Update for 12:11 a.m. ET Sept. 29: LSpaceX CEO Elon Musk has teased images of what he calls "Moon Base Alpha" and a "Mars City". Read our initial story. Earlier, Lockheed Martin unveiled a new lander for its Mars Base Camp concept. Full story: Lockheed Martin Unveils Sleek, Reusable Lander for Crewed Mars Missions

Tonight (Sept. 28), SpaceX and Lockheed Martin will unveil their latest plans for getting people to Mars.

Both companies will do so at the 68th International Astronautical Congress (IAC) in Adelaide, Australia. First up is Lockheed, which will announce updates to its "Mars Base Camp" concept at 6 p.m. EDT (2200 GMT; 7:30 a.m. Friday local Adelaide time). You can watch the presentation via Australia's Science Channel.

Then, at 12:30 a.m. EDT Friday (0430 GMT; 2 p.m. Adelaide time), SpaceX founder and CEO Elon Musk will reveal changes to the company's Mars-colonization architecture, which Musk first announced last year at the 67th IAC in Mexico. [SpaceX's Interplanetary Transport for Mars in Images]

"Major improvements & some unexpected applications to be unveiled on Friday at @IAC2017 in Australia," he said via Twitter Monday (Sept. 25).

Artist's illustration of SpaceX's planned Interplanetary Transport System launching a colony ship toward Mars. This artwork is based on the architecture Elon Musk unveiled in September 2016; the SpaceX founder and CEO will reveal an updated version on the night of Sept. 28, 2017. (Image credit: SpaceX)

"Headed to Adelaide soon to describe new BFR planetary colonizer design in detail @IAC2017. This should be worth seeing. Design feels right," Musk added in another tweet Tuesday (Sept. 26). (BFR stands for Big F***ing Rocket.)

SpaceX webcast Musk's talk at last year's IAC live and will do so again for the upcoming presentation at www.spacex.com/webcast. You can also watch Musk's Mars colonization talk live on Space.com here, courtesy of SpaceX.

Lockheed's idea centers on a six-person space station, which company representatives have said could be orbiting the Red Planet by 2028 or so. The astronauts aboard this Mars Base Camp could perform a variety of valuable scientific and exploration work, from operating rovers in near-real time on the surface to scouting out spots for future crewed landings, project team members have said.

"The presentation will include a look at how Mars Base Camp aligns with NASA’s lunar Deep Space Gateway, and a debut of a crewed Mars lander concept," Lockheed representatives said in a media advisory about Thursday's IAC talk.

At last year's IAC meeting, Musk unveiled SpaceX's planned Interplanetary Transport System (ITS), a huge, reusable rocket-spaceship combo designed to help establish a million-person city on Mars in the next 50 to 100 years. The 40-foot-wide (12 meters) booster would feature 42 Raptor engines and be more than twice as powerful as NASA's Saturn V moon rocket. The ITS spaceship, meanwhile, would be capable of carrying a minimum of 100 people to the Red Planet.

Though Musk hasn't revealed what the "major improvements" to this original design might be, there's reason to believe the new iteration may scale things back a bit. In July, a Twitter user asked Musk for hints about the new architecture. "A 9m diameter vehicle fits in our existing factories ... " Musk responded.

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