Dec 16, 2017 -

From our Expert Voices conversation on travel to Mars.

To make a Mars mission a reality, we will lean on four main capabilities:

  1. Controlled hypersonic flight of slender-body vehicles. SpaceX has successfully brought back the first stage of their Falcon 9 rockets, testing on both a droneship at sea and a landing pad near their launch site.
  2. Supersonic retro-propulsion. For large objects, parachutes and other familiar landing systems won't work on the Martian surface. We'll need a new landing propulsion in which a rocket engine descending at supersonic speeds is ignited in order to slow down for landing.
  3. Full and rapid reusability of rockets and spacecraft. Aircraft-like operations will be essential in keeping down costs.
  4. Refueling in orbit and on planetary surfaces. We'll need to "live off the land" as much as possible. That means, for example, turning Mars' atmosphere into rocket fuel and launching fuel tankers into space to refuel a primary ship.

SpaceX has already demonstrated the first and second of these capabilities and efforts on the third are progressing. The refueling challenges are trickiest—they will require complicated on-orbit and on-surface operations that involve engineering and procedures yet to be developed.

What's next: While the timeline and capabilities are certainly ambitious, the U.S. aerospace industry has demonstrated it is ready to lead us into this exciting future.

Other voices in the conversation:

What's next

Bolton alleges in book that Trump tied Ukraine aid to investigations

Photo: Alex Wong/Getty Images

President Trump's former national security adviser John Bolton alleges in his forthcoming book that the president explicitly told him "he wanted to continue freezing $391 million in security assistance to Ukraine until officials there helped with investigations into Democrats including the Bidens," the New York Times first reported.

Why this matters: The revelations present a dramatic 11th hour turn in Trump's Senate impeachment trial. They directly contradict Trump's claim that he never tied the hold-up of Ukrainian aid to his demands for investigations into his political opponent Joe Biden.

Honoring Kobe Bryant: Sports stars, politicians and celebrities mourn NBA great

Kobe Bryant on court for the Los Angeles Lakers during the Sprite Slam Dunk Contest on All-Star Saturday Night, part of 2010 NBA All-Star Weekend at American Airlines Center in Dallas in February 2010. Photo: Jed Jacobsohn/Getty Images

Sports stars, politicians and celebrities paid tribute to NBA legend Kobe Bryant, who was killed in a California helicopter crash alongside his 13-year-old daughter, Gianna, and seven others on Saturday. He was 41.

What they're saying: Lakers great Shaquille O'Neal said in an Instagram post of his former teammate, "There's no words to express the pain I'm going through now with this tragic and sad moment of losing my friend, my brother, my partner in winning championships, my dude and my homie. I love you brother and you will be missed."

Go deeperArrow3 hours ago - Sports

What's next: Trump's broader travel ban

A sign for International Arrivals is shown at the Seattle-Tacoma International Airport. Photo: Ted S. Warren/AP

President Trump is expected to announce an expanded travel ban this week, which would restrict immigration from seven additional countries — Nigeria, Myanmar, Sudan, Belarus, Eritrea, Kyrgyzstan and Tanzania, per multiple reports.

  • The announcement would come on the third anniversary of Trump's original travel ban, which targeted Muslim-majority nations, per Axios' Stef Kight.