http://www.space.com/36270-nasa-deep-space-gateway-moon-orbit.html
It looks like NASA's stepping-stone to Mars will be a miniature space station in lunar orbit rather than a chunk of captured asteroid.
The agency plans to build an astronaut-tended "deep space gateway" in orbit around the moon during the first few missions of the Space Launch System (SLS) megarocket and Orion crew capsule, which are scheduled to fly together for the first time in late 2018, NASA officials said.
"I envision different partners, both international and commercial, contributing to the gateway and using it in a variety of ways with a system that can move to different orbits to enable a variety of missions," William Gerstenmaier, associate administrator for Human Exploration and Operations at NASA headquarters in Washington, D.C, said in a statement. [Red Planet or Bust: 5 Crewed Mars Mission Ideas]
"The gateway could move to support robotic or partner missions to the surface of the moon, or to a high lunar orbit to support missions departing from the gateway to other destinations in the solar system," Gerstenmaier added.
One of those "other destinations" is Mars. NASA is working to get astronauts to the vicinity of the Red Planet sometime in the 2030s, as directed by former President Barack Obama in 2010. For the last few years, the agency's envisioned "Journey to Mars" campaign has included the Asteroid Redirect Mission (ARM), an effort to pluck a boulder from a near-Earth asteroid and drag the rock to lunar orbit, where it could be visited by astronauts aboard Orion.
But ARM's future looks bleak; President Donald Trump provided no money for the mission in his proposed 2018 federal budget, which the White House released earlier this month.
Also see:
https://www.nasa.gov/feature/deep-space-gateway-to-open-opportunities-for-distant-destinations
http://www.popularmechanics.com/space/a25872/nasa-cis-lunar-orbit/
https://www.nasa.gov/mission_pages/tdm/sep/index.html
(Score: 3, Interesting) by DannyB on Monday April 17 2017, @06:09PM (1 child)
If you fall off an earth based space elevator wouldn't a parachute be enough? Don't you only need a heat shield if you have the hypersonic velocity of being in orbit? A space elevator is just a very tall tower. You fall straight down.
If you fall off a lunar elevator, I wonder how practical it would be to have a small landing jet since the lunar gravity is only 1/6 the Earth's?
Poverty exists not because we cannot feed the poor, but because we cannot satisfy the rich.
(Score: 0) by Anonymous Coward on Monday April 17 2017, @06:51PM
No, on a space elevator you have a lateral velocity varying linearly with altitude, from 0.5km/s at the surface (0 relative to the surface) to 3.1 km/s at GEO (2.6 km/s relative to the surface). Of course, if you "fall off" from a point near GEO, you'll enter an elliptical orbit with a perigee well clear of Earth, so the worst case (wikipedia says around 23000km) is when the resulting orbit just grazes Earth at perigee; the velocity at perigee would be about 10km/s.