“The test flights are over”

President Reagan at STS-4 landingSpace Shuttle Columbia lands at Edwards Air Force Base in California, making its first-ever landing on a concrete runway. After greeting the returning astronauts and inspecting the shuttle, President Ronald Reagan – with the partially-dismantled prototype Enterprise as a backdrop – declares NASA’s Space Shuttle system fully operational, saying “the test flights are over.” Columbia Commander Ken Mattingly later reveals that there was tremendous pressure on NASA to land Columbia on Independence Day, regardless of how many mission objectives had been met, to maximize the publicity value of the President’s speech. But the quick turnaround time and almost-weekly flight schedule that NASA had publicized throughout the 1970s is already a pipe dream: post-mission the four missions flown so far prove that post-landing servicing of each orbiter takes longer than expected. Columbia won’t fly again until the first “operational” mission in November.

Pathfinder bounces onto Mars

PathfinderUsing a never-before-attempted system of landing, the Mars Pathfinder unmanned probe employs an aerobraking maneuver to slow down in the planet’s atmosphere, and an all-encompassing layer of airbags to “bounce” onto the surface without using rockets to slow the vehicle down. The weighted landing station rolls to the correct orientation, deflates the airbags, and deploys on schedule, proving the merits of a landing technique that will deliver future Mars landers already in the planning stages.

Colliding with Deep Impact

Deep Impact at Comet Tempel 1After months on a precise interception course, NASA’s unmanned Deep Impact space probe meets up with Comet Tempel 1, firing a impactor into the comet’s nucleus to study the distribution and composition of the debris scattered by the resulting impact. The impactor had been released by the flyby spacecraft six days earlier, and transmitted its images and readings to the flyby vehicle, which records them and retransmits them to ground controllers on Earth. The two vehicles’ on-board software tracks the comet so precisely that the impact happens within a second of the anticipated timeline in the mission plan, kicking up enough cometary dust to obscure the view of the crater left on the comet’s nucleus. Following the Tempel 1 mission, the still-intact Deep Impact flyby vehicle is redirected for future missions to other objects in the solar system.

STS-121

DiscoveryNASA launches Space Shuttle Discovery for the first time in nearly a year for a second “Return to Flight” mission to the International Space Station, testing more safety procedures and new materials developed since the July 2005 flight (which still required repairs to be conducted in orbit). Aboard Discovery are Commander Steven Lindsey, Pilot Mark Kelly, and mission specialists Stephanie Wilson, Michael Fossum, Piers Sellers, Thomas Reiter and Lisa Nowak. Reiter remains aboard the station, bumping its crew up to three people for the first time since 2003.

New Horizons’ last-minute scare

PlutoNASA’s New Horizons abruptly loses contact with Earth-based ground controllers and then signals that it has gone into safe mode, ten days before its closest flyby of Pluto. In this mode, the spacecraft gathers no scientific data, and awaits intervention from Earth, but its distance from Earth – four billion miles away – means that signals transmitted to or from New Horizons take four and a half hours to reach their destination (and any reply takes just as long). A timing error is located in New Horizons’ automatic event sequencer, a vital part of its mission since it will need to operate independently to conduct hundreds of observations of Pluto and its satellites with no contact from Earth until later, and the probe is rebooted within 48 hours. Though the probe’s automatic switch to failsafe mode has cost the mission some scientific observations, most of the high-value data will not be collected until within 24 hours of closest approach on July 14th.

Juno arrives at Jupiter

JunoNASA’s Juno space probe successfully pulls of a risky orbital insertion maneuver, slowing itself down just enough to be captured into an unprecedented polar orbit around Jupiter. Launched in 2011, Juno’s first close pass of Jupiter brings it within 3,100 miles of Jupiter’s cloudtops, the closest any spacecraft has ever approached the huge planet. Its polar orbit will allow it to reduces its exposure to Jupiter’s intense magnetic field, which is powerful enough in the planet’s equatorial regions to damage or destroy on-board electronics. Juno’s mission is expected to last 20 months.