Humans are simply determined to visit Mars, some via the more traditional route of studying hard, puking one’s guts out in a human centrifuge and becoming an astronaut, while others as winners of what amounts to a reality show in outer space. But after sorting out all of the PR and funding issues, one of the challenges involved in getting to Mars is actually landing a spacecraft heavy enough to haul all the iPhones, yoga mats, astronaut ice cream sandwiches, video games, and other crucial equipment that a visit by humans – or maybe even a permanent settlement – would require.
JPL, LDSD and Reddit AMA
On May 12th, NASA scientists Ian Clark and Mark Adler from the Jet Propulsion Laboratory (JPL) hosted an “Ask Me Anything” on Reddit to answer users’ questions about one of NASA’s current projects that hopes to tackle that very problem. Since last year, JPL has been testing the Low-Density Supersonic Decelerator (LDSD), a landing system scientists hope will facilitate a human trip to Mars in the near future. The LDSD builds off of the success of NASA’s Viking program, which brought two landers safely through Mars’ thin atmosphere and onto the Martian surface in 1976. Unfortunately, the deceleration and landing technology on Viking is only suited to payloads of a ton or two, so newer technology will have to decelerate much heavier spacecraft as they enter Mars’ low-density atmosphere:
The new designs borrow from the same technique used by the Hawaiian pufferfish—the ‘o‘opu hue—to increase its size without adding mass: rapid inflation.
These systems, called low density supersonic decelerators, aim to solve the complicated problem of slowing Martian entry vehicles down enough to safely deliver large payloads to the Martian surface without bringing along massive amounts of extra rocket propellant or carrying a large and heavy atmospheric entry shield.
The LDSD team tested the system, which includes supersonic inflatable devices and gigantic supersonic parachutes, high above Hawaii in June 2014, and on May 12th, users got to ask Clark and Adler about the latest test’s success. Users also got a chance to find out how the team plans to manage the fuel supply and just how much tonnage the LDSD could support, among other questions. The following video features the LDSD team’s test from last June.
“Considering that the Mars mission is not a one way ticket, how will the fuel be enough for the return as well?” asked one user. Clark replied that NASA had the interesting idea of “(distilling) propellant from the Martian atmosphere. For example, distilling liquid oxygen from the carbon dioxide atmosphere.”
Another user asked what the team learned from the first test in June 2014. While Clark observed enthusiastically that the test was a success, he said that there were “a gajillion things that have to happen just right.” When one user asked why the parachute in the first test had torn, Adler answered that “asymmetric inflation and pressure in the crown tore the disk of fabric at the top…this time we got rid of the disk and have Kevlar structure in the crown for strength.”
The LDSD team is preparing for another test of the system next month, and Clark and Adler are inviting users to observe the event on JPL’s Ustream page. Be sure to check out the Reddit AMA for more user fielded questions and commentary from Clark and Adler. And if you prefer something more straight forward, then peruse this concise, easy-to-read NASA fact sheet on the LDSD.