This year marks the 25th anniversary of the loss of NASA's Challenger space shuttle. Just 73 seconds after the launch on Jan. 28, 1986, a booster engine failed and caused the shuttle Challenger to break apart, taking the lives of all seven crew members. The spacecraft broke apart over the Atlantic Ocean, off the coast of central Florida at 11:38 am EST. (CLICK HERE TO VIEW SLIDESHOW OF THE DISASTER)

On this Day of Remembrance, as we honor our fallen heroes with tributes and public ceremonies, I will take part in a wreath-laying ceremony at Arlington National Cemetery. Across the country, flags at NASA Headquarters and the NASA centers will be flown at half-mast in memory of our colleagues lost in the cause of exploration, NASA Administrator Charles Bolden, Jr. said.

This year marks the 25th anniversary of the loss of Challenger -- a tragedy that caused us to completely re-think our systems and processes as we worked to make the shuttle safer. The nation will never forget Jan. 28, 1986, nor its indelible images. The astronauts in that crew were personal friends of mine, as were the astronauts aboard Columbia when it was lost, NASA Administrator said.

On Friday morning, NASA officials will gather at Florida's Kennedy Space Center to mark the gloomy anniversary. Special guests include the widow of Challenger's commander, June Scobee Rodgers, who will be the featured speaker at the outdoor ceremony, according to Associated Press. Rodgers was instrumental in establishing the Challenger Center for Space Science Education.

On Jan. 28, 1986 at 5 pm EST, U.S. President Ronald Reagan eulogized the crew, quoting from the poem High Flight: We will never forget them, nor the last time we saw them, this morning, as they prepared for the journey and waved goodbye and 'slipped the surly bonds of earth' to touch the face of God.

On this day 390 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 an 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, Reagan said after the disaster.

The crew members of NASA's second space shuttle Challenger were commander Francis Scobee, pilot Michael Smith, mission specialists Judith Resnik, Ellison Onizuka, Ronald McNair, Gregory Jarvis, and Christa McAuliffe, who was selected to be the first teacher in space.

Challenger was named after two previous vessels: a British corvette HMS Challenger that was the command ship for the Challenger Expedition undertaken from 1872 through 1876; and the Apollo 17 lunar module Challenger, which landed on the Moon in 1972.

Following its first flight in April 1983, Challenger quickly became the workhorse of NASA's Space Shuttle fleet, flying far more missions per year than Columbia. Challenger flew on 85 percent of all Space Shuttle missions in 1983 and 1984. Even when the orbiters Discovery and Atlantis joined the fleet, Challenger remained in heavy use with three missions a year from 1983 to 1985.

The Challenger disaster led to a 2-and-a-half year shuttle fleet grounding until 1988, with the launch of space shuttle Discovery on STS-26. Challenger itself was replaced by the Space Shuttle Endeavour, which was first launched in 1992.

The cause of the Challenger disaster was the failure of the pressure seal in the aft field joint of the right Solid Rocket Booster, due to a faulty design unacceptably sensitive to several factors like the effects of temperature, physical dimensions, the character of materials, the effects of reusability, processing and the reaction of the joint to dynamic loading, according to Rogers Commission Report.

Frequently, the Challenger disaster has been used as a case study in the subjects such as engineering safety, the ethics of whistle-blowing, communications, group decision-making, and the dangers of groupthink. It is part of the required readings for engineers seeking a professional license in Canada and other countries.

In addition to the remembrance of Challenger disaster, NASA is remembering Apollo 1 disaster on Jan. 27, 1967. Astronaut Virgil Gus Grissom, first American spacewalker Edward White, and rookie Roger Chaffee were sitting atop the launch pad for a pre-launch test when a fire broke out in their Apollo capsule. The investigation into the fatal accident led to major design and engineering changes, making the Apollo spacecraft safer for the coming journeys to the moon.

NASA is also remembering space shuttle Columbia disaster on Feb. 1, 2003. The seven member crew of the STS-107 mission was just 16 minutes from landing on Feb. 1, when mission control lost contact with the shuttle Columbia. A piece of foam, falling from the external tank during launch, had opened a hole in one of the shuttle's wings, leading to the breakup of the orbiter upon re-entry. The crew members include commander Rick Husband, pilot William McCool, mission specialists Michael Anderson, Ilan Ramon, Kalpana Chawla, David Brown, and Laurel Salton Clark.

During Day of Remembrance of Apollo disaster, NASA Administrator Charles Bolden, Jr. said We honor the Apollo 1, Challenger and Columbia crews, as well as other members of the NASA family who lost their lives supporting NASA’s mission of exploration. We thank them and their families for their extraordinary sacrifices in the service of our nation.

Throughout history, however, we have seen that achieving great things sometimes comes at great cost and we mourn the brave astronauts who made the ultimate sacrifice in support of NASA missions throughout the agency’s storied history. We pause to reflect on the tragic loss of the Apollo 1 crew, those who boarded the space shuttle Challenger in search of a brighter future, and the brave souls who perished on the space shuttle Columbia, U.S. President Barack Obama said.