In The Big Bang Theory, NASA has tasked Howard with his various missions, building things to go into space, journeying to the space station, making speeches and representing NASA as one of their astronauts. Howard aslo works the Jet Propulsion Lab, a NASA facility.
In "The Lizard-Spock Expansion", Howard wrecks the NASA Mars rover and then erases all the evidence. Later his actions cause NASA to discover that there was life on Mars, but does't know who to thank.
In "The Russian Rocket Reaction", NASA asks Howard to go to the space station to install the telescope he designed.
In "The Werewolf Transformation", Howard reports to Houston for his astronaut training which he suffers through. In "The Friendship Contraction", Howard's show the guys the official NASA press release announcing his mission to the space station.
In "The Launch Acceleration", NASA cancels and then reschedules Howard's mission at the space station.
In "The Countdown Reflection", Howard flies into space aboard a Russian rocket to get to the space station.
In "The Holographic Excitation", Howard gives out autographed copies of his official NASA protrait.
In "The Table Polarization", NASA asks Howard to return to the space station to repair the telescope which he is excited about. Bernadette has an intervention to convince him not to go since he was so miserable there.
In "The Friendship Turbulence", Howard offers to take Sheldon to Houston for a tour of NASA headquarters.
In "The Mommy Observation", Howard gives a talk at NASA's Houston Manned Spacecraft Center and gives Sheldon a tour.
In "The First Pitch Insufficiency", Howard represents NASA on Space Day to throw out the first pitch at a Los Angeles Angels baseball game.