It’s hard to believe it’s been twenty years already. We are farther removed in time from the Challenger explosion than that day was from the moon landing. Yet we’re still flying the same shuttles, which one astronaut recently called a “deathtrap.” Here’s an interesting article on what we’ve learned (or what we think we’ve learned) since then.

That night twenty years ago President Ronald Reagan was eloquent in a way impossible to imagine recent presidents emulating:

There’s a coincidence today. On this day three hundred and ninety years ago, the great explorer Sir Francis Drake died aboard ship off the coast of Panama. In his lifetime the great frontiers were the oceans, and a historian later said, “He lived by the sea, died on it, and was buried in it.” Well, today, we can say of the Challenger crew: Their dedication was, like Drake’s, complete.

The crew of the space shuttle Challenger honored us by the manner in which they lived their lives. We will never forget them, nor the last time we saw them, this morning, as they prepared for their journey and waved goodbye and “slipped the surly bonds of earth” to “touch the face of God.”

Launched little over a year ago, the Messenger spacecraft sped by the Earth last month on its way to Venus and Mercury, using Earth’s gravity like a slingshot to pick up speed. Scientists assembled into a short movie a series of photos from the spacecraft, in which a glistening Earth recedes in the distance.