150 million residences, businesses and Post Office Boxes. The Postal Service receives no tax dollars for operating expenses, and relies on the sale of postage, products and services to fund its operations. We’re everywhere so you can be anywhere: www.uspseverywhere.com. With 32,000 retail locations and the most frequently visited website in the federal government, usps.com, the Postal Service has annual revenue of more than $67 billion and delivers nearly 40 percent of the world’s mail. If it were a private sector company, the U.S. Postal Service would rank 29th in the 2010 Fortune 500. Black Enterprise and Hispanic Business magazines ranked the Postal Service as a leader in workforce diversity. The Postal Service has been named the Most Trusted Government Agency six consecutive years and the sixth Most Trusted Business in the nation by the Ponemon Institute.