NASA announced recently its intended design for a heavy-lift rocket that will to carry astronauts to Mars, appeasing lawmakers irked by a delay in the plan’s unveiling.

The new rocket, called the Space Launch System, will work with a crew capsule based on the Orion spacecraft Lockheed Martin [LMT] had developed for former President George W. Bush’s now-defunct Constellation program, which aimed to return astronauts to the moon.

The announcement about the heavy-lift rocket advances President Barack Obama’s reworked manned-spaceflight program, which has a long-term goal of sending astronauts to Mars and invests in a nascent commercial spaceflight industry for travel to low-Earth orbit.

“Having settled on a new and powerful heavy-lift launch architecture, NASA can now move ahead with building that rocket and the next-generation vehicles and technologies needed for an ambitious program of crewed missions in deep space,” John Holdren, assistant to the president for science and technology, said in a statement.

The decision about the rocket follows months of review of potential designs.

NASA said the rocket will use a liquid hydrogen and liquid oxygen fuel system, with RS-25D/E engines providing the core propulsion and the J2X engine used in the upper stage.

The space agency said it plans to hold an industry competition for develop the boosters “based on performance requirements” and not on the type of proprellant.

“The decision to go with the same fuel system for the core and the upper stage was based on a NASA analysis demonstrating that use of common components can reduce costs and increase flexibility,” NASA said in a statement. The agency plans for the rocket to lift 70 to 100 metric tons in early flights before evolving to have a lift capacity of 130 metric tons.

The agency said the specific acquisition strategy for procuring the rocket’s core, booster, and upper stages “is being developed” and will be announced in the future. Lawmakers who had prodded NASA to move forward with the heavy-lift rocket–including Sens. Bill Nelson (D-Fla.) and Kay Bailey Hutchison (R-Texas)–applauded the announcement.

“This is perhaps the biggest thing for space exploration in decades,” Nelson said, when he joined Hutchison and NASA Administrator Charles Bolden in announcing the new rocket design plans. The senators had been frustrated with a months’ long delay in the rocket-design decision.

“The approval of the final design of the rocket signals that the White House has confidence in the technology, as well as faith in the budget numbers provided by NASA,” Nelson’s office said in a statement.

The NASA Authorization Act Obama signed into law last year calls for NASA to be ready for an initial launch of the heavy-lift rocket and capsule by 2017.