The Afternoon Constellation - A-Train


The formation of satellites — which currently includes Aqua, CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and Aura satellites — barrels across the equator each day at around 1:30 p.m. local time each afternoon, giving the constellation its name; the "A" stands for "afternoon."

An Expedition to Earth
New Scientist Jul 29, 1989

The phrase "Mission to Planet Earth" became popular in 1987 when Sally Ride, the US's first woman astronaut and a scientiat at Stanford University in California, headed a study for NASA [Ride Report ~ The Ride Report also recognizes the risks of making the Space Station dependent on one single launch vehicle - the Space Shuttle. It proposes the development of a shuttle-derived cargo launcher, as a way of diversifying the launch fleet.]. Mission to Planet Earth was one option her group looked at to restore the US's leadership in space after the Challenger disaster. NASA has now adopted its own version of the mission and plans to ask Congress for money to being the first stage — the Earth Observing System.

Societal Impact of Spaceflight
Edited by Steven J. Dick and Roger D. Launius

PDF available at NSS: Space Policy Library: Part III: NASA Compendiums on Space and Culture

NASA also engaged in its own reappraisal of the future of human spaceflight. astronaut Sally Ride chaired an internal agency planning group that prepared a report on Leadership and America’s Future in Space. It, too, proposed an eventual human mission to Mars, but at a more measured pace and scale than the national commission had proposed. these and other studies were gestures toward a transformational vision of human spaceflight beyond the Shuttle era, but they were not converted to action plans.

Near the one-year anniversary of the Challenger accident, an encouraging piece by space scientist Carl Sagan appeared in The New York Times.“It’s time to go to Mars,” he wrote ["It's Time to Go to Mars," New York Times, Op-Ed, p. A27, Jan. 23, 1987], in a systematic program of exploration advancing from robotic rovers to sample-return missions and then to “the first human footfalls on another planet.” unlike the national commission’s vision of productive industry on mars, Sagan’s vision focused on the values of adventure, excitement, inspiration, valor, prestige, and purpose in the space frontier. he argued that exploration of mars for the sake of knowledge could revitalize the moribund space program and make possible a new goal,“establishing humanity as a multiplanet species."

Variants of the exploration of Mars arose as forces inside and outside NASA tried to reframe the purpose of human spaceflight. The Mars goal seemed a worthy commitment for astronauts, and it might align the human and robotic flight programs in a complementary rather than competitive enterprise. It could also reassert American leadership in space in an inspiring, challenging adventure. By spring, 1987, John Noble Wilford could report in The New York Times that “momentum is building in the space agency and among… leaders to make Mars the next major goal of the American civilian space program.” Exploration, specifically the exploration of Mars, had gained credibility and resonance as the future meaning of human spaceflight.

The 20th anniversary of the Apollo 11 landing highlighted the discrepancy between current human spaceflight and aspirations for a new purpose. President George H. W. Bush marked the anniversary in 1989 by endorsing a spacefaring initiative to return to the Moon and move on to Mars. Apparently formalizing the frame shift from Shuttle-era concepts to exploration, the announcement was more rhetoric than mandate, for he set no schedule and made no funding commitment for such an enterprise. It met with skepticism among political leaders and space policy analysts as too costly. The New York Times dismissed it as “Mr. Bush’s giant step back in space… a failure of imagination” because it sounded like Apollo redux without a compelling reason. The president’s new frame for the meaning of human spaceflight seemed rickety but it did authorize NASA to chart a path out of Earth orbit through a new space exploration initiative.

Budget of NASA

National Aeronautics and Space Administration (PDF)
Budget of the United States Government: Browse Fiscal Year 2011

NASA’s Constellation program—based largely on existing technologies—was begun to realize a vision of returning astronauts back to the Moon by 2020. However, the program was over budget, behind schedule, and lacking in innovation due to a failure to invest in critical new technologies. Using a broad range of criteria, an independent review panel determined that even if fully funded, NASA’s program to repeat many of the achievements of the Apollo era, 50 years later, was the least attractive approach to space exploration as compared to potential alternatives. Furthermore, NASA’s attempts to pursue its Moon goals had drawn funding away from other NASA programs, including robotic space exploration, science, and Earth observations. The President’s Budget cancels Constellation and replaces it with a bold new approach that invests in the building blocks of a more capable approach to space exploration…