Journey to Cosmos' Dark Heart
When scientists encounter a mystery, it is in their nature to seek out an answer. Dark energy is one of the biggest mysteries that modern-day astronomers have faced, so they want to study it further. Agencies that run missions and telescopes, like NASA and the Department of Energy, respond by allocating funds to develop new technologies and to refine old technologies to study the mystery.
The first hints of dark energy came with observations of supernovae billions of light-years from Earth. One way to continue studying dark energy is to observe a larger number of supernovae across the Universe. That is the plan of JDEM, though the exact details of the mission have not yet been determined.
Process from mystery to mission
This article can be used to illustrate the process that NASA goes through to develop a mission. Long before a satellite is launched, a NASA mission begins with a question that astronomers want to answer. Some questions that have driven NASA missions include, "What powers a gamma-ray burst?" (Swift), "How is the cosmic microwave background distributed across the sky?" (COBE and WMAP), and "What is the nature of dark energy?" (JDEM). With a question in hand, astronomers determine the types of information they need to begin to answer the question. In response, NASA solicits the astronomical community to submit mission concept ideas. Teams of astronomers and engineers write proposals for telescopes and instruments that they believe will provide the information necessary to answer the question. These proposals have to demonstrate how each proposed mission concept would answer the question, and why a particular method might be better than others.
Using a mission concept, or a combination of mission concepts, NASA then develops a mission plan. NASA invites its own teams, teams from University laboratories, other government agencies, and industry (i.e. companies outside of the government and Universities) to write proposals to build the telescopes, instruments and spacecraft based on the mission plan. The teams that participate in the mission are chosen from this competitive process based on the team with the best combination of qualifications and skills to get the job done with a given budget.
Usually, construction of the flight instruments, telescopes, and spacecraft doesn't take place until years after the initial question was posed. Once construction starts, it can take another several years to complete. Each group is responsible for testing their own contributions to the final spacecraft, but NASA will also test the spacecraft once it is assembled into a complete mission. Only then will it be launched into space.
The process from a question to the launch of a mission can take 10 years or more (usually more). As of late 2008, JDEM is still in the mission-planning phase. If all goes as planned, JDEM may launch in a decade, with its first science results returned a year or so later.
The following webpages have more detailed information: