Since a malfunction five years ago put the mission on hiatus, NASA's Orbiting Carbon Observatory-2 is gearing up for its second launch attempt Tuesday from the California coast, hopefully becoming the first successful spacecraft to measure and monitor harmful greenhouse gas levels.

The two-year, $465 million project, known as OCO-2, will be able to measure and map carbon dioxide (CO2) levels in the atmosphere, and give scientists a better understanding of how the Earth's oceans, soils and forests absorb CO2.

"We really don't have a lot of data right now to understand the uptake of carbon by these terrestrial ecosystems," OCO-2 science team member Paul Wennberg, a professor of atmospheric chemistry at the California Institute of Technology, told the Los Angeles Times.

According to NASA, humans release nearly 40 billion tons of CO2 into the atmosphere annually via industrial activities, such as the burning of fossil fuels. Though, this number varies from year to year. CO2 is a greenhouse gas that traps heat from the Sun that would otherwise be released into space, and as a result are increasing the Earth's average surface temperature.

OCO-2, which is scheduled to launch at 2:56 a.m. PDT on Tuesday at Vandenberg Air Force Base in California, will measure atmospheric CO2 by looking at the colors, or wavelengths, of sunlight that the gas absorbs using spectrometers. The satellite will collect about 24 measurements every second, or a million measurements every day.

"The data we will provide will help our decision-makers at both the local and federal levels be better-equipped to understand carbon dioxide's role in climate change because (the observatory) will be measuring this greenhouse globally," said Betsy Edwards, program executive at NASA Headquarters in Washington, Reuters reported.

This is not the first time NASA is trying to launch OCO. In 2009, an earlier version failed to separate from its launch vehicle - an Orbital Taurus XL rocket - and burned up on reentry, costing the agency about $209 million.