Human mission to Mars
The farthest humans have been beyond Earth is the Moon, under the U.S. National Aeronautics and Space Administration (NASA) Apollo program which ended in 1972.
[4] Meanwhile, the uncrewed exploration of Mars has been a goal of national space programs for decades, and was first achieved in 1965 with the Mariner 4 flyby.
The energy needed for transfer between planetary orbits, or delta-v, is lowest at intervals fixed by the synodic period.
Shorter Mars mission plans have round-trip flight times of 400 to 450 days,[11] or under 15 months for an opposition-class expedition, but would require significantly higher energy.
[12] In 2014, ballistic capture was proposed, which may reduce fuel cost and provide more flexible launch windows compared to the Hohmann.
[15] Proposed by R. Titus in 1966, it involved a short-stay lander-ascent vehicle that would separate from a "parent" Earth-Mars transfer craft prior to its flyby of Mars.
The Ascent-Descent lander would arrive sooner and either go into orbit around Mars or land, and, depending on the design, offer perhaps 10–30 days before it needed to launch itself back to the main transfer vehicle.
[citation needed] Critics argue that the immense cost outweighs the immediate benefits of establishing a human presence on Mars and that funds could be better redirected toward other programs, such as robotic exploration.
[19] One factor reducing the funding needed to place a human presence on Mars may be space tourism.
As the space tourism market grows and technological developments are made, the cost of sending humans to other planets will likely decrease accordingly.
[20] Several key physical challenges exist for human missions to Mars:[24] Some of these issues were estimated statistically in the HUMEX study.
The allowable limit is 300,000 spores on the exterior of general craft, with stricter requirements for spacecraft bound for "special regions" containing water.
Over the past seven decades, a wide variety of mission architectures have been proposed or studied for human spaceflights to Mars.
These have included chemical, nuclear, and electric propulsion, as well as a wide variety of landing, living, and return methodologies.A number of nations and organizations have long-term intentions to send humans to Mars.
[59] NASA is carrying out research on retropropulsive deceleration technologies to develop new approaches to Mars atmospheric entry.
[61] One of the medical supplies that might be needed is a considerable mass of intravenous fluid, which is mainly water, but contains other substances so it can be added directly to the human blood stream.
The most recent mathematical models predict 33% of astronauts will be at risk for osteoporosis during a human mission to Mars.
[67] In 2022, NASA co-funded a multi-year grant of US$1.9 million awarded to Arizona State University, the University of Arizona, and the Florida Institute of Technology to explore the idea of using Dehalococcoides mccartyi bacteria, among other microbes, to reduce the perchlorate content and add organic material to simulated Mars regolith.
[68] D. mccartyi also break down the perchlorates into harmless chloride and useful oxygen along with leaving organics in the soil as excretions and when they die,[68] thus potentially solving several problems at one time.
[73] In 2008, the ESA called a sample return "essential" and said it could bridge the gap between robotic and human missions to Mars.
[78] The rover Perseverance, which landed on Mars in 2021, is equipped with a device that allows it to collect rock samples to be returned at a later date by another mission.
[80] Starting in 2004, NASA scientists have proposed to explore Mars via telepresence from human astronauts in orbit.
