JPL BLOGS
Inside Views on Outer Space
Hear from scientists, engineers and other experts as they offer a fascinating look at JPL missions, science and history.
JPL | February 24, 2009
Thoughts After Launch
A few hours ago I had the privilege to watch the Orbiting Carbon Observatory launch from Vandenberg Air Force Base. The creativity, effort and dedication of many, many people were sitting on the launch pad. Many of the people who had worked so hard to get the mission to the pad were in attendance with family and friends there to share in the excitement. The weather was perfect. Cold enough to make the stars seems to be just out of reach, still enough to be pleasant to stand outside waiting for the main event. As it got closer, hundreds of voices followed along the magic of the countdown - "10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 - Liftoff!". The rocket cleared the pad - rising on a column of intense white light. At our distance, it seemed to rise forever before the roar finally reached us. In the dark, clear sky we could watch the various stages burn out, fall back and be replaced by the ignition of the next state. Everything seemed to be going perfectly.
We got on the buses to leave the viewing area, excited by what we witnessed and excited by the mission to come. Both feelings did not last long. Soon text messages and phone calls started to disturb the darkened buses. Within a few minutes, it was clear that the launch had not gone as well as we thought. By the time we got off the buses, it looked grim. In the next couple of hours, it became clear that the rocket failed and we never achieved orbit.
Oddly, hearing that the spacecraft hit the ocean near Antarctica made it worse. I had this vision of the system orbiting the Earth - dead and mute - like a modern day Flying Dutchman. Knowing that the hardware I helped design and build had been destroyed on impact made the loss real.
Almost 10 years ago, I was working with a scientist who was also supporting the Mars lander that was lost in 1999. The day after it failed, she told me to always try to enjoy the intellectual challenge of designing a mission and the hardware to make it possible. At the end of the day, that might be all you get. Since then, she has been involved in the incredibly successful Mars Exploration Rovers and the Phoenix lander. She is working to prepare the Mars Science Laboratory for its 2011 launch.
I hope that her past is my prologue. I hope that the next 10 years bring a productive series of missions to advance our understanding of the carbon cycle - much as the recent Mars missions have advanced our understanding of our solar system's history.
TAGS: SOLAR SYSTEM, EARTH, OCO,
JPL | February 20, 2009
Counting Carbon
Imagine if you could scoop exactly one million molecules out of the air in front of you (while being careful not to grab any water vapor). Now, start sorting these molecules into different piles. Start with the two most common molecules and you've sorted 99 percent of your sample -- the nitrogen pile will have about 780,000 molecules, and oxygen pile will have about 210,000 molecules. Working on the third most common molecule, argon, gets you a new pile with about 9,000 molecules. Congratulations, you've sorted 99.9 percent of the molecules into just three piles. The remaining 1,000 molecules are called "trace gases." The most famous and the most common trace gas is carbon dioxide, or CO2. Out of the million you had at the beginning, you'll count about 385 CO2 molecules.
Now, imagine repeating this experiment 12 times per second while flying over Earth at more than 16,000 miles per hour. Each of those counts needs to be accurate enough to note the addition or subtraction of one molecule of CO2 per one million of air. This is the experiment that a group of scientists and engineers at NASA's Jet Propulsion Laboratory conceived almost 10 years ago. We call it the Orbiting Carbon Observatory, and it is now at the launch pad waiting for its ride into space.
The heart of the mission is a very accurate instrument -- called a "spectrometer" -- tuned to sense the presence of CO2. A spectrometer is a type of camera that splits incoming light into hundreds of different colors and then measures the amount of light in each of these colors. In the case of this mission, the spectrometer measures sunlight that has passed through the atmosphere twice: once on the way down to the surface, and then again on the way up to the orbiting spacecraft. When the light passes through air containing CO2, certain colors are absorbed. The spectrometer creates an image with dark bands where the sunlight is partially or completely missing. This image looks similar to a barcode. Encoded in that barcode is the information to infer how many CO2 molecules the sunlight encountered on its way to the spacecraft.
I joined the project in early 2001 as the lead engineer for the spectrometer. In the eight years that have followed, we've gone from an idea to a fully built and tested system sitting on top of a rocket, ready for launch. Along the way, a group of talented people has put in countless hours designing, building, and testing the system. When doing something for the first time, there are always issues that come up -- some of which look insurmountable at the time. It's been a challenge, but the hard work and creativity of our team saw us through all of them.
Now we are waiting for the payoff -- the first data from space. We've done everything we can to be ready. Now, launch awaits ...
TAGS: SOLAR SYSTEM, EARTH, CARBON, OCO, CO2