An independent review of NASA's ambitious mission to return about half a kilogram of rocks and soil from the surface of Mars has found that the program is unworkable in its current form.

NASA had been planning to launch the critical elements of its Mars Sample Return mission, or MSR, as soon as 2028, with a total budget for the program of $4.4 billion.

The independent review board's report, which was released publicly on Thursday, concludes that both this timeline and budget are wildly unrealistic.

The findings of the independent review, led by Orlando Figueroa, a retired deputy center director for science and technology at NASA’s Goddard Space Flight Center, echo a report published by Ars Technica about three months ago raising serious questions about costs and schedule.

After the Ars Technica report, some policymakers in the US Senate also expressed serious concerns about the direction of the sample return program.

This vehicle would carry the samples back to Earth orbit, where they would be released into a small spacecraft to land on the planet about five years after the mission's start.

Saved 60% of original text.