These Questions originally appeared on Quora - the knowledge sharing network where compelling questions are answered by people with unique insights.
Answers by Robert Frost, Instructor and Flight Controller at NASA, on Quora.
A: I am not aware of any evidence of life on other planets. I think there is, however, starting to be more and more evidence that the conditions to support life have existed and maybe do still exist, at locations other than Earth.
The entire subject is challenging because we have to start by defining a term on which we have a very narrow perspective. What is Life? If life is something that can reproduce, is a mule alive? If life is something that can grow, is a crystal alive? And if we come to a consensus on what makes something "life", does that mean all objects with those characteristics will be recognizably similar to each other?
All we really know about life is based upon observations of the life that formed on the planet Earth. From those observations, we conclude that life involves carbon and life requires water. So, we extrapolate that if we can find places where water and complex carbon based molecules exist, then life may also exist. That may well be short-sighted There may be life that doesn't need water nor carbon.
But, chemistry tells us that life is more likely to be based on carbon than on any other element. Carbon is the lightest, most abundant, element with four valence electrons in a shell capable of eight. That means a carbon atom can form four covalent bonds while nitrogen (to its right) can form three and oxygen (to nitrogen's right) can form two. Carbon can also form double bonds, allowing strong (but not so strong the molecules can't change), complex, branching molecules. This means carbon is a light and abundant element capable of forming very complex and flexible molecules. Life is complex. Life needs to be flexible to survive.
Water is also viewed as a near prerequisite for life. Water is a universal solvent. It can dissolve many substances, making it extremely valuable at transporting materials in and out of living cells.
So, we look for complex carbon molecules and we look for water and we look for temperatures at which that water can be a fluid.
Just three months ago, NASA announced that flowing water had been observed on Mars. Researchers studying imagery from the Mars Reconnaissance Orbiter observed grooves formed by the transport of salts via water.
Four months before that, other researchers published a paper on late-stage formation of Martian chloride salts that posited that in the area they studied, a lake existed on Mars 3.6 billion years ago. At that same time, the Archaen eon, it is believed that prokaryotes were evolving on Earth.
And four months before that, another group of researchers published a paper that, based on studying atmospheric water of Mars and deuterated forms, concluded that early in its life (around 4 billion years ago) Mars had a global equivalent water layer at least 137 meters deep.
If Mars had liquid water for hundreds of millions of years, it could certainly be possible that life, if even just for a geologically brief period, did appear on Mars.
NASA missions like Cassini and Dawn are doing more than just sending us amazing images of the bodies in our solar system. They are provide data that indicates how prevalent water is in the solar system. It is believed that both Ganymede and Callisto (moons of Jupiter) and Enceladus, Titan, and Mimas (moons of Saturn) have underground saltwater oceans. Neptune's moon Tritan might also have a subsurface ocean. Just a few months ago, New Horizons sent back images showing frozen water on Pluto.
In September, a paper was published in the journal Icarus, about shock experiments done to examine the potential role that cometary impacts may have played in the evolution of life. Not only could comets have provided much of the water on the terrestrial planets, but the paper suggests that comet impacts played a role in chemical evolution via supplying linear peptides
The search for exoplanets is also revealing evidence that Earth is not so unique. So far, more than thirty potentially habitable exoplanets have been found in other solar systems.
There's a lot of optimism. Recently, NASA chief scientist, Dr. Stofan said:
"I think we're going to have strong indications of life beyond Earth within a decade, um and I think we're going to have definitive evidence within 20 to 30 years. We know where to look, we know how to look, in most cases we have the technology, and we are on the path to implement it."
A: A flight controller is a member of the operations team. They operate the vehicle.
The Flight Operations Directorate (FOD) divides its responsibilities into three phases: Plan, Train, and Fly (P-T-F). That means we plan for a mission, we train for a mission, and then we fly the mission.
A flight controller is assigned to a discipline. A discipline might be based on a system of the vehicle or on a function of the mission.
Planning for a mission can begin a couple of years in advance. Flight controllers are responsible for all of the operations products (procedures, flight rules, displays etc.).
Flight controllers attend various meetings such as TIMs (Technical Interchange Meetings), SRPs (Safety Review Panels) JOPs (Joint Operations Panels) and gather information about the mission. In parallel they work to prepare the operations products. A small change in the software, hardware, or operations concept can have significant ripple effects through the operations products.
Much of a flight controller's job is paperwork and the integration and coordination that go along with that paperwork. Let's go through a small example. A visiting vehicle provider made changes to one of the radios used in their spacecraft. That resulted in the Avionics Systems Analysis/Engineering group revising their report on the potential for radio interference for various combinations of communication systems. That report was a reference for a flight rule I owned called HTV/ATV/DRAGON/CYGNUS S-BAND COMMUNICATIONS CONSTRAINTS. As owner of that flight rule, I had to meet with the radio-frequency engineers and acquire an understanding of the changes and impacts. I then had to revise the flight rule so that we would have proper guidance to follow during multiple vehicle operations. Each flight rule can have many stakeholders. Before publishing the updated rule, I had to coordinate my suggested changes with each of those stakeholders. For a program like the International Space Station (ISS), that means people all over the world. Sometimes those stakeholders see things a little differently and will suggest alternative changes. The flight controller has to negotiate and get everyone onto the same page. This is done against a ticking clock as the next FRCB (Flight Rule Change Board) approaches. That's the meeting, led by a Flight Director, where flight controllers present their flight rule changes. If accepted at that meeting, they will be incorporated into the next publication of the rules. It's important to get that done before the next mission that will be affected by the rule.
Software testing is also a big part of this phase. There is a lot of software in a program like the ISS.; The Command and Control MDMs (multiplexer-demultiplexer), the Internal MDMs, the External MDMs, the PCS (laptop), the Operations LAN (Local Area Network) and so on and so on, each have their update cycles. Flight controllers are responsible for keeping up with these changes and performing both new feature and regression testing. These changes might require changes in displays, telemetry libraries, and procedures.
Flight controllers are regularly in training and providing training. Missions will have flight specific simulations in which the team will run through complicated portions of the mission timelines. In order to work a mission, flight controllers must be certified, current, and proficient in their system.
The most experienced flight controllers in each system are also instructors. They train the new flight controllers and also provide much of the training for the astronauts. That means they build training, conduct training, and evaluate training. They also operate the big simulators we use for integrated training.
Once all of the planning is complete and everyone is fully trained, it's time to fly the mission. For flight controllers, this is called sitting console. Some of the flight controllers are in the FCR (Flight Control Room) that is often shown on NASA TV. Some are in other rooms around the FCR, such as the MPSR (Multi-purpose Support Room). For complex operations, a discipline might have two flight controllers on console. The one in the FCR is called the "front room flight controller" and the one in the MPSR is called the "back room flight controller".
The console is a large desk with multiple monitors and computers. The flight controller uses those monitors to monitor the telemetry from their discipline.
Different control teams handle commanding in different ways. It's quite common to have a single person in the room send all of the commands to the vehicle. ISS is too large and too complicated for that to be possible, so the ISS flight control team was designed with each discipline having command capability.
Dealing with system failures
A flight controller is constantly monitoring telemetry that is downlinked from the vehicle. Should that telemetry indicate a problem, or should the crew call down to announce a problem, it is the flight controller's responsibility to quickly provide an FIW (Failure Impact Workaround) call to the flight director. That means they have to quickly assess their telemetry and determine what the failure was, what the impact of the failure is or will be and what plan they can offer up to workaround the failure to ensure continued functionality of their system. The immediate goal is to safe the system. Once the system is saved, the flight controller can begin troubleshooting to figure out what really happened and developing a long term plan to repair or replace the failed items.
These questions originally appeared on Quora. - the knowledge sharing network where compelling questions are answered by people with unique insights. You can follow Quora on Twitter, Facebook, and Google+. More questions: