The latest updates appear at the bottom. [Latest July 2.] This was the initial release from the U.S. Postal Service:
Sally Ride 
America’s first woman in space, Sally Ride (1951–2012), inspired the nation as a pioneering astronaut, brilliant physicist and dedicated educator.
This stamp will be issued May 23rd in La Jolla, Calif., where she lived until her death at the age of 61 in 2012. More on Sally Ride can be found at Wikipedia.
[USPS advisory, March 21]
U.S. Postal Service to Dedicate Sally Ride Forever Stamp
WHAT: First-day-of-issue dedication ceremony for the Sally Ride Forever stamp. The event is free and open to the public. Please share the news using the hashtags #SallyRideForever and #AstronautStamps.
RSVP for the ceremony: Click here.
WHO:
- Megan J. Brennan, Postmaster General and Chief Executive Officer
- Pradeep K. Khosla, chancellor, University of California San Diego
- Billie Jean King, tennis legend and champion of social justice; friend of Sally Ride
- Ellen Ochoa, first Hispanic woman in space and director of the Johnson Space Center; friend of Sally Ride
- Tam O’Shaughnessy, co-founder and executive director of Sally Ride Science at University of California San Diego; widow of Sally Ride
- Becky Petitt, vice chancellor for Equity, Diversity and Inclusion, University of California San Diego
WHEN: Wednesday, May 23 at 5 p.m. PDT
WHERE: The Price Center, University of California San Diego
9500 Gilman Drive
La Jolla, CA 92093
Followers of the U.S. Postal Service’s Facebook page can view the ceremony live at facebook.com/USPS.
BACKGROUND: America’s first woman in space, Dr. Sally Ride (1951–2012) inspired the nation as a pioneering astronaut, brilliant scientist, and dedicated educator.
On June 18, 1983, Ride launched through Earth’s atmosphere aboard space shuttle Challenger, becoming the first American woman to reach space. For six days, she worked closely with her four male crewmates, proving to the world below that women were just as adept as their male counterparts in the final frontier.
Ride was the only person to sit on the investigative panels for both the Challenger and Columbia accidents. As a professor, she used her experience as an astronaut to explain complicated physics principles. In 2001, she cofounded a company devoted to fostering interest and skills in science, technology, engineering, and math among young people, particularly girls.
Through her love of science and determination to improve our world, Ride left a lasting impact on generations of students and the future of American space exploration.
After the stamp dedication ceremony, Sally Ride Science at UC San Diego will celebrate the occasion with a panel discussion on Women in Leadership at 6:30 p.m. Visit Sally Ride Science at UC San Diego for more information.
The panel discussion will feature King, Ochoa and former U.S. Secretary of State Condoleezza Rice. Lynn Sherr serves as the moderator. —VSC
Updated April 2, 2018:
Ride’s NASA biography says she was a stamp collector!
Updated April 15:
On May 23, 2018, in La Jolla, CA, the U.S. Postal Service® will issue the Sally Ride stamp (Forever® priced at the First-Class Mail® rate) in one design, in a pressure-sensitive adhesive pane of 20 stamps (Item 477300). The stamp will go on sale nationwide May 23, 2018.
America’s first woman in space, Dr. Sally Ride (1951–2012), inspired the nation as a pioneering astronaut, brilliant physicist, and dedicated educator. The stamp art, sketched first in charcoal and then rendered in oil paint, features a colorful portrait of Ride in her light blue space suit with a dramatic depiction of a space shuttle lifting off in the background. Art director Ethel Kessler designed the stamp with artwork by Paul Salmon.
Availability to Post Offices: Item 477300, Sally Ride (Forever Priced at the First-Class Mail Rate) Commemorative Pane of 20 Stamps: Stamp Fulfillment Services will make an automatic push distribution to Post Offices™ of a quantity to cover approximately 30 days of sales.
How to Order the First-Day-of-Issue Postmark:
Customers have 120 days to obtain the first-day-of-issue postmark by mail. They may purchase new stamps at their local Post Office or at The Postal Store® website at usps.com/shop. They must affix the stamps to envelopes of their choice, address the envelopes (to themselves or others), and place them in a larger envelope addressed to:
FDOI – Sally Ride Stamp
USPS Stamp Fulfillment Services
8300 NE Underground Drive, Suite 300
Kansas City, MO 64144-9900
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 up to a quantity of 50. There is a 5-cent charge for each additional postmark over 50. All orders must be postmarked by September 23, 2018.
Philatelic products for this stamp issue are as follows:
- 477306 Press Sheet with Die-cut, $90.00.
- 477310 Digital Color Keepsake, $11.95.
- 477316 First-Day Cover, $0.94.
- 477321 Digital Color Postmark, $1.65.
- 477330 Ceremony Program, $6.95.
Technical Specifications:
Issue: Sally Ride Stamp
Item Number: 477300
Denomination & Type of Issue: First-Class Mail Forever
Format: Pane of 20 (1 design)
Series: N/A
Issue Date & City: May 23, 2018, La Jolla, CA 92037
Art Director: Ethel Kessler, Bethesda, MD
Designer: Ethel Kessler, Bethesda, MD
Typographer: Ethel Kessler, Bethesda, MD
Artist: Paul Salmon, Burke, VA
Modeler: Joseph Sheeran
Manufacturing Process: Offset, Microprint
Printer: Ashton Potter (USA) Ltd. (APU)
Printed at: Williamsville, NY
Press Type: Muller A76
Stamps per Pane: 20
Print Quantity: 20,000,000 Stamps
Paper Type: Nonphosphored Type III, Block Tag
Adhesive Type: Pressure-sensitive
Processed at: Ashton Potter (USA) Ltd. (APU)
Colors: Black, Cyan, Magenta, Yellow, PMS 7687
Stamp Orientation: Vertical
Image Area (w x h): 1.085 x 1.42 in/27.56 x 36.07 mm
Overall Size (w x h): 1.225 x 1.56 in/31.12 x 39.62 mm
Full Pane Size (w x h): 7.12 x 8.14 in/180.85 x 206.76 mm
Press Sheet Size (w x h): 21.36 x 25.295 in/542.54 x 642.49 mm
Plate Size: 180 stamps per revolution
Plate Numbers: “P” followed by five (5) digits
Marginal Markings:
Front: Header: SALLY USA RIDE • Plate numbers in two corners
Back: ©2017 USPS • USPS Logo • Two barcodes (477300) • Plate Position Diagram • Promotional Text
For Jim Sutton, regarding nametags: 
It appears the actual nametag, at least for this flight, read just “Sally.”
Updated May 9th:
The link for first-day ceremony reservations was added above… or click here.
Updated July 2nd:
The Scott Catalogue number for this stamp is 5283.
On April 6, 2018, in Washington, DC, the U.S. Postal Service ® will issue the STEM Education stamps (Forever ® priced at 50 cents) in four designs, in a pressure-sensitive adhesive (PSA) pane of 20 stamps (Item 477600). The stamps will go on sale nationwide April 6, 2018. The STEM Education pane of 20 stamps may not be split or sold individually.
What: 
Followers of the U.S. Postal Service’s Facebook page can view the ceremony live at facebook.com/USPS.
directed to Hall E on the upper level of the Convention Center for the dedication ceremony.
Fred Rogers (1928-2003) was known as a beloved television neighbor to generations of children. His groundbreaking public television series “Mister Rogers’ Neighborhood” inspired and educated young viewers with warmth, sensitivity and honesty.
There are both Digital Color and pictorial first-day postmarks for this issue. In addition, local post offices may use this postmark:
The Digital Color Postmark measures 2.43″ x 1.43″
The pictorial postmark for this issue measures 2.33″ x 1.49″ 
On March 5, 2018, in Springfield, IL, the U.S. Postal Service will issue the Illinois Statehood First-Class Mail stamp (Forever priced at 50 cents) in one design, in a pressure-sensitive adhesive (PSA) pane of 20 stamps (Item 477100). The stamp will go on sale nationwide March 5, 2018.
The Digital Color Postmark measures 1.86” x 1.45”
The pictorial postmark for this issue measures 2.73” x 1.49” 
The special (local) postmark measures 2.64” x .94”
On each row of stamps, the third and fourth stamps repeat the first two designs. The selvage also features the transparent deep-sea comb jelly (photo by Gregory G. Dimijian) and the firefly squid (photo by Danté Fenolio). Art director Derry Noyes designed the stamps and selvage from existing photographs.
e postmark by mail. They may purchase new stamps at their local Post Office, at The Postal Store website at 
There are 7 
The stamps are unveiled at the Sunrise Theater in Fort Pierce, FL. Left to right, Jeffrey C. Williamson, Chief Human Resources Officer and Executive VP, USPS; Jill Roberts, News Director, WQCS Public Radio; Dr. Edith Widder, CEO and Senior Scientist, Ocean Research & Conservation Association (ORCA); Taylor F. Lockwood, stamp photographer. 
Williamson and other dignitaries sign autographs after the ceremony. 
A set of 10 first day covers canceled at the event. 
The Digital Color Postmark measures 2.97” x 1.38”
The pictorial postmark for this issue measures 2.91” x 1.47”
On February 9, 2018, in Ft. Lauderdale, FL, the U.S. Postal Service® will issue the U.S. Flag 2018 First-Class Mail® stamp (Forever® priced at 50 cents) in one design, in a pressure-sensitive adhesive (PSA) booklet of 20 stamps (Item 678200) produced by security printers Ashton Potter (USA) Ltd (APU) and Banknote Corporation of America (BCA), and a PSA Coil of 100 stamps (Item 749700) produced by security printers APU and BCA. The stamp will go on sale nationwide February 9, 2018.
It measures 2.95” x .95”.
Background: 
It measures 2.41” x 1.47”. Here is the design for the pictorial first-day postmark: 
It measures 2.95” x 1.40″. Here is the design for the “special” postmark local post offices may use for this issue: 
It measures 2.82” x 1.48”
Updated February 28th:
The Year of the Dog stamp is the 11th of 12 stamps in the Celebrating Lunar New Year series. The Year of the Dog begins Feb. 16, 2018, and ends Feb. 4, 2019.
What:
It measures 3” x 1.64”.
It measures 2.86”x 1.30”. This is the first Lunar New Year stamp issued by the U.S. with a pictorial first-day “rubber composition” postmark.
It measures 2.9” x 1”
Background:
It measures 3″ x 1.56″. Here is the design for the B&W pictorial first-day postmark:
It measures 2.85″ x 1.63″
