Friday, January 21, 2011

Milestones Met

NASA HQ set a series of engineering milestones before the SIM Team in 2000.  Those milestones were met, or exceeded in each case.    

    Each of these milestones was designed to "prove" that SIM would be able to actually chart stars with an unprecedented accuracy.  That precision is the key to achieving SIM's multiple goals, including the detection of Terrestrial ExoPlanets.

   The 1st Four Milestones were to be met before SIM would be allowed to proceed to Phase B in 2003.  The SIM team successfully achieved that.  By 2005, the SIM project had checked off all of the 8 milestones set before it.  Since 2005, the team worked on reducing engineering risk further.

   What we are faced with, in these times of extreme budget pressures is a choice of whether NASA should, once more, walk away from a partially complete program.

Thursday, January 20, 2011

Contact with Destiny

     We are on the threshold of a new era.  With SIM, we will have the capability, for the first time in history, to find New Worlds in our stellar neighborhood.  By New Worlds, I mean planets such as our Earth, planets of the right size, and orbiting their parent stars at the right distance.  

     The urgency of continuing the SIM project is best expressed in the words of the late Carl Sagan in his book, Contact.  On page 36, the protagonist of the novel, Dr. Arroway, is arguing the case for SETI, the Search for ExtraTerrestrial Intelligence.  Those words, I believe, apply equally to SIM.  Here is the relevant quote  -

  "This is the time to be optimistic.  If we lived in any previous time of human history, we could wonder about this all our lives, and we couldn't do a thing to find the answer.  But this time is unique. ....Wouldn't you be ashamed of your civilization if we were able to listen and didn't have the gumption to do it?"  

    SIM will not listen.  Rather, it will look.  However, the message is the same.  This is a special time in which we now live.  As a species, we are poised to find, and map, nearby Earths.  This is not the time to pause, to turn our backs on the challenge that we face.  With the data from SIM, we will be able to answer the question of whether there are Worlds, like our own, circling the nearest stars.  As Sagan wrote in Contact,       

      "Can you think of a more important question?"  

Saturday, January 8, 2011

Insight Through Precision

    The SIM Interferometer observatory will be a highly capable tool not only for the discovery of Exoplanets. Because of its ability to locate stars with stunning precision, SIM will also revolutionize several fields of Astrophysics.  Those of you who are amateur astronomers may not realize that the properties of Main Sequence stars are not fully understood.  One of the main reasons for this is the lack of data concerning stars' Masses and Distances.  SIM will change all of that.
     The SIM project has put out a book titled, "SIM Lite Astrometric Observatory."  It goes into detail on the science and technology of the SIM space observatory.  Here is a link to Chapter 8, which discusses the contributions of SIM to our basic knowledge of how stars work.

Stellar Maps

   To pick one of the target areas that will benefit from SIM, let's consider O and B giant stars.  For the first time, with SIM's data, we will be able to know the distances to a statistically significant number of these stars.  This will allow, for the first time, accurate models of how these stars evolve.

Friday, January 7, 2011

Maturity of SIM Hardware

   The technology necessary to carry out the SIM mission is at a high degree of readiness.  The following status report for the SIM project demonstrates the level of effort that has gone into getting the project ready to proceed to Phase C. The SIM team has built actual hardware that could be qualified for flight.

SIM Progress Report

   This mission represents the best way for NASA to fulfill the recommendations of the 1990 and 2000 Astrophysics Decadal reports.  It is also the best way to implement the Exoplanet roadmap put forward by NASA's Exoplanet Task Force in 2007.

Thursday, January 6, 2011

Alternative Earths

SIM will truly usher in the age of Exo-Geology.  Here is a link to an article that describes the variety of geological styles that Other Earths may exhibit.

Alternative Earths

   So far, we have only been able to study 2 Earth-Sized terrestrial planets, i.e., Earth and Venus.  The "New Earths" discovered by SIM will, over the long term, revolutionize Geology.  We have seen on Venus a version of Plate Tectonics that resembles that on the Earth, but which is not identical.  Intriguing, but we will probably need to examine 10 or 20 Earths to pin down, with some detail, exactly which geological factors have determined the appearance, and environment, of our home planet.  The road to this revolution begins with SIM.  Over the years, and decades, and centuries, SIM will initially be followed by space telescopes that will produce crude maps of these Other Earths, leading eventually to direct probes to those far-off worlds.  
     We will see a variety of "Earths" that will open up a new frontier. These worlds could be in geological stages that are equivalents of the Earth's long series of geological epochs.  These include the Archean, when the Earth was devoid of life; several episodes of "Snowball Earth" conditions; the Cambrian, when multi-celled life first appeared; the Mesozoic age of Dinosaurs; recovery from Giant Impacts; the Miocene worlds of Mammals before humans; the present epoch of Human Dominance; possible post-industrial epochs.
   We will be able to examine those alternative worlds by having the will to start the process of Exploration, and that process begins with SIM.