Arno Wielders

Mars One funding came from astronaut application fees, donations, undisclosed private investment, intellectual property (IP) rights, and mostly, the potential sale of future broadcasting rights. Over three-quarters of the funds reportedly went to concept design studies. Mars One states that "income from donations and merchandise have not been used to pay salaries". To date, no financial records have been released for public viewing. Mars One initially estimated a one-way trip, excluding the cost of maintaining four astronauts on Mars until they die, at US$6 billion. Lansdorp has declined questions regarding the cost estimate.

Reality TV

A proposed global reality-TV show was intended to provide funds to finance the expedition. However, no such television show emerged and no contracts were signed. The astronaut selection process (with some public participation) was to be televised and continue through the first years of living on Mars.

Discussions between Endemol started in June 2014, producers of the Big Brother series, and Mars One ended with Endemol subsidiary Darlow Smithson Productions issuing a statement in February 2015 that they "were unable to reach agreement on the details of the contract" and that the company was "no longer involved in the project." Lansdorp updated plans to no longer include live broadcasts, but instead would rely on documentary-style short films produced by the company Stateless Media.

Donations and merchandise

Since the official announcement of their conversion to a Stichting foundation, Mars One began accepting donations through their website. As of 4 July 2016, Mars One had received $928,888 in donations and merchandise sales. The 2016 donation update added the Indiegogo campaign ($313,744) to the private donation and merchandise total.

Mars One received a variety of criticism, mostly relating to medical, technical and financial feasibility. There were also unverified claims that Mars One was a scam designed to take as much money as possible from donors, including reality show contestants. Many criticized the project's US$6 billion budget as being too low to successfully transport humans to Mars, to the point of being delusional. A similar project study by NASA estimated the cost of such a feat at US$100 billion, although that included transporting the astronauts back to Earth. Objections had also been raised regarding the reality TV project associated with the expedition. Given the transient nature of most reality TV ventures, many believed that as viewership declined, funding could significantly decrease, thereby harming the entire expedition. Further, contestants reported that they were ranked based on their donations and funds raised.

Academia

John Logsdon, a space policy expert at George Washington University, criticized the program, saying it appeared to be a scam and not "a credible proposition".

Chris Welch, director of the Masters Programs at the International Space University, said "Even ignoring the potential mismatch between the project income and its costs and questions about its longer-term viability, the Mars One proposal does not demonstrate a sufficiently deep understanding of the problems to give real confidence that the project would be able to meet its very ambitious schedule."

Gerard 't Hooft, theoretical physicist and Mars One ambassador, has stated that he thought both their proposed schedule and budget were off by a factor of ten. He said he still supported the project's overall goals.

A space logistics analysis conducted by PhD candidates at the Massachusetts Institute of Technology (MIT) revealed that the most optimistic of scenarios would require 15 Falcon Heavy launches that would cost approximately $4.5 billion. They concluded that the reliability of Environmental Control and Life Support systems (ECLS), the Technology Readiness Levels (TRL), and in situ resource utilization (ISRU) would have to be improved. Additionally, they determined that if the costs of launch were also lowered dramatically, together this would help to reduce the mass and cost of Mars settlement architecture. The environmental system would result in failure to be able to support human life in 68 days if fire safety standards on over-oxygenation were followed, due to excessive use of nitrogen supplies that would not then be able to be used to compensate for leakage of air out of the habitat, leading to a resultant loss in pressurization, ending with pressures too low to support human life. Lansdorp replied that although he has not read all the research, supplier Lockheed Martin said that the technologies were viable.

Another serious concern uncovered in the research conducted by MIT was replacement parts. MIT PhD candidates estimated the need for spare parts in a Mars colony based on the failure rates of parts on the International Space Station. They determined that a resupply mission every two years would be necessary unless a large space in the initial launch were to be reserved for extra materials. Lansdorp commented on this saying, "They are correct. The major challenge of Mars One is keeping everything up and running. We don't believe what we have designed is the best solution. It's a good solution."

In March 2015, one of the Mars One finalists, Joseph Roche, stated to media outlets that he believed the mission to be a scam. Roche holds doctorate degrees in physics and astrophysics, and shared many of his concerns and criticisms of the mission. These claims include that the organization lied about the number of applicants, stating that 200,000 individuals applied versus Roche's claim of 2,761, and that many of the applicants had paid to be put on the list. Furthermore, Roche claimed that Mars One was asking finalists for donations from any money earned from guest appearances (which would amount to a minimal portion of the estimated $6 billion required for the mission). Finally, despite being one of 100 finalists, Roche himself never spoke to any Mars One employee or representative in person, and instead of psychological or psychometric testing as is normal for astronaut candidates (especially for a lengthy, one-way mission), his interview process consisted of a 10-minute Skype conversation.