Tuesday, August 7, 2018
NASA's New Interstellar Dust Mission (IMAP) Puts University of Colorado Into Space Spotlight Again
A member of the CU calibration team for the LASP Dust Accelerator, works in the latge experimental chamber for an upcoming experiment in Boulder, CO.
The University of Colorado's Laboratory for Atmospheric and Space Sciences (LASP) has again earned a notch for success under its space mission belt. This time as its selection to spearhead the supporting science for the 2024 NASA Interstellar Mapping and Acceleration Probe (IMAP) aimed at studying the particles streaming toward Earth from the boundaries of interstellar space.
This key role in the upcoming IMAP mission was earned in part through LASP's performance for NASA in the 2015 Magnetospheric Multiscale Mission, e.g.
NASA's Magnetospheric Multiscale Mission surpasses expectations …
- which launched four identical spacecraft into orbit around Earth to study the phenomenon of magnetic reconnection.
In the case of Earth's magnetosphere, e.g.
magnetic reconnection enters by way of incoming solar wind plasma interacting with the Earth's magnetic field. By this concept, the interplanetary magnetic field divides or disconnects at an "X-line" at the magnetopause with one end going over the north pole and the other the south pole. These polar lines are called "open" with only one end connected to Earth - as the graphics indicate. In each case the total amount of open flux must conform to Maxwell's equations, see e.g.
Generalizing, a similar X-line is proposed to occur in the magnetotail with the two ends hypothesized to reconnect with a return flow of plasma and magnetic flux occurring toward Earth. The purpose of the IMAP mission - according to NASA - will be to help researchers better understand the boundary of the heliopause.
The heliopause is the interface where the solar wind is stopped by the interstellar medium. One can therefore think of it as a three dimensional region or surrounding “envelope” at which the solar wind's strength is no longer sufficient to overcome the stellar winds of the external stars. In technical terms, this absence of counter-pressure signals the end of the solar system. In more lay parlance, one can think of it as a sort of "magnetic bubble" or cosmic "filter" which surrounds and protects the solar system. It protects in the sense of limiting the amount of harmful cosmic radiation that enters the heliosphere.
The $492 m IMAP craft will do its thing from a 'parking space' known as a Lagrange point about 1 million miles in the sunward direction from Earth. There are 5 Lagrange points in all, and the sunward point (L1) is identified in the graphic below:
From that L1 location IMAP will collect and analyze the particles that make it through. CU's LASP researchers will be leading the science operations, as well as providing most of the 10 instruments (see topmost graphic) that represent the payload. Work is already well underway at LASP in designing and building one of the critical instruments, the Interstellar Dust Experiment known as IDEX. This is a high resolution compositional dust analyzer that provides data on speed and mass distributions for the incoming interstellar particles.
According to Daniel Baker, CU's LASP Director who will serve as the lead science investigator, quoted in The Denver Post:
"We'll be commanding all the scientific instruments, the acquisition of the data through the mission's science team - and through the broader science community. We're very proud that all the scientific roads for IMAP will lead to CU and LASP."
"We've proved ourselves because of the cost - effectiveness and the vast experience of LASP in dealing with scientific data acquisition and distribution. LASP has just hit it out of the park as far as doing the right thing and bridging the gap between operations and science."
Readers can learn more about the various space projects at LASP here:
Undoubtedly, the most intriguing instrument is the IDEX, which has been described (ibid.) as "about the size of a modest bucket of just 40 cm diameter and a price tag of $15 million". The principal investigator for this instrument is Mihaly Horanyi, a CU physics professor and LASP member. The co-investigators are Sascha Kempf - a CU associate professor - and Zoltan Sternovsky, a CU professor of aerospace engineering.
Horanyi cites Stephen J. Gould in explaining why the composition of interplanetary dust particles matters, i.e.:
"How can you appreciate a castle if you don't cherish all the building blocks?"
"They are the original bricks of our solar system. We were formed from a collapsing gas and dust cloud and these little bitty pieces survived and they are still coming through the solar system. They are truly the roots and origins of the solar system we live in."
For observational astronomers the importance of interstellar dust has primarily been via the phenomenon of reddening or a dimming of starlight by extinction. Thus, the shorter blue wavelengths are scattered more than longer (red) wavelengths. (An analogous illustration is the Sun observed when near the horizon, say at sunset. )
Dust itself is believed to be primarily composed of hydrogen, oxygen, carbon, nitrogen and silicon. Thus, interstellar dust contains the same elements common to the interstellar gas in the general forms of ices, silicates, graphite and metals such a iron. Some dust grains also contain organic compounds.
The NASA IMAP project will be able to answer many more questions including how hydrogen molecules (the same molecules which are most prominent in giant molecular clouds) form on interstellar dust grains.