A flying saucer-shaped test vehicle designed to allow heavy payloads to be landed on Mars will take to the skies this evening.
Future robotic and human missions to Mars will require larger and heavier spacecraft so the US space agency has designed the Low Density Supersonic Decelerator (LDSD) to test new technologies that use atmospheric drag to slow vehicles as they enter the Martian atmosphere, including a super-sonic parachute and a 6m supersonic inflatable aerodynamic decelerator (SIAD-R).
The first launch opportunity for the test vehicles maiden flight will be at 8.30am local time today (7.30pm GMT) at the US Navy's Pacific Missile Range Facility in Kauai, Hawaii, with Nasa engineers hoping to find out how the craft performs in near-space and at high Mach speeds.
"After years of imagination, engineering and hard work, we soon will get to see our Keiki o ka honua, our 'boy from Earth,' show us its stuff," said Mark Adler, project manager for the Low Density Supersonic Decelerator at Nasa’s Jet Propulsion Laboratory (JPL) in Pasadena, California.
"The success of this experimental test flight will be measured by the success of the test vehicle to launch and fly its flight profile as advertised. If our flying saucer hits its speed and altitude targets, it will be a great day."
To reach its test speed and altitude the saucer will be taken to 120,000ft by a gigantic helium balloon. Once there four small rocket motors will fire to spin up and gyroscopically stabilize the saucer before a Star 48B long-nozzle, solid-fuelled rocket engine kicks in with 17,500 pounds of thrust, sending the test vehicle to the edge of the stratosphere.
"Our goal is to get to an altitude and velocity which simulates the kind of environment one of our vehicles would encounter when it would fly in the Martian atmosphere," said Ian Clark, principal investigator of the LDSD project at JPL.
"We top out at about 180,000 feet and Mach 4. Then, as we slow down to Mach 3.8, we deploy the first of two new atmospheric braking systems."
The two braking technologies are not due to be tested until two test flights next year, but the project management team decided to fly them anyway as if the test vehicle flies as expected the team could get a treasure-trove of data on how they perform a full year ahead of schedule.
The SIAD-R, essentially an inflatable doughnut that increases the vehicle's size and therefore its drag, is deployed at about Mach 3.8 and will quickly slow the vehicle to Mach 2.5 where the parachute, the largest supersonic parachute ever flown, first hits the supersonic flow.
About 45 minutes later, the saucer is expected to make a controlled landing onto the Pacific Ocean off Hawaii.