NASA's Greenhouse Gas Observatory Captures 'First Light'

mdsolar (1045926) writes with news that NASA's second attempt to launch a satellite to map carbon dioxide levels across the globe succeeded, and its instruments are operating properly. From the article: NASA's first spacecraft dedicated to studying Earth's atmospheric climate changing carbon dioxide levels and its carbon cycle has reached its final observing orbit and taken its first science measurements as the leader of the world's first constellation of Earth science satellites known as the International 'A-Train. The Orbiting Carbon Observatory-2 (OCO-2) is a research satellite tasked with collecting the first global measurements of atmospheric carbon dioxide (CO2) — the leading human-produced greenhouse gas and the principal human-produced driver of climate change. The 'first light' measurements were conducted on Aug. 6 as the observatory flew over central Papua New Guinea and confirmed the health of the science instrument.

Re:fast forward 5 years....

[bunratty]

I don't think it's climatologists who are the ones dismissing results they don't want. Actually, everyone would love to see that carbon dioxide emissions cause very little warming, but that's just not what the bulk of the data shows [wordpress.com].

Re:let me help cuz I apparently am a slashdot edit

[Anonymous Coward]

First light is significantly more than bootup. After launch, typically at least a few days to weeks are spent doing initial power-on and checkout of various subsystems before collecting science or mission data. The initial health checks (monitoring component temperatures, voltages, currents, communications, powering on subsystems in order, etc) are much more analogous to booting up.

Once initial checks are complete, then the instrument is commanded to collect real data. That is first light. For any satellite like this which is years in the making, first light is most definitely a "cool" milestone.

Source: I work on (unrelated to this) remote sensing satellite systems and have supported at least 8 launches / early orbit testing phases over the years.

Re:How is CO2 leading cause of warming?

[gstoddart]

If CO2 were a leading cause of warming, why would the temperatures not be spiking along with CO2 levels?

You seem to be assuming it's linear and immediate, as opposed to being a complex system with built in lag and other factors -- which would boil down to "if I release X amount of CO2, tomorrow the temperature will go up by Y".

It doesn't work that way, and is much more complex.

Much like if you turn up your thermostat, your house isn't instantly warmer, because, thermodynamics.

commissioning & Phase E

[oneiros27]

The launch of the spacecraft is effectively the start of 'Phase E' (operations) for the instruments ... but there's a lot of things that still have to happen:

• They have to deploy any solar panels (unless it's got an RTG), and align with the sun
• They have to check out the spacecraft health, to make sure that nothing shook loose during launch, and they can talk to it.
• The spacecraft has to get to the right place. (which takes *years* for missions to the outer planets)
• They test the instruments against a known source (calibration lamp or similar)
• They deploy antenna or instrument booms, remove covers, etc.
• They take real measurements (aka. "first light")
• They may perform maneuvers (eg, take an image, roll the spacecraft over, take an image again ... or take an exposure whole rolling) for flat fielding (aka. "calibration")
• They compare the results from the new sensor against other measurements to determine how (aka. "validation")

They refer to this whole period as "commissioning". They're not always run in order (eg, for the missions to the outer planets, which might take *years* to get to, they try to check on the health of the instruments before they get to the planet). For some instruments, it might take years to validate the data.

There's also typically a press conference with the "first release" of the data, after the first calibration is done, but that's more to do with scientists on the ground than the spacecraft itself.

disclaimer : I work for a NASA center, but I don't deal with spacecraft directly; I just manage the data after it's downlinked & processed.